HEATING APPARATUS FOR DRAWING GLASS ROD

摘要

: A heating apparatus for drawing a glass rod having a tapered portion coupled, at its upper end, to a feed bar of an outside diameter smaller than that of the glass rod, includes an apparatus housing into which the glass rod is inserted. A first sealing cover is formed with a bore having such a dimension as to seal a clearance between the glass rod and the bore and is hermetically mounted on an inlet opening of the apparatus housing. A second sealing cover is movably attached to the feed bar and is formed with an aperture having such a dimension as to seal a clearance between the feed bar and the aperture. The second sealing cover has a hollow portion that is formed with a space for accommodating the tapered portion, and is hermetically placed, at its lower end, on the inlet opening. The arrangement enables the apparatus to be more compact than hitherto, and specifically avoids the need for the housing to be as tall as the rod is long.