Gas Sensor Tapered Passage Thermal Isolation
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Solution Overview
Problem
Existing gas sensors face accuracy issues due to temperature limitations, where the light source and detector are exposed to high temperatures, leading to decreased detection accuracy, especially when mounted in constant-temperature apparatuses undergoing sterilization.
Innovation Solution
A gas sensor design featuring a gas detection unit with a light source and detector isolated from direct exposure to high temperatures through a gas passage with a tapered shape and partition member, allowing gas to flow while maintaining temperature isolation of the light source and detector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the light source and detector are exposed to the gas subject to detection for direct measurement, then the detection accuracy is improved, but the temperature withstand capability deteriorates when the gas temperature exceeds 100°C
Solution Approach 1:
The gas passage is divided into a first passage for light transmission and a second passage for gas flow, physically separating the light path from the hot gas environment. This segmentation allows the light source and detector to remain in a cooler zone while still enabling gas detection through the optical path.
Solution Approach 2:
The first passage acts as an intermediary medium that transmits light from the light source to the detector while isolating these components from direct exposure to high-temperature gas. The optical path serves as a mediator that enables detection without thermal contact.
2Productivity
If the gas passage has a large cross-sectional area to allow sufficient gas flow, then the gas circulation efficiency is improved, but the temperature isolation effectiveness deteriorates
Solution Approach 1:
The gas passage features different cross-sectional areas at different locations: a larger cross-sectional area in the gas flow region to ensure sufficient gas circulation, and a smaller cross-sectional area in the light transmission region to maintain effective temperature isolation. This local variation in geometry optimizes both gas flow and thermal protection.
Solution Approach 2:
The gas passage has an asymmetric cross-sectional profile along its length, with the first passage (light path) having a smaller cross-section than the second passage (gas flow path). This asymmetric design allows the system to simultaneously achieve good gas circulation in the flow path and effective thermal isolation in the light path region.
3Measurement precision
If the light passage length is increased to improve light absorption measurement, then the detection sensitivity is improved, but the temperature exposure time deteriorates
Solution Approach 1:
The optical path is segmented from the hot gas environment by creating a dedicated first passage that transmits light through a cooler region. This allows the light to travel a sufficient distance for effective absorption measurement while remaining thermally isolated from the high-temperature gas in the second passage.
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 design effectively prevents damage to the light source and detector from high temperatures, maintaining detection accuracy and enabling safe sterilization processes without removing the gas sensor.
Implementation Method 1
a detector that receives the light and detects the gas subject to detection based on absorption of the light by the gas subject to detection
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A gas sensor 100 is provided with: a gas detection section 101 having a light source 102 and a detector; and a gas passage section 130, which has a first end section 144, a second end section 146, and a hollow section 148, said first end section 144 being disposed on the gas detection section 101 side, and said second end section 146 being disposed on the gas space side. The hollow section 148 has a shape wherein a flow passage cross-sectional area N is reduced toward the first end section 144 side from the second end section 146 side. The gas passage section 130 has: a member 152 that partitions the hollow section 148 into at least a first region 148a and a second region 148b; a gas inflow port 154 that connects the gas space and the first region 148a to each other; and a gas outflow port 156 that connects the second region 148b and the gas space to each other. A gas to be detected flows into the hollow section 148 from the gas inflow port 154, flows in the first region 148a, and reaches the gas detection section 101, and the gas in the gas detection section 101 flows in the second region 148b, and flows out to the gas space from the gas outflow port 156.