Improvements in Self-closing Stop Valves

28,882. Bromhead, S. S., [Cruickshank, F. W., and Hagstr÷m, A.]. Dec. 18. Valves closing with rush of fluid.-Relates to a valve attached at 1 to a boiler and adapted to be closed automatically if the steam-pipe 5 bursts. The valve stem 8 is provided with a piston 9 slightly larger than the valve 6, and a piston valve 21 is situated in a cylinder 15 adjacent to the main valve. The cylinder 15 communicates through a port 16 with the hollowed-out part 30 above the main valve-seat, through a port 17 with the space above the piston 9, and through a port 18 with the interior of the boiler. The threaded spindle 12 is normally set so that the steam pressure holds open the valve 6, and the piston valve 21 is set so that it covers the port 17. Should the steam-pipe 5 burst, the suction caused by the rush of fluid draws down the valve 21, thereby uncovering the port 17, whereby steam from the boiler flows to the space above the piston 9 and forces down the valve 6 and closes it. The part 30 guides the flow of the steam in a curved path past the mouth of the port 16 and prevents it from entering the same with its full force.