# US 8,786,187 B2 · Discharge lamp with an outer bulb surrounded by a wire gauze as explosion protection

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- Number: US 8,786,187 B2
- Document ID: US8786187B2
- Status: Granted
- Kind: B2
- Application number: 13/885,408
- Filed: 2011-11-07
- Published: 2013-10-31
- Granted: 2014-07-22
- Earliest claimed: 2010-11-17
- Assignees: OSRAM GmbH
- Applicants: Johannes Buttstaedt; Stefan Dunkel; Andreas Genz; Maik Hegewald
- Inventors: Johannes Buttstaedt; Stefan Dunkel; Andreas Genz; Maik Hegewald
- Web page: https://patentgrep.com/patent/US8786187B2

## CPC

- H01J 17/16: Vessels; Containers
- H01J 61/34: Double-wall vessels or containers
- H01J 61/50: Auxiliary parts or solid material within the envelope for reducing risk of explosion upon breakage of the envelope, e.g. for use in mines
- H01J 61/827: {Metal halide arc lamps}
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

A bushing for a high-pressure discharge lamp, which is suitable for connecting an electrode in the interior of a ceramic discharge vessel to a supply lead in a gastight manner on the exterior of the discharge vessel, wherein the bushing is an electrically conductive ceramic composite consisting of a mixture of LaB6 and at least one second material from the group Al2O3, Dy2Al5O12, AlN, AlON and Dy2O3 is disclosed.

## Claims

### Claim 1

A high pressure discharge lamp comprising a discharge vessel sealed in vacuum-tight fashion, said discharge vessel defining a longitudinal axis, containing an ionizable filling and two electrodes and being enclosed by an outer bulb, wherein the outer bulb has a cylindrical central part, wherein at least the cylindrical central part is closely surrounded by a wire gauze as explosion protection, wherein the wire gauze is characterized by the wire diameter and the mesh length of the gauze, and wherein the ratio of mesh length to wire diameter is in the range of 25 to 60, boundary values inclusive,
wherein the outer bulb further comprising a plurality of ends tapering relative to the central part, and
wherein end regions of the wire gauze each have a reduced mesh width so that the wire gauze adheres to the outer bulb without any mount.

### Claim 2 (depends on 1)

The lamp as claimed in claim 1, wherein in the region of the central part the ratio between the regular gauze area in square millimeters to the lamp power in watts is between 10 and 35, boundary values inclusive.

### Claim 3 (depends on 1)

The lamp as claimed in claim 1, wherein the ratio between the length of the cylindrical central part and the mesh length is in the range of 3 to 12, boundary values inclusive.

### Claim 4 (depends on 1)

The lamp as claimed in claim 1, wherein the ratio between the circumference of the cylindrical central part and the mesh width of the gauze is between 5 and 20, boundary values inclusive.

### Claim 5 (depends on 1)

The lamp as claimed in claim 1, wherein the discharge vessel contains metal halides.

### Claim 6 (depends on 1)

The lamp as claimed in claim 1, wherein the wire gauze has at least one end region in which the length of the meshes is reduced relative to the main region by at least 30%.

### Claim 7 (depends on 1)

The lamp as claimed in claim 1, wherein the outer bulb is produced from quartz glass.

### Claim 8 (depends on 1)

The lamp as claimed in claim 1, wherein the wire gauze bears directly on the outer bulb or a part thereof.

### Claim 9 (depends on 1)

The lamp as claimed in claim 1, wherein the wire gauze is applied in a double layered fashion at least in sections.

### Claim 10 (depends on 1)

The lamp as claimed in claim 1, wherein the discharge vessel comprises sodium as metal of the halide.