Pneumatically driven train brake pipe pressure exhaust valve

DETAILED DESCRIPTION This invention, according to a first aspect thereof, is predicated on the development of a new, unique and simplified valve body incorporating a variable orifice type valve through which the brake pipe pressure is discharged for service brake applications, whereby the variable orifice, and accordingly the discharge rate, can be regulated by electronic control of supply and exhaust solenoids based on brake pipe pressure feedback information received by a microprocessor; and further includes a separate and distinct dump valve arrangement which opens concurrently with the variable orifice type valve for emergency brake applications.
In essence, the improved valve of this invention is intended to be incorporated into a more or less conventional radio control system for exhausting the brake pipe air pressure at the last car of the train in accordance with service, as well as emergency, brake application signals transmitted from the locomotive.
In its broadest sense, the valve apparatus comprises a regulating valve device having two distinct valves controlled by a single pneumatic control system for reducing the brake pipe air pressure in the last car, or any selected car, with the first valve being an adjustable orifice type valve adapted to controllably vent air pressure from the brake pipe when the valve is at least in a partially open position, with the rate of discharge being in proportion to the extent the valve is open for the purpose of making a service brake application to a commanded target pressure and thereafter regulating the exhaust flow to maintain the target pressure as the brake pipe pressure gradient settles out; and the second valve being a dump valve, i.
e.
, a valve capable of opening to provide a large orifice to quickly vent air pressure from the brake pipe at a more rapid rate consistent with the requirements for making an emergency brake application.
In a more specific aspect of the present invention, the regulating valve device comprises a valve body having at least one supply passage to which the brake pipe is connected, an exhaust passage open to atmosphere and a bore with which the supply passage and the exhaust passage are in fluid communication