GB104732A - Improvements in and relating to Valve Mechanism. - Google Patents

Abstract

104,732. British Thomson-Houston Co., and Halliwell, R. F. March 15, 1916. Regulating.-Relates to valve mechanism particularly for mixed-pressure turbines comprising a single valve for the lowpressure supply adapted to act as a governing- valve and also as a handoperated stop valve, an emergency valve, and an automatic shut-off valve. The valve 1, Fig. 1, admitting low - pressure steam from an accumulator &c. to the turbine conduit 3, is connected to a rocking lever 5 actuated at one end by a piston 13 subjected below by means of an aperture 14 to the steam pressure at the inlet 2, and at the other end by a hand-operated screwed rod 8 so that the valve may be utilized as a manually-operated stop valve. When a handlever 11 is operated to release a trigger, a spring 10 forces down the rod 8, and the valve acts as a manually-released emergency valve. A cam shaft 23, carrying cams for operating the high-pressure valves in the usual manner, is adapted to actuate through the fluid-relay device shown, or by mechanical connexions, a stem 17 for engaging the valve cross-head 4. When closing down, the high-pressure valves close before the low-pressure controlling-gear closes the low-pressure valve. When running the turbine in parallel with other sets, the governor and the main controlling-piston operating the cam shaft are connected as shown, for example, in Specification 20326/11. In a modification, Fig. 2, the stem 17 is connected to one end of the lever 5, and the pressure-responsive device 13 operates the valve 1 through the fluidrelay device 16. The arrangement is such that, if the steam pressure at the inlet is less than atmospheric pressure, the bell-crank lever 22 is unable to move the pilot valve 18 sufficiently to open the valve 1.