Patent GB-613919-A (GB)
Title: Burners for solid fuels
IPC: F23G5/20
Filed: 1945-06-08
Abstract: 613,919. Furnaces. FULTON, W. M. June 8, 1945, No. 14599. Convention date, July 27, 1944. [Class 51 (i)] Solid fuel is burned on separate aligned rotary cylindrical grates, the fuel being agitated on the first grate while it is reduced to the condition in which it will burn satisfactory with less agitation, this final combustion being effected on a grate following the first grate. As shown, the reduced ends 30 of grate bars 28 are mounted with radial play in slots in the rings 31, 32 which are driven by ratchet gearing at a higher speed than a ring 39, 40 carrying grate bars 43 also with radial play. Tangential air passages 36 are left between the bars 28 which, at the bottom of their path rest on the inner cylindrical wall 4 of a jacket 7 supplied with boiler water, or, if the furnace is for heating air, with air. The bars 28, at the top of their path, fall because of the radial play, on to the upper wall of an arcuate water jacket 105 connected with the main jacket 7 and protected by a refractory baffle 108. The bars 43 are similarly cooled and protected. The jacket 105 is preferably slightly eccentric relatively to the wall 4 to increase the intervening space as the grate bars pass therethrough. The body of the combustion chamber may be.made by securing together a number of sections, push nipples 16 forming water-tight connections between the sections. At the bottom, the sections are gapped on their opposed faces, to form air inlet passages 20, the width of the gaps, and consequently the quantity of admitted air, decreasing from the charging to the discharging end of the furnace. Air is supplied from a blower 27 through a conduit 26, the blower also supplying through a pipe 102, an air-jet in, and directed parallel to, the feed shoot 54 to prevent ignition of fuel in the shoot. The blower 27 is driven by a motor 56 which is connected also, through a link 65, crank 64, reduction gearing and belting, with a lever 66 fulcrumed on knife-edges 68, 71. The lever 66 is bifurcated at its middle part to receive a lever 74 pivoted to the lever 66 at 75 and connected by rods 76, 77 to crank-arms 80, 81 keyed on shafts 82, 83. Pawl-carrying crank arms 86, 87 are mounted on the shafts 82, 83 the pawls 88, 89 being kept in engagement with ratchet teeth 37 on the rings 31, 32 by springs 90, 91. Shorter crank-arms are mounted on the ends of the shafts 82, 83 to carry pawls to engage finer pitched ratchet teeth 41 on the ring 39, 40, which is thus moved more slowly than the rings 31, 32. The rings are positioned axially by stepped ports 5, 6, 10 of the wall 4, and sealing is effected by resilient packing rings 112, 113 which are collapsed slightly circumferentially before being inserted in bevelled recesses 110, 111, the tendency of the rings to expand exerting a wedging-action of the bevel. Fine ash, which may pass the seals is removed by a screw conveyer driven by a ratchet wheel 125 and a pawl lever 126 driven by a pin 127 projecting from the lever 66. In a modification, the ratchet and pawl gearing for rotating the grate is replaced by rack and pinion gearing, the pinions acting at diametrically opposite points and being driven from a motor through reduction gearing and a cross shaft with a different gearing. The final combustion zone of the furnace may be non-rotary in which case the ash is discharged by the helical edge of the rotary part as described in Specification 613,918.