Electrical interrupter switching element having passive interruption tripping, in particular for interrupting high currents at high voltages

Abstract

An example interruption switch includes a casing surrounding a contact unit, defining a current path through the switch, which has two connection contacts, a separation region and a sabot. A current supplied to the contact unit may be interrupted via the one of the connection contacts and discharged via the other connection contact. At least one chamber in the switch, delimited by the separation region, is substantially filled with a vaporizable medium in contact with the separation region. The separation region is separable into at least two parts through the supplied current when a threshold amperage is exceeded. An electric arc forming between the two parts at least partially vaporizes the vaporizable medium, and a gas pressure to which the sabot is exposed forms. The sabot moves, in the casing, from a starting to an end position, achieving an insulation spacing between the connection contacts.

Claims

1. An interruption switch for interrupting high currents at high voltages comprises: a casing, which surrounds a contact unit defining a current path through the interruption switch, wherein the contact unit has a first connection contact and a second connection contact, a separation region and a sabot, wherein the contact unit is formed such that a current to be interrupted is supplied to it via the first connection contact and discharged therefrom via the second connection contact, or vice versa, at least one chamber in the interruption switch, at least partially delimited by the separation region, is filled with a vaporizable medium, such that the separation region is in contact with the vaporizable medium, and wherein the separation region, the sabot and the vaporizable medium are formed such that the separation region is separable into at least two parts through a supplied current when a threshold amperage is exceeded, wherein an electric arc forming between the two parts of the separation region vaporizes the vaporizable medium, such that a gas pressure to which the sabot is exposed forms, wherein the sabot in the casing is moved in a movement direction from a starting position into an end position, wherein in the end position of the sabot an insulation spacing is achieved between the first and the second connection contact.

2. The interruption switch according to claim 1, wherein the interruption switch does not contain any activatable means for separating the separation region.

3. The interruption switch according to claim 1, wherein the separation region is formed of a metal configured to form an alloy with a soft solder material.

4. The interruption switch according to claim 1, wherein a substance for capturing or oxidizing elemental carbon is a component of the vaporizable medium.

5. The interruption switch according to claim 1, wherein a substance which reacts exothermically during the formation of the electric arc is a component of the vaporizable medium.

6. The interruption switch according to claim 1, wherein a substance which increases the capacity of the vaporizable medium to absorb mechanical energy is a component of the vaporizable medium.

7. The interruption switch according to claim 1, wherein the separation region includes predetermined breaking points in the form of one or more of narrowings, notches, holes and cross-sectional jumps.

8. The interruption switch according to claim 1, wherein the separation region separates the at least one chamber from a further chamber which surrounds the separation region in a hollow manner.

9. The interruption switch according to claim 8, wherein both the at least one chamber and the further chamber are filled with the vaporizable medium.

10. The interruption switch according to claim 1, wherein the contact unit has an upsetting region.

11. The interruption switch according to claim 10, wherein the upsetting region includes a respective material and a respective geometry such that a wall of the upsetting is folded in a meandering fashion, during movement of the sabot from the starting position into the end position.

12. The interruption switch according to claim 10, wherein the upsetting region is formed hollow-cylindrical or hollow-prismatic, such that upsetting region surrounds a further chamber.

13. The interruption switch according to claim 12, wherein the upsetting region has a perforation, which makes enables a connection between the further chamber and a volume surrounding the further chamber.

14. The interruption switch according to claim 12, wherein the at least one chamber, the further chamber and yet further chamber are filled with the vaporizable medium, wherein the vaporizable medium can be the same or different in the different chambers, wherein the separation region separates the at least one chamber from the yet further chamber which surrounds the separation region in a hollow manner.

Description

(1) The invention is explained in more detail below with reference to the embodiments represented in the drawings. All features which are described in relation to a particular figure can also be transferred to the interruption switches of the other figures, provided this is technically possible:

(2) FIG. 1 shows a longitudinal section through an interruption switch according to the invention in the initial state (sabot in starting position).

