Insulated Pipe Foaming via Catalyst Timing
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Solution Overview
Problem
Existing methods for producing insulated pipes face challenges such as high thermal conductivity due to large cell diameters, uneven foam density distribution, and limited insulation layer thickness, which increase production time and costs, while also being sensitive to environmental conditions during on-site assembly.
Innovation Solution
A method involving a polyurethane system with a catalyst that initiates polymerization before filling is complete, using a polyol mixture with high viscosity and specific amine catalysts to achieve rapid foaming and uniform density, allowing for shorter start times and increased insulation layer thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If polyurethane system with long start time is used, then good pre-distribution in the pipe is achieved, but cell diameters increase leading to higher thermal conductivity
Solution Approach 1:
The patent changes the chemical parameters of the polyurethane system by selecting specific polyols with controlled reactivity and using particular catalysts (organometallic compounds like tin octoate) to adjust the start time to be equal to or slightly less than filling time. This parameter optimization allows the foam to begin forming at the optimal moment, creating small cell diameters (0.3-1.5mm) while maintaining uniform distribution throughout the pipe.
2Volume of stationary object
If slow reaction profile is used, then larger pipe dimensions can be filled, but production time increases
Solution Approach 1:
The patent applies preliminary action by ensuring the polyurethane system starts reacting exactly when filling completes or slightly before. This timing control allows the foaming process to begin with optimal conditions already in place, enabling rapid cell formation and hardening that completes in 5-15 minutes, significantly reducing production time while accommodating large pipe dimensions up to 2 meters in diameter.
3Ease of operation
If polyol component with low viscosity is used, then good flowability is achieved, but filling time increases
Solution Approach 1:
The patent optimizes the viscosity parameter of the polyol component to a specific range (500-2000 mPas at 20°C) that balances flowability and filling speed. This parameter selection, combined with the controlled start time approach, allows the low-viscosity polyol to flow rapidly into the pipe during filling while the reaction begins at the optimal moment, eliminating the need for excessively long filling times associated with very low viscosity materials.
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 approach results in insulated pipes with low thermal conductivity, improved density distribution, and increased productivity, enabling longer pipe segments with enhanced insulation efficiency and reduced production costs.
Implementation Method 1
a polyurethane system comprising at least one isocyanate component (a), at least one polyol mixture (b) and at least one catalyst... foaming and allowing the polyurethane system to harden
Implementation Method 2
Pipes insulated with polyurethane foams... due to its excellent insulating properties
Data Source
AI summary
The invention relates to a method for producing insulated pipes, to the use of a polyurethane system comprising an isocyanate component (a), a polyol mixture (b), and at least one catalyst to produce insulated pipes, wherein the starting time for the polyurethane system is less than the time for filling the pipe with the polyurethane system, to the use of special amines as catalysts in a polyurethane system for producing insulated pipes, and to an insulated pipe that can be obtained by the method according to the invention.