Hydraulics & Pneumatics - Hydraulics & Pneumatics is the leading international technical resource for fluid power http://hydraulicspneumatics.com/rss.xml en Reducing the Cost of Compressed Air http://hydraulicspneumatics.com/air-compressors/reducing-cost-compressed-air <div class="field-deck"> Sponsored by Exair </div> <div class="node-body article-body"><p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/05/EXAIRlogo-243x50.gif" style="width: 200px; height: 41px; float: right;" />What tasks do manufacturers do with compressed air? And could they do those tasks more efficiently? What would be the first step companies should take regarding compressed air? After fixing leaks, what&rsquo;s the next big step in not wasting compressed air? Are newer, more efficient compressed-air devices available? Are there other steps plant managers can take to save money on compressed air?</p> <p>Download <em><strong>FAQs on Reducing the Cost of Compressed Air</strong></em> sponsored by <strong>Exair</strong> to get the answers.</p> <script type="text/javascript"> document.write('\ <iframe style="height: 900px; width: 100%; border:0;” frameBorder="0" scrolling="no"\ src="http://pages.hydraulicspneumatics.com/HP_FAQ_Exair_CostCompressedAir_WP_JoR_061316?partnerref=' + getParameterByName("partnerref") + "&elq=" + getParameterByName("elq2") + "&code=" + getParameterByName("code") + "&PK=" + getParameterByName("PK") + "&PR=" + getParameterByName("PR") + '"></iframe>'); function getParameterByName(name) { var match = RegExp('[?&]' + name + '=([^&]*)').exec(window.location.search); if (match == null) return ""; return match && decodeURIComponent(match[1].replace(/\+/g, ' ')); } </script></div> http://hydraulicspneumatics.com/air-compressors/reducing-cost-compressed-air#comments Air Compressors Design FAQs Maintenance Fittings & Couplings Other Components Wed, 29 Jun 2016 19:07:00 +0000 38721 at http://hydraulicspneumatics.com FREE Software Helps You Draw Fluid Power Schematics http://hydraulicspneumatics.com/blog/free-software-helps-you-draw-fluid-power-schematics <div class="node-body blog-body"><p>One of the most frequent inquiries that comes my way is where to find inexpensive software for drawing hydraulic and pneumatic schematics. I&#39;ve seen many good ones come and go through the years, and it&#39;s hard to keep track of what&#39;s currently available.</p> <p><a href="/site-files/hydraulicspneumatics.com/files/uploads/2016/04/%20DraftSight.png"><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/04/%20DraftSight.png" style="width: 333px; height: 240px; float: right; margin-left: 4px; margin-right: 4px;" title="Click on image for larger view." /></a>Many programs have some fantastic features. Unfortunately, they are accompanied by fantastic price tags. Most of this high-end software has simulation capabilities, and if that&#39;s not something you need, you won&#39;t watn to pay for it.</p> <p>How does <strong>FREE</strong> sound? I know, you get what you pay for, so if software is free, it probably won&#39;t do much. Either that, or it&#39;s so commercial that you can only use it with the vendor&#39;s products.</p> <p>However, I recently learned of a free computer-aided drafting program called DraftSight, from Softonic Internacional SA. Go to <strong><a href="http://draftsight.en.softonic.com/" target="_blank">draftsight.en.softonic.com</a></strong> to read about it.</p> <p>DraftSight lets you construct drawings that can be saved and exported or converted into a variety of formats. I didn&#39;t see anything about a library of common fluid power symbols, but once you&#39;ve drawn a valve or group of components (such as a hydraulic power unit), you could save it and make your own fluid power library. You could probably even go to a users group and share symbols with others.</p> <p>One feature most potential users want is an automatic bill of materials. I haven&#39;t dug deep enough to find out if DraftSight offers this, and it may be an add-on feature or part of an add-on package.</p> <p>But don&#39;t take my word for it. <strong><a href="http://draftsight.en.softonic.com/comments" target="_blank">Click here</a></strong> to go to a page of reviews. Keep in mind, though, that the reviews are housed on Softonic&#39;s website, so they could&#39;ve edited out any negative reviews.</p> </div> http://hydraulicspneumatics.com/blog/free-software-helps-you-draw-fluid-power-schematics#comments Other Technologies The Hitch Post Sat, 25 Jun 2016 16:42:00 +0000 38961 at http://hydraulicspneumatics.com Distributor Joint Annual Summit Set for September http://hydraulicspneumatics.com/news/distributor-joint-annual-summit-set-september <div class="node-body article-body"><p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/04/fpda-isd-web-banner-final.jpg" style="width: 594px; height: 169px; margin: 3px;" /></p> <p>The 2016 <a href="http://www.fpda.org/aws/FPDA/pt/sp/home_page" target="_blank">Fluid Power Distributors Association</a> (FPDA)-<a href="http://isd.org/aws/ISD/pt/sp/home_page" target="_blank">International Sealing Distribution</a> Association (ISD) Joint Annual Summit is scheduled to occur September 18-21 at the Westin Savannah in Savannah, Georgia.&nbsp; The summit is open to distributor and associate/affiliate members, as well as distributor and associate/affiliate non-members. Suppliers may also register, along with spouses and companions. <a href="http://fpda.org/aws/FPDA/pt/sp/memservices_summit_register" target="_blank">Registration</a> ends August 19.</p> <div class="related-content"> <div class="related-label">Related</div> <p><a href="http://hydraulicspneumatics.com/other-technologies/fpda-elects-new-leaders">FPDA elects new leaders</a></p> <p><a href="http://hydraulicspneumatics.com/waste-management/waste-expo-2016-unveil-latest-industry-wide-innovations ">Waste Expo 2016 to Unveil Latest Industry-Wide Innovations</a></p> <p><a href="http://hydraulicspneumatics.com/other-technologies/offshore-technology-conference-open-industry-professionals-students-alike">Offshore Technology Conference Open to Industry Professionals, Students Alike</a></p> </div> <p>Themed <em>Navigating Today for Tomorrow&rsquo;s Opportunities</em>, the summit provides an opportunity for business professionals to meet and discuss strategies to increase profits, examine value-added selling techniques, and look toward a bright future in distribution services. Visitors can attend a range of social and educational events that will help them network and learn more about the future of their industry. It also opens the doors for&nbsp;Emerging Leaders and Young Executives members, also known as YES and ELI, to discuss plans for growing their businesses and serving a growing customer base, which gains between 50- and 100-million distributors every year.</p> <p><strong>Events </strong></p> <p>Registration begins on Sunday at 11:00 am and ends at 7:00 pm. During the day, visitors can attend an FDPA board meeting from 2:00 to 4:30, followed by the First-Timers Orientation at 5:00, and the Joint Welcome Reception at 5:30 until 7:00. Then, at 7:30, YES/ELI and FPDA/ISD members are invited to depart by ferry en route to the Haunted pub crawl. Additional fees and pre-registration is required for this event.</p> <p>Then, on Monday, September 19, Herb Meyer, author of <a href="http://www.howtoanalyzeinformation.com/How_To_Analyze_Information/How_To_Analyze_Information_by_Herb_Meyer.html" target="_blank"><em>How to Analyze Information</em></a> will open the summit by discussing contemporary issues in national security, the economy, culture, and other areas. Workshops will proceed throughout the rest of the day, including <em>The Real Profit Drivers: An In-Depth Review of What Really Impacts Profit</em>, presented by Al Bates<em>, </em>and<em> Value Added Selling i</em><em>n a Tough Economy</em>, presented by Paul Reilly. An ELI/YES Joint Luncheon<em> will proceed at noon. Finally, the </em>FPDA/ISD Supplier Showcase and Networking Reception will occur from 4:30 until 6:30.</p> <p>There will be a range of fun events taking place at the summit on Tuesday, including a golf tournament at The Club at Savannah Harbor, and a Savannah highlights tour called Midnight in the Garden of Good and Evil. Registration is required for both events. Finally, at 7:00, a 1920s-themed murder mystery and dinner will be hosted by Odd Lot, a Savannah improvisation team that was voted best comedy group of the year six times. The show&rsquo;s plot will be guided by the audience&rsquo;s suggestions, and will conclude with everyone guessing the murderer, the motives, and the methods of the crime. Persons who guess right will win a prize.</p> <p>The summit will conclude on Wednesday after a FPDS/IDS continental breakfast at 8:30 and a closing session&nbsp;<em>featuring</em> motivational business speaker,&nbsp;<a href="http://www.rossbernsteinspeaking.com/" target="_blank">Ross Bernstein</a> at 9:00. FPDA members are also invited to attend a closing board meeting from 10:45 until noon.&nbsp;</p> <p><span style="font-size: 12.8px; line-height: 20px;">An overview of the</span><span style="font-size: 12.8px; line-height: 20px;">&nbsp;</span>agenda for 2016&nbsp;is available<a href="http://www.fpda.org/aws/FPDA/pt/sp/memservices_summit_agenda" target="_blank"> here</a><span style="font-size: 12.8px; line-height: 20px;">.</span></p> </div> http://hydraulicspneumatics.com/news/distributor-joint-annual-summit-set-september#comments News Fri, 24 Jun 2016 01:17:00 +0000 38951 at http://hydraulicspneumatics.com Hydraulics & Pneumatics Products of the Week (6/23-6/30) http://hydraulicspneumatics.com/pneumatic-valves/hydraulics-pneumatics-products-week-623-630 <div class="node-body gallery-body"><p>Hydraulics &amp; Pneumatics&#39; product gallery includes high-pressure hydraulic components,&nbsp;diecast aluminium&nbsp;precision regulators,&nbsp;closed-circuit axial-piston pumps, counterbalance valves, and rotary vacuum pumps.&nbsp;</p> </div> http://hydraulicspneumatics.com/pneumatic-valves/hydraulics-pneumatics-products-week-623-630#comments Products Hydraulic Pumps & Motors Pneumatic Valves Fri, 24 Jun 2016 00:56:00 +0000 38941 at http://hydraulicspneumatics.com Principios Ingenieriles Básicos: Motores Hidráulicos http://hydraulicspneumatics.com/blog/principios-ingenieriles-b-sicos-motores-hidr-ulicos <div class="node-body blog-body"><p class="rtejustify">Los motores hidr&aacute;ulicos transforman energ&iacute;a cin&eacute;tica del fluido en energ&iacute;a mec&aacute;nica rotativa, la cual generalmente es aplicada a una carga mediante un eje.</p> <p class="rtejustify">Todos los motores hidr&aacute;ulicos tienen caracter&iacute;sticas de dise&ntilde;o similares: una superficie de accionamiento sujeta a presi&oacute;n diferencial,&nbsp;una manera de sincronizar la conexi&oacute;n entre fluido a presi&oacute;n hacia la superficie de presi&oacute;n para lograr una rotaci&oacute;n continua&nbsp;y una conexi&oacute;n mec&aacute;nica entre esta superficie y el eje.</p> <p class="rtejustify">La capacidad de la superficie de presi&oacute;n de soportar fuerza, las caracter&iacute;sticas de fuga interna de cada tipo de motor, y la eficiencia del m&eacute;todo utilizado para conectar la superficie de presi&oacute;n con el eje, determinan el m&aacute;ximo desempe&ntilde;o de un motor en t&eacute;rminos de presi&oacute;n, caudal, torque de salida, velocidad, eficiencias mec&aacute;nica y volum&eacute;trica, vida &uacute;til, y configuraci&oacute;n f&iacute;sica.</p> <p class="rtejustify"><strong>Terminolog&iacute;a</strong></p> <p class="rtejustify">El <em>desplazamiento</em> del motor se refiere al volumen de fluido requerido para rotar el eje una revoluci&oacute;n. Las unidades m&aacute;s com&uacute;nmente utilizadas para el desplazamiento son pulgadas c&uacute;bicas (in<sup>3</sup>), o cent&iacute;metros c&uacute;bicos (cc) por revoluci&oacute;n. El desplazamiento puede ser fijo o variable, al igual que las bombas. Un motor de desplazamiento fijo entrega un torque constante. Al variar el caudal que entra al mismo, var&iacute;a su velocidad. Si mantenemos el caudal de entrada y presi&oacute;n constantes, al variar el desplazamiento podemos modificar la relaci&oacute;n torque-velocidad para alcanzar los requerimientos de carga.</p> <p class="rtejustify">El <em>torque de salida</em> se expresa en pulgadas-libras fuerza (<em>in-lbf), </em>o pies-libras fuerza (<em>ft-lbs)</em>. Est&aacute; directamente relacionado a la presi&oacute;n del sistema y el desplazamiento del motor. Las capacidades de torque de motores est&aacute;n generalmente dadas por deltas de presi&oacute;n espec&iacute;ficas. Los datos te&oacute;ricos indican el torque disponible en el eje, asumiendo que no hay p&eacute;rdidas mec&aacute;nicas.</p> <p class="rtejustify">El <em>par de arranque</em> es el torque requerido para iniciar el movimiento de una carga estacionaria. Se requiere m&aacute;s torque para iniciar el movimiento de la carga que para mantenerlo.</p> <p class="rtejustify">El <em>torque de operaci&oacute;n</em> puede referirse a la carga aplicada al motor o la carga del motor mismo. Cuando se refiere a la carga, indica el torque requerido para mantenerla en movimiento. Cuando se refiere al motor, indica el torque que puede desarrollar un motor para mantener una carga en movimiento. Este torque considera la ineficiencia del motor y es un porcentaje del torque te&oacute;rico. Para motores comunes de engranajes, paleta y pist&oacute;n, esta cifra es de aproximadamente el 90%.</p> <p class="rtejustify">El <em>torque de arranque</em> se refiere a la capacidad de un motor hidr&aacute;ulico para mover una carga desde el reposo. Indica el torque que un motor puede desarrollar para ejecutar esta acci&oacute;n. Puede ser expresado tambi&eacute;n como un porcentaje del torque te&oacute;rico&nbsp; y ronda entre 70% y 80% para motores de engranajes, paletas y pistones comunes.</p> <p class="rtejustify">La <em>eficiencia mec&aacute;nica</em> es la relaci&oacute;n entre el torque real y el te&oacute;rico.</p> <p class="rtejustify">El <em>rizado de par o de torque </em>es la diferencia entre el torque m&iacute;nimo y m&aacute;ximo entregado a una presi&oacute;n espec&iacute;fica en una revoluci&oacute;n del motor.</p> <p class="rtejustify">La <em>velocidad del motor</em> es funci&oacute;n del desplazamiento del mismo y el caudal entregado a &eacute;ste.</p> <p class="rtejustify">La <em>velocidad m&aacute;xima del motor</em> es aqu&eacute;lla, a una presi&oacute;n espec&iacute;fica a la entrada, que el motor puede mantener por un tiempo limitado sin que se produzcan da&ntilde;os en el mismo.</p> <p class="rtejustify">La <em>velocidad m&iacute;nima del motor</em> es la velocidad rotacional m&aacute;s lenta, continua y sin interrupci&oacute;n que el motor puede entregar por el eje.</p> <p class="rtejustify">El <em>deslizamiento</em> es la fuga a trav&eacute;s del motor, o el fluido que pasa a trav&eacute;s del mismo sin producir trabajo.</p> <p class="rtejustify"><strong>Motores de engranajes</strong></p> <p class="rtejustify">Los <em>motores de engranajes externos</em> consisten en un par de ruedas de engranajes acopladas dentro de una carcasa (Fig. 1). Ambas tienen dientes con la misma forma y son accionados por fluido hidr&aacute;ulico. Una de ellas, al igual que en las bombas de engranajes externos, est&aacute; conectada al eje principal mientras que la otra es neutra. Fluido a presi&oacute;n ingresa a la carcasa en el punto que los dientes se acoplan, lo que ejerce una fuerza contra los mismos que hace que las ruedas giren. Luego el mismo sigue el camino de menor resistencia por la periferia de la carcasa y sale a baja presi&oacute;n por el lado opuesto del motor. Las tolerancias entre los engranajes y la carcasa ayudan a controlar el nivel de fuga interna y a aumentar la eficiencia volum&eacute;trica. Platos de desgaste a los lados de los engranajes evitan que &eacute;stos se muevan axialmente e igualmente controlar la fuga interna.</p> <p class="rtejustify"><img alt="" src="http://hydraulicspneumatics.com/site-files/hydraulicspneumatics.com/files/uploads/2014/06/0714_HydMotors_F1.gif" style="width: 250px; height: 161px; margin: 10px; float: left;" title="Figura 1: El torque en motores de engranajes externos es función de la presión en un diente, ya que los otros se encuentran hidráulicamente balanceados." />Los motores <em>de engranaje interno</em> caen dentro de dos categor&iacute;as. Un motor tipo gerotor de acople directo consiste en un set de ruedas dentadas interna-externa (hembra-macho) y un eje (Fig. 2). La rueda interna tiene un diente menos que la externa y los dientes tienen una forma de manera tal que todos los dientes de la rueda interna est&eacute;n en contacto con alguna porci&oacute;n de la rueda externa en todo momento. Cuanto fluido a presi&oacute;n ingresa al motor, ambas ruedas giran. La carcasa tiene p&oacute;rticos integrados en forma de ri&ntilde;ones. Los centros de rotaci&oacute;n de las ruedas tienen una separaci&oacute;n espec&iacute;fica conocida como excentricidad. El centro de la rueda interna coincide con el del eje principal.</p> <p class="rtejustify"><img alt="" src="http://hydraulicspneumatics.com/site-files/hydraulicspneumatics.com/files/uploads/2014/06/0714_HydMotors_F2.gif" style="width: 250px; height: 195px; margin: 10px; float: right;" title="Figura 2: Un motor tipo gerotor de acople directo tiene tiene una rueda interna y otra externa. Ambas rotan durante la operación." />Fluido a presi&oacute;n entra al motor a trav&eacute;s del p&oacute;rtico de entrada (Fig. 2a). Como la rueda interna tiene un diente menos que la externa, se forma una cavidad entre los dientes internos 6 y 1 y el ancho del espacio&nbsp; de la rueda externa A. El p&oacute;rtico de entrada con forma de ri&ntilde;&oacute;n est&aacute; dise&ntilde;ado de manera que al maximizarse el volumen en esta cavidad, el flujo se detiene y se forma un sello entre los dientes internos 6 y 1 (Fig. 2b).</p> <p class="rtejustify">A medida que el par contin&uacute;a la rotaci&oacute;n, una nueva cavidad se forma entre los dientes internos 6 y 5 y el espacio G (Fig. 2c.). Mientras tanto, la cavidad formada entre los dientes 6 y 1 y el espacio A se ha movido al lado opuesto hacia el p&oacute;rtico de salida, constantemente drenando a medida que el volumen de la cavidad disminuye. El cambio en volumen gradual en estas cavidades proporciona un flujo uniforme y suave con un m&iacute;nimo de variaci&oacute;n en la presi&oacute;n (u onda).</p> <p class="rtejustify">Debido al diente adicional de la rueda externa, le interna se mueve con una velocidad mayor por un diente por revoluci&oacute;n. En la Figura 2c, el diente interno 4 se apoya sobre el espacio E. En el pr&oacute;ximo ciclo, el diente interno 4 se apoyar&aacute; sobre el espacio F. Esto genera una velocidad relativa baja entre las ruedas.</p> <p class="rtejustify">Un <em>motor tipo gerotor orbitante </em>consiste en un set de engranajes en par, un acople, un eje y un conmutador o plato de distribuci&oacute;n (Fig. 3). El engranaje en la parte externa es estacionario y tiene un diente mas que la rueda interna. El conmutador gira a la misma velocidad que la rueda interna y continuamente provee fluido a presi&oacute;n y un pasadizo a tanque a las cavidades que as&iacute; lo requieran entre ambas ruedas.</p> <p class="rtejustify"><img alt="" src="http://hydraulicspneumatics.com/site-files/hydraulicspneumatics.com/files/uploads/2014/06/0714_HydMotors_F3.gif" style="width: 250px; height: 186px; margin: 10px; float: left;" title="Figura 3: Motor tipo gerotor orbitante. " />Durante la operaci&oacute;n, el diente 1 de la rueda interna se alinea en el espacio D de la externa (Fig. 3.a). El punto y es el centro de la rueda estacionaria y el punto x es el centro del rotor. Si no hubiese fluido, el rotor pivotear&iacute;a libremente sobre el espacio D en cualquier direcci&oacute;n. Se podr&iacute;a mover asentando el diente 2 en el espacio E o de igual manera el diente 6 en el espacio J.