CN114242508A

CN114242508A - Vacuum bottle for a switching device

Info

Publication number: CN114242508A
Application number: CN202111025052.0A
Authority: CN
Inventors: A.特里奥宗; D.米兰; P.纽因格; C.普雷夫
Original assignee: Schneider Electric Industries SAS
Current assignee: Schneider Electric Industries SAS
Priority date: 2020-09-09
Filing date: 2021-09-02
Publication date: 2022-03-25
Also published as: FR3113980A1; FR3113980B1; EP3968350A1

Abstract

Vacuum bottle (1) for a switching device, comprising: -a first electrode (5) and a second electrode (6), each comprising a contact portion (8), the second electrode (6) being movable in an axial direction (X) with respect to the first electrode (5) between a closed position and an open position, and-a bellows seal (10) located around a stem (7) of the second electrode (6), the bellows seal (10) being adapted to conduct an electric current between an exterior of the vacuum bottle (1) and the contact portion (8) of the second electrode (6) when the second electrode (6) is in the closed position.

Description

Vacuum bottle for a switching device

Technical Field

The invention relates to a vacuum bottle for a switching device and to a switching device comprising such a vacuum bottle.

The invention is particularly suitable for switches in which the vacuum bottle is located in a branch of the main current line.

Background

Vacuum bottles in circuits that allow the current to be interrupted or re-established alternately by moving two electrodes relative to each other are known.

Thus, current must flow between the electrodes of the vacuum bottle, which requires that current be conducted from the outside of the vacuum bottle to the inside of the vacuum bottle while allowing at least one of the two electrodes to move.

This is relatively difficult to implement.

The present invention therefore aims to propose a switching device comprising a vacuum bottle which is less complex, more compact and less costly to manufacture, allowing the current to be satisfactorily conducted through the vacuum bottle.

Disclosure of Invention

The present invention improves this situation.

It is proposed a vacuum bottle for a switchgear comprising:

-a first electrode and a second electrode, each comprising a contact portion, the second electrode being movable in an axial direction relative to the first electrode between a closed position in which the contact portions of the first and second electrodes are in contact with each other such that an electric current may flow through the vacuum bottle, and an open position in which the contact portions of the first and second electrodes are spaced apart from each other such that the electric current in the vacuum bottle is interrupted, the second electrode comprising a rod extending in the axial direction and terminating at the contact portion, and

a bellows seal located around the stem of the second electrode, adapted to ensure vacuum bottle sealing, while allowing the second electrode to move,

the bellows seal is further adapted to conduct an electrical current between an exterior of the vacuum bottle and a contact portion of the second electrode when the second electrode is in the closed position.

According to one embodiment, the vacuum bottle comprises an electrically conductive element adapted to conduct an electrical current between an exterior of the vacuum bottle and a contact portion of the second electrode when the second electrode is in the closed position, the bellows seal and the electrically conductive element forming two current paths in parallel with each other.

According to another embodiment, the conductive element is a wire or a braided conductor.

According to another embodiment, the rod of the second electrode comprises at least one section made of an electrically insulating material.

According to another embodiment, the section of the rod of the second electrode made of electrically insulating material is located outside the vacuum bottle and/or is surrounded by a bellows seal.

According to another embodiment, the vacuum bottle comprises a lid through which the second electrode is slidably mounted, the bellows seal comprising an end electrically connected to the lid and an end electrically connected to the contact portion of the second electrode.

According to another embodiment, the bellow seal is made of stainless steel, copper and/or copper alloy.

According to another embodiment, the bellows seal comprises a coating made of copper, obtained by electrolysis, plasma spraying or cold spraying.

According to another embodiment, the thickness of the coating made of copper is greater than 0.05 mm, even greater than 0.5 mm.

According to another embodiment, the bellow seal is made of copper plated stainless steel.

According to another aspect, a switching device is proposed, comprising a vacuum bottle according to the invention, in particular for at least one of its electrical phases.

Drawings

Other features, details, and advantages will become apparent upon reading the description provided below and upon reference to the drawings in which:

FIG. 1 is a schematic cross-sectional view of a prior art vacuum bottle according to one embodiment.

FIG. 2 is a schematic cross-sectional view of a prior art vacuum bottle according to another embodiment.

