Method of making a discharge vessel for compact low-pressure discharge lamps

US4801323A · kind A · utility

Assignee

• Patent-Treuhand-Gesellschaft fur elektrische Gluhlampen mbH · DE

Inventors

• Lutz Klein · Scheuring, DE
• Ernst Panofski · Augsburg, DE
• Gerd-Otto Eckstein · Augsburg, DE
• Hans Schmidt · Ried im Innkreis, AT
• Josef Plischke · Augsburg, DE

Key dates

• Filing date: May 19, 1987
• Grant date: Jan 31, 1989
• Expiry date: May 19, 2007

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02B20/00
• WIPO field: Other special machines
• WIPO sector: Mechanical engineering

Abstract

A tubular discharge vessel for a compact low pressure discharge lamp, espally a compact fluorescent lamp, is formed by heating and bending a straight glass tube into a U-shape with a plurality of straight sections and a 180.degree.-bend. Adequate vessel wall thickness is assured at the tubular sections where the bends are formed, by first heating a central section, moving sections lateral to the central section axially toward one another, thereby compressing the heated central section and thickening its walls, and bending or rotating the lateral sections into a parallel orientation. This prevents the bending process from unduly thinning the vessel walls, leading to breakage or rupture under internal gas pressure.