RECIPROCATING PUMPS FOR VISCOUS MATERIALS.

Pumping very viscous or semi-solid materials, which do not seek a uniform surface level, requires techniques which differ from most conventional pumps. The air-driven reciprocating piston pump is commonly used for this service. Piston pumps, driven by reciprocating hydraulic cylinders, are also used to pump viscous materials. A principal advantage of these pumps is their ability to operate over a wide range of speeds and pressures. The piston of the drive motor may be the same size as the pump piston, or it can be much larger. Generally, in an air-over-hydraulic system, the driving piston has a much larger area than the pump piston. If the effective area of the air-motor piston is 10 times the effective area of the pump piston, the pump has a 10:1 pressure ratio.