EP3490085A1 - Spark gap assembly and method for securing a spark gap assembly - Google Patents

Abstract

Spark gap arrangement with a discharge chamber (6), an electrode head (4) and a contact connection (9) arranged outside the discharge chamber (6), the electrode head (4) being electrically conductively connected to the contact connection (9) and mechanically coupled such that at Removal of the contact terminal (9) from its position or when the contact terminal (9) reaches a predetermined position, the electrically conductive connection is interrupted and the electrode head (4) is mechanically decoupled from the contact terminal (9), so that the electrode head (4) in the direction of Discharge chamber interior and / or within the discharge chamber (6) is movable.

Description

The invention relates to a spark gap arrangement which is protected against manipulation.

Spark gap arrangements are used in many ways. One embodiment is a triggerable spark gap, which is also referred to as a trigger spark gap. A trigger spark gap usually has at least two main electrodes and a trigger electrode. For example, the electrodes are arranged in a gas-filled space. By applying a corresponding trigger voltage to the trigger electrode, a spark gap between the trigger electrode and one of the main electrodes is ignited. For example, an ionized path is created in the gas-filled space through which a current flows between the trigger electrode and the one main electrode. By the ignition by means of the trigger electrode is then achieved that forms another conductive channel between the two main electrodes, which allows a current flow between the main electrodes.

Such triggerable spark gaps can be used for example as a surge arrester. Another application is, for example, in the targeted switching of high voltage.

In conventional triggerable spark gaps, the switching between the main electrodes becomes instantaneous triggered by applying the trigger pulse to the trigger electrode.

A typical delay time, also referred to by the English term "delay time", for a gas-filled trigger spark gap may be in the range of less than 1 μs. The delay time depends on the magnitude of the generator voltage at the main electrodes in relation to their self-breakdown voltage, SBV for short. The lower the generator voltage, the longer the delay time. It is also dependent on the level of the trigger voltage. The lower the trigger voltage, the greater the delay time. By tuning the above variables, the delay time can be adjusted to some extent.

In some applications, a large delay time is desired. A typical value is a delay time greater than 15 μs. It should be noted that gas-filled trigger spark gaps with a current of greater than 500 A and a delay time of less than or equal to 15 μs may be subject to restrictions as regards their use and export.

Although the delay time can be influenced as outlined above, it is not possible to achieve an ignition delay for a gas-filled trigger spark gap, which statistically reliably exceeds a high limit value, such as 15 μs. Rather, the values of the delay time are very high and there is still a fraction in a batch with a delay time of less than 15 μs.

To meet these requirements, therefore, an ignition delay circuit may be provided in the trigger spark gap, which causes the predetermined time delay between the trigger pulse and the breakdown is maintained. Thus, the condition can be satisfied that the delay time is above the typical limit of 15 μs.

Given the desired unconditional compliance with the desired minimum delay time, such a spark gap should be protected against manipulation of the delay time. In particular, to prevent the ignition delay circuit to be disabled.

This problem is solved by a spark gap arrangement having the features of patent claim 1, namely a spark gap having a discharge chamber, an electrode head and a contact terminal arranged outside the discharge chamber, wherein the electrode head is electrically conductively connected to the contact terminal and is mechanically coupled in such a way that, upon removal of the spark plug Contact terminal from its position or upon reaching the contact terminal a predetermined position, the electrically conductive connection is interrupted and the electrode head is mechanically decoupled from the contact terminal, so that the electrode head is movable in the direction of the discharge chamber and / or within the discharge chamber.

The discharge chamber is a gas-filled, for example, air-filled, space in which the discharge or spark gap formation between electrodes can take place. He can be completed. The discharge chamber may be delimited by insulator and / or electrode walls.

The electrode head is an electrically conductive part, at which a transition of the current supplied through the terminal contact can be made in the gaseous medium in the discharge chamber. For example, the electrode head may include the trigger electrode in a trigger gap. It can terminate with an insulating wall of the discharge chamber or at least partially or completely protrude into the charge chamber interior.

