The main functions of the throttle mechanism are: throttling and reducing the pressure of the high-pressure refrigerant flowing out of the condenser; adjusting the flow rate: when the refrigeration load increases, the refrigerant flow rate will increase, and when the refrigeration load decreases, the refrigerant flow rate will decrease. According to this principle, the throttle valve can control the refrigerant flow rate by adjusting the heat load of the refrigerant. Control superheat: the throttle of the throttle can control the superheat of the refrigerant, at the same time, it can also control the entry and exit of the refrigerant, and can prevent liquid from flowing into the compressor and cause damage to the compressor.