Complaint
Refrigerating machine refers to the compressor used in compression refrigeration, because of its use conditions and compression working medium is different, it is different from the general air compressor. According to the working characteristics of the refrigerator and the specific requirements of the lubricating oil, the commonly used refrigerants are: freon, ammonia, lithium bromide, chloromethane, etc.
component
The refrigerant oil should have a good low pour point, a good compatibility with the refrigerant and thermal and oxidation stability. The largest consumption is mineral oil type, generally using naphthenic base oil, it has a low pour point, no wax, low temperature fluidity
Some types of refrigerant oil require synthetic hydrocarbon oil as the base oil
Main function
(1) Lubricate the friction surface so that the friction surface is completely separated by the oil film, thus reducing the friction work, friction heat and wear
(2) The flow of refrigerant oil takes away the friction heat, so that the temperature of the friction parts is kept within the allowed range
(3) Fill the sealing part with oil to ensure the sealing performance and prevent the leakage of refrigerant
(4) The movement of oil takes away the grinding debris generated by metal friction, and plays the role of cleaning the friction surface
(5) Provide hydraulic power for unloading mechanism
classification
In ISO 6743/3B classification, refrigerating oil is divided into DRA, DRB, DRC and DRD according to its composition characteristics, the operating temperature of evaporator and the type of refrigerant used.
The GB/T 16630 frozen oil promulgated in 1996 is divided into two categories: L-DRA, L-DRB/B [1]
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Thermal stability
Thermal stability is generally measured by the flash point of refrigerant oil. Flash point is the temperature at which the steam of refrigerant oil meets fire. The flash point of the refrigerant oil must be higher than the exhaust temperature of the compressor. For example, the flash point of the refrigerant oil used in the R717, R12, and R22 compressors must be higher than 160 ° C.
liquidity
The refrigerant oil should have good liquidity at low temperature. In the evaporator, due to the low temperature, the viscosity of the oil increases and the liquidity becomes worse. When the refrigerant oil stops flowing at a certain temperature, the temperature at this time is called the freezing point of the oil. The freezing point of refrigerating engine oil is required to be low, especially the freezing point requirement of low temperature refrigerating machine is very important. Otherwise, the fluidity is reduced, which affects both the heat transfer of the evaporator and the lubrication of the machine.
The freezing point of all kinds of freezing oil is below -40ºC, which can meet the needs of general purpose refrigerating machine. When the evaporation temperature is low again, precision instrument oil can be used, and its freezing point is generally not higher than -60ºC.
solubility
Various refrigerants are different from freezing oil, which can be roughly divided into three categories:
Those that are insoluble to each other, those that are infinitely soluble to each other, and those that are in between
Turbidity point
The temperature when the frozen oil begins to precipitate the paraffin wax (the oil becomes cloudy) is called the turbidity point. When there is refrigerant, the turbidity point of the frozen oil will drop.
In addition, fully enclosed and semi-enclosed refrigerating machines have certain requirements for the breakdown voltage of refrigerating oil, which is generally above 25kV.
Frequently asked questions
Student: Q1. What's your minimum? A command?
A: Our minutes. The order is an OEM order for 2000 pieces.
Q2. What are your packing conditions?
A: Generally speaking, we pack our goods in neutral white boxes and brown cartons.
Q3. What are your payment terms?
A: T/T 30% as deposit and 70% balance as copy of bill of lading. Telegraphic transfer 30%, letter of credit 70%.
