Gas operated infinite step valve for a reciprocating compressor

An inlet valve system for a cylinder chamber of a reciprocating compressor, comprising:

• an unloader comprising a cylindrical unloader body circumferentially disposed about a central axis of the inlet valve system and having an enclosed end opposite an open end, a central bore extending between the enclosed end and the open end within the cylindrical unloader body and defining an unloader chamber, and an inlet passage defined by the cylindrical unloader body and configured to provide fluid communication between the central bore and a location external of the cylindrical unloader body;
• a valve assembly comprising a cylindrical valve body circumferentially disposed about the central axis of the inlet valve system, and having a first end opposite a second end, a plurality of first valve passages, a plurality of second valve passages, a first connective passage, a second connective passage, a plurality of inlet valve elements disposed in a plurality of valve element ports, and a central bore ending between the first end and the second end of the cylindrical valve body and along the central axis of the inlet valve system, wherein:
• the valve assembly is disposed at the open end of the cylindrical unloader body,
• the plurality of first valve passages extend between the first end of the cylindrical valve body and the first connective passage, and each of the first valve passages has a valve seating surface adjacent the first connective passage,
• the plurality of second valve passages extend between the second end of the cylindrical valve body and the first connective passage,
• the second connective passage extends between the plurality of valve element ports and the central bore of the cylindrical valve body,
• each valve element port at least partially contains a respective inlet valve element of the plurality of inlet valve elements,
• each inlet valve element is configured to move between a closed position to an opened position by applying differential gas pressures to a front element surface of a front element portion of the inlet valve element and to a pin element surface of the inlet valve element, disengage the valve seating surface of the first valve passage adjacent the first connective passage in the opened position when applying a higher second pressure to the pin element surface than a first pressure at the front element surface and engage the valve seating surface of the first valve passage adjacent the first connective passage in the closed position by discontinuing the application of the higher pressure to the pin element surface so that the second pressure is the same as that of the cylinder chamber;
• and
• a control valve actuator comprising a control valve body circumferentially disposed about the central axis of the inlet valve system and having a first end opposite a second end, a control valve passage of the control valve body extending along the central axis of the inlet valve system, a control valve element disposed in the control valve passage, and a control pressure source fluidly coupled to the control valve passage,
• wherein the pin element surface of the inlet valve element is located between the front element surface and a rear element surface.