High Temperature Sensor Stabilizing Sleeve Design
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Solution Overview
Problem
High-temperature sensors face challenges in maintaining stability and reliability due to mechanical and thermal loads in exhaust gas flows of internal combustion engines, leading to potential oscillation and vibration issues, which can compromise measurement accuracy and durability.
Innovation Solution
A high-temperature measuring sensor arrangement featuring a sensor element in a protective tube with a stabilizing and fastening sleeve on the hot side and a second sleeve on the cold side, both with reduced diameters for joint connections, allowing for thermal expansion absorption without mechanical damage, combined with a thermally conductive filling and radiation shielding to enhance stability and response speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the protective tube is surrounded by a stiffening tube with higher thermal expansion coefficient, then mechanical stability at high temperature is improved, but the arrangement oscillates and vibrates during starting phase or non-high-performance operation
Solution Approach 1:
The stiffening function is divided into two segments: a first stabilizing and fastening sleeve for the hot side and a second stabilizing and fastening sleeve for the cold side. This segmentation allows each sleeve to be optimized for its specific thermal environment, preventing the oscillation issues that occur when a single stiffening tube is used across the entire temperature gradient.
Solution Approach 2:
Different stabilizing sleeves are provided for different locations along the protective tube - a first sleeve for the hot side near the measuring section and a second sleeve for the cold side near the connections. Each sleeve is positioned where it is most needed to provide local stabilization without causing unwanted mechanical contact and oscillation in other areas.
2Stability of the object's composition
If the stabilizing sleeve is firmly connected to the protective tube, then mechanical stability is improved, but thermal expansion causes mechanical destruction or damage
Solution Approach 1:
The connection between the stabilizing sleeves and the protective tube is made movable rather than fixed. The sleeves can move relative to the protective tube along its longitudinal axis, allowing the assembly to dynamically adjust to thermal expansion and contraction while maintaining mechanical stability. This dynamic connection prevents the mechanical destruction that would occur with a firmly fixed connection.
Solution Approach 2:
The design allows for changes in the positional parameters of the stabilizing sleeves relative to the protective tube during thermal cycles. The sleeves can shift position to accommodate thermal expansion, maintaining structural integrity while providing continuous stabilization. This parameter change capability resolves the contradiction between firm connection and thermal expansion tolerance.
3Stability of the object's composition
If the stabilizing sleeve has full diameter along the protective tube, then mechanical stability is improved, but thermal mass increases and response time slows
Solution Approach 1:
The stabilizing sleeves are provided with reduced diameters in specific areas rather than maintaining a uniform full diameter throughout. This allows the sleeves to have sufficient mass for mechanical stability in the connection areas while having reduced mass in the overhanging areas, thereby minimizing thermal mass and improving temperature response speed.
Solution Approach 2:
The stabilizing sleeves feature a varying cross-sectional dimension (reduced diameter in overhanging areas) along their length. This dimensional variation optimizes the balance between mechanical stability (provided by the full-diameter connection portions) and thermal response speed (improved by the reduced-diameter overhanging portions with lower thermal mass).
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 provides enhanced mechanical stability and rapid temperature response, reducing vibration and heat dissipation issues, ensuring reliable and accurate measurements in high-temperature environments.
Implementation Method 1
thermally induced expansions in the direction of the longitudinal axis between the protective cap and the first stabilizing and fastening sleeve can be accommodated without mechanical destruction or damage occurring
Implementation Method 2
the space between the sensor element and the protective tube cap is filled with a material with good thermal conductivity
Implementation Method 3
the stiffening tube is made of a material whose thermal expansion coefficient is higher than that of the material from which the protective tube is made
Data Source
AI summary
The invention relates to a high temperature measuring sensor arrangement, comprising a sensor element located in a shield tube with a measuring section exposed at the end of the shield tube and oriented towards the hot side and connections opposite this, facing towards the cold side, with a protective cap connected to the shield tube and enclosing the measuring section and a first stabilizing and fastening sleeve directed towards the hot side. According to the invention, the first stabilizing and fastening sleeve directed towards the hot side overlays the protective cap at the end thereof pointing towards the protective cap and provides stabilization against vibrational forces, wherein on the other hand, thermal expansions in the longitudinal axis direction are absorbed by the joint between the protective cap and the first stabilizing and fastening sleeve. Furthermore, a second stabilizing and fastening sleeve directed towards the cold side is provided, which overlays the shield tube at the connection-side end and supports said tube, wherein the first and/or the second stabilizing and fastening sleeve is designed with a reduced diameter in the region of the joint and overlay.