NPSHR value for piston pump 1

[Badjuz]

Hi all,

Can anyone help to determine NPSHR value of piston pump, duplex type, double acting, 70 rpm, 4in piston diameter.
Thanks all.

Badjuz

 

[LittleInch]

Established by the vendor.

Usually quite low (2-3m) but it's not something you can calculate, only test.

Piston pumps also need to consider acceleration pulses in the inlet line.

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

 

[Artisi]

From memory this has been discussed msny times here, suggest you search for info .

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.)

 

[bimr]

In a Positive Displacement Pump, NPSH varies as a function of flow determined by speed. Reducing the speed of the Positive Displacement Pump pump, reduces the NPSH. Suggest you contact the pump manufacturer.

Thread

 

[Badjuz]

Thanks all.

Actually we'd like to relocate pump unit.
However for this old pump, the documentation is missing.
Of course for NPSHA and acceleration head we can calculate.
We still search for NPSHR value.
If anyone have experience of NPSHR with similar or close size of pump, this will be helpful.

 

[LittleInch]

70 rpm is pretty slow.

My guess is not more than 4m

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

 

[georgeverghese]

Configure this system without relying on the suction dampener to reduce acceleration loss - all the dampener really does is to attenuate the pulsations to some extent, even when it does work well. At the least, get a triplex double acting to cut down acceleration loss. Cheapo duplex will almost surely get you into trouble with Operations Dept,unless you have plenty of NPSHa.

 

[LittleInch]

How much NPHHA so you have?

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

 

[saplanti]

I guess the following can give you that you are after.

https://pdfs.semanticscholar.org/2083/ceb0f41d96cccf277e0defff6e324ffdc594.pdf

 

[saplanti]

This might be another one.

https://jensapardi.files.wordpress.com/2010/03/reciprocating-pump-manual-1.pdf

 

[LittleInch]

Some great info there.

From the first one 70 rpm is 3 psi for the biggest plunger. So about 2m.

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