CN114981911A

CN114981911A - Vacuum switch

Info

Publication number: CN114981911A
Application number: CN202080094088.1A
Authority: CN
Inventors: T.海因兹; T.克鲁尔; V.莱曼
Original assignee: Siemens Energy Global GmbH and Co KG
Current assignee: Siemens Energy Global GmbH and Co KG
Priority date: 2020-01-22
Filing date: 2020-12-22
Publication date: 2022-08-30
Also published as: DE102020200738A1; WO2021148217A1; EP4070351A1

Abstract

The invention relates to a vacuum switch (1). The vacuum switch (1) comprises two base elements (3, 5) spaced apart from each other, a vacuum switching tube (7) arranged between the base elements (3, 5), and a plurality of mechanically rigid carrier elements (9) each made of an insulating material. Each support element (9) is connected to both base elements (3, 5) and surrounds the vacuum interrupter (7) partially circumferentially and without contact. The support elements (9) are arranged spaced apart from one another around the vacuum interrupter (7) and are surrounded by an electrically non-conductive elastomer (13) which fills the intermediate space between the support elements (9) and the vacuum interrupter (7).

Description

Vacuum switch

Technical Field

The invention relates to a vacuum switch having two base elements spaced apart from one another and a vacuum switching tube arranged between the base elements.

Background

Such vacuum switches are circuit breakers in which switch contact elements which are movable relative to one another are arranged in a vacuum switching tube in order to avoid or reduce switching arcs when the switch contact elements are separated. In the known design of vacuum switches, the vacuum interrupter is arranged in an electrically insulating housing in an insulating gas which is compressed by a high voltage in order to increase its dielectric strength, in order to be able to arrange metal parts in the housing at a smaller distance from one another and thus to save installation space. Such vacuum switches are relatively complex and expensive due to the insulating gas under pressure and, moreover, do not function properly in the event of a pressure drop. In a further embodiment of the vacuum circuit breaker, the vacuum circuit breaker tube is alternatively or additionally coated with a plastic, which replaces or supplements the dielectric function of the insulating gas. However, in this embodiment, forces, in particular forces caused by temperature changes, are transmitted from the plastic to the housing of the vacuum interrupter, so that this embodiment is suitable only for relatively small vacuum interrupters, in which the forces occurring are so small that they do not damage the vacuum interrupter.

Disclosure of Invention

The object of the present invention is to provide a vacuum switch which is improved, in particular with regard to its functional reliability and the reduction of the forces acting on the vacuum switch tube.

According to the invention, the above-mentioned object is achieved by a vacuum switch having the features of claim 1.

Advantageous embodiments of the invention are the subject matter of the dependent claims.

The vacuum circuit breaker according to the invention comprises two base elements spaced apart from one another, a vacuum circuit breaker tube arranged between the base elements, and a plurality of mechanically rigid support elements, each made of an insulating material. Each carrying element is connected to two base elements and surrounds the vacuum interrupter partially circumferentially and without contact. The carrier elements are arranged spaced apart from one another around the vacuum interrupter and are surrounded by an electrically non-conductive elastomer, which fills the intermediate spaces between the carrier elements and the vacuum interrupter.

The invention combines a multi-part support structure of a vacuum switch, which is formed by a support element, with an electrically non-conductive elastomer surrounding the support element. The carrier element imparts mechanical strength to the vacuum switch by virtue of it connecting the base elements of the vacuum switch to one another. In addition, the support element contributes to the dielectric strength, which in other embodiments of the vacuum circuit breaker is achieved by means of an insulating gas under pressure and/or a plastic material covering the vacuum circuit breaker tubes. Since the carrier element surrounds the vacuum interrupter without contact and at a distance from one another and is connected to the vacuum interrupter only by the elastomer, little force is transmitted from the carrier element to the vacuum interrupter. Although temperature changes can result in changes in the volume of the elastomer. However, this volume change is transferred outward via the intermediate spaces between the support elements, so that only slight stresses occur at the vacuum interrupter. In a figurative sense, the elastomer can "breathe" through the intermediate space between the load bearing elements.

