Adjustable-inlet radial-radial compressor

Abstract

A radial-radial compressor includes an inlet-adjustment mechanism in an air inlet for the compressor, operable to move between an open position and a closed position in the air inlet. The inlet-adjustment mechanism includes a tubular sleeve that is movable in the air inlet with an axial component of movement for adjusting a spacing distance of a trailing edge of the sleeve from an inducer portion of the wheel. In an “on” position the spacing distance is relatively greater, while in the “off” position the spacing distance is relatively smaller and the sleeve therefore reduces an effective inlet area into the inducer portion of the wheel, relative to the effective inlet area in the “on” position.

What is claimed is: 
     
         1 . A radial-radial compressor comprising:
 a compressor housing and a radial-radial compressor wheel mounted in the compressor housing and connected to a rotatable shaft for rotation therewith, the radial-radial compressor wheel having a hub and having blades joined to the hub and extending therefrom and terminating at outer tips of the blades, the compressor housing defining an air inlet for leading air in a generally axial direction toward the radial-radial compressor wheel and defining a shroud surface that is adjacent to the outer tips of the blades, the hub of the radial-radial compressor wheel being configured to cooperate with the shroud surface to cause air proceeding through the air inlet to be turned substantially 90 degrees toward a generally radially outward direction relative to a rotational axis of the radial-radial compressor wheel, the blades defining an inducer portion arranged to receive air proceeding in the generally radially outward direction, the compressor housing further defining a volute for receiving compressed air discharged generally radially outwardly from the radial-radial compressor wheel; and   an inlet-adjustment mechanism disposed in the air inlet upstream of the radial-radial compressor wheel and movable between an open or “on” position and a closed or “off” position for adjusting an effective inlet area at the inducer portion of the radial-radial compressor wheel, the inlet-adjustment mechanism comprising a tubular sleeve that is movable within the air inlet with an axial component of movement, the tubular sleeve having a trailing edge spaced by a spacing distance upstream from the compressor wheel, the axial movement of the tubular sleeve being effective to adjust the spacing distance of the trailing edge from the compressor wheel, wherein in the closed or “off” position of the inlet-adjustment mechanism the spacing distance is relatively smaller, and in the open or “on” position the spacing distance is relatively greater, the spacing distance in the “on” position being such that the effective inlet area into the inducer portion of the compressor wheel is defined by the hub of the compressor wheel and the shroud surface of the compressor housing, the spacing distance in the “off” position being such that the effective inlet area into the inducer portion of the compressor wheel is defined between the hub and the trailing edge of the tubular sleeve.   
     
     
         2 . The radial-radial compressor of  claim 1 , further comprising an actuation system for causing movement of the tubular sleeve between the “off” and “on” positions. 
     
     
         3 . The radial-radial compressor of  claim 2 , wherein the actuation system comprises a lead-screw arrangement. 
     
     
         4 . The radial-radial compressor of  claim 3 , wherein the lead-screw arrangement includes an external helical first thread on the tubular sleeve, and a drive cog having a helical thread meshed with the first thread on the tubular sleeve, rotation of the drive cog about an axis thereof imparting a screw motion to the tubular sleeve so as to adjust said spacing distance. 
     
     
         5 . The radial-radial compressor of  claim 4 , wherein the lead-screw arrangement further comprises a nut having an internal helical thread, and the tubular sleeve includes an external helical second thread axially spaced from the first thread, the thread of the nut meshing with the second thread of the tubular sleeve, the nut guiding the screw motion of the tubular sleeve and keeping the tubular sleeve substantially coaxial with the compressor wheel. 
     
     
         6 . The radial-radial compressor of  claim 2 , wherein the actuation system comprises a rack-and-pinion arrangement. 
     
     
         7 . The radial-radial compressor of  claim 6 , wherein the rack-and-pinion arrangement includes an axially extending rack on the tubular sleeve, the rack having axially spaced teeth, and a drive pinion having a rotation axis extending perpendicular to the axial direction, the drive pinion having teeth meshed with the teeth of the rack, rotation of the drive pinion imparting axial motion to the tubular sleeve.