Patent GB-345739-A (GB)
Abstract: 345,739. Furnace grates. ASSOCIATED ELECTRICAL INDUSTRIES, Ltd., Bush House, Aldwych, London.-(Assignees of Foresman, R.. A. ; 805, 14th Avenue, Moore, Pennsylvania, U.S.A.) Jan. 23, 1930, No. 2415. Convention date, Feb. 4, 1929. [Class 51 (i).] An underfeed grate section 23 of the multiple retort type is adapted to discharge the portion of the fuel bed in the initial stages of combustion from the rear ends of the retorts and the portion in a more advanced stage of combustion from the rear ends of the tuyere rows on to an overfeed grate section 26 of substantial size and of the undulating type comprising a series of grate members pivotally connected in end-to-end relation and moving both angularly with respect to the fuel surface and bodily in the general direction of the fuel feed. The ash &c. passes to a water-cooled clinker pit 32. The underfeed section 23 comprises alternately arranged retorts 24 and tuyere rows 25 extending in the direction of fuel feed and supported at the lower end by a beam 36 forming part of a wall 37 dividing the space below the grate into a front chamber 38 which supplies air to the tuyeres 25 and a rear chamber 39 supplying air to the overfeed section 26. Air is supplied to the front chamber by a conduit 40 and passes to the rear chamber through a damper-controlled opening 41 in the wall 37. The overfeed grate members each comprise a rectangular frame 60, Fig. 8, provided with opposed transverse ribs 64, 65 which hold a plurality of grate bars 63 having corresponding undercut recesses 66, 67. Gaps are formed in the ribs 64, 65 through which the grate bars are inserted, the last grate bar being held in position by a locking pin. Each grate frame has a pair of lugs 71 extending downwardly from the forward end and pairs of lugs 75, 77 entering downwardly and rearwardly respectively from the rear end. The first grate member 27 is pivoted by its lugs 71 to a rod 73 carried by fixed brackets 74 and is connected to the grate member 28 by a rod 92 while the members 28 .. 31 are pivoted together by their longitudinally extending lugs. The downwardly extending lugs of the grate members 27, 29 are connected by links 115, 117 with the ends of a rocking lever 114 keyed to an oscillating power shaft 113 while the corresponding lugs of the alternate grate members 28, 30 are connected by links 125, 130 with fixed pivots 128, 133. The rear ends of the rear grate members 31 are slidably supported on a row of water-cooled castings 105 carried by the front wall 33 of the ashpit 32. The grate bars 33 have vertical air supply grooves and are spaced apart by projections 107. Mounted loosely on the outer ends of the power shaft 113 are bell cranks 146 oscillated by connecting rods 148 from cranks 145 driven by a motor 141. A rod 149, Fig. 10, is connected by a pin 150 to the arm 151 of the bell crank and carries loosely at its upper end a yoke 153 having abutments 154, 155 adapted to be moved by a collar 160 secured to the rod 149 by a shearing pin 161. A number of shoes 162 are disposed between the collar 160 and the abutments, being held in place by detachable plates 163, and varying degrees of lost motion may be obtained by inserting or removing the shoes. The yoke 153 has lateral arms 156, 157 connected by rods 164 to arms 167 keyed to the power shaft 113. Should the grate members become jammed the shearing pin 161 will fail preventing damage to the parts. Coal is fed from hoppers 46 into the retorts 24 by primary rams 47, and secondary rams 57 feed the coal upwardly into the fuel bed and laterally on to the tuyere rows. Ash hoppers 42, 43 form the lower portion of the air chambers 38, 39 and have valve controlled openings 44, 45. The power shaft 113 may be divided in the centre of the grate so that the two halves may be operated at different speeds and in such a manner that the parts move in opposite directions. The water-cooled castings 105 on the front brick wall 33 of the ashpit comprise a body member 175, Fig. 8, and a cover member 176 and include a basin 181 for collecting water supplied. by a pipe through an opening 177. The water overflows through openings 178 and flows down the smooth wall 33. Air also passes through the openings 178 into the ashpit to complete combustion. Air supply boxes 185 are embedded in the wall 33 and allow additional air from the chamber 39 to pass into the pit 32. Grinder rolls 34 extend through openings 190, Fig. 14, in the walls of the pit and are driven by pawl and ratchet mechanism 193 from a motor 194, the rolls being divided in the centre. Laterally extending structures 200 are provided at each side of the furnace adjacent the openings 190 to provide a water seal. A sluice 204 conducts away the refuse from the lower part 203 of the ashpit. Specification 287,748, [Class 51 (i), Furnace and kilns, Combustion apparatus of], is referred to.