Brazed Plate Heat Exchanger Brazing Pattern to Prevent Burn-Through

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Solution Overview

Problem

Existing methods for producing brazed plate heat exchangers do not optimize the amount of brazing material applied at contact points, leading to suboptimal strength and increased risk of 'burn-through' due to inefficient material distribution.

Innovation Solution

A method involving calculating the force required at each contact point, using a screen to precisely apply the necessary amount of brazing material, and varying the application pattern to maximize strength while minimizing material usage, with a focus on larger amounts near port openings and decreasing amounts further away.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If brazing material is applied at contact points between heat exchanger plates, then the strength of brazing joints is improved, but the risk of burn-through of plates increases

Engineering Contradiction:
Improvebrazing joint strengthVSAvoidburn-through risk
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies different amounts of brazing material at different locations on the heat exchanger plates. Specifically, less brazing material is applied at contact points near port openings where burn-through risk is highest, while adequate material is applied at other contact points. This localized variation in material application resolves the contradiction by maintaining joint strength where needed while preventing burn-through in critical areas.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the parameter of brazing material quantity from a uniform application to a variable application based on location. By calculating and applying specific amounts of brazing material at each contact point, the patent optimizes the balance between achieving sufficient joint strength and preventing burn-through, thereby resolving the technical contradiction.

Inventive Principle:
Principle #35Parameter changes

2Strength

If more brazing material is used at contact points, then the overall strength of brazing joints is improved, but the amount of brazing material required increases

Engineering Contradiction:
Improvebrazing joint strengthVSAvoidbrazing material quantity
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The patent applies brazing material non-uniformly across different contact points, giving more material to contact points that require higher strength (those farther from port openings) and less material to contact points near port openings. This localized quality approach ensures adequate joint strength throughout the heat exchanger while minimizing total brazing material consumption.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies the principle of partial action by providing sufficient brazing material only where necessary for structural integrity. Rather than applying excessive material uniformly across all contact points, the patent calculates and applies the minimum necessary amount at each location, achieving required strength while reducing overall material usage.

Inventive Principle:
Principle #16Partial or excessive action

3Strength

If brazing material is applied close to port openings, then the strength near high-stress areas is improved, but the risk of burn-through at port openings increases

Engineering Contradiction:
Improvebrazing joint strength near port openingsVSAvoidburn-through risk at port openings
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent implements local quality by applying different quantities of brazing material based on the specific location and burn-through risk. At contact points near port openings where burn-through risk is highest, the patent applies reduced amounts of brazing material, while still providing adequate material at other contact points to maintain overall structural strength.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the parameter of brazing material quantity from uniform to variable based on location-specific requirements. By calculating the optimal amount for each contact point considering its proximity to port openings, the patent resolves the contradiction between needing strength near high-stress areas and preventing burn-through at vulnerable locations.

Inventive Principle:
Principle #35Parameter changes

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 reduces material usage, minimizes the risk of 'burn-through,' and achieves burst strength comparable to uniform brazing joint applications while maintaining structural integrity.

Implementation Method 1

Providing a screen for screen printing the brazing material onto the heat exchanger plates

Methodology Applied
Scientific EffectScreen printing:

Implementation Method 2

Brazing the stack of the heat exchanger plates in order to join the plates together

Methodology Applied
Scientific EffectBrazing: Brazing

Data Source

PatentEP3740338B1Method for producing a brazed plate heat exchanger
Publication Date: 2022.03.02 SWEP INT AB
  • EP3740338B1 patent drawingFigure 1~5

AI summary

A method for producing a brazed plate heat exchanger comprising a stack of heat exchanger plates provided with a pressed pattern adapted to provide contact points between neighboring heat exchanger plates, such that the heat exchanger plates are kept on a distance from one another under formation of interplate flow channels for media to exchange heat, wherein the interplate flow channels are in selective communication with port openings for the media to exchange heat and circumferentially sealed along an outer periphery in order to avoid external leakage, comprises the following method steps: a. Calculating the position of the contact points between neighboring plates; b. Calculating a force that must be transferred by each contact point when the heat exchanger is in use; c. Based on the method steps above, calculating a necessary amount of brazing material for each contact point; d. Providing a screen for screen printing the brazing material onto the heat exchanger plates, wherein the screen is provided with openings, the size, position, plate thickness and shape of which being adapted to provide the necessary amount of brazing material to each contact point; e. Screen printing the heat exchanger plates with brazing material using the screen; f. Stacking the heat exchanger plates in a stack; and g. Brazing the stack of the heat exchanger plates in order to join the plates together to form the heat exchanger.