By the vacuum interrupter having a plurality of carrier elements distributed around the vacuum interrupter, the carrier elements can also be mounted individually and the shape of the carrier elements can be adapted to the shape of the vacuum interrupter, so that each carrier element has a substantially constant distance from the vacuum interrupter over its entire length. In contrast, the one-piece, tubular carrier element must have a minimum inner diameter which is greater than the maximum outer diameter of the vacuum interrupter tube in order to be able to fit the carrier element around the vacuum interrupter tube. In this way, in the case of vacuum interrupters with a varying outer diameter, the distance of the carrier element from the vacuum interrupter will vary along the vacuum interrupter, so that the wall thickness and therefore the mechanical and dielectric strength of the jacket formed by the carrier element and the elastomer body around the vacuum interrupter will vary. Furthermore, due to the varying distance, more elastomer will be required to fill the intermediate space between the vacuum interrupter tube and the carrier element, which may significantly increase the cost of the vacuum interrupter, as suitable elastomers are typically relatively expensive.

The invention thus makes it possible to realize a vacuum circuit breaker without insulating gas, in which little of the forces of the support structure are transmitted to the vacuum interrupter, so that the vacuum circuit breaker is also suitable for large vacuum interrupters. By means of the design without insulating gas, in particular, components for gas monitoring, pressure sealing systems and pressure vessel parts are omitted. The vacuum switch according to the invention can also be designed in a simple manner for different requirements by a corresponding design of the carrier element in particular in order to achieve a specific shielding geometry, creepage path, thickness and/or breakdown distance, for example.

In one embodiment of the vacuum circuit breaker, at least one base element has a fastening flange, which is connected to the carrier element. This enables a simple and suitable connection of the carrier element to the base element.

In a further embodiment of the vacuum switch, the carrier element is connected to the base element by a screw connection and/or an adhesive connection. The threaded connection can be realized, for example, by a threaded bushing introduced into the carrier element, and the threaded connection enables a detachable connection of the carrier element to the base element.

In a further embodiment of the vacuum interrupter, the vacuum interrupter is connected to the first base element and the movable switching contact element of the vacuum interrupter protrudes into the second base element. The first base element thus carries the vacuum switch. For example, the vacuum interrupter can be arranged at the first base element via a fixed (immovable) switching contact element, which has an end that is led out of the vacuum interrupter and is connected to the first base element. In the second base element, for example, components of a mechanism for moving the movable switching contact element can be arranged.

In a further embodiment of the vacuum switch, the first base element has a shielding region, which encloses an end region of the vacuum interrupter facing the first base element in a hood-like manner, and a hollow-cylindrical region or a solid-cylindrical region in the form of a screw, which adjoins the shielding region away from the vacuum interrupter. In a further embodiment of the vacuum switch, the second base element is designed essentially as a hollow cylinder into which an end region of the vacuum switch tube facing the second base element projects. The base element can thereby contribute to shielding the electric field at the end region of the vacuum interrupter.

In a further embodiment of the vacuum switch, the vacuum switch has an outer surface formed from an elastomer, which extends around the carrier element. The outer surface formed by the elastomer may in particular have a plurality of hood-shaped surface regions which extend concentrically around the carrier element. In this embodiment of the vacuum circuit breaker, the elastomer is also advantageously used for forming the outer surface of the vacuum circuit breaker, in particular for forming an insulating shield for extending the creepage path of the leakage current along the outer surface of the vacuum circuit breaker.

In a further embodiment of the vacuum switch, the elastomer is a silicone elastomer. Silicone elastomers are resistant to Ultraviolet (UV) light and are therefore particularly useful for forming the outer surface of vacuum switches.

In a further embodiment of the vacuum circuit breaker, each support element is made of plastic or a fiber-plastic composite or ceramic material. Plastics and fibre-plastic composites are preferred materials for the manufacture of the load-bearing element, since a load-bearing element having a suitable shape and the desired mechanical and dielectric properties can be produced relatively simply using plastics and fibre-plastic composites. Ceramic materials may also be used, but are relatively brittle and heavy and are therefore generally less preferred.

In a further embodiment of the vacuum switch, at least one carrier element has at least one recess, which is filled with an elastomer. The recesses in the carrier elements serve to shift the volume change of the elastomer body outwards, as do the intermediate spaces between the carrier elements, in order to avoid or reduce stresses at the vacuum interrupter.

