Zirconia Sensor Resistance Detection Without Span Gas

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Solution Overview

Problem

The existing methods for measuring the resistance of zirconia sensors in oxygen concentration meters require expensive span and zero gases, reducing convenience and efficiency.

Innovation Solution

An oxygen concentration meter and detection system that includes a zirconia sensor, a parallel resistor, a constant-current circuit, and detection sections to measure resistance and oxygen concentration without the need for standard gases, allowing for the detection of sensor deterioration and abnormality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If span gas and zero gas are used to measure zirconia sensor resistance, then measurement accuracy is improved, but cost increases and convenience decreases

Engineering Contradiction:

Improveresistance measurement accuracyVSAvoidconvenience of resistance measurement

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent extracts the resistance measurement function from the oxygen concentration measurement process. By using a constant-current circuit to apply a known current and measuring the resulting voltage across the zirconia sensor, the resistance can be calculated using Ohm's law (R=V/I) without requiring span gas and zero gas. This separates the resistance measurement from the calibration process that previously required expensive standard gases.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The zirconia sensor serves dual functions: it measures oxygen concentration through electromotive force generation and allows resistance measurement through voltage measurement under constant current. This multi-functionality eliminates the need for separate calibration gases, as the same sensor structure and electrical connections are used for both measurement purposes.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If span gas and zero gas are used for resistance measurement, then sensor deterioration detection is improved, but cost increases

Engineering Contradiction:

Improvesensor deterioration detectionVSAvoidconsumption of expensive standard gases

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts the sensor health monitoring function from the calibration process that consumed span gas and zero gas. By continuously or periodically measuring resistance through voltage measurement under constant current, the system can detect sensor deterioration without consuming any standard gases, thereby improving reliability while eliminating substance consumption.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The zirconia sensor monitors its own health status by measuring its electrical resistance. The sensor's inherent electrical properties allow it to self-diagnose deterioration conditions without requiring external calibration gases or additional monitoring components, making the system self-sufficient for reliability monitoring.

Inventive Principle:

Principle #25Self-service

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 solution increases the convenience of resistance measurement, reduces costs by eliminating the need for expensive standard gases, and enables effective detection of zirconia sensor deterioration and breakage, thereby improving the monitoring and maintenance of oxygen concentration meters.

Implementation Method 1

stabilized zirconia generates electromotive force in accordance with an oxygen concentration difference. Specifically, introducing gases having different oxygen concentrations to one face and the other face of a partition formed of stabilized zirconia generates electromotive force in accordance with an oxygen concentration difference

Methodology Applied

Scientific EffectElectromotive force generation: Nernst Effect

Implementation Method 2

a constant-current circuit that is connected in parallel to the zirconia sensor and the resistor, and that supplies an electric current

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

a resistance detection section configured to detect a resistance of the zirconia sensor, based on a voltage of the zirconia sensor in accordance with the supplied electric current

Methodology Applied

Scientific EffectOhm's law: Ohm's Law

Data Source

PatentUS11802846B2Oxygen concentration meter, oxygen concentration detection system, and method of detecting resistance of zirconia sensor

Publication Date: 2023.10.31 YOKOGAWA ELECTRIC CORP

AI summary

An oxygen concentration meter includes a zirconia sensor, a resistor, a constant-current circuit, a resistance detection section, and an oxygen concentration detection section. The resistor is connected in parallel to the zirconia sensor. The constant-current circuit is connected in parallel to the zirconia sensor and the resistor, and supplies an electric current. The resistance detection section detects the resistance of the zirconia sensor on the basis of the voltage of the zirconia sensor in accordance with the supplied electric current. The oxygen concentration detection section detects the oxygen concentration of gas to be measured that is supplied to the zirconia sensor, on the basis of the voltage of the zirconia sensor resulting from an oxygen concentration difference between the gas to be measured and reference gas.