Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
  • G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
  • G01V3/02—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with propagation of electric current
  • G01V3/06—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with propagation of electric current using ac

Definitions

• the present invention relates to a method of tracing sub ⁇ terranean metallic conductors by using direction-finding equipment and a number of subterranean markers and spe- cial equipment for the implementation of the method.
• markers are placed along a subterranean wire close to joints or branches.
• the markers are embodied as a flat coil, which is connected in series to a capacitor and has a natural frequency corresponding to a frequency applied to the wire from a transmitter that is connected to the wire.
• the markers are designed as a closed unit, that has neither connection to earth nor to any other conductors.
• the markers are buried in the ground with the coil hori- zontal.
• a receiver is used with an aerial coil that is able to pick up the signal that is transmitted from the w...re.
• a buried marker is identified by means of a combined transmitter/receiver unit, in which the transmitter/receiver part is connected in such a way that a minimum connection is obtained between the transmitter and the receiver.
• the marker or markers are designed as a closed unit that neither has connection to earth nor to any other conduc ⁇ tors and are tuned to a frequency corresponding to the frequency of the transmitter.
• the marker is localized at the maximum deflection on the receiver.
• the state of splicings on cables can be localized and re- gistered by installing an electronic marker on the spli ⁇ ce.
• an electro ⁇ magnetic signal is induced into the cable.
• the signal can be registered on the receiver and when the transmitter- /receiver unit is placed over the marker, the received signal will either be at a maximum or minimum depending upon the construction of the electronic marker.
• the mar ⁇ kers are constructed in such a way that their natural frequency varies according to pressure, temperature and humidity in the splicing, so that the state of these va ⁇ riables can be registered.
• warning nets incorporating an isolated metallic tracing wire are now laid along the conductor.
• the localization of such a warning net implies that the tracing wire has contact points on the surface of the ground or that a hole has been dug right down to the wire.
• the purpose of the present invention is to indicate a method for the localization of subterranean conductors or wires whereby the disadvantages of the known methods are avoided.
• Claim 2 describes an oscillating or coupling circuit, which is used in the implementation of the method ac ⁇ cording to claim 1.
• Claim 3 describes an embodiment of a coupling circuit, which is used by in the method according to the inven ⁇ tion.
• Claim 4 describes a particular embodiment of the coup ⁇ ling circuit, by means of which an establishment of earth ⁇ ing is avoided.
• Claim 5 describes a particular kind of connection of the coupling circuit to an electric cable that is to be tra- ced.
• fig. 2 is a picture corresponding to the one shown in fig. 1, but with another kind of earthing,
• fig. 3 is a p .ture corresponding to the one shown in fig. 1, but with a third kind of earthing,
• fig. 4 is a picture corresponding to the one shown in fig. 1, but here the coupling circuit is connected to an electric cable,
• fig. 5 schematically shows a section through a coupling clamp for use in connection with the cable connection shown in fig. 4,
• fig. 6 schematically shows a section through an aerial coil for a coupling circuit used at the implementation procedure of the method according to the invention.
• fig. 7 shows a section at the line I - I in fig. 6.
• an oscilla- ting or coupling circuit has been buried a bit below ter ⁇ rain 2, and it is directly connected to a conductor or wire 3, which is to be localized.
• the coupling circuit 1 is tuned to a frequency in the range of 20 150 kHz.
• the coupling circuit 1 is localized by means of the receiver part in a transceiver 4, consisting of a combined trans ⁇ mitter/receiver part, and is then placed on the surface of the ground 2 approximately vertically over the coup ⁇ ling circuit 1.
• the coupling circuit is constructed in such a way that in the mentioned position of the trans- DCver 4 , it has a maximum coupling efficiency to the transceiver.
• the transceiver 4 is then tuned to transmit at a frequency corresponding to the tuned frequency of the coupling circuit 1.
• the wire 3 can then be traced by means of an independent direction find ⁇ ing receiver 5 tuned to the applied frequency.
• the coupling circuit 1 is placed in a watertight box 6 and it includes an aerial coil 7, which mainly is con ⁇ structed as a single-layer coil and a tuning component as a capacitor 8.
• the induced signal in the coupling circuit 1 is transmitted through a component 9 that in its simp ⁇ lest form can be a capacitor, but it can also be an os ⁇ cillating circuit tuned to the applied frequency of the wire 3, which is to be traced and is connected to the coupling circuit 1 at a terminal 10.
• the coupling circuit is earthed by the connection of an earth wire 11 to a terminal 12.
• the signal is transmitted to earth and back again to the point of earthing of the coupling circuit.
• the coupling circuit can be tuned to a specific chosen natural frequency, which is then kept constant e.g. the coil is mounted in a movable position in relation to the core 16.
• the coupling circuit 1 can be embodied with an external tube 13, in which another tube or field spool 14 is concentrically mounted, upon which the coil 7 is wound. Concentrically in the tube 14 a third tube 15 is placed. A number of ferrite-rods 16 can be placed in between the gap of the cases 14 and 15 , which e.g. might be cylindrical. The ferrite-rods are at ⁇ tached to the tube 15 and they are placed close to the inside wall of the field spool 14. The field spool 14 can be moved in an axial direction for fine-tuning. As shown in fig. 2 the earth terminal 12 of the coupling circuit 1 can be connected to another conductor 17, e.g. the metal conductor in a warning net.
• another conductor 17 e.g. the metal conductor in a warning net.
• the earth connection of the coupling circuit 1 can also be established by connecting a flat plate 18 of electrically conductive material to the ter ⁇ minal 12, which is built into the box 6 of the coupling circuit 1 close to and parallel to one of the sides of the box, e.g. the base 19.
• the coupling circuit 1 can be connec ⁇ ted to an electric wire 3 by means of a plate 20, mounted in such a way that it has a capacitive transition to the wire 3.
• the plate 20 can be flexible, so that it is pos ⁇ sible to clamp it on the outside of the wire 3 and, as shown in fig. 5, it can be embedded in an insulating ma ⁇ terial 21 that has less thickness of material on the side facing the wire 3 than on the side facing earth.
• fibre op ⁇ tics may have one code, telecom cables another etc.
• the transmit ⁇ ted bearing power can be varied.
• the coupling circuits can mechanically have different embodiments depending upon whether the coupling circuits have to protect a number of short domestic cab ⁇ les in houses in e.g. a residential neighbourhood or if localization possibility is wanted over longer stretch- es.
• the box 6 of the coupling circuit and the coupling cir ⁇ cuit itself are mounted in or made of a synthetic mate ⁇ rial, which is long-term resistant to influences from the surrounding earth.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Geology (AREA)
• Remote Sensing (AREA)
• Physics & Mathematics (AREA)
• General Life Sciences & Earth Sciences (AREA)
• General Physics & Mathematics (AREA)
• Geophysics (AREA)
• Geophysics And Detection Of Objects (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=8108657

Family Applications (1)

Country Status (2)

Cited By (1)

Citations (8)

• 1990
  • 1990-08-06 DK DK186890A patent/DK164610C/da not_active IP Right Cessation
• 1991
  • 1991-07-17 WO PCT/DK1991/000210 patent/WO1992002834A1/en unknown

Patent Citations (8)

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