What is an expansion valve?
The expansion valve is a piece of device that reduces the system pressure. The most common form of expansion valves is the thermal expansion valve (TMV), which is used in heating systems, ventilation and air conditioning (HVAC). Two main types of air conditioning expansion valves are thermostatic expansion valves and capillary tubes.
Thermostatic expansion valve controls the flow of refrigerant and can work at different temperatures or pressures. The capillary tube is responsible for the transfer of pressure levels in the system to the sensing tube connected to the thermostatic expansion valve and basically acts as a throttle. The air conditioner has three main parts: compressor, capacitor and evaporator. The extension valve is part of the evaporator.
For cooling the building, chilled gas such as freon®, passes through a compressor where it becomes hot and under pressure. The gas then passes through coils that cause heat distraction, which condenses back to the liquid. The condensed liquid then passes through the expansion valve, KDE evaporates and becomes cold gas that pulls heat from the ambient air. The gas passes through another set of coils and the blower blows cold air inside the building and the heat that has been generated during the process is venting out. The refrigerator or freezer works in the same way.
The whole process is performed under pressure, which requires the use of a thermostatic expansion valve. When the pressure inside the compressor reaches the preset level, the thermostatic expansion valve opens, allowing pressure to reduce. Freon® then moves through the valve to the evaporator. This maintains both the flow and the pressure in the air conditioning system.
The capillary tube contains a filter at one end made of a fine net that prevents the thrusts to get in The Tube. It works almost the same as a thermostatic expansion valve, but cannot withstand significant changes in temperature or pressure. The capillary tube is designed for constant tEplot and pressure and acts as a throttle between the capacitor and the evaporator.
The tube is usually long and narrow to allow some Freon® evaporation as it passes through the tube. It is necessary to make freon® entering the evaporator similar to the temperature to the temperature already in the evaporator. Similar temperatures increase the system more efficiently and accelerate the cooling process.