JPH03110749A - Electrode for water cooling type electric discharge lamp - Google Patents

Abstract

PURPOSE:To lengthen the life of an electrode by covering a base metal composed of a hollow copper member by a thin sheet made of tungsten from the front surface to the side surface, and thereby joining said thin sheet with the base metal by means of welding. CONSTITUTION:A base metal 1 made up out of a hollow copper member includes a flat section 11 at its front side, a tapered section 12 and a side section 13, and its inside water cooling section is provided with a number of heat radiating fins 2. The flat section 11, the tapered section 12 and the side section 13 of the base metal 1 is covered by a thin sheet 3 made of tungsten while being joined with the base metal 1 by means of welding. Since the base metal is covered by a tungsten sheet from the front surface to the side surface, possible electrodes damage caused by arc sparks can thereby be reduced. In addition, the base metal made of copper is joined with the tungsten sheet by means of welding, the life of the electrode can thereby be lengthened with its stabilized quality.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a water-cooled electrode used in a high-output discharge lamp filled with a discharge gas such as xenon.

[Prior technology] Solar simulators (space environment equipment used for solar irradiation tests in a vacuum outside the atmosphere) used for space development and arc image furnaces (discharge lamps) used for research on ultra-high temperature materials. Devices that optically focus radiant heat to melt heat-resistant materials are filled with rare gases such as mercury, xenon, and argon, and the pressure at the time of lighting is 1.
Short-arc type high-pressure discharge lamps with a discharge voltage of 0 atmosphere or more have been used, but recently, with the increase in the size of equipment, high output lamps are required, and large lamps with a capacity of about 50 kW are being developed.

However, large ones have high voltage and high current (e.g. 3
In the case of a 0KW xenon short arc discharge lamp, the distance between the electrodes is 131. (45V, 660A), which generates high heat, so a water-cooled type anode is used, and the material used is copper, which has good thermal conductivity.

The thinner the thickness of the copper base metal, the higher the cooling efficiency, but the reality is that it cannot be less than 1.51 when conditions such as mechanical strength are taken into consideration.

Conventionally, this water-cooled anode has been made of copper or copper plated with rhodium, but as mentioned above,
For ultra-large products that carry a current of 00A or more, some are of the type that uses a brazing material to join a thin plate of Dungesten to the part that is hit by the arc, in order to prevent the copper from melting due to temperature rise.

FIG. 4 is a side view showing a schematic structure of the anode part of a conventional water-cooled discharge lamp electrode, in which 1 is a hollow base metal made of copper that constitutes the anode of the discharge lamp electrode, and 2 is the base metal l. A radiation fin 3 for cooling is a thin plate made of Dungesten provided at the tip of the anode, and the base metal 1 and the thin plate 3 are joined by a brazing material 4.

In the electrode of FIG. 4, during operation the base metal l made of copper is
In order to prevent the temperature of the thin plate 3 made of tungsten from rising, water is poured into the hollow part of the electrode made of the base metal l and the thin plate 3 to cool it and prevent the tip of the electrode from melting or evaporating.

[Problems to be Solved by the Invention] As mentioned above, in the conventional water-cooled discharge lamp electrode,
Copper, the base metal of the electrode, and a thin tungsten plate attached to the surface of the copper were bonded together using a brazing material.
It is difficult to keep the thickness and uniformity of this brazing filler metal constant;
Therefore, if the thickness or uniformity of the brazing filler metal differs, there is a problem in that the heat generated by the arc of the electrode is not uniformly and efficiently transferred to the cooling water.

In addition, the brazing material itself has low thermal conductivity, which not only reduces cooling efficiency but also makes it difficult to make the thickness uniform.
There is a problem in that it is difficult to cover the entire surface of the copper (including the side surfaces), that is, the entire surface of the copper in contact with the arc, with a thin tungsten plate.

The present invention has been made to solve the conventional problems, and an object thereof is to provide an electrode, particularly an anode structure, for a water-cooled discharge lamp that can be used satisfactorily even in the case of a large current.

[Means for Solving the Problems] In order to achieve the above object, the electrode for a water-cooled discharge lamp of the present invention covers a hollow base metal made of copper with a thin plate made of tungsten from the front side to the side thereof, and It has a structure in which the base metal and the base metal are fused and bonded.

[Effect] This invention has the above configuration.

■Since the front and sides of the anode are covered with a thin tungsten plate, no copper is exposed in the area that comes into contact with the arc.

■The thin tungsten plate and the copper base metal are directly connected by fusion bonding, so the arc heat is evenly and efficiently transmitted to the cooling water.

[Embodiment] FIG. 1 is a sectional view of an anode portion showing an embodiment of the present invention. In FIG. 1, a base metal 1 made of hollow copper is
It has a flat part 11 on the front, a tapered part 12, and a side part 13, and a large number of radiation fins 2 are provided in the water-cooled part inside. Flat portion 11 of this base metal l. Tapered portion 12. The side surface portion 13 is covered with a thin plate 3 made of tungsten, and is connected to the base metal 1 by fusion bonding.

Specifically, for example, the thickness of a thin tungsten plate is 1.5.
, , and the thickness of the base metal (copper) is l~t, S, in the part covered with tungsten, and 31. in the part not covered with tungsten. It is.

Next, a method for manufacturing this anode portion will be described.

The thin tungsten plate that covers the front and side surfaces of the base metal l can be manufactured, for example, by cutting out a tungsten body of a predetermined size by machining.

Next, a thin tungsten plate shaped into a predetermined shape was placed in a carbon jig, and a sufficient amount of copper was placed on top of it as required for the final shape, and after melting in an N2 atmosphere (temperature 1100°C), After being cooled and solidified, it is further melted again in an N2 atmosphere (at a temperature of 1100° C. or higher), and then cooled and solidified to join the copper and tungsten thin plates.

The electrode obtained by the above method is a bonded product of dense copper and tungsten thin plates without bubbles.

Finally, the outer periphery of the electrodes bonded in this manner is finished by machining to obtain the desired dimensions.

Further, FIG. 2 is a sectional view showing another embodiment/example of the present invention, showing a specific example in which the thin plate 3 made of tungsten covers the base metal l up to the tapered portion.

Furthermore, FIG. 3 is a sectional view showing still another embodiment of the present invention, and shows a specific example in which the tip is spherical.

In addition, in both FIGS. 2 and 3, the same reference numerals are used for the same or equivalent parts as in FIG. 1, and the manufacturing method and operation of these structures are the same as in FIG. 1, so explanations will be omitted. do.

[Effects of the Invention] As explained above, the electrode for a water-cooled discharge lamp of the present invention has the following effects.

■Since the front and sides are covered with a thin tungsten plate, electrode damage from arcing is reduced.

■Since the base metal made of copper and the thin tungsten plate are connected by fusion bonding, the quality is stabilized.

■As a result, the life of the electrode can be extended.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an anode section showing one embodiment of the invention, FIG. 2 is a sectional view showing another embodiment of the invention, and FIG. 3 is a sectional view showing still another embodiment of the invention. , FIG. 4 is a sectional view showing a schematic structure of an anode portion of a conventional electrode for a water-cooled discharge lamp. In the figure. l: Base metal 2: Radiation fin 3: Thin plate made of tungsten 4: Brazing material 11: Flat part 12: Tapered part 13: Side part

Claims (1)

[Claims] 1. An electrode for a water-cooled discharge lamp, characterized in that a hollow base metal made of copper is covered with a thin plate made of tungsten from the front to the side, and the thin plate and the base metal are fused and bonded.