EP3270474B1 - Spark gap arrester - Google Patents

Description

The invention is based on a separating spark gap as potential equalization device with a first electrode having a first connection part, a second electrode with a second connection part, a spark gap arranged between the electrodes, and an insulating material housing surrounding the components composed of these components, from which the connection parts protrude or abut to which the connection parts are accessible.

Spark gaps are used, for example, to equipotential bonding between components that carry different electrical potential. For example, at a coupling point of pipes which are connected to each other and separated by an electrically insulating gasket, such a spark gap is used, which is connected with a first connection part to the end of a first pipe and with the second connection part to the end of a second pipe becomes, so with existing ones Potential differences a potential equalization over the spark gap can be done.

Conventionally, such separating spark gaps are equipped with a pin-shaped electrode, over which, in the event of a voltage event, ignition of the separating spark gap takes place in order to bring about potential equalization. Such spark gaps are subject to constant wear with multiple loads, which leads to the fact that the distance of the electrode from the corresponding mating contact device changes, so that the overall behavior of the spark gap changes. From the DE 69828487 T2 different spark gaps are known with mutually facing electrode surfaces. Similarly, this is in the DE 494333 A specified.

From the EP 1 995 87 A2 Spark gaps are known with electrodes having a graphite coating.

From the US 2002/0171992 A1 spark gaps are known in which the electrode surfaces have elevations and depressions.

From the US Pat. No. 3,408,525 a spark gap with plate-shaped electrodes according to the preamble of claim 1 is known.

Based on this prior art, the present invention seeks to provide a spark gap, which can comply with today's standards, in which the threshold voltage is low at the Response to conventional forms is improved and also the insulation behavior. In addition, a compact space as possible to be achieved. Finally, an enrichment of the prior art should be achieved by a new solution.

To achieve this object, the invention proposes that each electrode has a flat rectangular contact area and a unilaterally projecting from this connecting part, both electrodes are insulated from each other with their contact area stacked on each other and between the electrodes two substantially flat rectangular graphite electrodes are arranged by a frame-like insulating film are spaced from each other, and that the facing surface areas of the graphite electrodes mutually parallel protruding strips and grooves between the strips, wherein the long transverse edges of the strips of the surface areas of the graphite electrodes are at least slightly offset from each other so that each edge of a transverse edge of a strip a first graphite electrode is opposite to a groove of the second graphite electrode.

The flat-rectangular design of the contact regions of the electrodes and the corresponding flat-rectangular shaped graphite electrodes, a compact spatial form is achieved. The rectangular shape is used to minimize size. For round designs, the design would be considerably larger, which is undesirable. Due to the arrangement of the graphite electrodes, by the Isolating film are spaced apart, and have on the facing surface areas projecting strips and past grooves and the staggered arrangement of the grooves and strips of a graphite electrode to the grooves and strips of the other graphite electrode, the response is improved because the long transverse edges of the strip Edges are formed, which are not aligned with the edges of the other graphite electrode aligned, but in each case in the groove of the other graphite electrode, and it is also achieved that the response voltage is relatively low. Also, the insulation behavior is improved. Prolonged start-up counteracts a deterioration in the ignition behavior of the spark gap, since even if some edges are rounded off due to several active cases and rounded, more edges for ignition remain.

In order to ensure a cost-effective construction of the device, it is provided that both electrodes have identical shape and are stacked in opposite directions rotated by 180 °, wherein the connecting parts protrude in opposite directions at the ends of the thus formed component.

The electrodes with the corresponding provided at one end connecting parts are identically shaped and are rotated in the design by 180 ° and turned stacked, so that with one and the same component, which is provided in a double arrangement, the corresponding device can be realized.

In addition, it is provided that the electrodes are zamak castings whose contact surfaces resting against the graphite electrodes are preferably nickel-plated.

The production as a zamak casting is inexpensive and easy to carry out, wherein preferably the inside of the electrodes against which the graphite electrodes abut are nickel-plated in order to ensure a good electrical contact between the electrode and the graphite electrodes.

In order to combine the electrodes to form a structural unit, it is provided that the electrodes are connected to one another by connecting screws, the shaft of which passes through the graphite electrodes, the head of the connecting screw and its shank in the penetration area through an electrode and through the graphite electrodes by means of a flange-provided insulating sleeve the electrode and the graphite electrode is electrically insulated and the shaft end is screwed into the opposite electrode.

