Brazed Plate Heat Exchanger Brazing Layout for Burn-Through Control
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Solution Overview
Problem
Existing methods for producing brazed plate heat exchangers do not optimize the amount of brazing material at contact points, leading to suboptimal strength and increased risk of burn-through, despite efforts to minimize material usage and prevent external leakage.
Innovation Solution
A method involving calculating contact point positions and forces, determining necessary brazing material amounts, and using a screen for precise application of brazing material, with varying amounts applied based on force requirements and distance from port openings, and incorporating circumferential seals to prevent leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If brazing material is applied at contact points between ridges and grooves, then brazing joint strength is improved, but the risk of burn-through increases and brazing material consumption increases
Solution Approach 1:
The patent extracts the brazing material application from the contact point location and relocates it to adjacent positions (ridges or grooves nearby). This removal of brazing material from the direct contact point eliminates the harmful burn-through effect while preserving the bonding function through proximity-based material transfer during brazing.
Solution Approach 2:
The patent applies brazing material selectively at specific locations (ridges or grooves adjacent to contact points) rather than uniformly at all contact points. This localized application creates different material distributions based on local structural requirements, optimizing both strength and burn-through prevention at different positions.
2Object-affected harmful factors
If brazing material is applied close to but not at contact points, then burn-through risk is reduced, but brazing joint strength may be compromised
Solution Approach 1:
The patent uses the ridge or groove structure as an intermediary medium to transfer brazing material to the contact point during the brazing process. The brazing material is applied to the ridge or groove, which then acts as a reservoir or conduit to deliver the material to the contact point where bonding occurs, indirectly achieving both safety and strength.
3Strength
If more brazing material is used, then brazing joint strength increases, but brazing material consumption and cost increase
Solution Approach 1:
The patent applies brazing material partially - not at every contact point, but selectively at adjacent ridges or grooves. This partial application is sufficient to achieve the required brazing joint strength through material transfer during brazing, avoiding the excessive material consumption that would occur with full contact point coverage.
4Strength
If brazing material amount is increased, then overall brazing joint strength is higher, but plate erosion increases
Solution Approach 1:
The patent extracts the brazing material application from the vulnerable plate contact points, preventing direct erosion of the plate material. By applying material to ridges or grooves instead, the plate surface is protected from direct exposure to excessive brazing material and the associated erosive effects during brazing.
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 achieves maximum strength with minimal brazing material usage, reduces the risk of burn-through, and maintains burst strength while minimizing material costs and external leakage.
Implementation Method 1
Providing a screen for screen printing the brazing material onto the heat exchanger plates
Implementation Method 2
Brazing the stack of the heat exchanger plates in order to join the plates together
Data Source
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.