Patent ID: 7481073

Claim:
A multistage valve system for delivering expanded refrigerant to an air/gas dryer device comprising: a multistage parallel combination of conventional mechanical refrigerant feed injection valves having at least a first stage and a second stage, each stage receiving superheat inputs wherein said first stage has a first output capacity that is at least about two times a capacity of a second output capacity of said second stage, and wherein said first stage has a first output valve position set in response to said superheat input and said second stage has a second output valve position set in response to said superheat input, respectively, and wherein said first output capacity of said first stage is 85 to 90% of the refrigerant capacity needed for the entire valve system and, said output capacity of said second stage is 20 to 25% of the refrigerant capacity needed for the entire valve system; and wherein said first output valve position is set at a lower superheat setting than said second output valve position such that as the capacity of said first stage is exceeded, the superheat will rise to the setting of the second stage causing the second stage to make-up the remaining capacity needed for the entire valve system.