Electric interruption switch comprising reactive coating in the reaction chamber

Abstract

An interruption switch is provided for interrupting high currents at high voltages, with a casing, which surrounds a contact unit defining the current path through the interruption switch which has a first and second connection contact and a separation region. The contact unit is formed such that a current can be supplied to it via the first connection contact and can be discharged therefrom via the second connection contact, or vice versa. The separation region is formed such that, when it is separated, the current path between the first connection contact and the second connection contact is interrupted. The separation region is arranged inside a reaction chamber. A coating with a reactive material is present in the reaction chamber. The reactive material is designed such that under the influence of an electric arc it attenuates or extinguishes the electric arc.

Claims

1. An interruption switch for interrupting high currents at high voltages, the interruption switch comprising: a casing, which surrounds a contact unit defining a current path through the interruption switch, the contact unit comprising a first connection contact, a second connection contact and a separation region, wherein the contact unit is formed such that a current is supplied to the contact unit via the first connection contact and discharged therefrom via the second connection contact, or vice versa, wherein the separation region is formed such that, when separated, the current path between the first connection contact and the second connection contact is interrupted, wherein the separation region is arranged inside a reaction chamber; and a coating with a reactive material present in the reaction chamber, wherein the reactive material is configured to, under influence of an electric arc, attenuate or extinguish the electric arc, wherein the reaction chamber is filled with an extinguishing agent which is a liquid medium; and, wherein the coating is substantially free of carbon-containing materials.

2. The interruption switch according to claim 1, wherein the reactive material is further configured to, under the influence of the electric arc, react to absorb energy from the electric arc.

3. The interruption switch according to claim 1, wherein the reactive material is further configured to, under the influence of the electric arc, be converted to non-conductive substances.

4. The interruption switch according to claim 1, wherein the reactive material is further configured to, under the influence of the electric arc, be vaporized.

5. The interruption switch according to claim 1, wherein the reactive material is further configured to, under the influence of the electric arc, be decomposed into reaction products configured to enter an exothermic reaction.

6. The interruption switch according to claim 1, wherein the reactive material comprises a ceramic material or glass.

7. The interruption switch according to claim 1, wherein the reactive material comprises a material based on SiO.sub.2.

8. The interruption switch according to claim 1, wherein the contact unit comprises a sabot, or is connected to the sabot, the sabot configured to move from a starting position into an end position by exposure to pressure, wherein, in the end position of the sabot, the separation region is separated and an insulation spacing between the first connection contact and the second connection contact is achieved.

9. The interruption switch according to claim 8, wherein the contact unit comprises a surface directed towards the separation region which acts as the sabot, such that surface is moved from the starting position into the end position by exposure to pressure, wherein, in the end position of the sabot, the separation region is separated and the insulation spacing between the first connection contact and the second connection contact is achieved.

10. The interruption switch according to claim 1, wherein the extinguishing agent comprises a vaporizable agent.

11. A method comprising: coating surfaces of a reaction chamber of an interruption switch with a reactive material, wherein the reactive material is configured to, under influence of an electric arc, react to attenuate or extinguish the electric arc, wherein the reaction chamber is filled with an extinguishing agent which is a liquid medium; and, wherein the reactive material is substantially free of carbon-containing materials.

12. The method according to claim 11, wherein the reactive material is applied to the surfaces as a liquid material and then dried.

13. The method according to claim 12, wherein the reactive material is a liquid ceramic or liquid glass.

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, if technically feasible:

(2) FIG. 1 shows a schematic view of an interruption switch according to the invention before the separation of the separation region.

(3) FIG. 2 shows a schematic view of the interruption switch according to the invention according to FIG. 1 after the separation of the separation region.

(4) FIG. 3 shows a schematic view of an interruption switch according to the invention before the separation of the separation region, wherein the separation region has two possible predetermined breaking points.

(5) FIG. 4 shows a schematic view of the interruption switch according to the invention according to FIG. 3 after the separation of the separation region, with two separation points.

(6) FIG. 5 shows an oscillogram of different measured currents and voltages in an interruption switch without coating according to the invention, in which the separation of the separation region has been effected by means of a pyrotechnic material (timescale: 200 μs/scale division).

(7) FIG. 6 shows an oscillogram as in FIG. 5 with a timescale of 500 μs/scale division.

