Double Suction Centrifugal Pump Vibration
Double Suction Centrifugal Pump Vibration
(OP)
I work in a Paper Mill and one of our Fan Pumps Has developed high vibration readings. The Pump is a Goulds Double Suction Centrifugal Pump 3400 series. It has a Paraflex Coupling. The Pump runs at 1770 RPM. In the past month we have developed high vibration in the pump. Most of the vibration shows up as 1x. The running element was changed out twice and the pump still has the high 1x vibration with little difference noted between running elements. Readings are as follows in veloscity: Motor- MAH.0625ips, MBH-.0941ips, Pump- PCH-1.22ips 6.6ge PCV- .53ips 6.6ge, PDH- .49ips 9.4ge, PDV- .16ips 6.4ge, PDA-.74ips 8.0ge. The FFT's show a large 1x spike and a small 2x spike. Phase readings showed 171'. Recently, last two days, the Paraflex Coupling Insert failed. Does anyone have any ideas of what is causing this vibration to suddenly occur and continue even after changing the running element????





RE: Double Suction Centrifugal Pump Vibration
If I ignore the high gsE readings, I would tend to think of misalignment (possibly pipe strain, thermal growth, soft foot, etc). Things that point to that:
- *coupling insert damage
- 180 degrees phase shift across coupling (What orientation was that?)
- 1x plus some 2x.
- Axial vibration.
Normally I would expect to see some evidence of misalignment on the motor. Did you get vertical and axial readings at the motor?
I'm not sure about the gsE readings. Note that the location of the highest gsE reading does not fall at the lcoation of the highest velocity reading (3H).
Perhaps those gsE levels are normal flow noise for this pump? Do you have any other similar pumps? You might take a quick check for harmonics of bearing fault frequencies. Also a timewavefrom looking for impacts or other things to help determine whether gsE levels are normal or indication of a problem.
RE: Double Suction Centrifugal Pump Vibration
I would have to agree with pete. How was alignment done.!80 deg phase shift across the coupling axially normaly signifies misalignment. Have bearings also been replaced, you may have a "cocked" bearing. do you have a multitude of 1X harmonics. I assume the "running elements" are impellers of some sort. Are they possibly skewed. I this is an overhung type situation, it would give you a high 1X and possible 2X with other variables
Roy Gariepy
Maintenance and Reliability Dept.
Bayer Corporation Dorlastan Fibers Div.
Goose Creek, South Carolina USA
RE: Double Suction Centrifugal Pump Vibration
RE: Double Suction Centrifugal Pump Vibration
to be viewed.
RE: Double Suction Centrifugal Pump Vibration
Have your operating conditions changed in the last month?
Is the motor variable speed?
Are you running at a different point on the pump curve?
Has the consistency of the process fluid changed?
When you check the motor current, is it pulling more amps than before?
RE: Double Suction Centrifugal Pump Vibration
RE: Double Suction Centrifugal Pump Vibration