GB133400A - - Google Patents

Abstract

133,400. British Thomson - Houston Co., (General Electric Co.). Sept. 9, 1918. Regulating and controlling.- A pulsation-preventing valve mechanism is combined with a constant-volume regulator of known type. The pivoted beam 13 and sliding weight 17 of the constant-volume regulator are connected to the usual float 18 in the inlet 7 of the compressor 6, which is driven by the turbine 5. Regulation of the turbine speed by the constantvolume regulator is obtained through a lever 12 actuating the pilot valve 11 of a fluid-actuated motor 10, which controls a valve in the pressure-fluid inlet 9 of the turbine. The pulsation-preventing gear comprises a lever pivoted on a fixed arm 16 and connected at one end by a link 47 to a pressureresponsive device connected by a pipe 46 to the compressor delivery 8. A shaft 14, around which the lever 15 can turn, is rigidly connected to the beam 13. The lever 15 is connected to the bypass valve 32 by a link 43, a lever 42, a shaft 41, a sliding plate 36 containing a cam-groove, a rod 34, and an arm 33. The pivot point B of the beam 13 in the lever 15 is lowered either by an increase in pressure in the delivery 8 raising the link 47, or by a decrease in the volume lowering the float 18. When this happens, the link 43 is lowered and consequently the cam-plate 36 is moved. The cam-slot in the plate 36 has two straight portions and a curved portion. When the pin of the rod 34 is in a straight portion, the by-pass valve is not affected; but when the pin is in the curved portion, a movement of the plate 36 operates the by-pass valve in the correct direction to prevent pulsations. Stops 49, 50 limit the movements of the bell-crank lever 23 and correspond to maximum and minimum speeds at which it is desired to run the machine. If, for instance, the float rises to an extent corresponding with the maximum desired speed, the bellcrank lever is moved against the stop 49 and prevents further operation of the steam-regulating mechanism 9 by the volume governor. The speed governor 30 then takes control. Even in this state of affairs, the pulsation-preventing mechanism remains under the control of the force on the float 18 and the discharge pressure, because the pivot point B can move about the pivot of the lever 15 independently of the fixing or otherwise of the bell-crank lever 23. The pulsation-preventing mechanism may thus be brought into operation under all conditions.