EP2630707B1 - Spark gap having a plurality of series-connected individual spark gaps, which are located in a stack arrangement - Google Patents

Description

The invention relates to a spark gap having a plurality of series-connected, stacked individual spark gaps, which are spaced apart by Isolierstoffscheiben and provided with a Federkontaktierung, the Einzelfunkenstrecken annular or disc-shaped electrodes, and further with controls to influence the voltage distribution over the stack assembly, according to claim 1.

In the known DC applications, the arc current must be forced to zero by increasing the arc voltage requirement to values greater than the available mains voltage (DC extinction principle). Starting from the generally known arc equation, in which the total arc voltage results from the sum of the anode / cathode drop voltage and the product of the arc length and arc field strength, different starting points for increasing the relevant arc voltage are obtained.

A particularly effective variant is the series connection of several partial arcs and thus the summation of the anode / cathode drop voltages. This physical principle of series connection of several spark gaps has already been used for medium-voltage arresters for a very long time. In the DE 395 286 is an arrester, consisting of two or more contacting, disc-shaped resistor bodies, described. Each resistor body has one or more ridges of significantly higher resistivity than the remainder of the disk. The height of the rib or ribs and thus the distance between the individual electrodes is between 0.02 mm and about 0.4 mm. Between the discs there are only a few points of contact that initiate the spark transition and the Spark discharge allows to spread quickly over the entire surface of the disc.

The ribs consisting of a material with increased resistivity are produced during the manufacture of the electrode discs, e.g. produced by oxidation. This manufacturing process is very expensive while maintaining the necessary tolerances. In addition, this arrester has no controls, so that the response and residual voltage is the sum of the individual values of the partial spark gaps and the desired requirements for a minimum residual voltage can not be met.

In the hitherto known stack arrangements without auxiliary devices for voltage control over the individual partial spark gaps, there was frequently a voltage overload and / or an undesirable response of the "weakest" element and thus a rapid failure of individual components or the entire arrester.

In order to prevent the above-mentioned failure phenomena, additional elements were later connected in parallel to such stack arrangements in order to homogenize the stress distribution over the individual partial spark gaps and thus to improve the arrester with regard to its response behavior. An arrangement with controls is eg in the WO 1982/00926 described. As a known state of the art, the parallel connection of linear, non-linear and / or capacitive resistors is presented here in order to achieve the most uniform possible voltage distribution over the individual partial spark gap, which are connected in series with one another.

As an alternative to a uniform distribution of voltage over the individual partial spark gaps is in accordance with the DE 737 825 as a coarse protection against overvoltages proposed a multiple protective spark gap for high voltage systems, characterized in that to achieve a highly curved course of the surge characteristic of the same, an auxiliary spark gap and an in-line impedance (capacitance, voltage-dependent or voltage-independent resistance) is provided, soft at least one the flashover paths of the protective spark gap is connected in parallel and the voltage distribution controls the rollover series in series such that at least at one of them a higher voltage value occurs than the voltage component assigned to it. The protective spark gap is subdivided into so many rollover distances that the operating frequency current flowing in response to the protective spark gap over the flashover gaps extinguishes automatically.

Further control possibilities by means of capacities or impedances are among other things from the writings CH 252 433 A . CH 210 132 A . DE 23 64 034 C3 and CH 215 001 A known.

When using the known stacking principle with the aid of controls for use in low-voltage systems, additional requirements must be observed, inter alia, with regard to the lightning current carrying capacity, the protection level and the size. For applications in low-voltage systems, the insulation coordination of the individual elements must be observed with each other, so that in this case a much lower level of protection than in medium or high voltage systems is required. Due to the lightning impulse withstand voltage of 10/350 μs, which is also required for low-voltage systems, the arrester must be dimensioned in such a way that the large specific energy occurring can be safely dissipated. In this case, no ribs made of material having a higher resistivity are applied to the electrodes as a spacer, but it is, as in the DE 1 256 306 B or US 2 298 114 described a stack arrangement of disc-shaped electrodes and insulating spacers used.

Such a stack arrangement consists of a sequence of disk-shaped electrodes with insulating rings, which each have a radial projection to the often consisting of graphite electrodes. The entire stack is braced by several guide rods in the axial direction by screwing. The guide elements or brackets are used for the radial positioning of the graphite discs and the insulation rings with each other, so that arise as reproducible supernatants for the outer flashover distances. The guide elements are in this case designed so that the radial tolerances of all disc electrodes or rings are observed and that the guides of the individual parts by the axial Bracing the stack does not lead to interruptions of the pressure chain, so leads to the formation of gaps or individual parts are damaged by the screwing. In addition to the formation of gaps, as a result of which an increase in the protection level due to the additional flashover stretches is unavoidable, incorrect clamping can also lead to breakage of the electrodes or to bending or shortening of the insulation projections. This type of positioning leads due to the unavoidable radial and axial tolerances, especially with increasing number of items to significant problems in the desired exact positioning of these elements with each other. This also applies to the exact compliance with the necessary projections between the insulation elements and electrodes. However, such displacements along the radial axis are hardly avoidable, even when new, because the pressure axis can act on the screw only over the sum of the entire stack. The number of feasible partial spark gaps is therefore greatly limited in the previously known embodiments.

