US Patent 7967582 Compressor having capacity modulation system

A compressor includes a first porting extending through an end plate of an orbiting scroll member at an angular extent of at least twenty degrees and first and second spiral wraps defining modulated capacity pockets when the orbiting scroll is in a first position. The first modulated capacity pockets may include a set of radially outermost compression pockets located radially inward relative to the first porting and isolated from communication with the first porting during an entirety of the compression cycle. The first porting may align with the second spiral wrap at a location radially outward from and directly adjacent the first modulated capacity pockets when the orbiting scroll member is in the first position.