(3) FIG. 2 shows a longitudinal section through an interruption switch according to the invention in the end state (sabot in end position).

(4) FIG. 3 shows an arrangement in which an interruption switch according to the invention is connected in parallel with a safety fuse.

(5) FIG. 4 shows an arrangement in which an interruption switch according to the invention is connected in series with two safety fuses.

(6) FIG. 5A shows a separation region of an interruption switch according to the invention with two circumferential grooves.

(7) FIG. 5B shows an interruption switch according to the invention with a separation region according to FIG. 5A.

(8) FIG. 6A shows a separation region of an interruption switch according to the invention with a circumferential thickening (small lump).

(9) FIG. 6B shows an interruption switch according to the invention with a separation region according to FIG. 6A.

(10) FIG. 7 shows an interruption switch according to the invention with a gap between the casing and the sabot, wherein the gap connects the one chamber to the volume surrounding the yet further chamber.

(11) FIG. 8 shows an interruption switch according to the invention with a gap between the casing and the sabot, wherein the sabot is designed such that the one chamber is not connected to the volume surrounding the yet further chamber.

(12) FIG. 9 shows an interruption switch like in FIG. 8, but additionally with circumferential grooves on the sabot.

(13) FIG. 10 shows an interruption switch like in FIG. 9, but without internal insulation on the casing.

(14) The embodiment of an interruption switch 1 according to the invention represented in FIG. 1 comprises a casing 3 in which a contact unit 5, also called connecting element, is arranged. The casing 3 is formed such that it withstands a gas pressure, generated inside the casing, which is generated by vaporization of a vaporizable medium under the influence of an electric arc, without the risk of damage or even bursting. The casing 3 can in particular consist of a suitable metal, preferably steel. In this case, an insulation layer 7 which consists of a suitable insulating material, for example a plastic, can be provided on the inner wall of the casing 3. Polyoxymethylene (POM) can be used for example as plastic for this purpose. In the case of higher voltages, flashovers or an electrical contact between the contact unit 5, which of course consists of a conductive metal, for example of copper, and the casing 3 are hereby avoided, in particular during and after the tripping of the interruption switch 1. However, electrically non-conductive materials such as ceramic, POM, PA6 or ABS are also possible here as casing material, which, however, as a rule have to be suitably reinforced, for example by ribs. In these cases, the wall thickness of the casing 3 will also usually turn out to be thicker than in the case of a metallic casing.

(15) The protective cap 85 shown in FIG. 1 is only present when the casing 3 is closed by a locking nut (not shown). When the casing 3 is depressed after tripping the casing tube would expand in diameter here (the flow of forces is interrupted here), and the screw thread would disengage here, and the assembly would thus burst. The protective cap 85 prevents this expansion and is omitted if the casing 3 is in one piece or is welded on both sides to the washer (not shown) then present here.

(16) In the embodiment example represented, the contact unit 5 extends beyond both ends of the interruption switch 1, is formed predominantly as a tube and comprises a first and a second connection contact 11/13, a separation region 27, a region of a channel 49, an upsetting region 23 and two flanges 15/25a, through which the upsetting region can be depressed by the sabot 25b. In the embodiment example represented, the contact unit 5 has the first connection contact 11 with a larger diameter and the second connection contact 13 with a smaller diameter. Adjoining the first connection contact 11 is the flange 15 extending radially outwards, which is braced on an annular insulator element 17, which consists of an insulating material, for example a plastic, in such a way that the contact unit cannot be moved out of the casing 3 in the axial direction. The plastic used for this can be polyoxymethylene, ABS or nylon, but ceramics are also possible and in special cases are useful. For this purpose, the insulator element 17 has an annular shoulder, on which the flange 15 is braced. In addition, the insulator element 17 insulates the casing 3 from the contact unit 5. The annular insulator element 17, in an axially outer region, has an internal diameter which substantially corresponds to the external diameter of the contact unit 5 in the region of the first connection contact 11. As a result, a sealing action is achieved, which is strengthened by an additional annular sealing element 19, for example an O-ring. The insulator element 17 can also be connected to the contact unit 5 via a press fit, or injection-molded onto it.

