Patent GB-193183-A (GB)
Title: Improvements relating to safety apparatus in connection with flow of fluids through piping
IPC: F04B49/02
Filed: 1921-12-03
Abstract: 193,183. Stokoe, C. L. Dec. 3, 1921. Addition to 138,424. Stop-gear. - An apparatus operated by the flow of fluid in a conduit and adapted on cessation of flow to operate electrical or mechanical gear is actuated by a flap b mounted on a spindle j and pressed towards a deflector a in the fluid conduit by a spiral spring r carried by a carrier s adjustably mounted in a fluid tight case by interengaging projections and recesses. Leakage past the spindle is prevented by a collar k pressed against a leather or rubber packing washer l by a helical spring g mounted in a case d and adjusted by a screw h. The packing may be backed on one or both sides by further washers of anti-friction metal. The spindle i extends into a casing e and is provided with a squared part p to receive a box o secured by a nut o<1> and on which the actuating- lever n for the electrical or mechanical gear is adjustably clamped by a nut q. The casing e is made fluid tight by a cover f which may have an inspection window and on which external fittings may be secured. The hinged flap may be replaced by a dished disc suspended from a lever. In a modification the packing collar is disposed externally of the valve conduit and the spring case h is mounted on a bridge secured to the casing e in which the spring r is adjustably mounted by a stud engaging one of a series of holes. In a further modification the. spindle is loaded by a weighted lever enclosed in a fluidtight case. Fig. 6 shows the invention applied to a pilot valve for controlling the supply of compressed air or steam for actuating other apparatus for example, the quick, shut-off valve fitted to an engine or pump. The valve is mounted in a casing h<1> and is normally held to its seat either by a spring n<1> or by a blade spring k<1> adjusted by a screw l acting on a lever j<1> provided with an adjustable tappet p<1> adapted to be engaged by the actuating-lever n. In a. modified form the lever j<1> is extended beyond the pivot to form a trip-catch mechanism whereby a weight or spring-loaded valve or switch located outside the casing is adapted to be operated. The switch used with this form of apparatus is shown in Fig. 9 and comprises a contact bridge z<1> mounted on a spring-loaded arm x<1> normally held in the raised position by the. trip-catch s<1>. The bridge z<1> can be secured to either side of the arm so that it can be used to bridge contacts a<2>, b<2> or contacts c<2>, d<2> depending on whether it is desired to make or break circuit on cessation of flow. A pointer z indicates the position of the internal mechanism. In an alternative form of switch adapted to be directly actuated by the lever n an insulating-roller on the lever is arranged to engage a hook-shaped hinged or springy member electrically connected to one pole of the circuit so as to move one of two contacts on the moving member into contact with a fixed terminal. The fixed terminal is adapted to be reversed to allow the switch to break instead of make contact when the lever n rises. When used in connection with a lubricating-system the enclosing-casing may be filled with oil from the fluid conduit, and when used in connection with a low-pressure water conduit, the electrical members work in air trapped in the casing. Specification 168,959 is referred to.