GB191721A - Improvements in installations of continuous working air ejectors and chiefly in railway brake installations of the automatic vacuum type with combined ejectors - Google Patents

Abstract

191,721. Freins Jourdain Monneret Soc. Anon. Jan. 12, 1922, [Contention date]. Valves controlled by pilot or relay valves.- The steam supply to the small ejector of a railway vacuum brake installation is automatically cut off when the vacuum exceeds that required by working conditions, and is opened when the vacuum falls below such limit, by means of an obturator o mounted in such steam supply passage a, e. The obturator is moved to open the small ejector steam supply passage by the pressure of the small ejector steam supply, and is moved to close it either by the main steam pressure, as shown in Fig. 1, or by atmospheric pressure, as shown in Fig. 10. A regulator R for the obturator comprises pipes g<1>, 27, 7<1>, communicating with the vacuum chamber, main steam supply and obturator respectively, diaphragms D, d, valves 18, 23, 26 and controlling springs r, 48, 29. Communication between the atmosphere and the various compartments thus formed is established through ports 13, 21, h and a restricted passage 20. The connections between the regulator and the obturator are diagrammatically represented in Fig. 1. Fig. 2 shows the construction of the regulator, which may be modified by replacing the diaphragm d by a tight-fitting piston, and Fig. 4 shows the construction of the obturator, comprising a piston 4 with a sinuous groove and a piston head 3 with packing rings. A coupling neck 5 is provided for cleaning purposes. In operation the handle 11 of the obturator is set for the working vacuum required. If this vacuum is exceeded, diaphragm D descends, valve 18 opens, chambers 12 and 19 are placed in communication, diaphragm d is lifted, valve 23 closed, valve 26 opened and the main steam passes through the chamber 24 and passage 7<1> to push the obturator into the steam passages a, e, and so to cut off the supply of steam to the small ejector. If the vacuum falls, valve 18 is caused to close by the action of the spring r, diaphragm d is depressed and the main steam supply to the chamber 24 is cut off at valve 26 and the obturator is allowed to open the small ejector steam passage. In a modification the upper portion of the regulator may be duplicated so as to give two degrees of sensitiveness for convenience in working with two degrees of vacua, e.g. when the locomotive is coupled to passenger stock or to goods wagons. In a second modification the obturator and the regulator are combined in a single apparatus actuated and functioning in a similar manner to the separated apparatus. In Fig. 10 is shown a diagrammatic view of an arrangement wherein the operating fluid acting on the obturator comprises air at atmospheric pressure. In this con. struction when the desired vacuum is exceeded, the main diaphragm D opens the valve 18, which causes the diaphragm d to rise to close the passage 44 and consequently to establish a vacuum in the chamber 6' so that atmospheric pressure acting on the other side of the piston 4 pushes the obturator in to close the small ejector steam supply. When the vacuum falls below the required limit, springs r and 48 close the valve 18 and, as air enters the chamber 19 through the restricted orifice 20, the passage 44 is opened and atmospheric pressure is established on the right-hand side of the piston head 4 so that the obturator may be pushed out of the steam passage by the steam passing to the small ejector.