EP0860918B1 - Overvoltage arrester device - Google Patents

Abstract

The overvoltage protection system has a pair of electrodes Ä1,2Ü set a distance apart within a housing Ä3Ü and these are connected to cables Ä4,5Ü. The housing has an opening Ä6Ü. When a voltage is applied to the electrodes the local air is ionised and an arc occurs and warms the ionised gas which then flows out of the opening and in doing so cools.

Description

The invention relates to a surge arrester comprising two spaced apart electrodes arranged from one another, forming an approach point, and an electrode Housing, which by means of a perforated partition in two rooms is divided, with the electrodes in the first end region of the room in the first room lying approach point are arranged and the second room with at least one Outflow opening for ionized gases formed by between the electrodes Arcs are generated, provided and the two rooms along their entire Extension are arranged in layers next to each other.

Such a discharge device becomes parallel to the ones to be protected against overvoltages Circuit components switched, i.e. the first electrode is connected to the lead that second electrode connected to the derivative of the circuit concerned.

The two electrodes are at a defined distance from one another, which is from voltage applied to the electrodes is penetrated, provided that this is impermissible high value determined by the size of the electrode spacing. Subsequently An arc arises between the two electrodes, which connects the electrodes and thus and arrester of the circuit connects to each other with relatively low resistance. This will make the voltage between the supply lines to a compared to the The amount of overvoltage is reduced and the energy of the overvoltage is reduced Heat converted.

However, this means that the gases in the vicinity of the arc are strong are heated up and ionized and subsequently expand considerably. To one of them To avoid the resulting destruction of the arrester housing, this is with an opening, through which the heated gases can escape.

In this way, the housing of the discharge device itself can be destroyed protected, however, the gases now escaping can be used in the immediate vicinity Arrester arranged objects, i.e. those in the control cabinet next to the arrester Damage the existing switch or the control cabinet wall thermally.

US-PS-2 329 219 discloses a surge arrester according to the preamble of claim 1 and shows a spark gap comprising two electrodes which are fixed to plugs. These plugs are inserted into the end faces of a tube so that the electrodes are spaced apart from one another within the tube. Surrounding the tube is a second tube, the end faces of which are closed with the exception of one outlet opening. Slits are made in the wall of the tube. Due to this construction, US Pat. No. 2,329,219 comprises a first space containing the electrodes (formed by the interior of the first tube); a second second space provided with an outflow opening (formed by the area between the second and the first tube) and a perforated partition between said two spaces (formed by the slotted wall of the first tube).

FR-A-818 629 describes a spark extinguishing chamber or gas discharge device of a switching device. The contact pair of each pole section is here in its own

Extinguishing chamber arranged, these quenching chambers are housed in a self-contained housing. This housing is surrounded by a hollow cuboidal cap, which is somewhat larger than the housing. The spark quenching chambers have openings which open into the space between the housing and the cap, which space is divided into several chambers by means of the partition walls. In the area adjacent to the closed housing, the cap has an outlet opening for the ionized gases generated within the quenching chambers, which must take the path symbolized by the arrow in FIG. 1 of FR-A-818 629 .

To the mentioned damage caused by the hot ionized gases avoid the switches adjacent to an arrester could be made sufficiently robust or a sufficiently large distance between arresters and other components be left; however, both measures would entail a great deal of extra work - unduly large control cabinets or special switches with you.

It is an object of the invention to provide a surge arrester of the type mentioned at the beginning Specify the way in which the problems of thermal damage listed in objects located in the vicinity of the discharge device are avoided.

According to the invention this is achieved in that the openings only in second end region of the first space facing away from the approach point and that the outflow opening in the area of the second room is arranged.

With this design, the ionized gases must cover the entire Flow through the longitudinal dimensions of both rooms before they reach the outside, with which the ionized gases experience particularly efficient cooling.

The partition between these two rooms is one of the ionized gases obstacle to be flowed through, in which thermal energy can be dissipated.

The layering of the two rooms side by side is due to the following Considerations particularly advantageous: The overall height of a control cabinet device is in the Contrary to its width usually specified. By the one hit here The two structural units can be arranged side by side between the spark gap and the chamber Extend the spark gap and cooling chamber over the entire height of the arrester, this results in a particularly long flow path for the ionized gases and on the other hand the possibility of making the electrodes large and robust.

In a further development of the invention it can be provided that within the room Flow control devices are provided.

This enables the path to be covered by the ionized gases within the housing be extended, whereby a stronger cooling can be achieved.

In this context it can further be provided that within the room of the ionized gases to flow around baffles and / or sieves to be flowed through are.

Such components also contribute to increasing the cooling effect of the chamber.

It has proven to be advantageous that the flow control devices, baffle walls and Sieves are made of plastic.

