Extruded Heat Transfer Block for Faster Fluid Heating

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Solution Overview

Problem

Existing heat transfer devices for household appliances, such as coffee machines, face high manufacturing costs, material inefficiency, assembly difficulties, and poor versatility due to the use of separate steel and aluminum components with mismatched thermal expansion, leading to suboptimal thermal exchange and prolonged heating times.

Innovation Solution

A heat transfer device with an extruded aluminum block having an eight-shaped cross section, featuring internal pipes for the heating element and fluid passage, and external protuberances arranged in a helical configuration to reduce material usage and enhance thermal contact, allowing for efficient heat exchange without the need for a separate steel tube, and a manufacturing process involving extrusion, insertion of the heating element, and helical winding for assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate steel tube and aluminum casting are used with direct contact, then thermal exchange is achieved, but thermal expansion mismatch causes suboptimal contact and high manufacturing cost

Engineering Contradiction:
Improvethermal exchange efficiencyVSAvoidmanufacturing cost and assembly difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the steel tube and aluminum casting into a single integrated component where the steel tube is embedded within the aluminum casting. This eliminates the need for separate assembly and direct contact between two materials, resolving the thermal expansion mismatch issue while maintaining effective thermal exchange. The integrated design also simplifies manufacturing by reducing the number of parts and assembly steps.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The steel tube is nested within the aluminum casting, creating a concentric arrangement where the heating element resides inside the steel tube which is itself embedded in the aluminum casting. This nested structure maximizes thermal contact area while accommodating the different thermal expansion coefficients of the two materials, as each material can expand independently without compromising the thermal exchange interface.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If large amount of aluminum is used to ensure satisfactory heat exchange, then thermal exchange efficiency is improved, but thermal inertia increases and heating time is prolonged

Engineering Contradiction:
Improveheat exchange efficiencyVSAvoidheating time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The aluminum casting is designed with a specific geometric configuration that concentrates the aluminum material where it is most effective for heat exchange - surrounding the steel tube in a controlled manner. The protuberances and grooves create localized thermal contact zones that maximize heat transfer efficiency without requiring excessive aluminum volume, thereby reducing thermal inertia while maintaining effective heat exchange.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The helical winding of the steel tube and the curved protuberances in the aluminum casting create optimized thermal pathways. The curved geometry increases the surface area for heat exchange within a compact volume, improving heat transfer efficiency without increasing the overall mass of aluminum required, thus reducing thermal inertia and heating time.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Volume of moving object

If helical-wound configuration is used, then device dimensions are reduced, but manufacturing complexity increases

Engineering Contradiction:
Improvedevice dimensionsVSAvoidmanufacturing complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The steel tube is pre-formed into a helical configuration before being embedded in the aluminum casting. This preliminary formation of the helical shape allows for compact device dimensions while simplifying the final assembly process, as the helical structure is already in place and only requires embedding rather than complex post-assembly operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The aluminum casting acts as an intermediary that simplifies the manufacturing of the helical structure. Instead of directly forming a complex helical shape from two separate materials, the aluminum casting provides a matrix into which the pre-formed helical steel tube is easily embedded, reducing the overall manufacturing complexity while maintaining the space-saving helical configuration.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 reduces thermal inertia, lowers manufacturing costs, and enhances versatility by achieving faster heating times and improved thermal efficiency, making it suitable for various household applications like coffee machines and steam generators.

Implementation Method 1

a heat transfer device for transferring heat to a fluid... internally provided with a first pipe in which there is provided a resistive heating element

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

an aluminium alloy which facilitates the heat exchange between heating element and tube in which the water flows

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2033491B1A heat transfer device
Publication Date: 2009.12.09 I R C A S P A IND RESISTENZE CORAZZATE E AFFINI
  • EP2033491B1 patent drawingFigure 1~3
  • EP2033491B1 patent drawingFigure 4~5

AI summary

A device for transferring heat to a fluid with a heat generator comprising an electric resistance inserted in a first pipe integrally connected to a second pipe in which the fluid flows. The second pipe may comprise a steel tube coaxially inserted inside. First and second pipes are obtained inside a single block by means of an extrusion process.