HI friends :
hi friends:

when i want measure cavitation or turbulence conditon in pumps ,where i must put my seismic probe ?

is there article describe this subject ?i will be gratefull to give me this link.


best regards

Where you suspect the source is originating from? I like to start by evaluating the system and pump curves. Are you operating where you should be? Regarding your specific question, depending on the specific speed (i.e.design of the pump) some pumps may only like to operate at its BEP, or not far from it. Large deviations from that flow condition can lead to cavitation or turbulence.
Majority of time, cavitation occurs at the inlet of the pump, so seismic probe on the casing near inlet will give you good results. Move it around to check sensitivity. If you suspect a piping problem (sharp pipe bends at inlet or outlet for example), you may develop turbulence. So place the accel accordingly.
Check overall levels (cavitation and turbulence usually just adds broadband noise - impacting events as bubbles collapse) as a function of flow rate.
Hope this helps
Regards
Jim P

Try this link to the Update International website. Scroll down until you find the section on pumps.

http://www.update-intl.com/VibrationBook.htm

At times the pump crve data is not readily available. I place the Probe on the volute or casing, an area nearest to where cavaitation is suspected. The I go back to the PD and do a spectral comparison - Erratic and high spectral floor.

R,
Dan

Cavitation and turbulence are not the same phenomenon.

Walt

Walt is exactly right. "Cavitation" is a very specific condition that involves bubbles forming and collapsing on the impeller surfaces, usually due to inadequate suction pressure (head). It can be very destructive and often shows up as erosion of the impeller surfaces.

"Turbulence" is much more common (cavitation is actually pretty rare) and usually shows up as "noisy" flow. Some pumps will run noisy, even with a perfectly designed system. Such pumps can be very hard to monitor until you have a lot of experience with them.

Don't know about the rest of the world, but here cavatation is popular. We tend to put in pumps way oversized or try to increase production so they are never on the curve. Cavitation excites all the frequencies and shows up as white noise throughout the spectrum. I have seen impellers eaten completely away from cavitation.

Gary B