Patent ID: 7568898

Claim:
A compressor apparatus ( 20 ) comprising: a housing ( 22 ) assembly having first ( 53 ) and second ( 58 ) ports along a flow path and including a cast discharge case ( 56 ); one or more working elements ( 26 ; 28 ) cooperating with the housing ( 22 ) to define a compression path between a suction ( 60 ) plenum and a discharge ( 62 ) plenum along the flow path, wherein the one or more working elements include: a screw-type male-lobed rotor ( 26 ) having a first rotational axis ( 500 ); and a screw-type female-lobed rotor ( 28 ) having a second rotational axis ( 502 ) and enmeshed with the male-lobed rotor; a check valve ( 70 ) in the discharge case and having a valve element ( 72 ) having a first condition permitting downstream flow along the flow path and a second condition blocking a reverse flow; and sound suppressing means ( 120 ; 220 ; 320 ) at least partially surrounding the flow path upstream of the valve element.