CPVC-Metal Composite Pipe Bonding for Heat and Delamination Resistance

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Solution Overview

Problem

Current composite pipes lack the balance of properties between metal and plastic pipes, particularly in terms of impact resistance, temperature resistance, and de-lamination resistance, which leads to issues such as thermal expansion, buckling, and leaks in piping systems, especially under varying temperature conditions.

Innovation Solution

A CPVC multilayer composite pipe with a metal interlayer and optimized adhesive bonding process, including continuous temperature monitoring and external hot air blower setup, to enhance bonding between CPVC layers and the metal interlayer, providing improved temperature and de-lamination resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If composite pipes are made with adhesive bonding between layers, then manufacturing flexibility and ease of installation are improved, but de-lamination resistance and structural integrity deteriorate under elevated temperature conditions

Engineering Contradiction:
Improveease of installationVSAvoidde-lamination resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the bonding mechanism from chemical adhesive bonding to physical mechanical interlocking. The recessed groove geometry and expanded anchor features create a mechanical lock that prevents layer separation. This parameter change from chemical to mechanical bonding maintains reliability under thermal cycling while preserving manufacturing ease through the extrusion process.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure with distinct functional layers: smooth inner conduit for flow, metal or reinforcement interlayer for strength, and outer conduit for protection. The recessed groove design with anchor features creates a mechanically interlocked composite that resists de-lamination while allowing efficient manufacturing through extrusion and expansion processes.

Inventive Principle:
Principle #40Composite materials

2Temperature

If thermoplastic pipes are used to convey hot water, then temperature resistance is improved, but thermal expansion causes axial forces that lead to buckling and system failure

Engineering Contradiction:
Improvetemperature resistanceVSAvoiddimensional stability
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The patent segments the pipe structure into multiple functional layers with a recessed groove system that creates discrete expansion zones. The anchor features in the groove allow controlled movement and stress distribution along the pipe length, preventing buckling while maintaining dimensional stability. This segmentation enables the pipe to handle thermal expansion forces without system failure.

Inventive Principle:
Principle #1Segmentation

3Strength

If pipe wall thickness is increased to prevent buckling under thermal expansion, then temperature resistance and structural strength are improved, but impact resistance and ease of installation deteriorate

Engineering Contradiction:
Improvebuckling resistanceVSAvoidimpact resistance
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by concentrating reinforcement in specific zones through the metal or reinforcement interlayer with anchor features, rather than uniformly thickening the entire pipe wall. This localized reinforcement provides buckling resistance where needed while maintaining overall pipe flexibility and impact resistance. The smooth inner conduit layer preserves ease of installation and flow characteristics.

Inventive Principle:
Principle #3Local quality

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 solution achieves enhanced temperature resistance up to 95°C, improved impact resistance, and reduced de-lamination, meeting advanced ASTM standards, while maintaining flexibility and cost-effectiveness, with no leaks observed under high pressure and temperature conditions.

Implementation Method 1

an adhesive layer adhesively securing the inner conduit to the inner surface of the metal conduit and to the outer surface of the metal conduit

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

provision of continuous external hot air blower setup to maintain the constant and precise temperature of adhesive layer for better bonding

Methodology Applied
Scientific EffectConvection heating: Convection

Implementation Method 3

laser welding the strip to close the gap without burning the inner conduit beneath to provide a continuously welded metal conduit

Methodology Applied
Scientific EffectLaser welding: Laser Beam Welding

Data Source

PatentUS20230392720A1CPVC multilayer composite pipe with improved temperature and delamination resistance and process for making pipe
Publication Date: 2023.12.07 ASTRAL LTD

AI summary

The present invention relates to aCPVC multilayer composite pipe with improved impact resistance, temperature resistance and de-lamination resistance and process for making pipe. The present invention provides composite pipe with altered thickness having two conduits of CPVC separated by metal conduit. The invention provides pipe with multilayered structure having metal interlayer firm engagement through adhesive application. The process provides inventive intact arrangement of two different materials that are generally difficult to resists for clasping together in circular compact system specifically at elevated stressed conditions (i.e. temperature and pressure). In the current state of the art composite pipe manufacturing reflects de-lamination of the layers closely held together with adhesive application at interlayer. The present invention discloses CPVC composition along with adhesive which collectively provides superlative quality of holding dual layers of CPVC conduits with metal interlayer and low expansion to the pipe during elevated temperature and pressure conditions.