Nested Seal Ring Assembly for Low-Friction Pipe Ball Joints

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Solution Overview

Problem

Existing ball and socket-type dynamic joints in pipe connections face challenges with high friction during assembly and sealing, particularly in industries like oil and gas production, where misaligned pipes require complex internal joint designs and seals that inhibit motion.

Innovation Solution

A pipe ball joint design featuring a casing with a spherical interior surface and annular groove, utilizing a seal assembly of nested chevron-shaped seal rings with tapered surfaces and a retainer to reduce friction and enhance sealing under pressure, allowing for axial compression and radial sealing engagement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a ball and socket-type dynamic joint is used to join misaligned pipes, then the joint can accommodate pipe movement and prevent over stressing, but the seal components exhibit high friction that inhibits the motion of the dynamic joint

Engineering Contradiction:
Improvejoint flexibilityVSAvoidmotion inhibition
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The seal assembly is divided into multiple nested seal rings (first seal ring, second seal ring, third seal ring) that can independently deform and slide relative to each other. This segmentation allows each ring to contribute to the sealing function while reducing overall friction during ball rotation, resolving the contradiction between maintaining joint flexibility and enabling smooth operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The seal rings are designed with dynamic characteristics, allowing them to deform elastically under pressure and slide relative to one another during ball rotation. The nested configuration enables the seals to adapt dynamically to the spherical interface geometry while maintaining low friction, thus preserving joint flexibility without inhibiting motion.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If traditional seal components are used in ball and socket joints, then the assembly is simpler, but the friction is high which inhibits the motion of the dynamic joint

Engineering Contradiction:
Improveassembly simplicityVSAvoidmotion inhibition
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The seal assembly employs a nested configuration where the first seal ring, second seal ring, and third seal ring are arranged concentrically within each other. This nested structure achieves low-friction operation through multiple sliding interfaces while maintaining a relatively compact and simple overall assembly, balancing device complexity with operational ease.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Adaptability or versatility

If misaligned pipes are connected using ball and socket-type dynamic joints, then pipe movement is accommodated, but the internal joint design and seal design become complicated

Engineering Contradiction:
Improvemisalignment accommodationVSAvoidseal design complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The seal rings are designed with non-uniform cross-sectional geometries, where different portions of each ring have different thicknesses and curvature radii. This local quality variation optimizes the sealing contact at the spherical interface while simplifying the overall seal assembly design, enabling misalignment accommodation without excessive complexity.

Inventive Principle:
Principle #3Local quality

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 design achieves reduced friction during assembly and improved sealing performance under pressure, maintaining joint flexibility and effectiveness across varying pressure conditions.

Implementation Method 1

The seal assembly includes a plurality of nested seal rings that are chevron-shaped in cross section. The concave face includes a recessed surface that can include a pair of tapered surfaces that terminate at a floor surface. The convex face includes a protruding surface that can include a pair of tapered surfaces that terminate at a peak surface.

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

The present disclosure provides a ball pipe joint design with reduced friction during assembly and improved sealing under pressure.

Methodology Applied
Scientific EffectFriction reduction: Lubrication

Implementation Method 3

A retainer is secured to the casing encompassing the ball pipe, and is disposed against an axial end of the seal assembly. The design achieves reduced friction during assembly and improved sealing performance under pressure.

Methodology Applied
Scientific EffectContact pressure: Pressure Increase

Data Source

PatentEP4073412B1Ball joint seal
Publication Date: 2024.03.13 FREUDENBERG OIL & GAS LLC
  • EP4073412B1 patent drawingFigure 1
  • EP4073412B1 patent drawingFigure 2

AI summary

The pipe ball joint includes a casing having a socket portion with a substantially spherical interior surface and a first pipe segment extending from the socket portion. The socket portion has an annular groove disposed adjacent the partially spherical interior surface. A ball pipe section includes a ball segment received in the socket portion of the casing and a second pipe segment extending from the ball segment. A seal assembly is received in the annular groove of the casing and is disposed against the ball segment of the ball pipe section. The seal assembly includes a plurality of nested seal rings that each include a concave face and a convex face.