Roots gear pump calculation

In recent years, driven by the traditional industries such as semiconductor manufacturing, liquid crystal injection, solar cell production, new emerging industries such as electronic devices and thin film preparation, chemical industry and pharmacy, Roots gear pump is one of the core equipment and its development and production are more and more Pay attention. Roots gear pump to meet the IC equipment manufacturing industry, high temperature, long-term stable operation, low noise, simple maintenance, clean and oil-free and many other requirements, is a promising development of a dry vacuum pump. However, in addition to the processing and assembly requirements of high precision, difficult processing, one-time expensive investment and other constraints, the design theory and manufacturing processes need to be improved, including the improvement of Roots-type lines, lower processing costs, clearance determination, Leakage calculation, the thermodynamic analysis of the pump, the rotor surface coating, noise and vibration and other difficult issues, restricted the development and production of multistage Roots dry pump. Gap design is one of the most important parameters of multistage Roots dry pump design. In the gear pump operation, the gap by the rotor and pump cavity thermal deformation greater impact. In this paper, the internal heat transfer process of multistage Roots dry pump is analyzed, and the heat transfer model of the working process is established. Through the contact and non-contact temperature measurement methods, the multi-point temperature was measured and the boundary conditions of thermal load were obtained. Based on the ANSYS software, the temperature field of the pump body and the rotor shaft during steady operation is analyzed, and the thermal deformation of the pump shaft and the pump chamber is calculated by thermal structural coupling analysis. The deformation of the rotor shaft and the pump chamber is obtained and the deformation Cloud graph and curve. The thermal deformation data obtained by the above method provide a reference for determining the clearance and provide the basis for further calculation of the leakage of the dry pump during operation. Roots gear pump in a hybrid compression process, the compressed gas heat.With the repetition of the work cycle, the heat generated accumulation, and gradually passed to the rotor and the pump wall, causing the rotor and the pump wall temperature. As the temperature increases, the rotor and pump chamber will have some thermal deformation, will affect the size of the gap passage. Gap is one of the most important parameters in dry pump design. Due to the phenomenon of gas reverse flow, the choice of clearance will seriously affect the ultimate vacuum, compression ratio, volumetric efficiency and thermal jam of dry pump.