Clamshell Heat Exchanger Fastener for Thermal Stress Relief
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Solution Overview
Problem
High-efficiency furnaces face stress and potential failure due to thermal gradients in clamshell heat exchangers, leading to efficiency losses and reduced operational life, as conventional joining methods concentrate stress and may cause fatigue and leakage.
Innovation Solution
A clamshell heat exchanger design with through-holes and fasteners that allow relative lateral motion between clamshell halves, reducing stress concentrations and enabling efficient heat transfer while maintaining a seal, using an eyelet fastener configuration to secure the halves and accommodate thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional joining methods are used to fasten clamshell halves, then the heat exchanger maintains structural integrity, but stress concentrations occur leading to fatigue and leakage
Solution Approach 1:
The fastener system is designed to allow dynamic movement between clamshell halves during thermal expansion and contraction. The fasteners accommodate lateral motion while maintaining the seal, transforming the static rigid connection into a dynamic adaptive connection that responds to thermal cycles without causing stress concentrations or fatigue failure.
2Reliability
If rigid joining methods are used to secure clamshell halves, then the seal region maintains sealing effectiveness, but thermal expansion causes stress and potential failure
Solution Approach 1:
The fastening system parameters are designed to allow controlled movement within specific ranges. The fasteners maintain sufficient constraint to preserve sealing effectiveness while permitting limited lateral motion to accommodate thermal expansion, optimizing the balance between sealing reliability and stress resistance through parameter optimization.
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
The solution extends the operational life of the heat exchanger by reducing stress and leakage, maintaining high efficiency through effective heat transfer and preventing premature failure, with the eyelet fastener allowing minimal lateral motion to mitigate thermal stress.
Implementation Method 1
The fastener is configured to rigidly join the first clamshell half to the second clamshell half while allowing relative lateral motion between said first and said second clamshell halves
Implementation Method 2
The heat exchanger is located within the cabinet and configured to transfer heat from a burned fuel to the air
Data Source
AI summary
A clamshell heat exchanger includes a first clamshell half and a second clamshell half. The first and second clamshell halves each include a through-hole therein. The first and second clamshell halves form a passageway, with a seal region located between portions of the passageway. A fastener is located within the first and second through-holes within the seal region. The fastener is configured to rigidly join the first clamshell half to the second clamshell half while allowing relative lateral motion between said first and said second clamshell halves.