If one also observes that according to their basic function of deriving impulse currents, all parts of the arrester are subjected to increased mechanical and thermal stresses, an i.A. first reversible and later irreversible loosening of the stack and thus displacement of the individual elements due to pressure waves, which are dependent on the height and number of loads, unavoidable. These disadvantages are exacerbated by the hitherto known subsequent spark plug embodiments, which leads to further thermal and mechanical loads on the arrangement.

In addition to the displacement also occurs an uncontrolled contamination of the insulation elements in particular of the radial projections in the outdoor area by the burned products. Due to the thermal stress in particular the insulation elements of the stack are damaged. The usual insulation rings made of PTFE tend, especially in such thermal stress and / or pressure, by the tension of the stack to flow. By this material properties also the compression of the stack is loosened, which can already cause gaps between the individual elements and thus takes place a further relaxation by uncontrolled, in particular radial, displacement of the individual elements.

In addition, as a result of mechanical and thermal loads, radial tears or complete cracks of the insulation rings can occur. These can lead to the emission of ionized gases into the outer insulation region of the stack arrangement or even to the removal of individual insulation paths by displacement of the insulation ring and thus to the short circuit of individual partial spark gaps. Even with insulation stretches of other materials such. Ceramic is due to the existing compression by the dynamic loads risk of cracking, which ultimately can occur analog failures.

Due to the space within standardized series housing and the type of stacking arrangement, the vertical and horizontal projections of the previously known arrester are already low anyway. At very steep rates of voltage rise, such as in subsequent strands or switching operations, it may already come to the outer arc of these arrangements with small projections. These partial or complete external flashovers of the insulation stretches of the stack can occur as a result of the already described and uncontrollable displacement and / or contamination effects in the previous solutions even at lower voltage gradients.
The previously known by the prior art control boards are attached by means of clamping contact on the graphite discs. Due to the displacement of the parts, by aging and sometimes also by burning, it comes here also to loosening or even the formation of gaps on these contacts, which inevitably leads to sparking at the transition to the control board. This, in the previous arrangements, unavoidable spark formation ionizes, in addition to the other effects, in addition to the immediate outer isolation region of the stack, whereby the already described critical external flashovers are additionally favored or directly ignited.

The sparking, however, not only leads to external arcing of the stack, but also to flashovers on the already flash-critical circuit boards on which the controls are arranged. These individual controls and the distances on the known printed circuit boards have in the current arrangements between the individual spark gaps not the necessary dielectric strength based on the total residual stress of Arrester, ie the voltage which can occur at most over the entire arrester. If it comes to steeper processes, the ignition delay of individual partial spark gaps, damage to individual insulation sections or components, the insufficient dielectric strength of individual components can be quickly exceeded. This can lead to overloading of the entire arrester.

Known from the CN 101090197 A is a stacked arrangement of individual electrodes for low voltage with electrical display and external control or ignition aids, in which the Steuerbzwad in the current path. Zündhilfe at least one fuse or a thermal fuse is provided. A calculation formula for the correspondingly necessary and equally large control capacities is given.

In addition, the current of the control or ignition aid and the temperature in the area of the control or ignition aid is monitored there. In this embodiment, however, there is insufficient thermal coupling to the affected components, so that only a limited assessment of the thermal state of the spark gap is possible.

Furthermore, the electrical display needs its own power supply, the additional components affect the function of the control or ignition aid and must be carried out even voltage resistant. Despite the various embodiments of the types of contacting a spark-free control can not be guaranteed secure and it is always the integration of an error-prone board necessary.

In the EP 0 905 840 B1 is presented a multiple spark gap with ohmic, linear or non-linear resistance circuit in which the first spark gap is formed and whose anode and cathode are spaced such that a relatively "low" operating voltage of, for example, a maximum of 4 kV is achieved. The chain of resistors preferably has logarithmically decreasing resistance values in the switching-through direction. Also there, the contact via contact springs to the electrodes, which preferably consist of cylindrical or cuboid, sharp-edged elements realized. Such an arrangement of Controls need to position the individual elements always an external board with the freely arranged contact springs. By this not always spark-free contacting all other partial spark gaps of the arrester can be affected and the controls should have sufficient dielectric strength. In addition, a complex construction and error-prone manufacturing is necessary in order to realize a suitable centering and thus compliance with the necessary clearance and creepage distances. The EP 0 905 840 B1 discloses the preamble of claim 1.

Also at the DE 101 14 592 A1 a calculation formula for the dimensioning of the control capacitors is proposed. In this case, a spark-current-carrying spark gap with a plurality of spark gaps connected in series is described, which are connected to impedances, in particular capacitances, so that the partial spark gaps are successively switched through. In this case, impedances with the same dimensions are used. Optionally, varistors can be assigned in parallel to the individual partial spark gaps in order to be able to maintain the required protection level even with negative follow-on strands. As an important basic functions of the arrester, the guiding and erasing of the follow-up current is described. To implement the described embodiment arranged on a board controls are used with insufficient contact.

