| 摘要 |
A method and apparatus are provided for continuously drying and chilling a high temperature, pressurized gas such as air to sub-zero temperatures. The high temperature pressurized gas is passed alternately through each of two parallel heat exchangers containing cooling coils through which cold refrigerant from a refrigeration system is passed. While one of the heat exchangers is being cooled by the cold refrigerant, the hot, pressurized gas is passed through it in heat exchange relationship with the cooling coils. Simultaneously, the other heat exchanger is cleared of moisture and other condensables by passing hot refrigerant gas from the compressor of the refrigeration system through its cooling coils. Before reversing the function of the heat exchangers, the flow of hot refrigerant gas to the one being defrosted is terminated and replaced with the flow of cold refrigerant to cool it in order to prevent carryover of moisture on changing stages of operation. A continuous flow of cooled, dried pressurized gas is obtained from the two heat exchangers and can be passed through a third heat exchanger provided with refrigerated coils to further chill the gas to sub-zero temperature. Prior to being passed to the third heat exchanger, the cooled gas from the two parallel heat exchangers can be cycled through a preliminary heat exchanger to effect pre-cooling of the entering hot, pressurized gas.
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