| 摘要 |
A heating apparatus (K1) for drawing a glass rod (A) having a tapered portion (A') coupled, at its upper end, with a feed bar (8) of an outside diameter smaller than that of the glass rod (A), including an apparatus housing (1) into which the glass rod (A) is inserted, a first sealing cover (7) which is formed with a bore having such a dimension as to seal a clearance between the glass rod (A) and the bore and is hermetically mounted on an inlet opening (2) of the apparatus housing (1) and a second sealing cover (9) which is movably attached to the feed bar (8) and is formed with an aperture having such a dimension as to seal a clearance between the feed bar (8) and the aperture. The second sealing cover (9) has a hollow portion (9a) which is formed with a space for accommodating the tapered portion (A') and is hermetically placed, at its lower end (9b), on the inlet opening (2). |
