Gas Analyzer Optical-Path Folding for Stable Concentration Measurement

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Solution Overview

Problem

Conventional gas analyzers face challenges in precisely measuring gas concentrations due to fluctuations in light intensity and thermal noise, leading to measurement errors and reduced precision.

Innovation Solution

The gas analyzer employs a configuration with multiple reflecting mirrors inside and outside the cell, adjusted for specific wavelengths to reduce intensity differences, and integrates light signals over multiple flashes to stabilize measurements, using a flash lamp for precise concentration determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional spectrum analyzation is used for gas concentration measurement, then the measurement can be performed, but measurement precision is reduced due to light intensity fluctuations and thermal noise

Engineering Contradiction:
Improvegas concentration measurement precisionVSAvoidmeasurement stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent employs periodic flashing of the light source at controlled intervals, with the light-receiving element exposed to light for specific durations (e.g., 1/100 to 1/1000 of the flash period). By performing multiple flashes and integrating the received light signals over several periods, the system averages out random thermal noise and stabilizes measurements, thereby improving both precision and reliability of gas concentration measurements

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent implements continuous integration of light signals over multiple flash periods, accumulating useful signal information while suppressing random noise through temporal averaging. This continuous integration process maintains measurement stability by consistently applying the same integration window across multiple periodic cycles, ensuring reliable and precise concentration readings

Inventive Principle:
Principle #20Continuity of useful action

2Measurement precision

If multiple reflecting mirrors are added to reduce intensity variations, then measurement precision improves, but device complexity increases

Engineering Contradiction:
Improveintensity variation controlVSAvoidoptical path complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The reflecting mirrors in the optical path serve multiple functions: they extend the effective light path length within the measurement cell, they redirect light to ensure proper illumination of the light-receiving element, and they help distribute light intensity more evenly across the detection area. By making the mirrors multi-functional, the patent improves measurement precision without proportionally increasing device complexity

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

Solution Approach 2:

The patent uses reflecting mirrors to fold the optical path, effectively increasing the light travel distance through the gas sample without increasing the physical dimensions of the measurement cell. This dimensional manipulation allows precise control of light intensity and path length while maintaining a compact device structure, thereby improving precision without excessive complexity increase

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 approach enhances measurement precision by minimizing intensity variations and thermal noise, improving signal-to-noise ratio and reducing measurement errors, thereby providing stable and accurate gas concentration readings.

Implementation Method 1

a plurality of reflecting mirrors 12 may be disposed inside the cell 10. in a reflection area of at least one reflecting mirror 12, a reflectance in at least two wavelengths may be lower than an average reflectance

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

The light-receiving element may receive a radiation spectrum of light that has passed through the cell. The light-receiving element may output a received-light signal

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 3

The light source unit may be a flash lamp

Methodology Applied
Scientific EffectLuminescence: Luminescence

Implementation Method 4

an exhaust gas analyzer based on ultraviolet absorption spectroscopy

Methodology Applied
Scientific EffectAbsorption Spectroscopy: Absorption Spectroscopy

Data Source

PatentEP4160186B1Gas analyzer
Publication Date: 2025.10.15 FUJI ELECTRIC CO LTD
  • EP4160186B1 patent drawingFigure 1
  • EP4160186B1 patent drawingFigure 2
  • EP4160186B1 patent drawingFigure 3

AI summary

A gas analyzer configured to measure a concentration of a measurement target component contained in a gas sample includes: a light source unit for emitting light including an absorption wavelength of the measurement target component; a cell for encapsulating the gas sample; a light-receiving element for obtaining a radiation spectrum of the light that has passed through the cell; a signal processing circuit for processing a received-light signal of the light-receiving element, and measuring a concentration of the measurement target component; and an adjustment unit which is arranged between a light path from the light source unit to the light-receiving element, and for adjusting a characteristic of the radiation spectrum of the light for every wavelength.