The control and supply of the electrode head takes place via the contact connection. For example, an ignition delay circuit is connected to the contact terminal. Such a compound is usually difficult or impossible to solve. Thus, even attempting to remove or manipulate the ignition delay circuit results in movement of the contact terminal from its original position. This causes the electrode head to both be electrically decoupled, which prevents the application of a voltage and in particular a trigger pulse, as well as mechanically decoupled, so that the electrode head is movable from its position and can fall into the discharge chamber interior due to gravity or by spring force. An electrode head already positioned inside is no longer held in position and is movable in the discharge chamber. In both cases, the electrode head, for example, by vibration, to move away from its position relative to the main electrodes, which affects the function of the spark gap assembly.

An detached electrode head located in the charge chamber interior can no longer be coupled to the contact connection, so that the functionality of the spark gap arrangement is permanently disturbed. Thus, not only an ignition delay below the predetermined value, but the operation of the entire spark gap arrangement is suppressed.

In the normal operating state of the spark gap arrangement, which is a trigger spark gap, its function is ensured by the fact that the electrode head of the trigger electrode maintains its normal position relative to the main electrode and the electrical connection to the contact terminal and thus the Zündverzögerungsschaltung exists.

An embodiment of the spark gap assembly includes a coupling mechanism having a first coupling part that includes the contact terminal and a second coupling part that includes the electrode head. The first coupling part is movable relative to the second coupling part. When the contact connection is removed from its position or when the contact connection reaches a predetermined position, the electrode head is permanently mechanically decoupled from the contact connection.

The permanent mechanical decoupling does not necessarily have to take place even with the slightest movement of the contact connection, as can occur, for example, during rough operation, but can also take place as soon as the contact connection has reached a predetermined position. The predetermined position is the minimum change in position of the contact terminal, in which the first coupling part and the second Coupling have such a distance from each other that the mechanical decoupling is permanent, or irreversible.

It should be noted that the separation of the electrical connection and the permanent separation of the mechanical connection need not necessarily coincide. Already at low deflection of the contact terminal can interrupt the electrical connection, but the mechanical decoupling is not permanent. The permanent decoupling can be done after the electrical, as soon as the contact terminal has reached a predetermined position.

The decoupled electrode head, which is movable in the direction of the discharge chamber space or within the discharge chamber, can leave its original position after decoupling and move within the discharge chamber driven by gravity and movement changes of the spark gap arrangement. This is one way to achieve permanent decoupling. Movements during operation or gravity may be sufficient for the decoupled electrode head to slip out of its positional support.

In one embodiment, the electrode head is coupled to the contact terminal via a magnetic connection. The first or the second coupling part may comprise this magnet. Advantageously, the magnet is provided in the first coupling part and holds the electrode head in position by the magnetic material properties. As soon as the first coupling part is moved relative to the second coupling part when the contact connection is removed from its position or into a predetermined position, the magnet is also moved away from the electrode head. In this In this case, the magnetic force of attraction to the electrode head is no longer sufficient to hold it in place.

If the spark gap arrangement is exposed to high temperatures, the magnetization decreases to such an extent that the electrode head can no longer be held fast. Even at high accelerations of the spark gap arrangement, the magnetic connection can solve.

In one embodiment, the spark gap arrangement comprises an ejection mechanism which is triggered when the contact terminal is removed from its position or when the contact terminal of a predetermined position is reached. This ejection mechanism is suitable for moving the electrode head in the direction of the discharge chamber interior and / or within the discharge chamber.

This ejection mechanism allows the movement of the electrode head from its original position also against gravity or regardless of its position to gravity. A movement with gravity, ie in a vertical position, is assisted by the ejection mechanism, which enables the safe and permanent decoupling of the electrode head by pushing the electrode head into the discharge chamber interior. The previously flawless function of the spark gap arrangement is interrupted and can not be restored by manipulation in the back room of the switch. The spark gap arrangement becomes unusable.

By means of this spark gap arrangement is due to both mechanical and magnetic properties a Force exerted on the electrode head, by means of which the electrode head is moved from its original position. This overrides the function of the spark gap arrangement if an attempt is made to manipulate the contact pad, for example by removing the delay time electronics from the trigger gap.

In one embodiment, the ejection mechanism includes a spring member that is retained by a catch in a preloaded condition. Upon release of the ejection mechanism, the lock releases the spring element and the spring force acting on the electrode head pushes it out of position. A spring element is a component which yields under load and, after discharge from the prestressed state, returns to the original shape, that is to say it behaves elastically restoring. Advantageously, tension or compression springs are used, which experience a change in length under load. Examples of this are helical compression coil springs or leaf springs.

