Patent ID: 7111470

Claim:
A variable evaporator control refrigerated compressed gas dryer comprising: a. an evaporator heat exchanger having a first flow path for compressed gas at a first temperature; b. said evaporator heat exchanger having a second flow path for a refrigerant at a second temperature which is lower than said first temperature to cool said compressed gas to a third temperature; c. a compressor to circulate said refrigerant at a predetermined pressure, said predetermined pressure having a correlation to said second temperature; d. a temperature sensor to sense said third temperature at an outlet of said first flow path, wherein said temperature sensor positioned at a single location to sense a fourth temperature wherein said fourth temperature is representative of said third temperature when a compressed gas load is above a certain level, and representative of said second temperature when said compressed gas load is below said certain level; e. a valve intermediate said second flow path and a source of refrigerant, said valve controllable to admit refrigerant into circulation to adjust said predetermined pressure; and f. a controller connected to receive feedback from said temperature sensor indicative of said third temperature, said controller controlling said valve to adjust said predetermined pressure and thus adjust said second temperature to generally maintain said third temperature at a desired value, wherein said controller connected to receive feedback from said temperature sensor indicative of said fourth temperature to control said valve to adjust said predetermined pressure and thus said second temperature such that said fourth temperature is generally maintained at said desired value; and g. a smooth tube evaporator heat exchanger.