3 replies to this topic

Hi,
Two centrifugal pumps of same specification (50 m head, Q= 100 cubic meter per hour) are installed parellely with common delevery. NRV is not there in delivery of both the pumps.

What would be the effects of this on Pump?

[Art Montemayor]

I don't understand your intent in asking this question.

• Is this an academic question, requiring a simple theoretical answer?
• Is this an existing, industrial application? If so, is it working OK? Or is it giving problems?
• Is this a practical, proposed industrial application?
• Is this a personal, conceptual idea that you want to expound?
• Is this a test?

I'm going to assume you are simply curious and are asking this simply to satisfy your need to know from a conceptual point of view. My answer is that nothing happens to either pump or to their expected pumping ability - if all other factors are taken care of and engineered accordingly.

A check valve - on either the suction or the discharge side of a centrifugal pump - is not a mandatory requirement for a centrifugal pump to do its job. It helps out, and is smart engineering (in my opinion) to install one in either side. But it is not a requirement.

Please note that I am not addressing the fact that you probably will inherit operating, startup, shutdown, and maintenance problems if you don't install a check valve. You didn't ask that.

For an idea of what could happen, read my response to another query, at:
http://www.cheresour...amp;#entry17446

[srtools1980y]

Hi!
if only 1 pump is active wat will happen?
goodday
srt.

[Zauberberg]

If stand-by pump is with a blocked discharge (as it should be the case), nothing can happen. As a matter of fact, heavy petroleum distillate pumps usually have small bypass from discharge line around NRV and discharge gate valve to ensure backflow of small amount of process fluid through the casing of pump which is in stand-by mode, in order to supress solidification within the pump casing. This way, the pump that is working provides heating of the stand-by pump.

As Mr Montemayor said, NRV is not a mandatory. But it is really good to have one at each pump discharge line - both from operational, maintenance and safety reasons.

Regards,