Recirculating rotary gas compressor

A positive displacement recirculating rotary compressor comprising:

• a housing having two mutually opposing cylindrically curved interior side walls;
• said housing including a gas inlet port at one end located between said mutually opposing cylindrically curved side walls and a gas outlet port located at the opposite end of said housing from said inlet port and also located between said mutually opposing cylindrically curved interior side walls;
• said gas outlet port opening into a discharge manifold having a gas discharge port;
• said housing further including first and second gas recirculation ports formed respectively in said cylindrically curved opposing side walls between said inlet port and said outlet port;
• first and second involutely lobed impellers journalled for rotation in opposite directions within said housing;
• each of said impellers having at least four lobes;
• said impellers being intermeshed so as to form a high-impedance seal when said impellers are rotated in opposite directions;
• first and second recirculation conduits connecting said manifold with said first and second recirculation ports, said recirculation ports opening onto said interior walls of said housing at an acute angle with respect to said interior surface walls of said housing, whereby gas entering said housing through said recirculation ports enters in a direction approximating the direction of travel of said impellers;
• said inlet port and said outlet port being approximately equal in size to one another;
• said outlet port being approximately twice the size of each of said recirculation ports;
• said inlet, said outlet and said recirculation ports being isolated from direct fluid communication with one another and further being as large as possible within the constraints of the foregoing size relationships;
• whereby a portion of gas discharged from said housing through said outlet port is returned to said housing through said recirculation ports so as to reduce heating of said impellers;
• and with the sizing of said inlet, outlet and recirculation ports thereby resulting in minimal flow losses.