Advantageously, the first or the second coupling part comprises a guide bush in which the spring element is positioned. Such a guide bushing keeps the spring element in the pretensioned state in its position and, after unlocking, allows the targeted guidance of the restoring spring in the direction of the electrode head. A guide bush, for example, pot-shaped or sleeve-shaped. Advantageously, the spring element is a helical compression spring whose length is reduced in the prestressed state. It can be positioned adjacent to the inner walls of the guide bush and also offers in the center Space for other components of the coupling mechanism, such as the magnet.

The lock can be moved from a position blocking the return of the spring element to a position in which it releases the return of the spring element. In other words, the barrier is positioned to obstruct the return of the expanding spring. In this case, the first and the second coupling part are coupled in such a way that the movement of the barrier is initially blocked and, on removal of the contact connection from its position or upon reaching the contact connection in a predetermined position, is made possible.

Furthermore, a movable ejector may be provided, which is arranged between the spring element and the electrode head. The lock engages in this ejector, so that its movement is blocked and the spring element is held in its biased state. Upon relaxation of the spring element after releasing the lock, the spring element moves back to its original shape and thereby moves the ejector in the direction of the electrode head, so that it is pushed out of its original position and pushes the electrode head into the discharge chamber interior.

A barrier as described above may comprise a ball or a pin, that is a cylindrical element. These are positioned in a recess of the guide bushing. A retaining means blocks the movement of the ball or the pin in the position in which the provision of the spring element is released, so at Removal of the contact terminal from its position or on reaching the contact terminal of a predetermined position, the ball or the pin away from the retaining means in the position in which the provision of the spring element is released, are moved. Such a retaining means may be a wall, a pot or a sleeve, which prevent the ball or the pin during normal operation of the movement with which the spring element is released. Only when removing the contact terminal from its position or when reaching the contact terminal of a predetermined position leave the balls or pins together with the guide bush their original position. As soon as they are moved away from the retaining means, which they push into their position, the spring force pushes them aside so that the spring element can relax.

The corresponding method for securing a spark gap arrangement, as described above, against manipulation comprises removing the contact connection from its position, interrupting the electrically conductive connection, mechanically decoupling the electrode head from the contact connection and the electrode head in the direction of the discharge chamber interior and / or inside the discharge chamber is moved.

Advantageous embodiments are objects of subclaims.

The invention will be explained below with reference to the drawing with reference to an embodiment.

The single FIGURE shows a cross-sectional detail of an essential part of an embodiment of a spark gap arrangement.

The spark gap arrangement, in this case a trigger spark gap, comprises a discharge chamber 6, which is shown in sections, with two main electrodes (not shown), which may be arranged, for example, in the discharge chamber 6 at the end. Further, a trigger head 3 serving as an electrode is provided between the main electrodes, which is driven via a contact terminal 9 by an ignition delay circuit (not shown). The contact terminal 9 and the Zündverzögerungsschaltung are advantageously at least difficult to detachably connected to each other. The contact terminal 9 may also be an integral part of the Zündverzögerungsschaltung.

The section of the spark gap arrangement shows the coupling mechanism with a first coupling part 1 and a second coupling part 2. The second coupling part 2 comprises the trigger head 3 with an electrode head 4 and a magnetic connecting piece 5 which is connected to the electrode head 4. The materials of the electrode head 4 and connector 5 may differ, allowing material optimization with respect to their respective function. Alternatively, the trigger head 3 may be integrally formed of metal, which may be held by a magnet or is itself a magnetic metal (not shown).

The electrode head 4 is in a recess in the electrically insulating wall 20 of the discharge chamber 6 positioned so that its bottom is flush. This recess serves as a frame for the electrode head receptacle and position holder. Alternative embodiments comprise an electrode head 4 projecting into the discharge chamber 6, an electrode head 4 positioned inside the discharge chamber or recessed with respect to the wall 20 (not shown).

Below this electrode head 4 is the main discharge gap 7, along which the discharge can proceed.

