Patent ID: 8522818

Claim:
A booster valve, comprising: a housing having a signal port, an actuator port, a supply port, and an exhaust port disposed therein; an upper plug disposed within the housing; a lower plug disposed within the housing, the upper plug, the lower plug and the housing collectively defining a signal chamber which fluidly communicates with the signal port, an actuator chamber which fluidly communicates with the actuator port, and a supply chamber which fluidly communicates with the supply port; and an elongate stem extending through at least portions of each of the upper and lower plugs, the stem being rigidly attached to the lower plug and slidably attached to the upper plug; the upper and lower plugs being selectively movable between: a neutral position wherein the actuator chamber is fluidly isolated from both the supply chamber and the exhaust port; a delivery position wherein the actuator chamber fluidly communicates with the supply chamber but is fluidly isolated from the exhaust port; and a discharge position wherein the actuator chamber fluidly communicates with the exhaust port but is fluidly isolated from the supply chamber.