Liquid Dynamics International Ltd. - Piping System Analysis / Piping System Simulation

LDi – P9

Suction side pulsation
The answer - 2 do's and 2 don'ts

"Started" for reciprocating pumps means each suction stroke.

Suction supply system instability is easier to prevent than to allow and try to cure.

1. Provide the pump with a local source of volume at minimal pressure so that the mass to be accelerated is negligible. The volume must be able to change without a pressure fall.

2. Interceptors are “close coupled”
De-couple the supply column from negative pressure changes
De-couple = intercept by pass-through plus direction change.

Local suction volume elasticity is an essential.

1. Do not force gasses into solution with nitrogen or air pads, they will come straight out when the pump starts and increase the instability discussed in the problem.

2. Do not insert orifices or restrictions they will cause wave rebounds at a higher frequency, and cause frothing.

Orifice – makes bubbles
Flow controls
Restriction – choke the flow