VIBRATING CONDENSER WATER PUMP

[GraemeJ]

I have inherited a project, where chillers were upgraded, requiring the condenser water pumps changed. The new pumps are rated at 250 litres/sec @ 400kPA.

Some modifications were carried out to fit the pumps at the suction and discharge pipework. The pump was mounted on the old inertia base. When the pump was run it began to vibrate badly. The pump motor shaft alinment was checked and the balance checked by the manufacturer. The problem still exists.

Is cavitation a likely problem?

 

[Kailee]

Do yourself a favour and have a proper vibration analysis done. Saying the pump now vibrates badly does not tell anyone anything signifigant.

A vibration analysis will give you the information you need to properly diagnose and then correct the problem.

Hope this helps.

Cheers!

 

[electricpete]

One starting point would be to know what is the frequency of vibration.

Broadband vibration would generally point towards cavitation or turbulence.

1X running speed vibration would generally point towards unbalance, misalignment, possibly other things.

Blade pass frequency vibration points to another set of considerations.

If the vibration is directional, we may suspect a resonance. Sometimes may be evaluated with a bump test.

Also critical speed of the machine should be considered. Evaluate it with a coastdown test.

This is just a start. I agree as mentioned above there are many possibilities.


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[pmkPE]

call in the representative for the manufacturer of the pump. they shouold be able to do a quick evaluation of the problem without charge to you or your client. They should also be able to refer you to several text books on pumps and their configurations for optimum performance.