In a further embodiment of the vacuum switch, the at least one recess in the carrier element has an oval shape. Here, the oval shape also includes a shape having a straight edge section by section, for example, a "racetrack shape". By having an oval-shaped recess, the dielectrically disadvantageous corners of the recess are avoided and a suitable compromise between the mechanical strength and the dielectric strength of the carrier element is achieved.

In a further embodiment of the vacuum switch, the at least one recess in the carrier element is formed by a recess in the base body of the carrier element, in which recess at least one filling body of the carrier element is arranged, which filling body is connected to the base body by means of an elastic web. The elasticity of the web enables the filling body to move relative to the base body. The filler body embedded in the elastomer can thus be moved relative to the base body when the volume of the elastomer changes, in particular as a function of temperature. Thus, the elastomer can "breathe" through the grooves in the matrix despite the filler. The elastomer is saved by the filling body, as a result of which the production costs for the vacuum switch can be reduced, since the material from which the carrier element is made is generally less expensive than the elastomer.

In a further embodiment of the vacuum switch, the carrier element has a substantially constant wall thickness. This advantageously avoids load-critical regions of the carrier element with a very small wall thickness and a varying dielectric strength of the carrier element. The regions of the support element which are subjected to particularly strong local loads can of course have a greater wall thickness than the remaining regions.

In a further embodiment of the vacuum circuit breaker, each support element has a shape corresponding to the vacuum circuit breaker tube, so that the support element has a substantially constant distance from the vacuum circuit breaker tube. This advantageously makes it possible to achieve a uniform wall thickness and thus a uniform mechanical and dielectric strength of the casing formed from the carrier element and the elastomer around the vacuum interrupter tube. Furthermore, by minimizing the distance between the carrier element and the vacuum interrupter tube and thus the intermediate space filled with elastomer, the amount of elastomer required for manufacturing the vacuum interrupter can advantageously be minimized.

In the method according to the invention for producing a vacuum switch according to the invention, the carrier element is first assembled around the vacuum switch tube and subsequently cast together with the elastomer in a casting mold.

In this way, the elastomer can be applied in a simple manner after the other components of the vacuum switch have been preassembled in the mold into which the preassembled vacuum switch is introduced.

Drawings

The above described features, characteristics and advantages of the present invention and the manner of attaining them will become more apparent and the invention will be better understood by reference to the following description of embodiments taken in conjunction with the accompanying drawings. Herein in the drawings:

figure 1 shows a cross-sectional view of a first embodiment of a vacuum switch,

figure 2 shows the vacuum switch of figure 1 in a pre-assembled state without the elastomer,

figure 3 shows a perspective view of the carrying element of the vacuum switch shown in figure 1,

figure 4 shows a cross-sectional view of a second embodiment of a vacuum switch,

figure 5 shows the vacuum switch of figure 4 in a pre-assembled state without the elastomer,

figure 6 shows a perspective view of the carrying element of the vacuum switch shown in figure 4,

figure 7 shows a cross-sectional view of a third embodiment of a vacuum switch,

figure 8 shows a cross-sectional view of a fourth embodiment of a vacuum switch,

figure 9 shows a cross-sectional view of a fifth embodiment of a vacuum switch,

figure 10 shows the vacuum switch of figure 9 in a pre-assembled state without the elastomer,

figure 11 shows a cross-sectional view of a sixth embodiment of a vacuum switch,

fig. 12 shows the vacuum switch of fig. 11 in a pre-assembled state without the elastomer.

Parts corresponding to each other are provided with the same reference numerals in the figures.

Detailed Description

Fig. 1 shows a cross-sectional view of a first embodiment of a vacuum switch 1. The vacuum switch 1 comprises two base elements 3, 5 spaced apart from one another, a vacuum switch tube 7 arranged between the base elements 3, 5 and two mechanically rigid carrier elements 9, which are connected to the two base elements 3, 5, respectively. Each carrier element 9 surrounds the vacuum interrupter 7 approximately half-circumferentially and without contact and is made of an insulating material. The support elements 9 are arranged spaced apart from one another around the vacuum interrupter 7, so that they enclose the vacuum interrupter 7 in a tubular manner together with the gaps 10 extending between them. The carrier elements 9 are surrounded by an electrically non-conductive elastomer 13, which fills the intermediate spaces between the carrier elements 9, which form the gaps 10, and the intermediate spaces between the carrier elements 9 and the vacuum interrupter tube 7, and forms the outer surface 15 of the vacuum interrupter 1, which extends around the carrier elements 9.