FIG. 3 is a schematic cross-sectional view of a vacuum bottle according to one embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view of a vacuum bottle according to another embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view of a vacuum bottle according to another embodiment of the present invention.

Detailed Description

The figures and the description that follow contain, for the most part, elements that are well-defined in nature. They may thus be used not only to better clarify the disclosure, but also to facilitate its definition where appropriate. In particular, the figures are cross-sectional views. However, it should be understood that many elements, such as the housing, the lid, the bellows seal, or the electrode of the vacuum bottle, have rotational symmetry about a central axis.

Hereinafter, the terms "upper" and "lower" are used only to indicate the relative positions of the elements of the vacuum bottle as shown in the figures. However, it is understood that the vacuum bottle may be installed in the switchgear in any orientation.

Fig. 3 shows a schematic example of a vacuum flask 1 according to the invention according to one embodiment. The vacuum flask 1 is intended for use in a switching device for interrupting a current in an electric circuit, in particular a medium and/or high voltage circuit.

In the following, the terms "medium voltage" and "high voltage" are used in a generally accepted manner, i.e. the term "medium voltage" refers to voltages greater than 1000 volts ac and 1500 volts dc but not exceeding 52000 volts ac and 75000 volts dc, while the term "high voltage" refers to voltages strictly greater than 52000 volts ac and 75000 volts dc.

Hereinafter, the term "switching device" refers to an electrical device for interrupting a current, such as a contactor, a switch, a fuse switch, or a recloser. Other types of switching devices using vacuum bottles are also possible.

The vacuum flask 1 may be used in particular in a switch as described in document EP2182536, in particular in which the vacuum flask is located on a branch of a main current line.

The vacuum flask 1 comprises a substantially cylindrical housing 2 made of an electrically insulating material, preferably ceramic. The housing 2 is closed by two end caps, in particular an upper cap 3 and a lower cap 4. The housing 2 and the upper and

lower covers

3, 4 define an inner switching chamber that can be evacuated.

Hereinafter, the switch chamber refers to the inside of the vacuum bottle 1, and the portion not located in the switch chamber is the outside of the vacuum bottle 1.

The vacuum flask 1 comprises a first electrode 5 and a second electrode 6 at least partially housed inside the vacuum flask 1. The first electrode 5 is stationary, in particular fixed to the lower cap 4, while the second electrode 6 is movably, in particular slidably, mounted so as to slide in the axial direction X inside the vacuum flask 1 by means of the upper cap 3.

Each of the first and second electrodes 5, 6 comprises a rod 7 extending in the axial direction X towards an end 8 forming a contact portion. Thus, the rod 7 of the second electrode 6 is located both inside and outside the vacuum flask 1. The end 8 forming the contact portion may take various shapes and sizes, particularly in the form of a contact ball or pad having a relatively large radius of curvature.

In a known manner, the second electrode 6 can be made to slide by an actuation mechanism not shown in the figures. Thus, the second electrode 6 can be moved between a closed position and an open position. In the figure, only the open position is shown. In the closed position, the contact portion 8 of the first electrode 5 and the contact portion 8 of the second electrode 6 are in contact with each other, so that an electric current can flow through the vacuum flask 1. In the open position, the contact portion 8 of the first electrode 5 and the contact portion 8 of the second electrode 6 are spaced apart from each other, so that the current in the vacuum bottle 1 is interrupted.

The vacuum flask 1 further comprises a bellow seal 10. The bellows seal 10 is comprised of a deformable tubular element. The bellows seal 10 is located around the rod 7 of the second electrode 6 or around at least a part of the rod 7 of the second electrode 6, in particular around a part of the rod 7 of the second electrode 6 located inside the vacuum flask 1. The bellow seal 10 thus comprises an end electrically connected to the upper cover 3 and an end electrically connected to the contact portion 8 of the second electrode 6 or in the vicinity of the contact portion 8 of the second electrode 6. The bellows seal 10 is attached to the upper cover 3 and the second electrode 6 by brazing, for example.

The bellows seal 10, also called sealing bellows, is adapted to ensure the airtightness of the vacuum bottle with respect to the outside (in particular for maintaining the vacuum inside the vacuum bottle 1) while allowing the second electrode 6 to slide.

