Flat Heat Transfer Pipe Structure to Prevent Fin Contact Loss
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Solution Overview
Problem
Existing heat exchangers face issues with deformation of flat elliptic heat transfer pipes due to internal pressure, leading to reduced contact with plate-like fins, increased assembly costs, and compromised heat transfer performance.
Innovation Solution
A heat exchanger design featuring flat-shaped heat transfer pipes with symmetric D-shaped through holes and a bulkhead partition, expanded using pipe-expanding burette balls, maintains pressure resistance and ensures close contact with plate-like fins, reducing ventilation resistance and enhancing heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a flat elliptic heat transfer pipe with a single through hole is used, then the pipe structure is simple, but the heat transfer pipe deforms due to internal pressure and close contact with the plate-like fin deteriorates
Solution Approach 1:
The single through hole of the flat elliptic heat transfer pipe is divided into multiple refrigerant flow passages (first and second passages). This segmentation increases structural rigidity to prevent deformation under internal pressure while maintaining the flat shape for good contact with plate-like fins. The bulkhead dividing the passages acts as a stiffening element that prevents oval deformation.
2Power
If the heat transfer pipe is made into a multi-hole structure with reduced size and diameter, then heat transfer rate increases, but pressure loss increases and manufacturing cost increases due to brazing
Solution Approach 1:
The patent changes the cross-sectional shape parameters of the heat transfer pipe from a simple flat ellipse to a specific shape with flat outer faces and curved side faces. The D-shaped through holes with bulkhead provide optimal balance between heat transfer surface area and structural integrity, allowing multi-hole configuration without excessive pressure loss. The pipe expanding method replaces brazing, reducing manufacturing cost.
3Power
If the heat transfer pipe size and diameter are reduced, then heat transfer performance improves, but assembly cost increases due to brazing
Solution Approach 1:
The patent replaces the thermal joining method (brazing) with a mechanical joining method (pipe expanding). The pipe expanding burette ball mechanically expands the refrigerant flow passages to create interference fit with the plate-like fin mounting holes, eliminating the need for brazing operations. This reduces assembly cost and complexity while maintaining secure connection of the reduced-size heat transfer pipe.
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 prevents deformation of the heat transfer pipes, improves assembly efficiency, and increases heat exchange capacity while reducing manufacturing costs and ventilation resistance.
Implementation Method 1
bonded to the plate-like fin by expanding diameters of the first and second refrigerant flow passages by a pipe-expanding burette ball
Implementation Method 2
heat transfer pipe inserted in a direction orthogonal to the plate-like fins and through which a refrigerant flows
Implementation Method 3
through which gas (air) flows and a flat-shaped heat transfer pipe inserted orthogonally into the plate-like fins and through which a refrigerant flows
Data Source
AI summary
A heat exchanger provided with a plurality of plate-like fins 2 arranged in parallel with a predetermined interval and a plurality of flat-shaped heat transfer pipes 3 inserted in a direction orthogonal to said plate-like fins 2 and through which a refrigerant flows, in which said heat transfer pipe 3 has an outside shape with a flat outer face arranged along an air flow direction and a section substantially in an oval shape and first and second refrigerant flow passages 31a, 31b made of two symmetric and substantially D-shaped through holes having a bulkhead 32 between the two passages inside, which is bonded to said plate-like fin 2 by expanding diameters of said first and second refrigerant flow passages 31a, 31b by a pipe-expanding burette ball.