GB323219A - Improvements in furnaces burning pulverulent fuels - Google Patents

Abstract

323,219. Bennis, A. W. July 25, 1928. Pulverulent-fuel furnaces.- In a pulverulent-fuel furnace the cross-sectionel area of which gradually increases from the base upwards, cooling air is passed through the hollow passages of a grid or perforated furnace base and merges into a further supply of air with which it passes between adjacent elements of the grid or base to the furnace. In the boiler furnace shown in Fig. 1, pulverulent fuel supplied by a burner 14 is burnt in suspension in a tapered combustion chamber where it meets an upward current of air from a rotary ashremoving grid 18 consisting, as shown in Fig. 4, of a cylindrical drum formed of spaced bars 18 having cooling passages 28 communicating with an air supply conduit 31 and with the interior of the drum to which air is also supplied from a conduit 34 to mix with the cooling air and finally pass between the bars 18 to the furnace. In a modification two drums rotating in opposite directions and spaced apart may be employed. In further modifications the grid may be in the form of a travelling chain grate as described in Specifications 313,551 and 314,236 or as shown in Fig. 9 in the form of a horizontal grate the bars 64 of which are hollow and supplied with cold air from a chamber 66, such air subsequently passing between the bare with preheated air from a chamber 67. In the modification shown in Fig. 8, air from the chamber 50 passes through the bars 53 directly to the furnace or to the hot air chamber 51 and thence between the bars to the furnace. The lower parts of the combustion chamber walls are also provided with grids, through and between which air is supplied from the chambers 58, 59. The position of the burner may be varied. In the modification having two rotary grids at the base the burner may be situated between them to project the fuel upwardly. In all the modifications described the ashes are finally carried away by one or more travelling conveyers.