Patent ID: 7882826

Claim:
A rotor apparatus for a compressor assembly having a housing defining an inlet port, outlet port, and a rotor cavity in communication with the inlet port and outlet port, the rotor apparatus comprising: first and second rotors each having a respective plurality of lobes formed thereon and rotatably mountable adjacent one another within the rotor cavity of the housing; wherein each of said first and second rotors has a respective first end substantially adjacent to the inlet port and a respective second end substantially adjacent to the outlet port when mounted within the housing; wherein each of said plurality of lobes has a respective outer radius; and wherein said outer radius R 1 of each of said plurality of lobes at said first end is greater than said outer radius R 2 of each of said plurality of lobes at said second end when said first and second rotors are mounted within the housing; wherein said respective outer radius R 1 , R 2 of each of said plurality of lobes and said housing define a respective clearance C 1 , C 2 therebetween that is greater at said second end than at said first end when said first and second rotors are mounted within said housing; wherein the clearance between each of the lobes of said first and second rotors and said housing as provided by said outer radius R 2 of each of said lobes at said respective second end of said first and second rotors is said clearance C 2 .