| 摘要 |
<p>A strip of material (9) which moves upwardly (between plates 27, 29) through a chamber (3) is heated by the discharge of hot gas as a multiplicity of jets on to its surface in a direction normal to that surface, the gases, after striking <PICT:1100892/C6-C7/1> the strip (9) moving laterally of the strip to an exhaust passage extending along one edge of the strip (9). The gases e.g. hydrogen, air an inert gas, or gaseous products of combustion) are circulated by a fan 11 and heated in a chamber 21 by a gas burner 17 (burning, e.g. town gas) or alternatively an electric heater or an indirect heat exchanger. The gases pass from chamber 21, through ducting and downwards into plenum chambers 23, 25 horizontally into ducts 47 formed between baffles 41 and pass through a plurality of circular apertures 31 in plates 27, 29 to impinge on the strip (9). The ducts 47 extend over the height of the chamber (3) through which the strip (9) passes, and is divided vertically into three portions, a central portion in which baffles 41 are vertical, and upper and lower portions in which baffles 41 are slightly inclined to the vertical, and across the strip, to enable even heating across the width of strip (9). Plates (not shown) over the upper and lower portions prevent gases entering the ducts except via the central portion, where the entrance is controlled by a plurality of individually controllable dampers 49. The spent gases may exhaust to atmosphere or be returned to the fan inlet. A second exhaust passage may be provided along the other edge of the strip (9), the gases from which being exhausted to atmosphere, or returned to fan 11, or passed to the inlet of a second fan serving a second heater, in which case each heater may supply either both plenum chambers or its respective plenum chamber. In the case of the spent gases being exhausted to air, they may be used to pre-heat the air entering the fan(s) or to pre-heat the strip (9).</p> |
