GB2377584A

GB2377584A - Position recording and relocation of buried installations

Info

Publication number: GB2377584A
Application number: GB0113550A
Authority: GB
Inventors: Andrew Richard Hiron
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-06-05
Filing date: 2001-06-05
Publication date: 2003-01-15
Also published as: GB0113550D0

Abstract

A feature such as a joint 12 of a pipe line is associated with a radio frequency tag 14 mounted on or close thereto, having a unique identification code. After closure of the trench, the code is read by a portable device and recorded with other data, including GPS data. To relocate the feature a detector 16 is used which emits an interrogation code, in the general recorded location of the feature 12. On receiving a valid interrogation signal from detector 16, the tag 14 emits a signal containing the unique identification code. Detector 16 compares this with the code of the feature sought and if the codes match a signal indicating detection is given by the detector 16.

Description

Position Recording and Relocation of Buried Installations This invention relates to position recording and relocation of buried installations, notably utility pipelines, conducts or cables with particular reference to important locations of such installations such as junctions, stop-clocks, connection boxes or joints.

The field of application includes water and gas mains, sewage and drainage conduits, electrical, telecommunication cables, and fibre optic cables, and also fuel pipelines.

Conduits, pipes and cables are usually buried below streets and sidewalk pavements, frequently alongside and crossing over the pipes, cables or conduits of other utilities, with several being present in any one street.

It is desirable, when an installation of this kind is assembled and buried in a trench, to record the path or progress of the installation of the pipeline or other installation together with the locations of features of particular importance or vulnerability to enable the line and the features to be relocated for repair or other access purposes.

Prior practice has been to map the installation manually by drawings or measurement with reference to a co-ordinate system, or to local features.

However, such recording is prone to error, and apparently permanent markers may be removed or relocated when street layouts are changed for example in response to changes in traffic requirements. More modern

techniques which attempt to utilise an absolute coordinate system such as GPS (Global Positioning Satellite) systems can only give an overall location accurate to a few metres in distance terms or covering several square metres in area terms.

Such accuracy is not sufficient for practical purposes since it may be necessary to excavate a substantial area of a busy highway to locate a feature, such as a joint in a pipeline, and the area may include the lines of several services including gas, water, electricity and telecommunications, any of which may be put at risk of damage by excavation to uncover a suspected fault in only one service.

GB-A-2300267 discloses apparatus for detecting underground installations wherein a tuned coil is provided at each of a plurality of specific features in a buried installation, the coil being fed from an a. c. signal applied to the installation. The tuned coil is adapted to be detected by a receiver which is capable of detecting the field generated by the field in response a. c. signal applied to the installation. This system does not however allow the precise location of a feature such as a splice or pipe joint to be pin pointed, at the time of installation, and a substantial area defined by reference to surface features, or GPS raw data, needs to be swept by the detector to locate the feature. Also, all features in an installation are likely to give the same response, being equipped with identical massproduced tuned coil apparatus so that there may be uncertainty as to

uncertainty as to whether the feature, eg. pipe joint detected, is the pipe joint which is to be attended to.

Clearly it would be advantageous to be able to accurately determine the location of a feature such as a pipe joint, junction, valve and its unique identity or the like from above ground without any need for exploratory excavation, to both speed the entire operation by locating the feature quickly, and by minimising the excavation required to the area needed to uncover and locate the feature.

It is an object of the invention to provide an improved method and apparatus for recording to the position and relocation of buried installations which will enable a substantial improvement in the accuracy and speed of location of features of buried installations.

According to the invention there is provided a method of recording the location of and enabling relocation of a feature of a buried installation, comprising mounting an member adapted to emit a modulated signal on or adjacent to said feature, recording unique identification data concerning said feature and member and storing said data in a central data store, and burying said installation and feature.

Relocation may be carried out by the use of detector means capable of detecting of said signal emitted by said member The electronically detectable member may comprise a member which generates a modulated magnetic effect which is detectable by detector

means adapted to detect such modulated magnetic effect from at least the surface of the ground covering the buried installation.

The electronically detectable member may comprise a radiofrequency tag, which on interrogation, emits a modulated (eg. digital) signal giving a unique identifying code for the feature concerned.

The invention also provides apparatus for enabling the relocation and detection of a feature of a buried installation, comprising an electronically member adapted to emit a modulated signal mounted on or adjacent to said feature and a detector means, adapted to detect said signal from at least the surface of the ground covering the buried installation.

A preferred embodiment of the invention will now be described by way of example with reference to the accompanying drawings wherein :- Figure 1 is a diagrammatic representation of an installation at the time of recording the position and other data concerning the feature; and Figure 2 is a diagrammatic representation of a detector being used to relocate the feature on a later occasion.

In accordance with a preferred embodiment of the invention, the invention may be applied to any desired feature of a buried installation, notably pipe joints, t-junctions, branch connections, and valves or stopclocks in the case of gas, water, or sewage pipes and conduits, and connectors, glands, cable joints, junction boxes, switches and the like in the case of electricity or telecommunications cables.

As illustrated, the invention is applied to a pipe joint in a water or gas pipeline. The section of pipeline shown comprises two lengths of pipeline 10,11 which are butt-jointed at 12.

The joint may be a simple end-to-end welded joint covered with a sleeve 13, or a more complex flanged joint possibly adapted to press an end of the pipe into the socket of the other and including seal rings and other devices.

