Compact variable volume index valve for screw compressor background

A screw compressor comprising:

• a compressor housing defining a compression chamber having a compression chamber outlet end and a plurality of bypass ports communicating with the compression chamber;
• a spiral valve positioned adjacent the plurality of bypass ports communicating with the compression chamber, the spiral valve comprising a shutter configured to selective open and close one or more of the plurality of bypass ports based on a rotational position;
• and
• a compact variable volume index valve comprising:
• a linear valve member positioned adjacent the compression chamber outlet end of the compression chamber;
• and
• an actuator structure coupled to the linear valve member and oriented to move the linear valve member radially along the compression chamber outlet end of the compression chamber to adjust a radial location where gas exits the compression chamber,
• wherein the actuator structure is coupled to the shutter of the spiral valve of the screw compressor such that the actuator structure moves the linear valve member based on a position of the spiral valve of the screw compressor.