JPH03250576A - Accelerating method for insulation recovery of molybdene lightning arrester - Google Patents

Abstract

PURPOSE:To enhance the subsequent current shutoff performance by utilizing the fact that dielectric breakdown of a Mo oxidated covering due to discharging recovers at the same time as ending of the discharge, putting sand-shaped material fully around electrodes, encapsulating oxygen in the voids, and allowing an impact wave current to flow momentarily for obtainment of recovery. CONSTITUTION:Mo electrodes 5, 6 of a Mo lightning arrester are in mutual contact, and insulation is attained by insulative oxidation films on the surfaces of the electrodes 5, 6. Oxygen is encapsulated in an electrode vessel 12 to accelerate the oxidizing speed of the film, and at the same time, a sand-shaped material 13 such as Zr sand or quartz sand is put fully to prevent sputtering of high temp. film at discharging. In the event of lightning discharge to the conductor to be protected 2, the lightning current discharges to the electrodes 5, 6 to run off to the ground 7. At this time, the lightning current destroys the insulation of the surface oxidation films on the electrodes 5, 6 to generate a temporary continuing state, but after ending of the discharge the electrode surfaces are forcedly oxidized by oxygen in the vessel 12 to provide recovery of insulation.

Description

[Detailed Description of the Invention] The present invention relates to a lightning arrester that has the characteristics that it is difficult for radio signals to pass through, but large shock wave currents such as those caused by direct lightning strikes can instantly pass through to restore insulation, and that it is difficult to break. Regarding improvements to improve.

This invention is filed in Patent Application No. 49072 dated February 27, 1990.
The title of the invention is to prevent a phenomenon in which the dielectric strength of the oxide film on the surface of molybdenum decreases in order to further improve the lightning protection performance when putting a molybdenum lightning arrester into practical use.

The present invention will be specifically explained with reference to the drawings.

As shown in Figure 1, in a molybdenum lightning arrester, picture electrodes 5 and 6 made of molybdenum are in contact with each other, and the insulation between them is maintained by the electrically insulating oxide films on their respective surfaces. ing.

However, in the original invention, the means for forming an oxide film after discharge was dependent on the atmosphere, so in order to further increase the oxidation rate, it was necessary to increase the amount of oxygen.

For this purpose, the present invention seals oxygen into the electrode container 12,
Sand-like material 1 that accelerates the oxidation rate of the coating and has high insulation properties and excellent thermal conductivity such as zircon sand or silica sand
This is an improved method that satisfies condition 3 and prevents the scattering of the high-temperature oxide film during discharge.

When the conductor 2 to be protected is struck by lightning, lightning current is discharged from the electrode 5 to the electrode 6 and escapes to the ground 7.

At this time, the lightning current breaks the insulation of the surface oxide films of the electrodes 5 and 6, and the electrodes become electrically conductive for a moment.

After the lightning current has passed, the oxide film on the surface of the molybdenum, which has undergone dielectric breakdown due to the lightning discharge, is forcibly oxidized by the oxygen sealed in the container 12, returning it to the original insulator.

Therefore, any subsequent current that is energized by a radio wave signal or commercial voltage or the like that is about to flow is immediately interrupted.

Effects of the Invention Conventionally, a general discharge gap uses an inert gas such as nitrogen to prevent oxidation of the metal surface.

The present invention, on the contrary, differs in that the electrode surface is forcibly oxidized with oxygen.

In addition, sandy materials such as zircon sand and silica sand are used in power fuses, but the mission of the sandy material in this case is to replace the fuse, which is a conductor, with an insulating material, when the fuse melts and disappears. That's the point.

The presence of the sand-like material in the present invention is primarily intended to protect the high-temperature oxide film from scattering during discharge, and is also expected to have a cooling effect on the electrodes.

From the above viewpoint, the present invention greatly contributes to the practical application of the original invention.

[Brief explanation of drawings]

Figure 1 shows the features of the present invention! It is a buried map. For convenience, the numbers indicating the symbols in this figure are the same as those of the original invention. 1. Antenna 2 is the conductor 5 connected from antenna 1 to the communication device.
Conducts electricity using a molybdenum electrode with an oxide film on the outer surface!
Connected to 2. 6 is connected to the ground 7 by a molybdenum electrode having the same structure as the molybdenum electrode 5. 7 is the grounding 12, and is the container for the heather lightning arrester, which also shows the entire structure. 13. is a sand-like material such as zircon sand or silica sand.

Claims (1)

[Claims] In molybdenum lightning arresters that take advantage of the property that dielectric breakdown of the molybdenum oxide film due to discharge recovers at the same time as the discharge ends, highly insulating and thermally conductive materials such as zircon sand or silica sand are used to prevent the high-temperature oxide film from scattering during discharge. A high-quality sand-like material is filled around the electrode, and in order to accelerate the oxidation rate of the molybdenum electrode, oxygen is sealed in the gap between the sand-like materials, and the oxygen causes defects in the oxide film on the surface of the molybdenum. A method for promoting insulation recovery of a molybdenum lightning arrester by forcibly restoring its parts.