Brazed Temperature Probe Coating for Heat Exchanger Integration

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Solution Overview

Problem

Existing methods for integrating temperature sensors into heat exchangers, such as those described in FR3110099A1 and FR3110098A1, are expensive, difficult to implement, and risk damaging the sensors due to interactions with brazing materials, leading to inaccurate temperature measurements and structural thickening.

Innovation Solution

A method involving a thin protective coating applied to the temperature probe sheath before brazing, using PVD, CVD, or electrodeposition to prevent interaction with brazing alloys, allowing permanent integration without altering the heat exchanger's architecture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If temperature probes are inserted into grooves cut in metal sheets before brazing, then the temperature probes can be permanently attached to the structure, but the probes risk dissolution by the brazing alloy and the sheets experience significant thickening

Engineering Contradiction:

Improvetemperature measurement accuracyVSAvoidprobe dissolution by brazing alloy

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A protective coating is applied to the temperature probe sheath to act as an intermediary barrier between the probe and the brazing alloy. This coating prevents direct contact and dissolution of the probe by the molten brazing material, while still allowing thermal conduction for accurate temperature measurement.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The temperature probe assembly becomes a composite structure with multiple layers: the original sheath material, the protective coating layer, and the brazing alloy. This composite structure maintains the probe's integrity while enabling secure attachment to the heat exchanger plates.

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If grooves are cut in large metal sheets to accommodate temperature probes, then the probes can be positioned for measurement, but the machining becomes expensive and difficult to implement

Engineering Contradiction:

Improveprobe installationVSAvoidmachining complexity

Core Design Contradiction:

Ease of operationVSEase of manufacture

Solution Approach 1:

The protective coating step is extracted and applied separately to the probe before assembly, rather than requiring complex groove machining of the large metal sheets. This simplifies the manufacturing process by decoupling the probe preparation from the sheet fabrication.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If the sheathing thickness encapsulating the thermocouple is increased to prevent dissolution, then the probe integrity is improved, but the structural thickening of the separating sheet increases significantly

Engineering Contradiction:

Improveprobe integrityVSAvoidsheet thickness

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

Instead of increasing the sheath thickness throughout the entire probe, a localized protective coating is applied only to the portions of the probe that will be in contact with the brazing alloy. This provides the necessary protection against dissolution without adding significant thickness to the overall assembly.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The protective coating is applied in advance before the brazing operation, preparing the probe surface to resist dissolution. This preliminary protection allows the use of thinner sheathing while maintaining integrity during the brazing process.

Inventive Principle:

Principle #10Preliminary action

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

Ensures accurate and sustainable temperature measurement by preserving sensor integrity and avoiding structural thickening, while being cost-effective and easy to implement.

Implementation Method 1

a thin protective coating is deposited on said sheath, said coating being resistant to dissolution during brazing by an alloy used as filler metal

Methodology Applied

Scientific EffectChemical resistance:

Implementation Method 2

using PVD, CVD, or electrodeposition to prevent interaction with brazing alloys

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Implementation Method 3

using PVD, CVD, or electrodeposition to prevent interaction with brazing alloys

Methodology Applied

Scientific EffectChemical Vapour Deposition: Chemical Vapour Deposition

Implementation Method 4

using PVD, CVD, or electrodeposition to prevent interaction with brazing alloys

Methodology Applied

Scientific EffectElectrodeposition: Electrodeposition

Implementation Method 5

assembling by brazing a temperature probe to an element of the exchanger

Methodology Applied

Scientific EffectBrazing: Brazing

Data Source

PatentEP4499338B1Method for manufacturing a heat exchanger by brazing a temperature probe, corresponding heat exchanger

Publication Date: 2026.04.08 ALFA LAVAL GOLBEY SAS

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Figure 3(i)~3(ii)

AI summary

The invention relates to a method for manufacturing a heat exchanger, comprising a step of assembling, by brazing, a temperature probe (6) to an element of the exchanger (4), the temperature probe (6) comprising a sheath. The method further comprises a step, prior to the assembly step, in which a thin coating is deposited on the sheath in order to prevent dissolution thereof by an alloy used as filler metal for the brazing. The invention also relates to the heat exchanger which can be obtained by the method, and also to the temperature probe (6) prepared in order to carry out the above method.