US Patent 8079808 Geared inlet guide vane for a centrifugal compressor

A compressor assembly has a fluid inlet positioned to facilitate the passage of a fluid. The compressor assembly includes a compressor housing defining a compressor inlet and an impeller rotatably supported at least partially within the compressor housing. The impeller includes an inducer portion. A fluid treatment member is disposed adjacent the compressor housing and between the compressor inlet and the inducer portion and an inlet vane assembly I disposed adjacent the compressor inlet and includes a plurality of vanes. Each of the vanes is movable between a first position and a second position to control the quantity of fluid that passes to the impeller.