</p> <p class="rtejustify">Cuando fluido a presi&oacute;n se desplaza hacia la mitad posterior del volumen entre las ruedas, si se provee un camino a tanque al volumen de la mitad superior, se induce un momento que rota la rueda interna contra-reloj y causa que el diente 2 se apoye en el espacio E. El diente 4, en el instante mostrado en la Fig. 3a, proporciona un sello entre fluido de presi&oacute;n y retorno.</p> <p class="rtejustify">Sin embargo, a medida que la rotaci&oacute;n contin&uacute;a, el lugar geom&eacute;trico del punto x es en el sentido de las agujas del reloj. Cuando cada diente del rotor se va acoplando a su espacio, el mismo ubicado directamente opuesto a este se convierte en el sello entre fluido a presi&oacute;n y retorno (Fig. 3b). El fluido a presi&oacute;n contin&uacute;a forzando al rotor a acoplarse en direcci&oacute;n horario mientras rota en sentido anti-horario.</p> <p class="rtejustify">Debido al espacio adicional en el engranaje fijo (rueda externa), la pr&oacute;xima vez que el diente 1 se asiente o acople, ser&aacute; en el espacio J. En ese punto, el eje ha girado un s&eacute;ptimo de revoluci&oacute;n y el punto &lsquo;x&rsquo; lo ha hecho seis s&eacute;ptimos de circunferencia. En la figura 3c, el diente 2 se acopla al espacio D y el punto x se alinea nuevamente entre el espacio D y el punto &lsquo;y&rsquo;, indicando que el rotor ha dado una vuelta completa dentro de la rueda externa. El diente 1 se ha movido un &aacute;ngulo de 60&deg; de su punto original en la Fig. 3&ordf;. 42 (o 627) acoples de dientes o ciclos de fluido ser&iacute;an necesarios para que el eje de una vuelta completa.</p> <p class="rtejustify">El plato de distribuci&oacute;n o control tiene pasadizos de presi&oacute;n y retorno para cada diente del rotor (Fig. 3d, e y f). Los mismos est&aacute;n espaciados de manera que no provean caudal de presi&oacute;n o retorno a cada p&oacute;rtico a medida que los dientes se asienten en su espacio. En otros momentos, &eacute;stos son bloqueados o proveen de fluido a presi&oacute;n o paso a tanque a la mitad correspondiente del motor entre engranajes.</p> <p class="rtejustify"><img alt="" src="http://hydraulicspneumatics.com/site-files/hydraulicspneumatics.com/files/uploads/2014/06/0714_HydMotors_F4.gif" style="width: 250px; height: 144px; margin: 10px; float: right;" title="Figura 4: El motor tipo gerotor de paletas rotativas incorpora paletas que reducen el desgaste." />Un <em>motor gerotor de paletas rotativas</em> es una variaci&oacute;n del motor gerotor orbitante (Fig. 4). Tiene un anillo estacionario (o estator) y una rueda dentada planetaria (o rotor). En lugar de estar soportado por dos cojinetes lisos, el brazo exc&eacute;ntrico del planetario se mantiene en su lugar por el acople del rotor de seis dientes y estator de 7 espacios. En vez de tener un contacto directo entre el estator y el motor, paletas rotativas son incorporadas para formar las c&aacute;maras de desplazamiento. &Eacute;stas paletas reducen el desgaste, permitiendo que los motores san utilizados en sistemas hidrost&aacute;ticos de circuito cerrado a alta presi&oacute;n para aplicaciones de accionamiento de ruedas con acople directo.</p> <p class="rtejustify"><strong>Motores de paletas</strong></p> <p class="rtejustify">Los <em>motores de paleta</em> tienen un rotor con agujeros montado en un eje que acciona el mismo (Fig. 5). Paletas, estrechamente introducidas en las cavidades del rotor se desplazan radialmente sellando contra el anillo. &Eacute;ste cuenta con dos secciones mayores y dos menores radiales unidas mediante secciones de transici&oacute;n o rampas. Los contornos y las presiones introducidas se balancean diametralmente (al igual como ocurre en las bombas de paletas balanceadas).</p> <p class="rtejustify"><img alt="" src="http://hydraulicspneumatics.com/site-files/hydraulicspneumatics.com/files/uploads/2014/06/0714_HydMotors_F5.gif" style="width: 250px; margin: 10px; float: left; height: 152px;" title="Figura 5: Motor de paletas de diseño balanceado" />Algunos dise&ntilde;os incluyen resortes de baja tensi&oacute;n que fuerzan a las paletas contra el anillo para garantizar el sellado cuando no est&eacute; en movimiento, de manera que el motor pueda desarrollar torque de arranque. Los resortes son asistidos por la fuerza centr&iacute;fuga a velocidades m&aacute;s altas. Ranuras y agujeros radiales a trav&eacute;s de las paletas equilibran&nbsp;las fuerzas radiales en las mismas en todo momento.</p> <p class="rtejustify">Fluido a presi&oacute;n ingresa y sale de la carcasa del motor a trav&eacute;s de aperturas en los platos laterales en las rampas mencionadas anteriormente. El fluido que ingresa por el p&oacute;rtico de entrada mueve al rotor en sentido anti-horario en este caso. El rotor transporta al fluido hacia las aperturas de rampa en los p&oacute;rticos de salida para regresar a tanque. Si la presi&oacute;n fuese introducida por &eacute;stos p&oacute;rticos, el motor rotar&iacute;a en sentido horario.</p> <p class="rtejustify">La separaci&oacute;n axial del rotor y los platos laterales se logra mediante la presencia de una pel&iacute;cula de aceite. El plato frontal se encuentra sostenido contra el anillo mediante la presi&oacute;n y mantiene una separaci&oacute;n optima incluso con cambios en la misma y temperatura.</p> <p class="rtejustify">Los motores de paletas presentan buenos niveles de eficiencia, aunque no tan altos como la de los de pistones. Sin embargo, el costo de estos es generalmente menor a caballajes comparativos. Ahora, la vida &uacute;til de un motor de paletas es generalmente mas corta que la de uno de pistones. Los motores de paletas por lo general tienen una capacidad limitada a baja velocidad.</p> <p class="rtejustify"><strong>Motores de pistones</strong></p> <p class="rtejustify">Los <em>motores de pistones radiales</em> tienen un barrilete o cilindro unido a un eje (Fig. 6). El mismo contiene un numero de pistones que reciprocan en cavidades radiales. El lado externo de los pistones se apoyan sobre un anillo impulsor. El fluido a presi&oacute;n ingresa a trav&eacute;s de un pin ubicado en el centro del cilindro para accionar los pistones hacia fuera. Estos son entonces presionados contra el anillo impulsor y las fuerzas reactivas generan rotaci&oacute;n en el barrilete.</p> <p class="rtejustify"><img alt="Figura 6" src="http://hydraulicspneumatics.com/site-files/hydraulicspneumatics.com/files/uploads/2014/06/0714_HydMotors_F6.gif" style="width: 250px; height: 187px; margin: 10px; float: right;" title="Figura 6: Motor de Pistones Radiales" />Al mover el bloque de deslizamiento en direcci&oacute;n lateral, se cambia la carrera de los pistones, lo que por ende causa un cambio en el desplazamiento del motor. Cuando la l&iacute;nea central del barrilete y la carcasa coinciden, el flujo se anula, por lo que el cilindro se detiene. Al mover el bloque fuera de centro hacia el otro lado invierte la direcci&oacute;n de rotaci&oacute;n.</p> <p class="rtejustify">Los motores de pistones radiales son muy eficientes. A pesar de que se requiere un nivel alto de precisi&oacute;n en la fabricaci&oacute;n y que esto implica costos elevados&nbsp; de manufactura, por lo general tienen una vida &uacute;til larga. Proporcionan un torque alto a velocidades relativamente bajas y una excelente operaci&oacute;n a baja velocidad con una alta eficiencia. Cabe destacar que tienen limitaciones en lo que respecta a velocidades altas.</p> <p class="rtejustify">Los <em>motores de pistones axiales</em> tambi&eacute;n utilizan el principio de movimiento reciprocante para accionar el eje principal, pero lo hace de manera axial en vez de radial. Sus caracter&iacute;sticas en cuanto a la eficiencia son similares a las de los motores de pistones radiales. Presentan un costo que inicialmente es mas alto que los de paletas o engranajes de caballaje comparable. Al igual que los de pistones radiales, presentan una vida &uacute;til larga por lo que el costo alto inicial no refleja verdaderamente los costos generales esperados durante la vida &uacute;til del equipo.</p> <p class="rtejustify">Por lo general, los motores de pistones axiales presentan excelente capacidad a altas velocidades. A diferencia de los motores de pistones radiales, presentan como se esperaba, limitaciones a bajas velocidades. Por lo general, los motores de configuraci&oacute;n en l&iacute;nea operan sin problemas a velocidades tan bajas como las 100 rpm y los de eje inclinado hasta 4 rpm.</p> <p class="rtejustify">Los motores <em>de pistones en l&iacute;nea</em> generan torque mediante presi&oacute;n aplicada en los extremos de los pistones que reciprocan en un cilindro o barrilete (Fig. 7). En este dise&ntilde;o, el eje del motor y el cilindro se encuentran alineados en la misma accisa. La presi&oacute;n en los extremos de los pistones generan una reacci&oacute;n contra un basculante inclinado, lo cual rota el cilindro y por ende el eje. El torque es proporcional al &aacute;rea de los pistones y es una funci&oacute;n del &aacute;ngulo de posici&oacute;n del basculante.</p> <p class="rtejustify"><img alt="" src="http://hydraulicspneumatics.com/site-files/hydraulicspneumatics.com/files/uploads/2014/06/0714_HydMotors_F7.gif" style="width: 250px; height: 126px; margin: 10px; float: right;" title="Figura 7: Motor de pistones axiales, en línea" />Estos motores se construyen en variaciones de desplazamiento fijo o variable. El &aacute;ngulo del basculante y el tama&ntilde;o de los pistones determinan el desplazamiento del motor. En la versi&oacute;n variable, el basculante esta montado sobre un pivote y su &aacute;ngulo puede ser variado de diversas formas que oscilan desde mandos mec&aacute;nicos simples, hasta controladores servo. Al aumentar el &aacute;ngulo del basculante se incrementa el torque pero reduce la velocidad; al reducirlo se reduce el torque y aumenta la velocidad (esto si se mantiene la presi&oacute;n constante). Existen opciones de limitaci&oacute;n mec&aacute;nica del &aacute;ngulo, de manera que se mantengan dentro de los limites operativos deseados.</p> <p class="rtejustify">Un regulador varia el desplazamiento del motor en respuesta a cambios en la carga. Un pist&oacute;n precargado por un resorte se conecta al pivote del basculante y lo mueve de acuerdo a variaciones en la presi&oacute;n de operaci&oacute;n. Cualquier aumento en carga generara una subida de presi&oacute;n como resultado de la necesidad de torque. El regulador autom&aacute;ticamente ajusta el &aacute;ngulo de manera que el torque disminuya cuando la carga sea ligera. Idealmente el regulador controla el desplazamiento para proporcionar un m&aacute;ximo desempe&ntilde;o bajo condiciones variables de carga hasta la presi&oacute;n establecida por la v&aacute;lvula de alivio.</p> <p class="rtejustify">Los <em>motores de pistones axiales de eje inclinado</em> generan torque como resultado de una reacci&oacute;n a presi&oacute;n sobre pistones reciprocantes (Fig. 8). En este dise&ntilde;o, el barrilete y el eje se encuentran instalados a un &aacute;ngulo entre si. La reacci&oacute;n es sobre la brida del eje.<img alt="" src="http://hydraulicspneumatics.com/site-files/hydraulicspneumatics.com/files/uploads/2014/06/0714_HydMotors_F8.gif" style="width: 300px; height: 195px; margin: 10px; float: right;" title="Figura 8: Motor de pistones axiales, eje inclinado" /></p> <p class="rtejustify">La velocidad y torque cambia con variaciones en el &aacute;ngulo, desde una velocidad m&iacute;nima predeterminada a un desplazamiento m&aacute;ximo y torque a un &aacute;ngulo de aproximadamente 30 grados, hasta una velocidad m&aacute;xima a un desplazamiento m&iacute;nima y torque a aproximadamente 7.5 grados. Est&aacute;n disponibles tanto en desplazamiento fijo como variable.</p> <p class="rtejustify"><strong>Selecci&oacute;n de un motor hidr&aacute;ulico</strong></p> <p class="rtejustify">La aplicaci&oacute;n de un motor hidr&aacute;ulico generalmente dicta los requerimientos en cuanto a velocidad y torque, a pesar de que estas caracter&iacute;sticas pueden a veces ser variadas manteniendo fija la potencia requerida. El tipo de motor seleccionado se hace en base a la confiabilidad requerida, vida &uacute;til esperada, y desempe&ntilde;o.</p> <p class="rtejustify">Una vez que se determine el tipo de fluido a utilizar, la selecci&oacute;n del tama&ntilde;o se hace en base a la vida &uacute;til esperada y la econom&iacute;a de la instalaci&oacute;n completa de la maquina en cuesti&oacute;n. Un motor operado por debajo de su capacidad presentara una extensi&oacute;n de vida &uacute;til mas que proporcional a cuanto representa la reducci&oacute;n en capacidad.</p> <p class="rtejustify">La potencia m&aacute;xima que presenta un motor se alcanza al operar a la m&aacute;xima presi&oacute;n y velocidad. Si el motor se va a operar siempre en estas condiciones, su costo inicial ser&aacute; mas bajo. En los casos en los que la velocidad deba ser reducida, se debe evaluar si el tiempo en el cual esto ocurre har&iacute;a necesario el redimensionamiento el motor en cuesti&oacute;n, a manera de optimizar los costos de instalaci&oacute;n.</p> <p class="rtejustify"><strong>Dimensionamiento de un motor hidr&aacute;ulico</strong></p> <p class="rtejustify">Como ejemplo de un dimensionamiento de un motor hidr&aacute;ulico para una aplicaci&oacute;n especifica, consideremos lo siguiente: una aplicaci&oacute;n requiere de 5 HP a 3,000 rpm, con una presi&oacute;n del sistema de 3,000 psi y una presi&oacute;n de retorno de 100 psi; el diferencial de presi&oacute;n es entonces de 2,900 psi. El torque te&oacute;rico requerido viene dado por:</p> <p class="rtejustify">T = (63,025 &times; hp)/N</p> <p class="rtejustify">Donde:</p> <p class="rtejustify">T es el torque en lb-in., y</p> <p class="rtejustify">N es la velocidad en rpm.</p> <p class="rtejustify">Para la condici&oacute;n arriba indicada, el torque resultante es de T = 105 lb-in., el desplazamiento del motor se calcula como:</p> <p class="rtejustify">D = 2&pi; T &divide; ∆P*eM</p> <p class="rtejustify">Donde:</p> <p class="rtejustify">D es el desplazamiento en, cc/rev</p> <p class="rtejustify">&nbsp;</p> <p class="rtejustify">∆P es la presi&oacute;n diferencial en psi y</p> <p class="rtejustify">eM es la eficiencia mec&aacute;nica en %.</p> <p class="rtejustify">Si la eficiencia mec&aacute;nica es del 88%, entonces D resulta en: 0.258 cu. in/rev.</p> <p class="rtejustify">Para calcular el caudal requerido, tenemos que:</p> <p class="rtejustify">Q = D*N/231*eV,</p> <p class="rtejustify">Donde:</p> <p class="rtejustify">Q es el caudal en gpm y</p> <p class="rtejustify">eV es la eficiencia volum&eacute;trica en %</p> <p class="rtejustify">Si la eficiencia volum&eacute;trica es del 93% (este es un factor caracter&iacute;stico de acuerdo al tipo de motor seleccionado, generalmente disponible por parte del fabricante), entonces el caudal Q es de 3.6 gpm.</p> <p class="rtejustify">Note que la presi&oacute;n utilizada en las ecuaciones es diferencial, es decir, la presi&oacute;n de entrada menos la presi&oacute;n de salida, por lo que cualquier aumento de presi&oacute;n a la salida disminuye el delta y por ende el torque de salida del motor.</p> <p class="rtejustify">El factor de eficiencia para la mayor&iacute;a de los motores es bastante constante cuando se opera de la mitad al total de la presi&oacute;n de dise&ntilde;o o en la porci&oacute;n del medio del rango de velocidad. A medida que la misma se acerca a los extremos, la eficiencia disminuye.</p> <p class="rtejustify">Bajas presiones de operaci&oacute;n resultan en eficiencias totales mas bajas por las perdidas internas de rotaci&oacute;n fijas, caracter&iacute;sticas de cualquier motor hidr&aacute;ulico. El reducir el desplazamiento en motores variables tambi&eacute;n reduce la eficiencia total.</p> <p class="rtejustify"><strong>Fallas en motores hidr&aacute;ulicos</strong></p> <p class="rtejustify">La mayor&iacute;a de las fallas en motores hidr&aacute;ulicos son causadas por la utilizaci&oacute;n de fluidos inapropiados, mantenimiento pobre, u operaci&oacute;n indebida. El motor no es diferente a los otros componentes del sistema hidr&aacute;ulico. Primero que todo debe contar con fluido limpio, en cantidades adecuadas y de la calidad y viscosidad correctas. Un programa inadecuado de mantenimiento es quiz&aacute;s la segunda causa de problemas. Fallas comunes en aquellos incluyen:</p> <ul> <li class="rtejustify">El no inspeccionar y reparar l&iacute;neas y conexiones para detener las fugas: malas conexiones pueden permitir el ingreso de contaminantes y aire en el sistema, baja presi&oacute;n y causar una operaci&oacute;n err&aacute;tica.</li> <li class="rtejustify">El no instalar el motor correctamente: un eje desalineado puede causar el desgaste prematuro de los rodamientos, lo genera una reducci&oacute;n en la eficiencia. Tambi&eacute;n podr&iacute;a generar una reducci&oacute;n en el torque, aumentar la fricci&oacute;n y calentamiento, resultando en una falla del eje.</li> <li class="rtejustify">El no encontrar la causa del mal funcionamiento del motor: si un motor falla, siempre trabaje en buscar la causa de la misma, por lo que en caso de no ser corregida, pues reincidir&aacute; en el futuro.</li> </ul> <p class="rtejustify">Es importante destacar que el exceder los limites de operaci&oacute;n promueve la falla del motor. Cada motor tiene limitaciones de dise&ntilde;o en cuanto a la presi&oacute;n, velocidad, torque, desplazamiento, carga y temperatura. Presi&oacute;n muy alta puede generar un calor excesivo debido a la fuga interna y causar que el motor opere por encima de sus limites de torque. Una velocidad excesiva podr&iacute;a calentar y desgastar rodamientos y otras partes internas. Un torque excesivo podr&iacute;a causar fatiga y esfuerzos en rodamientos y el eje, especialmente en aplicaciones que requieren una inversi&oacute;n constante en el giro. Una carga excesiva podr&iacute;a generar fatiga en los rodamientos y el eje. Y temperatura excesiva puede disminuir la eficiencia debido a la reducci&oacute;n en viscosidad del aceite, lo que genera una incremento en el desgaste por la falta de lubricaci&oacute;n, entre muchas otras cosas.</p> <p class="rtejustify">&nbsp;</p> </div> http://hydraulicspneumatics.com/blog/principios-ingenieriles-b-sicos-motores-hidr-ulicos#comments Motors & Actuators Hydraulic Pumps & Motors H&amp;P en tu idioma! Tue, 21 Jun 2016 19:20:00 +0000 38931 at http://hydraulicspneumatics.com Are You SURE Your Hydraulic Pump Is Broken? http://hydraulicspneumatics.com/blog/are-you-sure-your-hydraulic-pump-broken <div class="node-body blog-body"><p>When it comes to questions I get from members, there&#39;s a very valuable lesson contained in this one:<br /> <br /> <em>&quot;We have some problems with a Parker-Denison hydrostatic transmission pump P24S 2R1C 9A2. Oil temperature rises from 20 to 50 Celsius within 15-20 minutes of only light operation (65 bar working pressure). The pump was sent to a local workshop for repair and cost us $10,000 and yet the problem remains. The hydraulic repair shop sent an engineer to investigate but he couldn&#39;t solve it either. Any ideas?&quot;</em><br /> <br /> So the hydraulic pump wasn&#39;t the cause of the problem. Ouch! An expensive mistake. And one I&#39;ve seen made all too often by hydraulic equipment users. But is there really a problem here at all?<br /> <br /> Hydraulic oil temperature is rising to 50 Celsius within 20 minutes of operation. No big deal. Since this member is from Singapore, I would expect him to be using an ISO VG68 hydraulic oil. Depending on the viscosity index of the particular oil he&#39;s using, optimum operating viscosity is achieved between 55 and 78 Celsius. So after 20 minutes, the system isn&#39;t even at operating temperature. Of itself, no great cause for alarm.<br /> <br /> But why does this hydraulic system heat up so fast? Well this is a big transmission pump - 24 cubic inches or 400 cubic centimeters per rev. So it will have a big charge pump. As big as 4.8 cubic inches or 80 cubic centimeters per rev. If these pumps are turning at 1500 rpm and charge pressure is set at 23 bar, the charge pump is generating 4600 watts of pure heat load. That&#39;s equivalent to the power of two electric kettles.