JPS6255821A - Vacuum discharger - 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] [Field of Industrial Application] This invention uses a low melting point and high vapor pressure at the contact part of the electrode in order to obtain a low disconnection current in vacuum circuit breakers, vacuum lightning arresters, vacuum three-point gaps, etc. The present invention relates to a vacuum discharge device that includes metal and does not have an exhaust tip tube.

[Conventional technology]

An example of the configuration of a conventional vacuum discharge device is shown in Japanese Patent Publication No. 59-89-3.
A vacuum breaker of the type that does not include a conventional exhaust tip pipe will be described. In Figure 2, la and lb are fixed electrodes and movable electrodes, 2 is a bellows, 3 &
and 3b are a fixed 7 flange and a movable flange, 4 is a shield, and 5 is an insulating cylinder; these members except the shield 4 are joined to mutually adjacent members, and constitute a sealed true chamber container. .

-Bismuth B1 and tellurium Te are used as the contact member of the Ill electrode.
The bellows (2) are made of copper alloy containing low melting point gold such as antimony sb or lead Pb.
co-29NiH1e) Also, the shield 4 is made of a material such as Cu%Nt, rattan or stainless steel, and the insulating cylinder 5a is made of alumina porcelain.

Next, a manufacturing process of a vacuum breaker according to the prior art will be explained. In the vacuum breaker shown in FIG. 2, the fixed side electrode 1a and the 7-lunge 3a are assembled in advance by furnace atmosphere brazing or vacuum brazing, and the movable side electrode 1b and bellows 2 are assembled in advance. , 7 langes 3b are assembled in advance. The shield 4 is then attached to the insulating tube 5 in an appropriate manner.

Thus, the fixed side assembly structure 10 and the movable side assembly structure 20
A sealing brazing material 40a, 40b is inserted between each of the three members of the and shield insulating cylinder assembly structure 30, and low pressure atmospheric gas is introduced into a vacuum furnace or a vacuum furnace to heat the whole and melt the brazing material. 40a and 40b are melted and solidified to complete the required sealed vacuum container.

As discussed in the above-mentioned Japanese Patent Publication No. 59-8930, the problem with vacuum brazing is that stainless steel containing chromium or
Brazing of I-materials is a matter of reliability of the sealing part.

In a vacuum, the reducing effect is weaker than in a hydrogen furnace, so brazing stainless steel parts containing Or, which has a high affinity for oxygen, requires a temperature of about 950°C or higher;
If heated above ℃, the elastic function of bellows 2# will be reduced, resulting in a problem that the mechanical opening/closing life of the vacuum breaker will be shortened. Therefore, due to the pressure in the vacuum furnace, from Torr to 1O-
By introducing a low-pressure inert gas of 3 Torr, a reducing gas such as hydrogen, or a mixture thereof, brazing in a vacuum furnace can suppress the temperature lower than 950°C while brazing stainless steel. ) Methods for maintaining sealing reliability have been proposed.

[Problem that the invention seeks to solve]

A conventional vacuum breaker of the type not equipped with an exhaust tip tube is constructed as described above, and low-pressure inert gas or hydrogen gas is introduced into the vacuum furnace.

Since the mounting was sealed, inert gas or hydrogen gas could be trapped inside the vacuum container, resulting in poor vacuum quality, so manufacturing yields were not necessarily good. .

In addition, B1, Te, contained in the contact material of the electrode,
Since the high vapor pressure of low-melting point metals such as 8b and Pb acts on the sealed joints even in low-pressure vacuum brazing, brazing significantly reduces the joint strength of the sealed parts. However, it was extremely difficult to manufacture a highly reliable vacuum breaker.

This invention was developed to solve the above-mentioned problems, and it does not leave any residual gas in the vacuum container, and also provides high sealing without contaminating the sealing joint with metal vapor from a low melting point metal. The aim is to provide the #1 economical vacuum breaker and vacuum discharge equipment with high yield, which are characterized by reliability, have low breaking current, and are easy to handle due to the absence of exhaust chip tubes. It's pointing.

[Means for Solving the Problems] The vacuum discharge device according to the present invention is characterized in that a vacuum container is provided with a hydrogen storage alloy inside the vacuum container, and a part of the metal member of the vacuum container is made of a hydrogen permeable member. , an extremely reliable brazing process achieves a seal due to the action of a large amount of high-purity hydrogen gas released from the hydrogen-absorbing alloy. In addition, after the sealing is completed, brazing must be heated in a vacuum or in a non-hydrogen atmosphere at an intermediate high temperature lower than the temperature during sealing. It is designed to exhaust hydrogen gas to the outside of the vacuum container.

[Function J] The vacuum discharge device of this invention has the advantage that in vacuum brazing, high-purity hydrogen gas is released from the hydrogen-absorbing alloy by heating during sealing, and a high pressure of 5Iri (compared to the conventional low-pressure vacuum method) is generated in the vacuum container. As a result of being filled with hydrogen gas, the evaporation of the low-melting point metal in the contact is suppressed, and the brazing strongly reduces the sealing area, so conventional vacuum brazing in low-pressure hydrogen is much better than the method. Tarozing allows for sealing. Furthermore, since brazing has a stronger reducing effect at 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 the sealing is completed during brazing, the hydrogen partial pressure must be 1 x 10-'Tor.
Heating may be carried out in an inert gas such as nitrogen gas at a temperature of less than For example, an embodiment of the OL invention that makes it possible to simultaneously verify the presence or absence of this leak and its magnitude." Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1st
In the figure, la and 1b are fixed electrodes and movable electrodes,
2 is a bellows, 3a and 3b are a fixed 7-lunge and a movable 7-lunge, 4 is a shield, and 5 is an insulating tube.

