Patent Treuhand Gesellschaft Fur Elektrische Gluhlampen Mbh

Patent-treuhand-gesellschaft F. Elektrische Gluehlampen Mbh

Dieter Hofmann

Stefan Juengst

Erolf Weinhardt

Ernst Panofski

Lutz Klein

Helmut Grahmann

Wolfgang Albrecht

Alfred Wacker

To provide a tight seal between an essentially solid niobium or tantalum necting pin or rod (10) passing through an opening (7, 28) in an end plug (11) closing off a high-pressure discharge lamp discharge vessel (8), the pin or rod is formed with two axial portions, one of which has externally projecting continuous rings (17), preferably two or three, or an externally projecting thread (26). The rings or thread are press-fitted into the end portion of the bore in the plug, which deforms the edge (20) of the rim, ridge or thread, or shears off the edge portion, ensuring a tight preliminary fit in the bore; sealing glass, which is then melted to fill a capillary space between the pin or rod and the plug, is protected by the preliminary seal against corrosion or attack from the fill within the discharge lamp; if the projection is in form of a thread, glass can penetrate within the threads to further seal and retain the pin or rod. Diffusion-welding of the threads or ridges to the walls of the plug can also be used.

High-pressure electric discharge lamp with tight lead-through pin

To improve the stability of operation of a compact, single-ended fluoresc lamp under 'base down' operation, and provide for a predetermined temperature 'cold spot' defining the vapor pressure within the fluorescent lamp, and particularly for a lamp having four parallel tubular portions which are interconnected to form a continuous discharge vessel, one of the tubular portions which does not carry an electrode has a small tube or stub element (16) connected into a pinch seal terminating the particular tubular element, the stub element extending below the pinch seal and into the base of the lamp. The lamp is formed with two vertically arranged openings to provide for passage of cooling air, by thermal convection, from a lower opening (17), past the cooling tube or stub (16) and to an upper outlet vent opening (19). A socket, in which the lamp may be inserted, is preferably likewise formed with openings to permit passage of air thereinto, from a lower side to an upper opening which matches the alignment of the opening in the lamp base. Combination of such a lamp, with a lamp base with lamp operating circuit components, is readily possible, in which case the lamp operating circuit components are preferably located within an adapter of a housing element which includes an opening with a guide tube to guide cool air leading to the cooling tube. Under 'base down' operation, mercury within the fill of the fluorescent lamp may condense and flow down, to collect as a mercury droplet in the cooling tube or stub, to thereby establish the vapor pressure within the discharge vessel.

Compact, single-ended fluorescent lamp with fill vapor pressure control

The amount of emitter paste which can be applied to the filament used in orescent tubes can be increased by winding the filament, as previously proposed, about an iron or molybdenum mandrel which can be dissolved; in contrast to the prior art, however, the wound filament is not annealed at a temperature which removes winding stresses but, rather, at a lower temperature of about for example 900.degree. C. for tungsten wire, thus retaining some of the winding stresses. Upon dissolving-out of the iron core or mandrel, the remaining stresses will cause adjacent windings of the filament to slightly relieve their stresses by springing back to some extent, resulting in relatively offset end portions of the wires with respect to each other, when the wires have been wound on a mandrel which has an essentially rectangular cross section in which the ratio of length to width--in cross section--is greater than 2. The resulting surface roughness of an envelope of the filament permits retention of a larger amount of emitter material with better retention capabilities, and thus increases the lifetime of lamps by about 30% with respect to lamps having filaments in which adjacent windings are congruent.

Lamp filament structure, and method of its manufacture

To reduce the operating temperature of a U-shaped or multiple U-bent fluocent lamp, the respective longitudinal and transverse sectional elements of the U-shaped lamp are so related that the outer generating line M.sub.Q of the individual transverse tube sections (4; 20, 21, 22) is substantially straight;

Low-pressure mercury vapor discharge lamp, particularly U-shaped

The lamp has a pinch seal which surrounds a mounting structure carrying l-in wires of the filament;

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Augsburg, Germany

Dieter Hofmann