GB837057A - Fluid control gate valve - Google Patents

Abstract

837,057. Valves. YOUNG, W. G. Jan. 13, 1958, No. 1143/58. Class 135. In a gate valve comprising a pair of closures 30, Fig. 3, and an interposed wedge 24, the latter is provided with a spring 35 acting through a key 33 to urge the closures in a direction opposite to that of the wedge when it is withdrawn, until the closures have moved laterally out of contact with the inner ends of sleeves 17, Fig. 1, in the flow passage 11. Each sleeve 17 includes a flange 19, Fig. 2, and a recess 21, Fig. 1, formed between shoulders 22, 23 whilst guides 25, Fig. 2, bolted to the wedge 24 slide on flanges 19; the closures 30, which are slidable in the guides, each embody a slot 32, Fig. 3, that is engaged by one end of the key 33 disposed in a recess 34 in the wedge 24. Each closure incorporates an arcuate shoulder 37. To close the valve the wedge 24 and closures 30 are moved downwardly by the threaded stem 14, Fig. 1, until the shoulders 37, 22 engage to hold the closures whilst the wedge completes its movement, which latter causes lateral motion of the closures into contact with the sleeves 17, the shoulders 37 being urged into the recess 21. To open the valve the wedge is lifted alone, since the closures are held by shoulders 37, until it has risen sufficiently to enable the shoulders 37 to move laterally and clear the recess 21; elevation of the wedge relative to the closures continues until the key 33 is at the bottom of the recess 34 whereupon all these parts rise as a unit without rubbing the ends of the sleeves 17. Lugs 30a, Fig. 3, on each closure strike the base of the valve bonnet to force the closures downwardly should foreign matter prevent the key 33 from reaching the bottom of the recess. In a modification, the shoulders 37 and recesses 21 are inclined inwardly so that lateral movement of the closures is accompanied by a slight vertical motion to produce a wiping action of the closures over the sleeve ends. In another modification, the guides are extended and support a hollow cylinder, which, when the valve is opened, is disposed between the sleeves to form a continuous passage through the valve and prevent erosion of the sleeve ends.