Fig. 2 shows the vacuum switch 1 shown in fig. 1 in a preassembled state without the elastomer body 13.

Fig. 3 shows a perspective view of the carrier element 9 of the vacuum switch 1 shown in fig. 1.

The vacuum interrupter 7 has a metallic central region 17, two

metallic end regions

19, 21 and two insulating

regions

23, 25. The intermediate region 17 has a larger diameter than the

end regions

19, 21 and the insulating

regions

23, 25 and is arranged between the insulating

regions

23, 25. The insulating

regions

23, 25 are each made of a non-conductive material. The first end region 19 projects into the first base element 3 and adjoins the first insulating region 23. The second end region 21 projects into the second base element 5 and adjoins a second insulation region 23.

Two electrically conductive

switching contact elements

27, 29 are arranged in the vacuum interrupter 7. The first switching contact element 27 is fixedly connected to the first end region 19 of the vacuum interrupter 7. The end of the first switching contact element 27 which leads out of the vacuum interrupter 7 is connected to the first base element 3, for example, by a screw connection (not shown). The vacuum interrupter 7 is thereby connected to the first base element 3. The second switch contact element 29 can be moved by means of a mechanism, not shown, relative to the first switch contact element 27 between a first switch position, in which the

switch contact elements

27, 29 are in contact, and a second switch position, shown in fig. 1, in which the

switch contact elements

27, 29 are spaced apart from one another. One end of the second switching contact element 29 leads out of the vacuum interrupter 7 through an opening in the second end region 21.

The base elements 3, 5 are each made of metal (e.g. aluminium) or an alloy. Each base element 3, 5 is substantially designed as a hollow cylinder, wherein the end of the first base element 3 facing the vacuum interrupter 7 is designed as a shielding region 31 which closes off the hollow-cylinder region 39 on the vacuum interrupter side and encloses the first end region 19 of the vacuum interrupter 7 in a hood-like manner. The end of the first switching contact element 27 which leads out of the vacuum interrupter 7 is arranged centrally at the shielding region 31. Furthermore, each base element 3, 5 has an outwardly projecting

fastening flange

33, 35, to which the ends of the two carrier elements 9 are fastened by screwing. For this purpose, threaded bushings 12 are introduced (for example cast) into the ends of the carrier element 9 to accommodate the threaded elements, respectively. The fastening flange 33 of the first base element 3 is arranged in the vicinity of the first end region 19 of the vacuum interrupter 7, and the fastening flange 35 of the second base element 5 is arranged in the vicinity of the second end region 21 of the vacuum interrupter 7.

The two support elements 9 extend between the

fastening flanges

33, 35 along the vacuum interrupter tube 7. Each carrier element 9 has a shape corresponding to the vacuum interrupter 7, so that the carrier element 9 has a substantially constant distance from the vacuum interrupter 7. Each support element 9 is widened, in particular, in an intermediate section 9.1 corresponding to the intermediate region 17 of the vacuum interrupter 7, relative to side sections 9.2, 9.3 adjoining the intermediate section 9.1 on both sides, which correspond to the

insulation regions

23, 25 of the vacuum interrupter 7. The end sections 9.4, 9.5 of the carrier element 9, into which the threaded bushing 12 is introduced and which for this purpose have a greater wall thickness than the middle section 9.1 and the side sections 9.2, 9.3, adjoin each side section 9.2, 9.3. The carrier element 9 is made, for example, of plastic, a fiber-plastic composite material or a ceramic material.

The elastomer 13 is, for example, a silicone elastomer. The outer surface 15 formed by the elastomer body 13 has a plurality of surface regions 37 which are hood-shaped and extend concentrically around the carrier element 9.

To produce the vacuum circuit breaker 1, the carrier element 9 is first fitted around the vacuum circuit breaker tube 7 and connected to the base elements 3, 5. Fig. 2 shows the vacuum switch 1 preassembled in this way. The preassembled vacuum circuit breaker 1 is subsequently cast together with the elastomer 13 in a casting mold, wherein the intermediate space between the carrier elements 9 and the vacuum circuit breaker tube 7 is filled with the elastomer 13 and forms the outer surface 15 of the vacuum circuit breaker 1.

