Pipe Connection With Radial Interference Shoulders

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Solution Overview

Problem

Existing pipeline connections face challenges in achieving strong axial and bending resistance while maintaining a small wall thickness and effective fluid sealing, as most load-bearing threads are concentrated at the thread ends, and sealing requires precise fitting of nibs into grooves.

Innovation Solution

The pipeline sections feature short axial thread lengths with long gaps between threads and abutments, utilizing radial interference shoulders and 360° nibs and grooves for alignment and sealing, allowing for a strong, lightweight design with reduced wall thickness and enhanced fluid sealing through interference fits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If pipe sections use conventional long threads for connection, then axial and bending resistance is improved, but wall thickness increases and sealing precision deteriorates

Engineering Contradiction:
Improveaxial and bending resistanceVSAvoidnib-groove sealing fit
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The connection structure is segmented into distinct functional zones: short load-bearing threads for axial connection, long gaps for stress distribution, and radial interference shoulders for bending resistance. This segmentation allows each zone to optimize its specific function without compromising others, enabling reduced wall thickness while maintaining strength and sealing precision

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from conventional axial thread loading to multi-dimensional load distribution by introducing radial interference shoulders and circumferential nib-groove joints. This dimensional shift allows bending and axial loads to be distributed across multiple planes, reducing the need for thick walls while maintaining structural integrity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Loss of substance

If pipe sections use reduced wall thickness, then material usage and cost are reduced, but axial and bending resistance deteriorates

Engineering Contradiction:
Improvematerial usageVSAvoidaxial and bending resistance
Core Design Contradiction:
Loss of substanceVSStrength

Solution Approach 1:

The pipe connection structure employs local quality enhancement at critical stress points through radial interference shoulders and circumferential nib-groove joints, while maintaining reduced wall thickness in non-critical areas. This localized strengthening allows material reduction overall while preserving axial and bending resistance where needed

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The connection structure functions as a composite system combining threaded sections, interference-fit nibs, and radial shoulders working together. This composite approach distributes loads across multiple mechanisms, enabling thin-walled pipes to achieve the strength of thicker conventional designs through synergistic structural elements

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If pipe sections use conventional sealing methods, then manufacturing simplicity is maintained, but sealing reliability deteriorates

Engineering Contradiction:
Improvesealing structure complexityVSAvoidfluid sealing
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The radial interference shoulders and circumferential nib-groove joints create self-aligning and self-sealing characteristics. During assembly, the interference fit automatically positions the nibs in the grooves and creates the seal, eliminating the need for complex alignment procedures or additional sealing components, thus maintaining manufacturing simplicity while enhancing sealing reliability

Inventive Principle:
Principle #25Self-service

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 configuration provides high axial and bending resistance, minimizes pipe wall thickness, and ensures a reliable fluid seal by distributing loads and improving alignment and interference fit between nibs and grooves, reducing material usage and cost.

Implementation Method 1

Each nib is sequentially deflected into alignment with a groove by a tapered pipe internal wall leading to a radial abutment surface, so as the pipe sections become fully mated, the radial interference abutments deflect the nibs and grooves into accurate alignment

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

For good sealing, the nibs fit with an interference fit into the grooves

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2852784B9Pipe connection
Publication Date: 2019.12.11 SINGLE BUOY MOORINGS INC
  • EP2852784B9 patent drawingFigure 1
  • EP2852784B9 patent drawingFigure 2~5

AI summary

A pipeline includes a pair of pipe sections with ends (20, 22), connected together by threads, the pipe ends having axial and radial abutments lying beyond the ends of the thread. The abutments are located to stabilize a nib sealing arrangement and to enhance the capacity to resist bending while using a shorter thread length. The shorter threads (24, 28) enable pipe ends of smaller wall thicknesses to be used. At the abutments, each pipe end has a nib (40A, 40B) that is deflected to enter a groove as the pipe ends mate,