Abstract: A method for the sealing of glass tubes in a hot softened state is provided. The method includes softening the glass at a severing zone adjacent to an end portion of the glass tube and rotating the glass tube about its longitudinal axis while being heated until a hot softened state is reached in which the end portion is severed off. The hot softened end portion of the glass tube can be pulled-off from the severing zone by a pulling-off device in such a way that the glass tube is simultaneously heat sealed at the severing zone during the severing process.

Abstract: A method for the sealing of glass tubes in a hot softened state is provided. The method includes softening the glass at a severing zone adjacent to an end portion of the glass tube and rotating the glass tube about its longitudinal axis while being heated until a hot softened state is reached in which the end portion is severed off. The hot softened end portion of the glass tube can be pulled-off from the severing zone by a pulling-off device in such a way that the glass tube is simultaneously heat sealed at the severing zone during the severing process.

Abstract: The glass tube assembly has an outer glass tube provided with a tapered section and an inner glass tube or rod, which is arranged inside of the outer glass tube and which has a spiral section. The tapered section is formed by one or more projections on the inner surface of the outer glass tube. Each projection extends in a longitudinal direction of the outer glass tube and does not extend around its entire circumference. The internal width of the tapered section is smaller than the outside diameter of the spiral section of the inner glass tube or rod, so that the inner glass tube or rod is reliably prevented from slipping or rotating out of the outer glass tube by its spiral section. A method of making the glass tube assembly is also described.

Abstract: A method for fixing the location of a glass rod spiral (5) in a glass tube (2) for applications for the process treatment of a gas flow, wherein the glass rod spiral comprises a spiral-shaped glass tube or glass rod section (5) with a specified outside diameter (W), in which method the glass tube (2) is provided on its internal surface with at least one projection (3) not extending around its full circumference, so that a tapered section of glass tube with a specified internal width (w) is formed to be smaller than the specified outside diameter (W) of the glass tube or glass rod spiral. The projection extends in the longitudinal direction of the glass tube and has a length that is greater than the pitch of the spiral glass tube or glass rod section (5).