GB141137A - Improvements in means for controlling combustion in steam generator and like furnaces - Google Patents

Abstract

141,137. Hopwood, J. M. Jan. 9, 1919. Regulating combustion; fuel, feeding; recorders.-Combustion is controlled in steam or other vapour generator furnaces by changes in the pressure and the velocity of the, steam or vapour supplied. The apparatus, as indicated in Fig. 1, comprises two pressure-controlled devices of the servo-motor type, the one 28 controlling the stack damper 58 and the valve 67 of the stoker engine, and the other 50 the air-supply valve 61. As shown in Fig. 3, the controlling-device comprises a pair of diaphragms separated by a ring 5, each diaphragm consisting of a ring 6, separate rings 10, and a central transmitting-member, all arranged between flexible members 7, 8. The flow or dynamic pressure in the steam-pipe C is admitted above the upper diaphragm by pipe 11, and the static pressure to the space between the diaphragms by the pipe 12, while the space below the lower diaphragm is charged to a suitable pressure and then maintained thereat by means of an air-bell 13. The movements of the diaphragm :are transmitted through linkage to a pilot valve controlling the movements of the piston-rod 30 connected to the damper &c. as shown in Fig. 1, such linkage comprising a compensating-connexion between the piston-rod 30 and the pilot valve such that any movement of the piston-rod tends to return the pilot valve to neutral position, whereby the damper 58 and stoker valve 67 receive only incremental movements corresponding to incremental changes of steam pressure and velocity. The device 50, which is generally similar to that just described, is controlled by the pressure in the furnace chamber 62 acting through a pipe 40 and a liquid-sealed bell. In the case of several generators supplying a common steam main, all the stack dampers and stokers are controlled in common, but individual control is provided for each furnace as regards its air-supply valves. A recorder 18 connected to the upper diaphragm serves as a flow-meter and gives an indication of the horse-power supplied.