Optical Sensor Tube Arrangement for Combustion Chamber Monitoring

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Solution Overview

Problem

Existing optical sensor systems for monitoring hydrogen combustion in heaters face challenges with contamination, heat exposure, and reduced light signal quality due to air cooling and direct heat conduction, which affects their reliability and longevity.

Innovation Solution

An optical sensor arrangement is positioned outside the combustion chamber window with a tube connecting the sensor to the window, providing a protective path for optical rays and minimizing direct contact, using a mechanically stable tube with varying thermal conductivity to manage heat transfer and prevent contamination, while allowing air flow for cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the optical sensor is positioned close to the flame and combustion chamber for clearer flame signal, then the measurement precision is improved, but the sensor is exposed to excessive heat and contamination

Engineering Contradiction:
Improveflame signal clarityVSAvoidheat exposure and contamination
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

A tube is introduced as an intermediary component between the optical sensor and the combustion chamber window. This tube serves as a protective barrier that transmits optical radiation from the flame to the sensor while isolating the sensor from direct heat exposure and contamination by combustion products and dust particles.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The optical path is segmented into distinct zones: the combustion chamber interior, the tube passage, and the sensor housing. This segmentation allows the sensor to be positioned outside the high-temperature zone while maintaining an unobstructed optical path through the tube for flame monitoring.

Inventive Principle:
Principle #1Segmentation

2Temperature

If air cooling is applied to the sensor to reduce heat exposure, then the temperature control is improved, but dust particles settle on the optics reducing light signal

Engineering Contradiction:
Improvesensor operating temperatureVSAvoidlight signal quality
Core Design Contradiction:
TemperatureVSMeasurement precision

Solution Approach 1:

The tube acts as a protective intermediary that prevents dust-laden cooling air from contacting the optical surfaces. The tube creates a sealed optical path that allows cooling airflow outside while keeping the internal optics clean and free from contamination.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The tube functions as a protective shell enclosing the optical path. This shell structure allows thermal management through controlled airflow external to the tube while maintaining a clean, protected internal environment for the optical components.

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If the sensor is positioned at a distance from the window to limit temperature exposure, then the reliability is improved, but the light signal intensity decreases

Engineering Contradiction:
Improvesensor operational reliabilityVSAvoidlight signal intensity
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The tube serves as an optical intermediary that efficiently transmits light signals from the combustion chamber to the distant sensor. This allows the sensor to be positioned at a safe distance for thermal management while the tube maintains strong optical coupling to preserve signal intensity.

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

This configuration protects the sensor from contamination, maintains a permissible operating temperature, and ensures reliable flame observation with clear light signals, enhancing the sensor's service life and performance.

Implementation Method 1

a tube is provided between the window and the sensor, through which optical rays can pass from the window to the sensor

Methodology Applied
Scientific EffectOptical radiation transmission: Light

Implementation Method 2

a tube is provided between the window and the sensor, through which optical rays can pass from the window to the sensor

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4075111B1Heating device comprising arrangement of an optical sensor on a window to the combustion chamber of a
Publication Date: 2024.09.25 VAILLANT GMBH(DE)
  • EP4075111B1 patent drawingFigure 1
  • EP4075111B1 patent drawingFigure 2~3

AI summary

The invention relates to an arrangement of an optical sensor (9) on the outside of a window (8) located in a housing (3) of a combustion chamber (2) of a heating device (1), the window facing the combustion chamber (2). The sensor (9) is arranged at a distance (A) from the window (8), and a tube (11) is provided between the window (8) and the sensor (9), through which optical rays can pass from the window (8) to the sensor (9). The tube (11) rests against the window (8) with an inlet end (16) in a substantially sealing manner, and the sensor (9) is arranged at or in an outlet end (17) of the tube (11). The tube (11) can also be held in or on an air intake line (12) of the heating device (1) by means of a tube holder (15) for cooling purposes.The present invention allows an optical sensor (9) to be attached to a window (8) to a combustion chamber (2) in a manner appropriate to its sensitivity, while simultaneously avoiding contamination of the window (8) and/or sensor (9) and maintaining a permissible temperature range of the sensor (9).