Fluid Power Journal

New Problem Servo System Pump Keeps Failing

By Robert Sheaf, CFPAI/AJPP, CFPE, CFPS, CFPECS, CFPMT, CFPMIP, CFPMMH, CFPMIH, CFPMM
CFC Industrial Training

A company that manufactures plastic bottles for suppliers of motor oil started losing pressure-compensated pumps weekly on one of four identical units. The system used a servo valve for controlling a cylinder that had to maintain a position very accurately, and both oscillated continually. They could not understand why three units worked fine but one gave them problems.

The 5-gpm (19-lpm) pumps were internally grenadeing. After each failure, they cleaned the entire system of debris, changed the filter elements, inspected the case line for broken pump parts, and installed a new intake-line hose, but they were still losing pumps on an average of one a week, a total of four pumps when I was called into help.

What could be causing the problem?

Robert Sheaf has more than 45 years troubleshooting, training, and consulting in the fluid power field. Email rjsheaf@cfc-solar.com or visit his website at www.cfcindustrialtraining.com.

Share this information.

Related Posts

One thought on “New Problem Servo System Pump Keeps Failing”

  1. Michael Fulchini says:

    Was the pump outlet check valve broken? Maybe accumulator or bore of cylinder decompressing thru pump and blowing the shoes off the piston? O-ring holding open check valve?

Leave a Reply

Your email address will not be published. Required fields are marked *