Selecting pneumatic equipment
Because it is cost effective and easy to maintain, pneumatics is ideal for food processing applications where washdown is a consideration. When using pneumatics in food applications, it is important to:
• Select the right product for each application — various products suit different needs.
• Mount the valves close to the cylinders to keep cylinder motion synchronized with the valves.
• Mount the cylinders so they can be easily cleaned.
• Decentralize valve manifolds on larger production lines.
• Dimension pneumatic systems for optimal performance.
• Ensure the air pressure is constant to maintain optimal actuator cushioning by placing the regulators close to the actuators.
• Filter the compressed air according to the applications for which it is being used. If possible, place filters by each valve manifold.
• Use food grade lubrication. Lubrication is generally not needed but, if it is used, it must be food grade (type NSF H1), and
• Involve your technology supplier from the beginning of the project to get the correct solutions for each application.
Industry gives a rating, such as IP65, to pneumatics components based on particle tight design and watertight design — the first number is the dry particle rating and the second number is the wet test rating. Bosch’s IP69K-rated pneumatic valves, such as the Clean Line Valve (CL03), withstand pressurized water and steam damage. To meet the IP69K rating, valves withstand pressure of 1450 psi at a distance of 4-6 in., with water (at a temperature of 80° C) flowing at 14- 16 in./min while the object is rotated between 0°, 30°, 60° and 90° angles. (For comparison, IP65 enclosures cannot allow dust to enter and a jet nozzle splashes a volume flow of 12.5 lpm from a distance of 2.5-3 m.)
Pneumatic actuators are also used in sensitive washdown applications and with parts that are in direct contact with food. If applied incorrectly, pneumatic actuators can act as bacterial pumps, so it is important to ensure they are fitted properly. For harsh washdown applications, cylinders may contain rounded corners for easy drainage, positive sealing, “male” cushion-screw, clean cylinder-noses, and food grade lubrication.
According to Hughes, “Ours is a washdown environment. We have to assume everything we use is going to get a bath every day. A lot of valve companies in the industry claim to have IP65 products, which means the valve can handle hose-directed water. Our experience has been that the IP65 components really don’t work as well as some manufacturers claim they do. With the Clean Line products from Bosch Rexroth, the design is specifically IP69K, which is extremely watertight. All the surfaces are either plastic or stainless steel, so you don’t get any corrosion from cleaning chemicals, versus other valves that use aluminum or some lesser metals that would corrode.”
For washdown and sanitary food applications, pneumatics applications provide effective prevention against contamination while maximizing operational costs, guaranteeing food quality and improving production capacity. No matter what equipment is chosen, the key points to remember are it must be easy to clean and maintain.
While a box of chocolates left out at work may disappear extremely fast, the production of fine chocolates and confectionery is timeconsuming, not to mention expensive.
Nevertheless, the demand for sweet delicacies has been growing for years. Carle/Montanari SpA, Rozanno, Italy, has developed a refining machine that makes it possible for the confectionery trade to save on costs and continue to improve the quality of its chocolates.
The HFE-518 refining machine for processing and refining bulk chocolate makes on-going quality monitoring possible. Any deviations in relation to quality are automatically corrected during the manufacturing process by changing certain settings. Once the raw mixture has gone through the HFE-518, it turns into an interim product — the finest powdered chocolate.