WO1998056073A2

WO1998056073A2 - Ground rod and installation method for the same

Info

Publication number: WO1998056073A2
Application number: PCT/KR1998/000138
Authority: WO
Inventors: Nam Ung Baek
Original assignee: Dong Yang Industrial Co., Ltd.
Priority date: 1997-06-03
Filing date: 1998-06-01
Publication date: 1998-12-10
Also published as: WO1998056073A3; AU7789198A

Abstract

A ground rod having a configuration capable of supplying a chemical resistance reducing agent into the earth surrounding the ground rod, if desired, thereby reducing the contact resistance between the ground rod and the ground while enhancing the grounding performance of the ground rod. The invention also provides an installation method for such a ground rod. The ground rod includes a cylindrical ground rod body (10) provided with a cavity (20), the ground rod body (10) being also provided at an upper end thereof with a through hole communicating with the cavity (20) and at a desired portion thereof with a lead (12), a connecting pipe (14) fitted at a lower end thereof in the through hole of the ground rod body (10), and a supply tube (18) fitted at a lower end thereof in the connecting pipe (14) and provided at an upper end thereof with a housing (26) having a plurality of draft openings formed through a side wall of the housing, the housing also having a lid (24) hingeably mounted to an upper end of the housing (26).

Description

GROUND ROD AND INSTALLATION METHOD FOR THE SAME

Technical Field

The present invention relates to a ground rod and a method for installing such a ground rod, and more particularly to a ground rod having a configuration capable of supplying a chemical resistance reducing agent into the earth surrounding the ground rod, if desired, thereby reducing the contact resistance between the ground rod and the ground while maintaining the grounding performance of the ground rod, and to provide an installation method for such a ground rod.

Background Art

Generally, ground rods are well known which are widely used as a grounding means for electrically connecting electric appliances, lightning conductors or communication appliances to the ground in order to protect the human body and those appliances from a thunderbolt or other abnormal high voltage .

As well known, such ground rods are driven into the surface of the earth. Where the material of a ground rod embedded in the ground is incompatible with the chemical properties of the ground, it is difficult for the ground rod to allow current to flow into the ground without any resistance. In this case, it is impossible to accomplish the purpose of the ground rod to dissipate the thunderbolt or other abnormal high voltage into the ground.

In order to enhance the grounding effect of such a ground rod driven into the surface of the ground, it is most effective to minimize the ground resistance of the ground rod. In this regard, it is important to determine the characteristics of the ground rod used and the properties of the earth surrounding the ground rod where it is driven or to reduce the contact resistance between the ground rod and the earth based on the determined factors. The properties of the earth surrounding the ground rod are fixedly determined when the ground rod is installed whereas the characteristics of the ground rod and the contact resistance between the ground rod and the earth can be optionally adjusted. The most effective method, which is capable of reducing the ground resistance, thereby obtaining an enhanced grounding effect, is to adjust the contact resistance between the ground rod and the earth.

Referring to FIG. 5, a conventional ground rod is illustrated. As shown in FIG. 5, the ground rod, which is denoted by the reference numeral 10b, has a cylindrical structure. The ground rod 10b has a lead 12 which extends from a desired portion of the ground rod 10b. In order to install the ground rod 10b, the earth 16 is first dug to a desired depth, thereby forming a hole. Thereafter, the ground rod 10b is inserted into the hole and then covered with earth while exposing the lead 12. A chemical resistance reducing agent is sprayed onto the earth surrounding the ground rod 10b, in order to reduce the contact resistance between the ground rod 10b and the ground 16, thereby obtaining an effect of reducing the ground resistance. Finally, the lead 12 is connected to a ground line extending from an external installation to be grounded. Since the chemical resistance reducing agent is distributed around the ground rod 10b in this case, it is possible to improve the effect of reducing the ground resistance of the ground rod 10b. This method is advantageous in that it provides a reduced contact resistance between the ground rod and the ground, as compared to the case in which a ground rod comprised of a copper plate or copper wire is used. In this case, however, there is a problem in that the effect of the chemical resistance reducing agent decreases greatly or disappears completely over the lapse of time. Furthermore, where it is desired to further reduce the target contact resistance due to an increase in the load of the external installation to be grounded, it is necessary to re-install the ground rod in order to reduce the ground resistance.

