EP0836209A2 - Circuit breaker - Google Patents

Abstract

The circuit-breaker has a rotationally symmetrical arc- extinction chamber, with a pair of diametrically opposing spaced contact devices (5,6) aligned with its central axis (2), which can be bridged by a bridging contact extending along this axis. The annular gap (36) between the contact devices is enclosed by an annular heating volume (13), directly communicating with the annular gap.

Description

TECHNICAL AREA

The invention is based on a circuit breaker according to the preamble of claim 1.

STATE OF THE ART

From patent EP 0 313 813 B1 is a Circuit breaker known, its arcing chamber Combustion contacts, both in opposite directions Direction, and not by one shown drive in connection with two each other racks arranged diametrically opposite each other in Connection with corresponding gears.

From the published patent application DE 42 11 158 A1 a circuit breaker is known which has an arcing chamber with two erosion contacts, one of which is designed to be movable. The quenching chamber is filled with an insulating gas, preferably SF ₆ gas under pressure. A nominal current path is arranged concentrically around the erosion contacts and carries the current when the arcing chamber is switched on. A heating volume is provided in the interior of the movable erosion contact, which is supplied with hot gas from the arc zone of the quenching chamber under increased pressure. The heating volume is connected to the arc zone by means of a narrow heating duct. This heating channel is comparatively long, and it also has a right-angled bend. This kinking hinders the flow of the hot gas generated by the arc into the heating volume because it reflects pressure waves. These pressure waves temporarily block the flow towards the heating volume. When the arc starts blowing, this kinking also hinders the flow into the arc zone, and the cooling effect of the blowing is therefore somewhat reduced. The heating volume is additionally supplied with cold gas in a known manner when switching off from a compression volume.

From patent EP 0 163 943 B1 is a concentric built circuit breaker known, the one Power pathway that extends from an axially Heating volume is surrounded concentrically. The power track has a movable and a fixed Burn contact on. Between the erosion contacts and the Heating volume is an intermediate volume. After Contact separation is caused by the resulting arc first the insulating gas is heated in the intermediate volume. This Intermediate volume increases the arcing zone Circuit breaker. The arc zone of this Circuit breaker is by means of a radially outward extending annular gap with the symmetrical to the annular gap arranged heating volume, in which the in the Hot gas generated in the arc zone flows. In this Heating volume, the hot gas is temporarily stored. The Heating volume is rigid with the fixed erosion contact connected. In this embodiment of the circuit breaker is the mixing of the cold in the heating volume Insulating gas with the hot gas flowing in when it is switched off not be particularly effective. In addition, the Pressure increase in the heating volume somewhat delayed, because for the heating of the insulating gas in the intermediate volume in advance must be used.

From the published patent application DE 42 00 896 A1, a circuit breaker is known which has an arcing chamber with an external nominal current path and two fixed, spaced-apart erosion contacts. The quenching chamber is filled with an insulating gas, preferably SF ₆ gas under pressure. When the arcing chamber is switched on, the two erosion contacts are connected to one another in an electrically conductive manner by means of a movable bridging contact. The bridging contact concentrically surrounds the cylindrical erosion contacts. The bridging contact and the two erosion contacts form a power current path which is only subjected to current when it is switched off. When switched off, the bypass contact slides down from a first of the erosion contacts and draws an arc, which initially burns between the first erosion contact and the end of the bypass contact facing it. As soon as this end reaches the second erosion contact, the arc base commutates from the end of the bridging contact to the second erosion contact, the arc now burns between the two erosion contacts. The gas heated in the arcing zone flows through a long heating channel into a heating volume arranged inside the bridging contact, where it is temporarily stored. The heating volume is additionally supplied with cold gas in a known manner when switching off from a compression volume. The pressurized insulating gas required for blowing the arc is then introduced through the heating duct into the arc zone. The comparatively long heating duct causes considerable flow resistance, and the energy lost due to flow losses is then missing when the arc is blown.

PRESENTATION OF THE INVENTION

The invention as set out in the independent claims is marked, solves the task one To create circuit breakers at which the Flow conditions in the area between the arc zone and Heating volumes are significantly improved.

Since in the circuit breaker according to the invention Heating volume immediately adjacent to the arc zone and Arranged symmetrically to this, both occur when Outflow of the hot gases into the heating volume as well Blowing the arc out of the heating volume none Flow losses on, making one quicker Pressure build-up in the heating volume and on the other hand a special one effective cooling of the arc is guaranteed. The Heating volume can also because of this special arrangement better filled with pressurized hot gas or store a large amount of hot gas, resulting in a more intense blowing of the arc is possible.

