| 摘要 |
PURPOSE:To maintain the temperature of substrate in the muffle at a constant level regardless of quantity by inserting a temperature control thermocouple set in a tube for shielding the ambient air, in a insulated state, into the muffle from above, and employing coiled lead wires up to the point of the temperature control heater section with an insulating barrier disposed between the lead wires. CONSTITUTION:An insulating tube comprising insulator for electrically insulating a thermocouple 5 is disposed in a metallic tube 8, and is set above substrates 2 in the muffle 1. The thermocouple 5 for controlling temperature of the heater section 4 is positioned near to the substrates 2 in the muffle 1 so as to quickly detect the temperature change in the muffle 1 for temperature control. To cope with the expansion of the muffle 1 while the ambient air firing furnace is heated from the room temperature to 800-900 deg.C, the coiled lead wires 9 of the thermocouple 5 are extendable. The presence of an insulating barrier 10 prevents the short-circuit between the lead wires 9. |