(8) FIG. 7 shows an oscillogram of different measured currents and voltages in an interruption switch according to the invention, in which the surfaces of the reaction chamber were coated with a reactive material before the separation (timescale: 200 μs/scale division).

(9) FIG. 8 shows an oscillogram as in FIG. 7 with a timescale of 5 ms/scale division.

(10) FIG. 9 shows a schematic view of an interruption switch used in the measurements of the oscillograms shown in FIGS. 7 and 8 before the separation of the separation region.

(11) FIG. 10 shows a schematic view of an interruption switch, with an internal insulation layer on the inner wall of the reaction chamber instead of the sabot used in FIG. 9 made of insulating material, which has the same good separation properties with subsequent good insulation resistance between the separated contacts.

(12) FIG. 1 and FIG. 2 show schematic views of an interruption switch 1 according to the invention before and after the separation of the separation region 6. The interruption switch 1 has a casing 2, through which the contact unit 3 passes. The contact unit 3 has a first connection contact 4 on one side and a second connection contact 5 on the other side, which are electrically connected to each other via the separation region 6 in the interruption switch 1 in FIG. 1. The separation region 6 runs through a reaction chamber 7, which is surrounded by the casing 2. As shown in FIG. 1, the separation region 6 can have one predetermined breaking point 13, but can have two or more predetermined breaking points. The reaction chamber 7 is preferably filled with an extinguishing agent 9. Furthermore, a drive 11 which is connected to a ram 12 is provided in the reaction chamber 7. The drive 11 can be designed for example as a pyrotechnic drive. If the drive 11 is actuated, the ram 12 applies pressure to the separation region 6 of the contact unit 3. In the process a separation of the separation region 6 occurs at the predetermined breaking point 13, whereby the first connection contact 4 and the second connection contact 5 are no longer connected. FIG. 1 shows the interruption switch 1 in the conductive position, whereas FIG. 2 shows the same interruption switch 1 after being switched into the non-conductive position, in which the separation region 6 is separated into the separated parts 6a and 6b. Furthermore, a coating 8 with the reactive material, which preferably extends completely over the inner wall of the reaction chamber 7, is provided in the interruption switch 1. Alternatively or additionally, a corresponding coating can be present on all surfaces of the further components inside the reaction chamber, such as for example the ram 12 or the drive 12.

(13) FIG. 3 and FIG. 4 likewise show schematic views of an interruption switch 1 according to the invention before and after the separation of the separation region 6. The interruption switch 1 in FIG. 3 and FIG. 4 is in principle constructed in a similar way to the interruption switch 1 in FIG. 1 and FIG. 2, with the difference that the separation region 6 has two predetermined breaking points 13, which are separated via the ram 12 when the drive 11 is actuated. FIG. 4 shows the interruption switch 1 in the so-called separation position, in which the separation region 6 is separated into three parts 6a, 6b, 6c. All named preferred features of the interruption switch of FIGS. 1 and 2 also apply to the interruption switch of FIGS. 3 and 4.

(14) The oscillograms shown in FIGS. 5 to 8 contain the measurements

(15) of the ignition current for the pyrotechnic material formed as an EED,

(16) of the voltage of the discharging capacitor charged before the interruption switch is tripped,

(17) of the current to be separated over the two connection contacts and

(18) of the voltage over the two connection contacts separated after the pyrotechnic material has been triggered.

(19) The oscillograms of FIGS. 7 and 8 show measurements with an interruption switch 1 with a coating 8 of a reactive material in the reaction chamber 7, as shown in FIG. 9 and described further below. The oscillograms of FIGS. 5 and 6 show measurements with an interruption switch, as shown in FIG. 9, with the only difference that here the inner wall of the reaction chamber 7 is not provided with a coating 8 of a reactive material. The x-axis defines the time in all oscillograms shown. The y-axis defines either the direct voltage or the direct current. The respective zero points are marked in the oscillograms. In FIGS. 5 and 7 one scale division (from one point to the next) defines a time span of 200 μs. FIG. 6 shows the same measurement as in FIG. 5, with the difference that one scale division defines a time span of 500 μs. FIG. 8 shows the same measurement as in FIG. 7, with the difference that one scale division defines a time span of 5 ms. With respect to the ignition current, one scale division (from one point to the next) in all of FIGS. 5 to 8 defines a current of 10 A. With respect to the capacitor voltage, one scale division in all of FIGS. 5 to 8 defines a voltage of 500 V. With respect to the short-circuit current to be separated, one scale division in all of FIGS. 5 to 8 defines a current of 2500 A. With respect to the voltage over the connection contacts of the interruption switch (denoted Powerfuse in the figures), one scale division in FIGS. 5, 6 and 8 defines a voltage of 500 V, and in FIG. 7 a voltage of 200 V.

