Do the pumps have a common discharge header. For some reason pumps, #2,3, are running left to the design point. Less flow and more head, Plot the curve from the running points to the design points. This will tell you wheather or not the pumps are capable of running @ design point. this should...
I suppose the knowledge base of pump companies dwindles as much as all other fields. I have had the good fortune to work with one pump company who wrote the book on sump design. My 2 decade friend and mentor Herman who spent twenty years on the board of the National Hydraulic Institue has...
Designing a sump is more complicated than you think, and nothing will give you more headaches than a bad sump design. Whom ever you are buying your pumps from will be more than happy to supply you with there recommeded parameters. This will be a large sale for them and they will want your...
electricpete,
More seal ring clearance will degrade head, look at any pump curve as the head drops the capacity increases. This however is not good for your pump, recirculation damages.
Pumper
Wear ring clearances are dependent on media, bearing material, wear ring material and the size of the pump.
If the pump is old take into account register clearances.
Your pump supplier should have a chart with standard wear ring / bearing clearances for any size pump, this should include ss on...
What caused the pressure drop, a larger pipe will give you less friction loss, thus increasing pump head. Either the pump was sized wrong, it is out of ajustment (semi-open impeller) or it is worn out at the seal ring (enclosed) Backfiling will increase eff. However it is probably allready...
