Discharge cut-off valve

An apparatus comprising:

• an air compressor including an inlet port, discharge port, an unloader port, and a piston chamber;
• an air dryer coupled to the discharge port of the air compressor, the air dryer including an output port and a control port and lacking a turbo cut-off valve;
• a supply reservoir coupled to the output port of the air dryer;
• a governor coupled to the control port of the air dryer and coupled to the unloader port of the air compressor,
• wherein the air compressor includes a cylinder head manifold including a recessed portion and a bearing face surrounding the recessed portion, the recessed portion including a discharge vent opening and an unloader vent opening, the bearing face including a plurality of inlet openings, the cylinder head manifold further including a discharge cut-off valve to selectively prevent the escape of compressed air from the discharge port of the air compressor, the discharge cut-off valve including:
• a hinged leaf valve disposed within the recessed portion of the cylinder head manifold and being rotatably anchored at a first end to a joint pin and being guided at a second end by a guide pin, the hinged leaf valve being moveable between a first position during an on-load phase and a second position during an off-load phase,
• wherein, in the first position, the hinged leaf valve is seated over an unloader vent opening while a discharge vent opening is uncovered by the hinged leaf valve, such that air from the inlet port enters the piston chamber via the plurality of inlet openings, is compressed in the piston chamber, and escapes the piston chamber via the discharge vent opening to the discharge port, and
• wherein, in the second position, the hinged leaf valve is seated over the discharge vent opening while the unloader vent opening is uncovered by the hinged leaf valve, such that air from the inlet port enters the piston chamber via the plurality of inlet openings and escapes the piston chamber via the unloader vent opening to the inlet port,
• such that the air dryer does not receive compressed air from the discharge port of the air compressor during the off-load phase.

A method comprising:

• providing an air compressor including an inlet port for attachment to a supply of boosted air and a discharge port for attachment to an air dryer lacking a turbo-cut off valve;
• during an on-load phase of operation, causing the discharge of air from the air compressor discharge port;
• during an off-load phase of operation, preventing the discharge of air from the air compressor discharge port by actuation of a discharge cut-off valve;
• wherein the discharge cut-off valve includes a hinged leaf valve that is movable between a first position during the on-load phase and a second position during the off-load phase, the hinged leaf valve being disposed in a recessed portion of a cylinder head manifold, the recessed portion including an unloader vent opening and a discharge vent opening,
• wherein, in the first position, the hinged leaf valve is seated over the unloader vent opening while the discharge vent opening is uncovered, the discharge vent opening being in fluid communication between a piston chamber and the air compressor discharge port,
• wherein, in the second position, the hinged leaf valve is seated over the discharge vent opening while the unloader vent opening is uncovered, the unloader vent opening being in fluid communication between the piston chamber and the air compressor inlet port.