<br /> <br /> And being a hydrostatic transmission, it won&#39;t have a large reservoir - perhaps as small as half the available charge pump flow per minute. Which in this case, could be as little as 16 gallons or 60 liters. So the transmission&#39;s in-built heating element, a.k.a. charge pump, will soon warm up this volume of hydraulic oil - even with the transmission in neutral.<br /> <br /> Based on my long experience in the hydraulics biz, the whole issue of efficiency, heat-load and cooling - and its inter-relationship with viscosity and lubrication, is grossly misunderstood by hydraulic equipment end-users. And as the above example illustrates, it can get them into a heap of trouble. Costly too. And to discover six other costly mistakes you want to be sure to avoid with your hydraulic equipment, <a href="http://www.hydraulicsupermarket.com/track?p=handp&amp;w=smr"><strong>get &quot;Six Costly Mistakes Most Hydraulics Users Make... And How You Can Avoid Them!&quot; available for FREE download here</strong></a>.</p> </div> http://hydraulicspneumatics.com/blog/are-you-sure-your-hydraulic-pump-broken#comments Hydraulics At Work Tue, 21 Jun 2016 00:55:00 +0000 38911 at http://hydraulicspneumatics.com Designing Drives for a Competitive Edge http://hydraulicspneumatics.com/other-technologies/designing-drives-competitive-edge <div class="field-deck"> Sponsored by Gates </div> <div class="node-body article-body"><p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/Gates-Logo-262x77.gif" style="width: 180px; height: 53px; float: right;" />Read how two field retrofits led to better performing, more competitive drive designs by converting to Gates Poly Chain&reg; GT&reg; synchronous belt drive systems. One bottling facility saved $330,000 per year, while another manufacturing plant cut downtime, maintenance, and costs substantially.<br /> <br /> <a href="http://designcenter.gates.com/assets/designing-drives-white-paper/?utm_source=machinedesign.com&amp;utm_medium=email&amp;utm_campaign=design%20center%202016&amp;utm_content=dedicated%20email_designing%20drives"><strong>Download the Gates white paper</strong></a></p> </div> http://hydraulicspneumatics.com/other-technologies/designing-drives-competitive-edge#comments White Papers Other Technologies Other Components Mon, 20 Jun 2016 20:23:00 +0000 38831 at http://hydraulicspneumatics.com Selecting the Right Components for Harsh Environments http://hydraulicspneumatics.com/hose-tubing/selecting-right-components-harsh-environments <div class="field-deck"> Sponsored by Gates </div> <div class="node-body article-body"><p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/Gates-Logo-262x77.gif" style="width: 180px; height: 53px; float: right;" />Download Gates &ldquo;Selecting the Right Components for Harsh Environments&rdquo; white paper and discover cutting-edge solutions and product recommendations for increased ROI on your hydraulic hose assemblies and belt drive systems within extreme operating environments, such as oilfield, mining, marine, aggregate, and more.<br /> <br /> <a href="http://designcenter.gates.com/assets/maximizing-resources-white-paper/?utm_source=machinedesign.com&amp;utm_medium=email&amp;utm_campaign=design%20center%202016&amp;utm_content=dedicated%20email_maximizing%20resources" target="_blank"><strong>Download the Gates white paper</strong></a></p> </div> http://hydraulicspneumatics.com/hose-tubing/selecting-right-components-harsh-environments#comments White Papers Marine & Offshore Hose & Tubing Hydraulic Pumps & Motors Mon, 20 Jun 2016 19:51:00 +0000 38821 at http://hydraulicspneumatics.com Today’s Advanced Hose & Hydraulic Hose Systems http://hydraulicspneumatics.com/hose-tubing/today-s-advanced-hose-hydraulic-hose-systems <div class="field-deck"> Sponsored by Gates </div> <div class="node-body article-body"><p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/Gates-Logo-262x77.gif" style="width: 180px; height: 53px; float: right;" />Access &ldquo;Today&rsquo;s Advanced Hose and Hydraulic Systems&rdquo; white paper and discover innovative systems-approach solutions for your hydraulic system challenges&mdash;and why mismatching components from different manufacturers can make or break your bottom line.<br /> <br /> <em><strong><a href="http://designcenter.gates.com/assets/hydraulic-hose-system-white-paper/?utm_source=machinedesign.com&amp;utm_medium=email&amp;utm_campaign=design%20center%202016&amp;utm_content=dedicated%20email_hydraulic%20hose" target="_blank">Download&nbsp;the&nbsp;Gates white paper</a></strong></em></p> </div> http://hydraulicspneumatics.com/hose-tubing/today-s-advanced-hose-hydraulic-hose-systems#comments White Papers Hose & Tubing Hydraulic Fluids Hydraulic Pumps & Motors Mon, 20 Jun 2016 19:40:00 +0000 38811 at http://hydraulicspneumatics.com June 2016 http://hydraulicspneumatics.com/hydraulics-pneumatics/2016-06-17-0 <div class="node-body magazine_issue-body"></div> <fieldset class="fieldgroup group-mag-teasers"> <div class="field-mag-teaser"> <a href="/blog/fluid-power-gives-robot-arms-all-right-moves">Fluid Power Gives Robot Arms All the Right Moves</a> <a href="/cylinders-actuators/stick-slip-happens-how">Stick-Slip Happens, But How? </a> <a href="/hydraulic-pumps-motors/corn-processing-hits-new-speeds-hydraulics">Corn Processing Hits New Speeds With Hydraulics</a> </div> </fieldset> <fieldset class="fieldgroup group-publication-info"><legend>Publication Info</legend> </fieldset> Fri, 17 Jun 2016 04:00:00 +0000 38891 at http://hydraulicspneumatics.com Partnership Delivers Aerospace-Standard CAD-Model Catalog http://hydraulicspneumatics.com/other-components/partnership-delivers-aerospace-standard-cad-model-catalog <div class="node-body article-body"><p><a href="https://www.cadenas.de/en" target="_blank">CADENAS PARTsolutions</a> teamed up with the Society of Automotive Engineers (SAE) to produce the SAE MOBILUS digital catalog, which offers an array of Aerospace Standard (AS) computer-aided-design (CAD) models . The new catalog is available <a href="https://saemobilus.sae.org/" target="_blank">online through the SAE standards library</a>. It represents the latest addition to the PARTsolutions Strategic Parts Management software, which includes 600 other catalogs of manufacturer-certified digital components for download and direct configuration into existing designs.</p> <div class="related-content"> <div class="related-label">Related</div> <p><a href="http://hydraulicspneumatics.com/cylinders-actuators/comprehensive-hydraulic-pneumatic-cylinder-catalog-packed-specs">Comprehensive Hydraulic/ Pneumatic-Cylinder Catalog Packed with Specs</a></p> <p><a href="http://hydraulicspneumatics.com/200/TechZone/FluidPowerAcces/Article/False/88278/TechZone-FluidPowerAcces">Aerospace/defense sealing guide available </a></p> <p><a href="http://hydraulicspneumatics.com/pneumatic-valves/new-catalog-covers-vehicle-air-valves-controls">New Catalog Covers Vehicle Air Valves, Controls</a></p> </div> <p>The SAE MOBILUS catalog features parts in more than 150 native and neutral CAD and graphic formats. It works as a standalone system or in tandem with all product-lifecycle-management (PLM) and enterprise-resource-planning (ERP) platforms.</p> <p>The platform&rsquo;s built-in search function enables engineers to compare the geometry and metadata of individual parts. Parts are also searchable by geometry, topology, text, sketch, color, and other characteristics. Furthermore, the catalog can be navigated without internet connection.</p> <p>&quot;By partnering with CADENAS PARTsolutions, SAE is able to bring the aerospace industry a solution to reduce design cycle times and ensure quality and consistency, thereby generating savings in both time and money,&quot; says Michael Thompson, Director of Aerospace - Electronic Publications.</p> </div> http://hydraulicspneumatics.com/other-components/partnership-delivers-aerospace-standard-cad-model-catalog#comments Technologies Other Components Thu, 16 Jun 2016 14:15:00 +0000 38851 at http://hydraulicspneumatics.com <p>PARTsolutions Strategic Parts Management, a behind-the-firewall application, enables engineers to&nbsp;download parts from more than 600 digital catalogs of manufacturer-certified components. It now includes SAE MOBILUS&mdash;a catalog containing SAE Aerospace Standard 3D models.</p> June 2016 http://hydraulicspneumatics.com/node/38861 <div class="node-body magazine_issue-body"></div> <fieldset class="fieldgroup group-mag-teasers"> <div class="field-mag-teaser"> <a href="/cylinders-actuators/stick-slip-happens-how">Stick-Slip Happens, But How? </a> <a href="/hydraulic-valves/gain-control-flow">Gain Control of the Flow</a> <a href="/blog/fluid-power-gives-robot-arms-all-right-moves">Fluid Power Gives Robot Arms All the Right Moves</a> </div> </fieldset> <fieldset class="fieldgroup group-publication-info"><legend>Publication Info</legend> </fieldset> Thu, 16 Jun 2016 04:00:00 +0000 38861 at http://hydraulicspneumatics.com How To Select Hydraulic Connectors For Leak-Free Reliability http://hydraulicspneumatics.com/blog/how-select-hydraulic-connectors-leak-free-reliability <div class="node-body blog-body"><p>Hydraulic oil leaks are often considered to be an inherent characteristic of hydraulic machines. While this may have been true 30 years ago, advances in sealing technology and the development of reliable connection systems means that today, leak-free hydraulic plumbing is readily achievable.<br /> <br /> <strong>Reliable Connections</strong><br /> Leak-free reliability begins at the design stage, when the type of hydraulic fitting is selected for port, tube-end and hose-end connections.<br /> <br /> Ports - Connectors that incorporate an elastomeric seal such as UN O-ring, BSPP and SAE 4-bolt flange offer the highest seal reliability. NPT and BSPT are the least reliable type of connector for high-pressure hydraulic systems because the tapered thread itself provides a leak path. The threads are deformed when tightened and as a result, any subsequent loosening or tightening increases the potential for leaks. In existing systems, tapered thread connections should be replaced with UN O-ring or BSPP for leak-free reliability.<br /> <br /> Tube and Hose Ends - ORFS tube and hose end connections feature the high seal reliability afforded by an elastomeric seal but, due to its cost, ORFS is not as widely used as compression fittings and JIC 37-degree flare.<br /> <br /> Flared connections have gained widespread acceptance due to their simplicity and low cost. However, the metal-to-metal seal of the flare means that a permanent, leak-free joint is not always achieved, particularly in the case of tube-end connections.<br /> <br /> Leaking flare joints can be eliminated using a purpose-built seal developed by Flaretite. The Flaretite seal is a stainless steel stamping shaped like a JIC nose, with concentric ribs that contain pre-applied sealant. When tightened, the ribs crush between the two faces of the joint, eliminating any misalignment and surface imperfections. The combination of the crush on the ribs and the sealant ensure that a leak-free joint is achieved.<br /> <br /> <strong>Incorrect Torque</strong><br /> A common cause of leaks from flare joints is incorrect torque. Insufficient torque results in inadequate seat contact, while excessive torque can result in damage to the tube and fitting through cold working.<br /> <br /> <strong>Vibration</strong><br /> Vibration can stress plumbing, affecting hydraulic connector torque and causing fatigue. Tube is more susceptible than hose. If vibration is excessive, the root cause should be addressed. Ensure all conductors are adequately supported and if necessary, replace problematic tubes with hose.<br /> <br /> <strong>Seal Damage</strong><br /> Having outlined the benefits of hydraulic fittings that incorporate an elastomeric seal, it is important to note that their reliability is contingent on fluid temperature being maintained within acceptable limits. A single over-temperature event of sufficient magnitude can damage all the seals in a hydraulic system, resulting in numerous leaks.<br /> <br /> <strong>Conclusion</strong><br /> A leak-free hydraulic system should be considered the norm for modern hydraulic machines - not the exception. This means the improper selection, installation and maintenance of hydraulic plumbing can be a costly mistake. And to discover six other costly mistakes you want to be sure to avoid with your hydraulic equipment, <a href="http://www.hydraulicsupermarket.com/track?p=handp&amp;w=smr"><strong>get &quot;Six Costly Mistakes Most Hydraulics Users Make... And How You Can Avoid Them!&quot; available for FREE download here</strong></a>.</p> </div> http://hydraulicspneumatics.com/blog/how-select-hydraulic-connectors-leak-free-reliability#comments Hydraulics At Work Tue, 14 Jun 2016 01:23:00 +0000 38801 at http://hydraulicspneumatics.com Cavitación en un sistema hidráulico http://hydraulicspneumatics.com/blog/cavitaci-n-en-un-sistema-hidr-ulico <div class="node-body blog-body"><p class="rtejustify"><strong>Cavitaci&oacute;n en sistemas hidr&aacute;ulicos</strong></p> <p class="rtejustify"><img alt="" src="http://hydraulicspneumatics.com/site-files/hydraulicspneumatics.com/files/uploads/2015/09/20150626_154044.gif" style="width: 350px; height: 197px; margin: 10px; float: right;" title="Figura 1: daños por cavitación en una bomba de engranajes externos. Se pueden observar en el área de alta presión donde los engranajes comprimen el fluido" />El fen&oacute;meno de la cavitaci&oacute;n, definido de manera sencilla como la formaci&oacute;n de burbujas en un l&iacute;quido, puede tener efectos negativos en una bomba hidr&aacute;ulica. En un sistema hidr&aacute;ulico mal dise&ntilde;ado, se puede generar un vac&iacute;o que permite que el aire encerrado en el flu&iacute;do sea extra&iacute;do, form&aacute;ndose as&iacute; peque&ntilde;as burbujas.</p> <p class="rtejustify">&nbsp;Una variedad de factores en el sistema podr&iacute;an generar ese vac&iacute;o. Cuando el fluido entra a la bomba y es comprimido, las peque&ntilde;as burbujas implosionan a nivel molecular. Cada una de &eacute;stas implosiones son m&aacute;s fuertes de lo que pensamos y pueden llegar a remover material interno de la bomba hasta impedir el funcionamiento apropiado de la misma. La cavitaci&oacute;n puede destruir equipo nuevo en minutos, dejando signos de da&ntilde;os f&iacute;sicos incluyendo patrones espec&iacute;ficos. El proceso de destrucci&oacute;n por cavitaci&oacute;n tiene adem&aacute;s un sonido caracter&iacute;stico similar al de un gru&ntilde;ido.</p> <p class="rtejustify">Las buenas noticias son que &eacute;ste fen&oacute;meno no tiene que ser un problema com&uacute;n en sistemas hidr&aacute;ulicos. Algunas fallas de dise&ntilde;o son las responsables de causar cavitaci&oacute;n: configuraci&oacute;n err&oacute;nea de l&iacute;neas de succi&oacute;n de bombas y la utilizaci&oacute;n de filtros o mallas de succi&oacute;n. Para prevenir &eacute;stas causas de cavitaci&oacute;n y asegurarnos que dise&ntilde;amos un sistema con una vida &uacute;til larga y productiva, siete elementos deben ser correctamente ejecutados:</p> <ol> <li class="rtejustify">Dise&ntilde;ar el tanque correctamente,</li> <li class="rtejustify">Utilizar un filtro de respiradero en el tanque,</li> <li class="rtejustify">Instalar l&iacute;neas de succi&oacute;n dimensionadas y configuradas correctamente,</li> <li class="rtejustify">Remover filtraci&oacute;n en la l&iacute;nea de succi&oacute;n,</li> <li class="rtejustify">Utilizar una bomba correctamente dimensionada,</li> <li class="rtejustify">Mantener una temperatura adecuada del fluido,</li> <li class="rtejustify">Utilizar una succi&oacute;n con presi&oacute;n positiva.</li> </ol> <p class="rtejustify"><strong>&iquest;Qu&eacute; da inicio a la cavitaci&oacute;n?</strong></p> <p class="rtejustify"><img alt="" src="http://hydraulicspneumatics.com/site-files/hydraulicspneumatics.com/files/uploads/2015/09/20150626_153618.gif" style="width: 350px; height: 197px; margin: 10px; float: right;" title="Figura 2: Daños por cavitación en el plato de control de una bomba de pistones axiales. Note como empieza al final de la zona de transición y se propaga a través de la zona de alta presión." />Como se mencion&oacute; anteriormente, las causas principales de la cavitaci&oacute;n en un sistema hidr&aacute;ulico son la configuraci&oacute;n incorrecta de l&iacute;neas de succi&oacute;n y el uso de filtros o mallas en &eacute;sta. Cuando configuramos una l&iacute;nea de succi&oacute;n, se debe hacer minimizando la ca&iacute;da de presi&oacute;n a la entrada de la bomba. La estrategia principal para lograr esto es de especificar mangueras lo m&aacute;s cortas posible y el menor n&uacute;mero de conexiones a la entrada. A la hora de dise&ntilde;ar circuitos hidr&aacute;ulicos, los ingenieros generalmente se olvidan de considerar el largo de las mangueras requeridas para conectar la bomba a tanque. Mientras m&aacute;s largo es el camino que tiene que recorrer el fluido hidr&aacute;ulico, mayor ser&aacute; la caida de presion. Adicionalmente a esto, cada conector que utilizamos en una manguera le agrega p&eacute;rdidas a la l&iacute;nea, aumentando as&iacute; el riesgo de cavitaci&oacute;n.</p> <p class="rtejustify">Adem&aacute;s de configurar err&oacute;neamente las l&iacute;neas de succi&oacute;n de las bombas, la utilizaci&oacute;n de filtros o mallas de succi&oacute;n pueden ser una causa de la cavitaci&oacute;n. Estos filtros son frecuentemente instalados por debajo del tanque, por lo que rara vez se les hace servicio debido a lo inconveniente de su ubicaci&oacute;n. Con &eacute;sta configuraci&oacute;n, el tanque completo debe ser drenado y desarmado para alcanzar el filtro, por lo que la tarea es generalmente olvidada. A medida que el filtro se llena de part&iacute;culas, restringir&aacute; el flujo de aceite a la bomba y se producir&aacute; la cavitaci&oacute;n.</p> <p class="rtejustify">Estos casos de cavitaci&oacute;n pueden ser prevenidos utilizando una serie de pr&aacute;cticas correctas basadas en las necesidades espec&iacute;ficas y funciones de un sistema hidr&aacute;ulico. Muchos sistemas son &uacute;nicos, por lo que se requiere de un ingeniero con experiencia para que se cerciore de la correcta instalaci&oacute;n y mantenimiento del sistema hidr&aacute;ulico.</p> <p class="rtejustify"><strong>Dise&ntilde;o correcto de un reservorio</strong></p> <p class="rtejustify">Las burbujas de aire en el fluido hidr&aacute;ulico se originan en el reservorio. Aceite nuevo que sea introducido en el mismo puede causar un flujo turbulento, lo que revuelve el aceite e intruduce aire en el mismo, cosa que pueda conllevar a la cavitaci&oacute;n. Un tanque correctamente dise&ntilde;ado prevendr&aacute; este problema.</p> <p class="rtejustify">La mejor manera de prevenir flujo turbulento cuando retorna aceite al tanque es utilizando tubos de llenado, o aqu&eacute;llos que se extienden hasta el fondo del tanque, de manera que el fluido de retorno ingrese por debajo del existente. Adem&aacute;s de esto, el tanque deber&iacute;a contar con deflectores que dividen el aceite caliente que retorna a tanque y el que se encuentra listo para ingresar a la bomba. Es importante que el acete repose lo suficiente en el tanque de manera que los solidos precipiten al fondo y las burbujas de aire suban a la superficie, de manera que cualquier fluido retirado del mismo este libre de estos elementos.</p> <p class="rtejustify">El tamano del tanque y la cantidad de fluido que debe reposar antes de ser extraido depende del caudal.&nbsp; La recomendaci&oacute;n es la de considerar una relaci&oacute;n de 4:1 entre el volumen del tanque y el caudal. Esto garantiza que la bomba reciba aceite limpio y que &eacute;ste repose lo suficiente para las impurezas se limpien y se disipe el aire.