Rigid Polyurethane Foam Insulation Uniform Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing polyurethane foams used for insulating large hollow spaces, such as pipe systems, face challenges with uneven foam distribution, high thermal conductivity due to large cell diameters, and the occurrence of a 'push zone' at pipe ends, which affects compressive strength and water absorption.
Innovation Solution
A low-viscosity polyurethane system is introduced with rigid polyurethane foam constituents that cure uniformly within a mold, forming a rigid polyurethane foam with small cell diameters and improved flow properties, ensuring consistent foam density and reduced thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a long cream time is used to achieve good predistribution in large hollow spaces, then the liquid reaction mixture has sufficient time to distribute uniformly, but the cell diameters increase significantly leading to higher thermal conductivity
Solution Approach 1:
The patent modifies the chemical composition parameters of the polyurethane system by incorporating specific catalysts and additives that alter the reaction kinetics. This enables the foam to achieve both long cream time for uniform distribution and controlled cell growth to maintain small cell diameters, thereby resolving the contradiction between distribution uniformity and thermal conductivity
Solution Approach 2:
The invention uses a composite polyurethane formulation combining multiple components with different functions: polyols, isocyanates, catalysts, and additives work synergistically to provide both extended cream time and controlled foaming characteristics, achieving uniform distribution while maintaining low thermal conductivity
2Stability of the object's composition
If high-functionality polyols with high viscosity are used to achieve good flow in stage 2, then the foam structure is stabilized, but predistribution in stage 1 becomes poor
Solution Approach 1:
The patent divides the polyol component into multiple segments or uses a blend of polyols with different viscosity characteristics. This segmentation allows the mixture to exhibit low viscosity during predistribution (stage 1) while maintaining structural stability during foaming (stage 2), thereby resolving the contradiction between flowability and structure stability
Solution Approach 2:
The invention creates a dynamic viscosity profile where the polyol mixture transitions from low viscosity in the liquid state for uniform distribution to high viscosity upon reaction initiation for structure stabilization. This dynamic property change enables both good predistribution and foam structure stability
3Device complexity
If relatively long individual pipe segments are used to reduce the number of muff connections, then installation complexity is reduced, but the annular gap filling becomes more difficult with larger gaps requiring slower reaction
Solution Approach 1:
The patent adjusts the reaction parameters of the polyurethane foam by modifying catalyst concentration and composition, enabling the foam to maintain a slow, controlled reaction that allows complete filling of large annular gaps in long pipe segments while ensuring uniform distribution and proper curing
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 solution enables quick curing and uniform foam distribution, reducing thermal conductivity and eliminating the 'push zone' issue, thereby enhancing the insulating properties and productivity of large hollow spaces.
Implementation Method 1
A liquid reaction mixture is introduced into the hollow spaces by means of a polyurethane metering machine, and this mixture has to become distributed in still liquid form in the hollow space before the reaction commences. Once the reaction commences, further distribution due to flow of the foam which steadily increases in viscosity takes place
Implementation Method 2
A low-viscosity polyurethane system is introduced with rigid polyurethane foam constituents that cure uniformly within a mold, forming a rigid polyurethane foam with small cell diameters and improved flow properties
Implementation Method 3
the foam has to achieve good predistribution in the hollow space in the liquid, i.e. still unreacted, state. Furthermore, in the case of large hollow space dimensions, sufficient time has to be available for the polyurethane material required to be introduced into the hollow space within the cream time
Data Source
AI summary
The present invention relates to a rigid polyurethane foam in which rigid polyurethane foam constituents are embedded in a polyurethane matrix, articles which are enveloped by such a foam for insulation and corresponding production processes.