Upon an increase in speed of the turbine shaft, the sleeve of centrifugal governor 1 moves upward and, through a system of levers, turns levers 2, held together by spring 17, about axis O. This shifts the spool of valve 3 downward and hydraulic fluid, delivered by the pump to the valve, is admitted to the lower end of servomotor 4, moving piston 5 upward. At this, gear rack 18 turns pinion 19 and cam 20, lowering regulating valve member 16. This reduces the supply of steam to the turbine, thereby reducing its speed. Feedback levers 15 and 2, connected to the rod of piston 5 and the stem of the spool of valve 3, return the spool to its central position. Upon a drop in speed of the turbine shaft, the elements of the regulator operate in the reverse direction. Upon normal operation, fluid from the mains passes through valve 7 to the lower end of servomotor 8, holding piston 9 in the upper position. At this, detent 10 holds starting valve member 11 open, admitting steam into the turbine. At the same time, fluid under pressure, passing through valve 6, is delivered to cylinder 12, where it holds piston 13 in the upper position, compressing spring 21. When the speed of the turbine exceeds the permissible value, a safety switching member, mounted on turbine shaft A, actuates levers a and d of automatic valves 6 and 7. Lever d is released and the spring of valve 7 shifts the spool to the left, disconnecting servomotor 8 from the high-pressure fluid mains and connecting it to the drain. Piston 9 moves downward, detent 10 releases valve member 11, shutting off steam supply to the turbine. At the same time, the displacement of lever a shifts the spool of valve 6, which connects cylinder 12 to the drain and piston 13 moves downward. Flange b at the end of the rod of piston 13 pulls link 14 downward, overcoming the resistance of spring 17, which holds levers 2 together. The lower lever shifts the spool of valve 3 downward, raising piston 5 of servomotor 4 and closing regulating valve member 16 of the turbine. Thus, the safety switch provides for simultaneous independent closing of both the starting and regulating valve members of the turbine.
$4233$CHP,Rg$