DE2619505A1 - SHORT ARC LAMP - Google Patents

Description

German ITT Industries GmbH A.M.V. Taxil et al 26-7-2 Hans-Bunte-Str. 19, 7800 Freiburg Dr.Rl / sp

April 28, 1976

DEUTSCHE ITT INDUSTRIES GESELLSCHAFT LIMITED LIABILITY

FREIBURG I. BR.

Short arc lamp

The priority of application no.75 14272 dated May 7, 1975 in France is claimed.

The present invention relates to a short arc lamp with a power of 200 to 1000 watts / cm arc length works, in which the metal connections between the electrodes and the sockets, which have a high temperature, are protected by noble gas or chemically inert gas in a sealed envelope .

A short-arc lamp working with high power is usually subject to strong heating by the small-volume ones Pistons distributed high energy. One of the main reasons for these lamps to fail is the sensitivity of the metallic connections against oxidation by air. This is especially true

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the case when the connections are made from molybdenum. This metal is compatible with the refractory material from which the pistons, usually made of quartz, are made. Molybdenum connections are not able to withstand temperatures above 350 ⁰ C in the air without degradation and are the cause of the destruction of the connection seals. As a result, the power that can be applied to such a lamp under these conditions is limited.

The invention is therefore based on the object of molybdenum compounds to create, which are able to withstand much higher temperatures and which do not oxidize when performances of 200 to 1000 watts / cm on the lamp.

Furthermore, it should be ensured that the temperature of the metallic base does not exceed ^{350 ° C. under these conditions.}

The object is achieved by the invention specified in claim 1.

The invention provides a lamp is thus created, consisting of a quartz envelope, the two tubular axial extensions has, both of which constitute a sealed protective envelope containing protect _r around therethrough metallic compounds, an inert gas or an inert gas.

According to a further feature of the invention, the two sheaths each closed by two seals, each of which is traversed by the molybdenum conductors, the conductors being the first seal are connected to one electrode and the second seal to the lamp base. _

In this way, the conductors and the connections of these conductors, all consist of molybdenum "even at operating temperatures of 800 to 1000 ⁰ C is not oxidized long.

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It is then possible to have a higher electrical output on the lamp to create and thus to increase their light output. This possibility is particularly advantageous when the lamp bulb contains an atmosphere in which, in addition to other constituents, metal halides are included, which must still have a high temperature at the coolest point of the piston in order to have a high Ensure light output.

Further features of the invention can be found in the following detailed description. Description and drawing serve only as an example and do not limit the scope of the invention in any way.

The only figure is a longitudinal section through a short-arc lamp according to the present invention.

The cylindrical piston 1 has two symmetrical tubular lugs 2 and 2a. For the sake of simplicity, only one of the two approaches has been used and is described in detail below. The piston 1 consists of a refractory material, such as. B. Quartz, and is provided with two electrodes 3 and 3a. Each of the electrodes preferably consists of a tungsten-thorium rod 4, the end zone of which in the piston of a spiral 5 made of tungsten-thorium wire is surrounded. The other end of the rod is welded to a molybdenum conductor 6, which has the shape of a thin strip 'or brazed.

The piston 1 can, for. B. with an atmosphere of at least one Noble gas, known amounts of mercury and metal halides and ' optionally free halogen or a halogenated organic compound. The tubular extension 2 or 2a contains a tubular envelope 7, which is closed by a first seal 8, which by squeezing off the extension 2 on the molybdenum sap 6 is produced. The sheath 7 has a

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the first seal 8 corresponding seal 9 around the second Molybdenum strips 10. The molybdenum strips 6 and 10 are completely embedded in the quartz due to the compression. Your ends are soldered to the metallic connections 11 and 12, the z. B. may consist of molybdenum and the other ends protrude into the sheath 7, where they are connected to a metallic conductor 13 which can be made of a wire or a band of copper or nickel or some other hxtzebeständxgen metal.

Each of the lugs 2 and 2a terminates with a tubular end piece 14, which is open at one end. This end piece 14 is covered by a metal base 15 in the manner as described in French patent application 74 12 746 will.

A molybdenum rod protruding axially through the end of the end piece 14 16 is on the strip 10 and on one end of the copper wire 17 connected. The other end of the wire 17 is melted or brazed into the central bore 18 of the base.

The sealed envelope 7 contains a noble gas or inert gas, such as z. B. argon or nitrogen. This gas protects the metal connections 11, 12 and 13 in the tubular extension 2 against oxidation, when the lamp is at its maximum level and reaches a high temperature.

The dimensions of the lamp are related to the required output. A power of 200 to 1000 watt / cm can be achieved if the distance between the electrodes 3 and 3a is between 10 and 30 mm. In order to avoid exceeding the temperature of 350 ^° C. at the base, the axial distance between the second seal and the center of the piston should be two to ten times the distance between electrodes 3 and 3a. The coolest temperature

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of the bulb is then between 800 and 100 ⁰ C. This temperature improves the generation of an intense light spectrum by the metal halides, while the conductors 6 and 10 and the metal compounds 11, 12 and 13, whose temperatures rise to 350 to 1000 ⁰ C, through the Protective gas contained in the sealed envelope 7 is completely protected against oxidation.

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Claims (6)

2819505 Ä.M.V. Taxil et al 26-7-2 CLAIMS 1.J Short arc lamp, consisting of a quartz bulb with a tungsten Thorium electrodes, soldered to molybdenum conductors, which are embedded in a first seal that closes the flask, the flask being filled with an atmosphere consisting of at least one noble gas, mercury, metal halides and optionally free halogen or a halogenated organic compound consists, characterized in that it has an axial tubular extension (2, 2a) on each side, which consists of a sealed protective sheath (7) which is secured by the "first seal (8) of the piston (1) and the second seal ( 9) is closed on the »second molybdenum conductor (10), and that the shell (7) contains an atmosphere consisting of at least one noble gas or a chemically inert gas. 2. Lamp according to claim 1, characterized in that the molybdenum conductor (S ^ 10} in the first and second seals (8 "9) of the tubular extension / 2) are embedded and. by metallic connections (11 _{B 12?} 13), which traverse the atmosphere of the protective envelope (7) communicate with each other. 3 »Lamp according to claim. 2 " characterized in that the axial distance between the second seal (3) and the center of the bulb (1) is two to ten times the distance between the two electrodes (3 _B 3a} when the power applied to the lamp is between 200 and 1000 watts / cm. 4 '' lamp according to claim 1, characterized in that the second seal _B (9} axially by a tubular end piece (14) SO 9847/0329 A.M.V. Taxil et al 26-7-2 is extended, which is surrounded by a metal base (15) and that the conductors in the second seal (9) are connected to the base via a wire (17) and a solder joint. 5. Lamp according to claim 1, characterized in that the noble gas or the inert gas is argon or nitrogen. 6. Lankpe according to claim 2, characterized in that the connections (11, 12, 13) are made of molybdenum, copper or nickel. , 609847/0329 Blank page