The vacuum flask 1 may further comprise a dielectric screen 11 placed around the contact portions 8 of the first and second electrodes 5, 6. Other screens not shown are also possible, such as an auxiliary screen surrounding the bellows seal 10.

In fig. 1 and 2, which show the prior art, current is conducted between the first electrode 5 and the second electrode 6 through the rod in the closed position, as indicated by arrow C (showing the flow of current when the second electrode is in the closed position). The rods of the first and second electrodes are thus made of an electrically conductive material.

According to the depiction of fig. 1, the current flows from a current inlet 12 located outside the vacuum bottle. The current is then conducted to the rod of the second electrode through a flexible conductive wire or strip 12, for example made of copper. Thus, the wire allows the current to conduct while allowing the rod of the second electrode to slide in the vacuum bottle.

According to the depiction of fig. 2, the current flows from the current inlet 12 and is conducted to the stem of the second electrode through the conductive seal 15. Thus, the seal 15 allows the current to conduct while allowing the rod of the second electrode to slide in the vacuum bottle.

However, these descriptions are not entirely satisfactory because they require the use of additional components between the current inlet and the vacuum bottle, in particular to pass the current through the second electrode. Now, these components may be the source of failure, particularly if the wires or seals are damaged or worn.

Thus, according to the invention, which is shown more particularly in fig. 3, 4 and 5, the bellows seal 10 is also suitable for conducting an electric current between a current inlet 12 located outside the vacuum flask 1 and the contact portion 8 of the second electrode 6.

The bellows seal 10 is therefore made of an electrically conductive material, for example a metal, in particular stainless steel. In order to ensure a higher electrical conductivity, in particular for stainless steel, the bellows seal 10 may comprise a coating made of another material, such as copper, in particular obtained by electrolysis, plasma spraying or cold spraying. The coating may advantageously have a thickness of more than 0.05 mm, or even more than 0.5 mm.

According to another example, the bellows seal is made of copper plated stainless steel. Such a bellows seal 10 is produced, for example, by roll bonding.

Other embodiments of the bellows seal 10 may be used to ensure satisfactory electrical conductivity, such as it is made of copper or copper alloys, such as, but not limited to, bronze, phosphor bronze, beryllium copper (CuBe), or bronze (CuSn8P or CuSn 9P). Other alloys are also possible.

According to the embodiment of fig. 3, the current is conducted entirely or almost entirely through the bellow seal 10 to the contact portion 8 of the second electrode 6, as indicated by arrow C (showing the flow of current when the second electrode is in the closed position).

According to the present embodiment, the current inlet 12 is electrically connected to, for example, the upper lid 3 of the vacuum bottle 1. The current may then flow from the current inlet 12, through the upper cover 3, through the bellow seal 10, through the contact portion 8 of the second electrode 6, through the first electrode 5, and then through the current outlet 14. The current outlet 14 is located outside the vacuum flask 1, for example in electrical connection with the first electrode 5 of the vacuum flask 1.

According to the embodiment shown more particularly in fig. 4 and 5, the vacuum flask 1 may further comprise an additional electrically conductive element 16 adapted to conduct an electric current between the current inlet 12 located outside the vacuum flask 1 and the contact portion 8 of the second electrode 6.

The conductive element 16 may be, for example, a flexible metal braided conductor or wire made of copper. However, these examples are not limiting and other embodiments are possible.

According to one embodiment, the conductive element 16 may be located in the switching chamber between the bellows seal 10 and the housing 2, as shown in fig. 4. According to another embodiment, the conductive element 16 may be located between the stem 7 of the second electrode 6 and the bellows seal 10, as shown in fig. 5, which further allows the local perturbation of the electric field to be limited.

The electrically conductive element 16 comprises an end portion which is electrically connected to the upper cover 3 or the current inlet 12. The conductive element 16 further comprises an end portion electrically connected to the contact portion 8 of the second electrode 6 or in the vicinity of the contact portion 8 of the second electrode 6, in particular by brazing or welding. The bellows seal 10 and the electrically conductive element 16 thus form two current paths in parallel with each other between the outside of the vacuum bottle and the contact portion 8 of the second electrode 6.

According to the embodiment of fig. 4 and 5, the current is conducted simultaneously by the electrically conductive element 16 and the bellows seal 10, as indicated by arrow C (showing the flow of current when the second electrode is in the closed position).