The switching pin serving as a bridging contact is in Inside the erosion contact arrangements, along the central one Axis extends, arranged and can be advantageous with one small diameter and thus with a particularly small Mass run. This low mass Bridging contact can be made with a comparatively small one and advantageously cheap drive accelerated effectively and reliable again at the end of the switch-off movement be slowed down.

The erosion contact arrangements are inside the Counter contact arranged. The external nominal current path, especially their contact fingers and the contact surfaces which they glide against are very good against the direct ones The effects of the arc are protected, reducing their Stability and thus their lifespan advantageous is increased. The maintenance intervals for the This will result in rated current contacts of the circuit breaker advantageously increased, so that the availability of the Circuit breaker is increased significantly.

If that is saved for blowing the arc Hot gas fresh, from a piston-cylinder arrangement compressed insulating gas is added, so increases the effect of the blowing advantageous.

With the help of the baffle arranged in the heating volume becomes a favorable vortex formation and consequently one particularly intimate mixing of the hot gas with the compressed insulating gas is reached, causing another Increase in the breaking capacity of the circuit breaker is achieved. The related to the geometry of the Burning contact arrangements symmetrical arrangement of the Heating volume means that the entire heating volume evenly filled and mixed, so that total volume for storing the for blowing the Arc gas mixture to be provided can.

The targeted partial closing of the annular gap between the erosion contact arrangements by means of openings having rings made of insulating material brings the advantage with that being bothersome, from the arc any influences are kept away from the heating volume, and that on the other hand the hot gas flowing through is swirled effectively, so that a particularly intensive mixing of the hot gas with the compressed insulating gas can take place.

The further refinements of the invention are objects of the dependent claims.

The invention, its further development and the achievable with it Advantages are shown below using the drawing, which represents only one possible way of execution, closer explained.

BRIEF DESCRIPTION OF THE DRAWING

Fig.1 einen stark vereinfachten Schnitt durch die Kontaktzone einer ersten Ausführungsform der Löschkammer eines erfindungsgemässen Leistungsschalters im eingeschalteten Zustand,

Fig.2 einen stark vereinfachten Schnitt durch die Kontaktzone einer zweiten Ausführungsform der Löschkammer eines erfindungsgemässen Leistungsschalters während des Ausschaltens,

Fig.3 einen stark vereinfachten Schnitt durch die Kontaktzone einer dritten Ausführungsform der Löschkammer eines erfindungsgemässen Leistungsschalters im ausgeschalteten Zustand,

Fig.4 einen stark vereinfachten Schnitt durch die Kontaktzone einer vierten Ausführungsform der Löschkammer eines erfindungsgemässen Leistungsschalters, wobei in der oberen Hälfte der eingeschaltete Zustand und in der unteren Hälfte der ausgeschaltete Zustand dargestellt ist,

Fig.5a bis 5d mehrere Beispiele, wie die Verbindung zwischen einem Heizvolumen und der Lichtbogenzone eines erfindungsgemässen Leistungsschalters konstruktiv gestaltet werden kann,

Fig.6a bis 6c weitere Beispiele für die konstruktive Gestaltung der Verbindung zwischen dem Heizvolumen und der Lichtbogenzone, und

Fig.7 eine weitere Gestaltungsmöglichkeit für die Verbindung zwischen dem Heizvolumen und der Lichtbogenzone.

Show it:

1 shows a greatly simplified section through the contact zone of a first embodiment of the arcing chamber of a circuit breaker according to the invention in the switched-on state,

2 shows a greatly simplified section through the contact zone of a second embodiment of the arcing chamber of a circuit breaker according to the invention during the opening,

3 shows a greatly simplified section through the contact zone of a third embodiment of the arcing chamber of a circuit breaker according to the invention in the switched-off state,

4 shows a greatly simplified section through the contact zone of a fourth embodiment of the arcing chamber of a circuit breaker according to the invention, the switched-on state being shown in the upper half and the switched-off state in the lower half,

5a to 5d show several examples of how the connection between a heating volume and the arcing zone of a circuit breaker according to the invention can be designed,

6a to 6c further examples of the structural design of the connection between the heating volume and the arcing zone, and

7 shows another design option for the connection between the heating volume and the arcing zone.

