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POSITIVE DISPLACEMENT PUMPS

POSITIVE DISPLACEMENT PUMPS

POSITIVE DISPLACEMENT PUMPS

(OP)
Hi all,
one question,
Why do some positive displacement pumps NOT require a pulsation damper?

RE: POSITIVE DISPLACEMENT PUMPS

Pumps don't care if they have a pulsation damper. System designers or system users may.

Ted

RE: POSITIVE DISPLACEMENT PUMPS

There are many types of PD pump mainly into 2 categories based on the pumping action

1) Rotary type such as..twin and multi screw, progressive cavity, gear , lope

2) Reciprocating..plunger , piston

Most rotary PD pumps do not need pulsation dampener because of the very low or almost zero pulsation flow.

Please Google for the various pump type to understand their pumping action and see for your self why a pulsation dampener is needed in a system with reciprocating PD pumps.

RE: POSITIVE DISPLACEMENT PUMPS

this may be off-topic. But as a general rule, does the NIPR of a PD pump INCREASE as the pump becomes older. Let's say we have a 20 year old PD pump with a certain NIPR, wouldn't the NIPR be greater due to the internal parts wearing down?

RE: POSITIVE DISPLACEMENT PUMPS

NIPR? What is that?

RE: POSITIVE DISPLACEMENT PUMPS

net inlet pressure required...

RE: POSITIVE DISPLACEMENT PUMPS

nucleareng78, I had not heard of that general rule. It would seem that as a pump wears, net delivery would be reduced therefore less fluid is delivered and less requirement for inlet pressure to push fluid into the pump inlet. Just the opposite, in theory.

Ted

RE: POSITIVE DISPLACEMENT PUMPS

Maybe there's confusion with NPSHr?

RE: POSITIVE DISPLACEMENT PUMPS

NPSHr is basically the same as NIPR, but PD pumps primarily using the NIPR terminology.

NIPR (psi)
NPSHr (ft WC)

Different units

RE: POSITIVE DISPLACEMENT PUMPS

only pump that have pulse like (AODP, peristáltic, etc...), pump that use screw, gear, lobe don't need pulsation dumper because normaly work with laminar flow.

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