Branching Flange Bellows-Fold Thermal Stress Absorption

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Solution Overview

Problem

Existing bypass flanges in heat exchangers, particularly in astronautical applications, face challenges in withstanding extreme temperature differences and mechanical stresses, leading to material embrittlement and potential ruptures due to the thinning and stress concentration caused by material stretching during the manufacturing process.

Innovation Solution

A branching flange with a bellows-fold intermediate section that absorbs differential expansions, providing axial and radial softening, and allowing for a homogeneous weld bead, ensuring the flange can withstand thermal and mechanical stresses without material thinning or dimensional rupture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If material stretching is used to form the collar during manufacturing, then the collar shape is achieved, but material thinning occurs leading to embrittlement and potential ruptures

Engineering Contradiction:
Improvecollar shapeVSAvoidmaterial strength
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The patent introduces a bellows-fold intermediate section with multiple concentric folds that provides flexibility and stress absorption. This flexible structure allows the flange to accommodate thermal expansion and mechanical stresses without causing material thinning or embrittlement, resolving the contradiction between achieving the required collar shape and maintaining material strength.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the geometric parameters of the intermediate section by introducing multiple concentric folds with specific radii (R1, R2, R3) and spacing. This parameter modification allows the structure to absorb stresses through controlled deformation of the folds, preventing material failure while maintaining the necessary collar geometry for proper flange function.

Inventive Principle:
Principle #35Parameter changes

2Strength

If the flange is rigid to maintain structural integrity, then strength is improved, but thermal expansion stresses cause plasticization and loss of elastic qualities

Engineering Contradiction:
Improvestructural integrityVSAvoidelastic qualities
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The patent transforms the rigid flange structure into a dynamic one by incorporating a bellows-fold intermediate section that can flex and deform elastically. The multiple concentric folds allow the structure to dynamically absorb thermal expansion stresses through controlled movement, preventing plasticization while maintaining overall structural integrity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The bellows-fold intermediate section acts as a flexible element between the rigid front and rear sections. This flexible structure accommodates thermal expansion and mechanical stresses through elastic deformation of the folds, preventing loss of elastic qualities while maintaining the strength needed for structural integrity.

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If the intermediate section has a complex bellows-fold shape to absorb stresses, then stress absorption is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvestress absorptionVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The bellows-fold intermediate section, while geometrically complex, can be manufactured using standard metal forming techniques. The concentric folds are created through controlled deformation processes that, although requiring precision, do not necessitate complex multi-step manufacturing sequences. The resulting structure provides excellent stress absorption capability.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent defines specific geometric parameters for the bellows-fold section (radii R1, R2, R3; spacing e; angle alpha) that optimize stress absorption. These parameters can be adjusted based on application requirements, allowing the design to be adapted to different manufacturing capabilities while maintaining reliable stress absorption performance.

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 solution effectively absorbs mechanical and thermal stresses, enhancing the flange's integrity and preventing embrittlement, allowing it to maintain its structural integrity during cycles and withstand extreme temperature variations.

Implementation Method 1

the bypass, and in particular the flange mounted on the main pipe to form this bypass, must withstand extreme temperatures, and temperature differences causing expansion

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

the intermediate section having the shape of a bellows fold, it makes it possible to achieve the absorption of the differential expansions, by constituting an axial and radial softening of the flange

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 3

the free end having a circular outline capable of being mounted by plane welding along a circular opening of a wall of the main pipe

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP2098773B1Branching flange, branching device comprising a main tube and said branching flange and method of connecting such a branching flange by welding
Publication Date: 2011.09.07 SN DETUDE & DE CONSTR DE MOTEURS DAVIATION (S N E C M A)
  • EP2098773B1 patent drawingFigure 1~3
  • EP2098773B1 patent drawingFigure 2
  • EP2098773B1 patent drawingFigure 4

AI summary

The flange (120) has an axial and radial softening zone including a rear section (122) provided with a radial fixation plate (122a), and a front section (126) whose free end has a flat circular contour for being mounted around a flat circular non-coaxial opening (132) in a wall of a main pipe (130) by a welding seam (129). The zone has an intermediate section with annular walls (124a, 124b) that form an acute angle towards axial internal passages (121a-121c). The section (126) has an annular wall (126b) that is extended radially around a rotational axis. Independent claims are also included for the following: (1) a connecting device for connecting main and secondary pipes, comprising a connecting flange (2) a method for connecting a main pipe and a connecting flange.