Header Tank Bevel Structure for Low-Heat Core Welding
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Solution Overview
Problem
Large, high-pressure, or high-temperature heat exchangers face increased weld bead size and heat input due to thicker header tanks, leading to expanded heat-affected areas and temperature rises in the core, necessitating additional countermeasures.
Innovation Solution
A through hole is provided in the nozzle attachment portion of the header tank, and a second inclined portion is added to the edge of the header tank's opening, reducing the bevel width and heat input during welding, thereby minimizing the weld bead size and heat-affected area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the thickness of the header tank is increased to ensure strength, then the strength of the header tank is improved, but the weld bead size and heat input to the core increase
Solution Approach 1:
The header tank is designed with non-uniform thickness: the nozzle attachment portion has increased thickness to ensure local strength where the through hole is provided, while the edge portion welded to the core maintains the original thickness. This local differentiation allows the header tank to have sufficient overall strength without increasing the weld bead size and heat input to the core.
2Strength
If the thickness of the header tank is increased, then the strength is improved, but the cross-sectional area of the weld bead increases
Solution Approach 1:
The header tank structure differentiates between regions: the nozzle attachment portion has greater thickness to compensate for material removal from the through hole, while the welding edge portion maintains original thickness. This ensures the weld bead cross-sectional area remains small, reducing welding complexity and heat input.
3Strength
If the thickness of the header tank is increased, then the strength is improved, but the welding time increases
Solution Approach 1:
By concentrating the increased thickness only at the nozzle attachment portion and maintaining original thickness at the welding edge, the weld bead size is kept small, which directly reduces welding time while still providing the necessary strength through localized thickening.
4Loss of substance
If a through hole is provided in the nozzle attachment portion, then the material of the header tank is reduced, but the strength of the header tank decreases
Solution Approach 1:
The through hole is provided in the nozzle attachment portion to reduce material usage, and the thickness is increased in this specific region to compensate for the strength loss. This localized thickness increase ensures the header tank maintains sufficient strength despite the material reduction from the through hole.
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 configuration reduces heat input and temperature rise in the core, eliminating the need for additional countermeasures against heat-related issues during welding, while maintaining the header tank's strength.
Implementation Method 1
heat input to the core during the welding
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
This heat exchanger includes a core and a header tank. The entire peripheral edge of an opening of the header tank welded to the core has a bevel inclined from the internal surface of the header tank toward the external surface thereof at a predetermined bevel angle. At least a portion of the peripheral edge of the opening of the header tank has a second inclined portion inclined from the external surface of the header tank toward the internal surface thereof at an angle larger than the predetermined bevel angle.