Multilayer Plastic Hose for Drinking Water
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Solution Overview
Problem
Current multilayer flexible pipes for fluid transport, particularly for drinking water, face limitations in diameter range and high manufacturing costs due to the use of fluorinated thermoplastics, with single-material pipes having limited pressure resistance and availability only in diameters less than 25mm, and existing multilayer pipes with elastomer components not suitable for PVC outer layers.
Innovation Solution
A flexible plastic pipe with a multilayer structure comprising a PVC outer layer, a thermoplastic polyurethane bonding layer, and a fluorinated thermoplastic resin inner layer, allowing for coextrusion and production in a wide range of diameters with enhanced chemical resistance and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If single-material fluorinated thermoplastic pipes are used, then chemical resistance is improved, but manufacturing cost increases and diameter is limited to less than 25mm
Solution Approach 1:
The pipe is divided into multiple layers with different materials: an inner layer of fluorinated thermoplastic for chemical resistance, a middle layer of PVC for structural support and cost-effectiveness, and an outer layer for protection. This segmentation allows each layer to perform its specific function optimally while reducing overall manufacturing cost compared to single-material construction.
Solution Approach 2:
The invention uses composite material construction combining fluorinated thermoplastic, PVC, and other materials in a multilayer structure. This allows the pipe to achieve the chemical resistance of fluorinated materials while incorporating the cost advantages and mechanical properties of PVC, resolving the contradiction between chemical resistance and manufacturing cost.
2Reliability
If single-material fluorinated thermoplastic pipes are used, then chemical resistance is improved, but available diameter range is limited to less than 25mm
Solution Approach 1:
By segmenting the pipe into multiple layers with different material properties, the invention enables production of pipes in various diameter ranges. The multilayer structure can be manufactured using different extrusion techniques suitable for various diameters, from small to large sizes, overcoming the 25mm limitation of single-material pipes.
Solution Approach 2:
The composite multilayer construction allows the pipe to maintain chemical resistance while being manufactured in a wide range of diameters. The different material layers can be extruded and assembled using techniques that accommodate various diameter requirements, expanding adaptability beyond the limitations of single-material construction.
3Strength
If braiding-type reinforcement is added to single-material tubes, then pressure and temperature resistance is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The reinforcement function is segmented into a dedicated middle layer of PVC with specific mechanical properties, separate from the inner chemical-resistant layer and outer protective layer. This segmentation integrates pressure resistance into the multilayer structure itself, eliminating the need for separate braiding reinforcement and reducing manufacturing complexity.
Solution Approach 2:
The multilayer composite structure incorporates a middle layer designed for mechanical strength and pressure resistance, integrating the reinforcement function into the pipe wall itself. This eliminates the need for additional braiding reinforcement processes, reducing manufacturing complexity while maintaining high pressure and temperature resistance.
4Ease of operation
If multilayer pipes with elastomer components are used, then flexibility is improved, but compatibility with PVC outer layers is lost due to temperature limitations
Solution Approach 1:
The invention changes the material parameters by selecting a PVC compound with a degradation temperature above the melting point of the fluorinated thermoplastic. This parameter change enables the inner fluorinated layer to be extruded over the PVC middle layer without degradation, achieving both flexibility from the multilayer construction and compatibility with PVC outer layers.
Solution Approach 2:
By adjusting the thermal parameters of the PVC material (selecting compounds with higher degradation temperatures), the invention resolves the incompatibility issue. The modified PVC can withstand the extrusion process temperatures required for the fluorinated thermoplastic layer, enabling successful multilayer construction with both flexibility and material compatibility.
Data Source
AI summary
The plastic flexible hose (1) comprises three layers including an intermediate layer (4) comprising polyvinyl chloride, a bonding layer (5) made of thermoplastic polyurethane and an inner layer (6) made of a fluoride thermoplastic resin layer having a thickness of 150 mu m, a braided, woven or knitted reinforcing layer (3), and a covering layer (2). The inner layer has a melting temperature less than the melting temperature of polyvinyl chloride degradation. The bonding layer has a thickness of 30-300 mu m. The intermediate layers, the bonding layer and the internal layer are co-extruded.