Depending on the nature of the connection of the working chamber with the inlet and outlet of the pump, the pumps differ in periodic (volumetric) and constant (dynamic). Volumetric pumps are applied to pump fluid from one place to another.In these pumps, an energy conversion is used. The energy of the engine is converted into the energy of a head fluid. These are high pressure pumps, they are very sensitive to liquid pollution. The working process in volumetric pumps is not stable, so it is necessary to build an array foundation for them. Their advantages are that they can work with dry suction.