Gas Sensor Insulating Ceramic Mount for Sealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing gas sensors face issues with sealing deterioration due to thermal shock and water vapor permeability degradation, particularly when metal materials are used in contact with membrane members, leading to humidity-influenced output and reduced accuracy in detecting combustible gases.
Innovation Solution
The gas sensor employs insulating ceramic or resin materials for the first installation part in contact with the membrane member, ensuring improved sealing and preventing metal ion contamination, while using a membrane permeable to water vapor but not the target gas, and incorporates a measurement target gas oxidation catalyst to maintain concentration differences between inner spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal cap is used in contact with the membrane member, then the structural strength is improved, but the water vapor permeability of the membrane member deteriorates due to metal ion contamination
Solution Approach 1:
An insulating adhesive layer is introduced as an intermediary between the metal cap and the membrane member. This adhesive layer prevents direct contact between metal ions and the membrane, thereby maintaining water vapor permeability while still providing structural support through the metal cap assembly.
Solution Approach 2:
The patent uses a non-metallic cap material (such as resin or ceramic) that is less expensive and does not cause membrane degradation. While metal caps provide superior strength, the non-metallic alternative accepts slight reduction in structural strength to preserve the critical function of the membrane.
2Ease of manufacture
If the mount base and cap are made of different materials with large thermal expansion coefficient difference, then the ease of manufacture is improved, but the sealing reliability deteriorates due to thermal shock
Solution Approach 1:
The patent selects materials for the mount base and cap whose thermal expansion coefficients are within a specific range of each other. This parameter matching ensures that both components expand and contract at similar rates during temperature changes, preventing seal failure while still allowing the use of different materials for manufacturing advantages.
3Reliability
If the first installation part is made of insulating ceramic or resin material, then the sealing reliability is improved, but the structural strength may be reduced
Solution Approach 1:
The patent employs composite construction where insulating ceramic or resin materials are combined with metal components. The insulating material provides sealing reliability by preventing membrane contamination, while the metal parts provide structural strength. The insulating adhesive bonds these dissimilar materials into a unified assembly that achieves both objectives.
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 enhances the sealing of the inner space, maintains water vapor permeability, and suppresses output deterioration, especially at high target gas concentrations, thereby improving the accuracy and reliability of gas detection.
Implementation Method 1
a membrane member arranged to cover the first gas introduction hole and having permeability to water vapor and substantially no permeability to the measurement target gas
Implementation Method 2
incorporates a measurement target gas oxidation catalyst to maintain concentration differences between inner spaces
Data Source
AI summary
Disclosed is a gas sensor for detecting a measurement target gas in a measurement gas atmosphere, including: a first sensor element; a first installation part defining a first inner space in which the first sensor element is installed; and a casing accommodating therein the first installation part. The casing has an opening formed to introduce the measurement target gas into an inside of the casing. The first installation part has: a first gas introduction hole formed to provide communication between the first inner space and the inside of the casing; and a membrane member arranged to cover the first gas introduction hole and having permeability to water vapor and substantially no permeability to the measurement target gas. At least a portion of the first installation part in contact with the membrane member is made of insulating ceramic material or resin material.