Patent GB-754440-A (GB)
Title: Conduit gate valve
Inventor: BREDTSCHNEIDER KURT BRUNO
IPC: F16K3/18
Filed: 1954-01-18
Abstract: 754,440. Valves. CRANE CO. Jan. 18, 1954, No. 1512/54. Class 135. In a gate valve comprising a valve assembly 5 including at least two elements with inclined mutual bearing surfaces which on relative vertical movement of the elements cause an expansion movement of the assembly into engagement with the valve seats, the elements are interconnected by one or more springs 33 extending transversely to the direction of movement of the assembly and capable of flexure on relative movement of the elements, the or each spring being anchored to one element and connected to the other element so that on flexure due to the relative movement of the elements the spring moves freely in the other element in the direction of the length of the spring. The valve assembly 5 is mounted in a chamber 2 formed in a casing 41 having opposed seats 8, 9. The springs 33 are mounted in relieved side portions of a central element 15 and in the unstressed condition lie in a straight line and hold the outer elements 6, 7 in non-wedging relation with the central element 15 so that they do not touch the seats 8, 9. On relative movement between the element 15. and the elements 6, 7, the springs 33 are flexed and due to the engagement of the central element 15 with wedge surfaces 41 and 39 or 43 and 44 the outer elements are pressed apart. The valve assembly is suitably ported to co-operate with the seats 8, 9. The spring comprises a number of leaves 33 held between points 31, 32 at the mouth of central recesses 28, 29 in the outer elements 6, 7. The spring leaves 33 pass through transverse side recesses 34 in the central wedge element 15 wherein they are gripped by opposed projections 36. The leaves 33 are prevented from leaving the recesses 34 by side plates 37. The closure member is operated by a stem 23 having a head 22 engaging recesses 19, 21 in the elements 6, 7. The central wedge element 15 has opposed stop fingers 27 adapted to stop further upward movement of the member by engaging the stem bush 24. When this happens the elements 6, 7 continue to rise slightly, the spring leaves 33 are flexed as shown, and the elements 6, 7 are forced outwardly against the seats 8, 9 due to the interaction of the surfaces 41, 39 with those on the lower part of the wedge element 15. When the valve assembly is lowered, the ports in the elements 6, 7 are moved out of alignment with the passages 10, the spring leaves 33 straighten in an intermediate position and then flex downwardly when a stop member 45 engages a projection on the floor of the valve chamber 2. In the intermediate position, the elements 6, 7 are forced away from the seats 8, 9 by spring-loaded guide members 11, 12 such as those shown in U.S.A. Specification 2,504,924. In modifications, the intermediate wedge member is omitted and the wedge surfaces 52, 53, 54, 55 are arranged to coact as shown in Fig. 4, a recess 50 being arranged at the intersection of the surfaces. In Fig. 4, the springs comprise four elastic bolts 57 in recesses 60. The bolts are secured at one end by threaded extensions 59 and at the other end pass loosely through apertures 61 and have nuts 63 and shouldered washers secured thereon. The wedging member 49 carries stop members 64, 65. In another of these modifications the resilient means comprises a series of spring leaves such as 33 clamped by shims at one end to one of the wedging members and enjoying limited pivotal movement at the other end with the other wedging member.