Piston vs Diaphram

[tjmurf]

We are needeing to replace a 12.25" duplex piston / plunger pump with 4" inlet and discharge. The process in un-screened primary domestic waste sludge. Is this the right pump for the application? How will a diaphram pump compare to a plunger in this application? This is a high grit and solids process.

 

[SteveWag]

The diaphragm pump will be sealed and much lees offensive when it is working properly. Most of the older piston pumps had well thought-out shear pins and ball-check maintenance options. Make sure the diaphragm pump you select is as well executed. While the diaphragm style pump is correct for your application, don’t forget the peristaltic or hose pump. I have used 4-inch peristaltic pumps for primary sludge (and scum) transfer. These pumps offer low speed/high discharge pressure while using simple rotary motion, unlike a piston or diaphragm unit that employs a crankshaft. Another option would be a recessed impeller pump (Wemco Model “C”), but these are typically designed for a higher flow rate that you may need.
Steve

 

[micalbrch]

The high grit and solids content favors a (piston) diaphragm pump over a piston/plunger pump. There is a difference between a piston and a plunger pump but I suppose yours is a plunger pump because of the 12.25" diameter. What is your flow and pressure? Both are important to know to select the correct pump type. Peristaltic pump, piston disphragm pump, diaphragm pump - they are technically all possible solutions but there is also the financial aspect to consider (purchase price).