Pressure Reduction and Temperature Drop: The high-temperature and high-pressure liquid refrigerant from the condenser is throttled and decompressed when passing through the narrow valve port of the expansion valve. The pressure drops rapidly to the evaporation pressure, and the temperature also decreases accordingly, forming a low-temperature and low-pressure liquid-gas mixture, which lays the foundation for the refrigerant to absorb heat and evaporate in the evaporator.

Flow Regulation: According to the actual cooling load of the evaporator (i.e., how much heat needs to be absorbed), the expansion valve can automatically adjust the flow of refrigerant entering the evaporator. For example, when the cooling demand increases (such as the temperature inside the freezer rising), the valve port opens larger to increase the refrigerant flow; when the load decreases, the valve port shrinks to reduce the flow, avoiding waste of refrigerant or insufficient cooling.

Prevent Blockage: The most common fault of the expansion valve is blockage, which is mainly divided into "dirt blockage" and "ice blockage". Dirt blockage is usually caused by impurities (such as welding slag, iron filings) in the refrigeration system not being filtered out; ice blockage is due to excessive moisture in the system, which freezes at the valve port when the refrigerant is throttled and cooled. To avoid blockage, it is necessary to ensure that the system is clean during installation and maintenance, and replace the drying filter regularly (the drying filter can absorb moisture and filter impurities).

Avoid Leakage: Check the connection parts of the expansion valve (such as the interface with the refrigerant pipeline) regularly for refrigerant leakage. If oil stains are found (refrigerant will carry lubricating oil when leaking), it is necessary to use a leak detector to confirm the leak point and re-seal or replace the parts in time.

Do Not Disassemble Casually: The internal structure of the expansion valve (such as the valve core, spring, and temperature-sensing element) is precise. Unauthorized disassembly will easily damage the components or affect the control accuracy. If there is a fault, it should be inspected and repaired by professional technicians.

Regular Inspection of Control Performance: For thermostatic expansion valves, check whether the temperature-sensing bulb is tightly attached to the evaporator pipeline (loosening will lead to inaccurate temperature detection); for electronic expansion valves, check whether the connection between the electronic control unit and the valve is normal, and whether the opening degree can be adjusted smoothly.