Patent GB-190919802-A (GB)
Title: Improvement in Apparatus for Preventing Smoke in Boiler and other Furnaces.
Inventor: AMES BRADFORD LAWTON
Filed: 1909-08-30
Granted: 1910-05-19
Abstract: 19,802. Ames, B. L. Aug. 30. Air supply, regulating.-In smoke-consuming devices of the kind in which the valves controlling the supply of air and steam above the fire of a steam-boiler furnace are opened automatically by opening the furnace door, means are provided for closing the valves after a predetermined interval of time, consisting of t i m e - controlled mechanism operating the valves through electric or fluid connexions. As shown in Fig. 1, airsupply valves 13 and a steam-supply valve 16 are adapted to be operated by opening the furnace doors 11, 12. The door 11, when opened, engages with a pin 19 on an arm 18, which is connected to the spindle 17 of the valve 16. The spindle 17 is provided with a pinion 191, which ergages a rack 20 connected to links 23 for operating the valves 13. The door 12 likewise operates the valves through the pinion 26 and rack 25, the pinion 26 being mounted upon the shaft 27, which supports at its upper end a stop-plate 28 having projections 29. A spring 30 restores the shaft 27, pinion 26, and rack-bar to their original positions after a predetermined time. To prevent the shaft 27 from being rotated by the spring until after a predetermined time, a locking-piece 56 pivoted at 55 engages with the projections 29 on the stop-plate by means of a sliding pawl 63 held against the stop-plate by a spring. The locking-piece is prevented from lifting by a trigger 61 which engages with a notch 59, Fig. 2. The time-controlled means by which the trigger 61 is moved consists of a clock-work mechanism 320 having a shaft 31 upon which is loosely mounted a notched disk 32 carrying pins 34, 35, the disk being caused to rotate with the shaft 31 by a spring clutch 310. The secondhand shaft 44 of the clock carries a star-wheel 45, which makes contact at intervals with a brush 46 arranged in an electric circuit. The pins 34, 35 on the disk 32 make contact at intervals with brushes 36, 37, the brush 37 being in circuit with the battery 48, having on? terminal grounded at 49, the solenoid 43 and a brush 52, which is normally insulated at 51 from the shaft 27, but, when the furnace door is open, makes contact with the shaft 27 and is thus grounded. The brush 36 is in circuit with the battery 48, the solenoid 65, and the brush 52. Upon opening the furnace door, the current flows from the battery through the clock mechanism to the disk 32 and the brush 37, the solenoid 43 being energized, and a latch 40, engaging with the notches in the disk, being lifted, thus allowing the disk to rotate until one of the pins 34 makes contact with the brush 36. The current then flows from the battery through the clock-mechanism and disk to the solenoid 65, the core of which moves upwards and strikes the trigger 61, releasing the locking-piece 56 and allowing the plate 28 and the shaft 27 to rotate under the action of the spring 30 and close the valves. Fig. 7 shows a fluid-actuated apparatus. A cylinder 70, provided with a piston 71 and a piston-rod 72 adjustable in length, is constantly supplied with water under pressure through a pipe 75 and a valve 76, an exhaust pipe 77 being provided for the escape of the fluid. A valve 78 in the exhaust pipe is controlled by the rack-bar 25, which is moved, when the furnace door is opened, so as to close the valve. Accumulation of water in the cylinder raises the piston and piston-rod, which strikes the trigger 61 and allows the valves admitting air and steam to the furnace to close, as described above.