The electrodes and also the graphite electrodes are perforated in overlapping areas so that connecting screws can be made through these perforations. For the purpose of isolating the connecting screws, which are usually made of metallic material, an insulating sleeve is arranged on the shank of the connecting screw, which has a flange, against which the head of the connecting screw and thus isolated from the electrode. The Isolierstoffhülse also insulates the screw relative to the first electrode to which the head rests with the interposition of the flange and isolated the possible contact area to the graphite electrodes. Only the shaft end of the connecting screw is screwed into the opposite electrode without insulation. A contact via the connecting screw is thus excluded. The arrangement of two such connecting screws, which are distributed over the length of the component, a secure and firm connection of the items is achieved in the mounting target position.

The insulating sleeve preferably consists of POM material, that is to say a polyoxymethylene. Such materials have high rigidity, low coefficient of friction, excellent dimensional stability and thermal stability while also having good dielectric properties.

The graphite electrodes, as the name implies, consist essentially of graphite. However, it is also possible to use other correspondingly conductive materials, but graphite is preferred as the base material.

Since the graphite electrodes must be installed in the mounting target position in a different orientation, in which the projecting from the respective areas strip areas are offset from each other, it is provided that the graphite electrodes at a corner of their flat rectangular shape a Coding contour, in particular a Eckabflachung or bevel, have.

As a result, a visual aid and also mechanical assistance is provided during assembly in order to ensure the correct installation without confusion.

Both graphite electrodes can have identical spatial form, whereby they ensure a staggered arrangement of the strips by the opposing mounting, which is desirable.

In order to also enable a positioning aid for the insulating film relative to the electrodes, it is provided that the frame-like insulating film on at least one transverse edge edge has a projection and the electrodes in the peripheral edge adjacent region have a matching recess into which the projection is inserted in mounting target position ,

The insulating film is placed in a suitable manner on the corresponding electrode, so that the preferably off-center edge provided projection is inserted into the matching recess arranged, whereby the correct positioning is achieved in the assembly target position and the Montierende this can easily recognize.

Preferably, it is also provided that the insulating film consists of aramid paper.

In addition, it is preferably provided that the graphite electrodes have a number of more than five strips and less than fifteen strips.

The number of strips and grooves is dependent on the size of the graphite electrodes, with a number of about 10 to 12 strips having been found to be particularly suitable for a suitable design.

Preferably, it is also provided that the graphite electrodes have on their strip and grooves side having a peripheral edge region, which preferably protrudes from the strip and on which rests an edge region of the insulating film, wherein between the edge region and the strip is a recessed gap gap whose depth corresponds to the depth of the grooves.

By this arrangement, a secure support surface for the frame-like insulating film is achieved, whereby the sufficient distance between the strips of a graphite electrode and the strip of the second graphite electrode lying thereon is ensured.

The strips of the graphite electrodes, which protrude from the base of the graphite electrode, are located opposite the peripheral edge region, so that in any case it is ensured that there is no contact between the opposing strips of graphite electrodes in the assembly target layer, but a sufficient gap between the strips, which are aligned with each other, consists. In addition, it can be provided that the insulating film projects beyond the edge region to the outside and optionally also to the inside.

This embodiment ensures that a voltage flashover on the adjacent edges of the graphite electrode is excluded, since this is prevented by the projecting portions of the insulating film.

Furthermore, it is preferably provided that the housing surrounding the composite structural unit is formed by a plastic compound, with which the structural unit is encapsulated or encapsulated.

The entire unit formed from the individual elements is suitably encapsulated or encapsulated with plastic compound, so that a fully encapsulated arrangement of the components is achieved. Only the connecting parts used for connecting connecting elements protrude from this plastic compound so that the corresponding connection can be mounted.

Preferably, it is provided that the plastic compound is a hotmelt material which can be sprayed with low pressure.

In particular, it is preferably provided that the plastic mass consists of a polyamide.

Just such a hotmelt material, in particular a polyamide, wraps around the individual components of the component and connects itself excellently with the Outside surface of the electrode material, so that a permanently sealed and insensitive device is provided.

Fig. 1

Eine komplette Trennfunkenstrecke in Draufsicht gesehen;

Fig. 2

desgleichen im Schnitt II II der Figur1 gesehen;

Fig. 3

desgleichen im Schnitt III III der Figur 1 gesehen;

Fig. 4

eine Einzelheit in Ansicht;

Fig. 5 und 6

weitere Einzelheiten ebenfalls in Ansicht.

An embodiment of a separating spark gap according to the invention is shown in the drawing and described in more detail below. It shows:

Fig. 1

A complete spark gap seen in plan view;

Fig. 2

likewise in section II II of the Figur1 seen;

Fig. 3

likewise in section III III of FIG. 1 seen;

Fig. 4

a detail in view;

FIGS. 5 and 6

further details also in view.

