JP2002373802A - Lighting conductor pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lightning conductor pipe having a lower discharge start voltage for a surge voltage. SOLUTION: A space surrounded by an insulating box 1 and an insulating substrate 2 is filled with argon gas and sealed. A conductive layer 3 having a desired specific resistance is formed on the substrate 2 by transferring a structural element or a dispersing element having a predetermined composition by the use of friction or abrasion, or coating. Electrodes 4 and 5 are formed on both ends of the conductive layer 3. The resultant assembly is connected to a communication device with lead wires 6 and 7. The conductive layer 3 contains carbon as a conductive material and a metal or semimetal compound as a material impairing conductivity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-filled lightning arrester for protecting electronic circuits, electronic components, and communication devices from surges such as lightning surges.

[0002]

2. Description of the Related Art In general, when a lightning surge is induced in a communication cable, for example, a lightning arrester is used to protect electronic circuits, electronic components, and communication devices connected to the cable from the lightning surge. The surge voltage generated in the circuit discharges the surge arrester and releases the surge to the ground, protecting the circuit, parts and equipment. Therefore, it is important that the lightning arrester operates at as low a voltage as possible without impairing the operation of the equipment.

[0003]

In a conventional lightning arrester, an elongated conductive portion is provided on the inner wall surface of an airtight insulating container, and when an abnormal voltage such as a surge occurs, an electric field is applied to the tip of the conductive portion. A method has been adopted in which the discharge starting voltage with respect to the surge voltage is reduced by concentrating and promoting ionization of the gas molecules sealed in the lightning arrester at that portion. This method is extremely effective. However, in recent years, a large number of semiconductor elements have been used in communication devices, and the communication devices have become extremely weak against abnormal voltages such as surges. At present, it is not enough. That is, an object of the present invention is to solve the above-mentioned problems and to provide a lightning arrester having a lower discharge starting voltage with respect to a surge voltage.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that an insulating container and a thin film provided on a part of the inner wall of the insulating container and containing a conductive material and a conductive inhibition material are provided. It has been confirmed that the above-mentioned problem can be effectively solved by a lightning arrester having a pair of electrodes provided at both ends of the thin film. The conductive material is carbon, and the conductivity inhibiting material is a metal or metalloid compound. The carbon includes carbon powder and carbon obtained by firing an organic substance together with the carbon powder and the metal or metalloid compound. The conductive material is also selected from the group consisting of graphite, copper, aluminum, titanium, iron, chromium, manganese, cobalt, nickel, molybdenum, gold, platinum, silver, lead, zinc, and tungsten; Talc, mica, boron nitride, fluorinated graphite, carbon fluoride, alumina, at least one kind of constitutional material selected from the group consisting of silica, thermoplastic organic polymer, thermosetting organic polymer, and wax And at least one binder selected from the group consisting of: The above-mentioned thin film can be formed by transfer in which structures having the same composition are rubbed and worn. The above-mentioned thin film can also be formed by transferring a dispersion having the same composition such as coating.

The above-mentioned metal or metalloid compounds include generally available metal carbides, metal borides, metal silicides, metal nitrides, metal oxides, metalloid carbides, metalloid borides, metalloid silicides. , Semimetal nitride, semimetal oxide and the like. The type and amount of the metal compound and the metalloid compound to be used are appropriately selected depending on the intended discharge starting voltage, and may be used alone or in a mixture of two or more.
In particular, boron carbide, silicon carbide, boron nitride, alumina, and silica are preferably used because of the simplicity of resistance value control. The amount of carbon is preferably 7 to maintain the excellent properties of carbon.
It is preferably 0 parts by mass or less.

