Patent GB-810465-A (GB)
Title: Relay valve
IPC: F15B13/043
Filed: 1955-11-10
Abstract: 810,465. Fluid-pressure servomotor-control systems; valves. BENDIX AVIATION CORPORATION. Nov. 10, 1955 [Nov. 15, 1954], No. 32207/55. Class 135. A relay valve 14 for a fluid-pressure servo system comprises a ported plate 48, Fig. 3, movable within an aperture in a fixed plate 46 held between two further fixed plates 30, 94, two fluid-pressure passages 78, 79 extending internally through the plate 48 and opening on opposite sides thereof into fluid-pressure chambers 80, 82, two orifices 74, 75 communicating with the respective passages 78, 79, and means, such as the flapper mechanism 84, movable relative to the orifices to produce a pressure differential between the passages 78, 79 and hence between the chambers 80, 82 so that the plate 48 moves in a direction to equalize the pressures at the orifices and in the chambers. The base-plate 30 has an inlet opening 32 provided with a bush 38 which separates channels 34, 36, an exhaust opening 44, and ports 40, 42 connecting the channels 34, 36 through pipes 16, 18, Fig. 1, with the opposite sides of a servo-piston 22 operating on a load 26. The movable plate 48 has through ports 50, 52, 54, 56 which in its neutral position coincide with the ports or openings 32, 40, 42, 44 respectively. The port 56 is fitted with a bush 62, Fig. 6, separating channels 58, 59 on its upper side and channels 60, 61 on its under side. Ports 64, 66 opening inside the port 50 are in free communication with the passages 78, 79 and the orifices 74, 75 respectively. Spaces 76, 77, 120, 122 as well as the chambers 80, 82 are left between the plates 46 and 48. The top plate 94 has ports 96, 104, 106, 108 coinciding with the ports 50, 52, 54, 56 when the plate 48 is in its neutral position. The upper ends of the ports 96, 108 are plugged, and a bushing 102 in the port 96 separates channels 98, 100. The plate 94 also has a recess 110 to accommodate flapper arms 90, 92 carried by a yoke 88 on the flapper assembly. The recess 110 communicates by two internal passages in the plate 94 with ports 116, 118 opening into the spaces 120, 122. The flapper arms 90, 92 differentially control the orifices 74, 75. The flapper assembly is. enclosed by a housing 124, Fig. 1, and operated by a torque motor 28 secured to the relay valve 14. An internal passage 81, Fig. 7, connects the spaces 120, 122 to the interior of the bush 62 and hence to the exhaust line 12. A fluid pressure supply line 10 is connected to the bush 38. When the flapper assembly moves to obturate the orifice 74, pressure increases in the chamber 80 and the plate 48 moves to the right as shown in Figs. 9A, 9B so that orifices 136, 138 are formed connecting the port 50 and hence the inlet opening 32 with the channels 36 and 100 and therefore with the outlet port 42. Similarly, orifices 140, 142 are formed between the ports 44, 108 and the respective channels 60, 58, whereby the other outlet 40 is connected to the exhaust opening 44. The invention is also applicable to a valve having a flat plate of arcuate form having limited rotary movement about an axis perpendicular to the plate or to a slightly cambered or part cylindrical plate having limited movement about its centre of curvature.