External PSV required when Internal available
External PSV required when Internal available
(OP)
We have a PD pump with internal PSV. Relieves from discharge back to suction. Set at 125#.
Is an external PSV required on the discharge of the pump? Process engineers are saying that if the internal PSV opens up for a period of time, that temperature will build up and it needs to be relieved, requiring an external PSV. External PSV would be piped back to the tank.
I agree that temperature may build up, but what will the additional PSV do that the internal already isn't doing?
Is an external PSV required on the discharge of the pump? Process engineers are saying that if the internal PSV opens up for a period of time, that temperature will build up and it needs to be relieved, requiring an external PSV. External PSV would be piped back to the tank.
I agree that temperature may build up, but what will the additional PSV do that the internal already isn't doing?
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RE: External PSV required when Internal available
Regards,
SNORGY.
RE: External PSV required when Internal available
RE: External PSV required when Internal available
RE: External PSV required when Internal available
RE: External PSV required when Internal available
The internal releif in an ebsray sliding vane pump is similar in configuration to a standard PSV, but the set point can easily be changed.
If recycling and temperature build up is considered a problem, then add a temperature switch and shutdown
RE: External PSV required when Internal available
After several overpressure incidents on the discharge I discovered the
internal valve was rated for significantly less than total pump flow.
I later discovered the relief valve intension was to balance pressures across shaft bearings.
Moral: Find out the intension of the internal relief.
I think you will find an API standard - any pump 15-hp motor or greater must have an external relief valve.
RE: External PSV required when Internal available
Would you point out where in API that specify a 15-hp motor or greater must have an external relief valve?
Thank you,
Sharon