As the above-mentioned organic substance, an organic substance exhibiting a carbonization yield of 5% or more by firing in an inert gas atmosphere is used. Specifically, thermoplastic resins such as polyvinyl chloride, polyacrylonitrile, polyvinyl alcohol, polyvinyl chloride-polyvinyl acetate copolymer, polyamide, and polyimide; phenol resins, furan resins, epoxy resins, and unsaturated polyester resins. Curable resins, lignin, cellulose, tragacanth gum, gum arabic, natural high molecular substances having condensed polycyclic aromatics such as saccharides in the basic structure of the molecule, and formalin condensates of naphthalenesulfonic acid, which are not contained above, copna Synthetic polymer substances having a condensed polycyclic aromatic compound such as a resin in the basic structure of the molecule are exemplified. The type and amount of the organic substance used are appropriately selected depending on the shape of the intended heating element, and can be used alone or in a mixture of two or more kinds.
It is preferable to use a furan resin, and in order to maintain the excellent properties of carbon, the amount used is preferably 30 parts by mass or more.

Examples of the above-mentioned carbon powder include carbon black, graphite, and coke powder. The type and amount of the carbon powder used are appropriately selected according to the intended discharge starting voltage with respect to the surge voltage. However, a mixture of two or more kinds can be used, but it is particularly preferable to use graphite because of simplicity of shape control.

The above-mentioned constitutional materials include talc, mica,
At least one kind of plate-like particles such as boron nitride, graphite fluoride, carbon fluoride, and alumina is selected, and the average particle diameter in the plane direction is adjusted to 20 μm or less, preferably 10 μm or less. The thickness direction of the plate-like particles is 1 μm or less, preferably 0.1 μm.
It may be adjusted to 5 μm or less, more preferably 0.3 μm or less.

It is desirable that all of the body material be the above-mentioned plate-like particles, but if necessary, other body materials such as fibrous substances can be used in combination. Even in that case, it is preferable to add the plate-like particles at a ratio of at least 20% by mass or more in the whole material from the viewpoint of the degree of improvement in mechanical strength in forming the structure.

[0010]

FIG. 1 shows the structure of an arrester according to an embodiment of the present invention. In FIG. 1, an argon gas is sealed and sealed in a space surrounded by an insulating container 1 and an insulating substrate 2, and a structure or a dispersion having a predetermined composition is rubbed, abraded or coated on the substrate 2. In the case where an abnormal voltage such as a surge is generated, the conductive layer 3 is formed by the transfer in
The surge voltage is discharged by concentrating the electric field between the conductive part and the electrode to promote ionization of the gas molecules sealed in the lightning arrester in that part.

In the conductive layer 3, carbon and carbon powder derived from an organic substance act as a good electrical conductor, and a metal compound or a metalloid compound acts as a conduction inhibitor. It jumps over a metal compound and flows using so-called carbon and carbon powder as a medium while hopping. Therefore, by changing the types and ratios of these three components and uniformly mixing and dispersing them, a desired specific resistance value and
It is assumed that a surge arrester having a discharge starting voltage can be obtained.

Alternatively, in the conductive layer 3, graphite, copper, aluminum, titanium, iron, chromium, manganese, cobalt,
Fine metal powders including alloys of nickel, molybdenum, gold, platinum, silver, lead, zinc, tungsten, etc. are used as good electrical conductors, and talc, mica, boron nitride, graphite fluoride, carbon fluoride, alumina, and other inorganic fillers The thermoplastic organic polymer material, thermosetting organic polymer material, and waxes used as the bonding material and the structural material such as the material are acting as the conductivity inhibitor, and the surge current jumps over the conductivity inhibitor, so-called hopping. It flows through the metal fine powder component. It is presumed that a surge arrester having a desired specific resistance value and discharge starting voltage can be obtained by changing the types and ratios of these components and uniformly mixing and dispersing them.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0014]

(Example 1) 39 parts by mass of a chlorinated vinyl chloride resin (T-741 manufactured by Nippon Carbide) as an organic substance, and natural graphite fine powder (average particle size of 5 μm manufactured by Nippon Graphite) 6
With respect to 0 parts by mass, 1 part by mass of silica powder and 20 parts by mass of diallyl phthalate monomer as a plasticizer are added, dispersed, mixed, extruded, and then fired in a nitrogen gas atmosphere to obtain a columnar carbon-based material. A structure was obtained.