The first coupling part 1 comprises a contact terminal 9, which merges into a cylindrical connecting piece 10. Alternatively, the terminal 9 and the connector 10 may be made in two parts. Within the connecting piece 10, a recess is provided, in which a, in this embodiment, cylindrical, magnet 11 is located. There is a magnetic connection 12 between the magnet 11 and the trigger head 3, so that both the magnet 11 and the connecting piece 10, or only one of these components, touch the trigger head 3. Via the connecting piece 10, which, like the terminal contact 9, comprises conductive material, there is an electrically conductive connection between the electrode head 4 and the terminal contact 9. Alternatively, the connecting piece 10 and the magnet 11 can also be made in one piece. Other shapes are conceivable.

The first coupling part 1 also has a cup-shaped guide bushing 8, protruding from the bottom of the terminal contact 9. The side walls of the guide bush 8 are spaced around the connector 10. The Guide bushing 8 and the connecting part 10 and the contact terminal 9 are connected to each other. Alternatively, the connector 10, with or without terminal 9, and the guide bushing 8 as a piece, that is, in one piece, be made.

Between the connecting piece 10 and the inner walls of the guide bush 8, a spring element 13, in this case a helical compression spring is provided. Below the spring element 13, a sleeve-shaped ejector 14 is provided, which is positioned around the connecting piece 10 continuously between the spring element 13 and the trigger head 3. The ejector sleeve 14 has at its the spring element 13 facing edge a flange 15. The spring element 13 is clamped between the bottom of the guide bushing 8 and the flange 13, so that it is in a prestressed state.

The region of the guide bush 8 facing the trigger head 3 is positioned in a pot 18 running around the outside through whose bottom the lower region of the connecting piece 10 extends to the trigger head 3. The side walls of the guide bush 8 extend completely or partially into the pot 18 inside. Alternatively, a sleeve or wall is conceivable. The pot 18 is connected to the recess 20 for the electrode head 4 forming walls, so that both the guide bushing 8 and the decoupled electrode head 4 are movable to the pot 18.

In the trigger head 3 facing region of the guide bush 8, which is positioned in the pot 18, recesses 17 are provided. By the recesses 17 locks can be performed below the flange 15 to the ejector 14. In this embodiment are as locks balls 16 provided. For example, two opposing balls 16 may be provided which are in the recesses between the inner wall of the pot and the outer side of the ejection sleeve. More than two balls are also possible. Already one ball can be enough. The size of the balls 16 is chosen so that they protrude over the inner wall of the guide bush 8 when lying against the inner wall of the pot and prevent it from moving in the direction of the electrode head 4 below the flange 15. As a result, both the ejector sleeve 14 and the prestressed spring element 13 are held in position.

The spring element 13 is enclosed in the guide bush 8 and impeded by the ball lock in its power development, as long as the balls 16 are held by the pot 18 in position.

The first coupling part 1 can be held in its position in the spark gap system during normal operation by holding means 19, for example hooks, springs or snap connections, which for example attach to the guide bush 8. These holding means 19 permit a movement of the guide bush 8, which leads to the decoupling of the electrode head 4, even at slight manipulations at the contact connection 9, for example the attempted removal of the delay circuit attached thereto (not shown).

A coupling mechanism, such as described above, allows in the normal operating mode of the spark gap arrangement their proper functioning in that the electrode head 4 maintains its position relative to the main electrode and also the electrically conductive connection to the contact terminal 9 is maintained. this will achieved in that the electrode head 4 is coupled via the magnetic connection 12 to the contact terminal 9. About this contact terminal 9 can be done from a back room serving as a switch spark gap arrangement on the delay time circuit, the supply of trigger voltage and current.

If the guide bush 8 as well as the connecting piece 10, for example in a manipulation attempt, moved away from the electrode head 4, the magnetic connection 12 is first interrupted to the electrode head 4, since both the guide bush 8 and the contact terminal 9 and the connecting element 10 with the inside Magnets 11 are moved away from the electrode head 4. Upon further withdrawal of the guide bushing 8 from the pot 18, the balls 16, the flange 15, acts on the spring force, escape to the outside and release the spring-loaded ejector sleeve 14. The ejector sleeve 14 will push the electrode head 4 of the trigger electrode, also against gravity, into the main discharge gap 7 or into the discharge chamber interior. This causes a permanent mechanical decoupling and prevents the function of the spark gap arrangement.

