Patent GB-1060230-A (GB)
Title: Fluid flow control valves
IPC: F16K31/42
Filed: 1964-12-04
Abstract: 1,060,230. Valves. CONCORDIA MASCHINENUND ELEKTRIZIT€TS G.m.b.H. Dec. 4. 1964 [Dec. 11, 1963; Oct. 17, 1964], No. 49421/64. Heading F2V. With pilot valves 29, 29<SP>1</SP>, Fig. 1, in the closed  position shown, the series-connected mainvalves 2, 2<SP>1</SP> controlled thereby connect a working port 21 to an exhaust port 19 whilst the supply pressure from a port 22 traverses on adjustable throttle 28 in a line 26 and enters a chamber 14<SP>1</SP> of a movable closure-member 8<SP>1</SP>, forming part of valve 2<SP>1</SP>, from whence it flows via a channel 23 to a chamber 16 of a movable closure-member 8 forming part of valve 2, the chamber 16 being isolated from a leakage passage 25 by the member 8. The main valves also include closure members 3, 3<SP>1</SP> and 4, 4<SP>1</SP>. Simultaneous energization of the three-way pilot-valves directs fluid from the line 26 to depress pistons 5, 5<SP>1</SP> so opening closure members 4, 4<SP>1</SP>, seating closure members 3, 3<SP>1</SP>, and moving closure members 8, 81 from seats 15, 15<SP>1</SP> on to seats 39, 39<SP>1</SP>. The working port 21 is thereby cut-off from the exhaust port 19 and connected to the supply port 22. Should one of the main valves 22<SP>1</SP> fail then the line 26 is connected to the leakage line 25 via the  chamber 14 or 14<SP>1</SP> of the defective valve so that  the functioning valve is returned to the position  shown because the quantity of fluid passing the throttle 28 is less than that discharged from the leakage line 25 and the pressure on the pistons 5, 5<SP>1</SP> is insufficient to overcome the valve springs 12, 12<SP>1</SP>. The closure members 3, 4 have throttling plugs 40, 41. A second and identical valve arrangement 1<SP>1</SP> may be mounted adjacent to or directly connected with the one described, the port 21 and line 26 opening thereinto whilst the two latter may be connected by a check-valve 38. In a modification, the passages 51 and 111, Fig. 2, leading to and from the exhaust and working ports contain adjustable throttles 61, 113, respectively, whilst the line 123 connecting the passage 111 with the pilot valves 47, 58 include restrictors 114, 118 and buffer chambers 117, 50; a restrictor 105 is also disposed in a bypass 101 across the adjustable throttle 104 in a branch supply line 107. The valve stems are sealed by both selflubricating rings 77, 108, which may support rubber rings, and bushings 74, 128 with annular grooves 76, 129 therebetween which open to valve chambers 127, 91 via radial bores 75, 110 whereby the annular grooves are flushed by the controlled fluid each time the valves are operated. The valves are actuated by fluid pressure on diaphragms 63, 124. The valve closures 79, 83, 98 and 100 are associated with 0-rings 78, 84 and 97 which allow limited lostmotion between these closures and their valve stems. The restrictors 114, 118 ensure that insufficient pressure will be available to operate the main valves should one of the pilot valves fail since the working port will remain open to exhaust via the related main valve. Two such units are oppositely connected, one unit controlling a brake and the other a clutch, the throttle 113 of the clutch control-valve is positioned to exert a greater degree of restriction than the corresponding throttle of the brake control-valve.