Self-Energizing Isolation Plug Seal for Variable Pipe Walls
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Solution Overview
Problem
Existing pipeline isolation tools face challenges in effectively isolating pressurized pipes with varying wall thicknesses and in maintaining sealing engagement over a wide range of pipe sizes, often requiring complex setups and additional tools for debris removal.
Innovation Solution
A pipeline isolation tool utilizing a dual durometer seal with a softer outer surface and a harder core, actuated by a hydraulic piston-and-cylinder arrangement, and supported by metal segments with unique profiles to expand radially, along with a sweep mechanism to clear debris, allowing for self-energizing sealing and efficient pressure retention across a range of pipe sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional sealing mechanism is used, then the structure is simple, but it cannot effectively isolate pressurized pipes with varying wall thicknesses
Solution Approach 1:
The seal transitions from a static configuration to a dynamic expanding structure. The seal is initially in an unset state during insertion, then expands radially to a set state to engage the pipe wall. This dynamic transformation allows the same seal to adapt to different pipe wall thicknesses while maintaining a relatively simple overall structure.
Solution Approach 2:
The seal's radial dimension changes from an unset diameter to a set diameter (1.13 to 1.30 times larger). This parameter change enables the seal to accommodate varying pipe wall thicknesses. The dual durometer seal's hardness distribution also changes during expansion, with the softer outer surface deforming to conform to the pipe wall geometry.
2Reliability
If the seal is expanded radially to engage the pipe wall, then sealing capability is improved, but the risk of extrusion increases
Solution Approach 1:
The seal employs dual durometer construction with different hardness values in different regions. The softer outer surface (first durometer) contacts the pipe wall and deforms to conform to surface irregularities, while the harder core material (second durometer) provides structural support and resists extrusion. This local quality differentiation simultaneously improves sealing reliability and prevents extrusion.
3Strength
If metal support segments fully enclose the seal, then support is maximized, but the tool cannot be inserted through the pipe
Solution Approach 1:
The support structure is divided into multiple separate metal segments arranged circumferentially around the seal. These segments are spaced apart rather than forming a complete enclosure, allowing the seal to expand radially while maintaining access for insertion. The segments provide distributed support strength while the gaps enable the tool to pass through the pipe.
4Force
If axial compression is applied to expand the seal radially, then sealing force is improved, but axial misalignment becomes more critical
Solution Approach 1:
The seal is pre-compressed axially by the piston before radial expansion occurs. This preliminary axial compression stores elastic energy in the seal material and pre-loads the sealing surfaces. When the seal expands radially, this pre-compression ensures immediate engagement with the pipe wall, compensating for minor axial misalignments and reducing the criticality of precise positioning.
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 tool provides optimized sealing capabilities, supports expansion over a wide range of pipe sizes, maintains effective sealing despite axial misalignment, and eliminates the need for external debris removal tools by using a sweep mechanism, enhancing operational efficiency and pressure retention.
Implementation Method 1
an expandable seal (30) configured to sealably engage an opposing pipe wall and expand from an unset position to a set position
Implementation Method 2
an hydraulically actuated piston-and-cylinder arrangement compresses the seal axially, thereby expanding the seal radially outward
Implementation Method 3
making the seal self-energizing
Data Source
AI summary
A pipeline isolation tool [10] and method of its use includes a plugging head [20] having a seal [30] to sealably engage a pipe wall; a fluid-activated cylinder [64] located on one side of the seal and moveable in an axial direction; metal support segments [40] located on another side of the seal and moveable in a transverse direction radially outward and inward; the metal segments including a concave portion [45], a portion [35] of the seal residing within the concave portion when unset and set. When in a seal unset position a portion [33] of the seal is covered by adjacent metal support segments of the plurality. When in a seal set position the portion of the seal is exposed between the adjacent metal support segments. The seal is self-energizing, its actuating force being in a same direction as a force from isolation pressure.