| 摘要 |
PURPOSE:To prevent a discharge from leaking from the outside of a furnace tube by disposing a pair of electrodes at a predetermined interval from both end faces of the tube, and further a pair of insulating sleeves to be superposed with the tube and the electrodes, and providing an outer cylinder through a thermal insulator on the outer peripheries of the sleeves. CONSTITUTION:Electrodes 12a coaxial with a furnace tube 11, having the same outer diameter are provided through the tube 11 and a gap 13 at both ends of the tube 11. Heat resistant insulating sleeves 14 coaxial with them are disposed at both ends of the tube 11 and on the outer peripheries of the electrodes 12a. An outer cylinder 16 is provided through a heat resistant thermal insulator 15 on the outer peripheries of the sleeves 14 and the tube 11. Since the gap 13 is interrupted by the sleeves 14, it can prevent the insulator 15 from entering the tube. Further, a discharge leaked from the outside of the tube 11 from the gap 13 through the insulator 15 can be avoided. Further, since the electrode 12a is disposed through the tube 11 and the gap 13. it can prevent the tube 11 from being locally heated by the discharge to damage. |
