GB1199092A - Radiant Heating Tubes for Industrial Furnaces - Google Patents

Abstract

1,199,092. Radiant heating tubes. J. AICHELIN K.G. 16 Aug., 1968 [17 Aug., 1967], No. 39225/68. Heading F4B. A radiant heating tube comprises a flame tube 6<SP>1</SP>, into which a burner 3, supplied with fuel and air through lines 4, 5, respectively, projects, the flame tube including at least in part interfitting arcuate ceramic segments. In the sheathed tube embodiment of Fig. 3, these segments, which are provided with interengaging tongue and groove surfaces, are assembled to form a heat-resistant lining within steel inner tube 14, adjacent assembled arcuate segments being stacked one on another, over the length of tube 14 between supports 11 and 12. Combustion gases from the short flamed burner 3 escape through the open end of tube 14, back through annular passage 15 between inner and outer steel tubes 14, 13, respectively. Projections 70 on the segments promote turbulence and so complete combustion of the gas/air mixture. In a modification (Fig. 5, not shown).the assembled segments themselves form the inner tube which is enclosed by a cage of vertically extending ribs supported against an outer steel tube. The exhaust gases from the inner tube, which escape through apertures in the segments, remote from the burner pass back along the groove-like exhaust paths defined between the inner and outer tubes and the ribs. The assembled segments may also be used to form one limb of a U-tube radiant heater (Fig. 1, not shown) or to form a straight through-flow or sinuous radiant heating tube (not shown). The segments are made of fireclay and/or silicon carbide, and may be permeated with a nickel catalyst to promote complete combustion. The wall thickness and the heat conductivity of the segments may be varied over the length of the radiant tube to promote even radiation along it. Exhaust gases from the tubes may be used to provide a protective atmosphere for the furnace in which they are installed. Coal gas, oil or hydrocarbon gases may be burnt within the tubes.