</p> <p class="rtejustify"><strong>Utilice un filtro de respiradero</strong></p> <p class="rtejustify"><img alt="" src="http://hydraulicspneumatics.com/site-files/hydraulicspneumatics.com/files/uploads/2015/09/DSCF1347.gif" style="width: 350px; height: 262px; margin: 10px; float: right;" title="Figura 3: Esta imagen muestra el inicio del daño causado por cavitación en un plato de control de una bomba de pistones axiales." />​Ademas de disenar el tanque correctamente, la inclusi&oacute;n de los accesorios correctos es importante para asegurar la funcionabilidad. El filtro de respiradero es quizas el accesorio mas importante para mantener las condiciones ideales del fluido hidraulico en el tanque.</p> <p class="rtejustify">Cuando la bomba succiona fluido del tanque y una cantidad igual no reotrna al mismo, el nivel baja. Para regular la presi&oacute;n y evitar que se forme un vac&iacute;o, se debe introducir aire al tanque para que ocupe el volumen adicional creado al removerse el fluido. Un filtro de respiradero desempe&ntilde;a esta funcion que ayuda a evitar la cavitacion.</p> <p class="rtejustify"><strong>Incluya l&iacute;neas de succi&oacute;n apropiadas</strong></p> <p class="rtejustify">Como ya sabemos, el dise&ntilde;o y configuraci&oacute;n incorrecta de l&iacute;neas de succi&oacute;n es la causa principal de la cavitaci&oacute;n en un sistema hidr&aacute;ulico. Por esto, es crucial que apliquemos pr&aacute;cticas de dise&ntilde;o apropiadas en el momento de configurar las mismas: dimensionamiento adecuado, minimizar la presencia de conectores en la l&iacute;nea y dimensionar la v&aacute;lvula de bola adecuada para manejar el caudal requerido.</p> <p class="rtejustify">La l&iacute;nea debe ser lo suficientemente grande como para que fluya la cantidad de l&iacute;quido requerida. Como la bomba debe contar con un suministro constante de aceite, resulta obvio que una l&iacute;nea sub-dimensionada no permita que esto ocurra. Las especificaciones precisas en cuanto a longitud y di&aacute;metro de l&iacute;neas de succi&oacute;n no pueden ser determinadas a la ligera &ndash; se requiere de un ingeniero con el conocimiento suficiente del proceso en cuesti&oacute;n para tomar la decisi&oacute;n correcta.</p> <p class="rtejustify">Otra pr&aacute;ctica a considerar en la configuraci&oacute;n de l&iacute;neas de succi&oacute;n es la de incluir un seguro en la v&aacute;lvula de bola que prevenga el cierre accidental de la misma durante la operaci&oacute;n de la bomba, ya que en caso de que esto ocurriese, habr&iacute;an efectos perjudiciales en el sistema.</p> <p class="rtejustify"><strong>Elimine Filtros de Succi&oacute;n</strong></p> <p class="rtejustify">Los sistemas de filtraci&oacute;n ubicados dentro del tanque son inc&oacute;modos y dif&iacute;ciles de mantener, muchas veces resultando esto en l&iacute;neas tapadas que limitan el flujo de aceita hacia la bomba y generan da&ntilde;os severos. Por esto recomendamos dejar las l&iacute;neas de succi&oacute;n sin filtro. Se puede compensar la falta con filtraci&oacute;n adicional en el circuito hidr&aacute;ulico, por ejemplo: el aceite puede ser filtrando al entrar en el reservorio en lugar de hacerlo cuando salga del mismo. Tambi&eacute;n se puede utilizar un sistema de filtraci&oacute;n fuera de l&iacute;nea (ri&ntilde;oneras) de manera de retirar el aceite del tanque, filtrarlo, y reinyectarlo antes de ser extra&iacute;do por la bomba hidr&aacute;ulica. Estas soluciones facilitan el mantenimiento y reducen las posibilidades de falla.</p> <p class="rtejustify"><strong>Dimensione correctamente la bomba</strong></p> <p class="rtejustify">Un aspecto clave en sistemas hidr&aacute;ulicos es el dimensionamiento correcto de la bomba. De nuevo, la decisi&oacute;n debe ser hecha por un ingeniero con experiencia que entienda el proceso en su totalidad. El tama&ntilde;o de una bomba puede ser determinado incorporando un n&uacute;mero de variables en una ecuaci&oacute;n est&aacute;ndar, mientras se consideran aspectos &uacute;nicos de la aplicaci&oacute;n.</p> <p class="rtejustify"><strong>Mantenga la temperatura del fluido apropiada</strong></p> <p class="rtejustify">Otro elemento clave en un sistema hidr&aacute;ulico es el de mantener la temperatura del fluido a niveles apropiados. Si el mismo se enfr&iacute;a mucho, se vuelve muy viscoso, lo que aumentar&iacute;a la ca&iacute;da de presi&oacute;n en las l&iacute;neas y eventualmente podr&iacute;a desencadenar en cavitaci&oacute;n en la bomba. Por otro lado, un fluido sobrecalentado perder&iacute;a mucha viscosidad, lo que comprometer&iacute;a su capacidad de lubricaci&oacute;n de la bomba.</p> <p class="rtejustify">Para regular la temperatura del fluido, intercambiadores de calor pueden ser colocados en el tanque para mantener el fluido a la temperatura ideal.</p> <p class="rtejustify"><strong>Proporcione presi&oacute;n positiva a la succi&oacute;n</strong></p> <p class="rtejustify">La mayor&iacute;a de los sistemas utilizan un dise&ntilde;o de succi&oacute;n con presi&oacute;n positiva, lo que significa que la bomba est&aacute; ubicada por debajo del nivel del aceite. El mismo sale del reservorio por encima de la bomba, lo que implica que se aprovecha la gravedad para generar presi&oacute;n a la succi&oacute;n.</p> <p class="rtejustify">La alternativa a &eacute;ste arreglo es una succi&oacute;n regular, en la que la bomba se ubica por encima del tanque. Esta configuraci&oacute;n es utilizada para ahorrar espacio en un sistema con una huella limitada, pero resulta en varias limitaciones: la bomba tiene que trabajar extra en generar el vac&iacute;o para extraer el aceite del tanque contra la gravedad, esto inherentemente implica una restricci&oacute;n en la succi&oacute;n. Adem&aacute;s existen muchas bombas que no funcionan a nivel &oacute;ptimo cuando no cuentan con succi&oacute;n positiva. En estos casos se puede utilizar una bomba de pre-carga en la l&iacute;nea de succi&oacute;n.</p> <p class="rtejustify">Si cada uno de estos elementos son considerados al momento de dise&ntilde;ar un sistema hidr&aacute;ulico, los riesgos de da&ntilde;ar o destruir la bomba hidr&aacute;ulica podr&iacute;an reducirse considerablemente.</p> <p class="rtejustify"><em>Ricardo Sol&oacute;rzano&nbsp;se desempe&ntilde;a como director general de EEM Technologies Corp., proveedor de soluciones en hidr&aacute;ulica, neum&aacute;tica y automatizaci&oacute;n industrial para los mercados Latino Americanos. Para mayor informaci&oacute;n puede contactarlo al: +1(855)462-7633, <a href="mailto:info@eemtechnologies.com">info@eemtechnologies.com</a>, o www.eemtechnologies.com.</em></p> <p class="rtejustify">&nbsp;</p> <p class="rtejustify">&nbsp;</p> </div> http://hydraulicspneumatics.com/blog/cavitaci-n-en-un-sistema-hidr-ulico#comments Hydraulics System Design H&amp;P en tu idioma! Mon, 13 Jun 2016 14:22:00 +0000 38791 at http://hydraulicspneumatics.com Position Sensor Approved for Hazardous Areas http://hydraulicspneumatics.com/controls-instrumentation/position-sensor-approved-hazardous-areas <div class="node-body article-body"><p>MTS Sensors, a division of MTS Systems Corp., announced that its Temposonics T-Series sensors are now certified to NEC and CEC standards 500, 505, and 506. Both NEC and CEC certifications are used in U.S. and Canada to ensure operation of equipment in potentially hazardous conditions. The T-Series linear-position sensors, which already carry the ATEX and IECEx approvals used by other countries, are ATEX, IECEx, NEC, and CEC hazardous-area certified for use in Class I, II, and III in Divisions 1, and 2, for Groups A through G, and Zone 0/1, 21 and 22.&nbsp;</p> <div class="related-content"> <div class="related-label">Related</div> <p><a href="http://hydraulicspneumatics.com/other-components/forklift-scale-leverages-hydraulic-pressure-sensor-weigh-loads ">Forklift Scale Leverages Hydraulic-Pressure Sensor to Weigh Loads</a></p> <p><a href="http://hydraulicspneumatics.com/cylinders-amp-actuators/eaton-hydraulics-names-price-engineering-first-certified-cylinder-service-ce ">Eaton Hydraulics names Price Engineering as first Certified Cylinder Service Center</a></p> <p><a href="http://hydraulicspneumatics.com/controls-amp-instrumentation/m-series-model-mh-sensor-mts-systems-corp">M-Series Model MH Sensor from MTS Systems Corp.</a></p> </div> <p>The T-Series is available in standard and SIL2 versions, which follow the Safety Integrity Level standard IEC 61508. It caters to the growing demand for hazardous-area and functional-safety solutions sought by engineers in the power-generation, oil-processing, and chemical-processing industries.</p> <p>By integrating the company&rsquo;s proprietary Temposonics magnetostrictive technology, the sensors feature non-contact position-measuring capabilities that ultimately eliminate moving parts for a longer lifespan and minimization of maintenance, plus there&rsquo;s no need for recalibration. The sensors are resilient to vibrations, shock, and extreme pressures.&nbsp;</p> </div> http://hydraulicspneumatics.com/controls-instrumentation/position-sensor-approved-hazardous-areas#comments Food & Beverage Controls & Instrumentation News Mon, 13 Jun 2016 13:42:00 +0000 38781 at http://hydraulicspneumatics.com A Snapshot of Social Media http://hydraulicspneumatics.com/blog/snapshot-social-media <div class="node-body blog-body"><p>Back about 25 years ago, many of us relied on America Online to access the internet and communicate with others. Those who were more computer-savvy used CompuServe or some other provider because they felt AOL was too restrictive.</p> <div class="related-content"> <div class="related-label">Related</div> <p><a href="http://hydraulicspneumatics.com/events/editor-returning-most-basic-social-media">From the Editor: Returning to the Most-Basic Social Media</a></p> <p><a href="http://ydraulicspneumatics.com/other-technologies/new-media-starting-blend-together">New Media Starting to Blend Together</a></p> <p><a href="http://hydraulicspneumatics.com/technologies/social-media-rescue">Social Media to the Rescue</a></p> </div> <p>AOL evolved with the times and brought us instant messaging. Wasn&rsquo;t that cool? But as new concepts emerged, AOL was nearly left behind. I say nearly, because it&rsquo;s still around. Then came MySpace.com, which was dedicated to social media. However, I don&rsquo;t think the term &ldquo;social media&rdquo; was even used back then. MySpace became the rage with the younger crowd, and adults eventually were attracted to Facebook. I even remember friends grumbling that kids shouldn&rsquo;t be on Facebook, that they should stay on MySpace.</p> <p>Social media was not widely used for business back then. In fact, most companies did not host their own websites. Company officials knew they needed websites, but they didn&rsquo;t have the resources to make it happen. Instead, they contracted with a web hosting company. As a result, most companies did not have a url like &quot;www.abcco.com.&quot; Instead, it was probably <a href="http://www.thomasnet.com" target="_blank">www.thomasnet.com</a>/abcco or <a href="http://www.industrynet.com" target="_blank">www.industrynet.com</a>/abcco&mdash;at least those are two major players I remember.</p> <p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2015/03/socialmedia_web.jpg" style="width: 595px; height: 595px;" /></p> <p>Now, of course, people have several choices for social media. LinkedIn seems to be the preferred vehicle for networking among professionals, and our <em>Hydraulics &amp; Pneumatics</em> LinkedIn group has more than 18,000 members (to be exact, 18,027 as of this writing).</p> <p>That&rsquo;s where we are today, this moment in time. But where will we be 10 or 15 years from now? The answer may depend on where the Internet of Things and Industry 4.0 take us. It seems as if the questions about these topics vastly outnumber the answers.</p> <p>But if you have any interest in the Internet of Things&mdash;or its close cousin, Industry 4.0&mdash;I recommend you visit the <a href="http://www.ioti.com/" target="_blank">Internet of Things Institute</a>. You might even find the answers to a few questions there.</p> <p><em>Looking for parts? Go to <a href="http://sourceesb.com/" target="_blank">SourceESB</a>.</em></p> </div> http://hydraulicspneumatics.com/blog/snapshot-social-media#comments Community The Hitch Post Mon, 13 Jun 2016 13:31:00 +0000 38771 at http://hydraulicspneumatics.com Premature Failures and What to Do About Them http://hydraulicspneumatics.com/maintenance/premature-failures-and-what-do-about-them <div class="field-deck"> Despite all our best efforts to practice good preventive and proactive maintenance, premature component failures still occur—and repair costs may still lie with the component supplier. </div> <div class="node-body article-body"><table border="0" cellpadding="0" cellspacing="0" width="570"> <tbody> <tr> <td width="41"><img src="http://insidepenton.com/electronic_design/adobe-pdf-logo-tiny.png" /></td> <td style="padding-left: 0px;" width="459"><a href="/datasheet/premature-failures-and-what-do-about-them-pdf-download-1#node-38761">Download this article in .PDF format</a><br /> This file type includes high-resolution graphics and schematics when applicable.</td> </tr> </tbody> </table> <p>When it comes to ensuring the reliability of hydraulic components and systems, I cannot overemphasize the importance of:</p> <p>&bull; proactive rather than reactive maintenance;</p> <p>&bull; getting the fundamentals right&mdash;using the right oil and keeping it cool, dry, and clean;&nbsp;</p> <p>&bull; configuring your hydraulic equipment for the maintenance and reliability outcomes you desire; and</p> <p>&bull; using checklists to reveal hidden failures and prevent maintenance procedure failures that result in infant mortality of hydraulic components.</p> <div class="related-content"> <div class="related-label">Related</div> <p><a href="http://hydraulicspneumatics.com/blog/bitter-sweet-nature-proactive-maintenance">The Bitter-Sweet Nature of Proactive Maintenance</a></p> <p><a href="http://hydraulicspneumatics.com/blog/hydraulic-maintenance-dilemma-not-deciding-has-consequences">The Hydraulic Maintenance Dilemma: Not Deciding Has Consequences</a></p> <p><a href="http://hydraulicspneumatics.com/blog/predictive-hydraulics-maintenance-101">Predictive Hydraulics Maintenance 101</a></p> </div> <p>The reality, though, is even if you do all these things right, in-service failures can still happen. And when a hydraulic component does fail prematurely, the first question usually asked is: who pays? Typically, it is the &ldquo;negligent&rdquo; party. But determining who that is&mdash;and then convincing everyone involved&mdash;is always easier said than done.</p> <p><strong>Factory Fresh or Rebuilt?</strong></p> <p>If the failed hydraulic component is a new one from the factory, a shadow is often cast over the way it was installed and commissioned and the conditions it operated in. This includes oil cleanliness, oil temperature and viscosity, operating pressure, circuit design, and possible operator abuse. This is not to say manufacturing defects don&rsquo;t occur. They can and do happen. But a new hydraulic component is usually given the benefit of any doubt&mdash;in the first instance, at least.</p> <p>If, on the other hand, the failed hydraulic component is a rebuilt unit, not only is the way it was installed, commissioned, and the conditions it operated in called into question, so, too, is the quality of the rebuild.</p> <p>Regardless of whether the component is new or rebuilt, when a premature failure occurs, it is essential that a proper and thorough analysis be conducted to determine the cause. In fact, failure analysis is an important proactive measure and an essential element of any preventative maintenance program. The logic for this is simple: If a component fails prematurely, and the cause of the failure is not identified and rectified immediately, then the replacement component is likely to suffer a similar fate.</p> <p><strong>Expertise in Question</strong></p> <p>Conducting failure analysis on hydraulic components is a highly specialized task. It requires a solid understanding of hydraulic circuits, the construction of hydraulic components, and their modes of failure. This means the task usually becomes the responsibility of the company who either manufactured or rebuilt the failed component. Understandably, this results in an absence of independence from the machine owner&rsquo;s perspective.</p> <p>I&rsquo;ve been involved in many warranty claims&mdash;on both sides of the fence and in the middle&mdash;and this is what I have learned:</p> <p>1. Failure analysis is not always conclusive.</p> <p>2. If a repairer has made a mistake, he usually knows. But this doesn&rsquo;t mean he&rsquo;ll always admit it.</p> <p>3. A lot of people get involved in failure analysis and warranty claims. But they don&rsquo;t have the necessary expertise&mdash;and they shouldn&rsquo;t.</p> <p>4. Although contamination and cavitation can and do cause premature failures, they are incorrectly offered as explanation for a lot of hydraulic component failures.</p> <p>As an example of points 3 and 4, some years ago I tried to get warranty on a new pump I had supplied for a project. It was a piston pump that started separating (the cylinder barrel was losing contact with the valve plate) in less than 100 hours. My own investigation showed that the valve plate was &ldquo;hung up&rdquo; on its dowel pin. This meant it was not sitting flat against the head or the cylinder barrel. Without question, this was an assembly fault at the factory.</p> <p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2015/03/Fig-1-lens.jpg" style="width: 595px; height: 560px;" title="Scoring of this piston pump valve plate was caused by cylinder barrel separation." /></p> <p>The pump manufacturer&rsquo;s salesman came along to examine what I&rsquo;d found, and I explained everything in detail. The separation of the barrel from the valve plate resulted in scoring of their mating surfaces. The photos above and below this paragraph show typical damage of this nature. As soon as the manufacturer&rsquo;s representative saw this, he was adamant the failure resulted from contamination, and there was no convincing him otherwise.</p> <p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2015/03/Fig-2-barrel-P2.jpg" style="width: 595px; height: 572px;" title="Marks on a piston pump’s cylinder barrel show uneven contact with its valve plate. This damage was caused by the pump’s valve plate hanging up on its dowel pin. Therefore, it did not sit flat against the head. In this case, the damage resulted from an assembly error at the manufacturer." /></p> <p>Such an outcome is frustrating to say the least. You do have to forgive hydraulic equipment owners from wondering if this sort of behavior is an intentional tactic by some component manufacturers to avoid all warranty claims.</p> <p><strong>Warranty Issues</strong></p> <p>Of course, the warranty on a new or rebuilt hydraulic component is not unconditional. Nor should it be. If you&rsquo;ve ever read the warranty conditions for a hydraulic component, you would know that a number of circumstances can result in rejection of a warranty claim, if any is deemed to have caused the component to fail.</p> <p>These include:</p> <p>&bull; improper storage or handling;</p> <p>&bull; interference or tampering with the component while in storage, such as the removal of parts&mdash;even if these parts are replaced prior to the unit being put into service;</p> <p>&bull; failure to follow proper commissioning or start-up procedures;</p> <p>&bull; incorrect setting or adjustment;</p> <p>&bull; contaminated oil;</p> <p>&bull; incorrect oil viscosity;</p> <p>&bull; damage caused by incorrect adjustment of the machine&rsquo;s hydraulic or electronic system;</p> <p>&bull; damage caused by faulty components in the machine&rsquo;s hydraulic or electronic system;</p> <p>&bull; improper machine operation.