In all figures, elements with the same effect are the same Provide reference numerals. For the sake of clarity the visible edges are partly omitted in the figures. None for the immediate understanding of the invention required elements are not shown.

WAYS OF CARRYING OUT THE INVENTION

1 shows a greatly simplified section through the contact zone 1 of a first embodiment of the arcing chamber of a circuit breaker according to the invention in the switched-on state. This quenching chamber is arranged symmetrically about a central axis 2. The housing enclosing this contact zone 1 is not shown. This housing is filled with an insulating medium, for example SF ₆ gas under pressure. A centrally arranged, cylindrical, metallic switching pin 3 extends along this central axis 2 and can be moved along the central axis 2 by means of a drive (not shown). The switching pin 3 has a dielectrically favorably shaped tip 4, which can be provided with an electrically conductive, erosion-resistant material if required. In the switched-on state, the switching pin 3 bridges an electrically gap-shaped distance a, which is provided between two cylindrical, opposing erosion contact arrangements 5 and 6. As a rule, the switching pin 3 is electrically conductively and slidably connected to a first, not shown, power connection of the arcing chamber arranged on the left side.

These erosion contact arrangements 5 and 6 are mechanical rigidly connected and are common along the central axis 2 movable. During the switch-off process is between the erosion contact arrangements 5 and 6 and Part in the inner bore of the arc zone of the Circuit breaker provided. The erosion contact arrangement 5 has a cap 7 made of a temperature-resistant Insulating material on which a resilient, on the Surface of the switch pin 3 lying, electrically conductive contact basket 8 surrounds. The erosion contact arrangement 6 can be similar to that Burn-up contact arrangement 5 with a resilient, electrically conductive contact basket 10 inside, which on the surface of the switching pin 3 rests. The The erosion contact arrangement 6 is also provided with a cap 9 made of a temperature-resistant insulating material, which surrounds the contact basket 10. There are others too Designs of erosion contact arrangements conceivable, such as for example beyond the contact baskets 8 and 10 advanced burnout contacts, which burn off prevent the contact baskets 8 and 10. Especially at high Shutdown currents such burnout contacts are used to the stability of the contact baskets 8 and 10 improve. In principle, it is also possible to use one of the caps 7 or 9 to be electrically conductive, and the relevant Use the cap as a burn-up contact.

The erosion contact arrangement 6 has a metal manufactured holding part 11, which is electrically conductive with the contact basket 10 is connected. The holding part 11 carries also the cap 9 and a cylindrical one Insulating tube 12, which is centered on the central axis 2 is arranged and which of the two Burn-up contact arrangements 5 and 6 mechanically rigidly connects and a heating volume 13 encompassing this in an annular manner on the limited the side facing away from the central axis 2. The Holding part 11 has a collar 14 which in one fixed metallic contact cylinder 15 slides. The outside of the collar 14 facing the contact cylinder 15 is with contact elements, not shown, for example with spiral contacts and the associated guide rings Plastic, which provide the power transfer from the federal government 14th ensure the holding part 11 on the contact cylinder 15.

The fixed contact cylinder 15 is on the left side with the first power connection, not shown, the Extinguishing chamber rigidly connected. The contact cylinder 15 is in the area located radially outside the insulating tube 12 provided with resilient contact fingers 16, one side is rigidly connected to the contact cylinder 15, for example by means of soldering or by caulking or pressing. These contact fingers 16 are part of the Nominal current path. The resilient ends of the contact fingers 16 are on the outside with the extinguishing chamber switched on a cylindrical one, along the central axis 2 movable, electrically conductive Nominal current contact tube 17, which makes the flawless Current transition between the nominal current contact tube 17 and the Contact cylinder 15 is ensured. The Nominal current contact tube 17 is by means of not shown Sliding contacts with a likewise not shown second power connection of the extinguishing chamber on the right side rigidly connected.

The nominal current contact tube 17 is on the contact cylinder 15 facing side designed dielectric favorable. In the nominal current contact tube 17 is on this side electrically conductive cylinder bottom 18 embedded. On this The cylinder base 18 is the contact basket 8 electrically conductive molded in the direction of the Burn-up contact arrangement 6 extends too. The cap 7 is in attached to the cylinder bottom 18, the insulating tube 12 is on this side of the heating volume 13 also by the Cylinder base 18 held. The heating volume 13 is in the Usually symmetrical to the annular gap-shaped distance a arranged. Openings 19 are in the cylinder base 18 incorporated by means of a schematically represented Check valve 20 are closable so that during the switching off of the extinguishing chamber in the heating volume 13 stored pressurized hot gas not through these breakthroughs 19 can escape.