Due to the disadvantages in the construction of known arresters and the uncontrollable aging, the usual and relevant in the standard test operating voltage of the arrester is only minimally affected. However, the relevant in practice for the protection of the system residual voltage of the arrester is almost uncontrollable, whereby a risk to the system can not be excluded. In addition to this disadvantage, the ratio between the response voltage and the residual voltage in the known arrester design is quite unfavorable and deteriorates more and more with increasing number of partial spark gaps.

The hitherto frequently used for DC applications spark gap technologies based on the Horn principle or extinguishing tube principle have the disadvantage that it comes in the connection of a surge current load technology-related always flowing to a net follower current. This current flow can not be avoided constructively, but only limited in time, as he Nevertheless, according to the DC extinguishing principle already described, all parts of the spark gap are subjected to thermal and mechanical loads during this period of time, leading to unavoidable aging of the arrester. In order to be able to realize a behavior that is as resistant to aging as possible over the given period of use, the constructions of such lightning current arresters must pay attention to these loads and the associated aging or burn-off, for example, of the insulating elements used.

In the case of the known products which are not designed to be flow-free, for example, the flow properties of cost-intensive PTFE as parting line material must be taken into account. Since this material is exposed to heat, e.g. through a flowing sequence flow and the, by the screwing of the stacking arrangement, constantly pending pressure plastically deformed and individual separation sections can be shorted thereby. Such impairment can not be detected and displayed by the insufficient thermal coupling possibly existing protection devices, so that at a renewed load the fused edges of the separation line material can tear off and thus no defined and possible gap-free transition between the two electrodes more given and the unwanted increase in the protection level unavoidable is.

From the above, it is therefore an object of the invention to provide a further developed spark gap with a plurality of series-connected, stacked individual spark gaps, which are spaced apart by Isolierstoffscheiben, which is characterized by a simple and fault-resistant construction and secure mounting and the above avoids mentioned disadvantages. The spark gap should be realized in folgestromfreier design and controlled by voltage-proof and electrically isolated from each other control impedances. The spark gap according to the invention should, in addition to safe functioning even when aging, also minimize the probability of the formation of a chain reaction of an external flashover of partial sections during high voltage gradients.

The object of the invention is achieved by a spark gap with a plurality of series-connected, stacked individual spark gaps according to the feature combination according to claim 1, wherein the dependent claims comprise at least expedient refinements and developments.

It should be noted at this point that the individual spark gaps each consist of two disk electrodes, which are spaced apart by an insulating disk. The disk electrodes are guided in an insulating body and each connected within this body via a spring contact with an integrated control. It follows that the individual partial spark gaps, which are connected in series, each consist of two insulating elements, each with an integrated disc electrode and by a Isolierstoffscheibe, e.g. made of vulcanized fiber, are spaced from each other. These, each between two disc electrodes or two insulating material arranged insulating disc forms by their circular recess on the one hand, the required distance or flashover distance for a corresponding spark gap and on the other hand, a sufficient supernatant in the edge region, to avoid unwanted outer flashover.

An insulating element each includes a disk electrode and spring elements for contacting the control element. About the spring elements, the control is connected in each case with the disk electrode and the guide element and is preferably enclosed on all sides by the insulating material. This can e.g. be realized by a pocket or even according to the later described embodiment by a film hinge. This quasi-enclosing integration of the control element in the insulating material and the partitioning of the contact connections with each other serves to reduce the risk of unwanted external flashovers.

The spark gap according to the invention, which is preferably usable for DC applications, is based on a known stack arrangement of individual electrodes with external potential control by means of impedances. The number of separation sections is selected so that the behavior of the spark gap when responding quasi folgestrom free up to the height of the maximum operating voltage. The construction of the spark gap is simple and inexpensive and modular to the respective low voltage level customizable. With the invention, the goal of a minimum residual stress and a simplified assembly process is achieved.

The necessary functional elements of the partial spark gaps, e.g. Graphite discs with controls and separation sections are designed as individual modules and kept free of the functional loads such as pressure, contraction and so on, resulting in an aging stability and high quality of the entire spark gap.

According to the invention, the annular or circular electrodes required to form one of the individual individual spark gaps are inserted into an insulating body and held centered by it, the respective insulating disk being located between the insulating bodies and being fixed by the latter. For receiving and centering the electrodes, a recess is provided in the insulating body whose shape is complementary to the contour of the respective electrode, wherein the recess has on the inner peripheral side at least partially yielding, resilient centering projections or centering noses. By the respective assignment of the controls and a suitable centering of the individual disc electrodes and the interposed Isolierstoffscheiben the shift of the functionally relevant individual elements with each other is avoided. As a result, a secure pressure contact of the individual partial spark gap elements and thus the total discharge function can be realized.

These centering projections or centering noses can be used in the manufacture of the insulating body, e.g. molded and formed by injection molding.

