In the vacuum pump vacuum pump oil not only as a vacuum medium, the mechanical friction point of lubrication, cooling and sealing.
The main performance requirements:
1. extremely low vapor pressure
This is the most important performance of vacuum pump oil, because the vacuum pump requires a high degree of vacuum, usually using a paraffin based narrow fraction of the oil, for the diffusion vacuum pump, and the use of low vapor pressure of silicon oil or other synthetic oil.
2. suitable viscosity and good viscosity temperature characteristics
The volume of the vacuum chamber is constantly changing to form an exhaust effect, which requires that the lubricating oil should have the appropriate viscosity and viscosity temperature characteristics.
3. good thermal oxidation stability
The vacuum pump is constantly developing to high speed. Because of the high speed friction between the slide and the pump body, the oil temperature rises and the oil is easily oxidized and decomposed. Especially, the diffusion pump often works in a high temperature environment, which makes the steam pressure in the system rising and the vacuum degree lower. Therefore, the vacuum pump oil has a good thermal oxidation stability.
4. good corrosion resistance and emulsifying resistance
If the vacuum pump is a corrosive gas, it will react with the oil and corrode the parts in the pump. The inhaled air often contains water vapor condensate, which causes the emulsification of the vacuum pump oil and the corrosion of the metal, so it is required to have good corrosion resistance and emulsification.
5. higher flash point
The main requirement is not to carry light components in the vacuum pump, so as not to affect the saturated vapor pressure of the oil.
6. lower limit pressure
Limit pressure is an important performance index of vacuum pump oil to understand the limit pressure of vacuum pump under the minimum vacuum limit pressure.