Collar Ribs for Heat Exchanger Header Tanks
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Solution Overview
Problem
Existing automotive heat exchanger designs with plastic tanks face challenges in achieving a fluid-tight seal and structural integrity under extreme temperature and pressure conditions, leading to packaging issues, stress concentrations, and potential failure due to the presence of a header inner flange which can create bending moments and stress concentrations.
Innovation Solution
The elimination of the header inner flange and utilization of a collar-style tube ferrule as a rib to stiffen the header and reinforce the thin-walled tube, reducing the overall thickness and depth of the heat exchanger while maintaining a fluid-tight seal, and using a gasket-mating surface coplanar with the header to minimize stress and improve crimping processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a header inner flange is used to provide a mating surface for brazing tubes to the header, then the header can be joined to tubes, but stress concentrations and bending moments are created under internal pressure
Solution Approach 1:
The patent removes the header inner flange entirely, extracting the source of stress concentrations and bending moments. The tube ferrule is repositioned to bear directly against the header face without requiring an inner flange, eliminating the problematic structural element while maintaining the brazing function.
Solution Approach 2:
The patent changes the dimensional arrangement by moving the tube ferrule closer to the header face and repositioning it in a different spatial configuration. This dimensional change allows the ferrule to bear directly against the header without creating the bending moments that occur with an offset inner flange.
2Ease of manufacture
If the tube ferrule is positioned farther from the header face to allow for brazing, then brazing can be performed, but the header becomes more susceptible to bending moments under pressure
Solution Approach 1:
The patent uses the tube ferrule itself as an intermediary element that serves dual functions: it provides the bearing surface against the header face and simultaneously acts as the brazing surface. This eliminates the need for a separate inner flange and allows the ferrule to be positioned optimally for both structural integrity and brazing accessibility.
3Reliability
If a trough is formed around the periphery of the header to accommodate the tank foot and gasket, then a fluid-tight seal is achieved, but the overall thickness and depth of the heat exchanger increases
Solution Approach 1:
The patent merges the functions of the trough, tank foot retention, and gasket sealing into a single integrated structural feature. The outer periphery of the header is formed to simultaneously accommodate the tank foot, retain the gasket, and provide the sealing surface, eliminating the need for a separate deep trough structure.
Data Source
AI summary
The present invention relates to the field of automotive heat exchangers, and, in particular, to heat exchanger tanks with headers. This invention eliminates the need for use of an inner flange on the header using a collar that also acts as a rib, thereby providing a compact foot plus header tank arrangement with lower stress on the gasket mating surface of the header and tank. The present invention also provides a method for providing improved headering means for automotive heat exchangers with plastic tanks and headers.