Solid Electrolyte Sensor Assembly for Formaldehyde Detection

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Solution Overview

Problem

Current formaldehyde detectors suffer from cross-sensitivity to carbon monoxide, leading to false alarms and ineffective detection due to the presence of CO in higher concentrations, and high-quality detectors are often prohibitively expensive.

Innovation Solution

Employing two solid electrolyte sensors operating under different conditions, such as varying bias potentials and filters, to isolate and detect formaldehyde while canceling out noise and improving resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single sensor with catalyst electrode is used to detect formaldehyde, then the detection threshold can be set low for safety, but cross-sensitivity to carbon monoxide causes false alarms

Engineering Contradiction:
Improvedetection accuracyVSAvoidcross-sensitivity to CO
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system divides the detection function into two separate sensors: a first sensor detects both formaldehyde and carbon monoxide, while a second sensor detects only carbon monoxide. By segmenting the detection roles, the system can differentiate between signals from target gas and interferent gas, eliminating false alarms while maintaining low detection thresholds.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second sensor acts as an intermediary that measures the carbon monoxide component separately. This intermediary measurement allows the system to subtract the CO contribution from the total signal, isolating the formaldehyde signal and removing the harmful cross-sensitivity effect.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If high-quality sensors with high selectivity are used, then cross-sensitivity is reduced, but the cost becomes prohibitively expensive for domestic use

Engineering Contradiction:
Improvecross-sensitivityVSAvoidcost
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The system uses two relatively inexpensive solid electrolyte sensor elements instead of one high-cost selective sensor. By employing cheaper components in a multi-sensor configuration, the system achieves high selectivity through signal processing rather than relying on expensive selective materials, making the solution economically viable for widespread domestic deployment.

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

3Object-affected harmful factors

If multiple sensors are used to improve selectivity, then cross-sensitivity is reduced, but device complexity increases

Engineering Contradiction:
Improvecross-sensitivityVSAvoidsensor assembly complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The system merges the functionality of multiple sensors into a single integrated sensor assembly. The first and second solid electrolyte sensor elements are combined in one housing with shared components, allowing the system to achieve improved selectivity through multiple sensing elements while minimizing the increase in overall device complexity through consolidation.

Inventive Principle:
Principle #5Merging (Combining)

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 allows for accurate detection of formaldehyde at lower concentrations without cross-sensitivity to CO, providing a cost-effective solution for widespread domestic use with enhanced detection resolution.

Implementation Method 1

an electrode of the sensor can comprise a catalyst that can catalyze the reaction of both a target gas and an interferent gas

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 2

electrode of the sensor can comprise a catalyst that can catalyze the reaction of both a target gas and an interferent gas

Methodology Applied
Scientific EffectElectrochemical reaction:

Data Source

PatentEP3701255B1Systems and methods for using a plurality of solid electrolyte sensors for a selective, low resolution formaldehyde detector
Publication Date: 2024.12.11 HONEYWELL INTERNATIONAL INC
  • EP3701255B1 patent drawingFigure 1~2
  • EP3701255B1 patent drawingFigure 3A
  • EP3701255B1 patent drawingFigure 3B

AI summary

Systems and methods for determining the concentration of a second target gas while in the presence of a first target gas. A method may comprise operating a first sensor (202, 302) under a first operating condition, wherein the first sensor (202, 302) is part of a sensor assembly (200); operating a second sensor (204, 304) under a second operating condition, wherein the second sensor (204, 304) is part of the sensor assembly (200), and wherein the second operating condition is different from the first operating condition; detecting at least one target gas by the first sensor (202, 302); detecting at least one target gas by the second sensor (204, 304); processing a signal output from the first sensor (202, 302) with a signal output from the second sensor (204, 304); and determining a concentration of at least one of the first target gas and second target gas based on the processed output signals.