Disclosure of the Invention

The present invention has been made to maintain the performance of the chemical resistance reducing agent used, in view of the above mentioned problems, and, therefore, an object of the invention is to provide a ground rod having a configuration capable of supplying a chemical resistance reducing agent into the earth surrounding the ground rod, if desired, thereby reducing the contact resistance between the ground rod and the ground while enhancing the grounding performance of the ground rod, and to provide an installation method for such a ground rod. Another object of the invention is to provide a ground rod having a configuration capable of supplying a chemical resistance reducing agent into the earth surrounding the ground rod when a reduced target resistance is required due to an increase in the load of external equipment to be grounded after an installation of the ground rod, without any re-installation of the ground rod, and to provide an installation method for such a ground rod.

Another object of the invention is to provide a ground rod having a configuration capable of achieving an easy installation of the ground rod without any damage to the surroundings by simply drilling a hole in the ground using a puncher or drill, and to provide an installation method for such a ground rod.

In accordance with one aspect, the present invention provides a ground rod comprising: a cylindrical ground rod body provided with a cavity, the ground rod body being also provided at an upper end thereof with a through hole communicating with the cavity and at a desired portion thereof with a lead; a connecting pipe fitted at a lower end thereof in the through hole of the ground rod body; and a supply tube fitted at a lower end thereof in the connecting pipe and provided at an upper end thereof with a housing having a plurality of draft openings formed through a side wall of the housing, the housing also having a lid hingably mounted to an upper end of the housing.

In accordance with another aspect, the present invention provides an installation method for a ground rod including a ground rod body having a cavity, a lead coupled to a desired portion of the ground rod body, a connecting pipe extending upwardly from an upper end of the ground rod body and communicating with the cavity, and a supply tube connected to an upper end of the connecting pipe and provided at the upper end thereof with a housing, the supply tube serving to supply a chemical resistance reducing agent into the ground rod body, comprising the steps of: performing a geological test to find an optimum earth layer; drilling a ground rod hole into the ground to a depth where the earth layer is positioned; inserting the ground rod into the drilled ground rod hole; filling a portion of the ground rod hole over the ground rod body with an ultrafast-curable cement material, and curing the cement material; and injecting a chemical resistance reducing agent under high pressure into the supply tube by use of a compressor, thereby feeding the chemical resistance reducing agent to the cavity under pressure.

Brief Description of the Drawings

Other objects and aspects of the invention will become apparent from the following description of embodiments with reference to the accompanying drawings in which:

FIG. 1 is a perspective view illustrating the entire configuration of a ground rod according to the present invention;

FIG. 2 is a sectional view illustrating a state of the ground rod of FIG. 1 driven into the ground;

FIG. 3 is a sectional view illustrating a state in which a chemical resistance reducing agent is injected into the ground rod of FIG. 1;

FIG. 4 illustrates sequential steps of an installation method for the ground rod of FIG. 1; and

FIG. 5 is a sectional view illustrating a conventional ground rod driven into the ground.

Best Mode for Carrying Out the Invention

FIGS. 1 to 3 illustrate a ground rod according to the present invention whereas FIG. 4 illustrate a method for driving the ground rod into the ground in accordance with the present invention. As shown in FIGS. 1 to 4, the ground rod of the present invention includes a ground rod body 10, a connecting pipe 14, and a supply pipe 18 provided at its upper end with a housing 26.

The ground rod body 10 has a hollow cylindrical structure. That is, the ground rod body 10 is provided with a cavity 20. A lead line 12 is connected to a desired portion of the ground rod body 10. The ground rod body 10 is also provided at its upper end with a through hole 10a communicating with the cavity 20.

The connecting pipe 14 is fitted at its lower end in the through hole 10a of the ground rod body 10, so that it communicates with the cavity 20 of the ground rod body

10. A flange 14a is integrally formed at the upper end of the connecting pipe 14.

The supply pipe 18, which is adapted to supply a chemical resistance reducing agent into the ground rod body 10, is fitted at its lower end in the upper end of the connecting pipe 14. The housing 26, which is formed at the upper end of the supply pipe 18, has an appropriate number of draft openings 28. A lid 24 is hingably coupled to the upper end of the housing 26.

