Stepped scroll compressor with staged capacity modulation

Abstract

A scroll compressor has a stepped wrap such that there is a greater height outer portion and a lesser height more central portion. Bypass ports are associated with the transition zone between the higher and lesser height portions. By providing the bypass port in a stepped scroll compressor, greater reductions in capacity can be achieved than have been provided in the prior art.

1 . A scroll compressor comprising:
 a first scroll member having a base and a generally spiral wrap extending from the base, and a second scroll member having a base and a generally spiral wrap extending from the base, said second scroll member being driven by a shaft to orbit relative to said first scroll member;   said wraps of said first and/or second scroll members having an outer greater height portion and a more central lesser height portion; and   bypass ports for communicating compression chambers defined between said wraps of said first and second scroll members back to a suction chamber of the compressor, such that a lower capacity can be provided by said scroll compressor, and valves controlling the opening and closing of said bypass ports, said valves being electric valves.   
   
   
       2 . (canceled) 
   
   
       3 . The scroll compressor as set forth in  claim 1 , wherein said bypass ports are formed in said base of said second scroll member. 
   
   
       4 . A scroll compressor comprising:
 a first scroll member having a base and a generally spiral wrap extending from the base, and a second scroll member having a base and a generally spiral wrap extending from the base, said second scroll member being driven by a shaft to orbit relative to said first scroll member;   said wraps of said first and second scroll members having an outer greater height portion and a more central lesser height portion; and   bypass ports for communicating compression chambers defined between said wraps of said first and second scroll members back to a suction chamber of the compressor, such that a lower capacity can be provided by said scroll compressor, valves provided to control the opening and closing of the bypass ports, and said bypass ports formed in said base of said second scroll member, said valves being solenoid valves.   
   
   
       5 . The scroll compressor as set forth in  claim 4 , wherein said solenoid valves are controlled to open the bypass ports to reduce the capacity of the scroll compressor. 
   
   
       6 . The scroll compressor as set forth in  claim 1 , wherein said electric valves are controlled to open the bypass ports to reduce the capacity of the scroll compressor.