Weld Test Plug Seal Expansion for High-Pressure Vessel Removal
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Solution Overview
Problem
Existing weld test plugs face challenges in effectively sealing and unsealing under high pressure conditions, particularly in vessels with varying internal diameters and restrictions, leading to potential deformation and difficulty in removal, which can necessitate disassembly or cutting open the vessel.
Innovation Solution
A weld test plug with an actuator rod, annular seal, and axial stop, where the actuator rod actuates the axial stop to radially expand the annular seal against the vessel's inner surface, using frustoconical wedges to limit expansion and ensure a secure, reversible seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the annular seal is expanded radially to seal against the vessel inner surface, then sealing reliability is improved, but the seal may deform and become difficult to remove
Solution Approach 1:
The seal expansion mechanism is made dynamic and reversible through the actuator rod and frustoconical wedge system. The seal can be expanded radially when needed for testing and then contracted for removal, transforming a static sealing solution into a dynamic one that adapts to operational requirements.
Solution Approach 2:
The sealing function is segmented into expansion and contraction phases controlled by the actuator rod. The frustoconical wedge structure segments the force application, allowing controlled radial expansion during insertion and reversal for removal, enabling the seal to perform opposite functions in sequence.
2Stress or pressure
If the seal is expanded to withstand high pressure, then pressure resistance is improved, but the vessel may require disassembly or cutting for removal
Solution Approach 1:
The sealing system employs dynamic expansion and contraction capability through the actuator mechanism. The seal can be expanded to withstand high pressure during testing and then contracted to enable easy removal without vessel disassembly, eliminating the need for cutting or complex disassembly procedures.
Solution Approach 2:
The actuator rod serves as an intermediary mechanism between the operator and the seal. It transmits force to expand the seal for pressure resistance and then reverses to contract the seal for removal, mediating between the high pressure requirement and the ease of removal requirement.
3Reliability
If the seal is expanded radially to ensure fluid-tight sealing, then sealing effectiveness is improved, but removal time and cost increase
Solution Approach 1:
The seal system is designed with dynamic reversibility, allowing rapid transition from expanded sealed state to contracted removal state. The actuator rod mechanism enables quick contraction of the seal after testing, significantly reducing removal time and associated costs while maintaining effective sealing during the test phase.
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 solution provides a reliable, fluid-tight seal that withstands high pressures, minimizes safety risks, and allows easy removal by preventing seal deformation, thus reducing time and cost in hydrostatic testing.
Implementation Method 1
The first axial portion forms a wedge that is tapered with decreasing radius in a direction toward the annular seal. The first axial portion is frustoconical in shape.
Implementation Method 2
The annular seal comprises elastomeric material. The annular seal is mounted such that during actuation the first end abuts the axial stop.
Implementation Method 3
The axial stop comprises collet fingers. The collet fingers are biased to radially contract during resetting of the weld test plug.
Data Source
Figure 1
Figure 2~3
Figure 4~4C
AI summary
A weld test plug has a flange; an actuator rod mounted to the flange, the actuator rod having: a part expander; an annular seal; and an axial stop; in which the actuator rod is connected to, during use, cause the part expander to actuate: the axial stop to move in a radially outward direction relative to the actuator rod; and the annular seal to radially expand and abut the axial stop. A method includes inserting an actuator rod into an open end of a vessel, the actuator rod carrying an annular seal, and an axial stop; sealing the open end of the vessel around the actuator rod; operating the actuator rod to actuate: the axial stop to move in a radially outward direction relative to the actuator rod; and the annular seal to radially expand to abut the axial stop and seal against an inner circumferential surface of the vessel.