| 摘要 |
PURPOSE:To prevent impurities in a furnace from entering a glass tube for cladding by sealing one end of the tube before putting a glass rod into the tube from the other end. CONSTITUTION:A glass tube 1 with one sealed end for cladding is supported with a holding arm 25 connected to a movable support section 23 which is freely movable in the vertical direction. A previously manufactured preform rod 21 is coaxially fixed in the tube 1 in the clean and dry inert gaseous atmosphere of the tube 1 with a holding arm 22 connected to other movable support section 24. By rotating movable screws 26, 27, the support sections 23, 24 are lowered simultaneously and perpendicularly to feed the tube 1 and the rod 21 into a heating furnace 28, and the tube 1 and the rod 21 are melted by heating and unitedly spun at a prescribed drawing speed. |
