TDLS Gas Sensor Thermal Isolation for Incubator Sterilization
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Solution Overview
Problem
Current CO2 and humidity sensors in incubators fail to withstand high sterilization temperatures, requiring manual disassembly and leading to imprecise measurements due to temperature limitations and back reflections, which disrupt the measurement process.
Innovation Solution
A TDLS gas sensor design with a window angled to the laser beam axis, a thermally conductive material block for heat dissipation, and a heating device to prevent condensation, allowing the sensor to remain installed during sterilization and enabling precise CO2 and humidity measurements without back reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current CO2 and humidity sensors are placed inside the incubator for continuous measurement, then measurement capability is maintained, but the sensors cannot withstand sterilization temperatures up to 200°C and must be dismantled
Solution Approach 1:
The sensor system is divided into two separate modules: a sterilizable measurement chamber that remains in the incubator and an electronic control unit that remains outside. The measurement chamber can withstand autoclaving temperatures while the electronics are protected from thermal damage, eliminating the need for disassembly during sterilization cycles.
Solution Approach 2:
A sealed window or transparent barrier is introduced between the measurement chamber and the external electronics. This intermediary allows optical or electromagnetic signals to pass through while providing thermal isolation, enabling the sensors to remain installed during sterilization without exposing sensitive electronic components to high temperatures.
2Temperature
If NDIR sensors are used for CO2 measurement inside the incubator, then the sensors can operate at high temperatures, but measurement precision is reduced due to thermal conductivity limitations and structural constraints
Solution Approach 1:
The patent replaces traditional thermal conductivity-based NDIR sensors with optical detection methods that use a laser source and photodetector. This substitution allows for precise CO2 measurements while maintaining the ability to withstand high sterilization temperatures, as the optical components are sealed in a sterilizable chamber rather than being directly exposed to thermal stress.
3Productivity
If sensors remain installed in the incubator during sterilization, then operational continuity is maintained, but back reflections from hot surfaces disrupt measurement accuracy
Solution Approach 1:
The measurement chamber is designed with pre-cooled surfaces and thermal insulation barriers that prevent excessive heat accumulation during sterilization. By maintaining the internal measurement environment at a lower temperature than the external sterilization chamber, back reflections and thermal interference are minimized, preserving measurement accuracy throughout the sterilization cycle.
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
Enables reliable and precise simultaneous measurement of CO2 and humidity levels within incubators during both normal operation and sterilization cycles, preventing sensor disassembly and maintaining measurement accuracy.
Implementation Method 1
The TDLS measurement principle is well known and is a highly selective and versatile technique to measure many traces of atmospheric substances with a detection sensitivity in the ppb range. Here, the concentration of the gas or gas component to be examined is determined from a measured absorption.
Implementation Method 2
with at least one reflector that directs the laser light emitted by the laser diode onto the detector
Implementation Method 3
with a heating device for the window, which prevents condensation on the window by heating
Implementation Method 4
a thermally conductive material block for heat dissipation
Data Source
Figure 1
Figure 2~3
AI summary
The TDLS gas sensor (1) has an absorption pick-up unit (3) that is arranged in an inner side of interior chamber (18). The to-be-measured gas is circulated in the interior chamber of incubator. A reflector is provided to guide the laser beam emitted by a laser diode to a detector. A window (9) is provided to separate a measuring pick-up unit (2) and the absorption pick-up unit. An optronic component in the measuring pick-up unit is thermally uncoupled from the absorption pick-up unit. An independent claim is included for process for measuring moisture and carbon dioxide in interior chamber of incubator/climate chamber.