In FIG. 1 a corresponding spark gap is shown, which is installed to equipotential bonding between components that carry different electrical potential.

This separating spark gap has a first electrode 1 with a first connection part 2, a second electrode 3 with a second connection part 4 and a spark gap arranged between the electrodes 1, 3, wherein the assembly composed of these components is surrounded by an insulating material housing 5, from which only The connection line 2, 4 protrude so that they are accessible for installation and connection of corresponding connection parts.

As in particular in FIG. 4 As can be seen, each electrode 1, 3 has a flat-rectangular contact region 6, which is recessed in relation to a peripheral edge region 7. At this contact region 6 connects via an angled portion 8 of the contact region 2, 4.

In FIG. 4 only one of the formed as a flat molded part electrodes 1, 3 is shown. The second electrode has the same design and is placed in 180 ° turned and rotated by 180 ° shape on the other electrode, so that the mounting target position is set, as in FIG. 2 can be seen in section.

In the desired position, the two electrodes 1, 3 are insulated from one another with their contact region 6 stacked on each other. Between the electrodes 1, 3, two substantially flat rectangular graphite electrodes 9, 10 are arranged, which are separated from each other by a frame-like insulating film 11 and spaced. The two graphite electrodes 9, 10 are again formed identical. A view of such a graphite electrode 9, 10 is in FIG. 6 shown. The insulating film 11 is in FIG. 5 shown as a detail.

The mutually facing surface regions of the graphite electrodes 9, 10 have mutually parallel protruding strips 12 and intervening grooves 13 on. The long transverse edges of the strips 12 of these surface areas 9, 10 are each aligned at least slightly offset from each other in the assembly target position, so that in the assembly target position, as shown in the FIG. 2 is shown, in each case a peripheral edge of a transverse edge of a first graphite electrode 9 of a groove 13 of the second graphite electrode 10 is opposite. This is realized in a simple manner in that the strips 12 and grooves 13 are not arranged symmetrically or centrally on the surface of the electrode 9 and 10, respectively, but offset somewhat, which becomes clear in that FIG. 6 at the right edge of the graphite electrode the distance between the strip 12 to the edge of the graphite electrode 9 is less than at the left edge. This makes it possible that during assembly identical graphite electrodes 9, 10 are used, the lower graphite electrode 9 in the orientation according to FIG. 6 is positioned and the applied graphite electrode 10 is turned over by 180 ° and placed rotated so that in the overlying electrode 10, the narrow area between the strip 12 and the edge is on the left, while the wide area between the strip 12 and the edge is right. As a result, a corresponding offset of the strips 12 is achieved to each other, which is particularly advantageous for the effect of the spark gap, in particular their response, their response and their isolation behavior.

The electrodes 1, 3 are preferably castings made of zamak, wherein their contact surfaces (9 Area 6) are nickel-plated to ensure a good contact.

As in particular in FIG. 2 As can be seen, the electrodes 1, 3 are connected to one another by connecting screws 14. The shaft of the connecting screws 14 passes through the electrodes 1, 3 and the graphite electrodes 9,10 at corresponding holes. The head of the connecting screw 14 and its shank in the penetration region through the one electrode 1 or 3 and the graphite electrodes 9, 10 is electrically insulated from the electrodes 1 and 3 and the graphite electrodes 9, 10 by a flanged insulating sleeve 15. The shank end of the fastening screw 14 is screwed into the opposite electrode 3 or 1. It is thus achieved a well isolated but secure connection of the elements.

The insulating sleeve 15 is preferably made of POM material.

The graphite electrodes 9, 10 have a coding contour 16, in particular a corner flattening or bevel, at a corner region of their flat-rectangular form. This embodiment is to help the Montierenden to ensure the correct position arrangement of the graphite electrodes 9, 10 to each other.

The frame-like insulating film 11 has at its two opposite transverse edge edges each have a projection 17. The electrodes 1, 3 have a region adjacent to the edge of the film matching recess 18, in which the projection 17 is inserted in assembly target position. This is also a mounting aid for the Montierenden and additional a position assurance for the insulating film 11 in the Vormontagelage.

The insulating film 11 is preferably made of aramid paper.

In the exemplary embodiment, the graphite electrodes 9, 10 have a number of 11 strips 12, each of which is adjacent to a corresponding groove 13. In addition, the graphite electrodes 9, 10 have on their strip 12 and the grooves 13 side having a peripheral edge region 9, which preferably protrudes low relative to the level of the strip 12. An edge region of the insulating film 11 rests on this circumferential edge region 19 in the assembly target position. Between the edge region 19 and the ends of the strips 12, a recessed gap gap is provided, the depth of which corresponds to the depth of the groove 13, so that the edge regions 12 rise island-like from the base surface of the graphite electrode.

