JPH04351819A - Vacuum valve - Google Patents

Abstract

PURPOSE:To prevent deterioration in the degree of vacuum in a vacuum vessel so as to obtain a high-reliability vacuum valve even if gas is discharged due to a vacuum arc generated at the time of shutting off a current. CONSTITUTION:A thin film made of a Ti material is formed on at least either the inside face 15 of an arc shield 10 surrounding a pair of electrodes 5, 6 in a vacuum vessel 4 or the peripheral part of each of the electrodes 5, 6.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum valve that prevents deterioration of the degree of vacuum.

0002

2. Description of the Related Art FIG. 3 shows a configuration diagram of a conventional vacuum valve for interrupting large currents. In FIG. 3, the openings at both ends of the insulating cylinder 1 are hermetically sealed with end plates 2 and 3 to form a vacuum container 4,
A pair of electrodes 5 and 6 that can be freely moved into and out of contact with each other are arranged inside this. The fixed current-carrying shaft 7 of the electrode 5 is fixedly attached to the end plate 2,
A movable energizing shaft 8 of the electrode 6 is movably attached to the end plate 3 via a bellows 9. Further, an arc shield 10 surrounding the electrodes 5 and 6 is attached to the insulating cylinder 1, and a bellows cover 11 is attached to the current-carrying shaft 8. Further, in the movable side electrode 6, a vacuum arc is ignited between the contacts 12 and 13 which are opened by an operation mechanism (not shown) when the current is cut off.

0003

Problems to be Solved by the Invention The vacuum valve is required to maintain the degree of vacuum within the vacuum container for a long period of time. However, the vacuum arc that occurs when the current is cut off has a high temperature of several thousand degrees, so if the vacuum arc touches the metal components inside the vacuum valve, gas may be released. This released gas accumulates within the vacuum valve, and as the current is cut off, the degree of vacuum within the vacuum valve gradually deteriorates. Recently, especially as vacuum valves have become smaller, the influence of released gas has become relatively large. An object of the present invention is to provide a vacuum valve that prevents deterioration of the degree of vacuum and has excellent current interrupting performance and high reliability. [Structure of the invention]

0004

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a pair of electrodes which are disposed in a vacuum container which is formed by airtightly sealing both ends of an insulating cylinder with end plates. A vacuum valve having a shield disposed to surround the pair of electrodes is constructed such that the inner surface of the shield is covered with a Ti material thin film or at least one of the electrode surfaces is covered with a Ti material thin film.

[0005]

[Function] In this configuration, the inner surface of the shield surrounding the pair of electrodes that can be freely approached and separated is covered with a Ti thin film.
Even if gas is released due to the vacuum arc generated when the electrodes are opened, it is absorbed by the Ti material thin film on the inner surface of the shield, and deterioration of the vacuum degree can be prevented.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of the vacuum valve of the present invention. In FIG. 1, a vacuum container 4 is formed by airtightly sealing the openings at both ends of an insulating cylinder 1 with end plates 2 and 3, and a pair of electrodes 5 and 6 which can be freely connected and separated are arranged inside the vacuum container 4. . The fixed energizing shaft 7 of the electrode 5 is fixedly attached to the end plate 2, and the movable energizing shaft 8 of the electrode 6 is movably attached to the end plate 3 via a bellows 9, so that an arc shield is formed around the electrodes 5 and 6. 10
is attached to the insulating cylinder 1, and the bellows cover 11 is attached to the current-carrying shaft 8. A thin film of metal Ti is attached to the inner surface 15 of the arc shield 10.

Next, the operation of this embodiment will be explained. When energized, the electrodes are brought into contact with each other by an operating mechanism (not shown), and the energizing current flows through the energizing shaft 7 , the electrode 5 , the contact 12 , the contact 13 , the electrode 6 , and the energizing shaft 8 in this order. When the current is cut off, the contacts 12 and 13 are separated by the action of an external operating mechanism and an arc is generated. At this time, the arc between the electrodes may slightly protrude from the space between the electrodes 5 and 6, depending on conditions such as the cutoff phase. This protruding arc may reach the arc shield 10 as it is, and in this case, internal gas may be released from the base metal of the arc shield 10. Even in this case, since there is a thin film of metallic Ti on the arc shield inner surface 15, the heat input from this arc evaporates the Ti and scatters Ti over a wide range of the arc shield inner surface 15, and this scattered Ti vapor remains for a long time. Since it has an adsorption effect on gas molecules, the gas emitted by the arc is immediately adsorbed. In addition, compared to the area where gas is released due to exposure to the arc, the Ti formed here has a high adsorption rate.
Since the area of the thin film is large, the total amount of gas adsorbed is larger than the released gas, and the effect of maintaining the degree of vacuum can be maintained for a long period of time. This Ti thin film has the same effect even if it is a vapor deposited film.

In FIG. 2 showing another embodiment, the electrodes are brought into contact with each other by an operation mechanism (not shown) when energized, and the energizing current is applied to the energizing shaft 7, the electrode 5, the contact 12, and the contact. The terminal 13, the electrode 6, and the current-carrying shaft 8 are connected in this order. When the current is cut off, the contacts 12 and 13 are separated by the action of an external operating mechanism and an arc is generated. At this time,
Normally, the arc between the electrodes is ignited between the contacts 12 and 13. Depending on conditions such as the cutoff phase and current value, when the current value is large, a portion of the arc between the electrodes moves to the periphery of the electrodes and ignites the Ti metal parts 16, 16'. This usually occurs at relatively large current values. Normally, when the current value is large, the electrodes and other components are exposed to the arc, and the gas released is more severe. When an arc is struck on the Ti portions 16, 16', the Ti causes evaporation and scatters Ti vapor around it. This Ti vapor ultimately accumulates on the arc shield inner surface 15 and the surfaces of the electrodes 5 and 6, forming a thin film with a high gas adsorption rate. With the above, the same effects as the vacuum valve shown in FIG. 1 can be obtained.

[0009]

As described above, the present invention provides a coating of Ti, which has a good gas adsorption effect, on the inner surface of the shield or around the electrode, which is arranged so as to surround a pair of electrodes that can be freely moved in and out of the vacuum container.
By forming a thin film of Ti material, the thin film of Ti material absorbs the gas emitted by the vacuum arc that occurs when the current is cut off, preventing deterioration of the vacuum level and obtaining a highly reliable vacuum valve with excellent cutoff performance. can.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a vacuum valve of the present invention.

FIG. 2 is a sectional view of a vacuum valve showing another embodiment of the present invention.

FIG. 3 is a sectional view of a conventional vacuum valve.

[Explanation of symbols]

10... Arc shield, 12, 13... Contact, 15... Shield inner surface, 16... Ti
Department.

Claims (1)

[Claims] [Claim 1] A vacuum container formed by airtightly sealing both ends of an insulating cylinder with end plates, and a pair of electrodes disposed so as to be able to come into contact with and be separated from the vacuum container, and the electrodes are arranged so as to surround the pair of electrodes. 1. A vacuum valve having a shield, characterized in that at least one of the inner surface of the shield or the peripheral part of the electrode is covered with a thin film of Ti material.