Buried Structure Proximity Detection via Induced Electromagnetic Fields

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Solution Overview

Problem

Existing methods for detecting buried structures like underground conduits and wiring systems are limited by the need for structures to emit electromagnetic fields, which restricts detection to live power lines and conductive materials, and often require direct access or connection, making it difficult to detect non-conductive or inaccessible services like plastic water conduits.

Innovation Solution

Introducing an alternating electrical current into the soil using electrodes connected to a current-source, which flows along buried structures and emits an electromagnetic field detectable by a mobile, insulated detection-unit, allowing for the detection of structures without natural electromagnetic emissions, including those made of non-conductive materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If electromagnetic field detection is used to locate underground structures, then detection capability is improved for live power supplies and conductive materials, but detection capability deteriorates for non-conductive materials and structures without natural electromagnetic fields

Engineering Contradiction:
Improvedetection capabilityVSAvoidapplicability to different structure types
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent introduces an intermediary current source that couples electrical current to the underground structure through conductive coupling. This intermediary device enables non-conductive structures to emit electromagnetic fields by inducing current through capacitive coupling or other indirect mechanisms, thereby expanding detection capability to all structure types while maintaining the electromagnetic field detection method's precision advantages.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the operational parameters of the structure by applying an external electrical signal at a specific frequency. This transforms the structure from a passive, non-emitting state to an active state where it emits electromagnetic fields. The detection system then detects these induced fields, enabling universal detection across conductive and non-conductive materials by dynamically altering the structure's electromagnetic properties.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If direct connection to service is made to emit electromagnetic field, then detection capability is improved for non-naturally emitting structures, but ease of operation deteriorates due to difficulty of locating and connecting to hidden or inaccessible services

Engineering Contradiction:
Improvedetection capabilityVSAvoidease of connection
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent introduces an intermediary coupling mechanism that eliminates the need for direct physical connection to the service. The current source couples energy to the structure through the ground or air using capacitive or inductive coupling, acting as a mediator between the detection system and the target structure. This intermediary approach maintains detection precision while dramatically improving ease of operation by removing the need to locate and access service outlets.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical connection system (physical access and direct wiring) with an electromagnetic field-based coupling system. Instead of mechanically connecting to the service, the system uses electromagnetic induction and capacitive coupling through the ground, substituting a complex mechanical access requirement with a simpler wireless or ground-coupled electromagnetic interaction.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If electromagnetic field detection is used for metallic services, then detection capability is improved, but adaptability deteriorates for non-metallic conductive structures like plastic water conduits

Engineering Contradiction:
Improvedetection capabilityVSAvoiddetection range across materials
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent changes the electromagnetic parameters by applying signals at optimized frequencies and using current coupling methods that induce fields in non-metallic conductive structures. Plastic water conduits containing water become detectable because the water provides ionic conductivity, and the applied current induces measurable electromagnetic fields in these previously undetectable structures, expanding material adaptability while maintaining detection precision.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method enhances the detectability and accuracy of buried structures, enabling efficient avoidance of damage during excavation by providing real-time proximity information, usable on various ground conditions and with excavating equipment, and is applicable to a wide range of conductive structures.

Implementation Method 1

generating an alternating electrical current of a desired frequency and strength by a current-source, introducing the electrical current into the structure so that an electromagnetic field is emitted by the current-carrying structure

Methodology Applied
Scientific EffectElectromagnetic field emission: Electromagnetic Induction

Implementation Method 2

detecting the time-variable electromagnetic field by a mobile detection-unit above ground that is electrically insulated from the ground and determining the proximity of the structure to the detection-unit according to the detected electromagnetic field

Methodology Applied
Scientific EffectElectromagnetic field detection: Electromagnetic Induction

Data Source

PatentEP2457113B1Method and system for detecting the proximity of a conductive, buried structure
Publication Date: 2020.06.10 LEICA GEOSYSTEMS AG
  • EP2457113B1 patent drawingFigure 1
  • EP2457113B1 patent drawingFigure 2
  • EP2457113B1 patent drawingFigure 3

AI summary

The invention concerns a proximity detection of buried conductive structures before or while digging in areas being excavated. By means of the enclosed methods, devices, and setups, the ability and accuracy of the detection of underground structures, such as conduits, pipes, etc. is improved by conductively applying a current into the structure through the soil. The thereby emitted electromagnetic field is detected by a movable detection- unit over ground. According to this electromagnetic field the detection-unit can determine the proximity of the structure and issue a warning signal. This warning signal helps an operator of an earth moving machine to avoid a collision with the structure.