In assembly target position, the insulating film 11 preferably projects beyond the edge region 19 to the outside and slightly inward. How out Figure 1 to 3 it can be seen that the housing 5 surrounding the assembled structural unit is formed by a plastics material with which the structural unit is molded or cast around. All cavities within the assembly, so the edge regions of the electrodes 1, 3 and the edge regions of the graphite electrodes 9,10 are surrounded by plastic mass. As plastic compound, a low-pressure-sprayable hotmelt material is preferably used. The plastic compound may preferably consist of a polyamide.

Claims (15)

1. A spark gap arrester as a potential equalization device comprising a first electrode (1) with a first connection portion (2), a second electrode (3) with a second connection portion (4), a spark gap arranged between the electrodes (1, 3) and a housing of insulation material (5) enclosing the assembly composed of these components, connection pieces (2, 4) protruding from said housing or being accessible, each electrode having (1, 3) a flat rectangular contact region (6) and a connection portion (2, 4) protruding on one side therefrom, characterized by that both electrodes (1,3) are layered with their contact regions on each other and are insulated from each other, and between the electrodes (1, 3) two substantially flat rectangular graphite electrodes (9, 10) are disposed that are spaced from each other by a frame-type insulating film (11), and that the surface areas facing each other of the graphite electrodes (9, 10) comprise parallel protruding stripes (12) and grooves (13) between the stripes (12), the long cross borders of the stripes (12) of the surface areas of the graphite electrodes (9, 10) being at least slightly displaced relative to each other, so that one border edge each of a cross border of a stripe (12) of a first graphite electrode (9, 10) fronts a groove (13) of the second graphite electrode (9, 10).
2. The spark gap arrester according to claim 1, characterized by that both electrodes (1, 3) have an identical shape and are layered in opposite sense turned by 180º on each other, the connection pieces (2, 4) protruding opposite to each other at the ends of the thus formed component.
3. The spark gap arrester according to claim 1 or 2, characterized by that the electrodes (1, 3) are molded zamac parts, contact surfaces (6) of which abutting the graphite electrodes (9, 10) are nickel-plated.
4. The spark gap arrester according to one of claims 1 to 3, characterized by that the electrodes (1, 3) are connected by connecting screws (14), the shaft of which penetrates the graphite electrodes (9, 10), the head of the connecting screw (14) and the shaft thereof being electrically insulated from the electrode (1, 3) and the graphite electrodes (9, 10) in the penetration region through an electrode (1, 3) and through the graphite electrodes (9, 10) by a sleeve of insulating material (15) provided with a flange, and the shaft end being screwed into the opposite electrode (3, 1).
5. The spark gap arrester according to claim 4, characterized by that the sleeve of insulating material (15) consists of POM.
6. The spark gap arrester according to one of claims 1 to 5, characterized by that the graphite electrodes (9, 10) comprise, at a corner section of their flat rectangular shape, a coding contour (16).
7. The spark gap arrester according to one of claims 1 to 6, characterized by that the frame-type insulating film (11) comprises, at at least one cross border edge, a projection (17), and the electrodes (1, 3) comprise, in the area adjacent to the border edge, a matching recess (18), in which, in the desired mounting position, the projection (17) is fitted.
8. The spark gap arrester according to one of claims 1 to 7, characterized by that the insulating film (11) consists of aramide paper.
9. The spark gap arrester according to one of claims 1 to 8, characterized by that the graphite electrodes (9, 10) comprise a number of more than five stripes (12) and less than fifteen stripes (12).
10. The spark gap arrester according to one of claims 1 to 9, characterized by that the graphite electrodes (9, 10) comprise, on their side comprising the stripes (12) and grooves (13), a circumferential border section (19) that protrudes relative to the stripes (12) and on which a border section of the insulating film (11) rests, between the border section (19) and the stripes (12) a recessed distance gap being provided, the depth of which corresponds to the depth of the grooves (13).
11. The spark gap arrester according to claim 10, characterized by that the insulating film (11) projects beyond the border section (19) outwardly or also inwardly.
12. The spark gap arrester according to one of claims 1 to 11, characterized by that the housing (5) enclosing the composed assembly is formed by a plastic mass, which is sprayed or molded around the assembly.
13. The spark gap arrester according to claim 12, characterized by that the plastic mass is a hotmelt material being moldable at low pressure.
14. The spark gap arrester according to one of claims 12 or 13, characterized by that the plastic mass consists of a polyamide.
15. The spark gap arrester according to claim 6, characterized by that the coding contour (16) is a flat corner section or a chamfer.

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