Oil cooler is also called oil cooler, according to the principle of refrigeration system, low temperature and low pressure liquid refrigerant in the evaporator heat exchange with the surrounding water evaporator absorbs the heat of oil, evaporates into low temperature and low pressure gas, the refrigerant temperature remains unchanged during the evaporation process, low temperature and low pressure gas refrigerant enters the compressor, compressed by the compressor, is compressed into high temperature and high pressure gas, and then enters the condenser. Heat exchange is carried out between the condenser and the indoor medium. Part of the heat in the gaseous state of high temperature and high pressure is absorbed by the medium, the temperature of the medium rises, and the heat release of the refrigerant becomes the liquid state of high temperature and high pressure. The process temperature of the condenser remains unchanged, and then the refrigerant enters the expansion valve for throttling. After this process, the refrigerant enters the evaporator for heat exchange and evaporation, so as to achieve the whole process of the refrigeration system. This cycle is continuous, and the oil can be continuously cooled.