The obtained carbon-based structure has a sectional diameter of 1.2.
mm, and the bending strength was 200 MPa. When the specific resistance was measured by the Wheatstone bridge method, it was 7.2 × 1
It had a value of 0 ^-4 Ωcm. This structure was abraded and transferred onto an insulating alumina substrate 2 (FIG. 1).
A conductive layer 3 having a size of 2 mm and a length of 3 mm was formed, and nickel-plated copper was provided as electrodes 4 and 5 on both side ends of the conductive layer 3. The glass tube was filled with argon gas and sealed and sealed.

While the discharge starting voltage with respect to the surge voltage of the conventional lightning arrester was about 400 V, the discharge starting voltage of this embodiment was measured to be about 200 V.

(Example 2) 10 parts by mass of celluloid, 60 parts by mass of copper powder, 15 parts by mass of caster wax, 15 parts of talc
To 30 parts by mass of ethyl acetate as a solvent, the mixture was mixed and dispersed, and then extruded, and then treated at a relatively low temperature of about 100 ° C. to remove the solvent. I got

The obtained structure had a cross-sectional diameter of 0.6 mm and a bending strength of 100 MPa. When the specific resistance was measured by the Wheatstone bridge method, it was 4.7 × 10 ⁻⁵ Ω.
had a value of cm. This structure was abraded and transferred onto an insulating alumina substrate 2 and was 0.6 mm thick and 3 mm long.
The conductive layer 3 was formed, and nickel-plated copper was provided as electrodes 4 and 5 on both side ends of the conductive layer 3, and the glass tube was filled with argon gas and sealed and sealed.

While the discharge starting voltage with respect to the surge voltage of the conventional lightning arrester was about 400 V, when the discharge starting voltage of this embodiment was measured, it was reduced to about 150 V.

(Example 3) Dispersion resin methyl methacrylate 10 parts by mass, copper powder 60 parts by mass, caster wax 1
5 parts by mass and further 60 parts by mass of ethyl acetate as a solvent were added and mixed and dispersed to obtain a paste-like ink composition.

This ink composition was applied onto an insulating alumina substrate 2 and transferred to form a conductive layer 3 having a width of 0.6 mm and a length of 3 mm, and nickel plating was applied to both ends of the conductive layer 3. Copper was provided as electrodes 4 and 5, and the glass tube was filled and sealed with argon gas.

When the discharge starting voltage with respect to the surge voltage of the conventional arrester was about 400 V, the discharge starting voltage of the present embodiment was measured to be about 170 V.

[0023]

As described above, the lightning arrester of the present invention can obtain the desired specific resistance value and discharge starting voltage by changing the kind of the composition and the ratio thereof, and uniformly mixing and dispersing them. In addition, there is an effect that the discharge starting voltage with respect to the surge voltage can be reduced. ADVANTAGE OF THE INVENTION According to this invention, the protection ability of a communication apparatus etc. with respect to the abnormal voltage of a arrester can be improved further.

[Brief description of the drawings]

FIG. 1 is a view showing a structure of a lightning arrester according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Insulating container 2 ... Insulating substrate 3 ... Thin film conductive layer 4, 5 ... Electrode 6, 7 ... Lead wire

Claims (4)

[Claims] 1. An insulating container, a thin film provided on a part of an inner wall of the insulating container and containing a conductive material and a conductivity inhibiting material, and a pair of electrodes provided at both ends of the thin film. Surge arrester equipped. 2. The lightning arrester according to claim 1, wherein the conductive material is carbon, and the conductivity inhibiting material is a metal or metalloid compound. 3. The lightning arrester according to claim 2, wherein the carbon includes carbon powder and carbon obtained by firing an organic substance together with the carbon powder and the compound of the metal or metalloid. 4. The conductive material is selected from the group consisting of graphite, copper, aluminum, titanium, iron, chromium, manganese, cobalt, nickel, molybdenum, gold, platinum, silver, lead, zinc, and tungsten. The conduction inhibiting material is at least one kind of a constitutional material selected from the group consisting of talc, mica, boron nitride, graphite fluoride, carbon fluoride, alumina, and silica, a thermoplastic organic polymer material, and a thermosetting organic polymer. The arrester according to claim 1, further comprising at least one binder selected from the group consisting of a substance and wax.