Electricity: measuring and testing – Fault detecting in electric circuits and of electric components – Of individual circuit component or element
Patent
1986-07-03
1987-08-25
Eisenzopf, Reinhard J.
Electricity: measuring and testing
Fault detecting in electric circuits and of electric components
Of individual circuit component or element
324512, G01R 3112
Patent
active
046895523
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method and apparatus for detecting damage to a buried object covered with an electrically insulating layer over the outer periphery of a conductive member, such as a buried pipe member covered with a coating layer over the outer periphery of a steel pipe.
BACKGROUND OF THE INVENTION
In order to assure sound maintenance of pipes for transporting a fluid, it is essential to prevent surface corrosion as well as damage due to roadwork, etc.
For prevention of surface corrosion, a polyethylene lining for a layer covering the peripheral surface of a steel pipe, has recently been employed, thereby improving greatly the insulating performance or corrosion proof characteristic. Additional provision of electric anticorrosion assures prevention of surface corrosion.
However, damage to a steel pipe due to roadwork etc. on the road surface may cause a leak to occur, resulting in an accident. In order to prevent an accident, the managing agent of a buried object is required to perform extensive monitoring and management tasks such as by patrolling around the buried object or by being present at roadwork performed nearby the buried object. In this connection, immediate detection of pipe damage caused for some reason may help and assist such management, and is very effective for avoiding an accident.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method of rapidly detecting damage to a buried object.
It is another object of the present invention to provide a method of detecting the damaged portion of a buried object.
The present invention provides a method of detecting damage to a buried object comprising the steps of flowing an electric current through the conductive member of the buried object covered with an electrically insulating layer over the outer periphery of the conductive member, and comparing the value of such electric current with the value of another electric current measured at a different time so as to detect damage to the buried object.
The present invention also provides a method of detecting damage to a buried object comprising the steps of connecting one terminal of a power supply to the conductive member of a longitudinally extending buried object covered with an electrically insulating layer over the outer periphery of the conductive member, grounding the other terminal of the power supply, and making a comparison between values of electric currents flowing at the same time through the buried object at both sides in the longitudinal direction of the buried object with respect to the portion of the conductive member connected to said one terminal of the power supply so as to detect damage to the buried object.
Furthermore the present invention provides a method of detecting damage to a buried object comprising the steps of connecting one terminal of a power supply to the conductive member of a longitudinally extending buried object covered with an electrically insulating layer, grounding the other terminal of the power supply, making a comparison between values of electric currents flowing at the same time through the buried object at both sides in the longitudinal direction of the buried object with respect to the portion of the conductive member connected to said one terminal of the power supply, and measuring the size of damage to the buried object based on soil specific resistance and a difference of values of electric currents if such difference is detected.
The present invention still also provides a method of detecting damage to a buried object comprising the steps of connecting first terminals of power supplies to a first plurality of connection portions of the conductive member of a longitudinally extending buried object covered with an electrically insulating layer, grounding the other terminals of the power supplies, and making comparisons among values of electric currents flowing at the same time through the conductive member at a second plurality of portions among said first plurality of connection po
REFERENCES:
patent: 3800217 (1974-03-01), Lowrance
patent: 3916298 (1975-10-01), Ulrich
patent: 4063161 (1977-12-01), Pardis
patent: 4099117 (1978-07-01), Erath
Kadoi et al, Studies on Soil Corrosion of Metallic Materials (Part 1) Fundamental Experiment on Soils, 1966, pp. 10-18.
Fujii Akihiko
Tsuka Masahiro
Eisenzopf Reinhard J.
Harvey Jack B.
Osaka Gas Company Ltd.
LandOfFree
Method and device for detecting insulation damage to a buried ob does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and device for detecting insulation damage to a buried ob, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and device for detecting insulation damage to a buried ob will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1925056