Variable inlet guide vanes for a compressor

Claim 2

An axial flow compressor having a frame defining an annular path for axial flow of a fluid and a plurality of radially extending, circumferentially spaced vanes, each of said vanes being rotatably mounted at its radially outer end, said compressor having means for rotating and positioning said vanes in unison about their respective axes of rotation between a first and a second position, each of said vanes having radially inner ends subject to deflection and vibration due to aerodynamic forces of said fluid, a frame portion disposed radially inward of each of said vanes arranged to limit movement of the radially inner end thereof, and a projection on the end of each of said vanes forming clearances with said frame portion, such that deflection of the vane inner ends under aerodynamic forces of the fluid on said vane is restrained by said projection contacting the frame portion, characterized by said projection being eccentrically offset with respect to the vane axis of rotation by a preselected amount and in a preselected direction to cause said projection to provide restraining force on the vane inner ends when the vane is rotated from the first position to the second position.

Claim 3

A compressor according to Claim 1, wherein said projection is arranged so that when the vane is rotated to the second position, said projection contacts said frame portion at substantially the same location as that toward which the vane is deflected by said fluid in said second position.

Claim 4

An axial flow compressor having a frame defining an annular path for axial flow of a fluid and a plurality of radially extending circumferentially-spaced guide vanes, each of said guide vanes having a spindle and being rotatably mounted on said spindle at the vane radially outer end, said compressor having means for rotating and positioning said vanes in unison about the axes of said spindles between an open and a closed position, each of said vanes having radially inner ends subject to deflection and vibration due to aerodynamic forces of said fluid, a bushing disposed in said frame radially inward of each of said vanes, and a button on the end of each of said guide vanes contained within and forming clearances with the bushing walls, whereby deflection of the vane inner ends under aerodynamic forces of the fluid on said guide vane in its closed position is limited by said button contacting the bushing walls, characterized by said button being eccentrically offset with respect to the guide vane spindle by a pre-selected amount and in a pre-selected direction to cause the button to provide restraining force on the vane inner ends when the vane is rotated to said open position similar to the restraining force produced by the aerodynamic forces on said guide vane in its closed position.

Claim 5

An axial flow compressor having a frame defining an annular path for axial flow of a fluid and a plurality of radially extending circumferentially-spaced guide vanes, each of said guide vanes having a spindle and being rotatably mounted on said spindle at the vane radially outer end, said compressor having means for rotating and positioning said vanes in unison about the axes of said spindles between an open and a closed position, each of said vanes having radially inner ends subject to deflection and vibration due to aerodynamic forces of said fluid, a bushing disposed in said frame radially inward of each of said vanes, and a button on the end of each of said guide vanes contained within and forming clearances with the bushing walls, whereby deflection of the vane inner ends under aerodynamic forces of the fluid on said guide vane in its closed position is limited by said button contacting the bushing walls, characterized by said button being eccentrically offset with respect to the guide vane spindle by a pre-selected amount and in a pre-selected direction to cause the button to provide restraining force on the vane inner ends when the vane is rotated to said open position similar to the restraining force produced by the aerodynamic forces on said guide vane in its closed position.

Claim 6

A compressor according to Claim 3, wherein said button is a cylindrical radially extending projection formed on the end of said guide vane, and wherein said bushing is a circular hole forming a substantially uniform annular clearance with the button in the absence of fluid flow, said button being offset from the vane axis in a downstream direction on the vane with respect to the fluid flow entering the compressor.

Claim 7

A compressor according to Claim 4, and wherein said annular clearance is in the range of 0.25 to 1.25 mm and, wherein said offset is in the range of 1.78 to 3.05 mm.

Claim 8

A compressor having a frame (20) defining a fluid flow path (26) and a plurality of vanes (12) extending across said flow path and each rotatably mounted to the frame at one end (16), said compressor having means for rotating and positioning said vanes in unison about their respective axes of rotation between a first and a second position, the other end of each vane being subject to deflection and vibration due to aerodynamic forces of said fluid, and a frame portion (24) disposed adjacent said other end of each of said vanes being arranged to limit movement of that end by engagement with a projection (34) provided on that end of the vane and forming a clearance with said frame portion such that deflection of said other end of the vane under aerodynamic forces of the fluid on the vane is restrained by said projection contacting the frame portion, characterized by said projection being eccentrically offset (36) with respect to the vane axis of rotation (18) by a preselected amount and in a preselected direction to cause said projection to provide restraining force on the vane inner ends when the vane is rotated from the first position to the second position.

Claim 9

A compressor having a frame (20) defining a fluid flow path (26) and a plurality of vanes (12) extending across said flow path and each rotatably mounted to the frame at one end (16), said compressor having means for rotating and positioning said vanes in unison about their respective axes of rotation between a first and a second position, the other end of each vane being subject to deflection and vibration due to aerodynamic forces of said fluid, and a frame portion (24) disposed adjacent said other end of each of said vanes being arranged to limit movement of that end by engagement with a projection (34) provided on that end of the vane and forming a clearance with said frame portion such that deflection of said other end of the vane under aerodynamic forces of the fluid on the vane is restrained by said projection contacting the frame portion, characterized by said projection being eccentrically offset (36) with respect to the vane axis of rotation (18) by a preselected amount and in a preselected direction to cause said projection to provide restraining force on the vane inner ends when the vane is rotated from the first position to the second position.