The cavity 20, which is defined in the interior of the ground rod body 10, extends vertically and has an open lower end. The lead 12 is embedded at one end thereof in a desired portion of the ground rod body 10 and connected at the other end thereof to a ground line extending from an installation to be grounded.

The connecting pipe 14 serves to easily connect the supply pipe 18 to the ground rod body 10. The connecting pipe 14 may be made of almost any material, in so far as it exhibits a high durability. Preferably, the connecting pipe 14 is made of stainless steel which is a material capable of withstanding environmental problems such as moisture. The supply tube 18 is not covered with earth. In particular, the upper end of the supply tube 18, to which the housing 26 is coupled, is completely exposed to the atmosphere. The draft openings 28 of the housing 26 serve to supply ambient air into the ground rod body 10. The lid 24 of the housing 26 serves to prevent foreign matters from entering the ground rod. The supply pipe 18 may have an optional length in accordance with the depth of a drilled hole into which the ground rod is driven. The hole, into which the ground rod is to be driven, is drilled to an earth layer most suitable for the installation of the ground rod.

Now, a method for installing the ground rod having the above mentioned configuration in accordance with the present invention will be described in conjunction with FIG. 4.

The ground rod installation method of the present invention involves the steps of: performing a geological test to find a moisture-containing earth layer allowing the ground rod to exhibit a superior grounding effect; drilling a ground rod hole into the ground to a depth where the earth layer is positioned; inserting, into the drilled ground rod hole, a ground rod which includes a ground rod body having a cavity, a lead coupled to a desired portion of the ground rod body, a connecting pipe extending upwardly from the upper end of the ground rod body and communicating with the cavity, and a supply tube connected to the upper end of the connecting pipe and provided at the upper end thereof with a housing, the supply tube serving to supply a chemical resistance reducing agent into the ground rod body; filling a portion of the ground rod hole over the ground rod body with an ultrafast-curable cement material, and curing the cement material; and injecting a chemical resistance reducing agent under high pressure into the supply tube by use of a compressor, thereby forcing the chemical resistance reducing agent to penetrate a desired area of the earth surrounding the ground rod body.

In accordance with this method, a geological test is first carried out for the earth where the ground rod 10 is installed.

The geological test may be carried out by vertically drilling the ground, where the ground rod is to be installed, by use of a drill, and then finding a most suitable earth layer having a large moisture content and exhibiting a low resistance, in accordance with an electrode method. Alternatively, the geological test may also be carried out using an electrical probe method involving no drilling work.

As a result of the geological test, the optimum position, where the ground rod 10 is installed, is determined. Thereafter, a drilling work is carried out using a drill, thereby drilling a ground rod hole 30 to a depth where the most suitable earth layer is positioned.

The ground rod is then inserted into the ground rod hole 30 in such a manner that its ground rod body 10 is seated on the bottom of the ground rod hole 30. In this state, the housing 26 provided at the upper end of the supply pipe 18 is externally exposed. The lead

12 coupled to the ground rod body 10 extends outwardly from the ground rod hole 30.

Under this condition, an ultrafast-curable cement material is filled in a portion of the ground rod hole 30 over the ground rod body 10 and then cured. Thus, installation of the ground rod is completed.

After the curing of the ultrafast-curable cement material, the lid 24 of the externally exposed housing 26 is opened to inject a chemical resistance reducing agent 22 into the ground rod. The chemical resistance reducing agent 22 is injected under high pressure into the supply tube 18 by use of a compressor.

The injected chemical resistance reducing agent 22 flows along the supply tube 18 and then fills the cavity 20 of the ground rod body 10. As a result, the chemical resistance reducing agent 22 is absorbed into the earth 16 surrounding the ground rod body 10.

That is, the chemical resistance reducing agent 22 is distributed over a certain area of the earth 16.

Since the ground rod is seated on the bottom of the ground rod hole 30 in such a fashion that its cavity 20 faces the bottom of the ground rod hole 30 at its open lower end, the chemical resistance reducing agent 22 downwardly supplied into the cavity 20 can be easily absorbed into the surrounding earth.

