Optical Hydrogen Detection in Heating Devices

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Solution Overview

Problem

Conventional sensor technologies fail to reliably detect and quantify hydrogen in heating devices, particularly in hydrogen-fueled systems, due to the invisible nature of hydrogen flames and differences in heat radiation, making it challenging to monitor stable flames, combustion air-to-fuel ratios, hydrogen leaks, and unburned hydrogen in exhaust gases.

Innovation Solution

A method and arrangement using optical sensors with filters to observe specific emission and absorption lines of atomic and molecular hydrogen, allowing for selective detection and quantification of hydrogen through intensity measurement, even in high-temperature environments, by employing wavelength-sensitive sensors and light sources to distinguish hydrogen presence and concentration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional sensors are used for detection, then the sensors are simple and robust, but they cannot reliably detect hydrogen presence and concentration

Engineering Contradiction:
Improvehydrogen detection reliabilityVSAvoidsensor system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces conventional mechanical/electrical sensors with an optical detection system that uses light sources, optical filters, and photodetectors to detect hydrogen through its characteristic emission and absorption spectral lines. This substitution enables reliable hydrogen detection by exploiting hydrogen's unique optical properties rather than relying on conventional sensing mechanisms that fail with hydrogen.

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

Solution Approach 2:

The patent changes the detection parameter from general thermal or electrical properties to specific optical spectral parameters (emission lines at 656.3nm, 486.1nm, 434.0nm, 410.2nm and absorption lines in the ultraviolet and visible range). By monitoring these specific wavelength parameters, the system can selectively and reliably detect hydrogen presence and concentration even in complex combustion environments.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If optical sensors with filters are used, then hydrogen detection selectivity is improved, but the system complexity increases

Engineering Contradiction:
Improvehydrogen detection precisionVSAvoidoptical system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces optical filters as intermediary components that selectively transmit only the specific wavelengths corresponding to hydrogen's emission or absorption lines while blocking other wavelengths. These filters act as mediators between the light source/detector and the hydrogen target, enabling precise wavelength selection and thereby achieving high measurement precision for hydrogen detection.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If conventional flame detection methods are used, then the system is simple, but the invisible hydrogen flame cannot be detected

Engineering Contradiction:
Improveflame detection reliabilityVSAvoiddetection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent detects hydrogen flames by monitoring their characteristic color signatures in the optical spectrum. Hydrogen emits light at specific wavelengths (red at 656.3nm, blue-green at 486.1nm, blue-violet at 434.0nm, and violet at 410.2nm) when combusted. By using optical filters tuned to these wavelengths and photodetectors to measure the intensity of light at these colors, the system can reliably detect the invisible hydrogen flame through its spectral color characteristics.

Inventive Principle:
Principle #32Color 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

Enables reliable detection of hydrogen for leak monitoring, ensuring safe ignition and preventing unburned hydrogen in exhaust gases, while providing a simple and robust solution for everyday operation of hydrogen-fueled heating devices.

Implementation Method 1

at least one emission line of atomic and/or molecular hydrogen with a known wavelength is observed, and the presence of hydrogen is inferred from its intensity

Methodology Applied
Scientific EffectEmission spectrum: Luminescence

Implementation Method 2

at least one absorption line of atomic and/or molecular hydrogen with a known wavelength is observed

Methodology Applied
Scientific EffectAbsorption spectrum: Absorption Spectroscopy

Data Source

PatentEP3995817B1Method and assembly for detecting hydrogen in a heater operable with hydrogen or hydrogen-containing fuel gas
Publication Date: 2024.08.14 VAILLANT GMBH(DE)
  • EP3995817B1 patent drawingFigure 1

AI summary

The invention relates to a method for observing the presence of molecular and/or atomic hydrogen at at least one predefinable measuring point (19; 21; 23) of a heating device (1) comprising a burner (7) operated with hydrogen or a hydrogen-containing fuel gas, wherein at least one optical emission and/or absorption line of a known wavelength of atomic and/or molecular hydrogen is observed and the presence of hydrogen is inferred from its intensity. It also relates to a corresponding arrangement for detecting the presence of molecular and/or atomic hydrogen at at least one predefinable measuring point (19; 21; 23) of a heating device (1) comprising a burner (7) operated with hydrogen or a hydrogen-containing fuel gas, wherein a wavelength-sensitive sensor (11.1, 13.1; 11.2, 13.2; 11.3, 13.1) is used.3) for at least one wavelength of an emission and/or absorption line of atomic and/or molecular hydrogen, which is configured to measure the intensity of the incident radiation of this wavelength and/or its change. The present invention makes it possible to detect the presence of hydrogen due to leaks and/or incomplete combustion and/or to determine a favorable time for ignition of the burner using simple and robust instrumentation on a heating device.