Heat Pipe Wick Hydroforming with Hollow Mandrel and Sheath

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for forming rolled wire mesh wicks for heat pipes are time-consuming and costly, particularly due to the need for frequent changes in drawing die sizes as wick geometries evolve.

Innovation Solution

A forming assembly and method that utilize a mandrel and sheath to hydraulically expand and compress a wick mesh, allowing for the formation of wicks with minimal cost and time, and enabling quick adaptation to changing wick geometries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional drawing die methods are used to form wicks, then wicks can be manufactured with controlled dimensions and shape, but the process becomes time-consuming and costly due to frequent die changes

Engineering Contradiction:
Improvewick dimensions and shape controlVSAvoidwick manufacturing speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent uses hydraulic expansion of a mandrel to form the wick structure. A hollow mandrel is inserted into the wick mesh, and hydraulic pressure is applied to expand the mandrel, which in turn expands the wick mesh to the desired shape and dimensions. This eliminates the need for mechanical drawing dies and their frequent changes, thereby improving productivity while maintaining manufacturing precision.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Manufacturing precision

If traditional drawing die methods are used to form wicks, then wicks can be manufactured with controlled dimensions and shape, but the manufacturing cost increases due to die design and changeover requirements

Engineering Contradiction:
Improvewick dimensions and shape controlVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The hydraulic expansion method replaces expensive mechanical drawing dies with a reusable hollow mandrel. The mandrel can be repeatedly used for different wick geometries by simply adjusting hydraulic pressure parameters, eliminating the need to design and manufacture multiple expensive dies. This significantly reduces manufacturing costs while maintaining precise dimensional and shape control.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent controls wick geometry by changing hydraulic pressure parameters rather than changing physical tooling. By adjusting pressure magnitude, pressure application rate, and holding pressure, different wick shapes and dimensions can be achieved using the same mandrel, thereby reducing manufacturing costs associated with die design and changeover.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If wick geometries need to be adapted to changing reactor designs, then heat pipe performance can be optimized, but traditional methods require time-consuming die redesign and replacement

Engineering Contradiction:
Improvewick geometry adaptationVSAvoiddie changeover time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent enables rapid adaptation to different wick geometries by changing hydraulic process parameters (pressure levels, pressure profiles, expansion rates) rather than changing physical tooling. This allows quick adaptation to changing reactor designs and wick geometry requirements without time-consuming die redesign and replacement, significantly reducing loss of time while maintaining versatility.

Inventive Principle:
Principle #35Parameter changes

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 method allows for the efficient and cost-effective formation of wicks with uniform pore sizes and proper dimensions, suitable for use in heat pipes, while being highly repeatable and adaptable to various sizes and shapes.

Implementation Method 1

pressurizing the mandrel with the source of pressure to hydraulically expand the mandrel such that mandrel compresses the wick mesh against the sheath and forms the wick

Methodology Applied
Scientific EffectHydraulic expansion: Hydraulic Press

Implementation Method 2

The wick tube allows for the working fluid within the heat pipe to pass through it radially (such as after the latent heat is given off and the working fluid is absorbed by the wick) and along its axis (transferring the working fluid back toward the evaporator section with capillary action)

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP4139624B1Internal hydroforming method for manufacturing heat pipe wicks utilizing a hollow mandrel and sheath
Publication Date: 2025.06.04 WESTINGHOUSE ELECTRIC CORP
  • EP4139624B1 patent drawingFigure 1
  • EP4139624B1 patent drawingFigure 2
  • EP4139624B1 patent drawingFigure 3

AI summary

A forming assembly for forming a wick is disclosed. The forming assembly includes a tube inflatable to an inflated configuration. A wick mesh is configured to be wrapped about the tube. The forming assembly further includes a sheath positionable about the tube and the wick mesh. The tube and the sheath are configured to compress the wick mesh and form the wick based on the tube inflating towards the inflated configuration.