All the other members except for the shield 4 are hermetically joined to adjacent members to form a vacuum container, and the materials of their construction are the same as those of the conventional example shown in FIG.

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
1. It is made of a single metal such as tantalum (Ta), niobium (Nb), or zirconium (Zr), or an alloy containing these metals, and is installed at a location where the electric field is relatively low so as not to affect the withstand voltage characteristics of the vacuum breaker.

Further, 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 7 lunge 3a, and the movable 7
The lunge 3b is configured as a hydrogen permeable member. That is, the bellows 2 is made of austenitic stainless steel containing Ir1Ti or /fiTa%Nb, and the fixed 7 flange 3a and the movable 7 flange 3b are made of a copper-Cu alloy or a nickel-N1 alloy containing palladium rd.

These hydrogen permeable members are characterized by a hydrogen permeability that is approximately 10 times greater than conventional austenitic stainless steels and copal (Kouav) alloys.

Similar to the vacuum breaker according to the prior art, the fixed side assembly structure 10. A low-pressure atmospheric gas (hydrogen pressure of about 1
0 Terr) to heat the entire vacuum breaker. In this embodiment, eutectic silver alloy 5 (approximately 72Ag-28Cu) is used as the sealing brazing materials 40a and 40b.

At the same time as heating starts, the hydrogen storage member 6I/
As the temperature rises, the internal hydrogen begins to be released, and almost all of the internal hydrogen is released at the melting point of the eutectic silver solder (approximately 780°C). Temperature rise rate and sealing brazing material 40a
, 40b varies depending on the magnitude of the exhaust conductance determined by the gap between the vacuum chambers 1 and 40b, and in the example, a maximum pressure exceeding about 200 Torr was recorded.

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.

The inside and outside of the vacuum container are cut off by the melting of the solder metal in the sealing part (the melt falls off), but at this time, the hydrogen trapped inside the vacuum is rapidly cooled after the melt falls off. The total pressure inside the vacuum container when the hydrogen storage member 6 starts to absorb it by operation and slowly cools down to room temperature is 5 x 1O-3T.
It was orr.

After that, it is heated again in vacuum at a temperature of 600° C. with a vacuum breaker. The second feature of this invention is the hydrogen permeable member (
2, 3a, 3b) that the hydrogen trapped inside the vacuum vessel is exhausted to the outside of the vacuum vessel? confirmed. In the example, 6 (the total pressure inside the vacuum breaker after heating at 10°C for 2 hours and slowly cooling to room temperature is 3
10-'Torr.

In addition, in the above-mentioned embodiments, vacuum brazing is performed by cooling to K - gigantic room temperature after sealing and then vacuum heating again, but in reality, eutectic silver soldering is performed without cooling to room temperature once. from the melting point (about 78 tl'C) to about 600℃ immediately
By slowly cooling the hydrogen to the hydrogen exhaust temperature, the above-mentioned exhaust time of 2 hours can be further shortened.

Furthermore, in the above-mentioned embodiments, the final brazing sealing was carried out in a high vacuum or in low pressure hydrogen at about 10 Torr, but this was carried out in a hydrogen furnace at about 760 Torr (1 atm). After that, it is also possible to evacuate the hydrogen gas inside the vacuum container in a effluent gas atmosphere or in a vacuum. 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, a good withstand voltage could be obtained even when the fixed seven flange 3a, the movable seven flange 3b, and austenitic stainless steel containing Ta and Nb'i were used.

[Effects of the Invention] As described above, according to the present invention, a hydrogen storage member is provided inside the vacuum container, and since the vacuum container is composed of a metal member and a hydrogen permeable member, a low melting point member is provided inside the vacuum container.・Brazing of a discharge device containing high vapor pressure metal can completely prevent contamination of the sealing part with high vapor pressure metal, resulting in high yield and high sealing reliability, and is suitable for use with beam exhaust tips. This method has the advantage of being able to stably and economically produce a vacuum discharge device that has very low breaking current characteristics.

[Brief explanation of the drawing]

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 breaker. In the figure, la#'j fixed iI! Pole, lb is a movable electrode, 2 is a bellows, 3a#'i is a fixed 7 flange, 3b is a movable #7 flange, 4ti is a shield, 5#- is an insulating cylinder, and 6 is a hydrogen storage member. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] In a vacuum discharge device of a type that has at least one pair of electrodes in a vacuum, a contact portion of the electrodes containing a low melting point metal, and no exhaust tip tube portion, a hydrogen storage member is provided inside the vacuum vessel, and a metal A vacuum discharge device characterized in that a part or all of the metal member of a vacuum container composed of a member and an insulating member is made of a hydrogen permeable member.