How to choose the right vacuum pump oil?

The quality of vacuum pump oil depends on the viscosity and vacuum degree, and the vacuum degree depends on the value at different temperatures. The higher the temperature is, the more stable the vacuum degree is.Let’s learn more about the following：
I.Recommended oil viscosity range of vacuum pump:
i. The piston vacuum pump (W type) use general engine oil, with V100 and V150 viscosity grade oil.
ii. The rotary vane vacuum pump (2x type) use v68 and V100 viscosity grade oil.

iii.The direct-connected (high-speed) rotary vane vacuum pump (2XZ type) uses V46 and V68 viscosity grade oil.
iv. The slide valve vacuum pump (H type) use v68 and V100 viscosity grade oil.
v. V32 and v46 vacuum pump oil can be used for lubrication of Roots vacuum pump (mechanical booster pump) gear transmission system.

II.The principle of viscosity selection
The selection of oil viscosity is one of the important factors for the performance of vacuum pump.The viscosity of a liquid is the resistance of the liquid to flow, or the internal friction of the liquid.The greater the viscosity, the greater the resistance of the moving speed of various components, the higher the temperature rise and the greater the power loss;If the viscosity is too small, the sealing performance of the pump becomes poor, resulting in gas leakage and poor vacuum.Therefore, various vacuum pumps are very important for the selection of oil viscosity. The principles for the selection of oil viscosity are as follows:
i. The higher the speed of the pump, the lower the viscosity of the selected oil.
ii. The greater the linear speed of the pump rotor movement, the lower the viscosity of the selected oil.
iii. The more precise the machining accuracy of pump components or the smaller the clearance between friction parts, the lower the viscosity of the selected oil.
iv. When the vacuum pump is used under high temperature conditions, it is appropriate to select the oil with high viscosity.
v. For the vacuum pump with cooling water circulation, the oil with low viscosity shall be generally selected.
Vi.For other types of vacuum pumps, the corresponding oil products can be selected according to their rotating speed, processing accuracy, extreme vacuum, etc.

If the vacuum pump is not frequently replaced and maintained manually during long-term use, the vacuum pump oil will be emulsified or carbonized, resulting in a series of problems such as wear of the vacuum pump cylinder, blockage of oil pipes and oil filters.If the oil mist separator is blocked, the gas pumped into the pump body will not be easily discharged. At this time, the internal pressure in the pump body is too high, and the pumping speed is reduced, resulting in the decrease of vacuum degree.Therefore, replace the vacuum pump oil in time.