The Definitive Guide to Pressure Washer Pumps (Updated ...
13/08/2015 · Pressure Washing Pump Types. The are two general groups of positive displacement pumps: Reciproing – Uses pistons, plungers or diaphragms. Rotary – Uses screws, gears, vanes or lobes. All pressure washer pumps are in the reciproing group and use pistons or plungers to add energy to the water.