Gas Analyzer Micro-Flow Half-Spaced Gas Chamber

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Solution Overview

Problem

Current gas analyzers using non-dispersive infrared (NDIR) technology face challenges in achieving accurate and stable measurements at ultra-low scales (0-100 mg/m3) due to issues like moisture interference, complex structures, and high costs, particularly for monitoring SO2, NO, and CO emissions, as existing dual-beam and single-gas chamber designs are prone to drift and instability.

Innovation Solution

A gas analyzer employing a half-spaced gas chamber combined with a micro-flow infrared detection device, featuring a water adjustment system to mitigate moisture interference, and a light switch plate mechanism for alternating light exposure between reference and measurement gas chambers, ensuring accurate and stable measurements by distinguishing between gas and water absorption spectra.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a dual-beam pneumatic infrared sensor with fork-shaped double-tube double-gas-chamber structure is used, then measurement stability is improved, but device complexity and cost increase

Engineering Contradiction:
Improvemeasurement stabilityVSAvoidgas chamber structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The gas chamber is divided into two separate chambers: a reference gas chamber and a measurement gas chamber. This segmentation allows independent optimization of each chamber's function while reducing overall structural complexity compared to fork-shaped double-tube designs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines the reference gas chamber and measurement gas chamber into a single integrated sensor structure with shared components (light source, detectors, optical path), achieving measurement stability through differential measurement while reducing device complexity and cost.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If a beam splitter is used in the infrared light path, then dual-beam measurement is achieved, but signal loss occurs due to infrared light reflection

Engineering Contradiction:
Improvedual-beam measurement capabilityVSAvoidinfrared light signal loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

Instead of using a beam splitter to divide the light path, the patent inverts the approach by using two separate optical paths with independent light sources and detectors. This eliminates the need for beam splitting, avoiding infrared light reflection losses while maintaining dual-beam measurement capability.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent creates a complete copy of the optical path for the reference measurement, including light source, optical components, and detector. This copying approach eliminates signal loss from beam splitting while achieving the same differential measurement function.

Inventive Principle:
Principle #26Copying

3Ease of operation

If photo-pneumatic sensors with leftward and rightward airflow are used, then measurement is enabled, but moisture interference cannot be avoided

Engineering Contradiction:
Improvemeasurement capabilityVSAvoidmoisture interference
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the moisture interference problem from the measurement system by introducing a reference gas chamber that measures only moisture content. This separates the moisture measurement function from the gas concentration measurement, allowing moisture compensation without interfering with the primary measurement.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The reference gas chamber acts as an intermediary that measures moisture content separately. This intermediary measurement allows the system to compensate for moisture effects in the main measurement channel without the moisture directly interfering with the gas concentration detection.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Device complexity

If single-gas-chamber structure is used, then device simplicity is achieved, but measurement drift and poor stability occur

Engineering Contradiction:
Improvegas chamber structure simplicityVSAvoidmeasurement stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The gas chamber is segmented into two functional chambers: reference gas chamber and measurement gas chamber. This segmentation enables differential measurement that compensates for environmental drift while maintaining a simple integrated structure, achieving both simplicity and stability.

Inventive Principle:
Principle #1Segmentation

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

The solution provides enhanced measurement accuracy and stability at ultra-low scales, reducing interference from moisture and environmental factors, while minimizing instrument size and cost, thus meeting stringent environmental monitoring requirements.

Implementation Method 1

infrared absorption characteristics of components such as SO2, NO, CO2, CO and the like in the flue gas is analyzed according to the Lambert-Beer law

Methodology Applied
Scientific EffectInfrared absorption: Absorption (EM radiation)

Implementation Method 2

infrared absorption characteristics of components such as SO2, NO, CO2, CO and the like in the flue gas is analyzed according to the Lambert-Beer law

Methodology Applied
Scientific EffectLambert-Beer law: Absorption (EM radiation)

Implementation Method 3

the defect of which is that photo-pneumatic sensors (microphone sensors) are used, the measured airflow flows leftward and rightward relative to the emission direction of the light source, thus unable to avoid the interference of moisture on the measurement

Methodology Applied
Scientific EffectMoisture interference elimination: Absorption (EM radiation)

Data Source

PatentEP3674689B1Gas analyzer and gas analyzing method
Publication Date: 2023.12.13 CUBIC INSTR (WUHAN) LTD
  • EP3674689B1 patent drawingFigure 1
  • EP3674689B1 patent drawingFigure 2~3
  • EP3674689B1 patent drawingFigure 4~5

AI summary

The present invention provides a gas analyzer and a gas analyzing method, which relates to the gas analysis field and advantageously uses the micro-flow half-spaced gas chamber technology to achieve the measurement of the gas to be measured. The main features include: a reference gas chamber and a measurement gas chamber are disposed in a single cavity, and a micro-flow infrared gas detection device in which the gas flows in the forward or rearward direction, which addresses the issues of large drift and poor measurement stability due to the use of single-gas-chamber and the issues of complicated process and structure due to the use of separate dual-gas-chamber. In addition, a water adjustment device is disposed in the micro-flow infrared gas detection device. By identifying the overlapping phenomenon of the absorption spectrums of the gaseous water and the gas to be measured and by taking advantage of the difference between the infrared absorption spectrums of the gaseous water and the gas to be measured, the water adjustment valve is adjusted to change the velocity variation due to the expansion of the gas in the front and rear gas chambers and the water adjustment buffer gas chamber of the micro-flow infrared gas detection device, such that the detected infrared spectrum is located within the absorption spectrum of the gas to be measured while away from the absorption spectrum of the gaseous water, thus addressing the water interference issue.