Braided PEX Pipe Reinforcement for High Pressure Sprinkler Systems
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Solution Overview
Problem
Conventional PEX pipes have insufficient short-term burst pressure and long-term hydrostatic strength for high-pressure and high-temperature applications, such as fire sprinkler systems, oil field recovery, and natural gas systems, and are inflexible, making them unsuitable for applications requiring higher temperature/pressure tolerances and prone to installation issues with rigid CPVC pipes.
Innovation Solution
A flexible PEX pipe with a braided structure, manufactured using the Engel Method, which provides a reinforcing outer PE jacket capable of withstanding high temperatures and pressures, allowing for mechanical fitting systems instead of glue and solvents, and maintaining flexibility without increasing pipe thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional PEX pipe is used, then manufacturing simplicity is maintained, but burst pressure and hydrostatic strength are insufficient for high-pressure applications
Solution Approach 1:
The patent applies composite materials by combining PEX pipe with an external braid reinforcement layer. The braid, made of high-strength material, is wrapped around the PEX pipe to create a composite structure that significantly enhances burst pressure and hydrostatic strength while maintaining the flexibility and installation advantages of PEX pipe. This composite approach allows the pipe to meet high-pressure application requirements without compromising the base PEX material's beneficial properties.
2Strength
If pipe thickness is increased to improve strength, then burst pressure increases, but flexibility and ease of installation are reduced
Solution Approach 1:
The patent applies segmentation by separating the strength-providing function from the flexibility-providing function. The PEX pipe material maintains flexibility and ease of installation, while the external braid reinforcement layer provides the additional strength and burst pressure capability. This functional segmentation allows each component to optimize its specific role without compromising the other, enabling the pipe to be both strong and flexible.
3Productivity
If mechanical fitting systems are used, then installation time and costs are reduced, but compatibility with reinforced pipe structure must be ensured
Solution Approach 1:
The patent applies local quality by ensuring that the pipe end regions maintain compatibility with standard PEX pipe characteristics. The braid reinforcement is applied in a manner that allows mechanical fittings to be properly installed at the pipe ends, preserving the ease of mechanical connection while the reinforced body provides the necessary strength. This localized approach to quality ensures fitting compatibility without compromising the overall reinforcement effectiveness.
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 braided PEX pipe achieves short-term burst ratings exceeding 1000 psi and long-term hydrostatic strength of 175 psi at 120° F., meeting NFPA standards, while reducing installation time and costs by minimizing fittings and potential leaks, and accommodating curved installations.
Implementation Method 1
a reinforcing structure surrounding the inner layer. The reinforcing structure can be coupled to the inner layer without being embedded in another material
Implementation Method 2
The Engel ('peroxide') Method performs 'hot cross-linking' because the cross-linking occurs during passage of melted and peroxide-infused HDPE under high pressure through a heated die
Implementation Method 3
The Engel ('peroxide') Method performs 'hot cross-linking' because the cross-linking occurs during passage of melted and peroxide-infused HDPE under high pressure through a heated die
Data Source
AI summary
A flexible tubing having a PEX inner core is surrounded by a reinforcing structure, such as a braid. The reinforced flexible tubing meets NFPA Standards for the Installation of Sprinler Systems (13/13R/13D) in both residential and commercial buildings. The reinforced flexible tubing is suitable for a variety of other high temperature/high pressure applications. The tube's flexible characteristics facilitate its installation at a greatly reduced cost, especially in retrofitting existing structures. An adhesive can be used to improve the overall strength and stability of the reinforcing structure surrounding the PEX core. Optionally, a protective outer layer can be applied over the reinforcing structure.