Heat Pipe Cut-Off Gas Plug for Mechanical Wear Elimination

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Solution Overview

Problem

Heat pipes face reliability issues due to mechanical parts that wear out and fail, especially when dealing with high temperatures, leading to decreased efficiency and potential damage to associated devices.

Innovation Solution

A sealed enclosure with a liquid storage tank, where access is controlled by a non-condensable gas that expands and contracts with temperature changes, allowing for a cut-off function without mechanical parts, ensuring the heat transfer fluid is stored safely at high temperatures and preventing overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical parts are used to control reservoir access and provide cut-off function, then the heat transfer fluid can be stored safely at high temperatures, but the mechanical parts wear out and fail over time, reducing reliability

Engineering Contradiction:
ImprovereliabilityVSAvoidservice life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent replaces mechanical parts (valves, diaphragms, pistons) with a gas plug that uses thermal expansion and contraction to control reservoir access. The gas plug expands when heated to close the passage and contracts when cooled to open it, providing a wear-free, maintenance-free mechanism that eliminates the reliability issues associated with mechanical components.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention utilizes changes in the physical parameter (volume) of the gas plug in response to temperature changes. As the gas plug heats up, its volume increases, causing it to move and close the passage to the reservoir. When it cools down, the volume decreases, allowing it to retract and open the passage. This parameter-based control mechanism avoids mechanical wear.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If mechanical parts are used for cut-off function, then heat transfer fluid storage is enabled, but mechanical wear and oxidation occur, offsetting reliability gains

Engineering Contradiction:
Improveprotect heat transfer fluidVSAvoidoxidation and corrosion
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

By replacing mechanical components with a gas plug mechanism, the invention eliminates surfaces that would otherwise be subject to oxidation and corrosion. The gas plug itself is not susceptible to these degradation mechanisms, and since it doesn't require sliding surfaces, seals, or moving mechanical parts, the harmful effects of oxidation and corrosion are avoided.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If the heat transfer fluid is continuously circulated to maximize heat capture, then thermal efficiency is improved, but the fluid degrades at high temperatures, reducing long-term performance

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidfluid stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention extracts the heat transfer fluid from the high-temperature environment by directing it into a reservoir when the gas plug closes the passage. This separates the fluid storage function from the heat transfer function, allowing the fluid to be protected from thermal degradation while maintaining efficient heat transfer during normal operation. The reservoir acts as a safe haven for the fluid away from the evaporator's high temperatures.

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

This solution enhances the reliability and longevity of heat pipes by eliminating mechanical failures and maintaining efficient heat transfer within predetermined temperature ranges, ensuring the heat pipe operates effectively and safely.

Implementation Method 1

a non-condensable gas that expands and contracts with temperature changes, allowing for a cut-off function

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

the liquid in the evaporator vaporizes, and the resulting vapor migrates to the condenser where it condenses, transferring heat to the cold source

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

the resulting vapor migrates to the condenser where it condenses, transferring heat to the cold source

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 4

when gravity is used, they are called 'thermosiphons,' while the term 'heat pipe' is used rather for mechanisms other than gravity

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP2981781B1Heat pipe comprising a cut-off gas plug
Publication Date: 2019.06.12 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP2981781B1 patent drawingFigure 1
  • EP2981781B1 patent drawingFigure 2A~2C
  • EP2981781B1 patent drawingFigure 3A~3C

AI summary

The invention relates to a device which comprises a sealed enclosure (18, 22, 26, 28) containing a fluid, (38) the liquid phase of which is in equilibrium with the vapour phase, the enclosure (18, 22, 26, 28) being divided into a first space (18, 22, 26) and a second space (28) communicating via a passage (32, 34), the second space (28) comprising a vessel (36) in communication with the passage (32, 34) and capable of containing the fluid in liquid phase when the device is in a predetermined position (D). The second space (28) contains a non-condensable gas (40) that is not soluble in the liquid phase of the fluid (38), and said gas (40) and the second space (28) are selected such that, when the device is placed in the predetermined position (D), said gas (40): at least partially fills the passage (32, 34) when the temperature of the gas is lower than a first predetermined temperature (Τlim max) of the temperature range; and clears the passage (32, 34) when the temperature of the gas is higher than the first predetermined temperature (Τlim max) of the temperature range.