</p> <p>Therefore, many things must be done to ensure that the life of a replacement hydraulic component&mdash;whether new or rebuilt&mdash;is not compromised during its storage, installation, commissioning, and, ultimately, its operation.</p> <p>But who&rsquo;s responsible for ensuring that what needs to be done actually gets done? Generally speaking, it&rsquo;s the party that installs the component on the machine. If the guy who installs the component on the machine doesn&rsquo;t know what he&rsquo;s doing, is that the component supplier&rsquo;s problem? It is if the installer works for the component supplier.</p> <p><strong>Flushing the System after Repair</strong></p> <p>This is why I advise machine owners whose primary concern is not voiding the warranty on a replacement hydraulic component gets the component supplier to install and commission it. This gives the supplier a free hand to carry out any related work deemed necessary&mdash;within reason, of course. An example might be flushing the hydraulic system to prevent the possibility of consequential damage caused by debris from the previous failure (if applicable).</p> <p>Although flushing will involve some additional cost, it can be well worth the expense. If a warranty claim occurs, and the failure is attributed to incorrect installation, commissioning, or incorrect adjustment of the hydraulic system&rsquo;s settings, responsibility for the failure falls back on the supplier of the component. That&rsquo;s because it was the supplier&rsquo;s responsibility to get all these things right.</p> <p>And if time pressures won&rsquo;t allow the job to be done right (there&rsquo;s no time to flush the system to remove all debris from a previous catastrophic failure), then that&rsquo;s not the component supplier&rsquo;s fault. It&rsquo;s fair and reasonable, then, that any risk of premature failure from such omission transfers to the machine owner.</p> <p>Similarly, if it&rsquo;s not practical for the supplier to install the component, then the onus falls on the machine owner&rsquo;s technician to know what he&rsquo;s doing and/or seek the necessary advice. At the very least, he should request a detailed commissioning procedure and checklist from the component&rsquo;s supplier. This procedure should be carefully followed and properly documented, so that it can be referred to in the event of a warranty claim.</p> <p>If a warranty claim does occur, and the failure is attributed to incorrect commissioning, then at least some of the responsibility for the failure falls back on the component supplier if it can be demonstrated that the supplied commissioning procedure was followed.</p> <p>Smart hydraulic component suppliers take the lead in this issue by advising and warning their customers of the potential pitfalls&mdash;for example, the attachment of an oil-resistant warning tag to each component supplied, which outlines the essential steps to be followed during commissioning. However, a tag cannot be expected to cover all situations; therefore, it is not a substitute for proper training and experience.</p> <p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2015/03/Fig-3-Commissioning-tag.gif" style="width: 400px; height: 571px; float: left;" title="Here is a sample of oil-resistant commissioning tag that should be attached to a hydraulic pump." /></p> <p>And as already stated, contamination is an all-too-common excuse for rejecting warranty claims. So when practical, it&rsquo;s also wise to take an oil sample prior to replacing hydraulic components. This establishes a reference cleanliness level for the fluid in the system if a premature failure occurs and contamination is cited as a basis for rejecting the claim.</p> <p>In summary, premature failures and the warranty claims that follow almost always result in win/lose outcomes. So my best advice, regardless of whether you&rsquo;re a supplier or repairer of hydraulic components, or a machine owner, is take all reasonable steps to ensure you don&rsquo;t find yourself in a warranty situation in the first place. In other words, doing everything you possibly can to proactively avoid premature failures. And this means acting on the advice contained in <em>The Hydraulic Maintenance Handbook</em>!</p> <p><em>Brendan Casey is hydraulics specialist with an MBA and more than 25 years experience in the design, maintenance, and repair of mobile and industrial hydraulic equipment. He is the founder of <a href="http://www.hydraulicsupermarket.com" target="_blank">HydraulicSupermarket.com</a>, the author of several books and an enewsletter covering hydraulics technology, and he writes the Hydraulics at Work blog on our website. For information on his resources, visit <a href="http://www.hydraulicsupermarket.com/" target="_blank">www.hydraulicsupermarket.com</a>. To order his book, The Hydraulic Maintenance Handbook, go to <a href="http://bit.ly/HP0616THMH" target="_blank">bit.ly/HP0616THMH</a>.</em></p> <p><em>Looking for parts? Go to <a href="http://sourceesb.com/" target="_blank">SourceESB</a>.</em></p> <table border="0" cellpadding="0" cellspacing="0" width="570"> <tbody> <tr> <td width="41"><img src="http://insidepenton.com/electronic_design/adobe-pdf-logo-tiny.png" /></td> <td style="padding-left: 0px;" width="459"><a href="/datasheet/premature-failures-and-what-do-about-them-pdf-download-1#node-38761">Download this article in .PDF format</a><br /> This file type includes high-resolution graphics and schematics when applicable.</td> </tr> </tbody> </table> </div> http://hydraulicspneumatics.com/maintenance/premature-failures-and-what-do-about-them#comments Maintenance Fri, 10 Jun 2016 18:40:00 +0000 38731 at http://hydraulicspneumatics.com New Valve Technologies Improve Load- Sensing Systems http://hydraulicspneumatics.com/hydraulic-valves/new-valve-technologies-improve-load-sensing-systems <div class="field-deck"> Sponsored by Eaton </div> <div class="node-body article-body"><p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/05/Eaton_logo196x65.gif" style="width: 180px; height: 60px; float: right;" />The ability for a hydraulic system to provide variable pressure and variable flow has many advantages, not the least of which is energy efficiency&mdash; yet typical open-center and closed-center systems can&rsquo;t offer both simultaneously. Load-sensing systems, however, provide only the pressure and flow required by the hydraulic system.</p> <p>Download <em><strong>FAQs on New Valve Technologies Improve Load- Sensing Systems</strong></em> sponsored by <strong>Eaton </strong>to get the answers.</p> <script type="text/javascript"> document.write('\ <iframe style="height: 800px; width: 100%; border:0;” frameBorder="0" scrolling="no"\ src="http://pages.hydraulicspneumatics.com/HP_Digital_Eaton_ValveTechnologies_WP_JoR_060716?partnerref=' + getParameterByName("partnerref") + "&elq=" + getParameterByName("elq2") + "&code=" + getParameterByName("code") + "&PK=" + getParameterByName("PK") + "&PR=" + getParameterByName("PR") + '"></iframe>'); function getParameterByName(name) { var match = RegExp('[?&]' + name + '=([^&]*)').exec(window.location.search); if (match == null) return ""; return match && decodeURIComponent(match[1].replace(/\+/g, ' ')); } </script></div> http://hydraulicspneumatics.com/hydraulic-valves/new-valve-technologies-improve-load-sensing-systems#comments Design FAQs Hydraulic Valves Fri, 10 Jun 2016 16:29:00 +0000 38641 at http://hydraulicspneumatics.com Reader Offers Advice to Prevent Spline Wear http://hydraulicspneumatics.com/hydraulic-pumps-motors/reader-offers-advice-prevent-spline-wear <div class="field-byline"> Don Searles </div> <div class="node-body article-body"><table border="0" cellpadding="0" cellspacing="0" width="570"> <tbody> <tr> <td width="41"><img src="http://insidepenton.com/electronic_design/adobe-pdf-logo-tiny.png" /></td> <td style="padding-left: 0px;" width="459"><a href="/datasheet/reader-offers-advice-prevent-spline-wear-pdf-download-0">Download this article in .PDF format</a><br /> This file type includes high-resolution graphics and schematics when applicable.</td> </tr> </tbody> </table> <p>Until my retirement, my company, <a href="http://www.dredgingspecialists.com" target="_blank">Dredging Specialists</a>, designed, built, and operated hydraulic dredges, completing more than 150 projects in 22 states.</p> <p>The dredges we built were powered by diesel engines that drove hydraulic pumps. The hydraulic systems powered an underwater dredge pump, five winches, and other hydraulic actuators. A gear-drive box got bolted to the flywheel of the diesel engine to drive three hydraulic pumps. Typically, the two lower pumps were of axial-piston design and the upper one was a vane pump.</p> <div class="related-content"> <div class="related-label">Related</div> <p><a href="hydraulicspneumatics.com/hydraulic-pumps-motors/vane-type-hydraulic-motors-ideal-high-pressure-applications">Vane-Type Hydraulic Motors Ideal for High-Pressure Applications</a></p> <p><a href="http://hydraulicspneumatics.com/blog/how-avoid-dry-starting-hydraulic-pumps">How To Avoid &#39;Dry Starting&#39; Hydraulic Pumps</a></p> <p><a href="http://hydraulicspneumatics.com/hydraulic-pumps-motors/fundamentals-hydraulic-motors">Fundamentals of Hydraulic Motors</a></p> </div> <p>Each pump had a splined drive shaft that mated with internal splines in the output shafts of the gearbox. The shaft on the vane pump was smaller than those on the axial-piston pumps, so we had to install a splined adapter to mate the vane pump&rsquo;s input shaft with larger shaft of the gearbox.</p> <p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2015/03/Vane-pump-splines_web.jpg" style="width: 595px; height: 291px;" title="To prevent premature wear of a pump’s input shaft, apply Loctite to the splines on the pump shaft and to the internal splines of the adapter. Next, apply grease to the external splines of the adapter, install the adapter into the drive box, and then mount the pump to the drive box." /></p> <p>On the first dredge we built, the vane pump&rsquo;s shaft wore out very quickly. To solve the problem, we applied high-strength Loctite on both the small pump shaft and on the internal splines of the adapter.</p> <p>First, we applied Loctite to the splines on the pump. Next, we put Loctite on the inner spline of the adapter and applied grease to the outside. After sliding the adapter into the gearbox, we then installed the pump.</p> <p>This locked the vane-pump shaft to the adapter and prevented movement and wear between them. Even after thousands of hours of operation, the adapter was still locked on the vane-pump shaft, and the problem was solved.</p> <p><em>Submitted by Don Searles, who still provides expert witness and consulting services through Dredging Specialists. Visit <a href="http://www.dredgingspecialists.com" target="_blank">www.dredgingspecialists.com</a> for more information.</em></p> <p><em>Looking for parts? Go to <a href="http://sourceesb.com/" target="_blank">SourceESB</a>.</em></p> </div> http://hydraulicspneumatics.com/hydraulic-pumps-motors/reader-offers-advice-prevent-spline-wear#comments Marine & Offshore Hydraulic Pumps & Motors Fri, 10 Jun 2016 16:14:00 +0000 38691 at http://hydraulicspneumatics.com Ag Apps Are Just the Beginning http://hydraulicspneumatics.com/cylinders-actuators/ag-apps-are-just-beginning <div class="node-body article-body"><table border="0" cellpadding="0" cellspacing="0" width="570"> <tbody> <tr> <td width="41"><img src="http://insidepenton.com/electronic_design/adobe-pdf-logo-tiny.png" /></td> <td style="padding-left: 0px;" width="459"><a href="/datasheet/ag-apps-are-just-beginning-pdf-download">Download this article in .PDF format</a><br /> This file type includes high-resolution graphics and schematics when applicable.</td> </tr> </tbody> </table> <p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2015/03/ThinkstockPhotos-122477501_web.jpg" style="width: 595px; height: 397px;" title="Delavan’s tie-rod cylinders (below) can be used in agricultural equipment, such as this potato harvester, but their strength and reliability at working pressures to 3,000 psi also handle applications such as construction and forestry equipment." /></p> <p>As its name implies, <a href="http://www.delavanagpumps.com/" target="_blank">Delavan Ag Pumps</a>, Minneapolis, makes a variety of pumps for agricultural applications. However, Delavan also makes hydraulic cylinders, and not just for the ag market.</p> <div class="related-content"> <div class="related-label">Related</div> <p><a href="http://hydraulicspneumatics.com/cylinders-actuators/market-report-explores-hydraulic-cylinder-industry">Market Report Explores Hydraulic Cylinder Industry</a></p> <p><a href="http://hydraulicspneumatics.com/blog/straight-talk-about-bent-hydraulic-cylinder-rods">Straight Talk About Bent Hydraulic Cylinder Rods</a></p> <p><a href="http://hydraulicspneumatics.com/blog/how-test-hydraulic-cylinder">How To Test A Hydraulic Cylinder</a></p> </div> <p>Delavan&rsquo;s Series PML and PMH PowerMax hydraulic cylinders feature tie-rod construction and working pressure ratings of 2,500 psi and 3,000 psi, respectively. Both series come in standard bores of 2, 2&frac12;, 3, 3&frac12;, 4, and 5 in. with ductile iron rod clevis and heat-treated piston rods. Derek Proulx, product manager at Delavan, says all cylinders are tested to 1&frac12; times working pressure.</p> <p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2015/03/Delavan-cylinder_web.jpg" style="width: 595px; height: 313px;" /></p> <p>Delavan also offers two-stage hydraulic pumps, monoblock directional control valves, and flow-control valves. For more information, call Delavan Ag Pumps at (612) 333-3189, email <a href="mailto:delavansales@delavanagpumps.com">delavansales@delavanagpumps.com</a>, or visit <a href="http://www.delavanagpumps.com/" target="_blank">delavanagpumps.com</a>.</p> <p><em>Looking for parts? Go to <a href="http://sourceesb.com/" target="_blank">SourceESB</a>.</em></p> </div> http://hydraulicspneumatics.com/cylinders-actuators/ag-apps-are-just-beginning#comments Agricultural Cylinders & Actuators Thu, 09 Jun 2016 15:46:00 +0000 38671 at http://hydraulicspneumatics.com Hydraulic System Runs with Engine Shut Off http://hydraulicspneumatics.com/hydraulic-pumps-motors/hydraulic-system-runs-engine-shut <div class="node-body article-body"><p>Improving efficiency in both on- and off-highway vehicles and equipment ultimately leads to reduced fuel consumption. Designing more efficient hydraulic systems also helps cut fuel consumption, but this is only part of the equation. Even if a hydraulic system is 100% efficient, it still requires a gasoline or diesel engine to burn fuel in order to power the hydraulic power unit.</p> <p>Of course, we can&rsquo;t have a perfectly efficient hydraulic system, but companies have been able to find an alternative source of power for driving the hydraulic pump: an electric motor instead of an internal-combustion engine. This solution would be impractical for many applications. However, aerial work platforms present an excellent opportunity because the hydraulic system usually operates only when the vehicle is stationary.</p> <div class="related-content"> <div class="related-label">Related</div> <p><a href="http://hydraulicspneumatics.com/rail-truck-bus/work-truck-show-highlights-green-initiatives">Work Truck Show Highlights Green Initiatives</a></p> <p><a href="http://hydraulicspneumatics.com/machine-tools/machine-builder-unveils-green-hpu">Machine Builder Unveils Green HPU</a></p> <p><a href="http://hydraulicspneumatics.com/rail-truck-bus/so-just-what-work-truck">So Just What is a Work Truck?</a></p> </div> <p>When a work crew parks a vehicle and operates the hydraulic system, they can shut off the vehicle&rsquo;s motor but still operate the hydraulics. That&rsquo;s because the pump in a hydraulic power unit is driven by an electric motor, which draws power from a bank of rechargeable batteries. Depending on the system, the batteries may supply full power for an hour or longer.</p> <p>Although this is adequate for typical tasks, situations arise when more time is needed. In such cases, the system can be plugged into an external source of electrical power, or the vehicle&rsquo;s engine can be started to provide power while also recharging the batteries.</p> <p><strong>Award-Winning Solution</strong></p> <p>This type of hybrid hydraulic-electric system is one reason why Altec Industries, Birmingham, Ala., won the 2016 Green Award for its JEMS (Jobsite Energy Management System) hybrid-electric vehicles at the most recent Work Truck Show. The Green Award recognizes the product at the show that best improves work-truck fuel utilization, as determined by a panel of trade media editors and truck fleet managers.</p> <p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2015/03/Green-Award_Altec_web.jpg" style="width: 595px; height: 397px;" title="Altec Industries was presented the Green Award for its JEMS 4 Series Jobsite Energy Management System at the latest Work Truck Show. At left is William Callis, senior account manager for telecommunications at Altec, accepting the award from Steve Carey, executive director of NTEA. (Photo courtesy of NTEA)" /></p> <p>Altec&rsquo;s JEMS 4 Series is an updated energy-management system for utility work trucks. This integrated system uses stored electrical energy to power the aerial device, tools, accessories, exportable power, and engine-off cabin heating and cooling. It features lithium-ion energy and an on-demand electrified PTO (ePTO) for hydraulic power. This allows bucket units to operate quietly without the truck engine running, which is especially beneficial in urban areas.</p> <p>The compact system is equipped with Altec&rsquo;s Idle Mitigation System, which eliminates unnecessary idle time when the vehicle is parked, automatically transitioning from engine power to JEMS power. Mark Greer, market manager at Altec, says this reduces fuel consumption while minimizing emissions and engine maintenance. Ultimately, the integrated hybrid system reduces fuel consumption, cuts greenhouse gas emissions in half, and significantly reduces noise.</p> <p><strong>More Than Alternative Power</strong></p> <p>Eliminating or reducing fuel consumption to operate the hydraulic system is only one facet of Altec&rsquo;s JEMS 4 Series vehicles. The hydraulic system itself uses BioPure hydraulic oil, which provides the highest ASTM rating and is non-toxic to plants and animals.</p> <p>According to <a href="http://www.preferredindustrial.com" target="_blank">www.preferredindustrial.com</a>, BioPure is a biodegradable anti-wear hydraulic oil that meets or exceeds demands of both high- and low-pressure OEM hydraulic systems. It is intended as a replacement to mineral- and Canola-based hydraulic oils, where high performance, wide temperature range, high oxidation stability, low&nbsp;odor, and full biodegradability are required.</p> <p>The JEMS 4 Series also takes advantage of lightweight materials, such as aluminum alloys. Altec&#39;s aluminum utility and service bodies are 45% lighter than steel, and about 15% lighter than fiberglass. As a result, the lower vehicle weight further contributes to fuel savings and reduces tire and suspension wear and brake maintenance.</p> <p>Furthermore, Altec&rsquo;s manufacturing plant in Dixon, Calif., employs a vacuum infusion fiberglass process that uses 30% less resin and reduces styrene emission by 60%. The plant also applies powder-coat paint that emits no volatile organic compounds, produces minimal waste, and is durable and non-toxic.</p> <p>The Work Truck Show, one of the top 100 trade shows in the U.S., brings together more than 11,000 truck fleet managers, dealers, and equipment distributors every year in Indianapolis. It provides opportunities to network with other work-truck industry professionals on an exhibit floor covering more than 500,000 ft.<sup>2</sup>, and features a comprehensive educational conference. The 2017 Work Truck Show will be held at the Indiana Convention Center, Indianapolis, from March 15 to 17.