Thermocouple Sensor With Exposed Junction for Heat Stability
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Solution Overview
Problem
Existing thermocouple sensors face challenges with improved accuracy and heat stability, particularly due to the location of the hot junction and the welding process, which limits their effectiveness in temperature measurement.
Innovation Solution
A thermocouple sensor design featuring a sensor block with passages for conductive wires forming a thermocouple junction that extends partially out from the outer surface, allowing for a reinforced and exposed junction, along with a weld preparation region for improved welding integrity and a heatshield for protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hot junction is located in a tucked away position requiring welding penetration and alignment, then the sensor structure is more protected, but the manufacturing complexity and alignment requirements increase
Solution Approach 1:
The hot junction is extracted from the traditional tucked-away position and relocated to extend through the sensor block to the outer surface. This allows the junction to be accessible without requiring complex welding alignment and penetration procedures, while still maintaining protection through the sensor block structure.
Solution Approach 2:
The sensor block is designed with pre-formed passages and an outer surface configuration that anticipates the welding process. The hot junction extends to the outer surface in advance, allowing welders to access and weld the junction directly without needing to align and penetrate through the entire sensor block during the welding process.
2Strength
If the hot junction is positioned to require full welding penetration, then the sensor achieves secure attachment, but the manufacturing time and alignment precision requirements increase
Solution Approach 1:
The hot junction is extracted from the interior of the sensor block and positioned to extend through the outer surface. This allows the welding operation to be performed on the exposed junction without requiring time-consuming penetration welding through the entire sensor block thickness, while still achieving secure attachment through the sensor block's structural design.
Solution Approach 2:
The sensor block is pre-configured with passages and surface features that guide the welding process. The hot junction extends to the outer surface in advance, allowing the welding operation to begin immediately without alignment and positioning time, thereby reducing overall manufacturing time while maintaining attachment strength.
3Reliability
If the thermocouple junction is fully enclosed in the sensor block, then the junction is protected from damage, but the heat transfer efficiency and measurement accuracy decrease
Solution Approach 1:
The sensor block provides full protection and enclosure for most of the thermocouple wires, while the hot junction specifically extends through the outer surface to create a localized exposed region. This local quality change allows the junction to be protected during installation while maintaining excellent heat transfer efficiency and measurement accuracy at the measurement point.
Solution Approach 2:
The hot junction extends from the interior three-dimensional space of the sensor block through the outer surface to the external environment. This dimensional transition allows the junction to maintain protection during the welding process while achieving direct thermal contact with the object being measured, thereby improving heat transfer efficiency and measurement accuracy.
4Manufacturing precision
If the sensor block requires alignment and clamping prior to welding, then the welding process is more controlled, but the installation complexity and time increase
Solution Approach 1:
The hot junction is extracted from the interior and positioned at the outer surface of the sensor block. This eliminates the need for complex alignment and clamping procedures during installation, as the exposed junction can be directly accessed and welded without requiring precise positioning of the entire sensor block, thereby simplifying installation while maintaining welding control.
Solution Approach 2:
The sensor block is pre-configured with the hot junction extending to the outer surface through specifically designed passages and surface features. This preliminary configuration eliminates the need for alignment and clamping operations during installation, allowing the sensor to be directly welded in position while maintaining manufacturing precision through the pre-established geometric relationships.
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 enhances accuracy and heat stability by allowing for a more stable junction and improved heat transfer, while reducing the elevation change of the cable, thus increasing longevity and response time.
Implementation Method 1
A voltage across the junction may vary as a function of temperature of the junction
Data Source
AI summary
A thermocouple sensor includes a sensor block having first and second ends, the sensor block defining an inner chamber. The sensor block comprises a first passage extending from the first end of the sensor block to the inner chamber, and a second passage extending from the inner chamber to an outer surface of the sensor block. The sensor also comprises a pair of conductive wires extending through the first passage into the inner chamber of the sensor block and extending into second passage from the inner chamber, the pair of conductive wires coupled together to form a thermocouple junction. The thermocouple junction may extend at least partially out from the second passage.