Glass tube of reed switch used for e.g. technical applications, has inner bore and cross- sectional constriction with relationship applicable between respective cross- sectional constriction and diameter of circumference of inner bore

摘要

The glass tube has an inner bore and a cross-sectional constriction. The relationship applicable between the respective cross-sectional constriction x and the diameter d of the circumference of the inner bore is x greater than or equal to 0.02*d. For the relationship between the respective cross-sectional construction x and the diameter d of the circumference of the inner bore the relationship applicable is: x is greater or equal to 0.1*d. The inner bore has a rectangular cross-section where corners of the rectangular cross-section define the circumference and where the cross-sectional constrictions are formed as convex menisci projecting inwards on opposing tube walls. The glass tube has an inner bore with an inner edge, where the radius of curvature of the respective inner edge is less than or equal to 0.1 mm. The radius of curvature of inner edge is less than or equal to 0.03 mm. The glass tube is a sheath tube for reed switches. The glass tube is produced from a preform by way of a redrawing process. The preform is produced by a casting process. The casting process molten glass is poured or cast into a shaft of a device in the interior of which is located a mandrel, for defining the inner bore. An independent claim is included for a method for the production of a glass tube for encapsulating electrical or magnetic components, where the glass tube is produced from a preform by way of a redrawing process, and a preform for the production of glass tubes.