A brief discussion on the working mechanism of dryers

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The amount of water vapor in compressed air is determined by its temperature: while keeping the pressure of the compressed air relatively constant, lowering its temperature reduces the water vapor content, and the excess water vapor condenses into a liquid. A cold dryer utilizes this principle, employing refrigeration technology to dry compressed air. Therefore, the cold dryer has a refrigeration system. The refrigeration system of a cold dryer belongs to the compression-type refrigeration system, and it consists of four basic components: a refrigeration compressor, a condenser, an evaporator, and an expansion valve. They are connected to each other in sequence through pipes, forming a closed system. The refrigerant circulates continuously within this system, undergoing state changes while exchanging heat with compressed air and cooling media. The refrigeration compressor draws in the low-pressure (low-temperature) refrigerant from the evaporator into the compressor cylinder; the refrigerant vapor is compressed, resulting in an increase in both pressure and temperature ； The high-pressure, high-temperature refrigerant vapor is sent to the condenser, where it exchanges heat with cooler water or air. The heat from the refrigerant is absorbed by the water or air, causing the refrigerant to condense and turn into a liquid. This liquid is then sent to the expansion valve, where it is throttled to become a low-temperature, low-pressure liquid before entering the evaporator ； Inside the evaporator, the refrigerant liquid at low temperature and low pressure absorbs heat from the compressed air and vaporizes (commonly known as \"evaporation\"); meanwhile, the compressed air is cooled, causing a large amount of liquid water to condense ； The refrigerant vapor in the evaporator is then drawn in by the compressor, allowing the refrigerant to go through four processes—compression, condensation, throttling, and evaporation—in the system, thus completing one cycle.