With the continuous expansion of vacuum technology in various application fields, the demand for direct coupled rotary vane pump is increasing. Some foreign vacuum manufacturers have set up professional factories in China because of the large number of pumps, heavy processing and installation workload and low quotation. The vacuum pump is a rotary variable volume pump, which can only be used in conjunction 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 at the exhaust port of Rongxiang vacuum pump:First, the sealing solvent is too large and the pumping speed of the selected vacuum pump is too small.Second, the vacuum oil is overfilled, resulting in the vacuum pump ejecting with the exhaust port during operation.Vacuum pump continues to develop at a high speed. Due to the high-speed friction between the sliding plate and the pump body, the oil is easy to oxidize and decompose. In particular, the diffusion pump often works in high temperature environment, which increases the steam pressure and reduces the vacuum in the system. Therefore, the vacuum pump oil is required to have good thermal oxidation stability. Domestic small and medium-sized direct coupled vane pumps have passed the technical standards, 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 oil leakage of shaft seal and the functional quality of rotary vane material and vacuum pump oil, ensure the stable and reliable operation of direct connected rotary vane pump at high speed and high temperature, and further improve the ability of domestic direct connected rotary vane pump to remove water vapor.