With the continuous expansion of vacuum technology in various application fields, the demand for direct connected rotary vane pump is increasing. Some foreign vacuum manufacturers have set up professional factories in China because of the large number of pumps, heavy workload of processing and installation, and low quotation. The vacuum pump is a rotary variable volume pump, which can only be used with the previous pump. It has a large pumping speed in a wide pressure range. However, generally speaking, there are two reasons for fuel injection in the exhaust hole of Rongxiang vacuum pump One is that the sealing solvent is too large, and the vacuum pump is too small. The second is the excessive vacuum refueling, which causes the vacuum pump to eject with the exhaust port in the process of operation. Vacuum pump is developing rapidly. Due to the high-speed friction between the vane and the pump body, the oil is easy to be oxidized and decomposed. Especially the diffusion pump often works in high temperature environment, which increases the steam pressure and reduces the vacuum degree in the system. Therefore, the vacuum pump oil is required to have good thermal oxidation stability. Domestic small and medium-sized direct rotary vane pump has passed the technical standard, and the price is far lower than that of foreign pumps, so domestic pumps still have competitive advantages. The key is to deal with the leakage of shaft seal, the function and quality of rotary vane material and vacuum pump oil, ensure the stable and reliable operation of direct connected rotary vane pump under high speed and high temperature, and further improve the water vapor removal ability of domestic direct connected rotary vane pump.