Plate Heat Exchanger Partial Brazing for Leak Detection
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Solution Overview
Problem
In plate heat exchangers with double wall structures, the air layer between metal plates reduces heat transfer performance and makes it difficult for leaked fluid to escape and be detected, as the plates are not metal-joined, leading to thermal resistance and detection issues.
Innovation Solution
The plate heat exchanger design includes partially brazing the metal plates together at specific points to form outflow passages that communicate with the outside, reducing thermal resistance and allowing leaked fluid to escape without mixing with other fluids, while maintaining effective heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the pair of metal plates are brought into tight contact with each other to improve heat transfer performance, then heat transfer performance is improved, but leaked fluid cannot easily flow out and be detected
Solution Approach 1:
The space between the metal plates is segmented into multiple regions: heat transfer regions where plates are in tight contact for efficient heat exchange, and outflow passage regions where gaps are intentionally created to allow leaked fluid to escape and be detected. This segmentation resolves the contradiction by providing dedicated zones for each function.
Solution Approach 2:
Different regions of the plate structure have different contact qualities between metal plates. In heat transfer regions, plates are in tight contact to minimize thermal resistance, while in outflow passage regions, plates are separated to create fluid pathways. This local variation in contact quality allows simultaneous optimization of heat transfer and leak detection.
2Reliability
If the pair of metal plates are not metal-joined together to allow leaked fluid to flow out, then leak detection is enabled, but thermal resistance increases and heat transfer performance deteriorates
Solution Approach 1:
The plate structure is divided into functional zones: brazed portions where metal plates are joined to ensure thermal contact, and outflow passage portions where plates remain separated to enable fluid escape. This segmentation allows the system to achieve both leak detection capability and acceptable heat transfer performance.
Solution Approach 2:
The invention merges two previously separate functions into a unified plate structure: the heat transfer function (achieved through brazed portions) and the leak detection function (achieved through outflow passages). This integration allows both functions to coexist within the same component system.
3Loss of energy
If the metal plates are partially brazed together to reduce thermal resistance, then heat transfer performance is improved, but the complexity of manufacturing increases
Solution Approach 1:
The brazing process is segmented to apply brazing material only to specific portions of the plates rather than the entire surface. This selective brazing reduces the amount of brazing material needed and simplifies the manufacturing process while still achieving the thermal contact necessary for heat transfer in the required regions.
Solution Approach 2:
Instead of brazing the entire plate surface, the invention applies partial brazing only to the portions where thermal contact is needed. This partial action approach reduces manufacturing complexity and material costs while maintaining sufficient heat transfer performance for the application.
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 enhances heat transfer performance by reducing thermal resistance and enables efficient detection of leaks by allowing fluids to flow out and be detected externally, even in cases of corrosion or freezing.
Implementation Method 1
The two metal plates are partially brazed together at a brazed portion such that a plurality of outflow passages are formed between the two metal plates along overlapping surfaces thereof
Implementation Method 2
The plurality of heat transfer plates are partially brazed together such that a first flow passage through which first fluid flows and a second flow passage through which second fluid flows are alternately arranged
Data Source
AI summary
A plate heat exchanger includes heat transfer plates each of which has openings at four corners thereof, and which are stacked together. The heat transfer plates are partially brazed together such that a first flow passage through which first fluid flows and a second flow passage through which second fluid flows are alternately arranged, with an associated heat transfer plate interposed between the first and second flow passages. The openings at each of the four corners communicate with each other, thereby forming a first header and a second header, the first header allowing the first fluid to flow into and flow out of the first flow passage, the second header allowing the second fluid to flow into and flow out of the second flow passage.