GB597965A - Improvement in steam or hot water boilers provided with a furnace - Google Patents

Abstract

597,965. Boiler furnaces. SWENDSEN, D. L. Aug. 25, 1945, No, 21863. [Class 51 (i)] The furnace for a steam or hot water boiler is subdivided by a grate into a lower combustion room, into which combustion air is introduced under pressure below the grate by means of a fan, the said combustion room being connected with the heating surface room proper of the boiler, and into an upper fuel magazine for downdraught combustion of wood and other fuel; a branch pipe proceeding from the pressure side of the fan and entering the upper part of the fuel magazine, whereby said part will be set under pressure and uhburnt gases are prevented from collecting in the fuel magazine while the combustion air will become preheated when flowing downwards. The furnace comprises an upper combustion chamber or fuel magazine 2, with a refilling shutter 4, separated from a lower combustion chamber 3 by a hollow grate 1, the walls of both combustion chambers being provided with a water jacket 5 communicating with the water chamber of a heating surface room 6. Water circulates from the chamber 6, up through a lower grate 13 in the lower chamber 3, up the fore-wall of the furnace and through the grate 1. A fan 7 mounted in the fore-wall supplies pressure air for combustion through pipes 8, 9 and out through slit-shaped inlets 11, 12, whose area is adjustable by flexible bars 29 bolted to external plates 32, into the middle and upper parts respectively of the upper chamber 2. The fan also supplies air through a pipe 10, up through the grate 13 to mix with downcoming combustion gases from the chamber 2. The air supply through each pipe is controlled by weighted dampers 14, 19, 24 respectively which move between stops in such a way that when the fan is stopped the position of the dampers is automatically altered. The dampers are adjusted in different positions according as whether the combustion is to take place in the chamber 2 or the chamber 3.