(17) The casing 3 is designed on the end face represented on the left in FIG. 1 during the assembly of the interruption switch 1 in such a way that a part of the casing extending radially inwards fixes the insulator element 17. If the casing consists of plastic, the insulator element 17 can also be omitted.

(18) The contact unit 5 has the upsetting region 23 adjoining the flange 15 in the axis of the contact unit 5. In the upsetting region 23, which has a predetermined axial extent, the wall thickness of the contact unit 5 is chosen and adapted to the material in such a way that, when the interruption switch 1 is tripped, as a consequence of a plastic deformation of the contact unit 5 in the upsetting region 23, the upsetting region 23 is shortened in the axial direction by a predetermined distance.

(19) In the axial direction of the contact unit 5, the flange 25a, on which a sabot 25b is seated in the embodiment example represented, adjoins the upsetting region 23. The sabot 25b, which in the embodiment example represented consists of an insulating material, for example a suitable plastic, surrounds the contact unit 5 with its part 25b in such a way that an insulating region of the sabot 25b engages between the outer circumference of the flange 25a and the inner wall of the casing 3. If a pressure acts on the surface of the sabot 25b, a force is generated which compresses the upsetting region 23 of the contact unit 5 via the flange 25a. This force is chosen such that, during the tripping operation of the interruption switch 1, upsetting of the upsetting region 23 occurs, wherein the sabot 25b is moved out of its starting position (status prior to the tripping of the interruption switch 1) into an end position (after the completion of the switching operation).

(20) As can be seen from FIG. 1, the sabot part 25b can be chosen such that its external diameter substantially corresponds to the internal diameter of the casing 3, with the result that an axial guidance of the flange 25a and thus also an axially guided upsetting movement is achieved during the switching operation.

(21) After the pressing operation, the lugs of the insulator element 17 and of the sabot 25b lying near the casing 3 engage over each other completely, with the result that the upsetting region 23, which has been pushed together in a meandering fashion after the tripping and the upsetting operation, is completely surrounded by electrically insulating materials.

(22) Adjoining the sabot 25b or the flange 25a of the contact unit 5 is the separation region 27, which in turn is preferably adjacent to a flange 29 of the contact unit 5 in the axial direction. The second connection contact 13 then adjoins the flange 29. The flange 29 in turn serves to fix the contact unit 5 securely in the casing 3 in the axial direction. This purpose is served by an annular region of the casing 3 (not provided with a reference number) extending radially inwards and a closure 31, which is provided between a corresponding stop face of the flange 29, the inner wall of the end-face annular region of the casing 3 and the axial inner wall of the casing 3, and which annularly surrounds the second connection contact 13 of the contact unit 5. The flange 29 can engage in the closure 31 in the axial direction. As an alternative to this it can also be placed on the closure 31 in the axial direction. The closure 31 can consist of metal, in particular steel.

(23) If the closure 31 does not consist of a metal or a ceramic but rather of a plastic, a metal disc with a diameter which is greater than the right-hand opening of the casing must be introduced after the flange 29 in order, in the event of fire—in the event of fire the plastic parts are no longer there of course—to prevent parts from escaping from the casing 3.

(24) If the casing 3 and the closure 31 are made of steel, it is possible to join these parts to each other by electron-beam or ultrasonic welding. Joining by laser beam is also possible.

(25) In the embodiment example represented, during the assembly of the interruption switch 1, the sabot 25b is pushed onto the contact unit 5 from the side of the connection contact 13 and must therefore be dimensioned such that its internal diameter is greater than or equal to the external diameter of the flange 29.

(26) The closure 31 is designed as an annular component, which has an external diameter which substantially corresponds to the internal diameter of the casing 3, and an internal diameter which substantially corresponds to the external diameter of the flange 29 or the second connection contact 13.

