Refrigeration oil can replace vacuum pump oil
The oil in the vacuum pump is dirty, can you use frozen oil instead? To understand this problem, we must first understand what the two have in common and what are the differences between them. For you to analyze whether refrigeration oil can replace vacuum pump oil.
First of all, the refrigeration oil and vacuum pump oil should not only play the role of lubrication in the cylinder, piston, valve, bearing, sliding plate and other parts, but also play a sealing role in preventing the compressed gas channeling between the piston and the cylinder wall, and have the chemical stability that does not work with the compressed gas.
Vacuum pump oil
Vacuum pump oil is a special lubricating oil for mechanical vacuum pump. Although there are different types of pumps, the requirements for oil quality are the same. When the vacuum pump is running, the oil in the pump cavity plays a sealing role to make the pump obtain the necessary vacuum degree. On the other hand, the oil in the pump cavity is affected by friction, temperature and pressure reduction, and the components with high vapor pressure evaporate into the vacuum space, polluting the vacuum system and limiting the increase of vacuum degree. In addition to suitable viscosity, high viscosity index, good oil-water separation and excellent thermal oxidation stability, the main quality requirements of vacuum pump oil are low saturated vapor pressure and extremely strong limit, so as to ensure high vacuum degree. Therefore, in the production of vacuum pump oil, in addition to selecting the appropriate base oil type, single narrow distillate oil or pure chemicals should be used instead of blending several kinds of distillates as far as possible.
It is more necessary for oil to have excellent low temperature performance and good separation with refrigerant or water. Therefore, deep refining low freezing point naphthenic base oil is generally used in the production of refrigeration oil. It is worth noting that when SO2 is used as refrigeration oil, deeply refined lubricating oil (such as white oil) without aromatics and sulfur oxides should be selected, otherwise, colloidal precipitation will be formed, which will affect the operation of the refrigerator. When chloroethane is used as refrigerant, petroleum will be dissolved, and glycerin and castor oil are generally used for lubrication; when ammonia or carbon dioxide is used as refrigerant, lubricating oil without fat oil should be used, because the fat oil is easy to emulsify, which is not conducive to water separation and then to freezing, and the thermal conductivity of the fatty oil is small, which will reduce the refrigeration efficiency.
Vacuum pump oil has its unique substitution principle：
1. Try to use the same kind of oil or oil products with similar performance and similar additives.
2. Replace the low quality with the high quality oil, that is, select the oil with high quality, so that the lubrication of the equipment can be more reliable and the working efficiency of the equipment can be improved. At the same time, it can also extend the service life, which is economical.
3. The viscosity of the substitute oil should not exceed ± 25% of the original oil viscosity. In general, priority should be given to oil products with higher viscosity.
4. The environment and working temperature of the equipment should also be considered when selecting alternative oil. For the mechanical equipment with large working temperature change, the viscosity temperature property of substitute oil is better; for the machinery working at low temperature, the pour point of substitute oil should be lower than 10 ℃ below the working temperature; for the machinery working at high temperature, the flash point of the substitute oil should be higher, and the oxidation safety should also meet the use requirements.
Vacuum pump manufacturers remind you that the use of refrigeration oil instead of vacuum pump oil is not advisable in most cases, to avoid the deterioration of oil quality caused by mixing and substitution of oil products, resulting in the reduction of equipment efficiency or even damage.