Fig. 4 shows a sectional view of a second embodiment of the vacuum switch 1. This embodiment differs from the first embodiment shown in fig. 1 only in that each carrier element 9 has a plurality of recesses 11. In this case, the recesses 11 are arranged in the middle section 9.1 and the two side sections 9.2, 9.3 of the carrier element 9, respectively. The recesses 11 each have an oval shape with a piecewise rectilinear edge and are each filled with an elastic body 13.

Fig. 5 shows the vacuum switch 1 shown in fig. 4 in a preassembled state without the elastomer body 13, analogously to fig. 2.

Fig. 6 shows a perspective view of the carrier element 9 of the vacuum switch 1 shown in fig. 4.

Fig. 7 shows a sectional view of a third embodiment of the vacuum switch 1. This embodiment differs from the first embodiment shown in fig. 1 by the design of the first base element 3. Instead of the hollow-cylindrical region 39, a solid cylindrical region 41 in the form of a screw, which has a smaller diameter than the shielding region 31, adjoins the shielding region 31 of the first base element 3 away from the vacuum interrupter. The solid cylindrical region 41 can comprise at least one screw extending through it in order to fasten the first switch contact element 27 at the first base element 3. In other words, the first base element 3 can have a base body through which at least one screw is guided in the longitudinal direction into the first switch contact element 27. In this case, the base body in the solid cylindrical region 41 is therefore not designed as a completely solid cylinder, but rather has at least one hole for a screw. However, the base body together with the at least one screw essentially forms a solid cylinder in the solid cylinder region 41. However, the first switch contact element 27 can also be connected to the first base element 3 in other ways, for example by welding or shrinking. In this case, the solid cylindrical region 41 can be designed as a one-piece, completely solid cylinder. Compared to the first exemplary embodiment shown in fig. 1, the smaller diameter of the first base element 3 in the solid cylindrical region 41 saves material for the first base element 3 and for the elastomer body 13 and reduces the weight of the vacuum switch 1.

Fig. 8 shows a sectional view of a fourth embodiment of the vacuum switch 1. This embodiment differs from the embodiment shown in fig. 7 in that the shielding region 31 of the first base element 3 projects obliquely from the solid cylindrical region 41 toward the vacuum interrupter 7 and has a central region 43, which extends the solid cylindrical region 41 on the vacuum interrupter side and at which the end of the first switching contact element 27 that emerges from the vacuum interrupter 7 is arranged. As in the exemplary embodiment shown in fig. 7, the solid cylindrical region 41 can comprise at least one screw extending through it in order to fasten the first switch contact element 27 to the first base element 3. In addition, in contrast to the exemplary embodiment shown in fig. 7, the support elements 9 each extend as far as the end of the first base element 3 facing away from the vacuum interrupter.

Fig. 9 and 10 show a fifth exemplary embodiment of a vacuum switch 1. This embodiment differs from the embodiment shown in fig. 4 to 6 in the design of the support element 9. The carrier element 9 is not widened in its middle section 9.1 relative to its side sections 9.2, 9.3, but rather has a constant outer diameter over its entire length. Furthermore, each carrier element 9 has only two recesses 11 arranged one behind the other in the longitudinal direction. Fig. 9 shows a sectional view of the vacuum switch 1. Fig. 10 shows the vacuum switch 1 shown in fig. 9 in a preassembled state without the elastomer body 13, similarly to fig. 5.

Fig. 11 and 12 show a sixth embodiment of the vacuum switch 1. This embodiment differs from the embodiment shown in fig. 9 and 10 in the design of the recess 11 in the carrier element 9. Each recess 11 in the carrier element 9 is formed by an oval recess 11.1 in the base body 9.6 of the carrier element 9, in which recess at least one filling body 9.7 of the carrier element 9 is arranged, which filling body is connected to the base body 9.6 by means of a web 9.8. Each web 9.8 is narrow and is thus designed elastically so that the filling body 9.7 connected to the base body 9.6 via the web can be moved relative to the base body 9.6. The filler body 9.7 embedded in the elastomer body 13 can thus be moved relative to the base body 9.6 when the volume of the elastomer body 13 changes, in particular as a function of temperature. The elastomer 13 is saved by the filling body 9.7, as a result of which the production costs for the vacuum circuit breaker 1 can be reduced, since the material from which the support element 9 is made is generally less expensive than the elastomer 13. Fig. 11 shows a sectional view of the vacuum switch 1. Fig. 12 shows the vacuum switch 1 shown in fig. 11 in a preassembled state without the elastomer body 13, similarly to fig. 5.

