Continuous Insulated Pipe Foam Production
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Solution Overview
Problem
Existing methods for producing insulated pipes face challenges such as labor-intensive and cost-intensive production, coarser cell structure, thicker outer jackets, and difficulty in achieving uniform bulk density and large diameters, leading to increased raw material usage and thermal conductivity issues.
Innovation Solution
A continuous method involving a polyurethane system with thixotropic properties, comprising an isocyanate component and a polyol, is used to fill the gap between medium and casing pipes, with a thixotropic agent added to ensure stable foam distribution and application, allowing for continuous production of pipes with uniform density and large diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If discontinuous tube-in-tube production is used with star-shaped spacers, then pipe segments can be manufactured, but production becomes labor-intensive and cost-intensive
Solution Approach 1:
The patent implements continuous production by eliminating the discontinuous assembly process. The polyurethane system is continuously injected into the annular gap between pipes, and the film is continuously applied to form the outer jacket, replacing the traditional discontinuous tube-in-tube production method that required manual assembly of pipe segments with star-shaped spacers.
Solution Approach 2:
The patent divides the production process into distinct continuous stages: pipe preparation, polyurethane injection, and film application. This segmentation allows each stage to operate continuously independently, improving overall productivity while maintaining ease of manufacture through standardized continuous operations.
2Manufacturing precision
If polyol components with low viscosity are used to fill the annular gap, then good flowability is achieved, but the cell structure becomes coarser
Solution Approach 1:
The patent modifies the viscosity parameter of the polyol component by using a viscosity range of 300-2000 mPas instead of lower viscosity values. This parameter change allows the polyurethane system to maintain good flowability for complete gap filling while producing a finer cell structure, resolving the contradiction between flowability and cell structure quality.
3Strength
If thicker outer jackets are applied to withstand internal pressure, then structural strength is improved, but raw material usage and production costs increase
Solution Approach 1:
The patent uses a thin film applied continuously to form the outer jacket, replacing traditional thick outer jackets. The film provides sufficient structural strength to withstand internal pressure during foaming while minimizing raw material usage. The continuous film application creates a uniform thin protective layer that maintains strength without the excess material of conventional thick jackets.
4Productivity
If longer individual tube segments are manufactured to reduce socket connections, then installation efficiency improves, but production technical problems increase
Solution Approach 1:
The patent enables continuous production of insulated pipes of any required length by eliminating the technical constraints of discontinuous manufacturing. The continuous polyurethane injection and film application processes can accommodate long pipe segments without the quality issues that plague traditional discontinuous methods, thus enabling both installation efficiency and simplified production.
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 method achieves a uniformly distributed bulk density, homogeneous foam structure, and low thermal conductivity, reducing material usage and production costs while ensuring the polyurethane system remains within the pipe, enabling the production of insulated pipes with improved physical characteristics.
Implementation Method 1
foaming and allowing the polyurethane system to cure
Implementation Method 2
foaming and allowing the polyurethane system to cure
Implementation Method 3
the polyurethane system having thixotropic properties
Data Source
AI summary
The present invention relates to a continuous method for the production of an insulated tube comprising at least one medium tube, a shell tube, a layer of at least one polyurethane between the at least one medium tube and shell tube and a film sleeving between the at least one polyurethane and the shell tube, comprising at least the steps (A) providing at least one medium tube and one film sleeving continuously formed from a film in a gripper-belt, wherein the at least one medium tube is arranged inside the film sleeving in such a manner that between the at least one medium tube and film sleeving a gap is formed, (B) charging a polyurethane system comprising at least one isocyanate component (a) and at least one polyol (b) into the gap, (C) foaming and curing the polyurethane system, and (D) applying a layer of at least one material to the film sleeving in order to form the shell tube, wherein the polyurethane system has thixotropic properties.