The refrigerating dryer uses the low temperature of the evaporator of the refrigerating system,let's lower the temperature of the compressed air,and then condense the water out,to obtain a dry compressed air source;but cooling the compressed air doesn't necessarily mean the water will be expelled,because a lot of condensed water will be taken away from the refrigerated dryer due to the rapid flow of compressed air, resulting in the phenomenon of excessive water content at the service end;