How does a screw pump work?

Screw pump, as a positive displacement pump widely used in many industrial fields, occupies an important position in fluid transportation due to its unique working principle and excellent performance characteristics. This article will explore the working principle of screw pump in depth, from the internal structure to the fluid transportation process, to give you a comprehensive analysis of this efficient and reliable fluid transportation equipment.

Basic structure of screw pump
The screw pump is mainly composed of pump body, screw, bushing, bearing, sealing device and transmission device. Among them, the pump body is the main structure of the screw pump, and the internal design has a spiral chamber matching the screw. The screw is the key working part of the pump, usually composed of one or more intermeshing spiral metal rods, which can rotate in the pump body and roll along the inner surface of the bushing. The bushing is used to support the screw and reduce its wear, and is usually made of wear-resistant material.

Overview of working principle
The working principle of the screw pump is based on the relative movement between the screw and the bushing and the resulting changes in the sealing chamber. When the motor drives the pump shaft to rotate, the screw begins to rotate around its own axis and rolls along the inner surface of the bushing. This movement process forms a series of continuous, closed spiral chambers between the screw and the bushing. As the screw rotates continuously, these chambers gradually move along the axial direction of the pump body, advancing from the inlet end to the outlet end of the pump body.

Fluid delivery process
During the fluid delivery process, the liquid to be delivered first enters the first chamber between the screw and the bushing through the inlet of the pump body. As the screw rotates and moves, this chamber gradually shrinks, compressing the liquid and pushing it to the next chamber. At the same time, the subsequent chambers open in turn and receive the liquid from the previous chamber. This process is repeated until the liquid is continuously delivered to the outlet end of the pump body and discharged from the pump.

Working characteristics of screw pumps
Stable and reliable: The screw pump works on the positive displacement principle, the flow rate is proportional to the speed, and the flow rate fluctuates little and has good stability. At the same time, its structure is simple and compact, with few parts and a low failure rate, so it has high reliability.
Strong self-priming ability: The screw pump can quickly form a vacuum and suck in liquid when it starts, and can achieve self-priming without additional auxiliary equipment. This feature gives the screw pump a clear advantage in situations where self-priming is required.
Strong adaptability: The screw pump can transport liquids of various viscosity ranges, including high viscosity, high solid content fluids and corrosive media. Its unique spiral chamber design reduces the shear force on the fluid during transportation, thereby protecting the physical and chemical properties of the fluid.
Low noise and small vibration: The noise and vibration generated by the screw pump during operation are relatively small, thanks to its stable flow output and reasonable structural design.
Easy maintenance: The parts of the screw pump are easy to disassemble and replace, and the maintenance workload is relatively small. At the same time, its sealing device is reasonably designed and has reliable sealing performance, reducing the risk of leakage.