Bent-Header Heat Exchanger Fins That Prevent Pipe Deformation

Solution Overview

Problem

The bending step in heat exchanger fabrication applies a compressive force to the inner side of bending, leading to deformation of heat transfer pipes and a decrease in heat exchange efficiency.

Innovation Solution

Incorporating fins with weak portions, such as fin-bent portions or notches, that have lower rigidity and are more readily deformed than other portions, allowing them to absorb compressive forces and prevent deformation of heat transfer pipes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If headers are bent to distribute refrigerant, then heat exchanger installation flexibility is improved, but heat transfer pipes adjacent to bent sections deform due to compressive force

Engineering Contradiction:

Improveinstallation flexibilityVSAvoidheat transfer pipe deformation

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The fin is pre-formed with a weak portion (fin-bent portion or notch) at the location that will correspond to the inner side of the header bend. This preliminary structural preparation allows the fin to absorb compressive forces during the bending process, preventing the force from being transmitted to the heat transfer pipes and causing their deformation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The fin with its weak portion acts as an intermediary element between the header and the heat transfer pipes. During bending, the fin's weak portion deforms first, absorbing the compressive force and preventing it from reaching the heat transfer pipes, thus protecting them from deformation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If headers are bent during fabrication, then heat exchanger configuration flexibility is improved, but heat exchange efficiency decreases due to pipe deformation

Engineering Contradiction:

Improveconfiguration flexibilityVSAvoidheat exchange efficiency

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The fin is pre-formed with a weak portion (fin-bent portion or notch) at the location that will correspond to the inner side of the header bend. This preliminary structural preparation allows the fin to absorb compressive forces during the bending process, preventing the force from being transmitted to the heat transfer pipes and causing their deformation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The fin with its weak portion acts as an intermediary element between the header and the heat transfer pipes. During bending, the fin's weak portion deforms first, absorbing the compressive force and preventing it from reaching the heat transfer pipes, thus protecting them from deformation.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If fins are made rigid to maintain heat transfer efficiency, then heat transfer performance is improved, but fins are more susceptible to breakage during bending

Engineering Contradiction:

Improveheat transfer performanceVSAvoidfin resistance to breakage

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The fin is designed with non-uniform structure: most of the fin maintains high rigidity for effective heat transfer, while a specific localized region (the weak portion at the inner side of the bend) has reduced rigidity. This local quality differentiation allows the fin to be both strong for heat transfer and vulnerable at the critical bending location to prevent breakage.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The fin is pre-formed with a weak portion (fin-bent portion or notch) at the location that will correspond to the inner side of the header bend. This preliminary structural preparation allows the fin to absorb compressive forces during the bending process, preventing the force from being transmitted to the heat transfer pipes and causing their deformation.

Inventive Principle:

Principle #10Preliminary action

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 use of fins with weak portions effectively absorbs compressive forces during the bending process, preventing deformation of heat transfer pipes and maintaining heat exchange efficiency.

Implementation Method 1

the weak portion is more readily deformed than the other portions in response to a change in the distance between the adjacent two of the first heat transfer pipes

Methodology Applied

Scientific EffectDeformation: Deformation

Data Source

PatentUS20250164192A1Heat exchanger, and method for manufacturing heat exchanger

Publication Date: 2025.05.22 MITSUBISHI ELECTRIC CORP

AI summary

A heat exchanger includes a first header having a first bent section and a first linear section extending from the first bent section, a second header having a second bent section bent in the same direction as the first bent section and opposed to the first bent section and a second linear section extending from the second bent section, first heat transfer pipes arranged along the first bent section and connecting the first bent section and the second bent section, and fins that each disposed between two adjacent first heat transfer pipes and that transfer heat from the first heat transfer pipes. At least one of the fins has a weak portions having a lower rigidity than the other portions of the fin, and being more readily deformed than the other portions in response to a change in the distance between the two adjacent first heat transfer pipes.