(20) As can be seen from the comparison of the oscillograms of the interruption switch 1 according to the invention with coating 8 (FIGS. 7 and 8) with the interruption switch not according to the invention without coating (FIGS. 5 and 6), in both interruption switches an excellent separation effect occurs, but only when an interruption switch according to the invention is used is a sufficiently good insulation obtained between the separated contacts after successful separation.

(21) Thus, the measured voltage over the separated connection contacts 4 and 5 in FIG. 7 already begins to drop off after 500 μsec after successful separation, and thereafter down to 0 V, and the current still flowing here discharges the residual energy still present in the discharging capacitor, whereas that is not the case in FIG. 8, where this voltage is preserved.

(22) The slight drop-off to be seen in FIG. 8 of the voltage over the connection contacts 4 and 5 of the interruption switch 1 after successful separation is effected via the discharge resistors of the discharge bank and not by the current flow (not present here) through the interruption switch 1.

(23) The embodiment represented in FIG. 9 of an interruption switch 1 according to the invention comprises a casing 2, in which a contact unit 3 is arranged. The casing 2 is formed such that it withstands a pressure, generated inside the casing 2, which is generated for example in the case of a pyrotechnic tripping of the interruption switch 1, without there being the danger of damage or even bursting. The casing 2 can consist in particular of a suitable material, preferably steel. In the embodiment example represented, the contact unit 3 is formed as a switch tube that is depressed by the sabot 10 in the upsetting region, with the result that it is formed as a tube in the separation 6 and upsetting 19 regions. In the embodiment example represented, the contact unit 3 has a first connection contact 4 with a larger diameter and a second connection contact 5 with a smaller diameter. Adjoining the first connection contact 4 is a flange 15 extending radially outwards, which is braced on an annular insulator element 22, which consists of an insulating material, for example a plastic, in such a way that the contact unit 3 cannot be moved out of the casing 2 in the axial direction. For this purpose, the insulator element 22 has an annular shoulder, on which the flange 15 of the contact unit 3 is braced. In addition, the insulator element 22 insulates the casing 2 from the contact unit 3. The contact unit 3 has an upsetting region 19 adjoining the flange 15 in the axis of the contact unit 3. In the upsetting region 19, which has a predetermined axial extent, the wall thickness of the contact unit is chosen and matched to the material such that, when the interruption switch 1 is tripped as a result of a plastic deformation of the contact unit 3 in the upsetting region 19, the upsetting region is shortened in the axial direction by a predetermined distance.

(24) Adjoining the upsetting region 19 in the axial direction of the contact unit is a flange 14, on which a sabot 10 sits in the embodiment example represented. The sabot 10, which consists of an insulating material, for example a suitable plastic, in the embodiment example represented, surrounds the contact unit 3 in such a way that an insulating region of the sabot 10 engages between the outer circumference of the flange 14 and the inner wall of the casing 2. If a pressure acts on the surface of the sabot 10, a force is generated which compresses the upsetting region 19 of the contact unit 3 via the flange 14. This force is chosen such that, during the tripping operation of the interruption switch 1, an upsetting of the upsetting region 19 occurs, wherein the sabot 10 is moved from its starting position (status before the interruption switch 1 is tripped) into an end position (after the switching operation has been completed).

(25) As can be seen from FIG. 9, the sabot 10 can be chosen such that its external diameter substantially corresponds to the internal diameter of the casing 2, with the result that an axial guidance of the flange 14 and thus also an axially guided upsetting movement during the switching operation is achieved.

(26) After the pressing operation the lugs of the insulator 22 and of the sabot 10 located close to the casing 2 overlap completely, with the result that the upsetting region 19 pushed together in a meandering fashion after the tripping and the upsetting operation is completely surrounded by electrically insulating materials.

