Protruding Temperature Sensor Tip for Faster Process Measurement
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Solution Overview
Problem
Conventional temperature sensors in industrial process plants face delays in temperature measurement due to the thermal resistance of solid thermowells, leading to longer response times and reduced accuracy.
Innovation Solution
A temperature sensor design featuring a support tube with distal and proximal openings, allowing a sensing element to protrude beyond the thermowell, combined with vacuum brazed solder joints for secure and reliable connections, ensuring direct contact with the process medium and enhanced measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid thermowell is used to protect the sensing element, then the sensing element is protected from damage and impairment, but the thermal resistance increases leading to longer response time
Solution Approach 1:
The patent extracts the sensing element from the thermowell by providing an outlet opening at the distal end of the thermowell, allowing the sensing element to protrude beyond the thermowell and come into direct contact with the process medium. This extraction reduces the thermal resistance while maintaining protection through the brazed connection at the fastening areas.
Solution Approach 2:
The sensing element is nested within the thermowell through the channel, with the measuring tip extending through the outlet opening. The support tube provides structural support while allowing thermal contact, creating a nested configuration that balances protection and thermal responsiveness.
2Loss of time
If the sensing element protrudes beyond the thermowell to reduce thermal resistance, then response time is reduced, but the sensing element becomes vulnerable to damage from strongly flowing process media
Solution Approach 1:
The thermowell is designed with different functional zones: a protected region where the sensing element is brazed to the thermowell at the fastening areas for structural support, and an exposed region where the measuring tip protrudes for thermal contact. This local differentiation of quality allows simultaneous achievement of protection and rapid response.
Solution Approach 2:
The sensing element is brazed to the thermowell at the fastening areas before exposure to the process medium. This preliminary structural connection ensures the sensing element can withstand flowing media while maintaining its protruding position for accurate temperature measurement.
3Reliability
If vacuum brazed solder joints are used to secure the sensing element, then connection reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs vacuum brazing, which changes the manufacturing parameters by creating a vacuum environment during the joining process. This parameter change enables reliable metallurgical bonds between the sensing element and thermowell, ensuring structural integrity and thermal contact while maintaining measurement accuracy.
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 design achieves fast response times and high measurement accuracy while ensuring process medium containment and safety, with the ability to detect potential leaks and faults, thus improving reliability and reducing hazards.
Implementation Method 1
The support tube and the first sensing element are connected to one another by solder joints, in particular by vacuum brazed solder joints
Data Source
AI summary
A temperature sensor having a support tube with a distal end having a first distal opening, with a proximal end having a first proximal opening and with a channel extending between the openings. The temperature sensor further comprises a sensing element, which is inserted through the first proximal opening into the channel and passes through it, so that a measuring tip of the sensing element passes through the first distal opening and protrudes beyond the distal end of the support tube, at least in sections. The support tube has a first fastening area on or near the distal end and a second fastening area on or near the proximal end. The sensing element is directly or indirectly tightly sealed to the support tube by solder joints on the first and second fastening areas.