Flow Switch in Pump Suction
Flow Switch in Pump Suction
(OP)

Process and E&I are developing P&IDs for an upcoming project. The picture I've attached shows the preliminary drawing they have come up with. As I'm sure we all know by now, concentric reducers should not be used in pump suction lines unless the pump is a top suction pump, which this one is not. I've brought this point up to them along with discussing cavitation, but as of now they are not wanting to change what they have come up with. Their reasoning being the line size is too small for the flow switch insertion into the pipe and they want the flow switch to protect the pump (obviously).
Before I go back and argue some more, I was looking for some reinforcement that I should continue this argument and look for an alternative solution.
The pump will be used for offloading tanker trucks with refinery grade propane and sending it off to bullet storage tanks.





RE: Flow Switch in Pump Suction
Any chance the flow switch segment could be located on vertical without decimating your NPSHa?
RE: Flow Switch in Pump Suction
I do not foresee there being any vertical piping on the suction to locate the switch.
RE: Flow Switch in Pump Suction
1, On your sketch there are three "branch" line indications with arrow heads. What are these please?
2. What is the purpose of the Flow Switch?
Sometimes its possible to do all the right things and still get bad results
RE: Flow Switch in Pump Suction
RE: Flow Switch in Pump Suction
The two bottom branch lines tie together and run to the flare.
The top branch line is a bypass that runs to the pump discharge in case the tanker truck pumps are used.
RE: Flow Switch in Pump Suction
RE: Flow Switch in Pump Suction
RE: Flow Switch in Pump Suction