Thermal Flowmeter Probe Forming Without Silver-Melt Bubbles

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Solution Overview

Problem

Existing methods for producing thermal flowmeter probes are prone to bubble formation during silver melting, leading to high scrap rates and increased costs due to the formation of undesired bubbles, which compromise the thermal transition between the probe and medium.

Innovation Solution

A method involving high energy rate forming, such as explosive or magnetic forming, to create a material-locking connection between the probe sleeve and core, ensuring a stable and efficient thermal transition, combined with subsequent steps like drawing, sealing, and connecting sleeve application to optimize probe structure and thermal conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If silver is melted in a sleeve to produce a probe, then good thermal transition between probe and medium is achieved, but bubbles form in the silver melt causing high scrap rates

Engineering Contradiction:

Improvethermal transition qualityVSAvoidscrap rate

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The invention changes the fundamental parameter of connection methodology from thermal melting to cold-forming (explosive or magnetic). This parameter change eliminates the phase transition that causes bubble formation while maintaining the goal of achieving good thermal transition through intimate material contact and material-locking connection.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces the thermal field (melting process) with a mechanical field (explosive shock wave or magnetic pulse). This substitution achieves the same bonding objective without the harmful thermal effects that cause bubble formation and material defects.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If high energy rate forming is used to create material-locking connection, then thermal transition is enhanced and scrap rates reduced, but process complexity increases

Engineering Contradiction:

Improveconnection stabilityVSAvoidforming process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention uses explosive or magnetic forming to rapidly complete the connection process in a single high-energy pulse, skipping the gradual heating and melting stages. This rushing through of the bonding process achieves intimate contact and material-locking connection instantly, reducing overall process time despite the high intensity of the forming step.

Inventive Principle:

Principle #21Skipping (Rushing through)

Solution Approach 2:

The invention utilizes the phase transition of the forming energy from a concentrated high-energy state (explosive detonation or magnetic pulse) to a dispersed bonding state. This phase transition of energy enables rapid material deformation and bonding without requiring sustained thermal input, simplifying the overall process control.

Inventive Principle:

Principle #36Phase transitions

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 scrap rates and enhances the thermal transition between the probe and medium, improving the reliability and cost-effectiveness of thermal flowmeter probes by achieving a mechanically stable and thermally conductive connection.

Implementation Method 1

the high energy rate forming is accomplished especially by means of explosive forming or magnetic forming

Methodology Applied

Scientific EffectExplosive forming: Explosive Welding

Implementation Method 2

Magnetic forming utilizes the phenomenon that time variable magnetic fields induce eddy currents in conductive materials, and the eddy currents for their part bring about a force on the material

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

time variable magnetic fields induce eddy currents in conductive materials, and the eddy currents for their part bring about a force on the material

Methodology Applied

Scientific EffectEddy currents: Eddy Currents

Implementation Method 4

a good thermal transition between probe core and probe sleeve is assured

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS11971281B2Method for producing a probe of a thermal flowmeter, probe of a thermal flowmeter, and thermal flowmeter

Publication Date: 2024.04.30 ENDRESS HAUSER FLOWTEC AG

AI summary

A method for producing a probe of a thermal flowmeter for measuring mass flow of a medium in a measuring tube, wherein a probe core is provided arranged loosely in a probe sleeve having a longitudinal axis, wherein the probe sleeve is deformed relative to the longitudinal axis completely radially in the direction of the probe core by means of high energy rate forming, wherein a material-locking connection between probe sleeve and probe core results and a rod is formed, wherein the rod represents a base body that is used for probe production, wherein a deformation speed reaches values greater than 100 m/s, and wherein the high energy rate forming includes explosive forming or magnetic forming.