GB777885A - Plug valve - Google Patents

Abstract

777,885. Valves. HEINEN, J. April 18, 1955, No. 11148/55. Class 135. A rotary plug valve is provided with plates D which, when the plug is rotated to the closed position, are moved radially to seal off the flow passage, and the means coupling together the plates and the plug comprises a floating ring 100 which carries the plates around with it and which can be locked to the plug so that it turns with the plug around the axis of the latter. In an embodiment, a plug B with a through passage of rectangular cross-section can be rotated by a stem 31. Held on to the plug by vertical dovetail connections are segmental plates 50 which are provided with horizontal key-like cams 64 supporting passage sealing plates D. The latter are provided with projections 101 engageable in slots in ring 100 which thus carries the plates D around with it as it rotates but allows inward and outward movement of the plates. Locking detent rollers 120 are carried on ring 100 between upstanding projections 127 thereon so that the detents can move inwards to engage in a recess 140 in a drive ring 118 fixed to stem 31 or outwards to engage in a recess 141 in a collar 131 rigid with the valve casing. In turning the valve from the fully open to the closed position, rollers 120 seat in recesses 140 and ride against the inside edge of collar 131 as they are carried round with the stem, ring 100, plug B, and plates D. After a 90 degree rotary movement, the plug will fully close off the flow passage, and rollers 120 will engage in recesses 141 to stop further rotary movement of ring 100 and the plates D. On a slight further movement of the plug, the cams 64 will cause the plates D to move outwards to seal off the flow passage. The plates are covered with rubber 53a. In a modification, a stem 31 with locking detents 120 &c. is provided at both top and bottom of the valve.