Hydraulicspneumatics Com Sites Hydraulicspneumatics com Files Uploads Custom Inline Archive Www hydraulicspneumatics com Content Site200 Articles 07 01 2011 87633clampingsy 00000060298
Hydraulicspneumatics Com Sites Hydraulicspneumatics com Files Uploads Custom Inline Archive Www hydraulicspneumatics com Content Site200 Articles 07 01 2011 87633clampingsy 00000060298
Hydraulicspneumatics Com Sites Hydraulicspneumatics com Files Uploads Custom Inline Archive Www hydraulicspneumatics com Content Site200 Articles 07 01 2011 87633clampingsy 00000060298
Hydraulicspneumatics Com Sites Hydraulicspneumatics com Files Uploads Custom Inline Archive Www hydraulicspneumatics com Content Site200 Articles 07 01 2011 87633clampingsy 00000060298
Hydraulicspneumatics Com Sites Hydraulicspneumatics com Files Uploads Custom Inline Archive Www hydraulicspneumatics com Content Site200 Articles 07 01 2011 87633clampingsy 00000060298

Hydraulically-controlled clamping system losing pressure in steel mill

July 14, 2011
Hydraulically-controlled clamping system losing pressure in steel mill Appeared in print as "Clamping system losing pressure" A steel mill has four identical hydraulic systems that perform the same function. When the cylinders extend to a clamp ...
Hydraulically-controlled clamping system losing pressure in steel mill

Appeared in print as "Clamping system losing pressure"

A steel mill has four identical hydraulic systems that perform the same function. When the cylinders extend to a clamp position, one system seems to slow down with a drop in pressure for a short time, and then the pressure climbs back to minimum pressure needed to do the work. The other three systems stroke quickly without the pressure dip experienced by the one problem unit.

Maintenance checked the gas precharge on all four piston accumulators and confirmed they were all close to 500 psi. They made sure all the accumulator bleed down valves were open and had drained all the hydraulic pressure from the systems.

When running and when idle, all four systems would cycle on and off as you would expect with accumulator unloading circuits as shown in the circuit. When pressure reached 1100 psi, the unloading valve would open completely, allowing the pump flow to free-flow back to tank with very little backpressure.

When the accumulator’s hydraulic pressure dropped about 15% to 17%, the unloaded pressure control would snap closed. This forced the pump flow to enter the accumulator circuit until pressure reached 1100 psi, then the pressure control would unload again. The problem circuit seemed to cycle more frequently than the others.

All four cylinders were isolated from the system and checked for internal leaks. One of the cylinders that worked well had a small by-pass, but it did not affect the needed cycle time. They installed flow meters and all four pumps checked out as being in good condition.

Any ideas about the cause of the problem?

Find the solution

Think you know the answer? You can submit solutions by e-mailing [email protected]. We will also post this problem at forums.hydraulicspneumatics.com/groupee, under the Editorial Comments section. Answers can be posted there as well.

All correct solutions will be entered for a chance at a $50 gift card — we will randomly select a winner from all correct answers. The winner will be notified and his or her name will be printed in the August issue.

The correct answer will be published in the next edition of “Troubleshooting Challenge,” and also at forums.hydraulicspneumatics.com/groupee.

Continue Reading

BOOK 2, CHAPTER 12: Fluid Motor Circuits

March 18, 2009
Table of Contents

Motor leakage variations

Oct. 18, 2006
affect low-speed performance

Sponsored Recommendations

7 Key Considerations for Selecting a Medical Pump

Feb. 6, 2024
Newcomers to medical device design may think pressure and flow rate are sufficient parameters whenselecting a pump. While this may be true in some industrial applications, medical...

How Variable Volume Pumps Work

Feb. 6, 2024
Variable volume pumps, also known as precision dispense pumps, are a positive displacement pump that operates by retracting a piston to aspirate a fluid and then extending the...

What is a Check Valve and How Does it Work?

Feb. 6, 2024
Acheck valve, a non-return or one-way valve, is a mechanical device that allows a gas or liquid to flow freely in one direction while preventing reverse flow in the opposite ...

The Difference Between Calibrated Orifices and Holes

Feb. 6, 2024
Engineers tasked with managing fluid flow talk about both holes and calibrated orifices, but they are two distinct entities. A hole can be any opening, but a calibrated orifice...