Plunger Pump Inlet Size
Plunger Pump Inlet Size
(OP)
Dear All,
Happy New Year.
I am installing a small plunger pump (CAT 230 with variable speed drive) to pump water at low flowrates into a pressurised steam line in our R&D test facilities.
Reading the installation manual it states that the inlet line size must be a minimum of one size larger than the pump inlet fitting (1/2") to avoid cavitation.
How critical is this? I have bought all my fittings in the same size as the pump inlet (1/2"). Will I get cavitation damage by having the inlet piping the same size as inlet. My flow range is 40-200lph (pump capacity 500lph) and pressure range 5-50barg (max capacity 105barg).
Also is it OK to fit a non return valve 1 meter downstream of the pump (outlet line size 1/2").
Many thanks in advance
Andrew
Happy New Year.
I am installing a small plunger pump (CAT 230 with variable speed drive) to pump water at low flowrates into a pressurised steam line in our R&D test facilities.
Reading the installation manual it states that the inlet line size must be a minimum of one size larger than the pump inlet fitting (1/2") to avoid cavitation.
How critical is this? I have bought all my fittings in the same size as the pump inlet (1/2"). Will I get cavitation damage by having the inlet piping the same size as inlet. My flow range is 40-200lph (pump capacity 500lph) and pressure range 5-50barg (max capacity 105barg).
Also is it OK to fit a non return valve 1 meter downstream of the pump (outlet line size 1/2").
Many thanks in advance
Andrew





RE: Plunger Pump Inlet Size
A downstream check valve should be OK.
BigInch
-born in the trenches.
http://virtualpipeline.spaces.msn.com
RE: Plunger Pump Inlet Size
Will NPSH be a problem for me because I have a plunger pump that will be fed pressurised water from a centrifugal pump in the basement (I am using the plunger pump to boost the water pressure). My plunger pump recommends an inlet pressure of 1.4barg (max 4barg). I will have a pressure gauge on the inlet and can adjust the inlet P accordingly.
Thanks
Andrew
RE: Plunger Pump Inlet Size
RE: Plunger Pump Inlet Size
RE: Plunger Pump Inlet Size
You may want to take a closer look at the centrifugal pump that you are using to feed this plunger pump. Is anthing else being served by this centrifugal pump? Where will it be operating on its performace curve? Will it always be assured of an adequate minimum flow? Is there some sort of receiver tank involved? An arrangement such as you plan can work, but nasty little problems can crop up without adequate attention to all details.
If I'm correct, this is a triplex pump, so the fluid accelerations should not be too great, but if the suction line is relatively long, it would be wise to install an accumulator adjacent to the pump suction. I almost always install relatively large accumulators at the suction of such pumps just to minimize vibrations and needless wear.