The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 15, 1992
Filed:
May. 17, 1991
Helmut Leber, Hanau, DE;
Klaus Reimann, Rodenbach, DE;
Heraeus Quarzglas GmbH, Hanau, DE;
Abstract
A process is known for the tool-free reshaping of a tubular hollow body of amorphous, especially vitreous material to a rod by pressure constriction wherein a pressure depression below atmospheric pressure is sustained in the tubular part by continual evacuation during the constriction, while the hollow body is continually fed horizontally, at a given speed of rotation, to a heating zone, and there its viscosity is so lowered that, as a result of the pressure difference between the absolute value of pressure below atmospheric pressure in the hollow body and the external pressure acting on the hollow body, the hollow body becomes constricted to form a rod in the closing zone and the rod is continually pulled from the closing zone at a given rotatory speed; in order by such a process to produce homogeneous, rod-shaped bodies from hollow bodies in a single procedure and at reasonable cost, the outside dimensions and inside dimensions of the hollow body, the viscosity of the vitreous material in the closing zone, the pressure difference between the absolute value of pressure below atmospheric pressure in the hollow body and the external pressure, the level of the pressure constriction, the rate of withdrawal of the rod and the rate of feed of the hollow body, as well as the rotatory speeds of the rod and hollow body, are selected such that a spur of smaller cross-sectional dimensions than those of the rod is formed in the axis of the hollow body from the closing zone in a direction contrary to the direction of withdrawal of the rod.