Heat Exchanger Brazing Fixture With Movable Top Plate
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Solution Overview
Problem
Heat exchangers experience bowing due to expansion during the brazing process, caused by clamping pressure, which affects the integrity and performance of the final product.
Innovation Solution
A heat exchanger brazing fixture with a baseplate, posts, and a top plate that allows for expansion without external load until a specific temperature is reached, using weights and spacers to manage the expansion and prevent bowing by moving the top plate as the heat exchanger expands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If constant clamping pressure is applied during brazing, then the heat exchanger components remain stable and properly positioned, but the sheets bow due to thermal expansion restriction
Solution Approach 1:
The top plate is designed to move vertically along the post, transitioning from a fixed clamping position to a movable position that accommodates thermal expansion. This dynamic adjustment allows the fixture to maintain stability while permitting shape changes during the brazing process.
Solution Approach 2:
The system changes the clamping force parameter from constant to variable. Initially, constant clamping pressure stabilizes the components. As temperature increases and expansion occurs, the top plate moves, automatically reducing the clamping force to prevent sheet bowing while maintaining component stability.
2Force
If the top plate is fixed in position, then clamping pressure is maintained for stable brazing, but the heat exchanger cannot expand freely causing deformation
Solution Approach 1:
The top plate transitions from a fixed to a movable state, enabling the system to maintain clamping pressure initially for stable brazing, then allow movement as expansion occurs to preserve dimensional accuracy and prevent deformation.
3Shape
If the heat exchanger is allowed to expand freely without clamping, then sheet bowing is prevented, but the components may shift or become misaligned during brazing
Solution Approach 1:
The fixture provides dynamic control where the top plate initially maintains clamping for alignment stability, then moves to allow free expansion for sheet flatness, achieving both component alignment and sheet flatness at different stages of the brazing process.
4Stability of the object's composition
If early clamping is applied to prevent movement, then component positioning is maintained, but thermal expansion causes bowing and stress
Solution Approach 1:
The system dynamically adjusts clamping pressure through the movable top plate, providing early clamping for component positioning stability, then releasing pressure to prevent structural integrity damage from excessive stress and bowing during thermal expansion.
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
Enables the heat exchanger to expand freely, reducing bowing and maintaining structural integrity by managing thermal expansion within the brazing fixture, thus improving the brazing process and product quality.
Implementation Method 1
when a heat exchanger resting upon the first surface of the baseplate expands during a brazing process
Implementation Method 2
increasing a temperature of the heat exchanger to perform the brazing process
Data Source
AI summary
A heat exchanger brazing fixture including a baseplate including a first surface and a second surface located opposite the first surface and a first post including a first end and a second end located opposite the first end. The first post is operably associated with the first surface of the baseplate at the first end. The A heat exchanger brazing fixture further including a top plate operably connected to the first post and separated from the first surface of the baseplate by a selected distance. The top plate being configured to move in a first direction along the first post when a heat exchanger resting upon the first surface of the baseplate expands during a brazing process.