Vacuum pump oil selection

Vacuum pump oil selection requirements

1. Vacuum pump oil tightness

Vacuum pump oil needs suitable 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. vacuum pump oil of saturated vapor pressure

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

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

3. vacuum pump oil of limit total pressure and limit partial pressure

Limit total pressure: The total pressure produced by all substances (gases) in a vacuum pump is measured by a Pirani gauge or a thermocouple vacuum gauge. At present, foreign countries pay attention to the test indexes of full pressure.

Limit partial pressure: Limit partial pressure of the pump measured by mercury compact vacuum gauge (Maxwell gauge) should be less than 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.

HFV-A Series High Vacuum Pump Oil

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4. vacuum pump oil of the smoothness

Frictional wear, fatigue wear and corrosive wear are all related to smooth conditions. Excellent performance of vacuum pump oil is conducive to inhibition of corrosion wear; can effectively reduce adhesive wear and external wear; fluid smoothing agent on the friction surface cleaning role, but also to reduce friction wear. Reduce friction resistance to save energy and reduce wear to extend mechanical life.

5. vacuum pump oil cooling performance

Reducing the temperature of the friction surface is an important function of smoothness. When the friction surface moves, work must be done by restraining the friction force. All the work consumed by restraining the friction force is converted into heat, which will cause the temperature of the friction surface to rise. The magnitude of friction heat is related to the smooth state. The heat of high viscosity is the largest, the heat of low viscosity is the smallest, and the heat of boundary friction is between the two. Therefore, the vacuum pump oil with suitable viscosity can not only smooth the liquid, reduce the generation of friction heat, but also can bring the friction heat out of the pump in time.

6. vacuum pump oil of the cleanliness

The friction pair must be prevented from contacting with the surrounding medium, causing corrosion and rusting. Excellent vacuum pump oils require cleaning of the friction area as much as possible; corrosion resistance and rust prevention and maintenance of the friction surface from oil degeneration or external corrosion.