Method for buried service detection using a mains socket

Patent metadata

Field	Value
Publication number	US-9594183-B2
Application number	US-201314389332-A
Country	US
Kind code	B2
Filing date	Mar 14, 2013
Priority date	Mar 30, 2012
Publication date	Mar 14, 2017
Grant date	Mar 14, 2017

Abstract

The invention concerns a method for detecting buried services by electromagnetic means with introducing an artificially generated electrical detection signal indirectly via soil to the buried service, detecting an electromagnetic field originating from the introduced underground detection signal, which is preferably following along the buried services, by a mobile detection unit above ground, and determining the proximity of the structure to the detection unit according to the detected electromagnetic field of the detection signal. Therein, the soil conducted detection signal is supplied via a mains socket.

First claim

What is claimed is:

1. A method for detecting buried services by electromagnetic means with
introducing an artificially generated electrical detection signal as an alternating electrical current of a desired frequency from a current-source, indirectly via soil to the buried service,
detecting an electromagnetic field originating from the introduced underground detection signal, which is floating along the buried services, by a mobile detection unit above ground, wherein the unit is electrically insulated from the ground, and
determining the proximity of the buried services to the detection unit according to the detected electromagnetic field of the detection signal,
wherein,
the soil conducted detection signal is supplied via a mains socket, in such a way that a flow path of the detection signal is:
from the current-source to a first conductor of mains wiring at the socket,
via the first conductor from the socket to a remotely located substation of a mains supply network, where the first conductor is remotely grounded, so that the detection signal is conducted to soil material,
floating through the soil material and following at least a part of the buried service as path of least resistance within the soil material,
from the buried service through soil material to a domestic earthing point, where a second conductor of mains wiring is grounded, and
via the second conductor to the mains socket and back to the current-source.

2. The method according to claim 1 , wherein the method comprises applying the detection signal inbetween a neutral and an earth-conductor of the socket, wherein the electrical circuit of the detection signal is closed by a to be detected soil conducted current from a domestic, local earthing of the earth-conductor to a remote earthing of the neutral conductor at a substation of a mains supply network.

3. The method according to claim 1 , wherein the method comprises applying the detection signal inbetween a live- and an earth-conductor of the socket, wherein the electrical circuit of the detection signal is closed by a to be detected soil conducted current from a domestic, local earthing of the earth-conductor to a remote earthing of a neutral point of a transformer for the live-conductor at a substation of a mains supply network.

4. The method according to claim 1 , wherein
the detecting comprises the buried service, being a non-mains-supply-service which is separate of the mains supply network and unconducted to an electrical circuit of the mains socket, according to the soil conducted detection signal floating along at least part of the buried service.

5. The method according to claim 1 , wherein the method comprises an indicating of an electrical current level of the detection signal being within a desired range or a gauge indicating the electrical current level.

6. The method according to claim 2 , wherein the method comprises an indicating of whether the detection signal is supplied via the socket's Live or via Neutral or via both of those wires.

7. The method according to claim 1 , wherein the method comprises an introducing of the detection signal with a voltage value above a low voltage safety level, wherein the detection signal has a voltage above 50 volts.

8. The method according to claim 1 , wherein
modulating the introduced detection signal with a defined modulation signal according to a predefined sequence.

9. The method according to claim 1 , wherein the second conductor of mains wiring is a protective earth conductor.

10. The method according to claim 1 , the method comprises detecting a plurality of buried services with the detection signal, wherein at least one buried service is electrically passive and has no naturally occurring electrical signal.

11. The method according to claim 1 , wherein the detection signal has a frequency in the range of 5-300 kHz.

12. The method according to claim 1 , wherein the detection signal has a frequency of about 33 kHz.

13. The method according to claim 1 , wherein the detection signal is an alternating signal of a first frequency which is modulated by a modulation signal of a defined second frequency or according to a modulation sequence predefined in a means which is generating the detection signal.

14. A method for detecting buried services by electromagnetic means with
introducing an artificially generated electrical detection signal as an alternating electrical current of a desired frequency from a current-source, indirectly via soil to the buried service,
detecting an electromagnetic field originating from the introduced underground detection signal, which is floating along the buried services, by a mobile detection unit above ground, wherein the unit is electrically insulated from the ground, and
determining the proximity of the buried services to the detection unit according to the detected electromagnetic field of the detection signal,
wherein,
the soil conducted detection signal is supplied via a mains socket, in such a way that a flow path of the detection signal is:
from the current-source to a second conductor of mains wiring at the mains socket of a property, where the second conductor is grounded at a domestic earthing point, so that the detection signal is conducted to soil,
floating through the soil and following at least a part of the buried service as path of least resistance within the soil,
from the buried service through the soil to a first remotely grounded conductor of mains wiring at a substation of a mains supply network, where the first remotely grounded conductor is grounded, and
via the first remotely grounded conductor from the substation of a mains supply network to the mains socket at the property and back to the current-source.

Assignees

• Leica Geosystems Ag
• Cable Detection Ltd

Inventors

• Branson Simon

Classifications

• G01V3/02

  operating with propagation of electric current · CPC title

• G01V3/088 Primary

  operating with electric fields (G01V3/082 takes precedence) · CPC title

• G01V3/081 Primary

  the magnetic field is produced by the objects or geological structures (characterised by the method of magnetic field measurement G01R33/00) · CPC title