Flexible Multilayer Pipe Liners for Abrasive Slurry Service

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Solution Overview

Problem

Current CIPP technologies are inadequate for transporting gritty water-based slurries and high-temperature materials, as they lack sufficient abrasive and thermal resistance, leading to premature mechanical failures in pipes.

Innovation Solution

Flexible multilayer pipe liners composed of a fibrous layer saturated with a resin dispersion and a polyolefin backing layer, featuring a blend of ultra-high molecular weight ethylene-based polymers, polyethylene resins, thermoplastic polyolefin elastomers, and optionally fluoropolymers, providing enhanced abrasion resistance and thermal properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional CIPP technology is used, then the pipe rehabilitation process is simple and cost-effective, but the liner lacks sufficient abrasion resistance and thermal stability for transporting abrasive slurries at elevated temperatures

Engineering Contradiction:
Improveabrasion resistance and thermal stabilityVSAvoidcomposite structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies composite materials by combining a fibrous layer saturated with curable resin and a polyolefin backing layer made from blended polymers (ultra-high molecular weight polyethylene, polyethylene resin, and thermoplastic polyolefin elastomer). This composite structure provides both abrasion resistance and thermal stability while maintaining flexibility for CIPP installation, directly resolving the contradiction between reliability and complexity.

Inventive Principle:
Principle #40Composite materials

2Duration of action of stationary object

If conventional CIPP liners are used, then the installation process is straightforward, but the liners fail prematurely when exposed to abrasive particulate streams and high temperatures

Engineering Contradiction:
Improveservice life of pipe linerVSAvoidliner manufacturing complexity
Core Design Contradiction:
Duration of action of stationary objectVSEase of manufacture

Solution Approach 1:

The composite structure with polyolefin backing layer and fibrous reinforcement layer provides enhanced durability against abrasion and heat, extending service life. The use of thermoplastic polyolefin elastomer specifically contributes to both mechanical strength and resistance to thermal degradation, addressing the service life requirement while maintaining manufacturability through established CIPP processes.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes material parameters by selecting specific polymer blends with controlled molecular weights and densities. The ultra-high molecular weight polyethylene component provides exceptional wear resistance, while the thermoplastic polyolefin elastomer adds flexibility and toughness. These parameter optimizations enable the liner to withstand abrasive slurries and high temperatures without compromising ease of manufacture.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If standard polyolefin blends are used, then the material is processable and flexible, but it provides insufficient resistance to abrasive wear from gritty slurries

Engineering Contradiction:
Improveabrasion resistanceVSAvoidmaterial flexibility and processability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent optimizes material parameters by incorporating ultra-high molecular weight polyethylene with specific viscosity ranges (5-50 deciliters/gram) and controlling the molecular weight distribution of polyethylene components. These parameter changes enhance abrasion resistance while the thermoplastic polyolefin elastomer maintains flexibility and processability, allowing the material to be installed using standard CIPP methods.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The composite polyolefin blend combining three different polymer components creates synergistic effects where each component contributes specific properties: ultra-high molecular weight polyethylene for wear resistance, polyethylene resin for structural integrity, and thermoplastic polyolefin elastomer for flexibility. This composite approach achieves superior abrasion resistance without sacrificing ease of operation.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentUS11254107B2Abrasion resistant flexible composites and multilayer pipe liners for cured-in-place pipe
Publication Date: 2022.02.22 DOW GLOBAL TECHNOLOGIES LLC

AI summary

Embodiments of the present disclosure include composites and flexible multilayer pipe liners comprising a fibrous layer; and a polyolefin backing layer comprising a blend of: (a) an ultra-high molecular weight ethylene-based polymer having an intrinsic viscosity from 5 to 50 deciliters/gram, (b) a polyethylene resin comprising a first molecular weight ethylene-based polymer component and a second molecular weight ethylene-based polymer component, wherein the polyethylene resin has a density from 0.930 to 0.960 g/cc; (c) a thermoplastic polyolefin elastomer having a density of from 0.850 to 0.910 g/cc; and (d) optionally, a fluoropolymer.