GB996752A - Improvements in or relating to discharge valves for finely divided solid materials - Google Patents

Abstract

996,752. Pneumatic conveyers. COLLECTRON Ltd., and E. WHALLEY. Feb. 19, 1964 [Feb. 19, 1963; March 26, 1963], Nos. 6661/63 and 11968/63. Heading B8A. In a discharge valve 10, Fig. 1, for solid material, comprising at least one pair of hinged flap valves 13, 14 arranged in series for releasing material in batches between regions at different pressures, means are provided for equalizing the pressure on each side of the flap valves so that they fall freely under gravity when the closing pressure is removed. In the example of Fig. 1, the valves 13, 14 are closed by rollers 27 on arms 25 for engagement with wedge-shaped cams 24 on the rear faces of the valves. The arms 25 are also coupled by chains 32 to coilspring type blow-off valves 29 arranged so that movement of the arms 25 to remove the closing force of the flap valves 13, 14 causes a deflection of the blow-off valves 29 to equalize the pressures. The arms 25 are operated sequentially by cams and links and coil springs are arranged between the linkages for the upper and lower arms 25 so that movement to release the closing force on one flap valve, increases the closing force applied to the other. In a modification, a flap valve 58, Fig. 4, is pivoted on a shaft 61 mounted in slotted holes 63 and is loaded near the pivot by a coil spring 71. The arrangement is such that removal of closing force by roller 64 as it disengages from cam 65 permits the spring 71 to pull the valve 58 away from its seating and equalize the pressures before the valve fully opens. The pivot shaft 61 is also enclosed within a tubular easing 74 (not shown) arranged between the pivot bearings 62 to prevent solid material reaching the slotted holes 63. In a further modification a small cut-out portion 84, Fig. 7, of the flap valve 82 is resiliently attached to the flap valve by a flexible member 87 such as a rubber tube held in compression by a tension rod (not shown). The cut-out portion 84 is coupled by a chain 88 to the actuating arm 89 so that movement to release the closing force deflects the portion 84 to open a small section of the valve seating and equalize the pressures before the whole of the seating is withdrawn.