The respective insulation bodies have a radial projection or a corresponding projection, which receives at least one contact spring for a particular edge-side contacting of the respective electrode. The contact spring extends at least partially into the recess in order to ensure the desired contacting of the electrode.

The respective insulation body has, in particular in the region of the radial extension, a film hinge part which can be moved from an opening position into a closed position.

The film hinge member has at least one formation or opening for receiving at least one of the respective controls.

This shape or opening may have a different geometric shape for correspondingly different, confusion-held controls.

The at least one of the respective control elements is electrically connected via the at least one contact spring. Thermally and mechanically susceptible solder joints can be omitted.

At the radial extension of the insulating body, spaced from the contact spring, a receptacle for a further spring-like contact element is provided, wherein the distance and the position between the electrode distal end of the contact spring and the second contact element corresponds to the position of the terminals of the respective control.

In this case, the second contact element can extend into a recess space, which may be one of the elements connecting the stack arrangement, e.g. a rivet or a screw, takes up. As a result, a corresponding contacting and formation of the series connection of the stack arrangement is given in an easy manner.

According to the invention, a circumferential air gap between the respective electrode and the respective insulating body is provided by the centering by means of the centering projections or centering projections. This gap serves on the one hand as a pressure equalization chamber and forms an area for targeted, non-disturbing Berußung. If required, additional ventilation channels can be integrated within the structure.

In addition to the insulation body, bearing-securing projections and / or recesses which are complementary in each case on the upper and lower sides are formed, in particular formed, in the stack.

The Isolierstoffscheiben have an opening facing the respective electrodes opening to form a distance or separation distance. The same necessary outer insulation distance is ensured by a sufficient overlap in the edge region relative to the disc electrode.

In addition, in one embodiment, the Isolierstoffscheiben have an extension section with an adjustment recess, which also serves to secure the position in the stack composite.

In a preferred embodiment, the insulating disks each have a thickness of approximately ≦ 300 μm and consist, for example from a vulcanized fiber material.

At least parts or sections of the insulating body are made of a thermally conductive plastic material, so that the thermal energy generated in the rollover case can be safely and quickly dissipated to the outside.

The dielectric strength of the controls is greater than or equal to the maximum occurring protection level selected.

The impedance values of at least some of the respective controls are five to ten times greater than the longitudinal capacitance of the stack arrangement.

The insulation bodies can be at least partially color-coded in order to avoid confusion in relation to their arrangement in the stack arrangement and series connection.

In one embodiment of the invention, a thermally sensitive overload indicator, e.g. designed as Lottrennstelle, available.

The response voltages of the single spark gap are less than 1500 V. The aforementioned circumferential centering or centering, which represent in their capacity spring elements, the compensation in the event of pressure loads of the stack. In a further variant, it is possible to perform the controls and their contacting as inserts for an injection molding process.

The impedance values of the individual control elements can vary depending on the specific mechanical construction and / or with regard to the used Materials are dimensioned. As stated, the impedance value of the controls is five to ten times higher than the longitudinal capacitance of the array, with the impedance value of the last spark gap being on average again 5 to 10 times higher than that of the other controls. In the solution according to the invention, a ratio between residual and Ansprechstoßspannung smaller 2.5 is achieved.

For contacting to an external terminal, in a preferred embodiment, a so-called tox-clinching technology, i. used a clinching, possibly in conjunction with a tolerance compensation surface.

The invention will be explained below with reference to an embodiment and with the aid of figures.

Fig. 1

eine Prinzipdarstellung einer Stapelfunkenstreckenanordnung gemäß dem Stand der Technik;

Fig. 2a

und 2b eine Darstellung des erfindungsgemäßen Isolationskörpers mit Filmscharnier im geöffneten Zustand (Fig. 2a) und im geschlossenen Zustand mit noch nicht eingesetzter Elektrode (Fig. 2b);

Fig. 3

eine Darstellung eines Funkenstrecken-Überspannungsableitersteckteils mit einer noch nicht vollständig kompletten Stapelanordnung von Isolationskörpern mit den entsprechenden Elektroden und Isolierstoffscheiben sowie angedeuteten Verbindungselementen und

Fig. 4

eine Darstellung der kompletten Stapelfunkenstrecke mit Außenanschlüssen, die Steckkontaktflächen umfassen einschließlich einer Toleranzausgleichsfläche an einem der Außenkontakte.

Hereby show:

Fig. 1

a schematic representation of a stack spark gap arrangement according to the prior art;

Fig. 2a

and FIG. 2b shows an illustration of the insulating body according to the invention with a film hinge in the opened state (FIG. Fig. 2a ) and in the closed state with not yet inserted electrode ( Fig. 2b );

Fig. 3

a representation of a spark gap surge arrester with a not yet complete stacking arrangement of insulating bodies with the corresponding electrodes and insulating discs and indicated connecting elements and

Fig. 4

an illustration of the complete stacked spark gap with external connections, the plug contact surfaces include including a tolerance compensation surface on one of the external contacts.

