Method and arrangement for determining soiling in the optical path of an optical sensor for observing a flame in a combustion chamber and computer program product

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Solution Overview

Problem

Existing methods for detecting and compensating for contamination in the light path of optical sensors in combustion chambers of heating appliances, particularly those using hydrogen-containing fuel gas, are complex and increase overall system complexity due to the need for additional radiation sources.

Innovation Solution

A method that compares measured values from an optical sensor with stored values under defined operating conditions to detect contamination, allowing simultaneous detection and compensation without interrupting flame observation, using a comparator and correction module to adjust for deviations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If additional radiation sources are used to detect contamination in the light path, then contamination detection capability is improved, but device complexity increases

Engineering Contradiction:
Improvecontamination detection capabilityVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The optical sensor serves dual functions: it monitors the flame during normal operation and detects contamination in the light path. By using the same sensor for both purposes, the patent eliminates the need for separate radiation sources and detection systems, thereby reducing device complexity while maintaining contamination detection capability

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

Solution Approach 2:

The system uses its own operational characteristics (flame radiation) to detect contamination. The optical sensor measures the flame's light properties during normal operation, and any deviation from expected measurements indicates contamination. This self-service approach avoids adding external radiation sources, resolving the contradiction between detection capability and system complexity

Inventive Principle:
Principle #25Self-service

2Measurement precision

If contamination detection is performed separately from flame observation, then detection accuracy is improved, but productivity decreases due to interrupted operation

Engineering Contradiction:
Improvedetection accuracyVSAvoidoperational continuity
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The optical sensor continuously monitors the flame throughout operation without interruption. Contamination detection occurs simultaneously with flame observation by analyzing the flame's radiation characteristics in real-time, ensuring both continuous productivity and accurate detection without requiring separate measurement phases

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent merges flame observation and contamination detection into a single simultaneous process. The optical sensor performs both functions concurrently by measuring flame radiation properties, eliminating the need to interrupt operation for separate detection, thus maintaining productivity while ensuring detection accuracy

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If optical sensors are used for flame monitoring in hydrogen-containing fuel gas, then measurement capability is improved, but reliability decreases due to contamination susceptibility

Engineering Contradiction:
Improveflame monitoring capabilityVSAvoidcontamination resistance
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system continuously monitors flame radiation characteristics and compares measurements against expected values. When contamination alters the light path and changes measurement signals, the system detects these deviations and can trigger warnings or shutdowns, maintaining reliability by compensating for contamination effects through continuous feedback monitoring

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent implements preliminary contamination detection by continuously monitoring light path transmission during operation. By detecting contamination early through radiation measurement deviations, the system can take preventive action before contamination severely impacts flame monitoring reliability, thus maintaining measurement capability while addressing contamination susceptibility

Inventive Principle:
Principle #10Preliminary action

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 and compensation of contamination in the light path, ensuring accurate flame monitoring and combustion control, particularly in hydrogen-based systems, with reduced complexity and increased safety by integrating detection with regular operation.

Implementation Method 1

an optical sensor (for the visible, but especially also for the ultraviolet range of light) for flame monitoring

Methodology Applied
Scientific EffectRadiation detection: Electromagnetic Induction

Implementation Method 2

an electromagnetic radiation source, hereinafter referred to as a light source or luminaire, to check the cleanliness of the light path. Radiation emitted by the electromagnetic radiation source can be sent through the window

Methodology Applied
Scientific EffectElectromagnetic radiation emission: Electromagnetic Induction

Implementation Method 3

Radiation emitted by the electromagnetic radiation source can be sent through the window (whose cleanliness is to be checked) onto an external reflector and from there reflected back to the sensor

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP4215817B1Method and arrangement for determining soiling in the optical path of an optical sensor for observing a flame in a combustion chamber and computer program product
Publication Date: 2026.03.18 VAILLANT GMBH(DE)
  • EP4215817B1 patent drawingFigure 1

AI summary

The invention relates to a method and an arrangement for detecting contamination (18) in a light path (17) from a flame (7) in a combustion chamber (2) to an optical sensor (9), wherein measured values ​​from the optical sensor (9) at at least one defined state of the flame (7) are compared with a stored measured value for this state of the flame (7), and if there is a deviation above a predefinable difference, a conclusion is drawn about the presence of contamination (18) in the light path (17). The present invention enables the detection of contamination (18) in the light path (17) from the flame (7) to the optical sensor (9) and an estimation of the remaining trouble-free operating time of a heating device (1), as well as the compensation of contamination (18) by correcting current measured values.This will increase safety, especially for heating appliances powered by hydrogen or hydrogen-containing fuel gas (1), and allow necessary maintenance measures to be identified early.