Vibration 1.7X Pump

[garciaf]

Help with these Issue.
about Vibration Analysis
See PDF attachement.
Thanks.

1 stage Pump
Fluid pump: Crude Oil.
Centrifugal Horizontal Pump
INGERSOLL DRESSER RAND
RPM: 3540 rpm
Type: 4HPX
Model: HPX
Serie: P-58106-02
Flow: 890 gpm /30514.27bd
Motor: Reliance
Potencia:250 hp
Amperaje:269 amps

Variables operativas actuales:
Suction pressure: 140 psi
Discharge pressure: 390 psi
SG: 0.77
Temperature: 300F
Flow: 408.33 GPM (14000bd)

 

[Artisi]

Pump curve available?

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[LittleInch]

Well it looks like double the rpm so maybe blade pass? Or something hitting the casting twice per revolution.

Your flow is quite low compared to duty point. Can you try at a higher flow?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[JJPellin]

I have seen similar vibration on a pump in light coker gas oil service. We upgraded the pump with a back pull-out assembly and the vibration was resolved. I believe it was a result of a structural resonance excited by chronic cavitation from operation too far below best efficiency point. I have attached one of the ODS animations of our pump.

Johnny Pellin

 

[garciaf]

PUMP CURVE OF PUMP

 

[JJPellin]

I am estimating the suction specific speed somewhere above 13,000 (US units) depending on how close this impeller is to maximum diameter. Given the shape of the curve and the relatively high suction specific speed, this does not look like a pump that is going to have good reliability running down at flows that low. I believe that this model can be purchased with an inducer screw. Does your pump have an inducer?

Johnny Pellin

 

[garciaf]

Do not have inducer

 

[LittleInch]

Something is a little odd in the differential pressure on the curve but not majorly out - 30 or 40 psi

But yes, a bit low down the pump curve for good operation.

Also you're in a very flat bit of the curve - is your flow steady or does it go up and down ?

Can you try it at different flow rates?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Artisi]

You seem to be operating somewhere off curve, as pointed out by LittleInch - where is the excess head that the pump can develop going?

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)