Electricity: conductors and insulators – Earth grounds – Driving type
Reexamination Certificate
2001-07-26
2003-02-04
Dinkins, Anthony (Department: 2831)
Electricity: conductors and insulators
Earth grounds
Driving type
C174S0050SG, C174S006000, C174S002000, C174S003000
Reexamination Certificate
active
06515220
ABSTRACT:
FIELD OF INVENTION
The present invention relates to an improvement to an earth interface. A moisture collecting mesh screen collects moisture from the morning air which is laden with moisture. A conduit feeds this collected moisture to a grounding electrode. At least two collars may be fitted around the known chemically charged hollow grounding electrode installed in a hole. The moisture reduces the surge impedance of the grounding electrode with respect to earth.
BACKGROUND OF THE INVENTION
“Grounding” is the art of making an electrical connection to the earth. That ground connection is actually the interface with earth and through that interface, the grounded system is in electrical contact with the whole earth. Through that interface pass electrical “events” to and from the related system(s). These electrical “events” include power from the utility, communications, phone, radio, and other forms of data.
The character of this interface will determine the effectiveness of its function, i.e., how “good” is the interface and/or is there a reliable, year-round connection to earth. The effectiveness of an interface is usually assessed in terms of its true DC resistance to Mother Earth. However, there is another factor of greater concern to many, that is, the transient response or surge impedance, or the effective inductance of that interface. This factor will determine the effectiveness of that interface for such functions as lightning grounds, RF grounds, electric utility protection equipment grounds and personnel safety under “ground faulting” conditions.
The earth interface system is an important subsystem. The blind application of standards with little reference to the site character or the impact of seasonal changes will seldom yield an effective ground interface.
When the earth interface system has not been properly engineered, significant system equipment damage persists, personnel safety has been impaired and system performance has been less than ideal.
Finally, the trend toward microelectronics has made electrical and electronic systems even more sensitive to any form of anomalous electrical transients. Grounding, the earth interface, must now be considered a vital function and must be engineered for each site and/or system individually.
Grounding systems perform at least one of the following functions:
1. A Ground, or Earth Reference Electrode. Every electrical or electronic system must be referenced to the earth. This is referred to as “grounding”. The grounding point in that system provides a common reference point for circuits within the system. In many cases, the resistance to earth of that reference point is of little significance. For these systems a Common Point Ground (CPG) will satisfy the functional requirements. These systems are usually totally self-contained or autonomously operated systems requiring no external interfaces except possibly the power, and present no potential for a compromise of personal safety. This form of grounding system, the CPG, mandates a separate connection from each element in the system to that CPG preferably via a separate path. A simple example of this CPG is a single computer terminal where the green wire in the power plug is the reference point.
2. The Lightning Neutralization Ground. Lightning protection grounding system requirements have conventionally been thought to be similar to the preceding, when in truth, they are quite different. A more descriptive title would be: “Lightning Charge Neutralization System”. This comes about because of the nature of atmospheric electricity and the lightning strike mechanism. Storm clouds induce an image charge of equal but opposite potential in the earth beneath the cloud. When a lightning channel terminates on an earthen object, that channel forms a conductive path between the two bodies to permit equalization of the charge between them. Since the charge is induced on the surface of the earth, it follows that all of that charge must move from where it was induced to the strike channel terminus in order to neutralize the charge between earth and that cloud. All this must happen in 20 microseconds or so. If the facility of concern is part of the charged body or is the terminus of the strike, its grounding system must provide the low resistance, low surge impedance path from any point in the system to any other point in the system where the strike may terminate. Therefore, the grounding requirement for lightning protection is not just a low (DC) resistance to ground per se, but an interconnecting ground network that electrically interconnects every vulnerable component of the plant or system of concern with a low surge impedance path.
3. A Universal System. The universal grounding system may require a near perfect interface with the earth. That is, the lower the effective resistance between that system ground point and true earth, the better, safer, or more effective the system will be. This requirement is usually associated with systems that have many interfaces with other systems, or the “outside world”. Typical examples include the electrical utility industry, the telephone central office and large industrial plants. These same systems often require a common point grounding (CPG), a lightning neutralization capability, and a low impedance interface with earth; thus providing a universal grounding (or earth) interface.
Soil augmentation is the process of replacing a portion of the local soil with a more conductive soil, or the replacement of poor (high resistance) soil in the critical areas. The new soil must be introduced around the grounding electrode since that is where it will be most beneficial. For years, a form of clay known as Bentonite has been used for this purpose. Its resistivity is found to be about 2.5 ohm-meters which is reasonably conductive. The usefulness of Bentonite is limited by two unfavorable characteristics:
a. Its volume sensitivity to moisture causes it to shrink away from the rod during long dry seasons, its volume can vary by 300%, thus, dramatically increasing the electrode resistance to earth.
b. Its low porosity limits its ability to conduct moisture and dissolved mineral salts into or through it.
To overcome these negative qualities, the present invention may optionally incorporate a product known as “Grounding Augmentation Fill” (GAF™). GAF™ has a resistivity of about 0.5 ohm-meters, it is highly conductive of both moisture and minerals and is far less susceptible to shrinkage.
The use of a good backfill such as GAF™ can significantly reduce the initial resistivity and the ultimate impedance to earth of a grounding electrode when properly utilized. The best use is for replacing the soil in the immediate area (six to twelve inches) surrounding the grounding electrode.
The present invention adds a moisture collector to a grounding electrode, thereby reducing the resistance between the grounding electrode and the surrounding soil.
SUMMARY OF THE INVENTION
Thus, the present invention improves an optimal universal grounding system by adding a moisture collecting system to a state of the art grounding electrode, and further adding an ideal backfill. Thus, even dry soils can be adapted to provide an adequate ground.
The foregoing grounding objectives are achieved by providing a conventional tubular member of an electrically conductive material. The tubular member is filled with a selected metallic salt matched to the soil condition. The tubular member is then buried and surrounded with an osmotically conductive material such as the Grounding Augmentation Fill (GAF™). The lower portion of the tubular member is a reservoir containing a saturated solution of that salt. The lower portion has provisions for the overflow of the salt from that reservoir so as to maintain a wet interface between the electrode and the GAF™ or a GAF™/soil mixture.
Two or more conductive rings or collars maybe added to the conventional structure of the hollow tubular member. The rings are nominally twelve to thirty-six inches in diameter, flat, and composed of copper or other highly conduct
Dinkins Anthony
Lightning Eliminators & Consultants Inc.
Martin Rick
Patent Law Offices of Rick Martin P.C.
Walkenhorst W. David
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