Double-Ended Flexible Pipe Joint With Stacked Elastomeric Flex Elements

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Solution Overview

Problem

Double-ended flexible pipe joints face challenges in handling high fluid pressure and peak axial loads, leading to reduced usable life and inefficient use of flex elements, as existing designs subject primary flex elements to both axial loads and fluid pressure, which degrades their performance and longevity.

Innovation Solution

Incorporating secondary annular elastomeric flex elements within the inner housing to contain fluid pressure, thereby eliminating pressure on primary flex elements, which are designed to handle axial, angular displacement, and torsion loads, while secondary flex elements manage fluid pressure, allowing for a more compact and lightweight design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If primary flex elements are used to handle both axial loads and fluid pressure, then the structure remains simple, but the usable life of the flex elements is reduced due to degradation from combined loading

Engineering Contradiction:
Improvestructure simplicityVSAvoidusable life of flex elements
Core Design Contradiction:
Device complexityVSDuration of action of moving object

Solution Approach 1:

The patent divides the flex element system into two separate functional components: primary flex elements that handle axial loads and secondary flex elements that contain fluid pressure. This segmentation allows each component to be optimized for its specific function, preventing the degradation that occurs when a single element must handle combined loading, thereby extending the usable life of the primary flex elements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts the fluid pressure containment function from the primary flex elements and assigns it to separate secondary flex elements. By removing the harmful fluid pressure exposure from the primary elements, they can focus solely on bearing axial loads without degradation from combined stress, thus extending their service life.

Inventive Principle:
Principle #2Taking out (Extraction)

2Duration of action of moving object

If secondary flex elements are added to contain fluid pressure separately, then the lifetime of primary flex elements is extended, but the device complexity increases

Engineering Contradiction:
Improvelifetime of primary flex elementsVSAvoidnumber of flex elements
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The secondary flex elements serve multiple functions: they contain fluid pressure, provide a sealing mechanism, and protect the primary flex elements from pressure exposure. This multi-functionality justifies the added complexity by delivering multiple benefits from a single component addition.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The secondary flex elements act as a protective barrier that cushions the primary flex elements from the harmful effects of fluid pressure before the pressure can degrade the primary elements. This beforehand protection extends the lifetime of the primary flex elements by preventing pressure-induced degradation.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Stress or pressure

If two flex elements are used in a common housing with one carrying tensile load and the other providing sealing, then pressure from production fluid on each flex element is reduced, but the design requires pre-compression which reduces usable life

Engineering Contradiction:
Improvepressure on flex elementsVSAvoidusable life
Core Design Contradiction:
Stress or pressureVSDuration of action of moving object

Solution Approach 1:

The patent applies local quality by giving each flex element a specific specialized function: primary elements are optimized for load-bearing with appropriate material properties and geometric characteristics, while secondary elements are optimized for sealing with different material properties. This localized optimization allows each element to perform its specific function efficiently without the compromises required by general-purpose designs.

Inventive Principle:
Principle #3Local quality

4Strength

If the size of flex elements is increased to handle higher loads, then load-bearing capacity is improved, but the weight and manufacturing costs increase

Engineering Contradiction:
Improveload-bearing capacityVSAvoidweight of flex element
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

By segmenting the load-bearing and pressure-containing functions into separate elements, each element can be sized and designed for its specific purpose. The primary flex elements can be optimized for axial load bearing without needing to be oversized to accommodate pressure containment, thereby reducing weight while maintaining load-bearing capacity.

Inventive Principle:
Principle #1Segmentation

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 extends the lifetime of primary flex elements by reducing their exposure to fluid pressure, enhances load-bearing capacity, and maintains a compact size, reducing weight and manufacturing costs while resisting peak axial compressive loads.

Implementation Method 1

a first annular elastomeric flex element for mounting the first extension pipe to the housing, and a second annular elastomeric flex element for mounting the second extension pipe to the housing... capable of providing a free angular displacement of about ± 15 degrees or more while supporting an axial tension proportional to the size of the flex element

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2318746B1Double-ended flexible pipe joint having stacked co-axial primary and secondary annular elastomeric flex elements
Publication Date: 2013.02.13 OIL STATES INDUSTRIES INC
  • EP2318746B1 patent drawingFigure 1
  • EP2318746B1 patent drawingFigure 2
  • EP2318746B1 patent drawingFigure 3

AI summary

A double-ended flexible pipe joint (26) has first and second extension pipes (51, 52) extending from opposite ends of an outer housing (50), and first and second primary annular elastomeric flex elements (71, 74) mounting the first and second extension pipes (51, 52) to the outer housing (50). An inner housing (80) is disposed in the outer housing (50), and first and second secondary annular elastomeric flex elements (81, 82) disposed in the inner housing (80) mount the first and second extension pipes (51, 52) to the inner housing (80). Tension upon the first and second extension pipes (51, 52) places each of the first and second primary flex elements (71, 74) and each of the first and second secondary flex elements (81, 82) in compression. The first and second secondary flex elements (81, 82) contain fluid pressure within the first and second extension pipes (51, 52) so that the first and second primary flex elements (71, 74) are not subjected to the fluid pressure within the extension pipes (51, 52).