What are Waste Water Grinder Pumps
"Grinder" pumps are used both in residential and small industrial/commercial system. Waste water pumps are basically a "centrifugal" pump except that in the waste water systems, the impeller is more of an "open" impeller. This allows the impeller to handle larger "solids" than a "closed" impeller in a fresh water centrifugal pump and helps to minimize clogging. In addition, the waste water pump will have a larger inlet and outlet for the same reason... size of solids being passed.
Well, that's where the "Grinder" pump comes into the picture. A grinder pump is a type of "Submersible" pump as you can see from the left photo above. This type of pump has a set of "grinding" (or cutting) blades (one type shown in the right hand photo above), that are designed to "cut up" the solids that are sucked into the inlet of the pump, like a toothbrush, or a Lego toy, or a wash cloth, etc. These cutters are attached to the extreme end of the shaft, so that any solid gets to them before it gets to the impeller and causes a clog. In some cases, a standard waste water pump with an open impeller and a large enough inlet and outlet may very well "pass through" these smaller items. But something like a towel, may not be so easy.
Grinder pumps may very well do the job, if the debris isn't too difficult to cut up. But things like clothing, canvas, metals, glass, etc., those won't work well with this pump. Keep in mind too, that the "cutter blades" do get dull if they are asked to cut up material on a continuous basis. That means a maintenance expense AND downtime. If you can't afford downtime of the waste stream, you need to have a spare pump sitting around.
So Grinder pumps have a place in some waste water systems, but not all. Give the folks at A.R.&E. a call to discuss your application and we'll do our best to help you make the right decision.