Interstage capacity control valve with side stream flow distribution and flow regulation for multi-stage centrifugal compressors

A method of operating a centrifugal compressor, the centrifugal compressor including a first stage impeller, a second stage impeller, and a plurality of guide vanes and a side stream injection port each respectively located between the first stage impeller and the second stage impeller, and the method comprising:

• compressing a fluid with the first stage impeller;
• directing, via channels formed by the plurality of guide vanes, an interstage flow of the fluid discharged from the first stage impeller to an inlet of the second stage impeller;
• and
• actuating a throttle ring to adjust a flow of the fluid in the interstage flow into the second stage impeller, the centrifugal compressor including the throttle ring, a drive ring, and linkage assemblies connecting the drive ring to the throttle ring, and the actuating of the throttle ring including:
• moving the throttle ring in an axial direction between a retracted position and an extended position by a rotation of the drive ring, the rotation of the drive ring causing the throttle ring to move in the axial direction, wherein
• in the extended position, flow of the side stream of the fluid through the side stream injection port is obstructed by the throttle ring and flow of the interstage fluid through the channels is partially obstructed by the throttle ring, and
• in the retracted position, the side stream of the fluid flows through the side stream injection port and into the inlet of the second stage impeller.