JPS6015103B2 - Lightning arrester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lightning arrester used in a current arrester for protecting a communication device or a human body from external surges flowing into a communication line.

Conventionally, this type of device uses an earth arrester as shown in Fig. 1A.

1 and 2 are communication lines, 3 and 4 are fuses, and 5 and 5'
, 6 are detonators, and these fuses 3, 4 and detonators 5
, 6 constitute a lightning arrester.

The arrester tubes 5 and 6 shown in Fig. 1A are bipolar detonators each having a pair of discharge electrodes enclosed in a single container, with one electrode connected to the communication line and the other electrode connected to the ground potential. Connecting. The detonator 5' shown at the front of the figure is a three-pole snow arrester, which has the functions of the two bipolar detonators 5 and 6, and the details will be described later. and 7 is a communication device protected from surges. With this configuration, if communication lines 1 and 2
If the arrester is destroyed when induced lightning or other surges flow in, the surge will directly enter the communication equipment and destroy the equipment. Therefore, when this type of earth protection device is directly destroyed, a short circuit occurs between the electrodes, the fuses 3 and 4 are blown by the power supply current, and the device is disconnected from the communication line. Therefore, it is an essential condition for a detonator used in such a configuration that a short circuit occurs when the detonator is destroyed. Conventionally, in order to provide this kind of function, this type of snow escape tube has either had its electrodes welded together by the heat caused by over-discharge current, or had a structure in which the arrester support case detects breakage of the arrester and removes both electrodes. It had the ability to short-circuit connected conductors. However, such a structure has drawbacks both from the point of view of reliability of operation and from the point of view of economy. In addition, as shown in Fig. 2A, three electrodes 8, 9, and 10' are arranged opposite each other at the apex positions of a substantially equilateral triangle, and each electrode is A structure in which a plurality of grooves 11 are provided on the outer surface of the electrode, and the heat generated in the electrodes causes the electrodes to curve on the opposite side of the grooves, that is, so that the three electrodes come close to each other, and to bring the electrodes into contact with each other and short-circuit them. When the electrodes are in a vertical position, they operate normally, but when the electrodes are placed in a horizontal position as shown in Figure 2, the bottom electrode 8 bends downward, so the three Electrodes 8, 9, 10 cannot be brought into contact with each other. Therefore, there was a drawback that the structure of the arrester main body or support body had to be changed depending on the installation direction of the arrester (such as whether it was placed at the end or on the side). In order to solve these drawbacks, the present invention provides the detonator itself with a function of short-circuiting between the electrodes using the heat of overdischarge current.The present invention will be described in detail with reference to the drawings below.

FIG. 3A is a cross-sectional view of an embodiment of the bipolar detonator of the present invention, in which 12 and 13 are lead wires connected to the communication line and the ground potential, 14 and 14' are electrodes that form the discharge gap 18;
Reference numerals 15 and 15' denote ceramic external elements made of ceramic cylinders, and the electrodes 14 and 14' are soldered and bonded to both end surfaces of the external elements, respectively.

The opening of the same figure is a perspective view of a single ceramic envelope used in the embodiment of the present invention described above. A portion of the chamber 21 having an inner diameter is provided. The third mentioned above
As shown in Figure A, two opposing electrodes 14, 14
' are provided with convex portions on the inside of each other.

Further, the discharge gap 18 is filled with an inert gas. The low melting point alloy 17 is attached in advance to the inner wall surface of the outer envelope so as not to come into contact with the electrodes attached to both end surfaces of the outer envelope, and then attached to one of the electrodes attached to the outer envelope. The metal body 16, 16' from one of the electrodes is fixed by screwing. Note that the metal body 16
, 16' are provided with bar-shaped protrusions, and the tips of the protrusions are arranged in advance so as to be close to the electrodes 14, 14' facing each other. Next, these operations will be explained.

A two-pole arrester is usually connected between the communication line and the ground.
When lightning or other external surges enter a communication line, a discharge occurs between the electrodes within the detonator, causing the external surge to escape to the ground. However, if a cross-contact accident occurs due to high-voltage electric wires, etc., the arrester will continue to discharge for a long time, resulting in the temperature of the arrester rising, causing holes in the metal electrode, melting of the sealing part, and the inside of the arrester. The inert gas escapes, and as a result, the firing voltage increases, and high pressure is applied to the device, destroying it. However, if the arrester tube of the present invention is used in a vertical position as shown in FIG. The alloy 17 melts and flows into the short circuit cavity 19 in the ceramic envelope, and as shown in FIG. 4, the melted alloy 17 shorts the electrode 14 provided on the end face of the ceramic envelope and the metal body 16 Therefore, the electrodes 14 and 14' are electrically conductive, and the fuses 3 and 4 shown in FIG. 1 are reliably cut, thereby preventing high voltage from being applied to the communication device.

Further, in the structure of the present invention, as shown in the embodiments, the above-mentioned function is achieved no matter what direction the arrester is placed.

