A progressive cavity pump is a type of positive displacement pump and is also known as an eccentric screw pump or cavity pump. It transfers fluid by means of the progress, through the pump, of a sequence of small, fixed shape, discrete cavities, as its rotor is turned. Progressive cavity pumps are used in high viscosity applications or if blending the of the pumped fluid is not desired. Progressive cavity pumps are also considered constant flow pumps since at a given speed, the flow rate is relatively constant despite the system pressure. Flow slippage is normal at higher pressures. A relief valve is an essential part of any progressive cavity pump discharge piping system to prevent over pressuring of the pump and piping system
