Glass tube for technical applications and process for the production thereof

Abstract

The invention relates to glass tubes for technical applications, especially for electrical or magnetic components, such as reed switches for example. According to a first embodiment, the glass tube has an inner bore (23) and at least one cross-sectional constriction (X) whereby the relationship applicable between the respective cross-sectional constriction (X) and the diameter (d) of the circumference of inner bore (23) is: x greater than or equal to 0.02*d, more preferably x greater than or equal to 0.1*d. According to a further embodiment, the glass tube has at least one inner bore with at least one inner edge, wherein the radius of curvature of the respective inner edge is less than or equal to 0.1 mm and preferably less than or equal to 0.03 mm. The glass tube is used as a preform for a subsequent redrawing process. The preform is formed by casting a molten glass into a shaft in the interior of which is located a shaping means for defining the inner bore. In this case a gas cushion prevents direct contact of the molten glass with the inner circumferential wall of the shaft and/or the outer circumferential wall of the shaping means.

Dependencies are inferred from the claim text.