The features of the embodiments of the vacuum switch 1 shown in fig. 1 to 12 can be combined with one another into further embodiments. The exemplary embodiments shown in fig. 7 and 8 can in particular be modified in such a way that their carrier element 9 has a recess 11 similar to the carrier element 9 shown in fig. 5, 10 or 12. Furthermore, the embodiment shown in fig. 9 and 10 can be modified such that the carrier element 9 is designed without the recess 11.

Although the invention has been illustrated and described in more detail in the context of preferred embodiments, the invention is not limited to the examples disclosed and other variants can be derived therefrom by those skilled in the art without departing from the scope of protection of the invention.

Claims

1. A vacuum switch (1) comprises

Two base elements (3, 5) spaced apart from each other,

-a vacuum switching tube (7) arranged between the base elements (3, 5), and

-a plurality of mechanically rigid carrier elements (9), wherein

-each carrying element (9) is connected with two base elements (3, 5) and surrounds the vacuum switching tube (7) partially circumferentially and without contact, and is made of an insulating material, and

-the carrier elements (9) are arranged spaced apart from one another around the vacuum interrupter (7) and are surrounded by an electrically non-conductive elastomer (13) which fills the intermediate spaces between the carrier elements (9) and the vacuum interrupter (7).

2. Vacuum switch (1) according to claim 1,

wherein at least one base element (3, 5) has a fastening flange (33, 35) which is connected to the carrier element (9).

3. Vacuum switch (1) according to claim 1 or 2,

wherein each carrying element (9) is connected with the base element (3, 5) by a threaded connection and/or an adhesive connection.

4. Vacuum switch (1) according to one of the preceding claims,

wherein the vacuum interrupter (7) is connected to the first base element (3) and a movable switching contact element (29) of the vacuum interrupter (7) protrudes into the second base element (5).

5. The vacuum switch (1) according to claim 4,

wherein the first base element (3) has a shielding region (31) which surrounds an end region (19) of the vacuum interrupter (7) facing the first base element (3) in a hood-like manner and has a hollow-cylindrical region (39) or a solid-cylindrical bolt-like region (41) which adjoins the shielding region (31) away from the vacuum interrupter.

6. Vacuum switch (1) according to claim 4 or 5,

wherein the second base element (5) is essentially designed as a hollow cylinder into which an end region (21) of the vacuum interrupter (7) facing the second base element (5) projects.

7. Vacuum switch (1) according to one of the preceding claims,

the vacuum switch has an outer surface (15) formed by the elastomer (13), which extends around the carrier element (9).

8. The vacuum switch (1) according to claim 7,

wherein the outer surface (15) formed by the elastomer body (13) has a plurality of hood-shaped surface regions (37) which extend concentrically around the carrier element (9).

9. Vacuum switch (1) according to one of the preceding claims,

wherein the elastomer (13) is a silicone elastomer.

10. Vacuum switch (1) according to one of the preceding claims,

wherein each carrying element (9) is made of a plastic or a fiber-plastic composite or a ceramic material.

11. Vacuum switch (1) according to one of the preceding claims,

wherein at least one carrier element (9) has at least one recess (11) which is filled with the elastomer (13).

12. The vacuum switch (1) according to claim 11,

wherein at least one recess (11) in the carrier element (9) has an oval shape.

13. Vacuum switch (1) according to claim 11 or 12,

wherein at least one recess (11) in the carrier element (9) is formed by a recess (11.1) in a base body (9.6) of the carrier element (9), in which recess at least one filling body (9.7) of the carrier element (9) is arranged, which filling body is connected to the base body (9.6) by means of a resilient web (9.8).

14. Vacuum switch (1) according to one of the preceding claims,

wherein each carrying element (9) has a shape corresponding to the vacuum switching tube (7) such that the carrying element (9) has a substantially constant distance from the vacuum switching tube (7).

15. Method for manufacturing a vacuum switch (1) according to one of the preceding claims,

wherein the support element (9) is fitted around the vacuum interrupter (7) and subsequently cast together with the elastomer (13) in a casting mould.