Variable-Taper Tube Plug Assembly for Wide-Range High-Pressure Sealing
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Solution Overview
Problem
Existing expandable plug assemblies for heat exchangers face challenges in creating effective seals across a wide range of tube inner diameters while maintaining high pressure holding capabilities, as conventional plugs either accommodate multiple diameters poorly or high pressures inadequately due to limitations in pin length and taper angle.
Innovation Solution
A plug assembly with a pin featuring varying taper angles along its length, where the angle is steeper at the nose section and shallower at the end section, allowing for increased installation force at larger diameters and improved pressure ratings without requiring longer pins or increased installation force, enabling a high-pressure seal across a broader diameter range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a consistent relatively-steep conical pin angle is used to accommodate a large range of tube diameters, then the sealing diameter range is improved, but the pressure holding capability deteriorates due to reduced radial force
Solution Approach 1:
The pin is divided into multiple sections (nose section, intermediate section, end section) with different taper angles. The nose section has a steeper taper angle for initial engagement and diameter adaptation, while the end section has a shallower taper angle for maintaining high radial force and pressure holding capability. This local differentiation allows the single pin to achieve both wide diameter range accommodation and high pressure resistance.
2Strength
If a consistent relatively-shallow conical pin angle is used to maintain high pressure holding capability, then the pressure resistance is improved, but the expansion range to seal different tube diameters is limited
Solution Approach 1:
Different sections of the pin have optimized taper angles for different functions. The end section with shallower taper angle provides high radial force for pressure holding, while the nose section with steeper taper angle enables expansion across a wider diameter range. This local optimization resolves the contradiction between pressure resistance and diameter adaptability.
3Adaptability or versatility
If the pin length is increased to expand the ring to accommodate larger diameters, then the sealing diameter range is improved, but the device complexity and installation force requirements increase
Solution Approach 1:
Instead of uniformly increasing pin length, the invention varies the taper angle locally along the pin length. The steeper nose section achieves diameter expansion more efficiently, allowing the pin to accommodate large diameters without requiring excessive overall length. This reduces device complexity while maintaining wide sealing capability.
4Strength
If the installation force is increased to improve pressure ratings, then the pressure holding capability is improved, but the force required for installation increases
Solution Approach 1:
The shallower taper angle in the end section of the pin is specifically designed to transmit installation force more efficiently into radial compressive force on the ring. This local geometric optimization improves pressure ratings without requiring a proportional increase in overall installation force, as the force is more effectively converted into the desired radial compression.
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 variable angle pin design enhances pressure holding capabilities by up to 75% over conventional wide-range plugs while maintaining compatibility with a wide range of tube diameters, matching high-pressure plug performance without increased installation force or pin length.
Implementation Method 1
an elongated pin having a conical shape with a constant taper along its length which is slidably received within the ring for expanding the ring outwardly when the pin is pulled axially relative to the ring
Implementation Method 2
The inner surface of the ring and the outer surface of the pin are disposed in confronting relation and are slidable relative to one another
Implementation Method 3
the ring expands and compresses against an inner diameter wall of a tube thereby forming a metal-to-metal seal
Implementation Method 4
After a predetermined amount of outward pressure has been applied, the breakaway ruptures
Data Source
AI summary
A pin and ring-type plug assembly for plugging a heat exchanger tube to provide a leak resistant seal is provided. The plug assembly is designed such that it can be used to form a high-pressure seal relative to a wide of range of tube inner diameters. The angle of taper of the pin varies along a length of the pin such that the angle of taper is steepest at or adjacent a nose section of the pin and is shallowest at or adjacent an end section of the pin.