Review of pump nozzle size

[Balasubramanian Jayaram]

Hi All,

How to review the pump nozzle size given by supplier. Sometimes the suction & discharge nozzle sizes are larger than pipe line size. It is acceptable. Provide any guidance to review the pump nozzle size for both API 610 & API 676.

 

[Artisi]

yes.
what is there to review, the pump design dictates the nozzle size.
Are you asking how best to make the transition from the inlet pipe to the inlet nozzle and outlet nozzle to the discharge pipe?

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.)

 

[Balasubramanian Jayaram]

Hi Artisi,

Ok noted for pump design dictates the nozzle size.

Is pump nozzle size should be less than pipe suction & discharge line size?. Please explain.

 

[LittleInch]

In general, the inlet nozzle (suction) is the same size or maybe one or two pipe sizes lower if the pump is a single pump (i.e. 1x 100%). The discharge nozzle is often one or two pipe sizes smaller than the connecting pipe.

If your pump nozzle sizes are larger then this tends to indicate that the pump is too big for your demand or your pipeline is smaller than normal.

However if the numbers check out then it is acceptable, if a little odd, for the pump nozzles to be bigger than the attached piping.

check out the efficiency of the pump at your duty point compared to other pumps. A big pump operating on the far LHS of the pump curve can be very inefficient.

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

 

[Balasubramanian Jayaram]

Hi LittleInch,

Thanks for the response. It clarifies my doubt.

However is the response applicable for all type of pumps like api 610, 674, 675 676 and etc).

 

[MJCronin]

Balasubra ....

You need to purchase a book on piping system design around pumps...... Lots of information available on the interwebs...

It sounds like this is your first assignment on pumps and piping ...

For Centrifugal Pumps, be aware that:

1) Usually the pump suction piping is one or two pipe sizes larger than the pump suction size. MAKE SURE THAT THE LIQUID VELOCITY IS BETWEEM 3-5 FPS AND THAT THE PUMP NPSHr REQUIRED IS EVALUATED AND RESPECTED !!! Beware of systems with low NPSHa !!!

2) Discharge piping can be the same size or one pipe size larger. If the discharge piping has a check and shutoff valve, make them the same size as the discharge nozzle (no smaller) and place them near the pump.

3) Beware "Double suction centrifugal pumps" ....they have special suction piping requirements.

Positive Displacement pumps have other requirements ..

MJCronin
Sr. Process Engineer

 

[Balasubramanian Jayaram]

Hi MJCronin

Thanks for the prompt response and support. I will purchase the book. Can i have the cover picture of the book which specified above.