Abstract: A process for producing glass tubes includes: applying a glass melt onto an outer surface of a rotating conical mandrel by guiding the glass melt from a feed tank through an outlet; forming a hollow glass melt body on the conical mandrel; drawing the hollow glass melt body from the conical mandrel in a predetermined direction toward a front end for forming a glass tube, the outer surface having a wetting zone where the glass strand first contacts the conical mandrel, a spatial variation of the wetting zone of the applied glass melt being monitored by measuring a horizontal movement of an edge of the glass strand; reducing the spatial variation by adjusting one or more process parameters; cooling the hollow glass melt body; and cutting the cooled glass melt body into glass tubes.

Abstract: A glass tube, such as a glass tube for the production of containers for storage of pharmaceutical compositions, facilitates production of pharmaceutical containers with high quality. The glass tube has a relative cross-sectional area deviation defined as QF max - QF min 1.5 ? ? m . QF max - QF min 1.5 ? ? m is less than k*x+t. QFmax is the highest cross-sectional area and QFmin is the lowest cross-sectional area of at least two cross-sections of the glass tube, the cross-sections being spaced apart from each other along a length of the glass tube, and k is 0.0023 m?1, t is less than 0.15 mm2/m and x is QF max + QF min 2 .

Abstract: An apparatus for forming glass tubes is provided. The apparatus includes a Danner-pipe, a heating device, and a heating chamber having the Danner-pipe and the heating device arranged therein. The Danner-pipe is inclined with respect to a horizontal plane by a Danner-angle. The heating device is inclined with respect to the horizontal plane by a heating-angle. The Danner-angle and/or the heating angle are in a range of 1° to 45°.

Abstract: The invention relates to glass articles, such as for example glass tubes or flat glasses, where the material at the surface by a targeted process control has gradient material properties which in turn result in a compressive prestress of the surface. The invention also relates to a method for the production of the glass articles as well as their use.

Abstract: An apparatus for forming glass tubes is provided. The apparatus includes a Danner-pipe, a heating device, and a heating chamber having the Danner-pipe and the heating device arranged therein. The Danner-pipe is inclined with respect to a horizontal plane by a Danner-angle. The heating device is inclined with respect to the horizontal plane by a heating-angle. The Danner-angle and/or the heating angle are in a range of 1° to 45°.

Abstract: A glass tube, such as a glass tube for the production of containers for storage of pharmaceutical compositions, facilitates production of pharmaceutical containers with high quality. The glass tube has a relative cross-sectional area deviation defined as QF max - QF min 1.5 ? ? m . QF max - QF min 1.5 ? ? m is less than k*x+t. QFmax is the highest cross-sectional area and QFmin is the lowest cross-sectional area of at least two cross-sections of the glass tube, the cross-sections being spaced apart from each other along a length of the glass tube, and k is 0.0023 m?1, t is less than 0.15 mm2/m and x is QF max + QF min 2 .

Abstract: The invention relates to glass articles, such as for example glass tubes or flat glasses, where the material at the surface by a targeted process control has gradient material properties which in turn result in a compressive prestress of the surface. The invention also relates to a method for the production of the glass articles as well as their use.

Abstract: The invention relates to a method and a device for homogenizing a glass melt using at least one stirring means which is respectively arranged in a stirring vessel having an inlet (4) and an outlet (5), the respective stirring means having a plurality of stirrer blades (11, 20, 21) arranged spaced apart from one another along a common stirrer shaft (10). According to the invention, the stirring means and/or the device is configured in such a way that a net conveying effect of the stirring means overall from the inlet to the outlet is substantially imperceptible. The conveying effect of the stirring means overall from the inlet (4) to the outlet (5) is caused by the positioning of the stirring blades (11, 20, 21), by the geometric shape thereof and/or by the angular position of the stirring blades in the circumferential direction of the stirrer shaft (10).