Circuit breaker with vacuum interrupter

Abstract

The invention relates to a circuit breaker (1). The circuit breaker (1) comprises a vacuum arc chamber (3), metal holding means (5, 7) arranged on opposite sides of the vacuum arc chamber (3), a housing (9) having a housing wall (25) which is arranged spaced apart from the outer surfaces (27 to 29) of the vacuum arc chamber (3) and the holding means (5, 7) around the outer surfaces (27 to 29), a plastic cover (11) arranged on partial areas (28.1, 29.1) of the outer surfaces (27) of the vacuum arc chamber (3) and of the holding means (5, 7), and a volume (31) filled with an insulating gas (33) between the plastic cover (11) and the housing wall (25).

Description

TECHNICAL FIELD

[0001] The invention relates to a circuit breaker having a vacuum arc chamber. A vacuum arc chamber is understood here as a vacuum tube which can be evacuated, in which the switching process is carried out. BACKGROUND

[0002] In such a circuit breaker, switch contact elements which can move relative to one another are arranged in the vacuum arc chamber in order to avoid or reduce switching arcs when the switch contact elements are separated. The arc chamber is usually arranged in an insulating gas in a housing, which is compressed by high pressure in order to increase its dielectric strength, in order to be able to arrange metal parts at a smaller distance from one another in the housing and thereby to save construction space. SUMMARY

[0003] The invention is to solve the technical problem of providing an improved circuit breaker having a vacuum arc chamber.

[0004] According to the invention, the above-mentioned technical problem is solved by a circuit breaker having the features of claim 1.

[0005] Advantageous design solutions of the invention are the subject matter of the dependent claims.

[0006] The circuit breaker according to the invention comprises

[0007] - a vacuum arc chamber,

[0008] - holding means of metal arranged on opposite sides of the vacuum arc chamber,

[0009] - a housing having a housing wall which is arranged around the outer surface of the vacuum arc chamber and the holding means at a distance therefrom,

[0010] - a plastic jacket which is arranged on the outer surface of the vacuum arc chamber and on partial areas of the outer surfaces of the two holding means, and

[0011] - a volume filled with insulating gas between the plastic jacket and the housing wall. The housing wall is made of, for example, electrically insulating material, for example of a ceramic material or of a glass fiber reinforced plastic.

[0012] On the one hand, by means of the plastic jacket it is possible to save insulating gas in that the plastic jacket supports the function of the insulating gas. On the other hand, by means of the plastic jacket having a high dielectric strength it is possible to reduce the pressure of the insulating gas, so that with reduced pressure also a sufficient dielectric strength of the system consisting of the plastic jacket and the insulating gas is achieved. Thereby, it is possible to dispense with the use of pressure vessel components in the interrupter unit of the circuit breaker. Additionally, it is possible to omit or to realize significantly more simply a gas monitoring which would otherwise be necessary, since in the event of a leak and thus a pressure drop there is no need to interrupt the function immediately. Furthermore, cost advantages are achieved by simplifying or omitting components and assemblies and by omitting expensive component tests. Furthermore, a lower maintenance outlay is achieved. Furthermore, an important technical advantage is that the instantaneous switching capability of the circuit breaker is ensured even in the event of a sudden pressure drop of the insulating gas.

[0013] Correspondingly, in one design of the application the plastic jacket is made of a plastic having a higher dielectric strength than the insulating gas. The plastic jacket is made of silicone, for example.

[0014] In another design of the application the insulating gas is dehumidified air or carbon dioxide. These insulating gases are environmentally friendly, but their insulating effect is lower than that of sulfur hexafluoride, for example. Therefore, the plastic jacket is advantageous, in particular in the case of the use of these insulating gases to increase the dielectric strength.

[0015] In another design of the application the plastic jacket is a plastic layer which is injection molded or cast on a partial region of the outer surface of the vacuum interrupter and of the outer surface of the holding device. Advantageously, this makes it possible to produce the plastic jacket precisely.

[0016] In an alternative design of the aforementioned design of the application the plastic jacket is a plastic sleeve which is slipped over a partial region of the outer surface of the vacuum interrupter and of the outer surface of the holding device. This makes it possible to manufacture the plastic jacket without the need for tools for injection molding or casting the plastic jacket.

