| 摘要 |
PURPOSE:To make a heat distribution uniform in the longitudinal direction of a tubular furnace by dividing heating elements of plural pieces of bar-shaped heater units longitudinally juxtaposed along the inside wall of the tubular furnace body to plural regions in the longitudinal direction and connecting the same in parallel. CONSTITUTION:Plural pieces of the bar-shaped heater units 14 are juxtaposed in the longitudinal direction of the furnace body 10 of the tubular electric furnace along the inside wall of the furnace body. Each of the above-mentioned heater units 14 is constituted of the coiled electrical heating wires divided to the three regions; the heating wire 21 for the central part and the heating wires 22 for both ends to be packed into an outside pipe 15 of a quartz pipe and a pair of core wires 19 inserted from both ends of the above-mentioned pipe 15 to the divided parts of the electrical heating wires. Both ends of the heating wire 21 for the central part and the inner ends of the heating wires 22 for both ends are respectively connected to the core wires 19. Lead wires 23, 24 are respectively connected to the outer ends of the heating wires 22 for both ends and the core wires 19 so that control voltages can be independently impressed to each of the divided regions. The required electric voltages are thereby impressed to the heating wires 21, 22 connected in parallel by each divided region common to the entire heater unit 14, by which the heating of the electric furnace is made uniform.
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