Flexible Heat Pipe With Bellows Structure Reducing Force Reaction

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Solution Overview

Problem

Existing heat pipes are not flexible enough to avoid damage or decoupling from cooler and heater blocks, requiring a force reaction reduction to less than 2.5 N for flexibility, which is challenging for mass production due to complex designs and internal stress issues.

Innovation Solution

A heat pipe design with a flexible bellows structure, including perforated walls, offset wick placement, and additional through holes, which reduces force reaction and stress, allowing for flexibility while maintaining thermal performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a traditional flat heat pipe design is used, then the structure is simple and suitable for mass production, but the force reaction is high (25-50 N) causing damage or decoupling from cooler and heater blocks

Engineering Contradiction:
Improvesuitability for mass productionVSAvoidforce reaction
Core Design Contradiction:
Ease of manufactureVSForce

Solution Approach 1:

The patent introduces a curved or bellows-like structure in the heat pipe design, replacing the traditional flat configuration. This curvature allows the heat pipe to flex and accommodate relative movements between the cooler and heater blocks, reducing the force reaction from 25-50 N to below 2.5 N while maintaining structural integrity and thermal performance.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Force

If a bellow shape section is attached to the heat pipe to reduce force reaction, then flexibility is improved, but the fabrication complexity increases and mass production becomes difficult

Engineering Contradiction:
Improveforce reactionVSAvoidfabrication complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent merges the bellows structure directly into the heat pipe envelope, creating an integrated design where the flexible section is not a separate attachment but an inherent part of the heat pipe structure. This integration simplifies the fabrication process by eliminating additional assembly steps while maintaining the flexibility needed to reduce force reaction below 2.5 N.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If the wick is located near the outer wall to simplify structure, then manufacturing is easier, but elongation and stress increase leading to destruction of the heat pipe

Engineering Contradiction:
Improvestructural simplicityVSAvoidresistance to elongation and stress
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent positions the wick in the central region of the heat pipe rather than near the outer wall. This central positioning places the wick in the neutral plane during bending, minimizing elongation and stress on the wick material. This local optimization of wick placement maintains structural simplicity while significantly improving resistance to elongation and stress, preventing heat pipe destruction.

Inventive Principle:
Principle #3Local quality

4Force

If additional springs are added to the heat pipe to reduce force reaction, then flexibility is improved, but internal space is occupied reducing thermal performance

Engineering Contradiction:
Improveforce reactionVSAvoidthermal performance
Core Design Contradiction:
ForceVSLoss of energy

Solution Approach 1:

The patent extracts the need for additional mechanical components like springs by integrating the flexibility function directly into the heat pipe envelope through the curved/bellows structure. This eliminates the need for separate springs that would occupy internal space and interfere with thermal performance, achieving force reaction reduction below 2.5 N while preserving the internal volume available for heat transfer.

Inventive Principle:
Principle #2Taking out (Extraction)

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 heat pipe achieves a force reaction of less than 2.5 N, ensuring flexibility without compromising thermal performance, making it suitable for mass production with a simple design.

Implementation Method 1

transporting a condensed working fluid from a condenser end to an evaporator end

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

condensation of a gas phase of the internal media on the wick

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

transfer heat over long distances due to a combination of processes

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4237780B1Flexible heat pipe
Publication Date: 2024.07.31 HUAWEI TECH CO LTD
  • EP4237780B1 patent drawingFigure 1A
  • EP4237780B1 patent drawingFigure 1B~1C
  • EP4237780B1 patent drawingFigure 1D~1E

AI summary

Provided is a heat pipe (100, 200, 300, 400, 500, 600, 700) having an envelope (102, 202, 302) with working fluid, an inner layer of wick (108, 206, 504) and a flexible bellows (104). The envelope has a condenser end, an evaporator end, and an adiabatic section in between the condenser and the evaporator ends. The inner layer of wick is arranged on an inner surface of the envelope for transporting condensed working fluid from the condenser end to the evaporator end. The adiabatic section comprises a perforation of walls of the envelope forming a passage for a vapor and a compressed area (106, 204, 502) where walls of the envelope are offset towards a central axis of the envelope. The flexible bellows covers the compressed area and defines a channel (112) for the vapor with ends of the flexible bellows sealed to walls of the envelope outside of the perforation.