| 摘要 |
PURPOSE:To obtain an electric furnace for Bridgman process having a sufficiently long linear inclining zone of temp. by providing another auxiliary heater overlapping a heater at the high temp. side of the electric furnace having a linear inclining zone of temp. at an end of the heater nearer the center of the electric furnace. CONSTITUTION:A high temp. side heater 1 and a low temp. side heater 1' are both formed by winding each nichrome wire having ca. 0.8mm dial. around a quartz core tube 2 having ca. 30mm outside dia. several tens time number of turn in a single layer with ca. 2mm distance and separating several cm from each other. An auxiliary heater 3 is provided by winding a same kind of nichrome wire as the heater 1 with several numbers of turn overlapping the heater 1 and being insulated from the heater 1 at an end nearer the center of the electric furnace 8 of the heater 1. The temp. distribution 4 of the heater 3 alone is represented by an alternate long and short dash line in the drawing, but the temp. distribution curve 5 of the electric furnace when the heater 1 and 1' and the auxiliary heater 3 are actuated simultaneously is represented by a two-dot chain line in the drawing. As clearly recognized by the drawing, the linear inclining zone of temp. 7 is made longer than the same 7' of conventional process.
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