The guide devices, baffle walls and screens can thus be made in one piece with the housing run, which is particularly advantageous for the inexpensive manufacture of the Arrester affects.

Alternatively, it can also be provided that the flow control devices, Baffle walls and screens made of a metal, e.g. Copper, iron or the like are formed.

Metals have a good thermal conductivity and absorption capacity, which means that the named Components such as cooling fins act and ensure particularly effective heat dissipation.

In a further embodiment of the invention it can be provided that the electrodes on spark gap connecting the approach point, e.g. Horn spark gap exhibit.

With such a spark gap, the arc ignited in the approach point quickly moved away from this, causing thermal damage in this area can be largely avoided. This also keeps the distance between the two electrodes unchanged after several derivations, which means that it remains the same Response voltage of the spark gap is guaranteed.

In this connection it can be provided that the electrodes at least in the area the spark gap made of copper, iron, copper coated with iron, sintered tungsten-iron or tungsten-copper composite or the like. Or from combinations of these Materials are formed.

Such materials have a sufficiently high electrical conductivity at the same time good temperature resistance.

Furthermore, it can be provided that at the end opposite the approach point the spark gap at least one, at least in the space delimited by the electrodes protruding electrode element, preferably arranged entirely in this space, such as. Plate, is arranged.

The arc running along the spark gap is caused by such electrode elements severed, i.e. converted into a series connection of several arcs. The The maintenance voltage of such arcs is much higher than that of one Single arc, so that the normal supply voltage no longer burn can leave and thus usually the subsequent follow-up currents of the overvoltage can be limited and interrupted.

According to a particularly preferred embodiment of the invention, that the first electrode is rigid and the second electrode is fixed movably in the housing, that in the approach point an intermediate film lying on the first electrode is arranged and that the second electrode by means of an elastic member, such as. Feather, is movable in the direction of the first electrode and can be pressed against the intermediate film.

After the thickness of the intermediate film can be manufactured very precisely, this arrangement can be used an exact electrode spacing independent of manufacturing tolerances and thus the height the ignition voltage can be specified relatively accurately.

In addition, such an arrangement can reduce the risk of the Arc from the deionization chamber formed by the electrode elements into the Proximity of the spark gap can be reduced; besides the running away of the Arc promoted from the approach point into the deionization chamber.

In a further embodiment of this embodiment of the invention it can be provided that the elastic component is formed by a coil spring.

This type of spring can exert a relatively large force on the second electrode be, which allows a reliable pressing of the electrode on the intermediate film.

Fig.1 eine besonders einfach ausgeführte Überspannungsableiteinrichtung im Grundriß in geschnittener Darstellung;

Fig.2 eine zweite Ausführungsforms, ebenfalls im Grundriß in geschnittener Darstellung;

Fig.3a die Funkenstrecke einer besonders bevorzugten Ausführungsform der Erfindung im Aufriß;

Fig.3b die von den ionisierten Gasen zu durchströmende Kammer der Ausführungsform nach Fig.3a im Aufriß und

Fig.4 den Schnitt A-A durch die Ausführungsform nach den Fig.3a,b.

The invention is explained below with reference to the preferred embodiments shown in the drawings. The individual drawing figures represent the following:

1 shows a particularly simple surge arrester in plan view in a sectional view;

Figure 2 shows a second embodiment, also in plan view in section;

3a the spark gap of a particularly preferred embodiment of the invention in elevation;

3a shows the chamber to be flowed through by the ionized gases of the embodiment according to Fig.3a in elevation and

4 shows section AA through the embodiment according to FIGS. 3a, b.

The surge arrester according to Fig.1 comprises two electrodes 1 u. 2 that are arranged at a distance from one another in a housing 3. At these electrodes are 1,2 The supply and discharge of the front via only symbolically illustrated supply lines 4, 5 impermissibly high overvoltages connected to the protective circuit.

In the example shown, a cuboid housing 3 was used, except for the Opening 6 and other openings, not shown, for the supply lines 4,5 in themselves is closed, but for the purpose of clearer representation parallel to the image plane was cut.

If the voltage applied to the electrodes 1, 2 is high enough, the voltage in the Proximity point 7 is ionized air and it comes to further Formation of an arc between the two electrodes 1, 2. That arc now warms its surroundings so that it can form hot ionized gases comes within the housing 3, which can flow out through the opening 6 to the outside.

It is provided that said opening 6 at some distance from the two Arrange electrodes 1, 2 so that between electrodes 1, 2 and outflow opening 6 there is a chamber 8 through which the ionized gases must flow. The size the opening 6 is expediently to be chosen so large that the gases are sufficient can flow out quickly, i.e. that there is no impermissibly high, the destruction of the housing 3 causing excess pressure to build up inside the housing. Instead of the only one Outflow opening 6 can of course also have a plurality in order to achieve this goal step out of openings.