The interruption of the electrical and mechanical contact with the electrode head 4 takes place in the event that the contact terminal 9 and thus the supply to the delay circuit manipulated or the delay circuit is to be removed. The magnetic attraction force to the electrode head 4 is no longer sufficient to hold this. In addition, in addition, the spring force acts, so that the electrode head 4 in the Discharge chamber 6 is moved. The function of the spark gap arrangement is thereby permanently prevented.

It should be understood that the features of the described embodiments and embodiments may be combined.

LIST OF REFERENCE NUMBERS

1

first coupling part

2

second coupling part

3

trigger head

4

electrode head

5

holding area

6

discharge chamber

7

Main discharge gap

8th

guide bush

9

Contact Termination

10

connecting part

11

magnet

12

magnetic connection

13

spring element

14

ejector

15

flange

16

Bullet

17

recess

18

pot

19

retaining element

20

wall

Claims (12)

Spark gap arrangement comprising a discharge chamber (6), an electrode head (4) and a contact terminal (9) arranged outside the discharge chamber (6), wherein the electrode head (4) is electrically conductively connected to the contact terminal (9) and mechanically coupled such that Removal of the contact terminal (9) from its position or upon reaching the contact terminal (9) in a predetermined position, the electrically conductive connection is interrupted and the electrode head (4) from the contact terminal (9) is mechanically decoupled, so that the electrode head (4) in the direction the discharge chamber interior and / or within the discharge chamber (6) is movable,
and wherein the electrode head (4) is coupled to the contact terminal (9) via a magnetic connection (12). Spark gap arrangement according to claim 1
comprising a coupling mechanism having a first coupling part (1) comprising the contact terminal (9) and a second coupling part (2) comprising the electrode head (4), the first coupling part (1) being movable relative to the second coupling part (2) is and upon removal of the contact terminal (9) from its position or when reaching the contact terminal (9) in a predetermined position of the electrode head (4) is permanently decoupled from the contact terminal (9) mechanically. Spark gap arrangement according to claim 1 or 2,
wherein the first and / or the second coupling part (1, 2) comprises a magnet (11). Spark gap arrangement according to one of claims 1 to 3,
comprising an ejector mechanism (8, 13, 14, 16) triggered upon removal of the contact terminal (9) from its position or upon reaching the contact terminal of a predetermined position and adapted to direct the electrode head (4) towards the discharge chamber interior and / or or to move within the discharge chamber (6). Spark gap arrangement according to claim 4,
wherein the ejection mechanism (8, 13, 14, 16) comprises a spring element (13) which is held by a lock in a prestressed state. Spark gap arrangement according to claim 4,
wherein the first or the second coupling part (1, 2) comprises a guide bush (8) in which the spring element (13) is positioned. Spark gap arrangement according to claim 5 or 6,
wherein the spring element (13) is a helical compression spring. Spark gap arrangement according to one of claims 5 to 7,
wherein the lock is movable from a position in which it blocks the return of the spring element (13) to a position in which it resets the Spring element (13) releases, and wherein the first and the second coupling part (1, 2) are coupled in such a way that the movement of the lock is blocked and upon removal of the contact terminal (9) from its position or upon reaching the contact terminal (9) in a predetermined position the unlocking is enabled. A spark gap assembly according to any one of claims 5 to 8, comprising a movable ejector (14) disposed between the spring member (13) and the electrode head (4), the lock engaging the ejector (14) so that its movement is blocked. Spark gap arrangement according to one of claims 6 to 9,
the lock comprising a ball (16) or pin positioned in a recess (17) of the guide bush (8). Spark gap arrangement according to claim 10,
comprising retaining means (18) which blocks the movement of the ball (16) or pin to the position in which the return of the spring element (13) is released so that upon removal of the contact terminal (9) from its position or upon reaching of the contact terminal (9) of a predetermined position, the ball (16) and the pin away from the retaining means (18) in the position in which the provision of the spring element (13) is released, are moved. Method for securing a spark gap arrangement with an electrode head (4), a discharge chamber (6) and a manipulation contact terminal (9) disposed outside the discharge chamber (6), the electrode head (4) being electrically conductively connected and mechanically coupled to the contact terminal (9), and wherein the method comprises, when the contact terminal (9) of is removed from its position, the electrically conductive connection is interrupted, the electrode head (4) from the contact terminal (9) is mechanically decoupled and the electrode head (4) in the direction of the discharge chamber and / or within the discharge chamber (6) is moved.

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