GB633836A - Improvements in or relating to hot air furnaces - Google Patents

Abstract

633,836. Air-heating furnaces. ABBEY, A. (Miles, J. C.). Oct. 2, 1946, No. 29412. [Classes 64(i) and 64(iii)] In an air-heating furnace comprising a combustion chamber 16, a grate 19, and a smoke chamber formed by walls 37, 38, an air-heating chamber 11 extends from the front to the rear of the furnace on opposite sides of the combustion chamber the air inlet being at the bottom and the air outlet at the top, there being fire-tubes 46, disposed in the air heating chamber each having one end opening into the upper part of the combustion chamber and the other end opening into the smoke chamber, the fire-tubes extending downwardly in the air-heating chamber to substantially the grate level and then upwardly, close to the downward reach to form passageways for the air. The cross-section of the fire tubes is substantially elliptical, and between points 52, 53 on the upward reach, the cross-section is turned through 90 degrees with respect to the remainder of the tube cross-section to form a baffle for deflecting the air to the hottest portion of the tubes. Baffles 60 extend between the points 52, 53 and between one firetube and the next, and comprise corrugated curved plates, (see Fig. 6) a corrugated fin 61 on each baffle extending from the mid-portion thereof to the wall 15 of the combustion chamber. Air blown by fans 31 into the air-heating chamber, is heated by contact with the firetubes and is discharged through funnels 70 at the top of the casing. The air pressure of the blowers is sufficient to swing open the dampers 27 so that air may enter the furnace ashpit through apertures 20 to support combustion. A manually operated damper 41 regulates the flow of combustion gases through the airheating tubes. Specification 605,375 is referred to.