Expansion Compensator Metal Conduit Plastic Liner
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Solution Overview
Problem
Thermoplastic pipes used in piping systems are prone to thermal expansion and contraction, leading to axial forces that can cause leaks and system failure, especially in high-rise buildings where mechanical constraints exacerbate stress, making repairs time-consuming and costly.
Innovation Solution
An expansion compensator comprising an outer metal conduit and an inner plastic liner, where the metal conduit supports the plastic liner and absorbs thermal stresses, reducing the likelihood of cracking and leaks by allowing for axial expansion and contraction, and featuring connectors that secure the components together to form a unitary body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plastic pipes are mounted vertically in high rise buildings, then water can be transported between floors, but mechanical constraints from transverse pipe attachments create buckling stress that exceeds pipe strength
Solution Approach 1:
The outer metal conduit provides high buckling resistance to withstand the mechanical constraints imposed by transverse pipe attachments in vertical installations, while the inner plastic liner maintains compatibility with the thermoplastic piping system. This enables safe vertical water transport in high rise buildings.
Solution Approach 2:
The expansion compensator changes the mechanical parameters of the piping system by introducing a component with higher stiffness and buckling resistance (the metal conduit) while maintaining the fluid transport function through the inner plastic liner.
2Ease of manufacture
If the piping system is installed and walls are finished, then the system is complete, but accessing the system to repair leaks becomes time consuming and expensive
Solution Approach 1:
The expansion compensator is designed as a replaceable module that can be accessed and replaced without demolishing finished walls. The connectors allow the compensator to be installed and removed as a discrete unit, facilitating easy repair of leaks while maintaining installation completeness.
3Strength
If connectors are used to join expansion compensator components, then the components are securely attached, but the connectors themselves may be subject to thermal stress
Solution Approach 1:
The connectors serve as intermediary elements that join the inner plastic liner to the outer metal conduit. They are designed to accommodate thermal stress through flexible attachment methods (such as overmolding or mechanical interlocking) that allow for expansion and contraction while maintaining secure attachment of the components.
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 expansion compensator effectively reduces the stress on thermoplastic pipes due to thermal cycling, preventing leaks and enhancing the reliability of piping systems, allowing for the use of plastic piping in long runs, including high-rise buildings, by absorbing axial forces and maintaining the static position of fittings.
Implementation Method 1
Thermoplastic pipes (such as polyvinyl chloride (PVC) and/or chlorinated polyvinyl chloride (CPVC) pipes) may be subject to thermal expansion and/or contraction after installation
Implementation Method 2
a length of a thermoplastic pipe used for conveying fluid at an elevated temperature (e.g. hot water) may be subject to axial expansion and/or contraction based on the relative temperature of the fluid being conveyed
Implementation Method 3
the water in the pipe will cool as heat is dissipated to the ambient surrounding structure. This heating and cooling will cause the pipe to expand and contract axially
Data Source
AI summary
An expansion compensator having an elongate metal conduit with first and second spaced apart ends and an expansion/contraction section, an inner plastic liner positioned interior of the elongate metal conduit and having an expansion/contraction section and an interior volume extending from the first end to the second end, and first and second connectors provided at the first and second ends, respectively, of the elongate metal conduit and the inner plastic liner, each connector having a first portion secured to the outer surface of the elongate metal conduit, a second portion secured to the inner surface of the inner plastic liner, and an opening in fluid communication with the interior volume of the inner plastic liner.