Answer: The dew point temperature refers to the temperature when the air is cooled to saturation under the condition that the water vapor content and air pressure do not change. Figuratively speaking, the temperature when the water vapor in the air turns into dew is called the dew point temperature.
The range of the dew point temperature of the cold dryer is limited by three conditions, namely: ①The limit of the freezing point bottom line of the evaporator temperature; ②The limit that the heat exchange area of the evaporator cannot be increased infinitely; ③The limit that the separation efficiency of the "gas-water separator" cannot reach 100%.
JB/JQ 209010-1988 "Technical Conditions for Compressed Air Refrigerated Dryers" stipulates that the "pressure dew point" of the cold dryer is . Most domestic manufacturers give a range limit to the "pressure dew point" of the cold dryer (for example:). According to its lower limit, there will be no icing inside the cold dryer even under the lowest load condition; and the upper limit stipulates the water content index that the cold dryer should reach under rated conditions. Under good working conditions, it should be possible to obtain compressed air with a "pressure dew point" of about ! through the refrigerated dryer.