For example, even if the lead wires 12 and 13 are oriented vertically as shown in Fig. 4, the low melting point alloy 17 is vertically symmetrically inserted into both ceramic external generators 15 and 15', so that the discharge continues for a long time. Even if the temperature of the detonator rises abnormally, one of the electrodes becomes conductive and the desired purpose is achieved. Furthermore, even when the lead wires 12 and 13 are turned horizontally by nine rotations as shown in FIG. Since the portion of the chamber 21 having an inner diameter larger than the inner diameter is also held in advance, when the low melting point alloy 17 becomes molten, the molten alloy 17 short-circuits the electrode 14 and the metal body 16, causing an electrical failure. Becomes compliant.

Furthermore, the present invention is not limited to the two-pole detonator as shown in FIG. 3A, FIG. 4, and FIG. It can also be applied to multi-pole lacquered detonators.

FIG. 6 shows a three-pole discharge tube 5' shown in the opening of FIG. 1 according to the present invention.
FIG.

20 is an intermediate electrode connected to the ground potential, and communication line 1
, 2 via lead wires 12 and 13.
, 14', and is formed of a metal plate with a circular hole in the center facing the center of the discharge gap 18 formed between them, and the front and back surfaces are hermetically sealed with the ceramic envelope 15.

Therefore, a discharge gap is formed between each electrode 14, 14' and the intermediate electrode 20, and when an abnormal voltage enters either of the communication lines 1, 2, both electrodes 14,
14' occurs, suppressing abnormal voltage between the communication line and the ground and between the communication lines, and protecting the communication device from surges. FIG. 7 is a sectional view showing an embodiment of the present invention in a multi-pole arrester, 20', 20'', 20'''...
. . . are intermediate electrodes, each of which has a structure substantially similar to the intermediate electrode 20 shown in FIG. 6, is connected to each communication line, and has a function of absorbing abnormal voltage between the lines.

As explained above, the present invention has a function in the extrinsic device of the detonator to short-circuit between the electrodes due to the temperature rise of the detonator itself, and this function is achieved regardless of the installation direction of the detonator, so it is possible to It is useful for protecting various communication devices connected to lightning damage.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an earth arrester for communication lines, where A shows a case where a two-pole earth arrester tube is used, and the figure A shows a case where a three-pole earth arrester tube is used. Figure 2A shows a conventional self-short-circuiting mechanism for a discharge tube; Figure 3 shows an embodiment in which the present invention is applied to a two-pole discharge tube; Figure A is a sectional view; It is a perspective view of an enclosure. Figure 4 is a cross-sectional view after a long period of discharge with a pair of electrodes placed on the top and bottom, and Figure 5 is a long-term discharge with a pair of electrodes placed on the left and right. 6 is a cross-sectional view of an embodiment in which the present invention is applied to a three-pole detonator, and FIG. 7 is a cross-sectional view of an embodiment in which the present invention is applied to a multi-polar detonator. Figures are shown respectively. 1, 2...
... Communication line, 3, 4 ... Fuse, 5, 6.
...2-pole arrester, 5'...3-pole arrester, 7...
... Communication device, 8, 9, 10 ... Electrode, 11
...... Groove on the outer surface of the electrode, 12, 13... Lead wire, 14, 14'... Discharge electrode, 15, 15'...
...Ceramic external organ, 16,16'...Metal body, 17...Low melting point alloy, 18...
Discharge gap, 19...Short circuit cavity, 20,2
0', 20'', 20'''...Intermediate electrode, 21
・・・・・・Room. Figure O Z diagram is J diagram Guy diagram O S diagram O 5 diagram O 7 diagram

Claims (1)

[Claims] 1 Electrodes electrically connected to lead wires are arranged at both ends of a plurality of ceramic envelopes each having a cavity having a step on the inner wall surface, respectively, and are arranged facing each other via a discharge gap. A metal body having a bar-shaped protrusion is inserted into one end of the enclosure so as to pass through one electrode and be close to the other opposing electrode, and the metal body having the bar-shaped protrusion is inserted into the ceramic body. The electrode at the other end of the ceramic envelope is connected to the other end of the ceramic envelope, which is opposite to one end of the envelope, through the other electrode opposite to the electrode provided with the metal body having the rod-shaped protrusion. A metal body having a bar-shaped protrusion is inserted into the ceramic envelope so as to be close to the ceramic envelope, and a metal body having a bar-shaped protrusion is inserted between the stepped inner wall surface of the ceramic envelope and the bar-shaped protrusion of the metal body. A low melting point metal layer is formed so that the metal body is in electrical contact with the electrode provided thereon, and the tip of the metal body does not come into contact with the adjacent electrode. A detonation arrester characterized in that the low melting point alloy is melted by heat generation, and the alloy short-circuits between electrodes disposed opposite to each other at both ends of the ceramic envelope, regardless of the installation direction of the ceramic envelope.