Removable Pipeline Plug With Frictional Slip Assembly
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Solution Overview
Problem
Conventional pipeline plugs, such as inflatable bags and cylindrical plugs, are ineffective for high-pressure applications and often damage the pipe during removal, while packer tools are complex and not removable without damage.
Innovation Solution
A pipeline plug with a seal assembly and slip assembly that can be moved between engaged and disengaged positions, allowing it to be inserted through a pipe end opening, sealingly engage the internal wall, and be removed without damage by reversing the assembly's positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an inflatable bag plug is used to block pipeline flow, then the plug can be easily inserted and positioned, but it becomes ineffective at high pressures and may be pushed through the pipe
Solution Approach 1:
The patent replaces the inflatable bag mechanical system with a slip assembly that uses friction-based mechanical engagement. The slips expand radially to grip the pipe wall, providing a mechanical interlock that resists high-pressure forces without relying on inflation pressure alone.
Solution Approach 2:
The plug combines multiple materials and mechanisms: the seal assembly with elastomeric seals for sealing, the slip assembly with friction surfaces for mechanical engagement, and the plug body structure. This composite approach integrates sealing functionality with mechanical retention to handle high-pressure conditions.
2Reliability
If a cylindrical plug with welded fitting is used to block pipeline flow, then the plug can be retained securely, but it requires drilling a hole in the pipe which must be sealed when the plug is removed
Solution Approach 1:
The invention extracts the retention mechanism from the pipe structure itself. Instead of welding a fitting to the pipe, the slip assembly provides retention through frictional engagement with the existing pipe interior surface, eliminating the need for pipe modification.
Solution Approach 2:
The slip assembly acts as an intermediary between the plug and the pipe wall. It transfers and distributes the retention forces through frictional contact across the pipe interior surface, providing secure retention without direct mechanical attachment to the pipe.
3Reliability
If packer tools are used to isolate zones in a well, then the seals can effectively isolate zones, but the tools are complex and cannot be removed without permanent damage
Solution Approach 1:
The plug is segmented into distinct functional assemblies: the seal assembly for sealing, the slip assembly for retention, and the plug body for structural support. This segmentation allows each component to be optimized independently and simplifies the overall tool design compared to integrated packer tools.
Solution Approach 2:
The plug is designed as a recoverable tool rather than a disposable one. The slip assembly can be contracted to release the grip on the pipe wall, allowing the entire plug to be retrieved and reused, unlike packer tools that require drilling through for removal.
4Reliability
If the slip assembly is expanded to frictionally engage the pipe wall, then axial movement of the plug is prevented, but the plug cannot be removed without damaging the tool
Solution Approach 1:
The slip assembly is designed with dynamic characteristics, allowing it to transition between expanded and contracted states. The grooves in the slips enable radial expansion for engagement and contraction for release, providing dynamic adaptability for both installation and removal operations.
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 plug effectively seals high-pressure pipelines, allowing for the repair or replacement of valves without damaging the pipeline or plug, and can be reused multiple times.
Implementation Method 1
the seal assembly... sealingly engage the internal wall of the pipe to prevent fluid from flowing past the pipeline plug
Implementation Method 2
the slip assembly moves to the expanded position, it preferably frictionally engages the internal wall of the pipe to prevent axial movement of the pipeline plug within the pipe
Implementation Method 3
The outer surface is movable from a retracted position to an expanded position... when the seal assembly moves from the disengaged position to the engaged position
Implementation Method 4
If pressure of fluid within the pipe and the force exerted by the fluid on the pressure engaging surface increases, the force by which the outer surface of the slip assembly frictionally engages the internal wall of the pipe also preferably increases
Data Source
AI summary
A pipeline plug having a seal assembly and a slip assembly coupled to the seal assembly. The slip assembly moves from a retracted position to an expanded position when the seal assembly moves from a disengaged position to an engaged position. The slip assembly frictionally engages the internal wall of a pipe when in the expanded position. The force exerted on the pipeline plug by fluid within the pipe increases the force by which the slip assembly engages the internal wall of the pipe. The plug is removable from the pipe without damaging the plug by moving the seal assembly back to the disengaged position. A method of sealing a pipeline using the pipeline plug.