Types according to number of cylinders Piston pumps belong among the reciprocating pumps. They need a system of suction and dischargevalves, thanks to which the fluid is moved in a required direction. There are various types – some of them have just one cylinder (called simplex-cylinder pump), others may have up to four cylinders (quad-cylinder pump) or even more. Most reciprocating pumps are duplex- or "triplex-cylinder types (with two or three cylinders). Types according to the way of suction and discharge Piston pumps can also differ according to the direction of suction and discharge.Single acting piston pumps have independent suction and discharge strokes, while double acting pumps perform suction and discharge in both directions. Application Piston pumps are usually driven by air or steam, or by a belt drive from an independent engine. Piston pumps were very popular in the times of the industrial revolution in the 19th century, but nowadays they are used less often. Their usual application is for pumping fluids with high resistance, where high flow rate is not needed. Typical pumped materials include for example concrete and heavy oils.