GB851288A - Improvements in or relating to fluid-flow controlling gate valves - Google Patents

Abstract

851,288. Valves. HAMER, L. S. Aug. 21, 1958 [Sept. 20, 1957], No. 26946/58. Class 135. The body A, Fig. 1, of a gate valve is tubular defining a flow passage 11, and extending intermediately therefrom is a chamber 13 open to the passage 11 and closed by a bonnet 32. The body A, which is flanged to pipes P, incorporates annular downstream and upstream projections 20, 21 having opposed faces 22, 23 which are in planes normal and inclined, respectively, to the passage 11; the projection 20 has a number of circumferentially spaced notches 24. The discshaped gate B has one vertical annular side 36 that co-operates with face 22 and an inclined annular end 38 co-operating with face 23, the latter carrying sealing means E in an annular recess 40, Fig. 3. The sealing means E consists of an annular " T " sectioned ring of resilient material such as polytrifluorochloroethylene, a part of which projects beyond the gate, the ring being held in place by an annular locking ring 42 having a flange 53 and a lip 54, the latter overlying part of the sealing ring; the outer extremity of the flange 53 and/or lip 54 form a sealing surface 55 flush with gates. The stem D, Fig. 1, which is connected to the gate by a recessed lug is sealed where it projects from the bonnet 32 by a packing 65 in the bore 66 of a removable tubular extension 67 of the bonnet, the packing being engaged by a follower 68 secured by bolts 70. A further seal comprises a ring 71 in a recess 72 in the bonnet 32, the upper end of the ring 71 being engaged by the extension 67 which is attached to the bonnet 32 by a flange coupling. Upon rotating a hand wheel G and hence a nut 75 carried by a frame 78 upstanding from the extension 67 the threaded stem D is moved vertically to open and close the gate. When the valve is closed any fluid trapped in the chamber 13 can expand and flow into the passage 11 downstream of the gate via notches 24.