Flexible Liquid-Metal Temperature Probe for Hotspot Localization

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Solution Overview

Problem

Existing temperature sensors, such as thermocouples and PN diodes, are too large and rigid to be arranged in confined spaces and cannot accurately detect temperature hotspots or their locations.

Innovation Solution

A flexible cable with a liquid metal path inside a sheath, where temperature-induced changes in electrical characteristics, like impedance, are measured using electromagnetic signals to determine both temperature and location of hotspots through time-domain reflectometry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If thermocouples or PN diodes are used as temperature sensors, then temperature measurement capability is provided, but the sensors are too large and rigid to be arranged in confined spaces

Engineering Contradiction:
Improvetemperature measurement capabilityVSAvoidadaptability to confined spaces
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent employs a flexible cable structure with a liquid metal path enclosed in a sheath, allowing the sensor to be bent and shaped to fit confined spaces while maintaining temperature sensing capability. The flexible cable can be routed through tight spaces and conform to complex geometries, directly resolving the contradiction between measurement capability and adaptability to confined spaces.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent utilizes the temperature-dependent electrical characteristics of liquid metal, specifically the change in impedance with temperature. This parameter change enables temperature measurement while the liquid metal's flexibility allows the sensor to adapt to confined spaces, resolving both aspects of the technical contradiction simultaneously.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If thermocouples or PN diodes are used as temperature sensors, then temperature measurement is provided, but the sensors cannot detect the exact location of temperature changes

Engineering Contradiction:
Improvetemperature measurement capabilityVSAvoidlocation information of temperature changes
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent divides the temperature sensing function along the length of the flexible cable into multiple segments. By emitting electromagnetic signals at different locations and detecting reflections, the system can identify which segment of the cable experiences temperature changes, thereby locating the hotspot position while maintaining temperature measurement capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces electromagnetic signals as an intermediary to transmit location information. The EM signals travel through the liquid metal path and provide both temperature data and spatial information about where temperature changes occur, eliminating the loss of location information while preserving temperature measurement capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If a flexible cable with liquid metal path is used, then adaptability to confined spaces is improved, but the complexity of the measurement system increases

Engineering Contradiction:
Improveflexibility and adaptability to confined spacesVSAvoidmeasurement system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The flexible cable serves multiple functions simultaneously: it acts as both the temperature sensing element and the signal transmission medium. The liquid metal path functions as both the temperature-dependent impedance sensor and the waveguide for EM signals, reducing the need for separate components and thereby limiting the increase in system complexity despite the flexible configuration.

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

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

Enables precise, flexible temperature monitoring in tight spaces by detecting temperature increases and their locations along the cable, allowing for efficient detection of hotspots.

Implementation Method 1

an externally induced temperature increase at a location along the length of the cable induces a change of electrical characteristics, in particular an increase of an impedance, of the liquid metal material at or near said location

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 2

an interface arranged on one end of the flexible cable, wherein the interface is designed for emitting an EM, electromagnetic, signal or wave into the liquid metal path

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 3

a capture unit configured to capture a reflection of said EM signal or wave

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP4300061B1Probe for conducting position resolved temperature measurements
Publication Date: 2025.10.29 ROHDE & SCHWARZ GMBH & CO KG
  • EP4300061B1 patent drawingFigure 1
  • EP4300061B1 patent drawingFigure 2a~2b
  • EP4300061B1 patent drawingFigure 3

AI summary

The invention relates to a probe (10) for conducting position resolved temperature measurements, comprising a flexible cable (15), wherein the flexible cable (15) comprises a sheath (11) surrounding an elongated channel, and a liquid metal material (12) disposed in the elongated channel forming a liquid metal path; wherein an externally induced temperature increase at a location along the length of the cable (15) induces a change of electrical characteristics, in particular an increase of an impedance, of the liquid metal material at or near said location. The probe (10) further comprises electrical terminals (13a, 13b) arranged on both ends of the flexible cable (15), wherein the electrical terminals (13a, 13b) are designed for a measurement of an electrical parameter of the liquid metal path; and an interface (14) arranged on one end of the flexible cable (15), wherein the interface (14) is designed for emitting an EM, electromagnetic, signal or wave into the liquid metal path.