The housing 26 may be completely exposed to the atmosphere. Alternatively, a manhole member 34 is installed on the ground surrounding the housing 26, in order to cover the housing 26. It is preferred to install such a manhole member in order to eliminate inconvenience in the passage of persons. The chemical resistance reducing agent 22 absorbed in the earth 16 surrounding the ground rod serves to provide a compatibility between the ground rod 10 and the earth 16, thereby reducing the ground resistance of the ground rod. In particular, the density of the earth 16 is reduced because of the injection of the chemical resistance under pressure. Also, the earth 16 surrounding the ground rod uniformly contains moisture because ambient air is supplied into the interior of the ground rod after the injection of the chemical resistance reducing agent 22. Accordingly, the ground resistance can be minimized. Thus, it is possible to obtain a greatly improved grounding effect. Where it is desired to further reduce the target contact resistance due to an increase in the load of the external installation to be grounded, after the installation of the ground rod, this reduction can be achieved by simply additionally supplying the chemical resistance reducing agent 22 into the earth surrounding the ground rod through the supply pipe, thereby reducing the contact resistance between the ground rod and the earth. In this case, accordingly, it is also possible to obtain a superior grounding effect. As mentioned above, ambient air is continuously supplied into the interior of the ground rod 10 through the draft openings 28 provided at the housing 26 mounted to the upper end of the supply tube 18. Since there is a difference in temperature between the supplied ambient air and the internal air in the ground rod, dew forms on the inner surface of the supply tube. This dew enters the cavity 20 along the supply tube 18, so that it flows into the earth surrounding the ground rod body 10. Accordingly, the earth surrounding the earth is maintained in a moist state. This results in an improvement in the performance of the ground rod. Thus, a reduction in the ground resistance is achieved.

Industrial Applicability

As apparent from the above description, the present invention provides a ground rod having a configuration capable of easily repeatedly supplying a chemical resistance reducing agent into the earth surrounding the ground rod. Accordingly, it is possible to greatly reduce the contact resistance between the ground rod and the ground, thereby enhancing the grounding performance of the ground rod. The earth surrounding the earth is also maintained in a moist state by virtue of a difference in temperature between the internal air in the ground rod and ambient air introduced into the interior of the ground rod through draft openings provided at a supply pipe of the ground rod. Accordingly, the ground resistance of the ground rod can be maintained at a desired level.

Although the preferred embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the Invention as disclosed in the accompanying claims.

Claims

1. A ground rod comprising: a cylindrical ground rod body provided with a cavity, the ground rod body being also provided at an upper end thereof with a through hole communicating with the cavity and at a desired portion thereof with a lead; a connecting pipe fitted at a lower end thereof in the through hole of the ground rod body; and a supply tube fitted at a lower end thereof in the connecting pipe and provided at an upper end thereof with a housing having a plurality of draft openings formed through a side wall of the housing, the housing also having a lid hingably mounted to an upper end of the housing.

2. An installation method for a ground rod including a ground rod body having a cavity, a lead coupled to a desired portion of the ground rod body, a connecting pipe extending upwardly from an upper end of the ground rod body and communicating with the cavity, and a supply tube connected to an upper end of the connecting pipe and provided at the upper end thereof with a housing, the supply tube serving to supply a chemical resistance reducing agent into the ground rod body, comprising the steps of: performing a geological test to find an optimum earth layer; drilling a ground rod hole into the ground to a depth where the earth layer is positioned; inserting the ground rod into the drilled ground rod hole; filling a portion of the ground rod hole over the ground rod body with an ultrafast-curable cement material. and curing the cement material; and injecting a chemical resistance reducing agent under high pressure into the supply tube by use of a compressor, thereby feeding the chemical resistance reducing agent to the cavity under pressure.

3. The installation method according to Claim 2, wherein the step of inserting the ground rod into the drilled ground rod hole is carried out in such a manner that the housing is surrounded by a manhole formed in the surface of the ground so as to allow ambient air to enter the interior of the ground rod through the draft openings.