| 摘要 |
A glass tube (10) with an inner thread (16) in its end section (12) can be screwed to a second glass tube (20) with an outer thread (22), together with a pressure-tight annular seal (26). A process for producing such a glass tube is also disclosed, as well as a device that is particularly suitable for implementing this process. At a distance from the thread (16) a radially projecting annular bearing surface (32) is arranged on the inner surface of the glass tube (10), adjacent to a thicker walled section (18) of the glass tube (10) that has the same inner diameter (24) as the bearing surface (32), whereas the outer diameter (34) of the glass tube (10) is essentially constant. The inner thread (16) and the thick-walled section (18) are formed in a single operation inside the glass tube (10) by plastic deformation. The deformation is essentially effected by uniformly pressing the heated glass tube (10) on a mandrel-shaped moulding body (130) by means of several shaping rollers (86, 96, 98, 100).
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