</p> <p><em>For more information on Altec&rsquo;s JEMS hybrid technology and other Green Fleet Solutions, visit <a href="http://www.altec.com/products/green-fleet" target="_blank">www.altec.com/products/green-fleet</a>. For information on the Work Truck Show, visit <a href="http://www.ntea.com/worktruckshow" target="_blank">www.ntea.com/worktruckshow</a>.</em></p> <p><em>Looking for parts? Go to <a href="http://sourceesb.com/" target="_blank">SourceESB</a>.</em></p> <table border="0" cellpadding="0" cellspacing="0" width="570"> <tbody> <tr> <td width="41"><img src="http://insidepenton.com/electronic_design/adobe-pdf-logo-tiny.png" /></td> <td style="padding-left: 0px;" width="459"><a href="/datasheet/hydraulic-system-runs-engine-shut-pdf-download">Download this article in .PDF format</a><br /> This file type includes high-resolution graphics and schematics when applicable.</td> </tr> </tbody> </table> </div> http://hydraulicspneumatics.com/hydraulic-pumps-motors/hydraulic-system-runs-engine-shut#comments Hydraulic Fluids Hydraulic Pumps & Motors Rail, Truck & Bus Thu, 09 Jun 2016 13:48:00 +0000 38651 at http://hydraulicspneumatics.com Troubleshooting Challenge: Leaking Cylinder Puzzles Expert http://hydraulicspneumatics.com/cylinders-actuators/troubleshooting-challenge-leaking-cylinder-puzzles-expert <div class="node-body article-body"><table border="0" cellpadding="0" cellspacing="0" width="570"> <tbody> <tr> <td width="41"><img src="http://insidepenton.com/electronic_design/adobe-pdf-logo-tiny.png" /></td> <td style="padding-left: 0px;" width="459"><a href="/datasheet/troubleshooting-challenge-leaking-cylinder-puzzles-expert-pdf-download">Download this article in .PDF format</a><br /> This file type includes high resolution graphics and schematics when applicable.</td> </tr> </tbody> </table> <p>Several years ago when I owned a large hydraulic repair shop, we received defective power steering cylinders off of a popular Clark forklift truck to be repaired. The Clark dealer would give us 8 to 12 cylinders at a time. Some leaked externally around the rod seal area, some had large dents in the outer tube, and some were scarred internally. This required replacing the inner tube, piston, or both.</p> <div class="related-content"> <div class="related-label">Related</div> <p><a href="http://hydraulicspneumatics.com/hose-tubing/troubleshooting-challenge-hoses-pull-away-fittings">Troubleshooting Challenge: Hoses Pull Away from Fittings</a></p> <p><a href="http://hydraulicspneumatics.com/cylinders-actuators/troubleshooting-challenge-hpu-too-noisy">Troubleshooting Challenge: HPU Is Too Noisy</a></p> <p><a href="http://hydraulicspneumatics.com/hydraulic-pumps-motors/troubleshooting-challenge-cargo-ship-pressure-buildup-problem">Troubleshooting Challenge: Cargo Ship Pressure Buildup Problem</a></p> </div> <p>We mounted the cylinders in a lathe and cut through the weld to remove the blind end cap so we could remove the rod and piston assembly. After repairing or replacing parts, we reassembled, welded, and tested the assemblies, usually in batches of 8 to 12 units. I always insisted that nothing was allowed to leave our shop without testing, documentation, and stamping our job number on the repaired item.</p> <p><img alt="Forklift" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/06/Thinkstock-163882366.gif" style="width: 595px; height: 397px;" title="Image courtesy of Thinkstock" /></p> <p>We subsequently received some few complaints and warranty returns for leaking rod seals. However, when we tested the cylinders to see where they leaked, we could not get them to leak at any pressure. We would give the customer a rebuilt exchange at no charge and put the questionable cylinders in with the next batch to be repaired.</p> <p>The dealer called one day and insisted we go to one of his customers who purchased one of our &ldquo;leaking&rdquo; cylinders and installed it on his truck. When I arrived, the customer showed me a puddle of oil on the floor and wanted us to fix the problem. I cleaned up the oil mess and wiped the cylinder down, and asked their fork truck operator to drive around doing his job of moving stock for about a &frac12; hour and come back to where I was waiting. I then inspected the truck and could not find any oil leaking anywhere&mdash;but there sure was a puddle on the floor when I arrived.</p> <p>The cylinder seemed to leak overnight, but not when the lift truck was being used. What do you think was the source of the mystery leak?</p> <h3>Find the Solution</h3> <p>Think you know the answer to this month&rsquo;s problem? Submit your solution by e-mailing <a href="mailto:timmer@cfc-solar.com">Mindy Timmer</a>. All correct solutions submitted by July 5, 2016 will be entered into a random drawing for a $50 gift card. The winner will be notified, and his or her name will be printed in a future issue. Only one gift card will be awarded to any participant within a calendar year.</p> <p>Congratulations to Keith Hills, of Fisher-Hills Machinery, Sweetwater, Tex., who won our May puzzler by having his name picked from those who correctly answered that problem. A $50 gift card is in the mail to him.</p> <h3><a href="http://hydraulicspneumatics.com/hose-tubing/troubleshooting-challenge-hoses-pull-away-fittings" target="_blank">Solution to Last Month&rsquo;s Challenge: Hoses Pull Away From Fittings</a></h3> <p>When a hydraulic hose pulls out of its fittings, there normally are only a few causes. If the hose is installed in a straight line without any slack, pressure cycles that cause the hose to contract reduce its effective length, thereby creating a tensile force that tends to pull the hose away from the end fittings. The other primary cause would be hose fabrication error. In this case, the technicians were trained in hose fabrication and installation, so neither of these causes seemed apparent at first.</p> <p>However, we found that no one knew about measuring the crimp diameter of the fitting to verify the quality of the hose assembly. We found that the crimping dies were worn by more than 0.020 in. As a result, the connections were under crimped, causing the failures.</p> <p><em>Looking for parts? Go to&nbsp;<a href="http://www.SourceESB.com" target="_blank">SourceESB</a>.</em></p> <table border="0" cellpadding="0" cellspacing="0" width="570"> <tbody> <tr> <td width="41"><img src="http://insidepenton.com/electronic_design/adobe-pdf-logo-tiny.png" /></td> <td style="padding-left: 0px;" width="459"><a href="/datasheet/troubleshooting-challenge-leaking-cylinder-puzzles-expert-pdf-download">Download this article in .PDF format</a><br /> This file type includes high resolution graphics and schematics when applicable.</td> </tr> </tbody> </table> </div> http://hydraulicspneumatics.com/cylinders-actuators/troubleshooting-challenge-leaking-cylinder-puzzles-expert#comments Cylinders & Actuators Wed, 08 Jun 2016 14:09:00 +0000 38611 at http://hydraulicspneumatics.com Troubleshooting Challenge: Leaking Cylinder Puzzles Expert (.PDF Download) http://hydraulicspneumatics.com/datasheet/troubleshooting-challenge-leaking-cylinder-puzzles-expert-pdf-download <div class="node-body datasheet-body"><p>Several years ago when I owned a large hydraulic repair shop, we received defective power steering cylinders off of a popular Clark forklift truck to be repaired. The Clark dealer would give us...</p> <p><strong>Register or sign in below to download the full article in .PDF format, including high resolution graphics and schematics when applicable.</strong></p> <div class="gatedLogin well"> <div class="contentPadding clearfix"> <h2>Register for Complete Access (Valid Email Required)</h2> <p><p><img height="auto" src="http://hydraulicspneumatics.com/site-files/hydraulicspneumatics.com/files/uploads/2015/08/full-wallchart.JPG" width="100%" />By registering on Hydraulics &amp; Pneumatics now, you&#39;ll not only gain access to , you&#39;ll also receive a complimentary copy of <em>Hydraulics & Pneumatics Wall Chart</em>.</p> </p> <div class="gatedLoginButtons gated-register-button"> <div class="button-region"> <a href="/penton_ur/nojs/user/register?source=gated&nid=38631&regmode=1" class="ctools-use-modal btn btn-branded btn-wide ctools-modal-register" title="Register at this site.">Register</a> </div> <div class="loginLinkText"> Already registered? <a href="/penton_ur/nojs/login" class="ctools-use-modal ctools-modal-log_in" title="">Log In</a> here. </div> </div> </div> </div> </div> Gold Wed, 08 Jun 2016 14:02:00 +0000 38631 at http://hydraulicspneumatics.com Hydraulic-Electric Analogies: Internal Gear Pumps http://hydraulicspneumatics.com/hydraulic-pumps-motors/hydraulic-electric-analogies-internal-gear-pumps <div class="field-deck"> Although usually associated with low-speed, high-torque motors, the gerotor element also works effectively as a pump. </div> <div class="node-body article-body"><table border="0" cellpadding="0" cellspacing="0" width="570"> <tbody> <tr> <td width="41"><img src="http://insidepenton.com/electronic_design/adobe-pdf-logo-tiny.png" /></td> <td style="padding-left: 0px;" width="459"><a href="/datasheet/hydraulic-electric-analogies-internal-gear-pumps-pdf-download">Download this article in .PDF format</a><br /> This file type includes high-resolution graphics and schematics when applicable.</td> </tr> </tbody> </table> <p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/07/MotionFig-9.png" style="width: 300px; height: 321px; float: left;" title="9. The basic gerotor set consists of inner (purple) and outer (dark blue) elements, both of which spin about non-concentric centers. The inner is driven externally through the shaft." />Several different types of internal gear pump designs exist, but only the gerotor (contraction of the words, &ldquo;generated rotor&rdquo;) has achieved wide commercial adoption in hydraulic fluid-power applications. Early attempts date to efforts by Galloway in 1787, with others adding to its development in the intervening centuries. W. H. Nichols was the first to develop gerotor mass-production techniques back in the 1920s. Eventually, a family of pumps and motors grew up around the basic gear set.</p> <p><em>Figure 9</em> shows a basic gerotor gear set in three dimensions. An outer gear has one more lobe than an inner gear&mdash;an essential feature to the function of the pump. A shaft connects the rotating group to an external prime mover via the inner gear element. Both the inner and outer elements rotate, but do so around non-concentric centers. The eccentricity, along with inner gear tips that self-seal against the outer gear contours, provides the pumping action.&nbsp;</p> <div class="related-content"> <div class="related-label">Related</div> <p><a href="http://hydraulicspneumatics.com/hydraulic-pumps-motors/hydraulic-electric-analogies-part-2-adding-variable-positive-displacement">Hydraulic-Electric Analogies: Part 2&mdash;Adding a Variable to Positive Displacement</a></p> <p><a href="http://hydraulicspneumatics.com/hydraulic-pumps-motors/hydraulic-electric-analogies-simple-and-efficient">Hydraulic-Electric Analogies: Simple and Efficient</a></p> <p><a href="http://hydraulicspneumatics.com/hydraulic-pumps-motors/hydraulic-electric-analogies-hydraulic-power-conversion-part-4">Hydraulic-Electric Analogies: Hydraulic Power Conversion, Part 4</a></p> <p><a href="http://hydraulicspneumatics.com/hydraulic-pumps-motors/hydraulic-electric-analogies-hydraulic-power-conversion-part-3">Hydraulic-Electric Analogies: Hydraulic Power Conversion, Part 3</a></p> <p><a href="http://hydraulicspneumatics.com/hydraulic-pumps-motors/hydraulic-electric-analogies-hydraulic-power-conversion-part-2">Hydraulic-Electric Analogies: Hydraulic Power Conversion, Part 2</a></p> </div> <p>As with all pumps, the inner rotating parts are nested in a close-fitting, stationary body <em>(Fig. 10)</em>. The yellow outlet port is hydraulically connected to the yellow internal kidney port, while the blue inlet port is connected to the internal blue kidney. The blue port delivers low-pressure fluid into the expanding gerotor set chambers, and the yellow port carries the positively expelled output flow.</p> <p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/07/MotionFig-10.png" style="width: 300px; height: 240px; float: right;" title="10. Similar to vane pumps, the gerotor pump body has a precisely machined receiving cavity and kidney ports to carry dc hydraulic flow to the outside world." />When the gerotor set is installed in the body <em>(Fig. 11)</em>, visualize that the rotating gear set is turning, say, CCW. The inter-gear chambers in communication with the blue kidney are thus expanding, causing a pressure reduction (partial vacuum) so that external atmospheric pressure pushes fluid into those expanding chambers. In contrast, the chambers in communication with the yellow kidney are decreasing, positively expelling fluid to emerge from the outlet port. This is a clear case of positive displacement at work.</p> <p><em>Figure 12</em> illustrates the relative positions of the inner and outer gears in a gerotor pump. Recall that the blue kidney port is the inlet and the yellow is the outlet. At whatever angle the gerotor is positioned, the design of the outer gear is such that the lobes on the inner are always in near contact with the inside contours of the outer gear.</p> <p>This near-contact forms a sliding seal and creates expanding and contracting trapped chambers. The chambers expand when in communication with the inlet kidney and contract while in contact with the outlet kidney. In this respect, it&rsquo;s very much like the vane pumps. The gerotor pump is necessarily fixed displacement.</p> <p><strong><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/07/MotionFig-11.png" style="width: 300px; height: 240px; float: left;" title="11. The blue side of the pump assembly forms the input, while the yellow side is the outlet, high-pressure side." />Variations on the Gerotor Machine</strong></p> <p>Like most pumps, the gerotor element is fully capable of functioning as a motor. With the exception of somewhat higher power density, gerotor motors hold no special advantage over spur gear motors.</p> <p>A variation from standard construction results in a very large effective displacement in a very small package. The idea uses an outer gear that does not rotate, but is locked to the body. The rotor rolls around inside the outer gear and is said to orbit because the centerline of inner element varies with rotation. To couple the varying internal center of rotation with an external shaft that has a fixed center of rotation, an internal shaft, referred to by some as a &ldquo;dog bone,&rdquo; must have a double universal joint.</p> <p>The motors also must be equipped with a rotating port plate to replace the fixed kidney ports. That&rsquo;s because the various gerotor chambers change from pumping to absorbing, depending on the inner element&rsquo;s orbit position. These motors are considered low-speed, high-torque (LSHT) designs. The orbiting inner rotor produces an internal equivalent gear reduction.</p> <p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/07/MotionFig-12.png" style="width: 595px; height: 419px;" title="12. Progressive coordinated rotations of the gerotor set shows how the inter-lobe volumes increase and decrease, and how the inner’s lobe makes new contact with the outer ring’s lobes." /></p> <p>More detail on this motor type is beyond the scope of this brief summary of electric-hydraulic analogies. Interested readers should refer to the many fine tests that explore the function and characteristics in greater detail.&nbsp;</p> <p><em>Looking for parts? Go to <a href="http://sourceesb.com/" target="_blank">SourceESB</a>.</em></p> <table border="0" cellpadding="0" cellspacing="0" width="570"> <tbody> <tr> <td width="41"><img src="http://insidepenton.com/electronic_design/adobe-pdf-logo-tiny.png" /></td> <td style="padding-left: 0px;" width="459"><a href="/datasheet/hydraulic-electric-analogies-internal-gear-pumps-pdf-download">Download this article in .PDF format</a><br /> This file type includes high-resolution graphics and schematics when applicable.</td> </tr> </tbody> </table> </div> http://hydraulicspneumatics.com/hydraulic-pumps-motors/hydraulic-electric-analogies-internal-gear-pumps#comments Hydraulic Pumps & Motors Wed, 08 Jun 2016 13:06:00 +0000 38601 at http://hydraulicspneumatics.com Gain Control of the Flow http://hydraulicspneumatics.com/hydraulic-valves/gain-control-flow <div class="field-deck"> Designers rely on flow-control valves to regulate actuator speed. But different situations call for different types of valves, so this guide explains what can be used where and why. </div> <div class="node-body article-body"><table border="0" cellpadding="0" cellspacing="0" width="570"> <tbody> <tr> <td width="41"><img src="http://insidepenton.com/electronic_design/adobe-pdf-logo-tiny.png" /></td> <td style="padding-left: 0px;" width="459"><a href="/datasheet/gain-control-flow-pdf-download">Download this article in .PDF format</a><br /> This file type includes high resolution graphics and schematics when applicable.</td> </tr> </tbody> </table> <p>Hydraulic circuits usually have a dedicated power source sized to meet the cycle time, making flow restrictors &shy;unnecessary. Flow controls always generate some heat in hydraulic circuits, so consider some other method of controlling actuator speed when possible. The circuit examples presented here explain the types of flow-control systems and how to apply them.</p> <div class="related-content"> <div class="related-label">Related</div> <p><a href="http://hydraulicspneumatics.com/hydraulic-filters/smart-components-enhance-hydroelectric-turbine-flow-control">Smart Components Enhance Hydroelectric-Turbine Flow Control</a></p> <p><a href="http://hydraulicspneumatics.com/cylinders-actuators/market-report-explores-hydraulic-cylinder-industry">Market Report Explores Hydraulic Cylinder Industry</a></p> <p><a href="http://hydraulicspneumatics.com/cylinders-actuators/troubleshooting-challenge-hpu-too-noisy">Troubleshooting Challenge: HPU Is Too Noisy</a></p> </div> <p><em>Figure 1</em> shows symbols for a simple fixed orifice (a rudimentary component that restricts flow) and a fixed orifice with pressure and temperature compensation. A fixed orifice can be a simple restriction in a line or a factory-preset control with pressure compensation and a bypass. Their low cost and tamper-proof operation are two main reasons for using fixed orifices.</p> <p><img alt="Fig. 1" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/06/Flow-Control-fig-1.png" style="width: 300px; height: 375px; margin: 5px; float: left;" title="1. Shown are standard symbols for flow-control valves: a fixed orifice, top, and a fixed orifice with pressure and temperature compensation. " /><em>Figure 2</em> shows the symbol for a simple needle valve (top), which is used when fluid flow must be controlled in both directions. The needle valve with a check valve added (bottom) provides pressure compensation in both directions of flow. Pressure compensation only occurs in one direction of flow, so these check valves, sometimes referred to as <em>bridge rectifiers</em>, force fluid through the needle valve in the same direction regardless of actuator movement.</p> <p>Not surprisingly, nomenclature sometimes confuses this issue in identifying flow-control hardware. Normally, the term <em>flow control</em> refers to an adjustable needle valve with an integral bypass <em>(Fig. 3)</em>. This type of flow control meters flow in one direction and allows free flow in the opposite direction. However, some companies identify the valve in Fig. 3 as a <em>throttle valve</em> because it does not provide pressure compensation. The needle valve represented in <em>Fig. 4</em> does provide pressure- and temperature-compensated flow in one direction.