Cryogenic Thermometer Fastening Insert for Vibration and Thermal Expansion
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Solution Overview
Problem
Thermometers used in flowing media are prone to vortex-induced oscillations due to frequency mismatch between natural frequencies of the thermometer and vortex shedding, and existing solutions for mechanical mounts fail to provide reliable mechanical coupling and compensation for thermal expansion effects.
Innovation Solution
A fastening insert for thermometers, comprising a movable component parallel to the pipe socket axis, which compensates for thermal expansion effects while maintaining mechanical coupling, using a locking device to prevent rotational movement and incorporating a spring element or threaded bolt for stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the thermometer is made long with minimal diameter and thin walls for optimal thermal properties in cryogenic applications, then heat dissipation is reduced and measurement accuracy is improved, but the thermometer becomes highly susceptible to vortex-induced oscillations
Solution Approach 1:
A fastening insert is introduced as an intermediary component between the thermometer and the pipe socket. This fastening insert includes a holding element that engages with the thermometer and a locking device that prevents rotational movement, thereby providing mechanical support to the slender thermometer without requiring changes to its optimized dimensions
Solution Approach 2:
The mounting system is divided into separate functional components: the thermometer itself, the fastening insert with holding element, and the locking device. This segmentation allows the thermometer to maintain its optimized cryogenic design while the fastening insert provides the necessary mechanical support against vortex-induced oscillations
2Reliability
If mechanical mounts or absorbers are used to reduce sensitivity to vortex shedding, then the thermometer's natural frequency increases, but it becomes difficult to mount them with high coupling and their position cannot be guaranteed due to thermal expansion
Solution Approach 1:
The fastening insert incorporates a threaded bolt that allows for adjustable positioning along the longitudinal axis. This dynamic adjustment capability enables the system to accommodate thermal expansion and contraction of different components while maintaining reliable mechanical coupling and consistent position of the holding element relative to the thermometer
Solution Approach 2:
The threaded bolt acts as an adjustable intermediary that compensates for differential thermal expansion between components. By allowing positional adjustment, it maintains the integrity of the mechanical coupling without requiring complex mounting procedures or guarantees of fixed position under thermal stress
3Reliability
If the thermometer is firmly fixed to prevent vortex-induced vibrations, then mechanical coupling is improved, but compensation for thermal expansion effects becomes difficult
Solution Approach 1:
The threaded bolt provides dynamic adjustment capability along the longitudinal axis, allowing the holding element to maintain firm mechanical coupling with the thermometer while simultaneously accommodating thermal expansion and contraction of the pipe socket and fastening insert components
Solution Approach 2:
The system allows changes in the positional parameter of the holding element along the longitudinal axis through the threaded bolt mechanism. This parameter adjustment enables compensation for thermal expansion effects while maintaining stable mechanical coupling against vortex-induced vibrations
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 stability against vortex-induced vibrations and thermal expansion, allowing for optimal thermometer design with minimal heat dissipation and improved mechanical coupling, suitable for cryogenic applications.
Implementation Method 1
a spring element for compensating for thermal expansion effects
Implementation Method 2
at least one component of the fastening insert is designed and/or arranged such that the fastening insert is movable in the direction of a longitudinal axis through the pipe socket such that temperature effects due to different thermal expansion coefficients of different components of the thermometer can be compensated
Data Source
Figure 1~2
Figure 3a~3b
Figure 4a~4b
AI summary
The present invention relates to a fastening insert (6) for fastening a thermometer (1) in a tubular connection piece (3) of a measurement tube (2), comprising: - a retaining element (11) for fastening the thermometer (1) to the fastening insert (6); and - a locking means (8), which is designed to prevent rotational movement relative to the measurement tube (2). The invention also relates to an assembly, comprising: - a thermometer (1); and - a fastening insert (6) according to the invention. According to the invention, at least one component of the fastening insert (6) is designed and/or disposed such that the fastening insert (6) can be moved in the direction of the longitudinal axis of the tubular connection piece (3).