To eliminate the disadvantages of the prior art, an aging-stable lightning current arrester in a folgestromfreie execution with at the same time low response and residual stress is proposed according to the invention. The functional elements of the partial spark gaps such as graphite disks, controls and separation lines are designed as individual modules and decoupled from other stresses such as pressure and Berußung and therefore not affected in this regard.

It is assumed in a folgestromfreien execution on the basis of the series connection of partial spark gaps with additional controls. It is thus obtained a Ablelter, in which it can not come to a flow of a follow current, even if there is a surge current load, since the existing reverse voltage of the spark gap is greater than the applied mains voltage at any time.

The folgestromfreie execution of the arrester according to the invention, there are several advantages. All essential elements are not exposed to a long-term load in the form of a follow-on current and thus are not unnecessarily thermally and / or mechanically loaded. By avoiding a follow-on current, important functional parts within the arrester can be adapted and dimensioned accordingly to the lightning current carrying capacity and the protection level.

A folgestromfreie embodiment is achieved by a correspondingly sized number of partial spark gaps in a series circuit. A single partial spark gap preferably consists of two disc-shaped electrodes and a spacer, for example in ring form of a high-resistance or insulating material.

By folgestromfreie execution and thus lower thermal and / or mechanical stress on the individual components, the material or the thickness for the respective separation sections can be chosen freely. By avoiding a follow-on current, in particular a thermal deformation or impairment of the separating line material in the edge region is avoided, since usually the follow-on electric arcs preferably form as a contracting arc in the edge region.

In a simple manner, electrodes are used without additional external insulation, the supernatants of the separating gap material being chosen to be sufficiently large in order to avoid flashovers of individual partial spark gaps and / or of the entire series connection.

Essential to the invention, the electrode may also be provided with a gap-free outer insulation, e.g. made of epoxy resin, technical glass or lacquer, in order to be able to reduce the required sliding and air distance within the arrester.

To comply with the normative requirements and the desire for the lowest possible response and residual voltage of the overall arrangement, the individual partial spark gaps are dimensioned so that the impulse response voltage is less than 1500 V. In order to be able to realize such small values, the distance between the two electrodes of the respective partial spark gaps is minimized. As a result of the sequence-current-free design according to the invention, the arrester and thus the individual electrode disks are predominantly loaded with pulse currents.
Such a pulse current arc usually forms diffuse and has several arc root points, so that there is no punctual overload, as in a follow-current arc, on the electrode surface. By means of the diffuse arc, for example, a sublimation of the graphite electrodes preferably used is avoided and smaller separation line thicknesses can be used without affecting the overall behavior of the arrester. In this case, electrode distances of less than 300 μm have proven to be particularly suitable.

In the solutions of the prior art, as based on the Fig. 1 shown in principle, electrodes 4 and insulating separation sections 3 are secured against each other by external guides 5 made of insulating material. This requires a complex construction with minimal tolerances, which among other things, the assembly is difficult.

On the outer guides of Isolatiomsmaterial the electrodes 4 are directly on, whereby these guides or the entire insulating holder and thus unavoidable sliding are exposed directly to a Berußung.

Such known arresters can be integrated into series housing, which often consist of a lower part 1 and a pluggable upper part 2.

The aforementioned Berußung and / or a thermal load is favored by entering subsequent streams in the prior art, which are used in particular for large voltage gradients and as a result of aging alternative sliding or rollover paths, so that the originally desired arrester function is only limited available.

Individual elements of the stack arrangement are held together by the outer guides in total and provided with separate control boards 6, which have a large error potential. Due to function-related pressure loads, e.g. during a lightning impulse current, with such a construction no exact position of the elements to one another and / or to the control elements can be guaranteed. The impulse loads lead according to the prior art in heavily strained and a nearly complete seal between the disc electrodes 4 and the insulation rings 3 in function of the arrester to an unnecessarily high pressure load. The uncontrolled blowing out of residues as a result of the arc erosion then leads to a direct and generally blanket coverage of the insulation rings, as a result of which the already low external rollover safety continues to drop.

As a result of a quasi-breathing of the stack during the load, ionized gas or plasma also passes uncontrolled into the outer area, which is particularly vulnerable to being blown over. So that the previous constructions find their way back into the initial state as often as possible even after loading with high pressures and late use of irreversible loosening of existing screw connections, relatively rigid and space-consuming constructions are required for fixing the screws. This leads to a higher space requirement. The outer terminal electrodes require due to the unavoidable in this construction tensions a thickness which is significantly greater than that is necessary for tension-free guidance exclusively for controlling the pulse currents. This also leads to a higher space requirement and an increased cost of materials. Due to the above-described defective construction, the selection of the parting material and its thickness is severely limited, thereby further reducing the available space within known housings for DIN rail mounted devices.

Previous screw connections have a screwing direction 7, which serves to keep the overall stack under a certain prestress. This screwing direction 7 is equal to the printing direction 7 as a result of the arc. By the same sense of direction, a loosening of the screw connection as a function of the load number is almost unavoidable.

