GB1366595A - Valve device for controlling operation of a brake cylinder - Google Patents

Abstract

1366595 Relay valves; rail vehicle braking systems KNORR-BREMSE GmbH 21 Dec 1972 [28 Dec 1971] 59259/72 Heading F2F A railway vehicle compressed air braking system includes a valve device 2 for controlling the operation of a brake cylinder 40 in response to pressure changes in a main air line 5; the device 2 comprises a control piston 3 separating a control chamber 4 from an admission chamber 6 connected to the line 5, the piston 3 being connected by a rod 8 to a valve packing 9 of a bleed valve 9, 13 which controls admission of compressed air to a bleed chamber 11 and the packing 9 carries a valve tube 31 which is movable to actuate an inlet valve 42, 43 and an outlet valve 43, 46 to connect an auxiliary reservoir 44 to the brake cylinder 40 to give brake actuation. The valve packing 9 is disposed in a chamber 10 connected to the admission chamber 6 via a duct 110 and the valve seat 13 is formed on a control sleeve 12 having an interior duct 17 which includes a throttle 21. The sleeve 12 defines piston surfaces 15, 22 and is guided in the housing 1 with a small gap therebetween constituting a throttle passageway. A tappet 24 extends perpendicular to the sleeve 12 and is connected to an auxiliary piston 25 which separates two chambers 26, 27 connected respectively to bleed chamber 11 and to chamber 6: the piston is adapted to slide over a throttle duct 66. The valve tube 31 is secured to a piston 37 separating chambers 38, 39: chamber 38 is connected to atmosphere whilst chamber 39 is connected to brake cylinder 40 via a duct 39 and to a chamber 57 via a duct 56. Duct 39 is also connected to a chamber 48 separated by a piston 50 from a chamber 50 and piston 49 is actuable via a plunger 51 on a shut off valve 53 in a throttle duct 55 between chambers 4, 6. The chamber 57 is defined by a piston 58 which is actuable on a valve 60, to control connection of bleed chamber 11 to atmosphere via a duct 63 and a transmission chamber 62. Operation.-To brake the vehicle a pressure drop is introduced into line 5 whereupon piston 3 moves upwardly to open valve 9, 13, sleeve 12 being held in position by tappet 24. Compressed air then leaves the chamber 6 via duct 110, bleed valve 9, 13, duct 17, the passageway between sleeve 12 and housing 1, as well as bleed chamber 11 and also through the duct 28 into the chamber 26 and through the duct 63 into the chamber 62. The flow away of compressed air through valve 9, 13 allows piston 3 to be raised to an increased extent, and valves 42, 43, and 46, 43 are actuated to connect cylinder 40 to reservoir 44, and disconnect chamber 39 from atmosphere. Pressure in chamber 26 pushes piston 25 and tappet 24 rightwards so that sleeve 12 can move towards valve packing 9 just before pressure equilibrium is established between chambers 6, 11, valve 60 having been closed by pressure in chamber 57.