Fiber-Reinforced Multilayer Tube for Thin-Wall Pressure Resistance
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Solution Overview
Problem
Existing plastic multi-layer pipes struggle to withstand internal pressure effectively with minimal wall thickness, as conventional designs lack optimal reinforcement for creep resistance.
Innovation Solution
A three-layer pipe design featuring a fiber-reinforced middle layer with fibers aligned between 1° and 60° to the longitudinal axis, combined with a single-layered inner and outer polypropylene structure, enhances creep pressure behavior by concentrating fibers in a spiral reinforcing strand and intermediate strand configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the wall thickness of plastic multi-layer pipes is reduced to minimize material usage and cost, then the internal pressure resistance and creep strength deteriorate
Solution Approach 1:
The patent applies composite materials by embedding glass fibers in the middle layer of the three-layer pipe structure. The middle layer consists of a plastic matrix (polypropylene or polyethylene) reinforced with glass fibers having a fiber volume fraction of 20-60%. This composite structure in the middle layer provides enhanced creep resistance and internal pressure strength, allowing the overall wall thickness to be reduced while maintaining structural integrity under internal pressure.
Solution Approach 2:
The patent applies local quality by concentrating the fiber reinforcement specifically in the middle layer, while the inner and outer layers remain as plain plastic without fibers. The inner layer (10-40% of wall thickness) and outer layer (40-80% of wall thickness) provide protective functions, while the middle layer (30-70% of wall thickness) provides structural reinforcement. This localized fiber placement optimizes material distribution, providing maximum pressure resistance where needed while minimizing overall material usage.
2Strength
If fibers are uniformly distributed throughout the pipe wall to maximize reinforcement, then material consumption and production time increase
Solution Approach 1:
The patent applies local quality by concentrating the fiber reinforcement specifically in the middle layer, while the inner and outer layers remain as plain plastic without fibers. The inner layer (10-40% of wall thickness) and outer layer (40-80% of wall thickness) provide protective functions, while the middle layer (30-70% of wall thickness) provides structural reinforcement. This localized fiber placement optimizes material distribution, providing maximum pressure resistance where needed while minimizing overall material usage.
Solution Approach 2:
The patent applies segmentation by dividing the pipe wall into three distinct layers with different functions: the inner layer for fluid contact and protection, the middle layer for structural reinforcement with fibers, and the outer layer for environmental protection. This segmentation allows the fiber reinforcement to be concentrated only where structurally necessary (middle layer), rather than uniformly distributed throughout the entire wall, thereby reducing total fiber consumption and simplifying the extrusion process.
Data Source
Figure 1~2
AI summary
The invention relates to an extruded multilayer tube, hereinafter referred to as tube (1), comprising an inner layer (5) made of plastic, in particular polypropylene, an outer layer (7) made of plastic, in particular polypropylene, a middle layer (6) between the inner layer (5) and the outer layer (7) with a matrix made of plastic and a reinforcement made of fibers (8), wherein the fibers (8) in the middle layer (6) are aligned with a fiber angle (α) to the longitudinal axis (2) of the tube (1), and wherein the fiber angle (α) lies between a lower limit of 1° and an upper limit of 60°.