These pumps have a diaphragm, piston or plunger which is reciprocating back and forth through a fixed stoke length. The diaphragm pumps use a circular semi-flat membrane that is flexed from a concave to a convex shape within a sealed chamber. There is no actual sliding contact of parts in the pumping chamber and therefore these pumps can handle solids, slurries, fibrous and very thick liquids quit well. Most diaphragm pumps are air operated, but electric do exist. Electric models are typically very small with several individual diaphragms working in series being driven by a rotating angled cam or a single diaphragm being driven by a mechanical connection to a solenoid. In this case, they are typically designed as metering pumps. Piston pumps like the name implies have a piston, ceramic typically, reciprocating within a very tight tolerance cylinder. Because of their materials of construction and mechanical design, they produce extremely high discharge pressures. By making them with several pistons working together in a single head a semi-steady flow can be obtained. With any of these pumps special consideration must be given to the cyclic pressure or hydraulic pulsation’s which naturally occur. Typical Positive Displacement Reciprocating pumps include AODD, single diaphragm, electric diaphragm, metering or proportioning and piston to name a few.
Categories within Reciprocating Pumps - Diaphragm, Piston, Plunger