Heat Exchanger Header Deformations for Joint Strength
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Solution Overview
Problem
Aluminum heat exchangers face strength loss due to re-crystallization during brazing, leading to reduced pressure resistance and durability, which is exacerbated by the need for thicker materials to counteract stress, resulting in increased costs and challenges with the crimping process.
Innovation Solution
The introduction of deformations such as grooves, notches, or ribs on the header side walls after the brazing process enhances the stiffness and strength of the header-to-tank joint without increasing material thickness, allowing the heat exchanger to withstand elevated pressures and repetitive cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If material thickness is increased to resist pressure after brazing, then pressure resistance is improved, but manufacturing cost and crimping process complexity increase
Solution Approach 1:
The patent applies local quality by introducing deformations (ridges, grooves, or protrusions) only at specific locations on the header surface where crimping occurs, rather than uniformly thickening the entire header. This localized structural modification provides enhanced crimping resistance and pressure resistance at critical areas while maintaining thin material thickness elsewhere, thus avoiding increased manufacturing complexity and cost.
Solution Approach 2:
The patent transitions from a two-dimensional flat header surface to a three-dimensional structured surface by adding deformations such as ridges, grooves, or protrusions. This dimensional change creates additional mechanical interlocking features that enhance crimping resistance without requiring increased material thickness, effectively solving the contradiction between strength and manufacturing simplicity.
2Reliability
If material thickness is increased to maintain durability under elevated pressure, then durability is improved, but manufacturing cost increases
Solution Approach 1:
The patent uses local quality by concentrating structural reinforcements (deformations) only at the crimping zones where durability is most needed, rather than uniformly increasing material thickness across the entire header. This localized approach maintains high durability under elevated pressure while minimizing material consumption and manufacturing cost.
Solution Approach 2:
The patent creates a composite structure by combining the base header material with deformation features (ridges, grooves, or protrusions) that provide enhanced mechanical properties. This composite approach achieves superior durability and pressure resistance without requiring additional material quantity, as the deformations create mechanical interlocking that compensates for thin material thickness.
3Strength
If deformations are added to header side walls after brazing, then stiffness and strength of header-to-tank joint are improved, but manufacturing process steps increase
Solution Approach 1:
The patent applies preliminary action by forming deformations on the header surface before the crimping operation. These pre-formed deformations (ridges, grooves, or protrusions) are prepared in advance through stamping or rolling processes, so that during crimping the deformations automatically engage with the tank to provide enhanced mechanical interlocking and joint strength, eliminating the need for complex real-time adjustments during assembly.
Solution Approach 2:
The patent changes the surface parameter of the header by introducing geometric deformations (ridges, grooves, or protrusions) that modify the mechanical interaction between header and tank. These parameter changes enhance joint strength and stiffness without fundamentally altering the manufacturing process flow, as the deformations can be created through simple stamping or rolling operations that integrate easily into existing production lines.
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 solution provides increased pressure resistance and durability at the header-to-tank joint, maintaining performance under high stress conditions without the need for thicker materials, thereby extending the product lifespan and maintaining assembly efficiency.
Implementation Method 1
The deformations on the side wall of the header increase the stiffness of the material. This provides additional strength to the header to tank joint area to a level that even in highly elevated stress and pressure conditions, the crimping joint, is able to resist
Data Source
AI summary
The present invention has its object to provide a heat exchanger with plastic tanks type, wherein a seal member is regularly compressed and hooks or tabs of header core crimped in a uniform fashion.Deformations predominantly located in the large sides or sides adjacent to the tank foot of the header, are formed and distributed in the inner or outer wall. The deformations in the periphery, or more particular, on the outside of the header wall, are formed after the brazing process.