Gas operated unloader valve

An unloader valve for use with a reciprocating gas compressor having a compression space defined by a piston and a cylinder, the unloader valve comprising:

• a seat including a plurality of inlet apertures;
• a manifold plate fixedly connected to the seat, the manifold plate including
• a plurality of outlet apertures,
• a plurality of plug holes;
• a control chamber formed in the manifold plate;
• and
• a control space fully defined by the manifold plate and arranged to fluidly connect the control chamber and each of the plug holes to one another;
• a control member disposed within the control chamber and movable between a first position in which the control space is exposed to the compression space, and a second position in which the control space is isolated from the compression space;
• and
• a plurality of plugs, each plug positioned within one of the plug holes, each plug movable from a closed position in which each plug closes one of the inlet apertures to an open position in response to the control member being disposed in the first position and a pressure within the control space being below a predetermined pressure, and wherein each plug is maintained in the open position in response to the control member being in the second position.

An unloader valve for use with a reciprocating gas compressor having a compression space defined by a piston and a cylinder, the unloader valve comprising:

• a seat including a plurality of inlet apertures;
• a manifold plate including a plurality of outlet apertures and a plurality of attachment apertures;
• a control seat threadably coupled to the manifold plate to fixedly attach the seat and the manifold plate;
• an interface plate positioned between the seat and the manifold plate and cooperating with the manifold plate to define a control space;
• a plurality of valve cups, each valve cup threadably connected to the manifold plate and operable to sandwich the interface plate between the valve cups and the manifold plate;
• a control member disposed within the control seat and movable between a first position in which the control space is exposed to the compression space, and a second position in which the control space is isolated from the compression space;
• and
• a plurality of plugs, each plug positioned within one of the valve cups, each plug movable from a closed position in which each plug closes one of the inlet apertures to an open position in response to the control member being disposed in the first position and a pressure within the control space being below a predetermined pressure, and wherein each plug is maintained in the open position in response to the control member being in the second position.