What are the operation steps of pressurization, leak detection, vacuumizing, oiling and fluorination of semi-closed compressor in cold storage?

Suppression and leak detection: after connecting the copper pipe, nitrogen gas (refrigerant is ok, but it wastes cost) is added from the low-pressure three-way valve, and it is first increased to 0.5MPA, and the welded joint and the interface with the copper screw are inspected with concentrated cleaner. If there is no big leakage, add nitrogen to 1 ~ 1.2 MPa, and check the copper screw interface. If time permits, after 24 hours, the pressure will not differ by 0.02MPA, which can ensure no leakage. The temperature is higher at noon than in the morning, and the pressure rises better. \x0d\ vacuumizing: it is best to connect from the high-pressure end and evacuate for 20 minutes (if there is slight leakage in the system, too much external wet air will enter if the evacuation time is too long). If you have experience, you can also judge whether there is leakage in the system when vacuuming. \x0d\ Refueling: Close the high-low pressure three-way valve, drain it from the high-pressure three-way valve, connect the low-pressure valve with the oil by pipeline, and pay attention to the highest oil gauge of the oil mirror. \x0d\ Fluorination: Under vacuum, inject liquid from the liquid storage bottle, touch two thirds of the height of the liquid storage bottle with your hand, stop adding liquid when your hand feels cold, add a small amount of gas from the low pressure, start the machine, and then add it to the refrigerant condensation pressure corresponding to the external temperature. Start debugging. If the operating system is in use, it is necessary to adjust the opening of the expansion valve according to the current storage tank temperature and the cooling condition of the compressor, and fill it slowly and properly.