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Help Identifing the Cause of this Noise

Help Identifing the Cause of this Noise

Help Identifing the Cause of this Noise

We have a test assembly and it is making a loud whinning noise.

It has a powerpack driving fluid through a valve (load) and then the oil cooler (also a filter)

I think the valve may be vibrating (seat), or maybe the fluid is aerating?

Any suggestions?

RE: Help Identifing the Cause of this Noise

Which part are you testing?


Mike Halloran
Pembroke Pines, FL, USA

RE: Help Identifing the Cause of this Noise

we are testing the electronics that drive the pump.  I don't know much about the assembly.  

The pump is driving at 3200 rpm, and has 2cc/rev.

Temp is room to about 120C

High Pressure is 1300+/-100 psi

the load is a pressure relief valve - Vickers RV1-8-S-o-36

Thanks again.

RE: Help Identifing the Cause of this Noise

That appears to be a direct acting poppet type relief valve in a screw-in cartridge.  I couldn't find enough info to decode the full part number, but that helps a little.

You should know that _any_ pressure control valve is just abut guaranteed to oscillate, absent some internal damping.

The internal damping mechanism may not be obvious; it's often a closed cavity with clearance its only opening, or perhaps a small orifice.

The important point is that the cavity may not bleed itself right away, or ever, and if it has air in it, it won't work.

Try pre-bleeding the relief valve by immersing it in a cup of oil in a bell jar, then evacuating the jar and holding the vacuum until the bubbles stop.  Then put the cartridge back in the assembly.


Mike Halloran
Pembroke Pines, FL, USA

RE: Help Identifing the Cause of this Noise

Please check the leaks. I had similar problem in a water line and was much louder than this. The clamp or gasket in case of bigger lines usually makes this type of noise as well

RE: Help Identifing the Cause of this Noise

At that speed the pump is not going to be very quiet.

It will make a high pitched whining noise.

If oils is flowing across the relief all the time the relief will also make noise.  The RV1 relief is a Modular controls type valve that is a direct acting poppet relief, These make a lot of noise when they are functioning.

If you need a quieter relief, go to a pilot operated type relief.  but it may not fit in the same cavity.

This is very difficult to troubleshoot because everyones definition of noise is different, and not sure what type of a circuit you are playing with.

Good luck!


Tom Nelson
Application Engineer (CFPS)
CATCO Parts and Service
St Paul,MN

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