The approach point 7 formed by the electrodes 1, 2 is in the first end region the chamber 8 is arranged, the outflow opening 6 is located in the second end region thereof Chamber 8. The ionized gases must therefore cover the entire length of chamber 8 flow through.

When flowing through said chamber 8, the ionized gases in them cool They indicate stored heat via the chamber atmosphere and the housing walls the environment, so that it only a relatively small amount when it emerges from the opening 6 Have energy content.

The extent of the cooling of the ionized gases depends directly on the length of the path they must travel within the chamber 8 together. To this path length too influence, are in the embodiment of Figure 2 within the chamber 8th Flow guide devices 9 are provided. They are platelet-shaped and so arranged to direct the ionized gases along a meandering path. This The path is now significantly longer than that in FIG. 1 from the approach point 7 to the opening 6 leading path, whereby in the embodiment according to Fig.2 a significantly stronger Cooling of the gases is achievable.

Another option is to increase the length of time that the ionized gases remain in chamber 8 extend, is the provision of flow obstacles, such as baffles 10 or Seven 11 inside the chamber 8. These can, however, in combination with one another can be provided alone.

The material of the baffle walls 10, sieves 11 and the guide devices 9 is in principle free selectable, but must be able to withstand the thermal stresses explained. As The simplest variant is the baffle walls 10, sieves 11 and guide devices 9 as To form the housing walls so that they are made of the housing material, an electrically insulating plastic.

Another option is to use metals such as To use copper, iron or the like, since these materials are good heat conductors and have heat storage capacity, whereby the gases flowing around them are cooled even more effectively.

In contrast to FIG. 1, the housing interior of the exemplary embodiment according to FIG. 2 is not made in one piece, rather a partition 12 is provided which divides the housing 3 into two Rooms 13 and 8 divided. In the first room 13 are the two already described Arranged electrodes 1,2, which are shaped here so that they are an approach point 7 and form an adjoining horn spark gap 14. Once in a time Approach point 7 arcing is caused by the acting on it, from Current flow through the electrodes 1, 2 and the magnetic forces caused by them moves along the horn spark gap 14, which is a widening and ultimately a Tear off the arc. The hot ionized gases generated in room 13 can through openings 15 of the partition 12 in the room 8, which is described Cooling chamber forms, overstepping.

The electrodes 1, 2 can be described here as in all the others Embodiments of any materials that have sufficient electrical Have conductivity, be formed. As particularly preferred materials for the Area of the spark gap 14 copper, iron, copper coated with iron, a sintered Tungsten-iron or tungsten-copper composite or the like can be specified. there combinations of these materials are also possible, which electrodes 1, 2 can have different materials in some areas.

3a, b and 4 is a particularly preferred one, already for installation in a control cabinet suitable embodiment of the invention shown. As best seen in Fig.4, here the two rooms 13 and 8 are arranged next to each other in layers. In the 3a spark gap 14 shown in plan comes to lie parallel to chamber 8, the resulting assembly thus has one with a multi-pole Miniature circuit breakers of comparable construction, in which the individual pole sections in be juxtaposed in the same way.

The housing 3 required for this again has a partition 12 with openings 15 on the first surface 121 on the left in FIG. 4, the chamber 8 with its Guide devices 9 and optionally baffles 10 and sieves 11 is constructed. At the the second surface 122 on the right in FIG. 4, the spark gap 14 is arranged. Both For operation, rooms 13, 8 must of course also be parallel to the image plane of FIGS. 3a, b running lids are closed, but not for the sake of clarity were shown.

The spark gap 14 used in this exemplary embodiment is analogous to FIG Horn spark gap configured, in addition here are the approach point 7 opposite end of electrode elements 16 provided in the of the electrodes 1,2 limited space protrude at least, but preferably entirely within of this room.

In their shape, the electrode elements 16 are not bound to any specifications in order to be able to narrow space between the electrodes 1, 2 as many such electrode elements 16 as possible to accommodate, they are designed as parallel plates. Through this Electrode elements 16 will "cut" the arc into a plurality in series partial arcs switched to one another, which leads to faster extinguishing of the Arc is.

The use of electrodes 1, 2, which at their approach point 7 Having a spark gap 14 in the form of a horn spark gap is a preferred one Embodiment represents, but can also with a housing structure according to Fig.3a, b and 4 any other electrodes 1,2 are used.

As in FIG. 1, the approach point 7 formed by the electrodes 1, 2 is in the first End region of the first room 13 arranged. As can be seen in particular in FIGS. 3a, b, the two rooms 13, 8 lie alongside one another in layers along their entire extent. In addition, it is provided that the openings 15 of the partition 12th exclusively in the end region of the first room 13 facing away from the approach point 7 are arranged and that at the same time the outflow opening 6 in the approach point 7 adjacent area of the second room 8 is provided.

