In-Pipe Helical Fin Forming for Easier Double-Walled Tube Assembly

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Solution Overview

Problem

The existing methods for manufacturing heat exchange pipes with helical fins face challenges due to dimension errors when forming the thin plate into a helical shape, making it difficult to insert the helical-shaped plate into the pipe, which complicates the assembly process.

Innovation Solution

A method of manufacturing a fin-assembled tube by inserting a plate-shaped fin material into the tube and forming a helical fin by twisting it within the tube, eliminating the need for subsequent insertion and improving assemblability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the thin plate is formed into a helical shape before insertion, then the helical fin structure is created, but dimension errors occur making it difficult to insert into the pipe

Engineering Contradiction:

Improvedimension accuracy of helical finVSAvoidassemblability of fin-assembled tube

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

Instead of forming the helical fin first and then inserting it into the pipe (conventional method), the invention inverts the sequence by inserting the plate-shaped fin material into the pipe first and then forming the helical shape in place. This reversal eliminates dimension errors from pre-forming and simplifies assembly, directly resolving the technical contradiction between manufacturing precision and ease of manufacture.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The invention applies preliminary action by inserting the plate-shaped fin material into the pipe before forming the helical shape. This preliminary positioning ensures the fin material is correctly placed within the pipe, and subsequent helical forming occurs in the correct position, eliminating assembly difficulties while maintaining dimensional accuracy.

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If the helical fin is formed by twisting the fin material in the interior of the tube, then the assemblability is improved, but additional twisting equipment is needed

Engineering Contradiction:

Improveassemblability of fin-assembled tubeVSAvoidcomplexity of forming equipment

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The invention merges the fin insertion and helical forming operations into a single integrated process. By combining these steps, the need for separate insertion and forming equipment is reduced, and the overall device complexity is minimized while achieving improved assemblability. The plate-shaped fin material is inserted and formed in a continuous operation rather than as separate discrete steps.

Inventive Principle:

Principle #5Merging (Combining)

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 approach enhances the assemblability of the fin-assembled tube by forming the helical fin in place, reducing assembly complexity and potential errors, and allows for precise positioning and arbitrary twisting of the fin within the tube.

Implementation Method 1

a step of forming the helical fin by twisting the fin material in the interior of the tube

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP3508808B1Method for producing pipe having built-in fin, and method for producing double-walled pipe

Publication Date: 2023.08.30 MARELLI CABIN COMFORT JAPAN CORPORATION

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AI summary

In a method of manufacturing a fin-assembled tube (30) by arranging a helical fin (10) in an interior of a tube (20), a plate-shaped fin material (11) is inserted into the interior of the tube (20) and the helical fin (10) is formed by twisting the fin material (11) in the interior of the tube (20).