GB265398A - Improvements in and relating to governing mechanism for prime movers - Google Patents

Abstract

265,398. British Thomson-Houston Co., Ltd., (General Electric Co.). Feb. 26, 1926. Fluid governors; centrifugal governors. - A governor controlling a pilot valve which in turn controls a fluid operated motor has its setting adjusted by two members in threaded engagement one of which is frictionally held from turning whilst the other is rotated by a synchronizing motor, stops on the stationary member being engaged by a stop on the rotating member at either end of the travel so that thereafter the members rotate together. The arrangement as applied to a valve gear of the type described in Specification 229,325. The admission end 5 of a turbine is controlled by a valve such as is described in Specification 229,321, [Class 135, Valves &c.], and operated by a cam shaft 7. A pinion 11 on the cam shaft is in mesh with a rack 12 connected by a rod 13 with a spring- loaded piston 14 working in a casing 15. On the turbine shaft 8 is a worm 18 meshing with a worm wheel 19 on a vertical shaft 20 which drives an oil pump 22 in a tank 9. The oil from the tank is maintained at a definite pressure in a pipe 29 which is in communication with the cylinder 15 beneath the piston 14, as well as in a bye-pass 30 which conducts the oil back to the tank through ports 34, Fig. 2, and the inside of a pilot valve sleeve 73. The extent to which the ports are opened is controlled by a governor 85, which on an increase of speed lowers a sleeve 73 and opens the ports further. A decrease of pressure in the pipe 29 occurs, and the spring loaded piston 14 descends to close the valve 6 to decrease the supply of fluid to the turbine. Hunting of the valve mechanism is prevented by the closing movement of the cam shaft 7 operating a cam 66 which permits a linkage 58-61 to move to the left under the action of a spring 65. A bell crank lever 57 moves a sleeve. 50 and in turn a bushing 33, surrounding the valve sleeve 73 so as to close the ports somewhat. With decrease in the supply of fluid the turbine returns to normal speed. Decrease in the turbine speed causes operation to take. place in the opposite direction. The adjustment of the governor setting for different speeds is effected by changing the setting of the bushing 33 relatively to the valve sleeve 73, which is effected by means of a reversing synchronizing motor 71 controlled by the usual switch. The motor through the worm gear 43 turns a sleeve 44 either up or down and with the sleeve moves a keyed head 35 rigidly connected to the bushing 33. The head 35 screws on a frictionally held stud 38 which allows the head to work between upper and lower limits established by stops 39, 40 which are engaged at top and bottom by stops 41, 41a. When either pair of stops comes into engagement the vertical movement of the head 35 is arrested and if further operation of the motor takes place the stud turns with the head 35 and bushing 33 the friction hold of the stud slipping.