Hydraulic Pressure Problem 11

[dik]

We have a large hydraulic system that is running at 1550 psi. When the hydraulic ram is extended, there is a significant vibration at about 4-5 cycles per second. The system is powered by electrical motor and pump and it doesn't seem that there is any noise.

Is it possible that air in the system is causing this? or perhaps some form of 'water hammer'? The system also has a pressure relief valve; is it possible that this is causing the vibration?

Dik

 

[dik]

Is it possible to determine the 'roughness' of a cylinder or seal by means of a 'sound sensor' type of equipment (maybe a stethoscope (sp?) or something of that ilk)?

The ram is stationary and the cylinder moves and because it is double acting, it is not readily possible to examine the seals and/or the cylinder.

Dik

 

[EdDanzer]

You may be able to test for excessive clearance chatter by measuring radial movement extended and retracted. If you know how the piston is held to the rod there may be a way to determine if the piston is loose by looking in the blind end port with a bore scope. The bore scope could see down the barrel a ways to see if there is poor surface finish causing problems.

Ed Danzer

http://www.danzcoinc.com

http://www.dehyds.com

 

[MikeHalloran]

If a cylinder with a 22" bore drops an inch when you turn off the pump, that suggests that there is a check valve holding it up, and the check valve is passing about 1.65 gallons of fluid backward before actually seating.

Which suggests that the check valve is sticking or otherwise messed up.





Mike Halloran
Pembroke Pines, FL, USA

 

[limey1]

I am assuming with the volume of fluid required to actuate the ram, you would be using more than one proportional valve. If this is the case, are the valves opening/closing at the same time, and at the same speed?