Thermal Gas Sensor Amplitude-Phase Evaluation for Compact Analysis

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Solution Overview

Problem

Existing gas measurement systems are bulky and heavy, requiring multiple devices for pressure, flow, and gas analysis, and lack efficient integration for precise and rapid gas concentration determination.

Innovation Solution

An evaluation arrangement for a thermal gas sensor that combines information about detector signal amplitudes and phase differences to determine gas concentration and thermal diffusivity, using a heater and one or two detectors, with a method to control heating power and apply periodic signals for precise gas analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple separate devices are used for pressure measurement, flow measurement, and gas analysis, then measurement completeness is improved, but installation space and system weight increase

Engineering Contradiction:

Improvemeasurement completenessVSAvoidsystem weight

Core Design Contradiction:

Measurement precisionVSWeight of stationary object

Solution Approach 1:

The patent combines multiple measurement functions (pressure measurement, flow measurement, and gas analysis) into a single integrated sensor device. The sensor device includes a sensor element with a membrane that can detect pressure changes, flow-induced vibrations, and gas composition through thermal or optical methods, eliminating the need for multiple separate devices and reducing overall system weight and installation space.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The sensor device is designed with multi-functionality to perform pressure measurement, flow measurement, and gas analysis simultaneously. The membrane structure serves multiple purposes: it acts as a pressure-sensitive element, a flow-induced vibration sensor, and a barrier for gas composition analysis, allowing one device to replace multiple specialized instruments.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If multiple separate devices are used for pressure measurement, flow measurement, and gas analysis, then measurement completeness is improved, but installation space increases

Engineering Contradiction:

Improvemeasurement completenessVSAvoidinstallation space

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

3Device complexity

If conventional sensor systems are used, then system simplicity is maintained, but gas analysis speed and precision deteriorate

Engineering Contradiction:

Improvesystem simplicityVSAvoidgas analysis speed

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The patent employs periodic excitation signals to drive the membrane at its resonant frequency, enabling rapid gas analysis. By using oscillating pressure fields and periodic thermal or optical measurement cycles, the system achieves quick gas composition determination without requiring complex multi-step measurement procedures, thus improving analysis speed while maintaining relatively simple device architecture.

Inventive Principle:

Principle #19Periodic action

4Device complexity

If conventional sensor systems are used, then system simplicity is maintained, but gas concentration determination precision deteriorates

Engineering Contradiction:

Improvesystem simplicityVSAvoidgas concentration determination precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces conventional mechanical or purely thermal gas analysis methods with oscillating membrane-based detection. The membrane's vibration characteristics under periodic excitation provide enhanced sensitivity to gas composition changes, allowing precise gas concentration determination through measurement of vibration amplitude, frequency, or phase changes, while avoiding the need for complex mechanical measurement systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 compact and lightweight gas measurement with precise gas concentration and thermal diffusivity determination, minimizing installation space and reducing system weight while ensuring quick and accurate analysis.

Implementation Method 1

thermal gas sensor with at least one heater and at least one detector

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

at least one detector arranged in different distances to the heater

Methodology Applied

Scientific EffectThermal radiation detection: Thermal Radiation

Data Source

PatentUS12385862B2Evaluation arrangement for a thermal gas sensor, methods and computer programs

Publication Date: 2025.08.12 HAHN SCHICKARD GESELLSCHAFT FUR ANGEWANDTE FORSCHUNG EV

AI summary

Evaluation arrangement for a thermal gas sensor with at least one heater and at least one detector. The evaluation arrangement is configured to obtain information about an amplitude of a detector signal of a first detector, and information about a first phase difference between a heater signal and the detector signal of the first detector. In addition, the evaluation arrangement is configured to form as an intermediate quantity, dependent on the information about the amplitudes of the detector signal and dependent on the information about the first phase difference, a combination signal, and to determine information about a gas concentration or information about a thermal diffusivity of a fluid on the basis of the combination signal.