Transcutaneous Gas Sensor With High Thermal Conductivity Casing
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Solution Overview
Problem
Current transcutaneous gas sensors face challenges with slow gas permeation through tissue, requiring small measurement chamber volumes and being sensitive to disturbances like leakage and radiation absorption, which complicates accurate and rapid gas concentration measurement, especially in clinical settings involving extracorporeal blood circulation.
Innovation Solution
The development of a sensor with a high thermal conductivity casing, multiple gas-access channels, and a venting channel system to reduce unwanted gas accumulation, combined with a reflective mirror and optical module support for efficient radiation path and gas equilibration, minimizes response time and enhances measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the measurement chamber volume is reduced to achieve fast response time, then the response time is improved, but the optical intensity guiding becomes more difficult and sensitivity to disturbances increases
Solution Approach 1:
The measurement chamber is segmented into multiple smaller chambers (first measurement chamber and second measurement chamber) separated by a partition. This segmentation allows each chamber to have a small volume for fast response while the overall system maintains sufficient optical path length and measurement capability, reducing sensitivity to disturbances in any single chamber.
2Loss of time
If multiple gas-access channels are added to improve gas equilibration, then the response time is improved, but the device complexity increases
Solution Approach 1:
The gas-access channels are segmented and distributed to different measurement chambers (first gas-access channel to first chamber, second gas-access channel to second chamber). This segmentation enables parallel gas equilibration in multiple chambers simultaneously, reducing overall equilibration time while maintaining manageable complexity through modular channel design.
3Measurement precision
If a venting channel system is added to reduce unwanted gas accumulation, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The venting channel system extracts and removes unwanted gases (such as anesthetic gases) from the measurement chambers separately from the sample gas measurement path. This extraction function improves measurement precision by eliminating interfering substances while the venting channels are integrated into the existing chamber structure to minimize additional complexity.
4Loss of time
If the measurement chamber volume is reduced for fast response, then the response time is improved, but the optical path intensity becomes insufficient
Solution Approach 1:
The optical measurement system is segmented into multiple independent measurement chambers, each with its own optical path. This allows the total optical path length to be distributed across multiple small chambers, maintaining sufficient optical intensity in each chamber while the small individual chamber volumes ensure fast response times.
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 sensor achieves rapid and accurate gas concentration measurement with reduced sensitivity to disturbances, providing stable results within acceptable response times without frequent calibrations, and is manufactured using cost-effective and straightforward methods.
Implementation Method 1
Sample gas being present in a measurement chamber can give rise to absorption of measurement radiation and therewith to a measurement signal
Implementation Method 2
The sensor further comprises a mirror that is arranged such that the radiation path involves a reflection at the mirror
Implementation Method 3
at least one gas-access channel enabling sample gas, preferably transcutaneous gas, to migrate from the contact face into the measurement chamber
Implementation Method 4
The casing comprises or entirely consists of a material having a high thermal conductivity. The thermal conductivity preferably exceeds 10 W/m/K
Data Source
AI summary
The invention concerns sensors (1) for detection of gas, in particular sensors for detection of transcutaneous gas such as CO2, and methods for manufacturing a sensor (1). The sensor (1) comprises at least one radiation source (3) for emitting radiation, at least one detector (4) for detection of radiation emitted by the radiation source (3), and at least one measurement chamber (6) for receiving the sample gas. The radiation source (3), the detector (4), and the measurement chamber (6) are arranged such that at least a part of the radiation propagates along a path passing through the measurement chamber (6). The sensor (1) further comprises a casing (7), wherein the radiation source (3), the detector (4), the measurement chamber (6) are arranged. The sensor (1) has a contact face (8) which is directable towards a measuring site and the sensor (1) has at least one gas-access channel (9) enabling gas to migrate from the contact face (8) into the measurement chamber (6). The casing (7) comprises a, preferably metallic, material having a high thermal conductivity, preferably more than 10 W/m/K.