Railway Metal Sensor With Adjustable Magnetic Coupling

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Solution Overview

Problem

Existing metal part detection sensors for rail vehicles face challenges with electromagnetic compatibility (EMC), energy inefficiency, and the need for manual recalibration due to temperature and installation position influences, which limits their reliability and robustness.

Innovation Solution

A sensor system with an adjustable digital impedance magnetically coupled into the electrical oscillating circuit allows for dynamic adjustment of the detection range, improving EMC and reducing energy consumption by using high-impedance connections and high-frequency power supply, along with remote control functionality for adjustments and testing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If galvanic connection is used to switch passive elements on and off, then detection range can be adjusted, but electromagnetic compatibility deteriorates and electrical design options are limited

Engineering Contradiction:
Improvedetection range adjustmentVSAvoidelectromagnetic compatibility
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces a coupling coil as an intermediary element that magnetically couples the sensor coil to the resonant circuit. This magnetic coupling acts as a mediator that allows adjustment of the detection range by switching passive elements (resistors, capacitors) without creating direct galvanic connections, thereby maintaining electromagnetic compatibility while achieving the desired adaptability in detection range.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If circuits are continuously supplied with energy for regular operation, then operational readiness is maintained, but energy consumption increases and service life decreases

Engineering Contradiction:
Improveoperational readinessVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic action by supplying energy to the passive elements (resistors, capacitors) only when needed for detection range adjustment, rather than continuously. The control unit activates these elements on-demand based on detection requirements, which maintains operational readiness when needed while significantly reducing overall energy consumption and extending the service life of the circuits.

Inventive Principle:
Principle #19Periodic action

3Ease of operation

If sensor components are exposed to temperature and installation position influences, then installation flexibility is improved, but measurement precision deteriorates

Engineering Contradiction:
Improveinstallation flexibilityVSAvoiddetection accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent employs feedback mechanisms where the control unit continuously monitors the detection signals and adjusts the activation of passive elements (resistors, capacitors) accordingly. This feedback loop compensates for variations caused by temperature changes and installation position differences, maintaining measurement precision despite the installation flexibility provided by adjustable detection ranges.

Inventive Principle:
Principle #23Feedback

4Stability of the object's composition

If fixed electrical potentials are imposed on the oscillating circuit coil, then circuit stability is improved, but device complexity increases and EMC deteriorates

Engineering Contradiction:
Improvecircuit stabilityVSAvoidelectrical design options
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The coupling coil serves as a mediator that decouples the fixed electrical potentials from the oscillating circuit coil. By using magnetic coupling instead of direct electrical connection, the patent maintains circuit stability through controlled impedance while preserving electrical design flexibility and improving electromagnetic compatibility. The intermediary coupling coil allows the passive elements to be switched without imposing fixed potentials on the sensor coil.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 system enhances robustness against electromagnetic interference, reduces error rates, and increases availability by allowing multiple electrical potentials and minimizing parasitic effects, while enabling remote adjustments and energy savings, thus improving the overall reliability and longevity of the sensor system.

Implementation Method 1

The sensor coil forms an oscillating circuit with a capacitor and builds up an alternating magnetic field in its vicinity

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

A metal part of a train wheel penetrating into the effective range of the sensor coil dampens the oscillating circuit, since energy is withdrawn from it by the iron of the train wheel through eddy current losses

Methodology Applied
Scientific EffectEddy current losses: Eddy Currents

Implementation Method 3

an adjustable, preferably digital impedance, which is magnetically coupled into the electrical oscillating circuit, as a result of which the quality of the electrical oscillating circuit can be adjusted

Methodology Applied
Scientific EffectMagnetic coupling: Electromagnetic Induction

Data Source

PatentEP3521131B1Sensor, system and method for detecting metal parts
Publication Date: 2021.03.10 PINTSCH TIEFENBACH
  • EP3521131B1 patent drawingFigure 1

AI summary

The present invention relates to a sensor, a system, and a method for detecting metal parts, in particular metallic or semi-metallic wheels of railway vehicles, comprising: an electrical resonant circuit with at least one sensor coil which generates a magnetic field and at least one sensor capacitor, wherein the electrical resonant circuit has a quality factor, and an adjustable, preferably digital, impedance which is magnetically coupled into the electrical resonant circuit, whereby the quality factor of the electrical resonant circuit is adjustable, wherein the detection range for metal parts can be changed by adjusting the quality factor of the electrical resonant circuit; and wherein a DC voltage and/or a DC current of the electrical resonant circuit signals the detection of metal parts.