</p> <p>When a hydraulic actuator needs accurate speed control, use a pressure-compensated flow control. Otherwise, system pressure fluctuations or load changes will affect actuator velocity. Regardless of the cause of the pressure differences, flow across the orifice will change unless the flow control is pressure compensated. However, pressure-compensated valves cost several times that of the non-compensated variety, so use them only when very accurate speed control is needed.</p> <p><img alt="Fig. 2" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/06/Ag-Fig-2.jpg" style="width: 595px; height: 383px;" title="2. Standard symbols represent a variable orifice flow control, top, and a variable orifice with check valves for bidirectional pressure and temperature compensation." /></p> <h3>Types of Flow-Control Circuits</h3> <p>Three types of flow control circuits are most common: <em>meter-in</em>, <em>meter-out</em>, and <em>bleed-off</em> (sometimes called <em>bypass</em>). Each circuit has advantages for particular situations.</p> <p><em>Figure 5</em> shows a <strong>meter-in </strong>flow control with the pressures and flows indicated while the cylinder is extending. Notice that a bypass check valve forces fluid through an adjustable orifice just before it enters the cap end of the cylinder. With a meter-in circuit, fluid enters the actuator at a controlled rate. If the actuator has a resistive load, movement will be smooth and steady because hydraulic fluid can be considered incompressible in most cases.</p> <p><img alt="Fig. 3" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/06/Flow-control-fig-3.png" style="width: 300px; height: 300px; margin: 5px; float: left;" title="3. A needle valve generally contains a variable-orifice flow control and bypass circuit for metered flow in one direction and free flow in the opposite direction. Some companies refer to this as a throttle valve." />In pneumatic systems, however, cylinder movement may be jerky because of air&rsquo;s compressibility. As air flows into a cylinder, pressure increases until it generates the force needed to overcome static friction to start moving the load. Because the force needed to keep the load moving is less than the breakaway force (because dynamic friction is less than static), the air in the cylinder actually expands until static friction stops the piston. Pressure builds again to overcome static friction, and the process repeats. This lunging movement can continue to the end of the stroke. A meter-out circuit prevents this stick-slip motion (stiction).</p> <p>A meter-in flow control will not work if the actuator has an overrunning load (the load pulls on the piston rod). When the directional valve shifts, a strong tensile load on the cylinder rod makes it extend. Because fluid cannot enter the cylinder&rsquo;s cap end fast enough, a partial vacuum void forms in the line. The cylinder then free falls, regardless of the setting of the meter-in flow adjustment. The pump will continue to supply metered fluid to the cap end of the cylinder and will eventually fill the void. The cylinder can produce full force after the void has been filled.</p> <p><img alt="Fig. 4" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/06/Flow-control-fig-4.png" style="width: 300px; height: 375px; margin: 5px; float: left;" title="4. This needle valve differs from the throttle valve by providing pressure and temperature compensated flow control in one direction, and free flow in the other." /><strong>Meter-out flow controls</strong> restrict fluid leaving the cylinder to retard the cylinder&rsquo;s movement. This type of flow-control circuit works for any type of load&mdash;and it works best with air-operated devices.</p> <p><em>Figure 6</em> shows a meter-out circuit with the cylinder extending. Fluid in the cap end is at system pressure, and the relief valve dumps excess pump flow to tank. Pressure at the rod end of the cylinder will be at system pressure or higher according to the rod size and force required to move the load. The action of meter-out flow controls is smooth and steady for hydraulic and pneumatic circuits.</p> <p><em>Figure 7</em> represents a meter-out flow control regulating the load on a down-acting vertical cylinder. This over-running load moves steadily because the circuit restricts flow leaving the cylinder. The meter-out circuit keeps the load from running away but, depending on the load and the rod size, excessive pressure could exist in the cylinder&rsquo;s rod end. Notice in this case that the rod-end pressure is 3,000 psi when extending. This is because the rod is oversized (2:1) and the load is heavy. At a relief valve setting of 3,000 psi, this rod-end pressure could be as high as 7,000 psi.</p> <p><img alt="Fig. 5" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/06/Flow-control-fig-5.png" style="width: 595px; height: 799px; margin: 0px;" title="5. Meter-in circuits provide smooth motion for hydraulic systems with a resistive load, but can produce jerky, stick-slip operation with pneumatics. " /></p> <p>A <strong>bleed-off flow-control</strong> circuit extending a cylinder is represented in <em>Fig. 8</em>. Bleed-off flow controls often are referred to as <em>bypass</em> flow controls. This type of flow control circuit bleeds off excess fluid to tank. A bleed-off flow control works best in hydraulic circuits using fixed-displacement pumps. However, a bleed-off circuit only works with multiple actuators if they operate one at a time.</p> <p><img alt="Fig. 6" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/06/Flow-control-fig-6.png" style="width: 595px; height: 707px; margin: 0px;" title="6. Meter-out circuits provide smooth motion for both resistive and over-running loads in hydraulics and in pneumatic systems. Their versatility has led to many instructors to advise, “When in doubt, meter out.”" /></p> <p>When oil passes to tank through a pressure-compensated flow control, cylinder movement will slow while system pressure rises only high enough to move the load. Although this arrangement wastes energy, the amount is minimal. For example, the cylinder in Fig. 8 extends at 3 gpm while 7 gpm passes to tank through the pressure-compensated needle valve. Because the resistance of the cylinder and load is only 100 psi, the wasted energy is low. In most cases, use a bleed-off circuit where only a small amount of fluid goes to tank in fine-tuning actuator speed.</p> <p>The 3 gpm flowing to the cylinder generates no heat because it is doing useful work. The 7 gpm going to tank at a 100-psi pressure drop is the only wasted energy&mdash;but only 1,038 btu in this case. If the cylinder engaged a load requiring 300 psi, then the whole system would climb to 300 psi. Energy loss would increase but still would be much less than in a meter-in or meter-out circuit.</p> <p><img alt="Fig. 7" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/06/Flow-control-fig-7.png" style="width: 595px; height: 772px; margin: 0px;" title="7. Meter-out circuits work well with over-running loads by limiting the speed of extension, whether the load puts the piston rod in compression or tension. " /></p> <p>Even with a pressure-compensated flow control valve, cylinder speed in a bleed-off circuit will decrease slightly as pressure increases. This is because pump flow decreases slightly when pressure increases. The flow control still passes 7 gpm, and when the cylinder bottoms out, pressure increases until the relief valve opens. At that time all input energy generates heat. Note, however, that this only occurs when the cylinder must maintain force while stalled.</p> <p><img alt="Fig. 8" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/06/Flow-control-fig-8.png" style="width: 595px; height: 749px; margin: 0px;" title="8. An energy-efficient alternative to meter-in and meter-out circuits, a bleed-off flow control works best in hydraulic circuits using fixed-displacement pumps, and it only works with multiple actuators if they operate one at a time." /></p> <p>As with meter-in circuits, bleed-off circuits do not work with an over-running load. As <em>Fig. 9</em> shows, an over-running load can create a partial vacuum (negative pressure) in the pump line. When using a bleed-off circuit with an over-running load, use a counterbalance valve to create resistance.</p> <p>As with any resistive load, fluid entering the cylinder determines extension and retraction speed. A bleed-off circuit requires a pressure-compensated flow control to keep the cylinder from slowing as pressure increases. Otherwise, cylinder speed will slow down as load increases and speed up when load decreases.</p> <p><img alt="Fig. 9" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/06/Flow-control-fig-9.png" style="width: 595px; height: 670px; margin: 0px;" title="9. This schematic depicts an over-running load. If a tensile load pulls on the cylinder’s piston rod faster than the pump can fill the expanding cap-end volume, speed will be uncontrolled and a partial vacuum will be created in the pump line. " /></p> <p><em>This information was excerpted from &ldquo;Fluid Power Circuits Explained,&rdquo; an e-book written by Bud Trinkel and edited by Hydraulics &amp; Pneumatics. Learn more about flow control valves and circuits and many other fluid power fundamentals <a href="http://hydraulicspneumatics.com/learning-resources/ebooks" target="_blank">here</a></em>.</p> <p><em>Looking for parts? Go to&nbsp;<a href="http://www.SourceESB.com" target="_blank">SourceESB</a>.</em></p> <table border="0" cellpadding="0" cellspacing="0" width="570"> <tbody> <tr> <td width="41"><img src="http://insidepenton.com/electronic_design/adobe-pdf-logo-tiny.png" /></td> <td style="padding-left: 0px;" width="459"><a href="/datasheet/gain-control-flow-pdf-download">Download this article in .PDF format</a><br /> This file type includes high resolution graphics and schematics when applicable.</td> </tr> </tbody> </table> </div> http://hydraulicspneumatics.com/hydraulic-valves/gain-control-flow#comments Hydraulic Valves Tue, 07 Jun 2016 15:30:00 +0000 38561 at http://hydraulicspneumatics.com Gain Control of the Flow (.PDF Download) http://hydraulicspneumatics.com/datasheet/gain-control-flow-pdf-download <div class="node-body datasheet-body"><p>Hydraulic circuits usually have a dedicated power source sized to meet the cycle time, making flow restrictors &shy;unnecessary. Flow controls always generate some heat in hydraulic circuits, so consider...</p> <p><strong>Register or sign in below to download the full article in .PDF format, including high resolution graphics and schematics when applicable.</strong></p> </div> Tue, 07 Jun 2016 14:35:00 +0000 38581 at http://hydraulicspneumatics.com Stick-Slip Happens, But How? http://hydraulicspneumatics.com/cylinders-actuators/stick-slip-happens-how <div class="field-byline"> Yasunori Wakasawa, Yuhi Ito, and Hideki Yanada </div> <div class="field-deck"> Breakaway friction makes smooth acceleration from rest a challenge with pneumatic cylinders. Developing a mathematical model offers a glimpse into the forces at work and reveals some surprising observations. </div> <div class="node-body article-body"><table border="0" cellpadding="0" cellspacing="0" width="570"> <tbody> <tr> <td width="41"><img src="http://insidepenton.com/electronic_design/adobe-pdf-logo-tiny.png" /></td> <td style="padding-left: 0px;" width="459"><a href="/datasheet/stick-slip-happens-how-pdf-download">Download this article in .PDF format</a><br /> This file type includes high-resolution graphics and schematics when applicable.</td> </tr> </tbody> </table> <p>Pneumatic cylinders are widely used throughout industry because of their relatively large output-power-to-size ratio, easy operation, safety, etc. However, precise control of these cylinders can be difficult due to their highly nonlinear friction characteristics and the compressibility of air. Consequently, their applications are limited to point-to-point control operations.</p> <div class="related-content"> <div class="related-label">Related</div> <p><a href="http://hydraulicspneumatics.com/cylinders-actuators/pneumatic-cylinder-design-factors">Pneumatic Cylinder Design Factors</a></p> <p><a href="http://hydraulicspneumatics.com/pneumatic-valves/10-safety-products-every-pneumatic-tool-kit">10 Safety Products for Every Pneumatic Tool Kit</a></p> <p><a href="http://hydraulicspneumatics.com/controls-instrumentation/taking-guesswork-out-pneumatic-control">Taking the Guesswork Out of Pneumatic Control</a></p> </div> <p>To achieve accurate positioning of a pneumatic cylinder, the nonlinear friction characteristics need to be made clear and expressed by a mathematical model. In addition, by developing a mathematical model for the friction characteristics, the dynamic behaviors of a pneumatic cylinder system can be accurately predicted by simulation at its design stage. This helps reduce design time, enhance the quality of controller designs, and improve component selection.</p> <p>Some characteristics of nonlinear friction on pneumatic-cylinder motion are well documented, as are the experimental and numerical studies of the friction between the seals and the cylinder bore, especially stick-slip motion. Many of these studies focus on the chaotic oscillations that occur during low-speed actuation. Other studies investigated the dynamic friction behavior of pneumatic cylinders&mdash;however, experimental conditions were limited, and vibration characteristics were not examined. Therefore, the nonlinear friction behavior of pneumatic cylinders still has yet to be fully examined and modeled.</p> <p>The study presented here investigates the dynamic friction and vibration characteristics of a pneumatic cylinder, as well as the relation between the friction and vibration.</p> <p><strong>Experimental Apparatus and Method</strong></p> <p><em>Figure 1 </em>shows a simplified representation of the experimental apparatus. A standard pneumatic cylinder was used for the test.&nbsp; It had a bore of 32 mm, rod diameter of 12 mm, and stroke of 300 mm. The test cylinder was fixed perpendicular to a horizontal table. A potentiometer and two pressure sensors were used to measure the cylinder&rsquo;s piston position and pressures in its rod- and cap-end chambers. Three accelerometers attached to the cylinder measured the vibration of the piston in the x (radial), y (radial, perpendicular to x), and z (axial) directions.</p> <p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/07/0616_HP_Automate_F1a.gif" style="width: 595px; height: 589px;" title="1. The drawing (a) shows a simplified test rig for measuring key parameters that influence friction in pneumatic cylinders. The photo below shows the actual test rig (b)." /></p> <p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/07/0616_HP_Automate_F1b.jpg" style="width: 595px; height: 560px;" /></p> <p>In the experiments, the cylinder operated only when extending the piston rod. The flow rate of air supplied to the cylinder was controlled by the proportional flow-control valves. The piston speed was varied in a stepwise or sinusoidal profile to investigate the steady-state and dynamic friction characteristics and their effect on the vibration characteristics. Piston speed was calculated by differentiating the position over time.</p> <p>Friction force is obtained from the equation of motion of the pneumatic piston:</p> <p align="center"><em>F</em> = <em>p</em><sub>1 </sub><em>A</em><sub>1</sub> &ndash; <em>p</em><sub>2 </sub><em>A</em><sub>2</sub> &ndash; m<sub>g</sub> &ndash; m<sub>a</sub></p> <p>where <em>F</em> is the friction force; <em>m</em> is the mass of the pneumatic piston; <em>p</em><sub>1</sub> and <em>p</em><sub>2</sub> are the pressures in rod- and cap-end chambers of the cylinder; <em>A</em><sub>1</sub> and <em>A</em><sub>2</sub>&nbsp; are the areas the rod- and cap-end sides of the piston; <em>a</em> is the acceleration of the piston; and<em> g</em> is acceleration due to gravity.</p> <p><strong>Test Results</strong></p> <p><em>Figures 2</em> and <em>3</em> show a typical example of the measured position, velocity, friction force, and acceleration in the z (axial) direction of the cylinder when a stepwise signal was supplied to the proportional control valves. Fig. 2 illustrates how the linear variation of position and velocity varied in nearly incremental steps.</p> <p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/07/0616_HP_Automate_F2.gif" style="width: 595px; height: 353px;" title="2. Plots show results of piston position and velocity over time typical of texts. Position closely followed a linear path, whereas velocity varied almost stepwise." /></p> <p><em>Figure 3 </em>shows the variation of the friction force with time and reveals three observations. First, the maximum friction force (<em>F<sub>max</sub></em>) appears immediately as the cylinder&rsquo;s piston begins to move. Second, the minimum friction force (<em>F<sub>min</sub></em>) occurs just after the maximum friction force. Third, a relatively steady friction force eventually occurs. Friction characteristics similar to Fig. 3 were observed at different stepwise velocities.</p> <p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/07/0616_HP_Automate_F3.gif" style="width: 595px; height: 356px;" title="3. Changes in friction force with time reveal that maximum friction occurs immediately after the onset of cylinder operation, and minimum friction occurs just after maximum friction." /></p> <p><em>Figure 4</em> illustrates the variation of the acceleration in z axis with time. The components of acceleration in x and y radial are not shown because they were negligible relative to the z component. The beginning of the piston&rsquo;s movement in Fig. 4 shows that the maximum acceleration <em>a<sub>z </sub><sub>max</sub></em>, occurs while the friction force rapidly decreases from maximum to minimum. Vibration characteristics similar to this were observed for other step changes in velocity.</p> <p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/07/0616_HP_Automate_F4.gif" style="width: 595px; height: 354px;" title="4. Axial acceleration peaks at the same time that friction rapidly decreases from maximum to minimum." /></p> <p>Static friction force occurs on the cylinder&rsquo;s contact surfaces until just before the piston starts to move. Increasing air pressure in the cylinder, of course, increases the force acting on the piston. When the force exceeds the maximum static friction force, the piston begins to move. At that instant, the friction force suddenly decreases due to the Stribeck effect&mdash;the negative resistance characteristic of friction. Therefore, the piston accelerates rapidly.</p> <p><em><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/07/0616_HP_Automate_F5.gif" style="width: 350px; height: 258px; float: left;" title="5. Dynamic friction is plotted with steady-state friction. Dynamic friction almost traces steady-state curve until encountering higher values of stepwise velocities." />Figure 5</em> shows the dynamic friction characteristic shown on the friction force/velocity plane and is compared to steady-state friction. The steady-state friction curve was obtained by plotting the steady-state values of friction force at different stepwise velocities. The dynamic friction force almost traces the steady-state friction characteristic and reaches a steady value. However, when the stepwise velocity is large, the dynamic friction force exceeds steady-state friction force in the low-speed region.</p> <p><strong>The Case for Half-Period Sinusoidal Velocity Variation </strong></p> <p><em>Figure 6</em> shows a typical example of the measured velocity and friction force when a half-period sinusoidal signal was supplied to the proportional control valves. Velocity varied almost sinusoidally except for the overshoot observed at the beginning of the motion. The variation of friction force with time, as seen in Fig. 6, indicates that maximum friction force appears immediately after the beginning of cylinder operation and minimum friction force is observed just after the maximum friction force.