Patent GB-211856-A (GB)
Title: Train control valve construction
IPC: B60T13/66
Filed: 1924-02-11
Abstract: 211,856. Shadle, C. F. Feb 26, 1923, [Convention date]. Fluid-pressure. - An electropneumatically controlled venting-valve for a train control system is adapted to exhaust a fluid-pressure conduit to a predetermined total pressure by an intermittent puffing or " popping " action, the exhaust being effected through one or both of two pressure-retaining valves so that the rate of effecting the exhaust may be varied. As shown in Fig. 8, the venting-valve comprises a slide-valve 12 controlling communication between a pipe 14, which may be connected through the driver's valve to the brake train pipe, and either a pipe 13, which may be the feed train pipe, or a. pipe 15 leading to a pressure-retaining " pop " valve 16 and through a valve 19 and chamber 117 to a similar valve 18, whilst a fluid-pressure pipe 125 may simultaneously be connected to the two valves. Normally the valve 12 is retained in the position shown by air supplied from a high pressure pipe 26, which may contain air at main reservoir pressure, through an electropneumatic valve 23 and pipe 29 to a chamber 30 at the left-hand side of a piston 11, so that the pipes 13, 14 are in communication and the exhaust pipe 15 is cut off. Normally, also, the valve 19 is held closed by air supplied from the pipe 26, through an electropneumatic valve 20 and pipe 28 to the upper face of a piston 83, Fig. 4, the valves 20, 23 both being energized. If the valve 23 is de-energized, air exhausts from the chamber 30 through the pipe 29 and valve 23, and the piston is moved to the left by the pressure from tie pipe 13 and takes up the position shown in Fig. 5, so that the pipe 14 is exhausted through ports 120 - - 122, passages 40, 41, pipe 15 and valve 16, whilst the pipe 125 also exhausts through the port 122, passages 40, 41, pipe 15 and valve 16. If both the valves 20, 23 are de-energized, the air above the piston 83 exhausts through the pipe 28 and valve 20, and the piston rises under the pressure of a spring 84 to open the valve 81, so that the air from the pipes 14, 125 can then exhaust not only through the valve 16, but also through the passages 80, 70 and 117 and the valve 18. The valves 16, 18 are of a known construction shown in Fig. 4, and each comprises a spring-loaded valve 56, which, when raised by excess pressure in a chamber 61, vents air through ports 63 until the fall of pressure allows the spring 58 to move the valve downwardly to close the ports 63 and connect the chambers 64, 65 through the passage 62, and the outlets 66 from the chamber 65 being restricted, the pressure therein rises and assists the closing action. The construction is such that the valve opens and closes repeatedly until the pressure in the chamber 61 has fallen to the value for which the valve is set. The control valves 20, 23 are also of a known construction shown in Fig. 7, the passages 25, 29 being normally connected through a valve 94 when an armature 109 is attracted by a solenoid 106, whilst de-energization of the solenoid results in the closing of the valve 94 and the opening of a valve 100 to vent the pipe 29 to atmosphere through the ports 103.