JPS6062070A - Grounding device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a grounding device for grounding an electrical system.

[Prior Art and Its Problems] It is important to ground almost all electrical systems, for example, in homes or in offices, factories, power plants, and other buildings. Ground pins or other grounding devices have been widely used for this purpose.

This grounding device is buried or driven into the ground near or directly under the building, and the electrical system is connected to this grounding device.

This grounding device is prone to corrosion due to exposure to ground moisture or other electrolytes. For this reason, copper is generally used, since iron and aluminum, although substantially cheaper than copper, are rapidly corroded by moist soil.

[Object of the invention] This invention was made in view of the above problems, and
It is an object of the present invention to provide a grounding device that uses a conductive polymer member and has corrosion resistance without deteriorating electrical performance.

[Summary of the Invention] The inventor of this invention has developed a grounding device by using a core polymer to prevent contact between the metal parts of the device and the soil in which the device is buried. It has been found that corrosion of metals can be prevented or significantly retarded without adverse effects on the electrical performance of metals.

This discovery made it possible to use steel, aluminum, or other relatively inexpensive metals in place of copper.

The grounding device of the present invention takes the form of a grounding pin driven into the ground.

However, particularly in power generation and substations, etc., it is preferable to use the apparatus of the present invention in conjunction with open mesh mats that are buried under buildings.

[Structure of the Invention] In the electrical system using a grounding device buried underground, the grounding device includes (a) a first member made of metal and at least partially buried underground; and (aXi) an organic material. (ii) powder-like conductive charge 1 dispersed within this polymer;
(b) is in electrical contact with the first member and the earth; (C) is surrounding the first member and has all electrical connections between the earth and the first member; 4''.

[Embodiment] The first member of the earthing device is made of metal such as iron or aluminum.

In the case of a grounding pin, the first member has an upper working surface on which force is applied to facilitate driving the earthing device into the ground, and for this purpose this first member has sufficient strength. .

If used for the ground pin, inexpensive and strong steel is preferably used, and the first member is a steel bar with a diameter of 0.2 to 1 inch (0.5 cm to 2.5 cm). Values of 0.25 inch to 0.5 inch (0.6 cm to 1.25 cm) are preferred.

The second member is made of an electrically conductive polymer and is electrically connected to the first member.
It surrounds the member and is in electrical contact with the first dark member. This is to prevent the first member from being exposed to any corrosive action in the soil in which the earthing device is buried. Typically, the second member is at least 0.2 inch (0.25 cm), preferably 0.2 inch to 0.2 inch (0.25 cm) in diameter.
The coating was applied around the first member to a thickness of 5 inches (0.5 cm to 1.25 cm+).

Contact of the first member with soil is prevented by engineering or adding to the second member more other members, such as insulating polymeric materials or members that corrode more slowly than the first part. You can also do that. The electrically conductive filler used in the electrically conductive polymer is preferably corrosion resistant and for this reason substantially carbon or graphite or both, such as carbon black, carbon fibres, graphite flakes or graphite fibres. Consists of carbon-based materials.

Acetylene black is a preferred conductive filler. Particularly when the filler is fibrous, it also acts as a reinforcement for the filler.

The conductive polymer may contain additives conventionally used for polymer construction, such as antioxidants, flame retardants, and non-conductive fillers.

The amount of conductive filler should be such as to ensure that the ground pin performs the grounding function.

The resistivity of a conductive polymer at 25°C is 1OΩ・cm
or 10-2Ω・cm, especially 5Ω・cm or 0, IΩ
- It is preferable that it is cm.

If the amount of filler is insufficient, the electrical resistance of the second member will be too high, but if the amount of filler is too large, the second member will have too high an electrical resistance.
The resistance of the part to physical impact forces becomes too low and molding of the second part becomes difficult.

Preferably, the electrically conductive polymer increases its resistivity when heated by passing a ground current through the polymer.

This is because when a ground current passes through it, it tends to equalize the current density across the surface of the grounding device. No large increase in resistivity is necessary; 25°C to 75°C
Preferably, the resistivity increases by a factor of at least twice that.

The conductive polymer used may be one type of polymer or a mixture of multiple types of polymers. A factor that needs to be taken into account when selecting a polymer is, for example, the physical impact force that acts on the second part (A) when the grounding pin is driven into the soil. Measures are taken to reduce or eliminate the frictional forces on the second member when the pin is driven into the ground.However, if such measures are not taken, the polymer, such as a polyethylene polymer, It should be of sufficient strength to allow the ground pin to be driven into the soil without significant damage to the second member.

