GB556151A - Improvements in valves - Google Patents

Abstract

556,151. Valves. ADAMSON, R. A. March 17, 1942, No. 3493. [Class 135] A valve device adapted to be opened under manual control and close automatically in the event of failure of conduit pressure is fitted with a supplementary valve actuated during the closing movement of the main valve to prevent pressure reaching the actuating piston when conduit pressure is restored. In the form shown in the Figure a tapered sluice valve member 1 is connected by a screw-threaded spindle 3 and nut 20 with the end wall of a cylinder 19 slidably mounted on a fixed tubular member 18. The cylinder is loaded by weights 30 and is provided with packings 23, 24 engaging the nut and member 18 respectively. The space within the cylinder is connected to the main 2 through pipes 15, 17 fitted with a shuttle lift valve adapted to connect the pipe 17 either to the pipe 15 or a pipe 34 leading to drain. To open the main valve a rod 33 is moved to the left to move the valve so as to admit pressure fluid from the conduit 2 to the cylinder. As the cylinder reaches the end of its stroke a cam bar 32 moves into position to maintain the valve in this position. If the pressure fails the initial movement of the cylinder removes the cam from the valve 16 which then moves under spring load to its other extreme position connecting the cylinder to exhaust and permitting the weight load to close the main valve. In a modification the main valve is connected directly to a piston movable in a fixed cylinder connected to the main and exhaust through a three-way valve. This valve is moved to the position to admit pressure by a pull rod, which is afterwards coupled to the valve spindle by a lever and detachable counling so that as the main valve closes the cylinder is connected to exhaust. A further manually operated valve may be inserted in the pipe-line connecting the cylinder and main.