(27) For complete sealing and fixing of the contact unit 5, the interior of the closure element 39 can be potted, in particular with a suitable epoxy resin. The closure element 39 can be provided with a screw thread in order that it can be screwed into the second connection contact 13 of the contact unit 5 but later, if the assembly is implemented in series, for cost reasons it is merely pushed into the second connection contact 13, preferably formed as a tubular part, and then crimped in, clinched or curled.

(28) The closure 31 can consist of a metal, in particular steel. This has the advantage of the connection of potential between the casing 3 and the second connection contact 13. In this way “the casing knows where it belongs with respect to the potential”. The latter is important in high-voltage circuits in order not to obtain any undesired electric arcs with parts having no connection of potential. In addition, the casing 3 shields the inner region of the interruption switch 1 from electromagnetic radiation, e.g. a radar beam.

(29) The separation region 27 is dimensioned such that it tears open completely due to the generated gas pressure, with the result that the pressure can propagate into the further chamber 63 designed as a surrounding annular space. To facilitate the tearing open, the wall of the contact unit can also have one or more openings or holes (not shown) in the separation region 27.

(30) The electrical resistance and thus also the thermal behavior of the separation region 27 can be influenced by the provision of openings in the wall of the separation region 27 (in conjunction, of course, with the wall thickness of the separation region and the dimensioning of the radii at the transitions of the separation region, which substantially determine the heat outflow from the separation region and its rupturing behavior). As a result, the current-time integral at which the interruption switch 1 trips passively can be defined or set. The inertia can also be influenced by such a dimensioning.

(31) In the case of an activation of the interruption switch 1 by means of the passive activation, a gas pressure is thus generated on the side of the sabot 25b facing away from the upsetting region 23, as a result of which the sabot 25b is exposed to a corresponding axial force. This force plastically deforms the contact unit 5 in the upsetting region 23, while the sabot is moved in the direction of the first connection contact 11.

(32) In the embodiment shown in FIG. 1, there is located in the chamber 61 and in the further chamber 63 a vaporizable medium (not shown), which is vaporized when the separation region 27 tears open by the electric arc forming, and the vapor pressure forming in the process exposes the sabot to pressure. The vaporizable medium is preferably at the same time an extinguishing material, with the result that, after the interruption switch has been switched, it can attenuate and cool or extinguish the electric arc between the separated ends of the separation region 27.

(33) On the side of the first connection contact 11 the interruption switch 1 has a closure element 53, which outwardly delimits the one yet further chamber 65 of the contact unit 5.

(34) The channel 49 of the contact unit 5, which extends underneath the sabot 25b, in particular in the flange 25a, preferably centrally in the axial direction, connects the chamber 61 to a yet further chamber 65, which is delimited by the upsetting region 23 and the closure element 53. In the embodiment example represented, the contact unit 5 is thus formed further as a continuous switch tube. Although not shown in FIG. 1, it is preferred for the chamber 61, the channel 49, the yet further chamber 65 and the further chamber 63 to be filled with a vaporizable medium/extinguishing agent. The channel 49 ensures that, when the interruption switch 1 is tripped and during the associated movement of the sabot 25b from the starting position into the end position, the increasing volume in the region of the combustion chamber 61 and the further chamber 63 is also refilled with vaporizable medium/extinguishing agent. Through the movement of the sabot 25b from the starting position into the end position, vaporizable medium/extinguishing agent in the yet further chamber 65 is compressed and injected through the channel 49 in the direction of the region of the chamber 61 and here directly onto the separation point 27. In this way it is ensured that the electric arc between the separated parts of the separation region 27 is extinguished in a controlled manner.

(35) FIG. 2 shows an interruption switch 1 according to the invention according to FIG. 1 in the end state, i.e. in the tripped state, in which the separation region 27 has been separated, the sabot 25b is in the end position and the upsetting region 23 is present upset. Purely by way of example, the interruption switch 1 in FIG. 2 differs from that of FIG. 1 only in that it has a third connection contact 81, as described further above.

