| 摘要 |
PROBLEM TO BE SOLVED: To provide a glass tube having small eccentricity, uniform thickness, and excellent characteristics. SOLUTION: The glass tube is manufactured by expanding the diameter of the hole in a tubular glass material by inserting a diameter-expanding member through the hole in the glass material while heating the glass material to a temperature higher than the softening temperature. The tubular glass material may be a product purchased from others or a self-made product. In this method, it is preferable that the diameter of the hole in the glass material is expanded while supporting the diameter expanding member at least at its rear end, or the diameter of the hole in the glass material is expanded while supporting the diameter expanding member at its both ends. The apparatus for manufacturing the glass tube has a heating member for heating the tubular glass material from its periphery, a diameter expanding member capable of being inserted through the glass material, a supporting member for supporting both ends of the diameter expanding member, and a means for relatively moving the diameter expanding member and the glass material so that the the diameter expanding member is inserted through the hole in the glass material. COPYRIGHT: (C)2004,JPO
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