15 replies to this topic

[farid.k]

Anyone experience pump vibrate due to wrong/poor/damage pump foundation?
I did checked with checklist provided by mr ankur and other relevent source and non of them mention vibration due to foundation. Mostly due to pump (mechanical parts) damage like bearing, shaft, or operate below npshr, suction has bubble etc. Any comment?

[breizh]

farid.k

 

Probably you know this resource : http://www.mcnallyin...-html/2-09.html

 

Breizh

[farid.k]

Thanks sir for sharing. Currently we have 1 pump that vibrate (on and off). Sometime OK sometime exceed the limit. One of the proposed solution is to relocate the pump which I don't think it can solve the problem as the vibration will not come from the ground or its foundation

[fallah]

farid. k,

 

Have you investigated if the cavitation can be the source of vibration?

[farid.k]

Yes..already considered. Cavitations, bubble trap, npsh. Existing tank is elevated quite high and pump used is vs6 type. By maintaining working level I don't think the npsh will be the issue. Plus the vibration issue comes after 15 Years operation

[breizh]

Hi ,

You may have also gas coming along with the liquid that can lead to cavitation , same for strainer .

 

Breizh

[fallah]

 

farid.k,

 

Then you have to run a "pump vibration analysis"; it probably is among hydraulic, mechanical, piping problems are to be considered as root causes of pump vibration... 
 

[breizh]

farid,

Will it be possible to upload a picture of the equipment ? This may save hundred of words .

 

Breizh

Edited by breizh, 27 March 2016 - 07:05 PM.

[farid.k]

Fallah:

 

piping problem? how can piping can cause pump vibration??

[farid.k]

Breizh:

 

the pump is about 15-16 years old and even i also cant find the datasheet to check the NPSHr value and the pump curve. what can i say is the pump serve for liquid ethylene (cryogenic) and pump type is VS6 pump with discharge pressure around 40 barg.

[fallah]

 

 

 

farid.k,

 

Suction/discharge pipe configuration/strain, either due to the piping design or as a result of thermal expansion,  can always be a root cause of the pump vibration. To avoid such cause of pump vibration some piping practices should be considered in relevant suction/discharge design as follows:

 

-Considering 5-10 diameters of pipe size as straight run before pump suction nozzle

-Using hangers for pipe supports if needed

-Using expansion loop for high operating temperature and large size piping

-Using pipe supports and hangers at unequal distances to avoid pipe resonance and subsequent vibration transfer to the pump
 

[himant]

farid

 

just curious.. is it vibrating at complete range of loads? Is it like less vibration at more load?

[farid.k]

himant, on 28 Mar 2016 - 10:09 AM, said:

farid

just curious.. is it vibrating at complete range of loads? Is it like less vibration at more load?

What do you mean by load?

[Dr.Eng. Mohamed ElAdawy]

Hello Farid:

Really this problem faced us and it lead to change rotor every two days. The solution of the problem, by changing the concrete foundation of the pump after 20 years of operation and so the metal base. The pump in operation now without problem 6 years after changing the concrete foundation.

[fallah]

Dr.Eng. Mohamed ElAdawy, on 01 Apr 2016 - 10:10 PM, said:

 

Really this problem faced us and it lead to change rotor every two days. The solution of the problem, by changing the concrete foundation of the pump after 20 years of operation and so the metal base. The pump in operation now without problem 6 years after changing the concrete foundation.

 

Dear Dr. EIAdawy,

 

Please let's know about the change detail and real issue based on which the foundation required to be changed....
 

[Dr.Eng. Mohamed ElAdawy]

Dear Naser:

The change detail concentrated in change the concrete base for the pump by new one. I think it is very easy for any company. The pump working in acid medium and low PH flow affected on the base with the long time run. Vibration analysis was done and it is show that the fixation system of base need check trying to adjust the base bolts and control the vibration but all efforts fails. Thinking in changing the concrete base of the pump and after that the problem solved.