JPS6293821A - Vacuum discharge apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Fields] This invention uses a low melting point, high vapor pressure metal at the contact part of the electrode in order to obtain a low breaking current for vacuum circuit breakers, vacuum lightning arresters, vacuum type 8-point gears, etc. The present invention relates to a vacuum discharge device that includes a vacuum discharge device and does not have an exhaust tip tube.

[Prior art] An example of the configuration of a conventional vacuum discharge device is disclosed in Japanese Patent Publication No. 59-8980.
The conventional vacuum breaker of the type that does not include an exhaust step pipe will be explained. In Fig. 2, %1a and 1b are fixed electrodes and movable electrodes, 2 is a bellows, 8a and 8b are fixed flanges and movable flanges, 4 is a shield, and 5 is an insulating cylinder. It is joined to adjacent members to form a sealed vacuum container. Generally, the electrode contact members are made of a copper alloy containing low melting point metals such as bismuth Bi, tellurium, Te% antimony sb, and lead Pb, the bellows 2 is made of austenitic stainless steel, and the flanges 8a and 8b are made of Kova.
r (16C.

The shield 4 is made of materials such as Cu and Ni%Fe, and the insulating tube 5 is made of alumina porcelain. .

Next, a manufacturing process of a vacuum breaker according to the prior art will be explained. The vacuum breaker shown in Figure 2.

First, the fixed side electrode 1a and flange 8a are assembled in advance by furnace atmosphere brazing or vacuum brazing, and the movable side electrode 1b, bellows 2° and flange 3 are assembled in the same way.
Assemble b and beforehand. The shield 4 is then attached to the insulating tube 5 in an appropriate manner.

Thus, the fixed side assembly groove body 10 and the movable side assembly structure 20
The sealing brazing materials 40a and 40b are inserted between each of the eight members of the shield insulating cylinder assembly structure 30, and a low-pressure atmospheric gas is introduced into the vacuum furnace. is heated to melt and solidify the brazing filler metals 40a, 401), thereby completing the required sealed vacuum container.

As discussed in Japanese Patent Publication No. 59-8980, the problem with vacuum brazing is the reliability of the sealed parts when brazing stainless steel members containing chromium Cr.

Since the reducing effect in a vacuum is weaker than in a hydrogen furnace, brazing stainless steel parts containing Cr, which has a high affinity for oxygen, requires a temperature of approximately 950°C or higher;
When heated above .degree. C., the elastic function of the bellows 2 decreases, resulting in a problem that the mechanical opening/closing life of the vacuum breaker is shortened. Therefore, the pressure in the vacuum furnace is 10-”
By introducing low-pressure inert gas or reducing gas such as hydrogen or a mixture of these gases, the brazing temperature in a vacuum furnace can be kept lower than 950°C while brazing stainless steel. Methods have been proposed to maintain the sealing reliability of the parts.

(Problems to be Solved by the Invention) A conventional vacuum breaker of the type that does not include an exhaust tip tube is constructed as shown below, and it supplies low-pressure inert gas and hydrogen gas to the vacuum furnace. After introduction, the brazing is sealed (1) This traps inert gas or hydrogen gas in the vacuum container, which may result in poor vacuum quality, which may affect production yields. I can't say it's in good condition either.

B1Te is included in the contact material of the electrode.
In low-pressure vacuum brazing, the high vapor pressure of low-melting point metals such as Sb and Pb acts on the sealed joint. Therefore, it was extremely difficult to manufacture a highly reliable vacuum breaker.

This invention was made to solve the above-mentioned problems, and has high sealing reliability without leaving any residual gas in the vacuum container, and without contaminating the sealing joint with metal vapor from a low-melting point metal. The purpose of the present invention is to economically provide a vacuum breaker and a vacuum discharge device with high yield, which have low breaking current and are easy to handle because they have no exhaust chip tube.

