GB678565A - Improvements in or relating to stokers of the stepped reciprocating firebar type - Google Patents

Abstract

678,565. Furnace grates. MARTIN, J. J. Sept. 21, 1949 [Oct. 1, 1948], No. 24216/49. Class 51 (i). In a stoker of the stepped reciprocating firebar type protuberances in the form of right prisms or truncated oblique prisms are provided on the upper longitudinal surface at the head and transversely of all or some of the moving firebars, said protuberances being arranged in such a manner that, when the firebars are in their operative positions, one lateral face of each protuberance is approximately vertically disposed, or is inclined so that the top edge of said face overhangs the junction of said face with the top surface of the firebar, a plurality of such faces acting substantially on every return stroke of the pertaining firebar or when the distance between the top ends of adjacent firebars decreases due to relative movement therebetween. The invention is shown applied to the firebars 1 of an " advancing stoker, Fig. 1, having a main stoking action towards the clinker discharging end of the grate and to an " inverse " or "backward pushing" stoker, Fig. 2, in which the main stoking action is towards the feed end of the grate, the protuberances being shown applied to firebars 1 having pusher surfaces 5 partly at right angles to the longitudinal axis of the bars, and partly bevelled, Fig. 5, or having pusher surfaces 5 wholly at right angles to the longitudinal axis of the bars, Fig. 7. The pusher surfaces may protrude or be bevelled off, Fig. 9 (not shown). In the embodiment shown in Fig. 1 in which the distribution of protuberances is such that they increase in number from the middle of the stoker to the head thereof, the other end of the grate having no protuberances, Fig. 2 (not shown), the main action of the latter is, on the return stroke, to convey small incandescent fuel particles backwards, improving ignition in the fuel bed. In the embodiment shown in Fig. 3, the protuberances increase in number from the middle of the stoker to the rearward end and have their vertically disposed or steeply inclined faces directed towards the discharge end of the stoker. With this construction there is a return movement of small incandescent fuel on the conveying action of the firebars, but the main action, on the return stroke of the firebars, is to move large pieces of clinker towards the discharge end of the stoker. In either embodiment, by giving alternate steps of the stoker opposite movements or by keeping alternate steps stationary, a crushing of coke or clinker agglomeratives is obtained between the protuberances on the bars of one step and the pusher heads of the bars on the alternate step.