Application features and selection methods of Screw pump
1. Introduction
The screw pump is a positive displacement pump with a rotating screw as its working element. It has a large output and is suitable for a variety of media. Its working energy is mainly provided by the friction between the screw and the casing, so it is also known as an isobaric pump. Its many parameters and working conditions need to be considered in its selection. Screw pumps are widely used in various fields and industries such as industrial, agricultural and urban drainage, petroleum, chemical and nuclear industries.
2. Working Principle
The screw pump is made up of two or more relatively meshing screws that rotate in the same direction. The screws are guided by the special casing, which restricts the screws from moving in any direction other than the desired direction. The medium is forced out of the inlet into the front part of the chamber and pushed forward along its pitch line as the screws rotate. The medium then enters successive smaller chambers and gradually reaches the outlet chamber due to the gradually shrinking space. It is worth noting that each pitch line of the screw is divided into two parts, the pressure side and the suction side, between which a certain working pressure is maintained.
3. The Characteristics of the Screw Pump
1) The output flow is very stable, with the speed of the motor remaining constant, so that the output flow of the pump remains steady, which is not affected by the pressure fluctuation of the medium in the pipeline.
2) The pump performance is not sensitive to the fluid in the pipeline and can pass suspended matter and gases.
3)The screw pump is sealed by static and dynamic seals, so it has the characteristics of hermetic and stable performance.
4)Small vibration, low noise.
5)Low working temperature and small starting torque.
6)Simple structure, small volume and light weight.
7)High volumetric efficiency, high self-priming ability, no negative pressure at the inlet, and can suck in the medium from the lower part.
4. Practical selection of screw pump
1) Select according to the required flow rate: When selecting the screw pump, first determine the required flow rate, that is, the flow rate at which the screw pump needs to work in the application. This flow rate is usually determined by the size of the process device or system to be applied.
2) Select according to required pressure: according to the relevant parameters of the process device or system, determine the required pressure and select the screw pump with the corresponding working pressure.
3) Select according to system pressure: The pressure of the system, as well as the characteristics of the system and the medium flow, should also be considered when selecting a screw pump. In order to ensure the normal operation of the screw pump, the eddy current losses of the system should be reduced to a certain extent, and it is necessary to ensure that the operating pressure of the system is within the normal range of the pump and is suitable for the running characteristics of the pump.
5. Conclusion
The screw pump is a positive displacement pump with a rotating screw as its working element. It has a larger output and can be used for various media. In order to ensure the normal operation of the screw pump, the relevant parameters and working conditions must be considered in its selection. This paper introduces the working principle, characteristics and selection of screw pump.
It is hoped that this introduction can provide a reference for selection and application of screw pumps and help us better understand the use of screw pumps.