[Means for Solving the Problems] A vacuum discharge device according to the present invention includes a hydrogen storage alloy inside a vacuum container, and a part of the metal member of the vacuum container is made of a hydrogen permeable member. Using silver copper solder 7as7b containing palladium for joining the member to the electrode member,
It is characterized by using silver-copper eutectic solder 40a%40b, which does not contain palladium, to bond the metal member to the ceramic (vacuum vessel insulating member), and the metal member is bonded to the ceramic (vacuum vessel insulating member) by the action of a large amount of high-purity hydrogen gas released from the hydrogen storage alloy. Therefore, extremely reliable brazing provides a sealed W part. In addition, brazing is performed in a vacuum after the sealing is completed, and brazing is performed in a non-hydrogen atmosphere by heating at an intermediate high temperature lower than the temperature during sealing to pass the hydrogen permeable member through the inside of the vacuum container. The remaining hydrogen gas is exhausted to the outside of the vacuum container.

In the vacuum discharge device of this invention, vacuum brazing releases high-purity hydrogen gas from the hydrogen storage alloy by heating during sealing, and the inside of the vacuum container is heated (compared to the conventional low-pressure vacuum method).
As a result of being filled with high-pressure hydrogen gas, the evaporation of the low-melting point metal in the contact is suppressed, and brazing strongly reduces the sealing area, so conventional vacuum brazing in low-pressure hydrogen is no longer possible. It is possible to achieve sealing using brazing that is much superior to that of conventional methods. Matoko,
Since brazing has a stronger reducing effect on the sealing part than conventional methods, brazing allows the temperature to be set lower (than conventional), and as a result, the mechanical opening/closing life of the bellows can be extended.

In addition, when exhausting hydrogen gas through the hydrogen permeable member after brazing is completed, the hydrogen partial pressure must be 1 x 10-'Tor.
(r) Heating may be done in an inert gas such as nitrogen gas, or in the case of B, while exhausting the hydrogen gas, or if there is a leak hole in the sealing part or the wall of the vacuum vessel. if,
It becomes possible to simultaneously verify the presence or absence of this leak and its magnitude.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1st
In the figure, 1a and Ib are fixed electrodes and movable electrodes,
2 is a bellows, 8a and 8b are fixed flanges and movable flanges, 4 is a shield, and 5 is an insulating cylinder.

All the other members except for the shield 4 are hermetically joined to adjacent members to form a vacuum container, and the materials of these constituent members are 7a%7b, 40a, 40
1 shown in FIG. 2 is the same as the conventional example except for b.

The first feature of this invention is that the hydrogen storage member 6 is housed inside a vacuum container. Hydrogen storage material is titanium T
it tantalum Ta s niobium Nb, zirconium Z
Made of single metals such as r or alloys containing these,
It is installed in a location where the electric field is relatively low so as not to affect the withstand voltage characteristics of the vacuum breaker.

The second feature of the present invention is that part or all of the metal members of the vacuum container are made of a hydrogen permeable member. In this embodiment, the bellows 2. The fixed flange 3a and the movable flange 3b are configured as hydrogen permeable members. In other words, the bellows 2 is Ti and the one is Ta.

It is made of austenitic stainless steel containing Nb, and the fixed flange 3a and movable flange 3b are made of a copper-Cu alloy or a nickel-N+ alloy containing palladium Pd. These hydrogen permeable members are made of conventional austenite 1-stainless steel or Kovar.
) It is characterized by a hydrogen permeability that is about 10 times higher than that of alloys.

Although it is similar to the vacuum breaker of the prior art, the fixed side assembly structure 10 and the movable side assembly structure 20 are pre-brazed with silver-copper brazing material 7a%7b containing palladium. A low-pressure atmospheric gas (hydrogen pressure approximately IQTorr) is introduced into the three members of the shield/insulation cylinder assembly structure 30 and the sealing brazing materials 40a and 40b into a high vacuum or a vacuum furnace to heat the entire vacuum breaker. . In this embodiment, the sealing solder materials 40a and 40b are eutectic silver solder (approximately 72Ag-28Cu
).

At the start of heating, the hydrogen storage member 6 of the present invention starts to release its built-in hydrogen as the temperature rises, and almost all of the built-in hydrogen is released at the melting point of the eutectic silver solder (approximately 780° C.).Temperature rise Speed.

The hydrogen pressure inside the vacuum container changes depending on the size of the exhaust conductance determined by the gap between the sealing brazing fillers 40a and 40b, but in this example, a maximum pressure exceeding about 200 Torr was recorded.

