Catalytic Gas Sensor with Segmented Insulating Supports
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Solution Overview
Problem
Existing gas sensors with catalytic measuring elements embedded in heat-insulating covers face reduced gas diffusion and sensitivity, particularly for high-boiling gases, due to the additional diffusion barrier, resulting in poorer response times and sensitivity compared to unsupported Pellistors.
Innovation Solution
A gas sensor design featuring a sensor housing with a gas-permeable opening and disk-shaped support elements made of heat-insulating, temperature-resistant materials, allowing for improved gas exchange and mechanical protection of the catalytic measuring elements, which are positioned between the support elements to enhance diffusion and reduce temperature sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the catalytic measuring element is embedded directly in a gas-permeable heat-insulating cover, then heat release is reduced and energy consumption is reduced, but gas diffusion is hindered and response time increases
Solution Approach 1:
The cover is segmented into a first cover portion and a second cover portion, with the catalytic measuring element arranged between them. This segmentation allows the element to be mechanically protected and thermally insulated while maintaining direct gas access through the combustion chamber opening, resolving the contradiction between heat insulation and gas diffusion.
2Stability of the object's composition
If the catalytic measuring element is embedded in a heat-insulating cover, then temperature stability is improved, but gas accessibility to the measuring element is reduced
Solution Approach 1:
The first and second cover portions act as intermediary heat-insulating structures that protect the catalytic measuring element thermally while allowing gas to reach it through the combustion chamber. The measuring element is positioned between these portions, which mediate between the need for thermal stability and gas accessibility.
3Productivity
If the catalytic measuring element is unsupported, then gas diffusion is improved, but mechanical protection and heat insulation are reduced
Solution Approach 1:
The cover is divided into two portions with the measuring element between them, providing mechanical support and heat insulation without completely enclosing the element. This segmentation maintains gas diffusion pathways while providing the necessary mechanical protection.
Solution Approach 2:
The sensor housing combines different materials with complementary properties: the sensor housing provides structural strength, the cover portions provide heat insulation, and the open combustion chamber structure provides gas permeability. This composite structure achieves both mechanical protection and gas diffusion efficiency.
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 improved gas exchange results in faster response times and increased sensitivity for gases, with a methane-to-nonane sensitivity ratio enhanced from 6-8 to 4-5, and better signal-to-noise ratios, while maintaining shock resistance and reduced temperature sensitivity.
Implementation Method 1
gas sensor with at least one catalytic measuring element... whose concentration can be measured by controlled combustion
Implementation Method 2
Two disk-shaped support elements are provided made of a heat-insulating and temperature-resistant material
Implementation Method 3
at least one gas-permeable housing opening for a gas exchange between the environment and the combustion chamber
Data Source
AI summary
A gas sensor has shock resistance and temperature resistance attributes. The gas sensor includes at least one catalytic measuring element (3), which is arranged in a sensor housing (1) forming a combustion chamber (2). The sensor housing (1) has at least one gas-permeable housing opening (4) for the gas exchange between the environment and the combustion chamber (2). The catalytic measuring element (3) is arranged between at least two disk-shaped support elements (5) made of a heat-insulating and temperature-resistant material.