GB335552A - Improvements in and relating to boiler furnaces - Google Patents

Abstract

335,552. Neil, J., and Neil, J. M. May 25, 1929. Urates; firebridges ; furnace fronts; doors. - In a boiler furnace, particularly adapted for burning fine fuel, having a trough grate 1, 2, and a firing door 26 arranged above a cleaning door 27, means are provided for supplying pressure air upwardly through the grate, forwardly over the fire from the front of the furnace, and upwardly from behind the firebridge 6. The air is supplied through a duct 15 which communicates directly with the ashpit 11 and also with pipes 8 extending therethrough, the air delivered by these pipes passing through a chamber 9 in the bridge-supporting structure 7 to a pair of vertical fan-shaped nozzles 19. The apertures 17 through which air enters the pipes 8 are controlled by plugs 16 carried by externally operated rods 18. The doors 26, 27 carry perforated plates 28, 29 spaced from the doors to provide communicating chambers 30, 32 through which air passes upwardly from the ashpit to the delivery apertures 31, 33 in the plates. Some of the air entering the chamber 30 passes into side chambers 34, formed by the front portions 35 of the side grates 1, and from thence, through damper-controlled openings 37, to a space 38 which surrounds the door-frame and is provided with a perforated inner wall 41. The grate comprises a sectional flat bottom 2, supported by depending lugs 12 on the pipes 8, and sectional side portions 1 which rest, at their upper ends, against the wall of the flue 13; the apertures 4 in the grate sections are of Venturi form, as shown in Fig. 2, with the throat portion nearer the upper surface.