Due to the effect of the pressure axis in the stacking direction, the expansion of the stack and the necessary dimensions for a stable holder construction the execution possibilities of the spark gap according to the prior art as a plug-in module clear limits, as the necessary insertion forces increase after several loads due to the widening of the construction or Also, the forcibly occurring tolerance compensation is taken into account, which is not the case with the inventive solution.

Through the use of contacting elements 8 made of spring material for the respective control elements, the individual electrodes 4 can be displaced by the unavoidable loosening between each other and / or with respect to the spacers held by the same guides, so that a sufficient distance is not always guaranteed and the Danger of external flashovers exists.

In the embodiment according to the invention, the separating sections or spacer rings and the electrodes of the individual partial spark gaps are reliably spaced apart, insulated and centered separately.

According to the representations after the Fig. 2a and 2b the centering is ensured by the use of an insulating element or insulation body 19 with a film hinge 9 for each electrode 12.

In a recess of the insulating body 19 are circumferential centering noses, e.g. designed as spring elements 10, which position the individual electrodes 12.

The film hinge 9 located on each insulation body 19 has openings which receive control elements 11, for example designed as surface-mounted components. It is thus in a preferred embodiment dispensed with a separate board for attaching necessary controls such as impedances, varistors and so on to exclude a related potential error.

Preferably used ceramic components as controls 11 can each be integrated directly into the film hinge 9. Contact springs 13, which are necessary for a secure contacting of the control elements 11 to the individual electrodes 12, but also to a reference potential, are inserted into the film hinge 9 and securely positioned and kept isolated.

By the circumferential spring elements 10 on the inside of the insulating body 19, the respective electrode 12 is pressed against the respective contact spring 13 and the associated control element 11, so that a spark-free contact is ensured and no prone solder joint is necessary.

By contacting over the circumferential, resilient, elastic, in particular spring elements 10 also partially elastic behavior is given to safely protect the ceramic controls 11 against any tension and compensate for pressure loads.

Through the use of the insulating body 19 with film hinge 9 is a very good overlap ratio to avoid slip and an optimal centering of the individual electrodes as shown Fig. 3 created.

The necessary spacing and thus electrical insulation between two successive electrodes 12, which are each centered in separate insulating bodies 19, is ensured by a spacer element or by separating sections in plate or disk form (reference numeral 14). The corresponding Isolierstoffscheiben 14 have a respective electrode 12 facing opening to form the distance or separation distance. The Isolierstoffscheiben may also have an extension section with an adjustment recess for receiving adjusting elements, such as rivets or screws 15.

Even with an unavoidable pressure load, e.g. due to a lightning surge current, resulting in a quasi-breathing of the stack assembly, the elastic and self-centering arrangement of the electrodes 12 and the insulating 14 and the respective assignment to the respective control element 11 and thus an intact Ableiterfunktion given a consistently low level of protection.

A possible Berußung on the insulating body 19 is only partially on the inner edge, with which the electrode 12 is directly in contact via the spring elements 10, partially possible. This Berußung is however at a preferred use of graphite as electrode material at this point unproblematic and does not lead to unwanted outer flashovers and thus not to an impairment of the arrester function.

By centering the individual electrodes 12 by the particular integrally formed centering lugs or spring elements 10, an almost circumferential air gap is provided, which may additionally accommodate Berußungspartikel, without resulting in a complete Berußung the inner edge or the outer edges of the insulation body.

Neither the vertical nor the horizontal separation sections are directly consumed, as the soot can escape into uncritical areas.

The circulating air gap can also serve as a compensation chamber at pressure increases due to the function-related loads. If required, further venting channels can be integrated into the individual elements such as electrodes and separating sections of the stack.

The Isolierstoffscheiben 14 are constructed so that they accommodate necessary for preliminary adjustment of the stack assembly, already mentioned screws or rivets as guide elements 15 and are sufficiently isolated by corresponding deflections within the insulating material in the longitudinal and transverse axis of other potential-related elements. Accordingly, direct sliding discharges are not possible by appropriately integrated deflections and the controlled Rußabscheidung on specially designed surfaces.

The separating element formed by the insulating material 14 realizes the necessary distance distance and a secure insulation of the successive electrodes 12, the associated controls 11 and the necessary contact springs. Preferably, here is an easy-to-manufacture punching element, e.g. made of vulcanized fiber of appropriate thickness.

Such a parting line material is still dimensionally stable even with the required small thicknesses of ≤ 300 μm and can be used well in production as well as during assembly. Such a material is dimensionally stable even under thermal loads and has only a low flow tendency. In addition, vulcanized fiber is crack-resistant and break-resistant under mechanical and thermal shock and extremely sensitive to mechanical stress in all axes.

By integrating the control elements 11 and the contact springs 13 into the film hinge 9 of the insulation body 19, the separate guidance and centering of the individual graphite disks in the electrodes 12 in this insulation body, the separate dimensioning and the positioning of the insulating material 14 to the graphite disk and the insulation body 19 can the mechanical clamping force to realize the functionally meaningful gap freedom between the electrode and the separation section are realized without the respiration of the parts in the function of the arrester to a shift of the individual elements, the carbonization of the separation lines or other damage.

