Double-Wall Tube Fitting for Fluid Path Isolation at Exit

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Solution Overview

Problem

Maintaining separation of fluids in double wall tubes is challenging, especially at the exit point, as existing technologies struggle to effectively isolate the inner and outer fluid paths.

Innovation Solution

A fitting design that includes a concentric arrangement of inner and outer tubes with a unique axial end configuration and apertures to maintain fluid isolation, featuring a seal between the fluid paths and a frustoconical outer portion to minimize pressure loss and heat transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a double wall tube structure is used to transport different fluids, then fluid transport capability is improved, but maintaining separation of fluids at the exit becomes difficult

Engineering Contradiction:

Improvefluid transport capabilityVSAvoidfluid separation maintenance

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The fitting is segmented into distinct functional zones: an inner portion for the first fluid path, an outer portion for the second fluid path, and a sealing portion with radially extending prongs that create separate exit apertures. This segmentation ensures that fluids exiting through different apertures remain separated even at the exit point.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A sealing portion with radially extending prongs acts as an intermediary element between the inner and outer portions. The prongs extend into the respective fluid paths and create physical barriers that maintain fluid separation at the exit, preventing mixing while allowing both fluids to be transported simultaneously.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Strength

If welding is used to connect double walled tubes, then connection strength is improved, but manufacturing complexity and difficulty increase

Engineering Contradiction:

Improveconnection strengthVSAvoidmanufacturing complexity

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The invention replaces complex welding operations with a mechanical insertion system. The fitting features an insertion end that receives the distal ends of inner and outer tubes, and a sealing portion with radially extending prongs that create mechanical interlocking and sealing through simple insertion, eliminating the need for welding while maintaining connection strength.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If chamfered joints are used for easy access, then ease of assembly is improved, but structural integrity may be compromised

Engineering Contradiction:

Improveease of assemblyVSAvoidstructural integrity

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The fitting employs a dynamic sealing mechanism where radially extending prongs are positioned to engage with the tube walls during insertion. The prongs can flex or adjust during the assembly process to accommodate minor misalignments, ensuring easy assembly while maintaining structural integrity through proper engagement.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentEP3358237B1Tube fitting

Publication Date: 2021.03.31 RTX CORP

Figure 1A
Figure 1B
Figure 2A~2B

AI summary

A fitting (50; 250) for a double wall tube (16) may comprise an inner portion (70) defining an inner fluid passage (60; 260). An outer portion (72) may be disposed concentrically around the inner portion (70) and may define an outer fluid passage (62; 262) between the outer portion (72) and the inner portion (70). The outer portion (72) may define a first aperture (64a; 264) disposed through a sidewall (78; 278) of the outer portion (72).