(27) Adjoining the sabot 10 or the flange 14 of the contact unit 3 is a separation region 6. The second connection contact 5 then adjoins this side of the contact unit 3. A closure 24 closes the casing 2.

(28) In the embodiment example represented the sabot 10 is pushed onto the contact unit 3 from the side of the connection contact 5 during the assembly of the interruption switch 1. The closure 24 is designed as an annular component which has an external diameter which substantially corresponds to the internal diameter of the casing 2.

(29) In the axial end of the contact unit 3 in the region of the second connection contact 5 a drive 11, preferably a pyrotechnic drive, is provided, here often also called a mini detonator or a priming screw. The electrical connection lines 20 of the drive 11 can be guided outwards through an opening in the annular closure 24.

(30) The separation region 6 is dimensioned such that it tears open at least partially through the gas pressure generated or the shock wave generated by the drive 11, with the result that the pressure or the shock wave can also propagate out of the combustion chamber 17 into the reaction chamber 7 designed as a surrounding annular space. To facilitate the tearing open, the wall of the contact unit 3 in the separation region 6 can also have one or more openings or holes and/or grooves.

(31) The drive 11 for igniting the pyrotechnic material (ignition device) can consist of a simple, rapidly heatable glow wire. The activation of the drive 11 can be effected by a corresponding electrical actuation. Of course, however, the drive 11 can also be formed in any other desired manner which brings about an activation of the pyrotechnic material, also in the form of a conventional igniter (EED), an ignition tablet, a squib or a mini detonator.

(32) When the interruption switch 1 is activated by means of the drive 11, a pressure or a shock wave is thus generated on the side of the sabot 10 facing away from the upsetting region 19, whereby the sabot 10 is exposed to a corresponding axial force. This force is chosen through a suitable dimensioning of the pyrotechnic material such that in the upsetting region 19 the contact unit 3 is plastically deformed, torn open or caved in, and the sabot 10 is then moved in the direction of the first connection contact 4. The pyrotechnic material is dimensioned such that, after the separation region 6 has been broken open or caved in, the movement of the sabot 10 moves the two separation halves sufficiently far away from each other, in cooperation with the vaporization of the extinguishing agent 9 then even into an end position.

(33) Directly after the pyrotechnic material has been activated, the separation region 6 is thus at least partially torn open or caved in. If the tearing open or caving in has not already been effected before the start of the axial movement of the sabot 10 over the entire circumference of the separation region 6, a residual remainder of the separation region 6, which causes another electrical contact, is completely torn open by the axial movement of the sabot 10, intensified by the very rapid heating then occurring here of the residual cross section of the conductor, which is then only small here, due to the electric current flowing here.

(34) In particular, the gas pressure generated by the combustion or the shock wave generated can be controlled well by the introduction of easily gasifiable liquids or solids (extinguishing agent 9) into the space in which the pyrotechnic material is contained or into which the hot gases generated penetrate. Thus, in particular water, in solution with the extinguishing agent 9 or in the form of microcapsules, gels etc., increases the gas pressure considerably; an admixture of chemicals which also react when heated also makes sense, e.g. the addition of red phosphorus, but in particular also of particular combustible and ignition substances, such as zirconium potassium perchlorate (ZPP), but also of polysiloxanes such as hexasilane or pentasilane. An increase in the gas pressure brought about in such a way can turn out to be even more extreme if, for example, the water introduced into the combustion chamber 17 is superheated, in particular because the strongly heated water experiences an explosive decompression when the separation region 6 is broken open.

(35) In the embodiment shown in FIG. 9, an extinguishing agent 9 which promotes the propagation of the shock wave when the pyrotechnic material is detonated or deflagrated is located in the combustion chamber 17 and in the reaction chamber 7, with the result that in this way less activatable material needs to be used and the walls of the separation region 6 can be kept sufficiently thick, with the result that the assembly can also be used even in the case of high operating currents. The extinguishing agent serves to attenuate or extinguish an electric arc between the separated ends of the separation region 6.

(36) Furthermore, a coating with a reactive material is provided in the reaction chamber 7, preferably a layer of SiO.sub.2 which covers the entire inner wall of the reaction chamber 7 and preferably has a layer thickness of 30 μm.

