Abstract: A quartz glass tube, produced by mechanically processing a natural/synthetic quartz glass mother material, having 50-300 mm.phi. in outer diameter, from. 1 to 7 in outer to inner diameter ratio, 10 mm or more in thickness and 2% or less in thickness error; a large-scale quartz glass preform integrally combining the large-sized quartz glass tube with a core glass rod for an optical fiber using a rod-in-tube technique; and a method for manufacturing a large-scale quartz glass preform performing the mechanical processing with a high precision machine, i.e., integrating a core rod for an optical fiber under a rod in process with a quartz glass tube, a tube diameter of which is controlled by heating, hot drawing or hot drawing with pressure by using a tool-free drawing method.

Abstract: A method for fabricating a large-sized primary treated quartz glass tube by perforating a cylindrical quartz glass mother material by a hot carbon drill press-in-process followed by etching and washing. The large-sized primary treated quartz glass tube is converted to a large-sized quartz glass preform by combining it with a core glass rod for an optical fiber. Another embodiment is a method for fabricating a large-sized quartz glass tube by heating, hot drawing or hot drawing under pressure using a tool-free drawing method under control of an inside pressure of the large-sized primary treated quartz glass tube at a temperature ranging from 1600.degree. C. to 3000.degree. C. to satisfy a specific equation.

Abstract: Starting from a process for producing a rod-like preform, in particular for optical fibers, in which a tubular blank whose refractive index changes, viewed in the radial direction is fed to a heating zone, is softened there, and in the softened state is shaped to give the preform, a method is described for producing preforms which are hyperpure and low in defects, in which the blank used is one whose refractive index decreases, viewed in the radial direction, from the outside inwards, starting from at least one interface which is at a sufficient distance from the outer surface of the blank, of which that part which has been softened in the heating zone is introverted apart from an outer skin, and by which the preform is formed in the longitudinal axis of the tubular blank, counter to the direction in which the latter is fed to the heating zone, and in which the remaining outer skin is drawn off as a rod in the feed direction of the blank.

Abstract: A process for producing electric stacked capacitors including forming a folded track of capacitor materials which is only a fraction of the thickness of the final capacitor, cutting the folded track into segments equalling the length of the capacitor, stacking the segments on a conveyor belt, hardening the stack, providing external contacts and encasing the capacitor. The process may include placing the folded track on their folded edges and applying pressure between a pair of clamps which have recesses to allow the subsequent forming of the contact regions by a metal spraying process.

Abstract: Apparatus is disclosed for the production of an electric stack or layer capacitor of metallized synthetic material films. The capacitor is produced by bending or folding a film by means of a set of folding wheels which are spaced double the folding width at the film inflow and are spaced as close as possible to one another at the film outflow. The invention is advantageously utilized for the production of layer capacitors.

Abstract: A method and apparatus is disclosed for the production of an electric stack or layer capacitor of metallized synthetic material films. The capacitor is produced by bending or folding a film by means of a set of folding wheels which are spaced double the folding width at the film inflow and are spaced as close as possible to one another at the film outflow. The invention is advantageously utilized for the production of layer capacitors.