Gas Sensor Element With Isolated Reference Gas Chamber
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Solution Overview
Problem
Existing gas sensors face challenges in maintaining a stable oxygen concentration around the reference electrode, leading to fluctuations in detection accuracy due to external influences and improper oxygen pumping.
Innovation Solution
The sensor element incorporates a reference gas chamber isolated from the outside and measurement-object gas flow portion, with a densely formed electrically conductive portion to block oxygen movement, and optionally includes a dense layer or porous body to reduce oxygen ion conductivity and increase spatial volume, ensuring minimal oxygen exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the reference gas inlet space and reference gas inlet layer are used to allow communication between outside and reference electrode, then oxygen can be supplied to reference electrode, but oxygen concentration around reference electrode decreases due to external influences
Solution Approach 1:
The sensor element is divided into separate isolated chambers: a reference gas chamber containing the reference electrode, a measurement gas chamber, and an oxygen supply chamber. This segmentation prevents external atmosphere from directly contacting the reference electrode while maintaining oxygen supply through controlled pathways, thus preserving oxygen concentration and detection accuracy.
Solution Approach 2:
A dense layer is introduced as an intermediary barrier between the reference gas chamber and the outside environment. This dense layer blocks oxygen diffusion from external sources while allowing controlled oxygen supply from the oxygen supply chamber, preventing oxygen concentration changes caused by external atmospheric influences.
2Quantity of substance
If reference gas adjustment device pumps oxygen into reference electrode area, then oxygen concentration can be maintained, but pumping amount may be too large or too small causing instability
Solution Approach 1:
The oxygen supply chamber is designed to automatically supply oxygen to the reference gas chamber through a dense layer barrier, eliminating the need for active pumping control. The system self-regulates oxygen concentration maintenance without requiring external control mechanisms, avoiding the instability caused by imprecise pumping amounts.
3Reliability
If reference gas chamber is isolated from outside and measurement gas flow portion, then oxygen concentration stability is improved, but device complexity increases
Solution Approach 1:
The reference gas chamber is nested within the sensor element structure, containing the reference electrode and surrounding it with a dense layer barrier. The oxygen supply chamber is integrated into the same element, creating a compact nested configuration that achieves isolation and stability without excessive structural complexity.
Solution Approach 2:
A dense layer with controlled thickness is used as a barrier film between the reference gas chamber and external environment. This thin film structure provides effective oxygen diffusion blocking while maintaining a compact design, balancing isolation requirements with structural simplicity.
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 configuration effectively suppresses changes in oxygen concentration around the reference electrode, enhancing the accuracy and reliability of gas concentration detection by minimizing external interference and oxygen flow.
Implementation Method 1
At least part of the electrically conductive portion is densely formed so as to block movement of oxygen between the reference gas chamber and the outside of the element body via the electrically conductive portion
Implementation Method 2
an element body including an oxygen-ion-conductive solid electrolyte layer
Data Source
AI summary
A sensor element for detecting a specific gas concentration in a measurement-object gas includes: an element body including an oxygen-ion-conductive solid electrolyte layer, and having inside a measurement-object gas flow portion that introduces and flows a measurement-object gas and a reference gas chamber used to store a reference gas that is a reference for detecting a specific gas concentration; a reference electrode disposed in the reference gas chamber; and an electrically conductive portion which includes a reference electrode terminal and a reference electrode lead portion that provides electrical continuity between the reference electrode terminal and the reference electrode. The reference gas chamber is provided inside the sensor element in an isolated form, and at least part of the electrically conductive portion is densely formed so as to block movement of oxygen between the reference gas chamber and the outside of the sensor element via the electrically conductive portion.