GB955414A - Improvements relating to a vent valve device for compressed fluid braking apparatus - Google Patents

Abstract

955,414. Fluid pressure brake systems. COMPAGNIE DES FREINS ET SIGNAUX WESTINGHOUSE. May 10, 1960 [May 15, 1959], No. 16434/60. Addition to 850,450. Heading F2F. A braking system has a vent valve comprising chambers 6, 7 connected to an auxiliary reservoir and brake cylinder respectively, a vent passage 34, 33, 41, 40, 36, a piston 25 controlling a valve 11 to close a passage 5 between chambers 6, 7 and slidably contained in a piston 23 which closes the vent passage, the piston 25 having a ported hollow rod 25a slidable in a tube 31 and carrying the valve 11, a valve rod 26 having a section of reduced diameter being slidable within the rod 25a and carrying an upper movable valve seat 27, and a manually operable member 19 by which the valve rod 26 can be moved to connect the auxiliary reservoir and control reservoir (connected at 38) to atmosphere if the brake pipe (connected at 37) is pressurized and, if absent, cause the force applied to valve rod 26 to be transmitted to pistons 23, 25 and valve 11 to close passage 5 whereby any overcharging of the braking system can be reduced or partially or totally vented. Operation to reduce overcharging when brake pipe is pressurised. Slight momentary pressure on member 19 raises rods 20, 26 only, to move seat 27 from valve 11 to connect the brake cylinders and auxiliary reservoir to atmosphere via chambers 6, 7, aperture 46, the gap between tube 31 and rod 25a, port 43 and outlet 35. The control reservoir connected to port 38 is vented via ports 42, 44, 47, 45, 43. To vent the brake cylinder only when brake pipe is vented; a slight momentary pressure on member 19 raises rod 26 and piston 23 against spring 28, the brake cylinder being vented via passage 33, 34, 39, 41, 40, 36; the air from the brake cylinder acts on pistons 23, 25 until valve 11 engages seat 32, auxiliary reservoir pressure maintains valve 11 closed. To vent the whole apparatus.-Lever 19 is maintained in its actuated position, the seat 27 is held from valve 11 which engages seat 32, the auxiliary reservoir and brake cylinder being vented via port 46, the passage between rods 26, 25a, passage 5, and passage 34, 33, 41, 40, 36, the control reservoir being vented via ports 42, 44, 47, 45 and then as the auxiliary reservoir. To recharge the apparatus.-Pressure in the brake pipe moves piston 23 down to close port 40; eventually when the pressure on piston 25 is greater than that on valve 11 the piston 25 moves down to return valve 11 to seat 30 and seat 27 engages valve 11. In Figs. 6 and 7, not shown, the vent valve is mounted in various ways with respect to the brake pipe, brake cylinder, auxiliary and control reservoirs, and the distributer and triple valves.