The pressure load according to the invention can cause no damage to the compounds, the individual elements and the position of the parts with each other. Likewise, the unavoidable soot release and the release of ionized gas does not lead to undesirable flashovers on the relevant component or insulation paths.

Due to the proposed structure, which is independent of both axial and radial tolerances, a risk of damage to components even with any number of partial spark gaps is almost impossible. The construction according to the invention, which overcomes the constructive disadvantages of the prior art, allows the construction of stacked spark gaps with significantly more partial spark gaps (at least approx. 30%) with the same external space.

The increase in the number of partial spark gaps made possible by the construction according to the invention may increase the residual voltage of the spark gap. To avoid this, the connection between the geometrical capacities of the construction and / or the materials used is used. In the case of the embodiment according to the invention, a longitudinal capacitance of the arrangement is calculated with the separating line material preferably used, depending on the respective thickness and construction with respect to the individual partial spark gaps. As a control for a possible nonlinear voltage distribution over the entire series circuit then a capacitance value is used, softer at least 5 to 10 times greater than the previously determined longitudinal capacity. From the second to the penultimate partial spark gap, equally sized controls with the calculated capacitance value are used everywhere.

At least the last partial spark gap of the stack arrangement, the associated control capacity is again by a factor of 5 to 10 times greater than the other control capacities to provide a sufficiently large supply of energy at this point, so that the entire spark gap safely ignites and the residual voltage over a usual dimensioning with control elements of the same size decreases so that the required level of protection is always safely maintained.

The resulting longitudinal capacities are dependent on the separation section material used, their thickness and the overall construction, so that the optimally used controls are to be adapted to the respective new circumstances with changes in the construction.

A risk of overloading individual control elements is avoided by using elements with a dielectric strength, which preferably corresponds to at least the occurring protection level of the entire arrester.

With such a wiring of a stack spark gap with the help of controls is achieved that the ratio of the maximum occurring Residual voltage over the entire arrester and the normatively determined Ansprechstoßspannung is always less than 2.5. The spark gap including control is also dimensioned so that a failure of up to 10% of the partial spark gaps including or excluding the control in the application environment for the overall function of the arrester is not critical.

In the event of unpredictable loads, for example, outside of the specification range, where the individual elements or partitions are overloaded, the proposed structure of the stack assembly and / or the formation of the control elements will not require additional protection measures, such as e.g. a casting, a propagation of the spark, so a chain reaction and thus effectively prevents a total rollover.

For a simple and secure insertion of the arrester, the insulating body 19 used with film hinges 9 are different color coded and prefabricated as individual assemblies.

All controlled electrodes are distinguished by the color coding in an odd or even partial spark gap.

The first of the partial spark gaps, which is made passive, is inserted in a separate outer casing.

The last partial spark gap of the stack arrangement, which is controlled with an increased capacitance value, is again coded and marked by the other film hinges for the even or odd partial spark gaps with controls of the same size by a further color. In addition, a control is used in another thus also permissive SMD size.

The mutually e.g. color-coded insulating body 19 with film hinges 9 are stacked according to the desired voltage in the simplest way with the interposed Isolierstoffscheiben 14.

The insulating body 19 with film hinges 9 center the preferred disk electrodes 12 and, for example, by corresponding guide lugs and the preferably produced as a punching elements high-resistance or insulating distance or separation distance elements (insulating 14).

The stack arrangement is preferably adjusted by means of guide elements 15, wherein one of the two plug contacts 16 according to the illustration Fig. 4 via a so-called Toxverbindung, ie a clinching technology, contacted with the stack.

On the one hand, components without additional aids can be connected with the aid of such a tox compound. On the other hand, the tolerances that inevitably arise in such a stack construction can be accommodated by a tolerance compensation surface 20.

With an equivalent structure without modification or additional parts, the above allows a free choice of the number of partial spark gaps within the size specified by the outer housing. It is not necessary to adapt any plug contacts to be used, since these tolerances are not influenced by the opposite stacking direction and thus, even in the aged state, there is always good pluggability.

Due to the mentioned tolerance compensation and the centering of the electrodes, a rapid and cost-effective modification of the separating line material and / or the separating line thickness and / or the TrennstreckenanzahJ and thus an adaptation to other arrester requirements is possible.

In principle, there is the possibility of arranging the control elements even further below or offset from one another along the circumference of the electrode within the total conductor.

The integration of the controls in the insulating film hinge and the associated advantages additional space is created so that even at higher voltages pluggable solutions can be implemented as a modular device.

As an extension, it is proposed in one embodiment to form a temperature-dependent display in direct thermal contact with the disk electrodes 12.

In this case, it is assumed that the greatest temperature development in the middle of the stack arrangement and the corresponding ratios in terms of heat capacity and heat conduction of the surrounding components are taken into account. A thermally sensitive element 17 is positioned in the region of the termination electrode 18 in this regard.

If additional heat removal is necessary, e.g. also the insulating material be made of a thermally conductive plastic or ceramic. As the thermally sensitive element 17, e.g. a solder, wax or glue can be used. When the outer electrode reaches a temperature outside a predetermined operating range, e.g. by melting the thermally sensitive element, a preloaded indicator (not shown) is released. By means of the display, information about a thermal overload of the spark gap can be obtained directly or via a remote message.

