What Are the Functions of an Expansion Valve?


Most refrigerators and air conditioning systems are made up of condensers, compressors and expansion devices, as stated on the Encyclopedia Britannica website. Expansion valves are used to reduce pressure levels within a given system and ensure it continues to function efficiently. Valves used in heating systems, ventilators and air conditioning units are known as thermal expansion valves. These types of expansion valves work as part of the evaporating system and assist with regulating the extraction and omission of cold and hot air.

Refrigerant Regulation

  • Thermal expansion valves regulate the flow of cooling substances (refrigerant) within a device and work under variable pressures and temperatures. Thermal expansion valves are usually employed to sustain the flow of liquid in air conditioning units. A cooling substance is sent via the compressor to reduce the temperature of a building. The heat of the liquid then gradually increases until it changes into gas.

Gas Transformation and Regulation

  • Once converted, the gas flows down the coil, which results in the heat dissipating and changing back into liquid form. This liquid is then sent to the expansion valve where it transforms into a chilled gas capable of extracting heat from the atmosphere around it. The gas is channeled through a set of tubes, and cold air is pumped into the building premises.

Pressure Regulation

  • Pressure levels are transmitted via the capillary tube toward the sensing tube, which is linked to the thermostatic valve. Thermostatic expansion valves regulate the pressure levels of the whole process to transform the cooling substance into cool, breathable air. If pressure levels grow too high, the expansion valve widens, reducing the pressure within the device. The cooling liquid can then flow smoothly from the expansion valve into the evaporating system.

    Some refrigerators and air conditioning units use capillary tubes in place of expansion valves. Capillary tubes operate in a similar mode to thermal valves but are only tailored to endure a consistent climate. Capillary tubes are unable to handle substantial shifts of pressure levels or temperature.

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