Patent GB-190311981-A (GB)
Title: Improvements in Engineers' or Drivers' Valves for Operating Air Brakes on Trains of Vehicles
Inventor: CORRINGTON MURRAY
Filed: 1903-05-26
Granted: 1903-07-02
Abstract: 11,981. Corrington, M. May 26. Brakes.-The engineers' or drivers' valves of automatic fluid-pressure brake systems are directly connected with pressure-reducing valves in such a manner that, by turning the handle of the valve to the proper position, any one of a series of working pressures can be obtained in the train-pipe. The driver's valve also serves to cut-off or open communication with either the low-pressure or high-pressure element of a duplex governor, which determines the pressure at which the air pump ceases to force air into the main reservoir. Fig. 1 shows a section of the valve and its casing, Fig. 5 a plan of the seat 6, and Fig. 6 a plan of the disc valve 5, which is turned upon the seat by the handle 7. Fig. 1 shows the position of the valve when the brakes are being released. Air from the main reservoir at 17 flows through the valve port 27 and seat port 30 to the train-pipe at 18, the escape from the train-pipe to the atmosphere at 23 being closed by a valve 21 held in place by a piston 19, the pressures on the upper and lower sides of which are equalized through the valve port 37 and seat ports 42, 90. In this position, a slight but noisy escape of air through a small port 40, Fig. 6, warns the engineer that, in order to prevent the train-pipe from becoming too highly charged, he should turn the handle to position No. 2, Fig. 5, in which the air from the main reservoir cannot pass to the train-pipe directly through the valve port 27 and seat port 30, as before, but passes through the valve port 27 to the seat port 33 and thence to a pressure-reducing valve, whence it returns through a passage 35 into the train-pipe connection 18. If the handle be turned to position No. 3, the air is led through a pressure-reducing valve of different power by means of the seat port 43 and returns through a passage 44 to the train-pipe. When the train-pipe is charged and the handle is turned to position No. 4, all the ports are closed. To apply the brakes with moderate force, the handle is turned to position No. 5, when the air above the equalizing-piston 19 escapes through the seat port 90, valve port 37, seat port 38, and main exhaust port 39. The piston 19 is thus caused to rise and open the train-pipe vent 23. By turning the handle back to No. 4 position when the pressure is sufficiently reduced, the piston 19 falls again and prevents further escape from the train-pipe. To apply the brakes in an emergency, the handle is turned to No. 6 position, in which the valve cavity 29 connects the seat port 30 with the main exhaust port 39. Fig. 7 shows a modification in which an extra port 45 is formed in the seat, so that, when the handle is in the position No. 3, communication is opened between the main reservoir and a pipe 46 leading to the low-pressure governor 48 of the pump, which is thus caused to stop working when the desired pressure in the reservoir is attained. In other positions of the handle, the high-pressure governor 49 controls the pump. In other modifications, additional ports and passages are provided for connecting the valve with a third and a fourth pressure-reducing valve when a greater range in the variation of the working pressure is required.