Screw pumps belong to the rotary positive displacement group of industrial pumps. They are equipped with one or more screws that rotate inside a cylindrical cavity. The fluid moves linearly with the immersing screws until it reaches the discharge side of the pump. The clearance between the screw and the cavity inside the casing is very tight, hence allowing the fluid to gain pressure as it travels through the pump.
The screw pump is available in a variety of different designs to satisfy the requirements of different applications.
While there are several designs available for screw pumps, all work using the basic principle of two screws counter-rotating each other. Two screws facing opposite directions engage and create a sealed cavity with the pump casing. As fluid enters the pump through the suction side, the drive screws rotate and steadily move the fluid from the inlet to the discharge side. The pump ensures a volumetrically steady flow rate no matter the amount of pressure applied. This kind of operation makes the screw pump a better choice for handling a wide range of liquid types, flow rates, pressures, and viscosities.