摘要:
A resistance furnace has a tubular heating element with a vertically-oriented longitudinal axis. The heating element has a shell surface defined by an upper side and a lower side and surrounding a furnace chamber. The heating element is connected to at least two supply terminals by which heating current is introduced at power supply points into the heating element. The supply terminals include a surrounding upper annular collar adjacent the upper side of the shell surface, and also a surrounding lower annular collar adjacent the lower side of the shell surface.
摘要:
In a known method for producing tubes of quartz glass, a hollow cylinder (2) of quartz glass is continuously supplied to a heating zone (1) and is softened therein in regions, and a tube strand (21) is drawn off at a drawing speed from the softened region with formation of a drawing bulb (26), and the tubes to be produced are cut to length in the form of tube strand pieces by separating the tube strand (21) at a desired separation point (T, Vu, Vo) and an internal pressure differing from the external pressure applied to the outer cladding is maintained in the inner bore (4) of the hollow cylinder (2) in that the inner bore (4) of the tube strand is provided with a flow obstacle. Starting therefrom to indicate a simple method which permits the manufacture of particularly large volume quartz glass tubes with utmost precision, while observing narrow tolerances, it is suggested according to the invention that the flow obstacle should be configured as a constriction (28, 29) of the inner bore which is produced by softening and plastic deformation of the tube strand in the area of a deformation zone (Vu, Vo).
摘要:
Known synthetic quartz glass tubes for the production of a preform have an inner bore with a surface layer produced without using tools in the molten state and an inner zone. The aim of the invention is to provide a tube which does not release any OH groups to the surroundings. For this purpose, the surface layer (30) has a thickness of 10 μm and an average OH content of not more than 5 ppm by weight and an average surface roughness Ra of not more than 0.1 μm. The inner zone (34) that starts on the surface layer (30) and terminates 10 μm before the outer wall has an average OH content of not more than 0.2 ppm by weight. A simple and inexpensive method for producing a quartz tube of the above type is to continuously draw a tube strand from a softened quartz glass mass in a vertical drawing process. A scavenging gas is circulated through the inner bore of the tube, said gas having a water content of less than 100 ppb per weight. The front end of the tube strand (19) is closed by a flow obstacle (26) that is permeable the scavenging gas and that reduces the amount of scavenging gas (23) flowing through.
摘要:
The production of an optical component from quartz glass, by elongation of a coaxial arrangement of a core rod and a hollow cylinder of a given length, is known. The arrangement is thus introduced into a heating zone with a vertical orientation, such that the lower end begins to partly soften and the component is drawn downwards from the softened part. The hollow cylinder has an inner passage, provided with a restriction in the region of the lower end thereof, on which the core rod is supported. Several methods are disclosed for formation of the restriction in which the inner passage (55) is mechanically machined to a final dimension and, in one version of the method, the restriction in the inner passage (55) is generated by means of softening the lower end face of the hollow cylinder, swaged against a tool and thus folded inwards with formation of a peripheral bead ring.
摘要:
Known synthetic quartz glass tubes for the production of a preform have an inner bore with a surface layer produced without using tools in the molten state and an inner zone. The aim of the invention is to provide a tube which does not release any OH groups to the surroundings. For this purpose, the surface layer (30) has a thickness of 10 μm and an average OH content of not more than 5 ppm by weight and an average surface roughness Ra of not more than 0.1 μm. The inner zone (34) that starts on the surface layer (30) and terminates 10 μm before the outer wall has an average OH content of not more than 0.2 ppm by weight. A simple and inexpensive method for producing a quartz tube of the above type is to continuously draw a tube strand from a softened quartz glass mass in a vertical drawing process. A scavenging gas is circulated through the inner bore of the tube, said gas having a water content of less than 100 ppb per weight. The front end of the tube strand (19) is closed by a flow obstacle (26) that is permeable the scavenging gas and that reduces the amount of scavenging gas (23) flowing through.
摘要翻译:用于生产预成型件的已知的合成石英玻璃管具有内孔,其具有在不使用处于熔融状态的工具和内部区域的情况下制备的表面层。 本发明的目的是提供一种不会向周围释放任何OH基团的管。 为此,表面层(30)的厚度为10μm,平均OH含量为5重量ppm以下,平均表面粗糙度R a a为0.1μm以下。 在表层(30)之前开始并在外壁具有不大于0.2重量ppm的平均OH含量之前终止10um的内部区域(34)。 用于生产上述类型的石英管的简单和便宜的方法是在垂直拉伸过程中连续地从软化的石英玻璃块抽取管束。 清除气体通过管的内孔循环,所述气体的含水量小于100ppb /重量。 管股(19)的前端由能够吸收清除气体的流动障碍物(26)封闭,并减少流过的清除气体(23)的量。
摘要:
The production of an optical component from quartz glass, by elongation of a coaxial arrangement of a core rod and a hollow cylinder of a given length, is known. The arrangement is thus introduced into a heating zone with a vertical orientation, such that the lower end begins to partly soften and the component is drawn downwards from the softened part. The hollow cylinder has an inner passage, provided with a restriction in the region of the lower end thereof, on which the core rod is supported. Several methods are disclosed for formation of the restriction in which the inner passage (55) is mechanically machined to a final dimension and, in one version of the method, the restriction in the inner passage (55) is generated by means of softening the lower end face of the hollow cylinder, swaged against a tool and thus folded inwards with formation of a peripheral bead ring.
摘要:
In a known method for producing tubes of quartz glass, a hollow cylinder (2) of quartz glass is continuously supplied to a heating zone (1) and is softened therein in regions, and a tube strand (21) is drawn off at a drawing speed from the softened region with formation of a drawing bulb (26), and the tubes to be produced are cut to length in the form of tube strand pieces by separating the tube strand (21) at a desired separation point (T, Vu, Vo) and an internal pressure differing from the external pressure applied to the outer cladding is maintained in the inner bore (4) of the hollow cylinder (2) in that the inner bore (4) of the tube strand is provided with a flow obstacle. Starting therefrom to indicate a simple method which permits the manufacture of particularly large volume quartz glass tubes with utmost precision, while observing narrow tolerances, it is suggested according to the invention that the flow obstacle should be configured as a constriction (28, 29) of the inner bore which is produced by softening and plastic deformation of the tube strand in the area of a deformation zone (Vu, Vo).