Vented Protective Tube for Gas-Tight Temperature Sensing
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Solution Overview
Problem
Existing protective tubes for temperature sensors in double-walled pipes or containers face challenges in maintaining a gas-tight seal while allowing thermal coupling, especially in applications involving low-temperature gases or high-temperature media, where convection and condensation can occur, leading to reduced measurement accuracy and potential chemical reactions.
Innovation Solution
A protective tube design with a ventilation device that can be set to be gas-permeable for evacuation or purging, and a dual connection system to ensure a gas-tight seal at both the outer and inner walls, combined with a thin-walled or elastically deformable section to reduce heat conduction and accommodate misalignments, allowing for reliable temperature measurement without medium leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the protective tube is made thick-walled to ensure mechanical strength and protection, then the protective capability is improved, but the thermal coupling between the temperature sensor and the medium deteriorates
Solution Approach 1:
The protective tube employs different wall thicknesses in different sections: the first section (outer section) has a greater wall thickness for mechanical strength, while the second section (inner section) has a smaller wall thickness for better thermal coupling. This local differentiation resolves the contradiction by optimizing each section for its specific function.
2Measurement precision
If the protective tube is made of material with high thermal conductivity to improve thermal coupling, then the temperature measurement responsiveness is improved, but the heat loss along the protective tube increases
Solution Approach 1:
The protective tube uses materials with different thermal conductivities in different sections: the first section uses a material with higher thermal conductivity for mechanical strength and protection, while the second section uses a material with lower thermal conductivity to minimize heat loss. This local differentiation resolves the contradiction by optimizing each section for its specific function.
3Device complexity
If the connection part is arranged flush with the proximal end to simplify the structure, then the device complexity is reduced, but the gas-tight sealing capability deteriorates
Solution Approach 1:
The connection part is arranged to protrude from the proximal end of the protective tube body, utilizing the longitudinal dimension to provide space for sealing structures. This dimensional arrangement allows the inclusion of sealing elements without significantly increasing overall structural complexity, thus resolving the contradiction between simplicity and sealing capability.
4Stability of the object's composition
If the protective tube body is made rigid to maintain structural stability, then the structural stability is improved, but the ability to accommodate misalignments between openings deteriorates
Solution Approach 1:
The protective tube body includes a flexible section with reduced wall thickness that can elastically deform to accommodate misalignments between the first and second openings. This flexible section maintains overall structural stability while providing the necessary adaptability, resolving the contradiction between rigidity and flexibility.
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 solution ensures accurate temperature measurement by preventing medium leakage and reducing convection and condensation, while maintaining thermal coupling and operational safety, even in challenging environments.
Implementation Method 1
the temperature sensor is thermally coupled to the measuring environment by the protective tube, so that temperature measurement is possible
Implementation Method 2
a ventilation device which is adapted to open a connection line between an intermediate space between an outer wall section and an inner wall section of the double-walled pipe or the double-walled container and the duct of the protective tube in a first setting so as to be permeable to gas
Data Source
AI summary
The present disclosure relates to a protective tube with a protective tube body, a duct for inserting a measuring insert, a first connection part, which is designed for the direct or indirect closure of a first opening in an outer wall section of a double-walled pipe or a double-walled container, a second connection part, which is designed for the direct or indirect closure of a second opening in an inner wall section of the double-walled pipe or of the double-walled container, a ventilation device which is designed to release a connection line between an intermediate space between the outer wall section and the inner wall section and the duct in a first setting permeable to gas, and/or an access device, which is designed to release a connection line between an external environment and the duct in a first setting permeable to gas and to close it in a second setting, impermeable to gas.