vacuum pump oil performance

Vacuum pump oil is a lubricating oil specially developed for vacuum pump of vacuum equipment, which is divided into mineral oil and synthetic oil. It can prevent the oil from backflow and diffusion from the inner cavity of the pump to the vacuum system, so as to ensure sufficient limit vacuum. It can quickly separate the water entrained in the oil and reach the required vacuum degree.

vacuum pump oil main properties

1. Sealing performance of vacuum pump oil

The vacuum pump oil needs proper viscosity, low temperature can make the vacuum pump start quickly, the vacuum pump oil can have good sealing performance at high temperature, and the temperature rise of vacuum pump oil in pump vacuum pump is low. It does not contain light volatilization components, which can reduce the oil return rate of vacuum pump.

2. Saturated vapor pressure of vacuum pump oil

One of the key indexes of saturated steam pressure is vacuum pump oil. In a closed vessel, the saturated vapor liquid reaches dynamic equilibrium at constant temperature and vapor pressure.

The saturated vapor pressure oil should be as low as possible. The maximum working temperature of the pump should still have enough low saturated vapor pressure, which is lower than the limit pressure of vacuum pump. A temperature of at least 6.5 x kPa at 60 ° C (saturated vapor pressure is about to drop by an order of magnitude due to an increase in temperature of 20 ° C).

3. Vacuum pump oil, limiting total pressure and limiting partial pressure

Limit total pressure: Pirani vacuum gauge and thermocouple vacuum gauge measure the total pressure of vacuum pump (gas) of all materials. At present, the test emphasizes the total pressure index.

Limit partial pressure: Mercury compression vacuum gauge (MacLeod manometer) limits air measurement pump pressure, double rotating vane pump pressure should be less than 6 * 10-5kpa. The difference between the total pressure and the ultimate pressure is not more than an order of magnitude. The greater the difference between the two, the more volatile components the vacuum pump oil contains, and the lower the properties of the oil.

(Note: limit pressure and limit pressure double stage high vacuum pump test)

4. Lubricity of vacuum pump oil

Friction and wear, surface fatigue wear and corrosion wear and so on. The good performance of vacuum pump oil is beneficial to inhibit corrosion and wear, which can effectively reduce surface adhesion wear and fatigue wear; the cleaning effect of liquid lubricant friction surface can also reduce friction and wear. It can save energy, reduce friction resistance, reduce wear and prolong the service life of machinery.

5. Cooling performance of vacuum pump oil

Reducing the temperature of the friction surface is an important lubrication. Friction surface movement must overcome friction and work, power consumption in overcoming all work of friction heat, the result will lead to friction surface temperature rise. The size of the friction heat depends on the state of lubrication, the maximum high viscosity, the lower viscosity, and the lowest thermal boundary between the two. It can be seen that the appropriate viscosity of vacuum pump oil can not only realize liquid lubrication and reduce the generation of friction heat, but also can timely rub the heat pump outside the body.

6. Detergency of vacuum pump oil

Friction pairs are inevitably exposed to the surrounding media, which can lead to corrosion and corrosion. The vacuum pump oil with excellent performance needs to eliminate friction area as much as possible, clean and clean; corrosion, rust prevention and friction surface protection are not affected by oil deterioration or external erosion.

7. Oxidation stability of vacuum pump oil

The oxidation stability shows the anti-aging performance of lubricating oil, which is a special performance requirement of vacuum pump oil industrial line operation. All lubricants are based on their chemical composition and different external environmental conditions, and have varying degrees of automatic oxidation tendency. When the vacuum pump oil is oxidized by air (or oxygen) and metal catalyst at a certain temperature for a certain time, the acid value, viscosity and precipitation of the oil will change. The oxidation process is used to gradually generate some aldehydes, ketones, acids and resins, asphaltenes and other substances. The oxidation stability is the material that inhibits the performance of the product.

8. Thermal stability of vacuum pump oil

The expression of high temperature resistant oil, that is, is resistant to high temperature decomposition of oil, that is, thermal decomposition temperature. It is proposed that severe vacuum environment will be used for thermal stability requirements.

Natural mineral oil has its inevitable defects. Compared with synthetic oil, the composition and thermal oxidation decomposition of pump oil are easy to deteriorate, the extreme pressure stability is poor, and the pumping speed also reduces the use time. Generally, the D943 oxidation test method for pure mineral oil takes about several hundred hours, while the D943 for synthetic oil can be extended to more than 3000 hours. It can be seen that its service life is prolonged.

9. Emulsion resistance of vacuum pump oil

During the operation of the vacuum pump, the pump and the oil are discharged from the water and air conditioning system. If the emulsification of the vacuum pump oil is not good, it will form a mixture of emulsion and water, and the bottom of the circulating water tank which is not easy to release, which may lead to the reduction of the vacuum degree and the poor lubrication.

Demulsibility is a very important physical and chemical property of industrial lubricants. Especially in the process of vacuum drying for medical, food, ceramics and other industries, the anti emulsifying performance of pump oil is more important. Demulsification good oil-water separation ability of pump oil, water vapor condensate gas through opening the valve, will discharge part of the water vapor. In addition, the low viscosity oil of the pump is higher than the high viscosity oil.

10. Anti foaming property of vacuum pump oil

During the operation of the vacuum pump, because of the existence of air, foam often occurs, especially oil containing surface active additives. It is more likely to generate foam, and foam is not easy to disappear. The use of lubricating oil to produce foam will damage the oil film, not only make the friction surface sintered or increase wear, but also promote the oxidation of lubricating oil. The operation of the vacuum system, the exhaust gas from the oil sealed by the vacuum pump will be continuously discharged, a lot of foam oil surface, and the oil pollution and equipment caused by the overflow of the vent hole pump. Adding anti foam agent to pump oil, anti foam effect is significantly improved.