</p> <p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/07/0616_HP_Automate_F6.gif" style="width: 595px; height: 353px;" title="6. Measured velocity and friction force are plotted against time when proportional valves were supplied with half-period sinusoidal control signals. Except for the overshoot exhibited at the beginning of motion, the velocity varied almost sinusoidally. Once again, friction exhibited maximum and minimum values consistent with those in Fig. 3." /></p> <p>Dynamic-friction-force behavior at 1.0 Hz of the half-period sinusoidal velocity variation is given in <em>Figure 7</em>. The dynamic friction force, which is larger than the steady-state friction force during the acceleration period, traces the steady-state friction characteristic <img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/07/0616_HP_Automate_F7.gif" style="width: 350px; height: 278px; float: right;" title="7. Dynamic friction force behavior is shown for half-period sinusoidal velocity at a frequency of 1.0 Hz. The size of hysteresis loop increased with increases in frequency." />during the deceleration period, except for the negative resistance regime. We found that increasing the frequency of the velocity variation increased the size of the hysteresis. These behaviors agree with those reported by Tran, Wakasawa, and Yanada in &ldquo;Behaviors of Pneumatic Actuators,&rdquo; presented at ICMDT 2011.</p> <p>Stick-slip motion occurred at the mean velocity of 0.010 m/sec <em>(Fig. 8)</em>. <em>Figures 9a</em> and <em>9b</em> show how repeated velocity variations from zero to about 0.1 m/s caused the friction force, likewise, to oscillate.</p> <p>Figure 9a reveals the friction force behavior for the values of Fig. 8. Maximum friction force appears immediately after the beginning of cylinder operation. Figure 9b illustrates the hysteresis loop during the second cycle. As can be seen, the hysteresis loop is significantly smaller than that shown in Fig. 9a, even though the friction force is nearly constant.</p> <p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/07/0616_HP_Automate_F8.gif" style="width: 595px; height: 350px;" title="8. Stick-slip motion occurred at a mean velocity of 0.010 m/sec. Furthermore, repeated velocity variations from about 0 to 0.1 m/sec caused friction force to oscillate, also shown in the illustration." /></p> <p>We also examined the effect of dwell time on dynamic friction characteristics. <em>Figure 10 </em>shows the effect of the dwell time (<em>t<sub>d</sub></em>) on the breakaway force (<em>F<sub>b</sub></em>). As can be seen, the breakaway force increases with dwell time, but tends to approach a constant value as dwell time exceeds 120 sec.</p> <p><a href="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/07/0616_HP_Automate_F9-big.gif" target="_blank"><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/07/0616_HP_Automate_F9-big.gif" style="width: 595px; height: 248px;" title="9. Shown here is friction-force behavior based on Fig. 8. Maximum friction force occurs immediately after the onset of cylinder operation (a). The size of the hysteresis loop during the second cycle reduced substantially in (b), whereas friction force remained fairly constant. (Click image to enlarge)" /></a></p> <p><strong>Conclusions</strong></p> <p>The friction and vibration characteristics of a pneumatic cylinder in practical operations were examined under stepwise and half-period sinusoidal velocity variations. Tests indicated that a relatively large acceleration is caused at the start of cylinder motion, resulting mainly from a steep decrease in friction force immediately at the onset of motion.</p> <p><img alt="" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/07/0616_HP_Automate_F10.gif" style="width: 595px; height: 444px;" title="10. Tests showed that as dwell time increases, so does breakaway force, which increases almost linearly to about 60 sec. However, breakaway force levels off to nearly constant when dwell time exceeds 120 sec." /></p> <p>Hysteresis is frequency-dependent during acceleration and deceleration periods. Furthermore, a constant friction characteristic in stick-slip motion has been indicated. Modeling of dynamic friction behaviors will be the subject for a future study.</p> <p><em>Yasunori Wakasawa and Yuhi Ito are associated with the Toyota National College of Technology and Hideki Yanada is with Toyohashi University of Technology, both in Japan. This article is based on a paper presented at the Third International Conference on Design Engineering and Science, Pilsen, Czech Republic.</em></p> <p><em>Looking for parts? Go to <a href="http://sourceesb.com/" target="_blank">SourceESB</a>.</em></p> <table border="0" cellpadding="0" cellspacing="0" width="570"> <tbody> <tr> <td width="41"><img src="http://insidepenton.com/electronic_design/adobe-pdf-logo-tiny.png" /></td> <td style="padding-left: 0px;" width="459"><a href="/datasheet/stick-slip-happens-how-pdf-download">Download this article in .PDF format</a><br /> This file type includes high-resolution graphics and schematics when applicable.</td> </tr> </tbody> </table> </div> http://hydraulicspneumatics.com/cylinders-actuators/stick-slip-happens-how#comments Cylinders & Actuators Tue, 07 Jun 2016 14:04:00 +0000 38571 at http://hydraulicspneumatics.com One Thing You Must Check The Next Time You Change A Hydraulic Hose http://hydraulicspneumatics.com/blog/one-thing-you-must-check-next-time-you-change-hydraulic-hose <div class="node-body blog-body"><p>The hydraulic hose fabrication process - or more specifically - the hose cutting process introduces contamination. This comprises metal particles from the hose&#39;s wire reinforcement and the cutting blade itself, and polymer dust from the hydraulic hose&#39;s out cover and inner tube.<br /> <br /> The amount of contamination which enters the hose during cutting can be reduced by employing techniques such as using a wet cutting blade instead of a dry one, blowing clean air through the hose as it is being cut and/or using a vacuum extraction device. The latter two aren&#39;t very practical when cutting long lengths of hose from a roll or in a mobile hydraulic hose-van situation.<br /> <br /> Therefore the main focus must be on effectively removing this cutting residue - and any other contamination that might be present in a hydraulic hose - prior to its installation. The most efficient and therefore most popular way of doing this is by blowing a foam cleaning projectile through the hose.<br /> <br /> The manufacturers of these cleaning systems claim that hose cleanliness levels as good as ISO 4406 15/13/10 are achievable. But like most everything else, the results achieved depend on a number of variables, which include using a projectile of the correct diameter for the hose being cleaned, whether the projectile is used dry or wetted with solvent, and the number of shots fired. Generally, the higher the number of shots, the cleaner the hose assembly. Oh, and if it is a new hose assembly that&#39;s being cleaned, the projectile cleaning should be done BEFORE the ends are crimped on.<br /> <br /> Almost all hydraulic hose fabricators these days have and use hose cleaning projectiles. But how meticulous they are when doing it is another matter entirely. This means if you want to ensure you take delivery of hydraulic hose assemblies to a certain standard of cleanliness, it&#39;s something you must specify and insist upon - as this little story from one of our members illustrates:<br /> <br /> <em>&quot;I was changing some hydraulic hoses on a Komatsu 300 HD for a customer and he noticed me washing out a hose before I put it on, so he asked: &#39;They clean them when they make them don&#39;t they?&#39; I said yup, but I like to check. I took the caps off a new hose and washed it with solvent and emptied the contents into some paper towel as he watched. His response was wholly sh-t!&quot;</em><br /> <br /> And it&#39;s not just the standard of the cleaning which must be insisted upon. A few years back I was at a customer&#39;s premises when their hydraulic hose supplier arrived to deliver a big bunch of hose assemblies. When the pallet came off the truck it was obvious to anyone with eyes that none of the hoses were capped to prevent contaminant ingression. And the customer accepted them. Nuts!<br /> <br /> As soon as I saw what was going on, I advised this customer to require all hoses be delivered with caps installed and not to accept them otherwise. This sort of penny foolishness should not be tolerated from any hydraulic hose fabricator.<br /> <br /> <strong>Bottom line</strong>: failing to properly clean a hydraulic hose after fabrication--and capping its ends, can be a costly mistake. And to discover six other costly mistakes you want to be sure to avoid with your hydraulic equipment, <a href="http://www.hydraulicsupermarket.com/track?p=handp&amp;w=smr"><strong>get &quot;Six Costly Mistakes Most Hydraulics Users Make... And How You Can Avoid Them!&quot; available for FREE download here</strong></a>.</p> </div> http://hydraulicspneumatics.com/blog/one-thing-you-must-check-next-time-you-change-hydraulic-hose#comments Hydraulics At Work Tue, 07 Jun 2016 00:41:00 +0000 38551 at http://hydraulicspneumatics.com Corn Processing Hits New Speeds With Hydraulics http://hydraulicspneumatics.com/hydraulic-pumps-motors/corn-processing-hits-new-speeds-hydraulics <div class="field-deck"> By replacing a de-kernelling machine’s mechanical drives with hydraulic motors, designers dramatically increased production and slashed maintenance. </div> <div class="node-body article-body"><table border="0" cellpadding="0" cellspacing="0" width="570"> <tbody> <tr> <td width="41"><img src="http://insidepenton.com/electronic_design/adobe-pdf-logo-tiny.png" /></td> <td style="padding-left: 0px;" width="459"><a href="/datasheet/corn-processing-hits-new-speeds-hydraulics-pdf-download">Download this article in .PDF format</a><br /> This file type includes high resolution graphics and schematics when applicable.</td> </tr> </tbody> </table> <p>Ron Anderson and Tom Kessler, co-founders of A&amp;K Development Co., Eugene, Oreg., had plenty of ambition when they formed their company. Both had experience in the food processing industry and many ideas about incorporating hydraulics into a new generation of corn processing machines. With the assistance of a local fluid power distributor, their ideas became reality.</p> <div class="related-content"> <div class="related-label">Related</div> <p><a href="http://hydraulicspneumatics.com/hydraulic-fluids/dehydrator-saves-day-contractor">Dehydrator Saves the Day for Contractor</a></p> <p><a href=" http://hydraulicspneumatics.com/forestry-lumber/tree-processor-comes-full-circle-hydraulic-swivels">Tree Processor Comes Full Circle with Hydraulic Swivels</a></p> <p><a href=" http://hydraulicspneumatics.com/hydraulic-pumps-motors/oxbo-technology-grape-harvesters">Oxbo Technology for Grape Harvesters</a></p> </div> <h3>Sweet Corn Processing</h3> <p>After it has been harvested, sweet corn is brought to a food processing plant and dumped down a chute to corn huskers. As the ears move down the face of the husker, dozens of rubberized rollers rip the husk away. All of the husk is gone by the time the ears reach the bottom of the husker, where they are conveyed to the next step in production.</p> <p><img alt="Fig. 1" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/06/Ag-Fig-1-.jpg" style="width: 595px; height: 390px;" title="Two conveyors transporting processed sweet corn dominate this view of a food plant. Multiple processing stations on each conveyor are visible near top of image. Each station can remove kernels from more than 100 ears of corn per minute." /></p> <p>From a series of conveyors, the ears reach an orienting station. Here, the ears are arranged parallel. However, some ears have their stem-end facing left and &nbsp;their silk-end facing left. To move the ears so they all point in the same direction, the ears advance to a series of angled thin plates that oscillate vertically. Ears are lifted by thin platforms and move to the next successively higher one. The movement looks as though the ears are ascending a set of stairs. When ears reach the top of the orienter, they drop to another conveyor.</p> <p>Before ears reach the conveyor, though, a strategically placed friction plate catches the wider (stem) end of the ear as it falls, tipping the pointed end downward. The forward movement of the conveyor pulls the ear from the friction plate, ensuring that each ear proceeds silk-end first.</p> <p><img alt="Fig. 2" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/06/Ag-Fig-2.jpg" style="width: 595px; height: 383px;" title="Orienter, at left, moves ears up a walking conveyor and releases them to a friction plate that ensures they all face the same direction. They are then conveyed to a de-kernelling station (at right, hidden behind hoses) that removes kernels from the cobs." /></p> <p>A&amp;K chose four geroler-type hydraulic motors to move, isolate, and orient the corn. Geroler motors were chosen because of their low-speed, high-torque operation and their ability to be kept in synchronization&mdash;a key part of the design of the orienter.</p> <p>The hydraulically powered orienter has a higher efficiency than competitive models, with a resulting tip-first orientation of greater than 90%. All the motors are power by tandem-mounted gear pumps. These pumps were chosen for their long life, high efficiency, and quiet operation.</p> <h3>Solving an Age-Old Problem</h3> <p>The biggest challenge for this application, however, is the de-kerneller&mdash;the device that removes the kernels from the cob with near-surgical precision. And although no major design changes had been made to the machine in more than 40 years, both Anderson and Kessler were determined to overcome one shortcoming inherent to the design.</p> <p><img alt="Fig. 3" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/06/Ag-Fig-3.jpg" style="width: 595px; height: 403px;" title="Each ear enters the de-kernelling station from right, and two pairs of hourglass-shaped rollers drive it to the left through the cutter head, which has been removed for clarity. As the ear emerges through the cutter, a third set of rollers pulls the spent cob to the left and pushes it out of the station." /></p> <p>Key to the de-kerneller is a series of six hourglass-shaped rolls arranged in three parallel pairs. The first two pairs of rolls feed individual ears to a dilating aperture cutting head, which opens and closes like a camera iris. As the ear passes through, blades on the cutting head cut the kernels from the cob. Then the final two hourglass rolls pull the spent cob from the machine.</p> <p>In the original design, a large gearbox and six universal joints transmitted power to each of the six rolls and the cutter. When a cob became lodged in the cutter, sensors instructed the machine to instantly reverse. These reversals occurred several times an hour, and the stress and wear took their toll on the brass gears and the universal joints. Consequently, they had to be replaced at least once per season.</p> <p>Anderson and Kessler were well aware of the success hydraulics had already demonstrated in other rugged areas of agriculture and food processing, so they decided to replace the bulky and maintenance-prone gearboxes with hydraulic motors. They chose the same series of hydraulic motors as used on the orienter, using a single motor to drive each of the six shafts (a seventh motor drives the cutter itself). The seven motors are connected in series, which keeps their speeds closely matched. Closely synchronized speed prevents damaging the ears of corn.</p> <p>One major benefit of the original design was that the universal joints provided a degree of flexibility, compensating for varying dimensions of the corn cob. To maintain this benefit, A&amp;K designed and patented a motor mount that lets the entire motor and shaft flex according to the diameter and curvature of each cob.</p> <h3>Call it a Success</h3> <p>As before, when a cob becomes lodged or breaks off in the cutter head, a sensor instructs the programmable controller to simply reverse the rolls. Unlike mechanical drives, though, the hydraulic motors accommodate repeated reversals without additional wear or damage.</p> <p><img alt="Fig. 4" src="/site-files/hydraulicspneumatics.com/files/uploads/2016/06/06/Ag-Fig-4.jpg" style="width: 595px; height: 390px;" title="Six geroler-type hydraulic motors plumbed in series drive the six rotating rolls in the de-kernelling station. The geroler motors provide an extremely compact drive that transmits low-speed, high torque power and synchronized motion." /></p> <p>After Anderson and Kessler built the first redesigned machine, they conducted tests that were far more abusive and aggressive than would be found in actual working conditions. The machine went through 20 million cycles without a single problem. Kessler admitted that he doesn&rsquo;t know what the machine&rsquo;s lifetime is: &ldquo;At that time [after 20 million cycles], we said, &lsquo;Let&rsquo;s build it,&rsquo; because it was the equivalent of three processing seasons. So, we&rsquo;re boasting that we have three to five seasons; but we may have more than that before any maintenance would be required.&rdquo;</p> <p>An unexpected side benefit of the hydraulics is higher speed. The A&amp;K corn cutter can de-kernel between 100 and 115 cobs per minute (100,000 to 115,000 lb/day), with a case yield greater than that provided by competitive units.</p> <p>Thanks to their innovative design, A&amp;K now holds a major part of the business of food processing plants in more than 25 countries throughout the world.</p> <p><em>Looking for parts? Go to&nbsp;<a href="http://www.SourceESB.com" target="_blank">SourceESB</a>.</em></p> <table border="0" cellpadding="0" cellspacing="0" width="570"> <tbody> <tr> <td width="41"><img src="http://insidepenton.com/electronic_design/adobe-pdf-logo-tiny.png" /></td> <td style="padding-left: 0px;" width="459"><a href="/datasheet/corn-processing-hits-new-speeds-hydraulics-pdf-download">Download this article in .PDF format</a><br /> This file type includes high resolution graphics and schematics when applicable.</td> </tr> </tbody> </table> </div> http://hydraulicspneumatics.com/hydraulic-pumps-motors/corn-processing-hits-new-speeds-hydraulics#comments Hydraulic Pumps & Motors Mon, 06 Jun 2016 20:54:00 +0000 38531 at http://hydraulicspneumatics.com Corn Processing Hits New Speeds With Hydraulics (.PDF Download) http://hydraulicspneumatics.com/datasheet/corn-processing-hits-new-speeds-hydraulics-pdf-download <div class="node-body datasheet-body"><p>Ron Anderson and Tom Kessler, co-founders of A&amp;K Development Co., Eugene, Oreg., had plenty of ambition when they formed their company. Both had experience in the food processing industry and...</p> <p><strong>Register or sign in below to download the full article in .PDF format, including high resolution graphics and schematics when applicable.</strong></p> <div class="gatedLogin well"> <div class="contentPadding clearfix"> <h2>Register for Complete Access (Valid Email Required)</h2> <p><p><img height="auto" src="http://hydraulicspneumatics.com/site-files/hydraulicspneumatics.com/files/uploads/2015/08/full-wallchart.JPG" width="100%" />By registering on Hydraulics &amp; Pneumatics now, you&#39;ll not only gain access to , you&#39;ll also receive a complimentary copy of <em>Hydraulics & Pneumatics Wall Chart</em>.</p> </p> <div class="gatedLoginButtons gated-register-button"> <div class="button-region"> <a href="/penton_ur/nojs/user/register?source=gated&nid=38541&regmode=1" class="ctools-use-modal btn btn-branded btn-wide ctools-modal-register" title="Register at this site.">Register</a> </div> <div class="loginLinkText"> Already registered? <a href="/penton_ur/nojs/login" class="ctools-use-modal ctools-modal-log_in" title="">Log In</a> here. </div> </div> </div> </div> </div> Gold Mon, 06 Jun 2016 20:50:00 +0000 38541 at http://hydraulicspneumatics.com