In the nominal current contact tube 17 is an annular formed compression volume 21 let in. The Compression volume 21 is on the one hand by the Cylinder base 18 and on the other hand by a fixed Compression piston 22 limited. The compression piston 22 leads the nominal current contact tube 17, which slides on it, and limits this cylindrical sliding surface at the same time the compression volume 21 in the radial direction outward. On the cylinder bottom 18 is on the Compression piston 22 to extend pipe 23 pressure-tight molded on, which the compression volume 21 radially after limited inside.

The tube 23 slides inside the compression piston 22 load-bearing piston skirt 24. One in the piston skirt 24 inserted sliding seal 25 seals the compression volume 21 at this point. One in the outer cylinder surface of the compression piston 22 inserted sliding seal 26 seals the compression volume 21 at this point. The Sliding seals 25 and 26 are designed so that the Mating contact 17 the compression piston 22 or the Piston shaft 24 does not touch metallic, so that over the Compression piston 22 can not flow stray currents. In breakthroughs 27 are incorporated into compression piston 22, which is represented by a schematically Check valve 28 are closable so that during the shutdown of the quenching chamber in the Compression volume 21 did not produce pressurized gas can escape through these openings 27. Is this Check valve 28 is open, so is the compression volume 21 with the quench chamber volume 29, which is shown Contact zone 1 surrounds and which of them does not extinguishing chamber housing shown is connected. The inner volume 30 of the tube 23 is as well as one of the holding part 11 enclosed volume 31 with the Quench chamber volume 29 connected.

FIG. 2 shows a somewhat modified version compared to FIG. 1 Embodiment of the contact zone 1, namely in the area the check valve 20 inside the heating volume 13 attached annular baffle 32, which surrounds the erosion contact arrangement 5 concentrically and which is responsible for a swirling of the Check valve 20 inflowing cold gas with the im Heating volume 13 stored hot gas. This Guide plate 32 can be provided with corresponding guide vanes be or other that influence the gas flow Have components. The others to contact zone 1 belonging components are designed in the same way as in Fig.1 components shown.

The position shown in Fig.2 shows the arcing chamber while switching off. First was the outside Rated current path interrupted and the breaking current then commutated to the internal power path. When switched off, it moves to the power circuit belonging switching pin 3 to the left, like an arrow 33 indicates, and at the same time that assigned to the nominal current path Nominal current contact tube 17 to the right, like an arrow 34 implies. In the shown position of contact zone 1 the switching pin 3 bridges the erosion contact arrangements 5 and 6, or the contact baskets 8 and 10, no longer, i.e. the power path is already broken and on through the switching pin 3 initiated arc 35 burns between the contact baskets 8 and 10. The through the Arc 35 generated hot gases flow through in part the annular gap 36 between the two insulating caps 7 and 9 in the heating volume 13.

3 shows the extinguishing chamber in the off position already extinguished arc. This arcing chamber points compared to that shown in Fig.2 a slightly modified Embodiment of the contact zone 1, in the area of Check valve 20 is in the interior of the heating volume 13 frustoconical guide plate 32 attached, which concentrically surrounds the erosion contact arrangement 5, and what a swirl of the by Check valve 20 inflowing cold gas with the im Heating volume 13 stored gas ensures. The check valve 20 is shown here in the open state. This baffle 32 can be provided with corresponding guide vanes or other components influencing the gas flow exhibit. The others belonging to contact zone 1 Components are designed the same as those in Fig.1 components shown.

1 to 3 show a circuit breaker, in which both the nominal current contact tube 17 and the switching pin 3 is designed to be movable. As a rule, they will Rated current contact tube 17 and the switching pin 3 with the same speed in opposite to each other Directions moved. The patent EP 0 313 813 B1 gives for example a circuit breaker with a drive, with which this described course of movement is achieved. However, it is also possible with comparatively little Effort to create a circuit breaker where the Rated current contact tube 17 and the switching pin 3 with different opposing, the respective Speeds adapted to operating requirements work.