This type of arrangement of openings 15 and outflow opening 6 means that ionized gases first the entire longitudinal extent of the electrode space 13 and then flow through the entire longitudinal extent of the gas cooling space 8. So that will despite the small geometric dimensions of the housing 3, a particularly long residence time of the ionized gases in the housing 3 reached. During this dwell time, the ionized gases cover a relatively long way, on which they cover large areas with the Housing 3 and the guide devices 9 come into contact.

The cooling of the ionized gases to be achieved in accordance with the invention task is thereby achieved to a particularly large extent.

The actually resulting electrode distance in the approach point 7 depends directly from the manufacturing tolerances that always occur with electrodes 1, 2 and housing 3. In order to the actual ignition voltage of the spark gap - which is directly dependent on Electrode distance depends - can only be specified relatively imprecisely.

In order to remedy this disadvantage, the invention provides for the first electrode 1 to be rigid To define housing 3, the second electrode 2, however, to a small extent to move hold. Furthermore, there is an elastic component 18 which, according to FIG. 3a, is designed as a helical spring is provided, which presses the second electrode 2 in the direction of the first electrode 1.

In the approach point 7, an intermediate film 17 is in contact with the first electrode 1 arranged. Due to the explained elastic component 18, the second electrode 2 is now on said intermediate film 17 pressed so that the actual electrode distance alone from the The thickness of this intermediate film 17 is independent of the manufacturing tolerances of the electrodes 1, 2 or of the housing 3- is determined. After the intermediate film 17 with a very accurate predeterminable thickness can be produced, the predetermined electrode distance can now can be realized much more precisely.

Although this type of adjustment of the electrode distance is only shown in Fig.3a , this can also be the case with differently designed electrodes 1, 2, for example electrodes 1, 2 as shown in Fig. 1,2.

Claims (10)

1. Overvoltage arrester device comprising two electrodes (1, 2) arranged spaced apart from one another and forming an approach point (7), and a housing (3) which is subdivided into two spaces (13, 8) by means of a partition (12) provided with openings (15), wherein the electrodes (1, 2) are arranged in the first space (13) with the approach point (7) being located in the first end region of the space (13) and the second space (8) is provided with at least one outflow opening (6) for ionized gases which are generated by arcs formed between the electrodes (1, 2) and the two spaces (13, 8) are arranged lying next to one another in the manner of layers along their entire extent, characterized in that the openings (15) are arranged exclusively in the second end region, facing away from the approach point (7), of the first space (13) and in that the outflow opening (6) is arranged in the area of the second space (8) adjacent to the approach point (7).
2. Overvoltage arrester device according to Claim 1, characterized in that flow guiding devices (9) are provided within the space (8).
3. Overvoltage arrester device according to Claim 1 or 2, characterized in that baffles (10), around which the ionized gases are to flow, and/or screens (11), through which the ionized gases are to flow, are arranged within the space (8).
4. Overvoltage arrester device according to Claim 2 or 3, characterized in that the flow guiding devices (9), baffles (10) and screens (11) are formed of synthetic material.
5. Overvoltage arrester device according to Claim 2 or 3, characterized in that the flow guiding devices (9), baffles (10) and screens (11) are formed of a metal such as, e.g. copper, iron or the like.
6. Overvoltage arrester device according to one of the preceding claims, characterized in that the electrodes (1, 2) exhibit a spark gap (14) such as, e.g. a horn spark gap, which adjoins the approach point (7).
7. Overvoltage arrester device according to Claim 6, characterized in that the electrodes (1, 2) are formed of copper, iron, iron-coated copper, sintered tungsten-iron or tungsten-copper composite material or the like or, respectively, of combinations of these materials, at least in the area of the spark gap (14).
8. Overvoltage arrester device according to Claim 6 or 7, characterized in that at least one electrode element (16) such as, e.g. a plate, which at least protrudes into the space delimited by the electrodes (1, 2) and is preferably wholly arranged within this space, is arranged at the end of the spark gap (14) opposite to the approach point (7).
9. Overvoltage arrester device according to one of the preceding claims, characterized in that the first electrode (1) is mounted rigidly and the second electrode (2) is mounted moveably within the housing (3), in that an intermediate foil (17) resting against the first electrode (1) is arranged in the approach point (7) and in that the second electrode (2) can be moved in the direction of the first electrode (1) by means of an elastic component (18) such as, e.g. a spring, and can be pressed against the intermediate foil (17).
10. Overvoltage arrester device according to Claim 9, characterized in that the elastic component (18) is formed by a helical spring.

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