Performance of vacuum pump oil

1. Tightness of vacuum pump oil:

Vacuum pump oil needs to have appropriate viscosity, can make the vacuum pump start quickly at low temperature, vacuum pump oil can have good sealing at high temperature, vacuum pump oil has a low temperature rise in the pump. It does not contain light volatile components and reduces the oil return rate of vacuum pumps during operation.

2. Saturated vapor pressure of vacuum pump oil:

Saturated vapor pressure is one of the key indicators of vacuum pump oil. In a constant temperature closed container, when vapor liquid two phase is in dynamic equilibrium, the pressure term is saturated vapor pressure.

The saturated vapor pressure of oil products should be as low as possible. At the highest working temperature of the pump, the saturated vapor pressure should be sufficiently low and should be lower than the limit pressure stipulated by the vacuum pump. The saturated vapor pressure will drop by about an order of magnitude for every 20 C rise in temperature, at least 6.5 10 - 5 kPa at 60 C.

3. Limit total pressure and limit pressure of vacuum pump oil:

Limit total pressure: The total pressure produced by all substances (gases) in the vacuum pump is measured by a Pirani gauge or a thermocouple vacuum gauge. Foreign countries now attach importance to the test target of full pressure.

Limit Partial Pressure: Limit partial air pressure of the pump measured by mercury compression vacuum gauge (Maxwell gauge) and the partial pressure of the two-stage rotary vane pump should be <6 *10-5 kPa. The difference between limit total pressure and limit differential pressure is not greater than one order of magnitude. The greater the difference between the two, the more volatile components in vacuum pump oil, the worse the nature of the oil. (Note: limit total pressure and limit partial pressure are tested by two stage high grade vacuum pump).