(36) FIG. 3 shows an arrangement in which an interruption switch 1 according to the invention is connected in parallel with a safety fuse 87, as described further above. The current I divides as a result of the parallel connection into partial currents I.sub.1 and I.sub.2, wherein I.sub.1 is the current of the safety fuse 87 and I.sub.2 is the current of the interruption switch 1.

(37) FIG. 4 shows by way of example an arrangement in which an interruption switch 1 according to the invention is connected in series with two safety fuses 87, to which the current I is applied. The two safety fuses 87 here are connected before and after the interruption switch 1, i.e. connected to the negative and positive terminals of the interruption switch 1. In such an arrangement the safety fuses have the task mentioned further above.

(38) FIG. 5A shows a hollow-cylindrical separation region 27 with two circumferential grooves 91—as described generally further above. FIG. 5B shows an interruption switch 1 according to the invention with a separation region 27—as shown in FIG. 5A.

(39) FIG. 6A shows a hollow-cylindrical separation region 27 with a circumferential thickening (small lump) 93—as described generally further above. Furthermore, the separation region 27 shown in FIG. 6A has a circumferential groove 91 in each case to the left and right of the circumferential thickening 93. FIG. 6B shows an interruption switch 1 according to the invention with a separation region 27—as shown in FIG. 6A.

(40) The interruption switch 1 in FIGS. 5B and 6B also has a heat sink 1 95 and a heat sink 2 97—as are described generally further above. The heat sinks are only represented by way of example in these figures and can be combined with any further embodiment of the invention. The heat sink 1 95 is preferably mounted in the further chamber on the sabot, and the heat sink 2 97 is mounted on the internal insulation of the casing 3. The heat sink 1 95 can be formed circumferentially, i.e. tubular, or lamellar. The heat sink 2 97 preferably runs circumferentially on the inside of the casing or the internal insulation thereof, i.e. is formed tubular.

(41) Interruption switches 1 according to the invention with a gap 101 between the casing 3 and the sabot 25b are shown in FIGS. 7 to 10. It is preferred here for the gap 101—viewed in cross section—to be present around the whole circumference of the sabot 25b. The gap can connect the one chamber 61 to the volume 103 surrounding the yet further chamber, as shown in FIG. 7. However, the sabot 25b can also be designed such that in the initial state (unswitched state) of the interruption switch 1 the one chamber 61 is not connected to the gap 101, as shown in FIGS. 8 to 10. The sabot 25b can additionally—viewed in the cross section of the interruption switch—have one or more circumferential grooves 105, which act as a labyrinth seal, as shown in FIGS. 9 and 10. Furthermore, these circumferential grooves 105 in the sabot 25b have the effect of a vacuum cleaner for larger particles which are to be removed from the one chamber 61 and the further chamber 63 during the switching operation. In an embodiment of the invention, the sabot 25b thus does not contain any sealing rings in the circumferential grooves 105. If, in the case of interruption switches 1 with a gap 101 in the circumferential grooves 105, one or more sealing ring(s) are provided, then these are designed such that it/they can be flushed out by the pressure forming during the switching operation, thus no longer have a sealing action during the switching operation. As already described further above, in an embodiment of the invention it is preferred for no internal insulation to be provided on the casing, as shown in FIG. 10.

LIST OF REFERENCE NUMBERS

(42) 1 interruption switch 3 casing 5 contact unit (switch tube) 7 insulation layer (internal insulation) 11 first connection contact 13 second connection contact 15 flange of the switch or contact tube 17 insulator element (insulator 1) 19 sealing element (O-ring) 23 upsetting region 25a flange 25b sabot 27 separation region 29 flange 31 closure 39 closure element 49 channel 53 closure element 61 chamber 63 further chamber 65 yet further chamber 81 third connection contact 85 protective cap 87 safety fuse 91 circumferential groove(s) (separation region) 93 circumferential thickening (small lump) 95 heat sink 1 97 heat sink 2 101 gap 103 the volume surrounding the yet further chamber 105 circumferential grooves (sabot) I current I.sub.1 partial current I.sub.2 partial current