Patent GB-190614487-A (GB)
Title: Improved Triple Valve Devices for Fluid Pressure Brakes.
Filed: 1906-06-25
Granted: 1907-05-02
Abstract: 14,487. Westinghouse Brake Co., [Westinghouse Air Brake Co.]. June 25. Brakes.-To permit of a more certain graduated release of compressedair brakes and a quick recharge of the auxiliary reservoirs, the triple valve is connected to a supplemental reservoir which, when train-pipe pressure is increased to release the brakes, discharges into the slide-valve chamber of the triple valve and the auxiliary reservoir until the pressure therein has risen sufficiently to move the triple-valve piston back to disconnect the supplemental reservoir from the auxiliary reservoir and close the brakecylinder exhaust. One form of triple valve is shown in Figs. 2-7, of which Figs. 3 and 4 show cross-sections on the lines III-III and IV-IV respectively of Fig. 2, Fig. 5 shows the slide valve seat, Fig. 6 a back view of the slide valves 18, 17, and Fig. 7 a face view of the main slide valve 17. In the release' position shown, air from the train-pipe passage 19 can feed to the slide-valve chamber 11 and the auxiliary reservoir in the usual way, and to the supplemental-reservoir passage 23, Fig. 4, through registering ports 20, 21, 22 in the slide valves 18, 17 and the slide-valve seat respectively; and the brake-cylinder passage 29 is connected to the exhaust port 33, Fig. 3, through passage 30, ports 31, 25, cavity 24 in slide valve 18, and ports 26, 32. The slide valve 18 and the ordinary graduating-valve 16 move with the piston 13, but there is some lost motion between the piston-stem 14 and the main slide valve 17, so that, when train-pipe pressure is reduced for a service application, first the valve 18 is moved to bring its cavity 24 out of register with the ports 25, 26, and so close the brake cylinder to the exhaust, and to blank the port 21 and so seal up the pressure in the supplemental reservoir, and the graduating-valve 16 is opened, after which the slide valve 17 is moved to bring its graduating- port 27 over the brake-cylinder port 28 as usual. Compressed air then flows from the auxiliary reservoir to the brake cylinder until the pressure in the former has fallen sufficiently for the piston 13 to rise and close the graduating-valve 16, but as the main slide valve does not move, the brakecylinder exhaust and the supplemental-reservoir port remain blanked. When air is admitted to the train-pipe to effect a graduated release, the triple valve is moved back to the position shown, connecting the brake cylinder to the exhaust and allowing the air in the supplemental reservoir to expand into the slide-valve chamber and the auxiliary reservoir. When the pressure in the slide-valve chamber has risen sufficiently, it moves the piston 13 down until the head on its stem 14 engages the slide valve 17, when the slide valve 18 will have closed the brake-cylinder exhaust passage and the supplemental - reservoir port 21. By repeating this operation, the brake pressure can be graded down. For a quick release, the train pipe is charged sufficiently rapidly to hold the triple valve in the release position. In an emergency application, the piston 13 compresses the spring 15, the brake-cylinder port 28 is uncovered, and the supplemental-reservoir port 22 is connected to the brake-cylinder port 31 by a cavity 34, Fig. 7, in the slide valve, so that both the auxiliary reservoir and the supplemental reservoir discharge into the brake cylinder. In a modified construction of triple valve, the slide valve 18 controls the brake-cylinder exhaust only, and the supplementalreservoir port 21 is governed by a stem valve, similar to the graduating-valve 16, carried by the piston-stem 14, so that, when the graduating-valve 16 is open, the other stem valve is closed, and vice versa. In another modification, the graduating-port 27 extends through the slide valve 17 and is controlled by a slide valve, carried by the piston-stem 14, instead of by the stem valve 16; and a check valve is inserted between the port 28 and the passage 29 to prevent back flow from the brake cylinder in emergency applications. In a further modification, Fig. 21, the port 22 leading to the supplemental reservoir 5 is governed by the main slide valve 17. In the release position shown, the brakecylinder passage 9 is connected to the exhaust 33, and the port 22 is uncovered. When train-pipe pressure is reduced for a service application, the graduating-valve 16 is drawn out, and the slide valve 17 moved to close the port 22 and briug the service port 27 over the brake-cylinder port 31, the spring 39 being compressed. When auxiliaryreservoir pressure has fallen sufficiently, the spring 39 closes the graduating-valve 16 ; or it may be arranged to move the port 27 out of register with the port 31, in which case the graduating-valve 16 may be dispensed with. When train-pipe pressure is increased for a graduated release, the triple valve moves back to the position shown, allowing the air in the supplemental reservoir 5 to flow into the auxiliary reservoir and chamber 11 and move the piston 13 out till it touches the stop 38 to close again the port 22 and the brake-cylinder exhaust. In emergency applications, the port 40 registers with the brake-cylinder port 31. With this triple valve, the supplemental-reservoir port is closed in all positions of the triple valve except the release position.