| 摘要 |
PROBLEM TO BE SOLVED: To provide a diffusion furnace that suppresses performance degradation associated with long-term usage. SOLUTION: The diffusion furnace includes a cylindrical heat-insulating cylinder 21 and heating wire 22 that is spirally arranged on the inner circumferential surface of the heat-insulating cylinder 21, and the heating wire 22 is fixed at a movable type separator 23B that can be moved in the direction of outside diameter of the heat-insulating cylinder 21. When a control circuit 31 detects the deterioration of the heating wire 22 based on current values, it controls a motor 241 to move the movable type separator in the direction of outside diameter of the heat-insulating cylinder 21. Thus, even when a part of the heating wire 22 hangs down, the heating wire 22 is moved in the direction of outside diameter so as to prevent the heating wire 22 from being disconnected by contact. COPYRIGHT: (C)2011,JPO&INPIT
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