| 摘要 |
PURPOSE:To obtain a work of constant quality by covering the outer periphery of a process tube with an inert gas to prevent the infiltration of air into the atmosphere in the tube at the time of heat-treating the work in the process tube. CONSTITUTION:The work 4 to be treated is placed in the process tube 1, the inside of the tube is evacuated through an exhaust port 2, gaseous HCl, etc., are simultaneously introduced, and the work is heat-treated by a heater 5 and then cleaned, etc. At this time, the whole outer periphery of the process tube 1 is covered with an outer tank 6, a gap 7 for introducing the inert gas such as gaseous N2 is provided between the tube 1 and the tank 6, hence an outflow of the gas in the tube 1 is prevented even when a lid 3 for the tube 1 cannot be completely closed, and further the infiltration of air into the atmosphere in the tube 1 is prevented. By this method, the work 4 of constant quality can be obtained.
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