Thermal Flowmeter Probe Bonding Without Silver Melt Bubbles
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Solution Overview
Problem
Existing methods for producing thermal flowmeter probes are prone to bubble formation during the melting of silver, leading to high waste rates and increased costs due to unusable probes, which complicates the achievement of a good thermal transition between the probe and the medium.
Innovation Solution
A method involving high-energy forming, such as explosion or magnetic forming, to create a cohesive connection between the probe sleeve and core, followed by a pulling process to adjust the diameter and smooth the surface, ensuring a stable and efficient thermal transition, while using materials like stainless steel and silver or copper for optimal thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If silver is melted in a sleeve to provide good thermal transfer, then thermal conductivity is improved, but bubble formation occurs leading to high waste rates
Solution Approach 1:
The invention changes the process parameters from melting silver (liquid state) to using pre-formed silver sleeves at controlled temperatures. This avoids bubble formation while maintaining thermal conductivity by using controlled thermal processes rather than complete melting.
Solution Approach 2:
The invention extracts the harmful element (bubbles) by avoiding the melting process that creates them. Instead of melting silver and risking bubble inclusion, the method uses pre-formed silver components that are inserted and bonded without melting, thereby eliminating the source of bubbles.
2Manufacturing precision
If high-energy forming is used to create material-bonded connection, then manufacturing precision is improved, but process complexity increases
Solution Approach 1:
The invention replaces complex mechanical forming processes with a simpler insertion and bonding process. The silver sleeve is inserted into the probe core and bonded using controlled thermal or adhesive bonding, eliminating the need for high-energy forming equipment while achieving equivalent or superior bonding quality.
Solution Approach 2:
The invention introduces an intermediary bonding agent or process (such as adhesive bonding or controlled thermal bonding) that facilitates the connection between the silver sleeve and probe core without requiring complex high-energy forming equipment. This intermediary process simplifies the overall manufacturing process.
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
This approach significantly reduces waste and costs by creating a mechanically stable and thermally efficient probe with improved thermal conductivity, enhancing the accuracy and reliability of mass flow measurements.
Implementation Method 1
at least one probe is used to measure the medium's temperature and at least one to heat the medium
Implementation Method 2
a thermocouple, which is configured to detect a temperature of the medium or to heat the medium
Data Source
Figure 1a
Figure 1b
Figure 1c
AI summary
The invention relates to a method (100) for producing a probe (10) of a thermal flowmeter (1) for measuring the mass flow of a medium in a measuring tube (2), a probe sleeve (11) having a longitudinal axis and a probe core (12) arranged loosely in the probe sleeve being provided. In at least one first method step (101), the probe sleeve, with respect to the longitudinal axis, is deformed over its entire circumference radially in the direction of the probe core by means of high-energy forming, an integrally bonded connection being produced between the probe sleeve and probe core, thus forming a rod (13), the rod constituting a main body (14), or a main body (14) being separated from the rod, the main body being used for probe manufacture, a deformation speed reaching values of greater than 100 m/s and in particular greater than 200 m/s, the high-energy forming being realised in particular by explosive forming or electromagnetic forming.