pH and abrasives effects on choosing pump construction
pH and abrasives effects on choosing pump construction
(OP)
We have several self-priming stainless centrifugal pumps that have been running for 15 years and have given us very little trouble. I do not have nuts and bolts flying into the impeller, but I do have a Manganese Dioxide powder as well as plastic pellets (and the occasional plastic trash in any wastewater system). We treat this wastewater for pH, hence the pH can swing from 6-9, rarely as low as 4 and sometimes as high as 10 or 11. What material of construction would be most appropriate here since I need to upgrade these pumps? My first thought is to go with what has worked for years, however, if I can save some money by going with ductile iron or carbon I would prefer that route. The flow is ~180 GPM @86 FT TDH.
Also, in order to improve my NPSHA (suction pressure is only 7-8 PSIA)would moving the suction strainer to the discharge be unwise in that I could plug/ruin the impeller/pump?
Also, in order to improve my NPSHA (suction pressure is only 7-8 PSIA)would moving the suction strainer to the discharge be unwise in that I could plug/ruin the impeller/pump?





RE: pH and abrasives effects on choosing pump construction
15 years pumping the crap you are is a long time. It ain't broke........
RE: pH and abrasives effects on choosing pump construction
Suction strainers are called that for the obvious reason. If NPSHa is a problem, can the pump elevation or the suction pipe size be changed?
RE: pH and abrasives effects on choosing pump construction
RE: pH and abrasives effects on choosing pump construction
The 12-14 ft NPSHr probably represents pump operation with 3% head loss to cavitation, so operation at 16 NPSHa does not present much of a favorable margin. I would want to consider other pumps and system configurations if possible.
RE: pH and abrasives effects on choosing pump construction