In addition, when the eutectic silver solder melts, the vacuum-tight solder parts of the stationary side assembly structure 10 and the movable side assembly groove body 20 are also exposed to the
Since the brazing filler metals 7a and 7b are heated to a high temperature of 0° C., the brazing materials 7a and 7b may be in a semi-molten state, resulting in a problem that the reliability of the airtight joint is reduced.

The eighth feature of the present invention is that silver copper containing palladium within 10.5% is used as the first brazing material, so that the solidus line is 78.
Since the temperature was higher than 0° C., it was possible to completely prevent problems with the writing.

The generation of high-temperature, high-purity hydrogen gas at a relatively high pressure significantly suppresses the evaporation of the low-melting-point, high-vapor-pressure metal contained in the electrode contacts, and also prevents vacuum brazing from sealing. Since the reducing effect of the bonded part is also strong, it was possible to obtain an extremely good brazing and sealing part.

By melting (melting falls off) the brazing filler metal in the sealing area.

The inside and outside of the vacuum container are cut off, but at this time, the hydrogen trapped inside the vacuum starts to be absorbed into the hydrogen storage member 6 by the rapid cooling operation after the melt melt falls, and slowly cools to room temperature. In this case, the total pressure inside the vacuum vessel is 5 x 1
0-” Torr and 1:.

After that, the vacuum breaker is heated again in vacuum at a temperature of 600°C. The second feature of this invention is the hydrogen permeable member (
2. Confirm that the hydrogen trapped inside the vacuum vessel is exhausted to the outside of the vacuum vessel through (aa, 8b). In the practical example, the material was heated at 600°C for 2 hours, then slowly cooled to room temperature, and the total pressure inside the vacuum breaker after 1 hour was 3 x
At 10-' Torr.

In the above embodiment, vacuum brazing is performed by cooling to room temperature and then vacuum heating again after sealing, but in reality, eutectic silver is soldered without first cooling to room temperature. Approximately 600 liters immediately from the melting point of wax (approximately 780 tl: )
By slowly cooling the hydrogen to the hydrogen exhaust temperature of .degree. C., the above-mentioned exhaust time of 2 hours can be further shortened.

Furthermore, in the above example, the final brazing sealing was carried out in a high vacuum or in a low pressure hydrogen of about 10 Torr, but this was carried out in a hydrogen furnace of about 760 Torr (1 atmosphere), After that, it is also possible to exhaust the hydrogen gas inside the vacuum container in a vacuum atmosphere. As a result, the total pressure inside the vacuum container after cooling to room temperature was about I x 10-'Torr, and the required withstand voltage for a vacuum discharge device was obtained.

Furthermore, in another example, when the fixed flange 8 as and the movable flange 8 b were made of austenitic stainless steel containing % Ti and Tan Nb, a good withstand voltage could be obtained.

[Effects of the Invention] As described above, according to the present invention, a hydrogen storage member is provided inside the vacuum container, and the metal member of the vacuum container is made of a hydrogen permeable member. Brazing of a discharge device having a high vapor pressure metal can completely prevent contamination of the sealing part with the high vapor pressure metal, and has high yield and high sealing reliability.

Another advantage is that a vacuum discharge device without an evacuation tip can be produced stably and economically.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a vacuum discharge device according to an embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional vacuum 1-7 and a disconnector. In the figure, la is a fixed electrode, 1b is a movable electrode, 2 is a bellows, 3a is a fixed flange, 8b is a movable flange, 4 is a shield, 5 is an insulating cylinder, 6 is a hydrogen storage member, 7a
%7b is silver copper brazing filler metal containing palladium, 40 a h4
0b is a silver-copper eutectic brazing filler metal. In Figure 5, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] In a vacuum discharge device of a type having at least one pair of electrodes in a vacuum, a contact portion of the electrodes containing a low melting point metal, and having no exhaust tip tube, a hydrogen storage member is provided inside a vacuum container, and a metal member is provided. A part or all of the metal member of the vacuum container constituted by a hydrogen permeable member and an insulating member, and the electrode and the metal member for the vacuum container are joined with a silver-copper brazing material containing palladium, and the A vacuum discharge device characterized in that a metal member for a vacuum container and an insulating member are joined using a silver-copper eutectic brazing material.