Patent ID: 8734091

Claim:
A compressor apparatus, comprising: a compressor spool mounted for rotation about a centerline axis and carrying a plurality of axially-spaced-apart blade rows, each blade row comprising an annular array of airfoil-shaped compressor blades; a casing surrounding the compressor blades, the casing carrying a liner assembly which defines a boundary of a primary gas flowpath through the compressor; a plurality of axially-spaced-apart stator rows carried by the liner assembly, each stator row comprising an annular array of airfoil-shaped stator vanes, wherein the stator rows alternate axially with the blade rows, wherein at least some axially adjacent ones of the stator rows are variable stator rows, the stator vanes of which are mounted on trunnions passing through the casing, so as to be pivotable relative to the casing; an actuator arm coupled to each of the trunnions, outside the casing, wherein the actuator arms of a first one of the variable stator rows extend axially forward and the actuator arms of an axially adjacent second one of the second variable stator rows extend axially rearward, so as to create an open void at the exterior of the casing, which is in general axial alignment with at least one first bleed slot that passes through the liner assembly between first and second ones of the variable stator rows; a first flow path defined by the casing, communicating with the at least one first bleed slot and with an exterior of the casing; and wherein the casing includes at least one first extraction port formed at an exterior surface of the casing in flow communication with the first flow path and positioned within forward and aft boundaries of the open void in the axial direction.