It is also possible to use the circuit breaker with only to equip a moving contact if, for example, only a comparatively low breaking capacity is required, This somewhat cheaper circuit breaker version is sufficient fully. 4 is such a simplified and particularly inexpensive circuit breaker shown. Of the basic structure is the same as that shown in Fig.1 Circuit breaker, only the switching pin 3 is shorter trained, its tip 4 no longer protrudes above the Front edge 37 of the contact cylinder 15 also. Of the Switch pin 3 is electrically conductive and rigid with the Contact cylinder 15 connected. In the upper half of Fig.4 is contact zone 1 in the switched-on state shown. In the lower half of Fig.4 is the Contact zone 1 shown in the switched-off state. The Nominal current contact tube 17 is in its right Switched off position. In addition, in the in the lower half of Fig.4 shown Circuit breaker design a baffle 32 as Modification built into the heating volume 13. The remaining Components are the same as those in Fig.1 components shown, so here is another No need to describe contact zone 1. Through this big one Number of identical parts for two different ones Circuit breaker variants can be Make spare parts management particularly cost-effective.

5a shows a first structural detail of the Connection between the heating volume 13 and Arc zone of a circuit breaker according to the invention. The axial distance a between the caps 7 and 9 is by means of an openwork attached to these caps 7 and 9 Rings 38 made of a temperature-resistant insulating material replenished. The ring 38 can also on one of the caps 7th or 9 can be directly molded on. The ring 38, the one on the right Part of Fig.5a is shown in section, has a inner ring of webs 39, between which radial aligned openings 40 are arranged. An outer, spaced from the inner ring, ring of webs 41 between which radially aligned openings 42 are arranged, usually coaxially, the inner rim so that the webs 41 the openings 40 cover. This arrangement of the webs 39 and 41 brings the Advantage with it that the outgoing from the arcing zone Heat radiation, and also from the arc caused pressure waves, not directly into the heating volume 13 act and there may be too high pressure increases can cause.

5b shows a ring 38 which has two rows of distributed over the circumference and offset against each other Bores 43 and 44 is provided. These holes 43.44 each have an axis 45, 46, the axes 45 den Bores 43 and the axes 46 assigned to the bores 44 are. The axes 45 and 46 intersect in one Intersection 47, which lies on the central axis 2. Each of the axes 45 and 46 has an intersection angle α the central axis 2. The cutting angle α points preferably values in the range from 45 ° to 75 ° however, other values are also conceivable, especially must axes 45 and 46 do not have the same cutting angle exhibit. The cutting angle α of 65 ° has the present version of the circuit breaker as special proven favorable. The holes 43 and 44 are in this Execution cylindrical, but it is also possible to make these holes 43 and 44 conical, such as this is shown in Fig.5c. Bores 43 and 44 expand towards this in this version Heating volume 13 to, otherwise they are arranged the same as the corresponding holes in Fig.5b.

5d shows a ring 38 which has two rows of holes 43 and 44 distributed over the circumference are provided. These bores 43, 44 each have an axis 45, 46, the axes 45 the bores 43 and the axes 46 the Bores 44 are assigned. Cut axes 45 and 46 at an intersection 47, which is on the central Axis 2 lies. The axis 45 has one Intersection angle α with the central axis 2. The axis 46 each has an intersection angle β with the central axis 2 on. The intersection angle β is somewhat smaller than that Cutting angle α executed. This embodiment is then useful if the heating volume 13 is not symmetrical to Annular gap 36 is arranged. In the illustrated here Example is the part of the heating volume 13 that is to the left of Annular gap 36, or to the left of ring 38, is somewhat larger failed as the right part. The greater inclination of the Bores 44 facilitate the inflow of hot gas, so that the inherently unfavorable effects of the mentioned Asymmetry of the heating volume 13 at least somewhat compensated be what an improved filling and therefore a advantageously larger storage capacity of the heating volume 13 has the consequence.

Figures 6a to 6c show further constructive Design options for the direct connection between the heating volume 13 and the arc zone, and show they unwind the ring 38 with others in principle possible cross-sectional variants of the radial openings 42.

These openings 42 lead radially from the central axis 2 gone, they have comparatively small cross-sections. In usually the axes of the openings 42 are perpendicular to central axis 2 arranged, but it is possible to this Axes at a right angle Angle to cut the central axis 2. Here can different openings 42 of a ring 38th have different cutting angles. For the Fluidically favorable design of the openings 42 the tools of flow physics are available.

