S-Shaped Lattice Webs for Thermoresistive Gas Sensor
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Solution Overview
Problem
Conventional thermoresistive gas sensors face challenges in achieving high measurement sensitivity and mechanical stability while maintaining intrinsically safe operation, especially in areas at risk of explosion, due to high electrical resistance and potential chemical aggression.
Innovation Solution
A thermoresistive gas sensor with a flat lattice structure featuring s-shaped semiconductor lattice webs connected electrically in parallel, made from doped semiconductor materials like silicon, which provides high detection sensitivity and mechanical stability without excessive voltage drop, allowing for intrinsically safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high electrical resistance is used in the heating element, then detection sensitivity is improved, but voltage drop increases causing safety issues in explosive environments
Solution Approach 1:
The heating element is divided into multiple heating sections arranged in parallel, each section contributing to the overall heating function while distributing the electrical load. This segmentation allows the sensor to achieve high detection sensitivity through appropriate resistance values in each section while maintaining lower overall voltage drop for safety in explosive environments.
2Measurement precision
If high temperature is used to increase temperature difference for sensitivity, then detection sensitivity is improved, but service life of heating element deteriorates
Solution Approach 1:
The sensor utilizes the local thermal conductivity differences between the heating element and the duct wall to create the measurement signal, rather than relying on extremely high temperatures. This allows sufficient detection sensitivity to be achieved through optimized thermal coupling and geometry while maintaining temperatures that preserve the service life of the heating element.
3Adaptability or versatility
If chemically aggressive gases are present, then measurement capability is improved, but corrosion of heating filament occurs
Solution Approach 1:
The heating element is constructed from chemically inert materials such as platinum or gold, which form a protective composite structure resistant to corrosion by chemically aggressive gases. This material selection maintains both the measurement capability across different gas types and the long-term reliability by preventing degradation from chemical exposure.
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 parallel connection of s-shaped lattice webs in the gas sensor achieves high detection sensitivity and mechanical stability, enabling safe operation in explosive environments while resisting chemical aggression, with a reduced voltage drop and improved temperature distribution.
Implementation Method 1
A thermoresistive gas sensor with a flat lattice through which a gas can flow with lattice webs, which consist of a semiconductor material with a predetermined type of conductivity... The lattice webs are formed to extend in an s shape in the plane of the lattice and are connected electrically in parallel
Implementation Method 2
A thermoresistive sensor or detector is a measurement sensor with an electrical resistor, of which the value changes reproducibly with the temperature. Such resistors are also referred to as thermistors
Implementation Method 3
When a fluid is flowing around the sensor heat is transported into the fluid, which changes with the speed of the flow
Data Source
AI summary
A thermoresistive gas sensor, e.g. for a flow sensor or a thermal conductivity detector, has a lattice with lattice webs, which consist of a semiconductor material arranged in the plane of the lattice in parallel next to one another, wherein the semiconductor material is formed on a plate-shaped semiconductor substrate that extends over a window-like cutout in the semiconductor substrate and forms the lattice, where the semiconductor layer is doped outside the cutout in areas of two ends of the lattice at least over the width of the lattice until it degenerates and/or bears metallizations, where the semiconductor layer further contains a separation structure insulating the two ends of the lattice from one another, in which the semiconductor material is removed or is not doped, and where the lattice webs extend in an S shape and are connected electrically in parallel to achieve a high measurement sensitivity and mechanical stability.