Requirements for the use of freezing oil

Requirements for the use of freezing oil Due to the different use occasions and refrigerants, the choice of refrigeration oil for refrigeration equipment is also different. The requirements for freezing oil< are as follows: 1. Freezing point: The temperature at which the freezing oil is cooled to stop flowing under the experimental conditions is called the freezing point. The freezing point of the refrigeration oil used in refrigeration equipment should be as low as possible (such as R22 compressors, the refrigeration oil should be below -55 ℃), otherwise it will affect the flow of refrigerant and increase the flow resistance, resulting in poor heat transfer. 2. Viscosity: An important parameter in the characteristics of the viscosity of the frozen oil. The use of different refrigerants requires corresponding selection of different frozen oils. If the viscosity of the refrigerating oil is too large, it will increase the mechanical friction power, friction heat and starting torque. On the contrary, if the viscosity is too low, the required oil film cannot be formed between the moving parts, so that the proper lubrication and cooling effects cannot be achieved. 3. Cloud point: The cloud point of frozen oil refers to the temperature at which paraffin wax starts to precipitate out of the frozen oil when the temperature drops to a certain value, making the lubricating oil cloudy. The cloud point of the refrigeration oil used in refrigeration equipment should be lower than the evaporation temperature of the refrigerant, otherwise it will cause the throttle valve to block or affect the heat transfer performance. 4. Flash point: The flash point of the refrigeration oil refers to the lowest temperature at which the lubricating oil is heated to the point when its steam comes into contact with the flame. The flash point of the refrigerating oil used in the refrigeration equipment must be higher than the exhaust temperature by 15 to 30 degrees Celsius, so as not to cause combustion and coking of the lubricating oil.