If no ring 38 is provided in the annular gap 36, it has proved to be particularly advantageous in terms of flow technology, form the annular gap 36 so that it is radial Direction expanded. If a particularly high hot gas pressure should be generated, the annular gap 36 is formed so that it tapers in the radial direction. They are one Many constructions of the annular gap 36 are conceivable, so that for each of the possible operational requirements optimal shape of the annular gap 36 can be achieved.

7 shows an example of the shape of the caps 7 and 9, the mutually facing end faces of which are chamfered here in such a way that the annular gap 36 widens in the direction of the heating volume 13. The cross section Q ₃ formed as a cylindrical surface at the narrowest point of the annular gap 36 will generally meet the following condition, in accordance with the respective operational requirements placed on the circuit breaker: Q 3rd Q 1 + Q 2nd = 0.8 ÷ 1.6

The area of the inner opening of the cap 9 is to be used as the cross-section Q ₁ at its narrowest point, and depending on the design of the contact basket 10, this narrowest point may also be in the region of the contact basket 10. The area of the inner opening of the cap 7 is to be used as the cross-section Q ₂ at its narrowest point, and depending on the design of the contact basket 8, this narrowest point may also be in the region of the contact basket 8. This condition formulated above is also advantageously taken into account when dimensioning the openings 40 and 42 and the bores 43 and 44 of the other design variants. The cross sections Q ₁ and Q ₂ are shown in different sizes in FIG. 7, as is quite possible with circuit breakers. The relationship given above also applies in this case.

With the circuit breaker variants described here an external nominal current path, which in the range of Contact zone 1 from the contact cylinder 15 via the contact fingers 16 and the nominal current contact tube 17 leads provided. For Circuit breakers designed for comparatively small rated currents or are only designed for short-term current loads, this nominal current path can be omitted, making this Circuit breaker variant is very cheap. In this Case would be the power track that is used in this design the contact zone 1, for example, from the holding part 11 via the Contact basket 10, the switching pin 3, the contact basket 8 and that Tube 23 would lead, at the same time the guidance of the nominal current take over.

It is also conceivable that, for example, the contact basket 8 a blow coil is connected in series. The through the Blow coil causes forced rotation of the arc 35 a higher pressure of the hot gas in the arc zone. This is particularly advantageous if the Circuit breakers for particularly low-current shutdowns is designed because of the rotation, the thermal Effect of the arc 35 is enhanced.

If the circuit breaker according to the invention for a comparatively small breaking capacity is designed, so can possibly on the heating volume 13th cooperating compression volumes 21 are dispensed with, so another cheap variant of the circuit breaker arises.

The figures are now used to explain the mode of operation a little closer. When you turn off, it always comes first the rated current path is interrupted, whereupon the cut-off current the power current path commutates. The switch pin 3 pulls then in the course of its switch-off movement between the Contact baskets 8 and 10 of the erosion contact arrangements 5 and 6 an arc 35. The length of the arc 35 will therefore essentially by the distance between the two contact baskets 8 and 10 determined, larger Fluctuations in arc length and related Fluctuations in the heating power of the arc 35 can this circuit breaker therefore does not occur, so that at the dimensioning of the heating volume 13 of one, only depend on the current current and therefore easy to take into account, heating power of the arc 35 can be assumed. The breaking capacity of this As a result, the circuit breaker can be compared simply calculate in advance so that the scope of the necessary Attempts at development and thus also the necessary ones Costs can advantageously be reduced.

The switch-off speed is selected so that the Arc 35 only briefly on the tip 4 of the Switch pin 3 burns. The tip 4 therefore hardly points Burn marks on. The contact baskets 8 and 10 are off especially erosion-resistant material, they show therefore a comparatively long service life. Of the Circuit breakers therefore only have to be used comparatively rarely be revised, making it a comparatively large Availability.

The arc 35 is because of the switch-off movement of the Switching pin 3 comparatively quickly its full length, which is essentially due to the distance between the two Contact baskets 8 and 10 is determined, so that the full shortly after the contact separation Arc energy is available for that Pressurization of the insulating gas in the area arranged between the erosion contact arrangements 5 and 6 Arc zone. The arc 35 impacts him surrounding insulating gas thermally and thereby increases briefly the pressure in the arc zone of the quenching chamber. The pressurized insulating gas flows through the annular gap 36 into the heating volume 13 and is stored there temporarily. However, part of the pressurized insulating gas flows on the one hand through the volume 30 into the arcing chamber volume 29 and on the other hand through the volume 31 into the Extinguishing chamber volume 29 from. In the nominal current contact tube 17 the piston-cylinder assembly built into their Compression volume 21 when the insulating gas is switched off is compressed. This compressed fresh insulating gas is generated in addition to the thermally pressurized insulating gas through the openings 19 in the heating volume 13 initiated.

