Underground Utility Surveying Device with Compensation Coils

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Solution Overview

Problem

Existing underground utility detection devices face challenges in accurately locating utilities without a naturally occurring electrical current, requiring additional equipment and often resulting in low signal-to-noise ratios and reduced accuracy due to environmental and mechanical factors.

Innovation Solution

A mobile detection device with integrated emitter coils and receiver coils, arranged for maximum coupling, emits an electromagnetic field to induce currents in utilities, and uses a compensation unit to nullify direct influences, improving signal detection and robustness against environmental conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an emitter is integrated into the detection device to induce currents in non-current-carrying utilities, then the detection capability for non-current-carrying utilities is improved, but the signal-to-noise ratio deteriorates due to the strong excitation field from the emitter

Engineering Contradiction:
Improvedetection capability for non-current-carrying utilitiesVSAvoidsignal-to-noise ratio
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent converts the harmful strong excitation field from the emitter into a beneficial signal by using a compensation coil to generate an opposing field that cancels the direct coupling. This allows the system to tolerate and even utilize the strong excitation field while eliminating its harmful direct coupling effects, thereby improving detection capability without sacrificing signal-to-noise ratio

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The compensation coil generates an opposing magnetic field in advance to counteract the direct coupling from the emitter before it interferes with the detection coils. This preliminary anti-action prevents the harmful effect from manifesting, allowing the system to operate with integrated emitters while maintaining reliable signal detection

Inventive Principle:
Principle #9Preliminary anti-action

2Adaptability or versatility

If additional external equipment is used to detect utilities without naturally occurring current, then the detection capability is improved, but the device complexity increases

Engineering Contradiction:
Improvedetection capability for utilities without naturally occurring currentVSAvoidequipment requirements
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the emitter and detector functions into a single integrated device. The emitter coils and detection coils are combined in the same housing, eliminating the need for separate external equipment. This integration maintains full detection capability while significantly reducing device complexity and operational burden

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The detection device achieves multi-functionality by incorporating both emitter and detector capabilities in a single unit. This universal device can detect both current-carrying utilities (using passive detection) and non-current-carrying utilities (using active induction), replacing the need for multiple specialized devices

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If the emitter and receiver coils are arranged for maximum coupling, then the signal strength is improved, but the direct coupling noise from the emitter to receiver increases

Engineering Contradiction:
Improvesignal strengthVSAvoiddirect coupling noise
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful direct coupling noise into a useful signal by using the compensation coil to generate an opposing field that cancels the direct coupling. This allows the system to maintain maximum coupling geometry for strong signals while eliminating the harmful noise component through active compensation

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent introduces asymmetry in the coil arrangement by positioning the compensation coil specifically to counteract the direct coupling path from emitter to receiver. This asymmetric compensation strategy targets the harmful direct coupling while preserving the symmetric maximum coupling geometry for signal induction

Inventive Principle:
Principle #4Asymmetry

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

The device effectively detects and locates both current-carrying and non-current-carrying utilities with enhanced accuracy and reliability, reducing the need for external equipment and improving signal quality by minimizing noise from the excitation field.

Implementation Method 1

an emitter for an electromagnetic field for each detection coils or loops into a classical detection device... This transmitted field will generate an electrical current in or around the utility to be detected

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

detect electromagnetic fields emitted by the nature of the utility itself... the depth or distance to a buried utility can therein be determined according to a difference in signal strength at two or more detectors or pickups

Methodology Applied
Scientific EffectElectromagnetic field detection: Electromagnetic Induction

Implementation Method 3

The detection device also comprises a compensation unit, built to apply an electrical signal to each of the transmitting loops... arranged to establish an individual compensation field by each of the transmitting loops... which - in particular at least substantially of virtually - nullifies direct influences of the excitation field at each of the detection coils

Methodology Applied
Scientific EffectMagnetic field compensation: Magnetic Field

Data Source

PatentEP3339913B1Underground utility surveying
Publication Date: 2023.10.25 CABLE DETECTION
  • EP3339913B1 patent drawingFigure 1~2
  • EP3339913B1 patent drawingFigure 3~4
  • EP3339913B1 patent drawingFigure 5~7

AI summary

The invention relates to a mobile detection device (1) for an evaluation of a depth value (13) from the device (1) to an occluded underground elongate utility line (10). The device (1) comprises at least a fist and a second detector unit (2a,2b) being arranged with a spacing (3) with respect to one another. Each of them comprising at least a detection loop (25a,25b) and corresponding transmitting loop (27a,27b), wherein the detection loop (25a,25b) and the corresponding transmitting loop (27a,27b) are arranged close together. The device (1) also comprises at least one excitation coil (4) for emitting an alternating electromagnetic excitation field (Be) with its emission direction substantially in line with the sensitivity direction of the detection loop (25a,25b). The device has an electronic signal evaluation unit for detecting the utility line (10) according to an electrical signal induced in the detection loops (25a,25b) and evaluating the depth value (13) according to a difference of the electrical signal in-between the detection loops (25a,25b). There is a compensation unit built to apply an electrical signal to the transmitting loops (27a,27b) for establishing a compensation field (Bta,Btb), which substantially nullifies influences of direct coupling residuals of the excitation field (Be) at the detection loops (25a,25b)