GB567859A - Improvements in or relating to mechanical stokers - Google Patents

Abstract

567,859. Supplying air for combustion. SMYTH, C. R. W. Aug. 30, 1943, No. 14121. [Class 51 (i)] A chain or travelling grate forced draught stoker is provided with means for controlling the air supply to different parts of the upper run of the grate consisting of a rear chamber and an adjacent chamber nearer to the front of the grate, the rear chamber being supplied with air at at a lower pressure than the adjacent chamber, and means for regulating the air supply to different zones of the grate above the rear chamber and for varying the effective lengths of the rear and adjacent chambers. As shown in Fig. 1A, partitions 45, 60 and 42 divide the space beneath the upper run of the grate into chambers 48, 59. Air is supplied to the chambers 48 through a sealed ashpit 40 and is supplied from the chamber 48 to the rear chamber 59 at a lower pressure through sliding plate valves 65, Fig. 3, controlling apertures 64 in the partition 60. The valves 65 are mounted on pins 66 and are moved to and from the apertures 64 in the partition by'rods and levers operated from the side of the stoker frame. Above each of the compartments 48, 59 are arranged a number of V-shaped troughs or compartments 76 open at the top and provided with pivoted dampers 78 for controlling the air supply to different zones of the grate above the chambers 48, 59. In the modification shown in Fig. 4, the chambers 48 and 59<1> are separated by a vertical partition 60<1> and inclined partitions 60<11>, 60<111> each provided with air ports 64<1>, 64<11>, 64<111> controlled by valves 65 pivotally mounted at their lower-edges adjacent the lower edges of the ports in the central partition 60<1>. By adjusting the valves to register with the ports in either of the partitions the effective lengths of the rear and adjacent chambers 59<1>, 48 may be varied. Alternatively the valves may be adjusted so that all ports are open and the rear and adjacent chambers are in communication. The front and rear chambers are also provided with valvecontrolled subsidiary chambers 76 for controlling the air supply to the front and rear zones of the grate. The valves 65 in the partition 60<1>, may be adjusted so as to restrict the ports in the partition walls and reduce the air pressure in the rear chamber. Fig. 6 shows a further modification, the front and rear chambers 48, 59<1> are separated by three partitions 60<1>, 60<11> 60<111> provided with ports controlled by pivoted valves 65<1>, 65<11>, 65<111> and trough-shape chambers divided by partitions 93 and provided with valves 78 control the air supply to the various zones of the grate above the chambers. Secondary air is supplied to the combustion chamber above the front and rear of the grate.