[0017] In another design of the application the plastic jacket has a varying thickness. Thereby it is possible to adapt the thickness of the plastic jacket to the requirements for the dielectric strength locally. For example, the plastic jacket is designed to be thicker in the edge region of the vacuum interrupter or of the holding device than in other regions.

[0018] In another design of the application the circuit breaker has at least one field control element which is arranged between the plastic jacket and a partial region of the outer surface of the vacuum interrupter and / or of the outer surface of the holding device. A field control element is an element which locally changes the electric field strength. By means of the field control element it is possible to avoid particularly high local electric field strengths, in particular advantageously.

[0019] For example, the at least one field control element is made of an electrically conductive plastic, for example of a silicon elastomer filled with carbon black. Such a field control element can advantageously be produced by injection molding or casting, in particular together with a plastic jacket designed as a plastic layer. In the case of a plastic jacket designed as a plastic sleeve, the field control element can be integrated into the plastic sleeve.

[0020] Furthermore, the at least one field control element is preferably arranged on the holding device end of the holding device. Thereby, a high local electric field strength in the region of the holding device end can advantageously be avoided.

[0021] In another design variant of the application, the arc chamber end of the vacuum arc chamber projects into each holding device. Thereby, the production of the plastic jacket in the transition region between the vacuum arc chamber and the holding device is simplified, in particular. BRIEF DESCRIPTION OF DRAWINGS

[0022] The features, aspects and advantages of the application described above and the implementation thereof are more clearly understood in connection with the following description of embodiments, which are described in more detail in conjunction with the drawings. Herein in the drawings:

[0023] Figure 1 A first embodiment of a circuit breaker is shown,

[0024] Figure 2 A second embodiment of a circuit breaker is shown.

[0025] Components that correspond to one another are provided with the same reference signs in the drawings. DETAILED DESCRIPTION

[0026] Figure 1 A sectional view of a first embodiment of a circuit breaker 1 is shown. The circuit breaker 1 comprises, among other things, a vacuum arc chamber 3, tubular metal holding devices 5, 7, a housing 9 and a plastic jacket 11.

[0027] The holding devices 5, 7 are arranged on opposite sides of the vacuum arc chamber 3 and serve, in particular, as a base for the vacuum arc chamber 3. Metal arc chamber ends 13, 15 of the vacuum arc chamber 3 project into each holding device 5, 7. A first switch contact element 17 is arranged on the first holding device 5, which projects into the vacuum arc chamber 3 through a first arc chamber opening in the first arc chamber end 13. A second switch contact element 19 projects into the vacuum arc chamber 3 through a second arc chamber opening in the second arc chamber end 15, which can be moved relative to the first switch contact element 17 by means of a not shown mechanism. The region of the vacuum arc chamber 3 surrounding the switch contact elements 17, 19 has an insulating section 21, 23 made of an electrically insulating material, for example a ceramic material, respectively. The insulating sections 21, 23 are arranged on opposite sides of a central region of the vacuum arc chamber 3 that is metallic.

[0028] The housing 9 comprises a housing wall 25 which is arranged around the outer surface 27, 28, 29 of the vacuum interrupter 3 and of the holding devices 5, 7 spaced apart from the outer surface 27, 28, 29. The housing wall 25 is designed as an insulating tube which is made of an electrically insulating material, for example of a ceramic material or of a glass fiber reinforced plastic, and which is arranged between metal flanges. Thus, the circuit breaker 1 is designed in a so-called live tank construction, in contrast to a so-called dead tank construction with a grounded metal housing.

[0029] The plastic jacket 11 is arranged on partial areas 28.1, 29.1 of the outer surface 27 of the vacuum interrupter 3 and of the outer surfaces 28, 29 of the two holding devices 5, 7. The volume 31 between the plastic jacket 11 and the housing wall 25 is filled with an insulating gas 33, for example with dehumidified air or carbon dioxide.

[0030] The plastic jacket 11 is made of a plastic material having a higher dielectric strength than the insulating gas 33. The plastic jacket 11 is for example made of silicone.

[0031] The plastic jacket 11 has a varying thickness. For example, the plastic jacket 11 is designed thicker in a transition area from the outer surface 27 of the vacuum interrupter 3 to the partial areas 28.1, 29.1 of the outer surfaces 28, 29 of the holding devices 5, 7 than in the areas adjacent thereto, respectively.

