GB838585A - Quick-action release and braking valve for vacuum brakes - Google Patents

Abstract

838,585. Vacuum brakes. KNORR-BREMSE G.m.b.H. Aug. 26, 1958 [Aug. 30, 1957], No. 27358/58. Class 103 (1). A quick-action release and braking valve 1 for an automatic vacuum brake having a twochamber brake cylinder 27, comprises a diaphragm 5 separating a chamber 9, connected to the lower brake cylinder chamber 25, from a chamber 15 connected to brake pipe 39. For braking, an increase in brake pipe pressure moves diaphragm 5 and a rod 7 down to open a valve 11 to admit atmosphere pressure to chambers 9 and 25, valve 11 closing when the pressures in chambers 9 and 15 equalize. For quick release, increase in vacuum in the brake pipe moves diaphragm 5 upwards and rod 7 opens a valve 21 to connect the upper and lower brake cylinder chambers 29, 27 via pipe 23, valve 35 and chambers 19, 17 for rapid pressure equalizing and brake release. The valve 1, brake cylinder 27 and reservoir 31 are initially evacuated from the brake pipe 39 via non- return valve 41 and chamber 17. Should the quick release not be required, e.g. on trains only partially equipped with valves 1, then valve 35 is rotated to block the pipe 23 to chamber 19, so that on brake release the vacuum in the brake pipe acts through non-return valve 37 and valve 35 to the lower chamber 25, brake application being as before. The inlet valve 11 may be throttled for more uniform braking, and a choke 43 may be inserted between valve 41 and chamber 17 to produce the release process as a function of time by controlling the rate of flow of air from chamber 17 to pipe 39 after equalization of brake cylinder chambers 25 and 29.