However, this inflow only takes place when 13 in the heating volume the pressure is lower than that Compression volume 21. This is for example before Contact separation the case or before the zero current crossing of the Breaking current or when the arc 35 so Low current is that it does not intensify the arcing zone can heat up enough. However, heats a powerful one Arc 35 the arc zone very strongly, so that comparatively high pressure of the insulating gas in the Heating volume 13 occurs, so takes place at this high pressure initially no inflow in the piston-cylinder arrangement generated compressed gas. Will be in the heating volume 13 predefined limit value of the stored pressure exceeded, it opens after this is exceeded predetermined limit a not shown Pressure relief valve and the excess pressure is directly in the quenching chamber volume 29 is reduced. Will in Compression volume 21 a predetermined limit of Compression pressure exceeded, so opens after If this predetermined limit value is exceeded, pressure relief valve, not shown, and the excess Compression pressure is applied directly to the quench chamber volume 29 degraded into it. In this way, with great certainty prevents an inadmissible in this area Mechanical load capacity exceeded Components can occur. But it is also possible if the circuit breaker, for example, only for comparative small breaking currents is designed for this Dispense with pressure relief valves.

As long as there is overpressure in the arcing zone, there is current very hot ionized gas also by volume 30 and 31 into the quench chamber volume 29. The two gas flows form because of the similarly designed Flow cross sections similar, so that in the Arcing zone built up pressure approximately evenly and flows out to both sides in a controlled manner, so that the Heating volume 13 for extinguishing the arc 35 Existing hot gas can be stored under pressure for as long can until successful, leading to deletion blowing of the arc 35 can take place.

The outflow of the hot gas from the arc zone into the Volume 31 can be controlled using the switching pin 3 be because the annular discharge cross-section between the Switch pin 3 and the holding part 11 with increasing stroke of Switch pin 3 becomes larger. It is also possible to have the wall of the holding part 11, which limits the volume 31 radially, so train that, depending on the hub, the desired optimal discharge cross-section results.

In the circuit breaker according to the invention that is Heating volume 13 with the two erosion contact arrangements 5 and 6 rigidly coupled so that the heating volume 13 always same, usually even symmetrical to the annular gap 36 is positioned. During the entire shutdown process, So both during the heating phase and during the Blowing of the arc 35 changes at this position Nothing. The inflow of the hot gas into the heating volume 13 and also the outflow of the gas mixture from the heating volume 13 takes place during the blowing phase, because of the constant geometry, always in the same way, so fluctuations in breaking capacity caused by Flow instabilities in the area of the annular gap 36 of the Circuit breakers are caused not to occur can. The different flow-improving Measures in the area of the annular gap 36 allow one optimal adaptation of the circuit breaker to the am prevailing location of the switch Operating conditions.

The circuit breaker according to the invention is particularly for Switchgear suitable in the medium voltage range, it can however, if corresponding to the higher stress the dimension of the annular gap 36 and the distance between Contact cylinder 15 and nominal current contact tube 17 modified will also be used in high-voltage switchgear.

LIST OF DESIGNATIONS

1

Contact zone

2nd

central axis

3rd

Switching pin

4th

top

5.6

Burning contact arrangement

7

cap

8th

Contact basket

9

cap

10th

Contact basket

11

Holding part

12th

Insulating tube

13

Heating volume

14

Federation

15

Contact cylinder

16

Contact finger

17th

Nominal current contact tube

18th

Cylinder bottom

19th

Breakthroughs

20th

check valve

21

Compression volume

22

Compression piston

23

pipe

24th

Piston skirt

25.26

Sliding seal

27

Breakthroughs

28

check valve

29

Arcing chamber volume

30.31

volume

32

Baffle

33.34

arrow

35

Electric arc

36

Annular gap

37

Leading edge

38

ring

39

web

40

Breakthroughs

41

web

42

Breakthroughs

43.44

drilling

45.46

axis

47

Intersection

a

distance

α, β

Cutting angle

Q ₁ , Q ₂ , Q ₃

cross-section

Claims (17)

