I am faced with a situation where I want to sap up 280GPM of over flowing water. Problem is there is an existing pump that operates at 1122GPM @ 40 PSI. I wish to use a smaller pump to parallel with the present pump. My system is not equiped with variable speed drives, I use autotransformer...
Gentlemen thanks for the assistance, I have found the problem, the limiting factor is the NPSHA. The NPSH requirement above 300m3/h is 53ft. The pump is set at 9ft below the water surface, adding the 33ft available plus 9ft (42ft). So it obvious that there is a short fall in in the NPSHR.
In response to all the comments made so far, the impeller is of the closed type, the rotation is correct (CCW), the pumping fluid is water, the impeller was place in a dummy bowl which was already on the turbine, so the pump length did not change, the current is well within the full load...
I will agree with you TD2K I was expecting an increase in flow with the additional stage, that's the reason the stage was added. I am sure that nothing was left in the pump during fitting up. With the additional head do you thing the NPSHR might have changed and is now insufficient? Please note...
Can anyone tell me why after increase the stage of a 10inch vertical turbine pump from 3 to 4 stages the flow fell from 288 m3/hr to 240m3/hr (1500RPM)instead of increasing. Please note the pump is operating in the same system. The system of operation is pumping directly inline.
Can anyone tell me why after increase the stage of a 10inch vertical turbine pump from 3 to 4 stages the flow fell from 288 m3/hr to 240m3/hr instead of increasing. Please note the pump is operating in the same system. The system of operation is pumping directly inline.
I am asking anyone out there who knows and can assist me with the issue of NPSH required for a vertical turbine pump. I know how it is calculated and all that. What I need to know is if the requirement changes with each additional stage of the pump. Is it that the requirement given for one stage...