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What Do You Know about Screw Pumps?

Learn - Feb. 23, 2021

A screw pump is a volumetric rotor pump, which relies on the volume change of the seal cavity formed by the screw and bushing to suck in and discharge liquid. The screw pump is divided into single screw pump, double, three and five screw pumps according to the number of screws. The characteristics of the screw pump are smooth flow, small pressure pulsation, self-priming ability, low noise, high efficiency, long life, reliable work; and its outstanding advantage is not to form eddy currents when conveying media, insensitive to the viscosity of the medium, can convey high viscosity media.

Classification of the screw pump

Screw pumps are classified according to the number of screws

1. Single screw pump - a single screw in the pump body of the internal thread groove engaged in the rotation of the pump.

2. Twin-screw pump - by two screws meshed with each other to transport the liquid pump.

3. Three screw pump - pumps with multiple screws meshing with each other to transport liquids.

 Three Screw Pump

Working principle of the screw pump

1. Screw pump is the use of screw rotation to suck and discharge the liquid.

The middle screw is the active screw, driven by the prime mover rotary, the two sides of the screw for the driven screw, with the active screw for the reverse rotation. The threads of the active screw and the driven screw are double-headed threads.

Due to the mutual engagement of the screws and the close cooperation between the screws and the inner wall of the liner, the inlet and outlet of the pump will be separated into one or more sealing spaces. With the rotation and engagement of the screw, these sealing spaces are continuously formed at the suction end of the pump, the liquid in the suction chamber is sealed into it, and the suction chamber is continuously pushed along the screw axially to the discharge end, and the liquid enclosed in each space is continuously discharged, as if a nut is continuously pushed forward when the thread is rotated, which is the basic working principle of the screw pump.

2. Characteristics of the screw pump

Screw pump work, the liquid is sucked into the thread and the pump casing surrounded by the sealing space, when the active screw rotation, screw pump sealing volume in the screw teeth under the squeeze to raise the screw pump pressure, and move along the axial direction. Because the screw is rotating at equal speed, so the liquid outflow flow is also uniform.

Screw pump features are: screw pump losses are small, good economic performance. High and uniform pressure, uniform flow rate, high speed, and can be directly connected to the prime mover.

Screw pump can transport lubricating oil, transport fuel, transport all kinds of oil and polymer, for transporting viscous liquids.

Media containing particles or fibres: particle diameter can be this 30mm (not more than the rotor eccentric distance). Fiber length can be 350mm (equivalent to 0.4 bit rotor pitch). Its content can generally reach 40% of the media cellar, if the solids in the media for the fine powder froth, the highest content can reach 60% or higher can also be transported. Requirements for stable conveying pressure, the medium's inherent structure is not damaged, the choice of single screw pump conveying the most ideal.

The information is provided by the screw pump supplier.