The sleeve 13 carries, at the upper side of the pipe line a radio- frequency (RF) tag 14, which comprises a protective housing containing a radio frequency transmitter adapted to emit a preprogrammed code signal. To converse power, the transmitter is preferably only operable to transmit the code signal upon receipt of a valid interrogation signal.

The tag 14 is mounted on the pipe at the location of the joint 12 and the pipe is then buried by the filling in of the excavation in which it is located. A portable device 15 reads the unique identification code of the transmitter in tag 14, and this information is logged together with further data, including the date of installation, the contract work number, the identity of the contractor who installed the joint, the name of the supervisor the type and diameter of the pipe line, machine identification information where the joint has been carried out by an automated jointing machine, and the location of the joint as determined from global positioning satellite to whom 5 square metres (about 2 metres in linear terms).

The information is either entered into memory in the portable device 15, for subsequent transfer to a central memory store, or is transmitted to the central memory store by land line or radio modem data link.

To relocate the joint 12, the approximate position as determined by GPS is obtained from the central memory store, and a detector 16 is passed over the probable location of the joint 12 as in Figure 2. The detector 16 emits an interrogation code, which when detected by the tag 14 and found to be valid (to avoid depletion of batteries by responding to different codes emitted by corresponding devices of other utilities, and also to avoid confusion which would arise if all interrogation codes were responded to) emits its unique identity code. This is compared by the detector 16 with the code for the joint or other feature being sought and detection is confirmed by a signal such as a sound and/or light signal or a message on a display screen.

After detection and confirmation any required excavation for access to the joint 12 can be carried out in the correct position without any need for exploratory digging over any substantial area.

Using the method and apparatus according to the invention, considerable advantages can accrue to the parties involved in the installation and maintenance of pipelines and other utilities.

A central data base can be created and maintained of all new and replacement installations, and the information on the time and location of

all features such as joints, valves, branches etc. recorded to any desired accuracy. Defective features may be flagged, and action taken to ensure rectification. The activities of particular jointing machines or work parties may be monitored to ensure that quality and promptness are maintained and to identify trends. Finally, extremely accurate location data is available to enable inspectors to go to the exact joint location and check for leaks etc..

If a joint fails within a certain period then the contractor can be identified and made to remedy the fault.

Manufactures and hirers of jointing machines may benefit from being able to monitor the performance of specific machines, ensuring that work standards and safety requirements are met, and machines can be kept track of as to their location by GPS data logged with each completed joint.

Contractors will equally be able to monitor the performance of pipe laying work parties in terms of both quantity and quality, identify lost plant, and manage their machine fleets to ensure servicing and safety standards. Also joints and pipes and other features needing to be re-excavated may be accurately located to reduce time and expense in digging in wrong locations. As a result they should be able to sell their services on performance as well as price.

The means for carrying the radio frequency tag 14 may be constructed at the height required by regulation for laying of warning tape above a buried pipe. Non compliance can again be monitored a nd the

contractor responsible identified.

I

Claims

1. A method of recording the location of and enabling relocation of a feature of a buried installation, comprising mounting an electronically detectable member adapted to emit a modulated signal on or adjacent to said feature, recording unique identification data concerning said feature and electronically detectable member and storing said data in a control data store, and burying said installations and features.

2. A method according to claim 1, comprising the additional step of relocating the feature by the use of detector means capable of detecting said signal emitted by said electronically detectable member.

3. A method according to claim 1 or 2 wherein the electronically detectable number comprises a member which generates a modulated magnetic effect, from at least the surface of the ground covering the buried installation.

4. A method according to claim 3 wherein the electronically detectable member comprises a radio-frequency tag, which on interrogation, emits a modulated signal giving a unique identifying code for the said feature.

5. A method according to claim 4 wherein the radio frequency tag comprises a protective housing containing a radio frequency transmitter adapted to emit a pre-programmed code signal.

6. A method according to claim 5 wherein the detector means includes means for emitting an interrogation code, means for receiving the code signal from the radio-frequency tag, means for comparing the signal with

a code corresponding to the feature to be relocated, and means for providing a signal to confirm that the code received corresponds to that for the feature.

7. A method according to claim 1, wherein the data recorded includes, the unique identification included in said modulated signal of said electronically detectable member, and the location of the feature as determined from Global positioning satellite.

8. A method according to claim 1 wherein the identification code has an alternate code which is enabled upon detection of a leak by associated sensing apparatus.

9. Apparatus for enabling the relocation and detection of a feature of a buried installation, comprising an electronically detectable member adapted to emit a modulated signal mounted on or adjacent to said feature, and a detector means, adapted to detect said signal from at least the surface of the ground covering the buried installation.

10. Apparatus according to claim 9 wherein said electronically detectable member comprises a member which generates a modulated magnetic effect which is detectable by detection means adapted to detect such modulated magnetic effect.

11. Apparatus according to claim 10 wherein said electronically detectable number comprises a radio-frequency tag which on interrogation emits a modulated signal giving a unique identifying code for the said feature.

12. Apparatus according to claim 11 wherein the radio-frequency tag comprises a protective housing containing a radio frequency transmitter adapted to omit a pre-programmed code signal.

13. Apparatus according to claim 12 wherein the detector means includes means for emitting an interrogation code, means for receiving the code signal from the radio frequency tag, means for comparing the signal with a code corresponding to the feature to be relocated and means for providing a signal to confirm that the code received corresponds to that for the feature.

14. Apparatus according to claim 9 including a portable device which includes means for recording the modulated signal of the electronically detectable member together with data including the location of the feature as determined from global positioning satellite, and for transferring the signal and data to a central data store.