As mentioned above, when the ground pin is driven into the ground, the second
Measures are taken to reduce or eliminate frictional forces on the members.

In one such embodiment, the ground pin has a pointed portion at its lower end, which portion is (i) comprised of an insulating material, such as a hard polymer, or (ii
) It is made of a conductive material and is separated and insulated from the first member by a second member or an insulating part.

The diameter of the lower end of the pin is such that when the ground pin is driven into the ground, the pin makes a large enough hole in the ground to prevent significant frictional forces from acting on the second member. I can make it bigger.

As another specific example, this lower end side portion is part of the third part. (a) the third member is constructed of metal; and (b) the third member is configured to prevent significant frictional forces from acting on the second part when the pin is driven into the ground. Constructed to surround.

After a grounding pin with an outer metal member is inserted into the ground, the outer member, which has the function of protecting the second member when the pin is inserted into the ground, has an adverse effect on its electrical effectiveness as a grounding pin. Corrodes rapidly without causing damage.

Referring to the drawings, FIGS. 1 and 2 show vertical cross-sectional views of the grounding pin of the present invention, and the grounding pin has a first part I made of metal having a pressure-resistant surface 11 at the upper end, and a second part I. Part 1 shrine
and a second part shrine 2 made of a conductive polymer surrounding the shrine.

In FIG. 1, the first member l has a pointed and enlarged lower end portion 12 constructed of a rigid insulating polymer, and this lower end portion I2 is connected to a ground pin or Protects conductive polymers when embedded in.

In FIG. 2, the ground pin connects a second member 2 made of a conductive polymer to a third part made of metal surrounding the second member 2. FIG. 2 shows a clamp 4 for tying the ground wire to the first part shrine.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG. 2 is a sectional view showing another embodiment. 1...First part shrine, 2...Second part shrine. Patent applicant Raychem Corporation Agent
Patent attorney Blue and White Blue and two others Drawings Jiro (No change in 1) Procedural amendment (rounded corners) September 27, 1981 Display Patent Application No. 1723.30 of 1982 2, Title of Invention Grounding Device 3, Relationship to the Amended Person's Case Patent Applicant Address 300 Conception Drive, Menlo Park, California 94025 California Name v Ykem, Corporation 4 agent

Claims (1)

[Claims] (+) In an electrical system using a grounding device buried underground, the grounding device is: (a) a first member made of metal and at least a portion of which is buried underground; (aXi) an organic polymer; (ii) a granular conductive filler dispersed within the polymer; (b) is in electrical contact with the first part (A and the earth); (c) is surrounding the first part of fiij and is in contact with the earth and the first part
An electrical system comprising: a second member that makes full electrical connection with the unit. (2) The electrical system according to claim 1, wherein the grounding device is a grounding pin driven into the ground by applying force to the working surface of the second part of the first member. (3) The electrical system according to claim 2, wherein the ground pin has a pointed lower end made of an insulating material. (4) The grounding pin has a pointed lower end made of a conductive material, and the lower end is insulated and separated from the first member by the second member or the insulating part side. An electrical system according to scope 2. (5) The electrical system according to claim 1, wherein the grounding device is an open-mesh mat. (6) The resistivity of the second member is 10Ω・cm at 25℃
6. An electrical system as claimed in any one of claims 1 to 5, comprising a conductive material having a resistivity of from io-'Ω·cm to io-'Ω·cm. (7) Electrical according to any one of claims 1 to 6, in which the resistivity of the electrically conductive composition increases by a factor of at least t) 2 between 25° C. and 75° C. system. (8) The electrical system according to any one of claims 1 to 7, wherein the conductive filler is substantially made of a carbon-based material. (9) (a) What is the part that is made of rod-shaped hard metal and has a part on the top that connects to the electrical system that requires grounding?
The lower part is composed of a first member to be buried underground, and (b) an electrically conductive material including (a) a polymer and a carbon-based, particularly electrically conductive filler dispersed in the polymer; ) a second member surrounding and in electrical contact with the lower portion of the first member, and when driven into the earth, makes all electrical connections between the earth and the first member; A grounding pin characterized by comprising: (10) The second member is at least 0.1 inch (0°2
5 cm) and a resistivity of 10 Ω·cm to 10 −′ Ω·cm at 25° C.
Ground pin as described in section.