(37) Furthermore, in the interruption switch 1 according to the invention of FIG. 9 a channel is provided which extends underneath the sabot 10, in particular in the flange 14, preferably centrally in the axial direction, and connects the combustion chamber 17 to an upsetting chamber 18 underneath the upsetting region 19. The contact unit 3 is thus further formed as a continuous switch tube in the embodiment example represented. In this embodiment, the combustion chamber 17, the channel, the reaction chamber 7 and the upsetting chamber 18 can all be filled with the extinguishing agent 9. The channel ensures that, in the case of the tripping of the interruption switch 1 and the movement of the sabot 10 associated therewith from the starting position into the end position, the increasing volume in the region of the combustion chamber 17 and the reaction chamber 7 is also refilled with extinguishing agent 9. Through the movement of the sabot 10 from the starting position into the end position, extinguishing agent 9 in the upsetting chamber 18 is compressed and injected through the channel in the direction of the region of the combustion chamber 17 and here directly onto the separation region 6. In this way, an electric arc between the separated parts of the separation region 6 can additionally be attenuated or extinguished.

(38) The central channel can be narrowed in the manner of a nozzle before the combustion chamber 17 or before the separation region 6, in order firstly to allow extinguishing agent 9 to pass sufficiently well from the upsetting region 19 into the combustion chamber 17, secondly to weaken the shock wave generated by the mini detonator towards the upsetting region 19 such that the upsetting region is not too greatly damaged beforehand after the ignition of the mini detonator.

(39) Furthermore, sealing elements 23 for sealing the different chambers 7, 17 and 18 against the escape of extinguishing agent 9 and for sealing the different components from each other are provided in the interruption switch 1.

(40) The interruption switch 1 according to FIG. 9 is in principle constructed exactly like the interruption switch of DE 10 2016 124 176 A1 shown in FIG. 5.

(41) The interruption switch 1 of FIG. 10 is identical to the interruption switch of FIG. 9 except for the following changes:

(42) Between the separation region 6 and the upsetting region 19 of the contact unit 3 the flange 14 shown in FIG. 9 is formed such that it reaches as far as an insulation layer 21 applied to the inside of the casing 2. The contact unit 3 itself thus has the sabot 10 or the function of a sabot 10. This has the advantage of saving material and simpler design of the interruption switch 1. The insulation layer 21 here creates an insulation between the contact unit 3 and the casing 2.

(43) The contact unit 3 now also fulfills at the same time also the function of the closure, with the result that here a further component of the assembly is dispensed with, and in addition, during the production of the contact unit 3, either less machining or less forming is needed here, which further reduces the production costs.

(44) The interruption switch used for the measurements of the oscillograms of FIGS. 5 to 8 has the dimensions shown in FIG. 9, wherein the length of the casing is 52 mm and the diameter of the casing is 30 mm. The casing is made of steel. The drive is a mini detonator with 30 mg silver azide and 40 mg RDX. The extinguishing agent is a mixture of silicone oil and highly dispersible silica (HDS) (40 cm3 oil to 2 g HDS). Polysiloxanes are the reactive material of the coating in the reaction chamber and the layer thickness is approximately 30 μm. The contact unit is shaped cylindrically and consists of copper. The separation region has an internal diameter of 6 mm and an external diameter of 7.2 mm. The complete length of the contact unit including the connection contacts is 85 mm.

LIST OF REFERENCE NUMBERS

(45) 1 interruption switch

(46) 2 casing

(47) 3 contact unit

(48) 4 first connection contact

(49) 5 second connection contact

(50) 6 separation region

(51) 6a, 6b, 6c separated parts of the separation region

(52) 7 reaction chamber

(53) 8 coating

(54) 9 extinguishing agent

(55) 10 sabot

(56) 11 drive

(57) 12 ram

(58) 13 predetermined breaking point

(59) 14 flange

(60) 15 flange

(61) 16 drive

(62) 17 combustion chamber

(63) 18 upsetting chamber

(64) 19 upsetting region

(65) 20 electrical connection lines

(66) 21 insulation layer

(67) 22 insulator element

(68) 23 sealing element (O-ring)

(69) 24 closure

(70) 25 closure element for upsetting chamber