By "the current is simultaneously conducted by the electrically conductive element 16 and the bellows seal 10" it is understood that the current is distributed between them in a variable proportion when flowing into the vacuum bottle 1, depending on their local resistivity. At least 5%, even 10%, even 20% of the current flows through the bellows seal 10.

The current may then flow from the current inlet 12, through the upper cover 3, then simultaneously through the bellows seal 10 and the conductive element 16, through the contact portion 8 of the second electrode 6, through the first electrode 5, and then through the current outlet 14.

According to the invention, the current does not flow through the rod 7 of the second electrode 6 or only through a section of the rod 7 of the second electrode 6. Thus, all or part of the rod 7 shown hatched in fig. 3, 4 and 5 need not be made of an electrically conductive material. Thus, a portion of the rod 7 can be made of a relatively inexpensive electrically insulating material and can be freed from the dielectric constraints associated with the use of electrically conductive materials liable to locally influence the electric field inside the vacuum bottle. The section made of insulating material is advantageously surrounded by the bellows seal 10 and may be longer or shorter depending on the size of the bellows seal 10 used in the axial direction X.

Furthermore, by virtue of the present invention, no additional components, such as the conductive seals or wires shown in prior art fig. 1 and 2, need to be used. This results in a technical solution comprising fewer components, which is therefore more compact and less costly to manufacture.

Of course, the invention is not limited to the embodiments described above, which are provided as examples only. It includes various modifications, alternative embodiments and other variations which may be contemplated by those skilled in the art within the context of the present invention, particularly any combination of the various modes of operation described above, which may be employed alone or in combination.

Claims

1. Vacuum bottle (1) for a switching device, comprising:

-a first electrode (5) and a second electrode (6), each comprising a contact portion (8), the second electrode (6) being movable in an axial direction (X) relative to the first electrode (5) between a closed position, in which the contact portions (8) of the first and second electrodes (5, 6) are in contact with each other such that an electric current can flow through the vacuum bottle (1), and an open position, in which the contact portions (8) of the first and second electrodes (5, 6) are spaced apart from each other such that the electric current in the vacuum bottle (1) is interrupted, the second electrode (6) comprising a rod (7) extending in the axial direction (X) and terminating at the contact portion (8), and

-a bellows seal (10) around the stem (7) of the second electrode (6) adapted to ensure sealing of the vacuum bottle while allowing the second electrode to move,

characterized in that the bellow seal (10) is further adapted to conduct an electric current between the outside of the vacuum bottle (1) and the contact portion (8) of the second electrode (6) when the second electrode (6) is in the closed position.

2. Vacuum bottle (1) according to claim 1, comprising an electrically conductive element (16) adapted to conduct an electrical current between the outside of the vacuum bottle (1) and the contact portion (8) of the second electrode (6) when the second electrode (6) is in the closed position, the bellow seal (10) and the electrically conductive element (16) forming two current paths in parallel with each other.

3. Vacuum bottle (1) according to claim 2, wherein the conductive element (16) is a wire or a braided conductor.

4. Vacuum bottle (1) according to any of the preceding claims, wherein the rod (7) of the second electrode (6) comprises at least one section made of an electrically insulating material.

5. Vacuum flask (1) according to claim 4, wherein the section of the rod (7) of the second electrode (6) made of electrically insulating material is located outside the vacuum flask (1) and/or surrounded by the bellow seal (10).

6. Vacuum bottle (1) according to any of the preceding claims, comprising a lid (3) by which the second electrode (6) is slidably mounted, the bellow seal (10) comprising an end electrically connected to the lid (3) and an end electrically connected to a contact portion (8) of the second electrode (6).

7. Vacuum bottle (1) according to any of the preceding claims, wherein the bellow seal (10) is made of stainless steel, copper and/or copper alloy.

8. Vacuum bottle (1) according to any of the preceding claims, wherein the bellow seal (10) comprises a coating made of copper obtained by electrolysis, plasma spraying or cold spraying.

9. Vacuum bottle (1) according to claim 8, wherein the thickness of the coating is greater than 0.05 mm, or even greater than 0.5 mm.

10. Vacuum bottle (1) according to any of the preceding claims, wherein the bellow seal (10) is made of copper plated stainless steel.

11. A switching device comprising a vacuum bottle (1) according to any of the preceding claims.