Circuit breaker with at least one quenching chamber, which is filled with an insulating medium and has a rotationally symmetrical design and extends along a central axis (2) and has at least one power current path, which has at least two quenching chambers arranged on the central axis (2) and constantly spaced apart from one another in the axial direction arranged, which delimits an arcing zone, has erosion contact arrangements (5, 6) which have a heating volume (13) connected to the arcing zone and a bridging contact which electrically connects the erosion contact arrangements (5, 6) in the switched-on state, the bridging contact along the central axis (2) extends centrally in the interior of the erosion contact arrangements (5, 6), and an annular gap (36) is provided between the erosion contact arrangements (5, 6), characterized in that that this annular gap (36) merges directly into a constant, annular heating volume (13) surrounding the erosion contact arrangements (5, 6), and that movable contact junctions located in the nominal current path are arranged in a region completely separated from the arcing zone. Circuit breaker according to claim 1, characterized in that the erosion contact arrangements (5, 6) are arranged inside a counter contact designed as a nominal current contact tube (17). Circuit breaker according to claim 1 or 2, characterized in that the heating volume (13) is operatively connected to a compression volume (21) in which the insulating medium is pressurized. Circuit breaker according to one of claims 1 to 3, characterized in that that the heating volume (13) is arranged concentrically around the erosion contact arrangements (5, 6), and that the heating volume (13) is arranged symmetrically or asymmetrically to the annular gap (36) in the axial direction. Circuit breaker according to one of claims 1 to 4, characterized in that that the heating volume (13) can be moved together with one of the erosion contacts. Circuit breaker according to one of claims 1 to 5, characterized in that the annular gap (36) is closed by means having openings which are provided for optimizing the flow conditions in this area. Circuit breaker according to claim 6, characterized in that the annular gap (36) is at least partially closed with a ring (38) made of an electrically insulating material, which has openings which are essentially radially oriented openings (40, 42) or bores (43, 44). Circuit breaker according to claim 6, characterized in that the ring (38) has an inner ring of first webs (39), between which radially aligned first openings (40) are arranged, and that, spaced from the inner ring, an outer ring of second webs (41) between which radially aligned second openings (42) are arranged, surrounds the inner ring so that the second webs (41) cover the first openings (40). Circuit breaker according to claim 6, characterized in that the ring (38) is provided with at least two rows of bores (43, 44) distributed over the circumference and offset with respect to one another, cylindrical or conical and having axes (45, 46), that the axes (45, 46) have a common intersection (47) lying on the central axis (2), and that the axes (45, 46) are inclined in opposite directions and each have the same intersection angle (a) with the central axis (2). Circuit breaker according to claim 9, characterized in that the cutting angle (α) is in the range from 45 ° to 75 °. Circuit breaker according to claim 6, characterized in that the ring (38) is provided with at least two rows of bores (43, 44) distributed over the circumference, having a cylindrical or conical design and having axes (45, 46), that the axes (45, 46) have a common intersection (47) lying on the central axis (2), and that the axes (45, 46) are inclined in opposite directions and have different intersection angles (α, β) with the central axis (2). Circuit breaker according to one of claims 6 to 11, characterized in that that a remaining cross section (Q ₃ ) of the openings of the annular gap (36) at the narrowest point of the annular gap (36) fulfills the following condition: Q 3rd Q 1 + Q 2nd = 0.8 ÷ 1.6, wherein the cross-section Q _{1 is} the area of the inner opening of the erosion contact arrangement (6) at its narrowest point, and the cross-section Q _{2 is} the area of the inner opening of the erosion contact arrangement (5) at its narrowest point. Circuit breaker according to one of claims 2 to 12, characterized in that that the bridging contact designed as a switching pin (3) and the rated current contact tube (17) can be moved in the opposite direction at the same or different speeds. Circuit breaker according to one of claims 2 to 12, characterized in that that the bridging contact is designed as a fixed contact and the counter contact with the rated current contact tube (17) as a movable contact. Circuit breaker according to one of claims 3 to 14, characterized in that means are provided in the heating volume (13) in the area of the connection to the compression volume (21) which improve the mixing between hot and fresh insulating medium. Circuit breaker according to claim 15, characterized in that at least one concentrically arranged baffle plate (32) cooperating with a check valve (20) is provided as the means which improves the mixing, and that the at least one baffle (32) is cylindrical or frustoconical, the central axis (2) forming the axis of the baffle (32). Circuit breaker according to one of claims 1 to 16, characterized in that that a blow coil is connected in series with at least one of the erosion contact arrangements (5, 6).

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