Patent GB-506088-A (GB)
Title: Improvements in or relating to governor valves for fluid pressure storage devices
IPC: F16K17/04
Filed: 1938-03-12
Abstract: 506,088. Relief valves; hydraulic transmission of power. AUTOMOTIVE PRODUCTS CO., Ltd., CLENCH, E. C. S., THORNHILL, P. W., and KAHL, Q. H. H March 12, 1938, Nos. 7785 and 33347. [Classes 69 (ii) and 135] In a relief valve for liquid pressure remote control systems of the kind in which the valve body 10 has an inlet connection 31 through which liquid from a pump 34 is fed past a non-return valve 29 to a delivery connection 32, and a relief connection 18 which is opened to the inlet connection when the delivery pressure acting on the valve member 14 or a surface connected thereto exceeds a predetermined value, the valve member 14 is constituted as a slidable plunger and carries the non-return valve 29. The valve member 14, Fig. 1, comprises a closure member 17, adapted to close the relief connection 18, and two flanged portions 15, 16 movable in fluid-tight manner in bores 11, 13, of differing diameter in the valve body 10. The valve member 14 also has a plunger 20 sliding in a bore 23 and loaded by a spring 19 adjustable by means of a cap 21. The continuously running pump 34 draws its supply from a reservoir 33, and the delivery connection 32 is connected by a conduit 36 to a hydraulic accumulator 35. The latter supplies a slave unit 41 under the control of a selector valve 38, the rejected liquid returning to the reservoir 33 by a conduit 42 to which the relief connection 18 is connected by a conduit 43. The non-return valve 29 is in the form of a rubber or like resilient ring which controls ports 24 opening between the flanges 15, 16. The annular spaces 27, 28 adjacent the outer ends of the flanges communicate with one another and with the passages 24 by further passages 25, 26. The annular areas on which the inlet pressure acts in the chambers 27, 28 are such that the resultant force tends to close the valve 17. The delivery pressure in the chamber 30 however acts in the opposite direction since the bore 11 is of larger diameter than the bore 13. When the pressure in the accumulator 35 and hence in the chamber 30 rises to a predetermined high value it overcomes the effect of the inlet pressure and the valve 17 opens sharply as the pressure in the chambers 27, 28 is immediately relieved. Due to the non-return valve 29, the fluid is locked in the conduit 36 and the valve 17 does not reopen until the pressure in the accumulator 35 has fallen to a predetermined low value. In the form shown in Fig. 2, the closure part of the valve member 47 is formed as a flange 48 which houses a washer 49 seating against a flanged member 46 held between the two parts 10a, 10b of the housing. The valve member has a plunger portion 51 which operates in a bore of less diameter than that of the inlet chamber 59, and carries a stem 55 which through an abutment member 54 and a collar 57 supports a packing cup 52 of rubber or the like. A spring 58 presses the cup 52 against the abutment member 54. The latter and the collar 57 are retained by a nut 56. The valve member 47 is loaded by a spring 50 which is adjustable as in the previous form. The spring chamber communicates with the delivery connection 32 by a passage 55a. The relief connection 18 which opens into an annular space 60 in the housing is formed integrally with a spring-loaded relief valve 64 which is adjusted to open a conduit 67 connecting the pump 34 to the inlet connection 31, to exhaust immediately before the valve 47 opens. The cup 52 acts as the non-return valve and due to the bore in which it operates being greater than the diameter of the valve seat 46, the inlet pressure tends to close the valve 47. The pressure in the accumulator 35 acts on the cup 52 and on the plunger part 51, the resultant force tending to open the valve 47. As the pressure in the chamber 59 drops suddenly due to the opening of the valve 64, before the predetermined high pressure is reached in the accumulator, the valve member 47 opens sharply and remains open until the pressure in the accumulator reaches the predetermined low value. Due to the plunger 51 being less in diameter than the seat 46, any pressure in the space 60 tends to close the valve 47. Where the apparatus is used in conjunction with more than one accumulator, the branch conduits 69, 70, Fig. 3, to each accumulator e.g. 35a, 35b are provided with a non-return valve 71 or 72 each comprising a cylindrical head 77 movable out of a bore 75 against a spring 79, and a tubular stem 76 slidable in the valve outlet. The valve head 77 returns a substantial quantity of liquid to the governor valve 10 when the predetermined high pressure is reached and so maintains the pressure in the delivery connection. The form shown in Fig. 1 is described in connection with a selector valve device having levers to control three slave units. The Provisional Specifications refer to the use of the relief valve in connection with liquid pressure remote control systems for operating parts of aircraft such as the retractable undercarriage, wing flaps, bomb doors, or pontoon jacks.