[0032] The plastic jacket 11 is for example a plastic layer which is injection molded or cast on the outer surface 27 of the vacuum interrupter 3 and on the partial areas 28.1, 29.1 of the outer surfaces 28, 29 of the holding devices 5, 7. Alternatively, the plastic jacket 11 is a plastic sleeve which is slipped over the outer surface 27 of the vacuum interrupter 3 and over the partial areas 28.1, 29.1 of the outer surfaces 28, 29 of the holding devices 5, 7.

[0033] Figure 2 A sectional view of a second embodiment of the circuit breaker 1 is shown. This embodiment differs from the embodiment shown in Figure 1

[0034] ​Here, the first field control element 35 is arranged on the holding device end 5.1 of the first holding device 5 facing the vacuum interrupter 3, the second field control element 36 is arranged on the end of the first insulation section 21 facing away from the first holding device 5, the third field control element 37 is arranged on the end of the second insulation section 23 facing away from the second holding device 7, and the fourth field control element 38 is arranged on the holding device end 7.1 of the second holding device 7 facing the vacuum interrupter 3. However, the field control elements 35 to 38 can also be arranged on other regions of the outer surfaces 27 to 29.

[0035] The field control elements 35 to 38 are made of, for example, electrically conductive plastic, for example, of a silicon elastomer filled with carbon black, respectively. In the case of a plastic sleeve 11 being a plastic sleeve tube which is sheathed on the outer surface 27 of the vacuum interrupter 3 and on the partial regions 28.1, 29.1 of the outer surfaces 28, 29 of the holding devices 5, 7, the field control elements 35 to 38 can be integrated into the plastic sleeve tube, for example.

[0036] Although the application is illustrated and described in more detail through preferred embodiments in terms of details, it is not restricted to the disclosed examples and other variants can be derived therefrom by a person skilled in the art without departing from the scope of protection of the application.

Claims

1. A circuit breaker (1), comprising - Vacuum interrupter (3). - Tubular metal retaining devices (5, 7) are arranged on opposite sides of the vacuum interrupter (3), and the interrupter ends (13, 15) of the vacuum interrupter (3) extend into each retaining device (5, 7). - A housing (9) having a housing wall (25) arranged around the outer surfaces (27 to 29) of the vacuum interrupter (3) and the retaining devices (5, 7) at a distance from the outer surfaces (27 to 29). - A plastic sleeve (11) is disposed on a portion (28.1, 29.1) of the outer surface (27) of the vacuum interrupter (3) and the outer surfaces (28, 29) of the two retaining devices (5, 7), wherein, The plastic sleeve (11) is made of plastic with a higher dielectric strength than the insulating gas (33), and - The volume (31) between the plastic cover (11) and the shell wall (25) is filled with insulating gas (33). The plastic sleeve (11) is a plastic layer that is injection molded or cast onto a portion (28.1, 29.1) of the outer surface (27) of the vacuum interrupter (3) and the outer surface (28, 29) of the retaining device (5, 7), or the plastic sleeve (11) is a plastic tube that is fitted onto a portion (28.1, 29.1) of the outer surface (27) of the vacuum interrupter (3) and the outer surface (28, 29) of the retaining device (5, 7).

2. The circuit breaker (1) according to claim 1, characterized in that, The plastic cover (11) is made of silicone.

3. The circuit breaker (1) according to claim 1 or 2, characterized in that, The insulating gas (33) is dehumidified air or carbon dioxide.

4. The circuit breaker (1) according to claim 1, characterized in that, The plastic cover (11) has a varying thickness.

5. The circuit breaker (1) according to claim 1, characterized in that, The circuit breaker has at least one field control element (35 to 38) arranged between a portion (28.1, 29.1) of the outer surface (27) of the plastic sleeve (11) and / or the outer surface (28, 29) of the vacuum interrupter (3) and / or the outer surface (28, 29) of the retaining device (5, 7).

6. The circuit breaker (1) according to claim 5, characterized in that, At least one field control element (35 to 38) is made of conductive plastic.

7. The circuit breaker (1) according to claim 5 or 6, characterized in that, At least one field control element (35 to 38) is arranged on the holding end (5.1, 7.1) of the holding device (5, 7).

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