Insulated Pipe Production With Adhesion-Promoted Polyurethane Foaming
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Solution Overview
Problem
The continuous production of insulated pipes with high axial shear strength and uniform bulk density is challenging due to manufacturing processes that often result in insufficient adhesion and faulty production, leading to increased costs and downtime.
Innovation Solution
A method involving the application of an adhesion promoter to the surface of a medium pipe before filling a polyurethane system comprising an isocyanate component, polyol component, and catalyst into the gap between the medium pipe and a film or casing pipe, allowing the polyurethane system to foam and cure, which significantly enhances the axial shear strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If polyurethane foam is used as insulating material in continuous pipe production, then thermal insulation performance is improved, but adhesion between the foam and medium pipe is insufficient leading to production defects
Solution Approach 1:
The patent introduces an adhesion promoter as an intermediary substance applied to the medium pipe surface before foam injection. This promoter contains reactive groups that bond with both the pipe surface and the polyurethane foam, creating a chemical bridge that significantly improves adhesion strength and eliminates delamination defects while maintaining the thermal insulation properties of the foam layer.
Solution Approach 2:
The patent modifies the chemical parameters of the pipe surface by applying an adhesion promoter that changes the surface energy and reactivity. This parameter change enables the subsequently injected polyurethane foam to form strong chemical bonds with the surface, transforming the adhesion quality from insufficient to reliable without compromising the foam's insulating performance.
2Adaptability or versatility
If socket joints are used to connect pipe segments, then assembly flexibility is improved, but damage risk and production costs increase
Solution Approach 1:
The patent extracts and eliminates the vulnerable socket joint component from the piping system by enabling continuous pipe production. Through improved adhesion promoter technology and continuous foam filling, the system achieves reliable connections without requiring separate socket joints, thereby removing the source of damage risks associated with these protruding components.
Solution Approach 2:
The patent creates a composite structure where the adhesion promoter layer combines with the polyurethane foam and pipe surface to form an integrated, homogeneous connection. This composite approach eliminates the need for separate mechanical joining components like socket joints, reducing damage risk while maintaining assembly flexibility through continuous production capabilities.
3Ease of manufacture
If discontinuous pipe production process is used, then manufacturing simplicity is maintained, but production efficiency and cost-effectiveness deteriorate
Solution Approach 1:
The patent implements continuous pipe production by maintaining uninterrupted adhesion promoter application and polyurethane foam injection along the pipe length. This continuous action eliminates the start-stop nature of discontinuous processing, significantly improving production efficiency and cost-effectiveness while the automated application systems maintain manufacturing simplicity through standardized continuous operations.
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
This method doubles the axial shear strength of insulated pipes, achieving uniform bulk density and low thermal conductivity, enabling the continuous production of insulated pipes with large diameters and high bulk densities, meeting industry standards for district heating networks.
Implementation Method 1
an adhesion promoter is applied to the surface of the medium pipe facing the film tube or jacket pipe
Implementation Method 2
the injection of a polyurethane system comprising at least one isocyanate component (a) containing at least one isocyanate, a polyol component (b) and at least one catalyst into the gap before the adhesion promoter is completely cured, and the foaming and curing of the polyurethane system
Implementation Method 3
the foaming and curing of the polyurethane system
Implementation Method 4
polyurethane foams can be used as insulating material
Data Source
AI summary
The invention relates to a method for producing insulated pipes, comprising the providing of a medium pipe and a film hose, continuously formed from a film, or a medium pipe and a jacket pipe, wherein the medium pipe is arranged within the film hose or the jacket pipe and a gap is formed between the medium pipe and film hose or jacket pipe, wherein a bonding agent is applied to the surface of the medium pipe facing the film hose or jacket pipe, the filling of a polyurethane system, at least comprising an isocyanate component (a) containing at least one isocyanate, a polyol component (b) and at least one catalyst into the gap before the bonding agent is completely cured, and allowing the polyurethane system to foam and cure. The invention further relates to insulated pipes, obtainable or obtained according by the method according to the invention.