Pressure-Responsive Pigging Element for Wear-Stable Pipeline Sealing
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Solution Overview
Problem
Pipeline pigging elements experience significant wear and loss of sealing capability due to abrasion, leading to reduced effectiveness over short distances, especially in dry gas pipelines, resulting in decreased fluid flow and potential line choking by contaminants.
Innovation Solution
A hollow body pigging element with varying section moduli and internal structural hoops allows for axial and radial deformation in response to pressure, maintaining sealing forces and flexibility as it wears, eliminating the need for additional fluids or pumps and enabling longer transit distances with sustained sealing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional solid pigging elements are used, then initial sealing capability is achieved, but sealing capability degrades rapidly due to abrasion over distance
Solution Approach 1:
The pigging element changes its physical state from solid to hollow, allowing it to deform and adapt its sealing surface area as it travels through the pipeline. This parameter change enables the element to maintain sealing capability despite material loss from abrasion, as the hollow structure can collapse and reform to maintain contact with the pipe wall.
Solution Approach 2:
The pigging element is designed with dynamic characteristics, allowing it to deform axially and radially in response to pressure differentials and wear. This dynamic behavior enables the element to self-adjust its geometry to maintain effective sealing contact with the pipe wall throughout its transit distance.
2Manufacturing precision
If pigging elements are made rigid for structural stability, then manufacturing precision is improved, but adaptability to wear and deformation is reduced
Solution Approach 1:
The pigging element employs a hollow shell structure that combines geometric precision in its initial state with flexibility during operation. The hollow construction allows the shell to deform and adapt to wear while maintaining the overall geometric integrity needed for effective sealing and structural stability.
3Reliability
If additional inflation means are added to maintain sealing, then sealing capability is improved, but device complexity increases
Solution Approach 1:
The hollow pigging element utilizes the natural pressure differential created by the pipeline flow to inflate and maintain its sealing shape without requiring external inflation systems. The element self-regulates its geometry through pressure-driven deformation, eliminating the need for complex mechanical or pneumatic inflation mechanisms.
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 pigging element maintains 85% to 99% of its original sealing capability over extended pipeline transit, resisting wear and maintaining effective sealing forces without additional inflation means, ensuring consistent performance and reduced material loss.
Implementation Method 1
the pigging element is deformable axially and radially in response to pressure differential
Implementation Method 2
The hollow body includes internal structure (ribs or hoops) that allows the shape of the body to be modified by pressure
Implementation Method 3
The urethane materials typically used for the pigging elements are very elastic in their formation, allowing the material to act much like a spring
Data Source
AI summary
A pipeline pigging element (10) that changes its size in an axial and a radial direction as a function of applied pipeline pressure. The pigging element includes at least two circumferential zones (13, 15) having different section modulus than one another, each of the zones changing at different rates from one another between an uninflated and an inflated state at the applied pipeline pressure. The pigging element reacts to changes in pipe geometry, having a first length and a first diameter at a first applied pipeline pressure and a second length and a second diameter different than the first at a second applied pipeline pressure. As the pigging element wears, it becomes easier to inflate at the applied pressure and sealing contact with the pipe wall remains substantially unaffected. No onboard pumps or fluid circuits are required to inflate the pigging element.