In summary, it should again be noted that in order to ensure a reproducible and aging-stable response voltage of the partial spark gaps, it is necessary that there is a gap-free connection between the disk electrodes 12 and the respective insulating disk 14. This is achieved in that the disk electrodes 12 have at least the same thickness as the corresponding insulating body 19. This ensures that the axial pressure load is always built up over the Scheibenelektroöden 12 and the insulating material 14 and not over the insulating body 19. The clamping connection of the disc electrodes in the insulating material also fixed the disc neither axially nor in the radial position rigid. This guarantees an automatic functionally reliable alignment of the parts after complete assembly of the entire stack assembly even with a mounting error of the individual parts in the insulating element. This results in an advantageous, largely always given by always given axial tolerances of the individual components design or construction with the assurance of a gap-free contact and thus a reproducible low and age-resistant response voltage, at the same time measures to avoid the external arcing can be realized.

The above has been achieved by dividing the stack into a sequence of individual insulating disks and insulating bodies as well as integrating a respective disk electrode, a control element and the contacting means of the control element into an insulating body. The guide elements of the entire stack assembly ensure regardless of the number of sections and the tolerances of the individual elements always the necessary pressure connection between the disc electrodes and insulating.

The described embodiment with radial centering serves for better mountability and better fixation of the outer projections of the insulating disk as well as the inner recess of the insulating disk with respect to the disk electrodes. As a result, a cost-effective use of the electrode material and the insulating disk is achieved.

Claims (15)

1. Spark gap comprising a number of series-connected individual spark gaps which are placed in a stack arrangement, which are spaced apart from each other by insulating material discs (14) and are provided with a spring contact (13), the individual spark gaps including ring-shaped or disc-shaped electrodes (12), and further comprising control elements (11) for influencing the voltage distribution over the stack arrangement,
   characterized in that
   the ring-shaped or disc-shaped electrodes (12) required to form one of the respective individual spark gaps are each inserted into an insulating body (19) and held by same in a centered manner, with the respective insulating material disc (14) being located between and fixed by the insulating bodies (19), and that a recess is provided to receive and center the electrodes (12) in the insulating body (19), whose shape is complementary relative to the contour of the respective electrode (12), wherein the recess comprises on the inner circumference at least partially elastic, resilient centering projections (10) or centering noses.
2. Spark gap according to claim 1,
   characterized in that
   the respective insulating bodies (19) comprise a radial prolongation which receives at least one contact spring (13) for contacting the respective electrode (12) in particular at the edge, wherein the contact spring (13) projects partially into the recess.
3. Spark gap according to claim 2,
   characterized in that
   the respective insulating body (19) comprises a film hinge part (9), in particular in the region of the radial prolongation, which can be moved from an opened position into a closed position, wherein the film hinge part (9) includes at least one hole or opening to receive at least one of the respective control elements (11).
4. Spark gap according to claim 1 or 2,
   characterized in that
   at least one of the respective control elements (11) is electrically coupled through the at least one contact spring (13).
5. Spark gap according to claim 4,
   characterized in that
   at the radial prolongation, spaced apart from the contact spring (13), a receptacle for another spring-type contact element (13) is provided, wherein the distance and the position between the end of the contact spring (13) away from the electrode and the other contact element (13) corresponds to the position of the connections of the respective control element (11).
6. Spark gap according to one of the preceding claims,
   characterized in that
   the centering by the centering noses or centering projections (10) provides for a circumferential air gap between the respective electrode (12) and the respective insulating body (19).
7. Spark gap according to one of the preceding claims,
   characterized in that
   complementary position-securing projections and/or recesses are formed, in particular integrally formed, on the insulating bodies (19) on the upper and lower sides in the stack.
8. Spark gap according to one of the preceding claims,
   characterized in that
   the insulating material discs (14) include an opening pointing to the respective electrodes (12) to form a distance gap or isolating gap.
9. Spark gap according to claim 8,
   characterized in that
   the insulating material discs (14) include an extension section with an adjustment recess.
10. Spark gap according to one of the preceding claims,
    characterized in that
    the insulating material discs (14) each have a thickness of substantially ≤ 300 µm.
11. Spark gap according to one of the preceding claims,
    characterized in that
    at least parts or sections of the insulating body (19) are made of a thermally conducting plastic material.
12. Spark gap according to one of the preceding claims,
    characterized in that
    the electric strength of the control elements (11) is greater than or equal to the maximally occurring protection level.
13. Spark gap according to one of the preceding claims,
    characterized in that
    the impedance value of at least some of the respective control elements (11) is five to ten times greater than the longitudinal capacitance of the stack arrangement.
14. Spark gap according to one of the preceding claims,
    characterized in that
    the insulating bodies (19) and/or the film hinge (9) are at least partially color-coded.
15. Spark gap according to one of the preceding claims,
    characterized in that
    a thermally sensitive overload indicator is provided.

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