Gas Density Sensor Sequencing for Multicomponent Mixture Control

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Solution Overview

Problem

Current methods for measuring gas mixture composition, especially those with more than two components, are hindered by high costs, maintenance requirements, safety concerns, and long response times, and are limited to binary gas mixtures, making them unsuitable for applications requiring efficient and accurate analysis of multicomponent gas mixtures.

Innovation Solution

A system utilizing gas density sensors, in conjunction with pressure and temperature measurements, to calculate the molecular weight of gas mixtures, allowing for the accurate determination of gas composition in mixtures with two, three, or more components, using a series of gas density sensors and a processor to calculate the relative proportions of components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If infrared or laser measurement techniques or gas chromatography are used to measure gas composition of multicomponent mixtures, then measurement precision is improved, but device complexity and cost increase significantly

Engineering Contradiction:
Improvegas composition measurement precisionVSAvoidequipment complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the measurement task by using multiple thermal conductivity sensors, each tuned to detect specific gas components. Instead of using a single complex instrument, the system divides the analysis into multiple simpler measurement channels that can be processed independently and combined to determine overall composition.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces complex optical systems (infrared, laser) or sophisticated sampling systems (gas chromatography with pumps) with simpler thermal conductivity-based sensing. This substitution uses fundamental thermal properties of gases rather than complex optical paths or mechanical sampling mechanisms, thereby reducing device complexity while maintaining measurement capability.

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

2Measurement precision

If pump and sampling system are used to obtain gas samples for analysis, then measurement capability is improved, but response time increases

Engineering Contradiction:
Improvegas composition measurement capabilityVSAvoidresponse time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts the essential measurement function from complex sampling systems. By using thermal conductivity sensors that can operate directly in the gas stream or with minimal sampling, it removes the need for bulky pump and sampling infrastructure, thereby achieving fast response times while maintaining measurement capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The measurement system is designed to be self-sufficient without requiring external pumping or complex sample preparation. The thermal conductivity sensors can directly sense the gas composition in situ, making the system self-service capable and eliminating time-consuming sample transport and preparation steps.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If various technologies are combined into one analysis unit to measure concentration of each component, then measurement precision is improved, but device complexity and maintenance requirements increase

Engineering Contradiction:
Improvecomponent concentration measurement precisionVSAvoidanalysis unit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent creates a universal measurement platform based on thermal conductivity sensing that can detect multiple gas components simultaneously. Rather than combining specialized instruments for each component, a single multi-functional sensor system handles diverse gas analysis needs, reducing overall system complexity while maintaining comprehensive measurement precision.

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

4Measurement precision

If expensive equipment like infrared or laser measurement techniques are used, then measurement precision is improved, but cost increases

Engineering Contradiction:
Improvegas composition measurement precisionVSAvoidequipment cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent employs relatively inexpensive thermal conductivity sensors instead of expensive infrared or laser equipment. These simpler sensors can be manufactured at lower cost and replaced more easily if needed, providing a cost-effective alternative that maintains adequate measurement precision for industrial gas composition analysis.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 provides a cost-effective, reliable, and efficient method for measuring gas composition in multicomponent mixtures, offering improved accuracy and reduced maintenance needs compared to existing technologies, while enabling real-time monitoring and control of gas mixtures.

Implementation Method 1

Gas density sensors are used to measure composition of binary gas mixture

Methodology Applied
Scientific EffectDensity measurement:

Implementation Method 2

A thermal conductivity based sensor can be used as a binary gas mixture analyzer. For example, because hydrogen has a larger thermal conductivity than nitrogen, a thermal conductivity analyzer can be used to measure the composition of nitrogen-hydrogen gas mixture

Methodology Applied
Scientific EffectThermal conductivity: Conduction (thermal)

Implementation Method 3

Infrared or laser measurement techniques, or gas chromatography, can be used to measure gas composition of gas mixture that contains more than two components

Methodology Applied
Scientific EffectGas chromatography: Chromatography

Data Source

PatentEP3611490B1Method and apparatus for using a gas density sensor to measure and control gas mixture composition
Publication Date: 2021.04.07 AIR PROD & CHEM INC
  • EP3611490B1 patent drawingFigure 1
  • EP3611490B1 patent drawingFigure 2

AI summary

An apparatus for measuring the composition of a gas mixture containing known components, including a first gas density sensor configured and arranged to measure the density of a first mixture made by combining a gaseous first component and a gaseous second component; a second gas density sensor configured and arranged to measure the density of a second mixture made by combining the first mixture with a gaseous third component; and a processor programmed to determined based on data from the first gas density sensor the relative compositions of the first component and the second component in the first mixture, and to determine based on the data from the second gas density sensor the relative compositions of the first mixture and the third component in the second mixture, and thus to determine the relative compositions of the first component, the second component, and the third component in the second mixture.