Plate Heat Exchanger Pin-Recess Brazed Joint Assembly
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Solution Overview
Problem
The existing laminate heat exchanger assembly is time-consuming to assemble accurately and does not produce a satisfactory braze, especially when subjected to high-pressure fluids that apply tensile force on the joints.
Innovation Solution
The design features plates with integrally formed cylindrical pins and recesses of matching dimensions, where the pins have a smaller cross-sectional diameter and a chamfered end that fits within the recesses, allowing for self-location and improved brazing with a braze material applied between the pin ends and recesses, forming a robust joint with a fillet and consistent thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stacking and brazing process is used to assemble plates, then heat exchanger joints are formed, but the assembly is time-consuming and does not produce a satisfactory braze
Solution Approach 1:
The pin is pre-formed with a chamfered end before assembly. This preliminary preparation of the pin geometry enables the braze material to be drawn into the recess by capillary action during brazing, ensuring reliable joint formation without requiring complex assembly procedures or extended processing times.
Solution Approach 2:
A recess is introduced as an intermediary feature in the plate structure, positioned to receive the chamfered end of the pin. This recess acts as a mediator that guides and contains the braze material flow, ensuring proper braze joint formation and improving overall joint reliability while maintaining efficient assembly.
2Productivity
If high-pressure fluid is applied to the heat exchanger, then heat transfer performance is enhanced, but tensile force is applied on the brazed joints
Solution Approach 1:
The chamfered end of the pin is pre-formed to a specific geometry before assembly. This preliminary preparation creates an optimized stress distribution pattern in the braze joint, allowing the joint to better withstand the tensile forces generated by high-pressure fluid operation while maintaining heat transfer performance.
Solution Approach 2:
The joint structure combines the pin material, plate material, and braze material in a composite configuration. The recess and chamfer geometry create a multi-material composite joint that enhances overall joint strength and reliability under high-pressure conditions while maintaining thermal conductivity for effective heat transfer.
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 design facilitates faster and more accurate assembly, enhances the strength and reliability of the braze joints by allowing capillary flow of braze material, and maintains a consistent thickness, improving the overall performance under high-pressure conditions.
Implementation Method 1
allowing capillary flow of braze material
Data Source
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AI summary
A heat exchange plate (26) for a plate heat exchanger comprises a plate body (28) having a first side (30) and a second side (32) opposed to the first side (30). A plurality of pins (34) extends from the first side (30), and a plurality of recesses (38) is formed in the second side (32) for locating the pins (34) of a similar heat exchange plate (26) arranged adjacent thereto.