GB737565A - Improvements in boiler furnaces - Google Patents

Abstract

737,565. Boiler furnaces. SMITH, W. H. March 12, 1953 [March 19, 1952], No. 7128/52. Class 51 (1). A boiler furnace has a gravity feed for fuel, power-operated means to convey clinker out of the firebox and means controlling the operation of these clinker ejecting means in accordance with the boiler output. All the furnace forms to be described hereinafter have a thermostatically controlled blast fan and each clinker ejecting means is started by a time switch operated according to the time the fan has been running. In addition an ordinary clock is provided to start the means after a predetermined time if the fan has not been running and the boiler has been idling. Each firebox is formed as a water jacket. In the form (Fig. 1) a firebox base 2 is reciprocable being driven by a motor 5 through crank and connecting rod 4, 3. Flexible connectors 7, 8 connect the water space of the base with other water spaces of the boiler. When the base is moved forward it carries clinker 13 with it allowing fresh fuel to fall from a hopper 14 on to the base behind the clinker. On the return movement only the base moves the clinker either breaking off due to its overhanging weight or being broken by a guillotine 15 operated in synchronism with the movement of the base. Clinker is collected in the tray 10 whilst the tray 11 collects any dust and ash falling from the firebox. The form shown in Fig. 2, has a fixed base 20 with a tuyere 21 across the full width of the firebox. A wide fuel feed 22 is regulated by a shutter 23. Combustion is assisted by supplementary air directed into the fire from above through a series of jets 27 in a water cooled economizer-cum-deflector 26. Other air is supplied via air jets 29. A variable stroke, variable frequency ram 30 reciprocated through crank and connecting rod 39, 38 by a motor 40 pushes clinker formation forward and away from the area of the tuyere 21 so that it breaks and falls into the tray 33. A clinker breaking guillotine similar to 15 may be provided. In the above forms the fuel fresh to the firebox is interposed between the air blast and the burning fuel. In the form shown in Fig. 3, the clinker is ejected by a reciprocable ram 64 such that fresh fuel is fed immediately in front of the incandescent regions of the firebed and is thereby subjected continuously to flames and air blast, the latter being delivered through the tuyere 60. The aperture 63 opening to the ash pit 68 may be closed by a shutter 67. The ram and shutter operating mechanisms may be so connected that as the ram ejects the shutter opens allowing the clinker to fall into the ash pit 68 but in a preferred form a rotatable shaft 71 carries a crank 72 which by means of a cam roller 73 moves the pivoted lever 74 to withdraw the shutter during one half revolution and moves the pivoted lever 76 to push the ram during the other half revolution; the two are returned' to their "at rest" position by a spring 77. A shutter 70 scrapes the ram on its withdrawal. The combustion gases pass to the flue 78 through the ash pit. In the form shown in Fig. 4, the grate 83 comprises bars hung on an axle 84 and supported by a rear adjustable axle 85. Combustion air is fed to the fuel bed from below the grate by a fan 86. With this arrangement clinker 90 is formed between the grate 83 and the water jacketed bed 82 and is removed by a ram 92 to an ash pan 93. The ram is moved by a rack 94 operated by a pin 89 driven by links 103, 102, 101 from an electric motor 100. An adjustable lost motion device with nuts 104 is interposed between the links 103, 102.