Dual-Durometer Stress Suppressor for Thin-Wall Hot Tapping
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Solution Overview
Problem
Existing hot tapping tools face challenges when dealing with thin-walled steel pipelines, as they can cause deformation or failure due to excessive force application, especially in pipes with wall thicknesses under 3.35 mm, leading to potential gas or liquid leaks from highly flammable and explosive materials.
Innovation Solution
A pipeline isolation tool with a dual-stage stress suppressor system, featuring an elastomeric element that redistributes forces axially and radially, reducing the stress gradient during insertion and use, comprising a primary suppressor that lengthens axially and a secondary suppressor that widens radially, designed to complement the pipe curvature and absorb stress without external actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mechanical force is applied to position the plugging tool through the T-fitting, then the tool can be inserted and sealed against the pipeline wall, but excessive force causes deformation or failure of thin-walled pipes
Solution Approach 1:
The stress suppressor is divided into multiple elastomeric elements with different durometers arranged in series. The first elastomeric element has a lower durometer to provide initial compliance and stress distribution, while the second element has a higher durometer to maintain structural integrity. This segmentation allows the system to handle both soft compliance and hard support functions separately, reducing stress concentration on thin-walled pipes during tool insertion.
2Strength
If the pipeline wall is thin (under 3.35 mm), then the pipe can handle pressure when installed, but the applied force from the plugging tool results in failure or deformation
Solution Approach 1:
The stress suppressor utilizes elastomeric elements with different durometers (hardness parameters) to change the mechanical properties of the suppressor system. The first element uses a softer durometer to absorb and distribute the high insertion forces, while the second element uses a harder durometer to maintain structural support. This parameter change in material hardness allows the system to protect thin-walled pipes during tool insertion while maintaining sufficient strength.
3Device complexity
If a single durometer elastomer is used in the stress suppressor, then the structure is simple, but it cannot effectively redistribute forces in both axial and radial directions
Solution Approach 1:
Different regions of the stress suppressor are assigned different durometer values to perform specialized functions. The first elastomeric element with lower durometer is positioned to handle axial compression and initial contact forces, while the second element with higher durometer handles radial forces and maintains structural geometry. This local quality differentiation allows each region to optimize its performance for specific force redistribution requirements.
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 significantly reduces the overall force applied to the pipeline wall, allowing safe servicing of previously unserviceable thin-walled pipes by distributing stress effectively, thereby preventing deformation and failure, and enabling the use of fittings that were previously avoided due to safety concerns.
Implementation Method 1
The suppressor includes an elastomeric element. The elastomeric element may be a dual durometer elastomeric element... suppressing stress experienced by the inner wall by compressing the elastomeric element against the inner wall
Data Source
AI summary
Embodiments of a plugging tool (10) of this disclosure a control bar head (20) and at least one sealing head (30, 40) pivotally connected to the control bar head, the control bar head including a stress suppressor (50) located at a lower end (25) of the control bar head, the stress suppressor including an elastomeric element (51). The stress suppressor can act as a dual-stage suppressor, there being a primary (first stage) and a secondary (second stage) stress suppressor or zone (50A, 50B). The primary stress suppressor has an arched-shaped lowermost end (58) located between a pair of spaced-apart feet (21) of the control bar head, the feet having lateral edges (23) and comprising the secondary stress suppressor. During rotation of the tool into the pipe, stress to the pipe is reduced in a range of 5X to 14X relative to a plugging tool without the stress suppressor.