MOS Hydrogen Sulfide Detector Humidity Compensation

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Solution Overview

Problem

Metal oxide semiconductor-type hydrogen sulfide gas sensors are susceptible to errors caused by changes in environmental humidity and temperature, leading to inaccurate measurements at ppm levels.

Innovation Solution

Incorporating a relative humidity and temperature measurement system to compensate the hydrogen sulfide gas sensor output using an equation that accounts for environmental conditions, ensuring improved accuracy in hydrogen sulfide gas concentration measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If metal oxide semiconductor sensors are used for hydrogen sulfide detection, then the sensor can operate in wide ranging temperatures and dry conditions with long life, but the sensor becomes susceptible to errors caused by changes in environmental humidity and temperature

Engineering Contradiction:
Improvesensor lifeVSAvoidmeasurement accuracy
Core Design Contradiction:
Duration of action of stationary objectVSMeasurement precision

Solution Approach 1:

The patent incorporates humidity and temperature sensors that continuously monitor environmental conditions and feed this data back to a processor. The processor uses this feedback to dynamically adjust and compensate the hydrogen sulfide sensor readings, eliminating measurement errors caused by environmental variations while preserving the sensor's long operational life

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the operational parameters by introducing separate humidity and temperature sensing capabilities. By measuring these environmental parameters independently and using them to compensate the main sensor output, the system maintains measurement accuracy across varying environmental conditions while retaining the robustness and longevity of metal oxide semiconductor sensors

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If sensor response times and stability are improved to detect low concentrations, then acceptable exposure levels can be decreased, but environmental condition variations become dominant in determining sensor precision

Engineering Contradiction:
Improvedetection precisionVSAvoidenvironmental interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces humidity and temperature sensors as intermediary devices that mediate between the environmental conditions and the hydrogen sulfide sensor. These intermediaries measure the environmental factors and enable compensation calculations, effectively isolating the main sensor from environmental interference and maintaining high detection precision

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

By implementing a feedback loop where environmental sensor data continuously adjusts the hydrogen sulfide sensor readings, the system maintains high detection precision even at low concentration levels. The feedback mechanism counteracts environmental interference in real-time, allowing for decreased acceptable exposure levels with confidence in measurement accuracy

Inventive Principle:
Principle #23Feedback

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 accuracy in hydrogen sulfide gas detection by effectively compensating for humidity and temperature variations, leading to improved precision and reliability in industrial settings.

Implementation Method 1

When hydrogen sulfide gas comes into contact with the gas sensitive material, there is a measurable change in the electrical conductivity

Methodology Applied
Scientific EffectElectrical conductivity change: Conduction (electrical)

Implementation Method 2

a hydrogen sulfide sensor is constructed as a sandwich of a platinum heater element

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3004856B1Hydrogen sulfide gas detector with humidity and temperature compensation
Publication Date: 2021.06.30 ROSEMOUNT INC
  • EP3004856B1 patent drawingFigure 1
  • EP3004856B1 patent drawingFigure 2
  • EP3004856B1 patent drawingFigure 3

AI summary

A hydrogen sulfide gas detector (10) is provided. The detector (10) includes a metal oxide semiconductor-based hydrogen sulfide gas sensor (30) having an electrical characteristic that varies with hydrogen sulfide gas concentration. Measurement circuitry (28) is coupled to the metal oxide semiconductor-based hydrogen sulfide gas sensor (30) to measure the electrical characteristic. A controller (22) is coupled to the measurement circuitry (28) and is configured to receive an indication of the electrical characteristic of the hydrogen sulfide gas sensor (30) as well as an indication of ambient humidity. The controller (22) is configured to provide a compensated hydrogen sulfide gas concentration output based on the indication of the electrical characteristic of the hydrogen sulfide gas sensor (30), an indication of ambient temperature, and the indication of ambient humidity.