GB669933A - Valve construction - Google Patents

Abstract

669,933. Valves. GROVE, M. H., and GROVE, J. E., (trading as FLUID CONTROL ENGINEERING CO.). Aug. 16, 1949 [Aug. 28, 1948], No. 21318/49. Class 135. A valve comprises a body having a flow passage, a ported valve member 17, Fig. 4, an annular sealing ring 60 surrounding the passage and slidably urged against the valve, an annular space 68 defined by radially spaced cylindrical surfaces on the body and sealing ring, and opposed shoulder faces on these two members, further sealing means 69 located in the annular space and screwing to prevent leakage between the sealing ring and body, the contacting surface 61 between the sealing ring and valve having a mean effective diameter corresponding to the mean effective diameter of the ring 69, and the latter is urged against one or the other shoulder face by line pressure or by pressure in the space 16 in the body about the sealing ring. The invention is applicable to rotary conical, cylindrical, or spherical valve constructions but is shown applied to a sliding gate valve 17, Fig. 2, wherein the sealing ring and valve contacting surfaces 61 are lapped. The fluid in the flow passage 11 or in the space 16, whichever is at the higher pressure, can flow past machined surfaces 63 or 67 and into the space 68, and the net pressure acting on the sealing ring 60 forces the latter against the closure element 17. Leather washers 71, 72 and a resilient, e.g. synthetic rubber, sealing ring. 69 are placed in the space 68, the ring 69 being slidable in the space according to the direction of the higher fluid pressure. Belleville washers 76 urge the ring 60 against the gate 17. The latter slides in guides 83 which are pressed against the edges of the gate by rubber bands 84. The gate is actuated by a handle 46 which engages in an apertured block 38 pivoted at 37 to brackets 36 upstanding from the valve casing, the plate being connected to the valve stem 21 by pivoted links 42. A spring-pressed ball detent engages depressions 49, 51 in the block 38 to hold the gate in the opened or closed positions. To balance the fluid pressure acting on the stem 21, the lower end of the gate constitutes a cylinder slidable over a piston 53 of the same diameter as the stem, and the space 59 between the piston and cylinder communicates with atmosphere through a passage 58. In a modification in which the gate is screw-actuated, a thrust ring is interposed between the casing and the sealing ring 60, and an annular wire spring of zig-zag form is interposed between the thrust and sealing rings.