GB534610A - Improvements relating to valves - Google Patents

Abstract

534,610. Valves. SEAMARK, L. M. C. May 23, 1939, Nos. 15352/39, 29519/39, 1886/40 and 4580/40. [Class 135] A rotary plug valve has the plug provided with a channel of closed figure shape and of an open channel shape in transverse cross-sections enclosing an area on the contact surface of the plug that expands, in the closed position of the cock, beyond the perimeter of the closed passage-way in the valve body. A packing housed in this channel is pressed into contact with the contact face of the valve body by conduit pressure reaching the packing through the clearance between the contact faces of the plug and casing. In the form shown in Figs. 1 and 3, the packing comprises an elastic ring f of circular cross-section made of rubber or fabric or fibre incorporated with rubber or synthetic rubber, and a facing ring g of pressed leather, copper, steel or other moderately soft metal notched at g<SP>2</SP> along its inner periphery The rings are housed in a substantially rectangular groove having an inclined bottom face os that as the ring f is forced outwardly by the fluid pressure the facing ring is pressed against the valve seat. The ring f may have outwardly projecting lugs to support the facing ring. The ring f also may be held in place by metal strips recessed into the plug and ring. In the form shown in Fig. 11 the facing strip is supported by a ring f substantially filling the groove and provided with a recess f<SP>3</SP> adapted to receive fluid pressure through a clearance p. In the form shown in Fig. 10 the facing ring is dispensed with, the elastic ring having an internal recess g<SP>3</SP> and a lip g adapted to make a fluid-tight joint with one of the side walls of a square-section groove. The plug Fig. 1 has circumferential grooves at the top and bottom of the plug fitted with packing similar to the packing f, g to prevent fluid passing to the ends of the plug in the open position of the cock. The plug turns on inclined roller bearing c held in place by detachable cover plates d, d<SP>1</SP>, the plate d being fitted with a packing d<SP>2</SP> and the plate d<SP>1</SP> with a drawn aperture d<SP>3</SP>. In the form shown in Fig. 4 a second diametrically opposed packed area is provided and balancing areas surrounded by similar packing are connected by cross passages i, j to the opposed packed areas.