Ammonia-Treated Silica Insulation for Dimensional Stability
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Solution Overview
Problem
Binder-free thermal insulation moldings experience volume expansion and cracking after pressing, leading to poor mechanical stability and dimensional inaccuracies, which complicates the production of dimensionally accurate thermal insulation products.
Innovation Solution
A method involving treating hydrophilic silica-containing thermal insulation moldings with gaseous ammonia in a controlled pressure chamber to enhance compressive strength, where the pressure difference is maintained between 20 mbar and 5 bar, and optionally treating with organosilicon compounds to make the insulation hydrophobic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If binder-free thermal insulation moldings are pressed to achieve dimensional accuracy, then manufacturing precision is improved, but the moldings become cracked and lose mechanical stability
Solution Approach 1:
The patent applies preliminary action by treating the hydrophilic silica-containing thermal insulation mixture with ammonia vapor before the pressing process. This pre-treatment modifies the silica surface chemistry in advance, creating conditions that prevent cracking and maintain mechanical stability during subsequent compression, thereby resolving the contradiction between achieving dimensional accuracy and maintaining mechanical stability.
Solution Approach 2:
The patent changes the chemical parameter of the silica surface by introducing ammonia treatment, which modifies the surface properties of the hydrophilic silica. This parameter change enables the material to withstand pressing forces without cracking, thus improving both manufacturing precision and mechanical stability simultaneously.
2Stability of the object's composition
If ammonia is added before pressing to reduce volume expansion, then volume stability is improved, but the process complexity increases
Solution Approach 1:
The patent replaces the conventional mechanical mixing method of incorporating ammonia with a chemical vapor treatment process. Instead of mechanically mixing ammonia into the binder-free mixture, the invention uses ammonia vapor to treat the hydrophilic silica surface, achieving volume stability through chemical modification rather than mechanical incorporation, thereby simplifying the overall process.
Solution Approach 2:
The patent utilizes an ammonia vapor atmosphere to treat the thermal insulation mixture before pressing. This inert-like atmospheric treatment environment allows for controlled chemical modification of the silica surface without introducing complex mechanical mixing equipment or processes, thus improving volume stability while maintaining process simplicity.
3Strength
If gaseous ammonia is supplied at high pressure to enhance compressive strength, then strength is improved, but thermal insulation properties deteriorate due to increased ammonia content
Solution Approach 1:
The patent replaces high-pressure gaseous ammonia treatment with a vapor-phase ammonia treatment process. This substitution allows ammonia to be introduced in a controlled vapor state that reacts with the hydrophilic silica surface at lower pressures, achieving enhanced compressive strength through surface modification without excessive ammonia penetration that would compromise thermal insulation properties.
Solution Approach 2:
The patent changes the physical state parameter of ammonia from high-pressure gas to controlled vapor, and optimizes the concentration and exposure time parameters. This parameter optimization enables sufficient ammonia uptake to improve compressive strength while maintaining thermal insulation performance by preventing over-saturation with ammonia.
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 significantly improves the compressive strength of thermal insulation moldings, allowing for more stable and dimensionally accurate products, even after compression, while minimizing ammonia content to maintain thermal insulation properties.
Implementation Method 1
a hydrophilic silica-containing thermal insulation molding is treated with ammonia by placing the thermal insulation molding in a chamber and supplying gaseous ammonia
Implementation Method 2
The atmospheric pressure is approximately 1013 mbar. Even better results are obtained with an embodiment in which the process is carried out in such a way that the pressure in the chamber before the gaseous ammonia is introduced is less than atmospheric pressure
Data Source
AI summary
The invention relates to a method for producing an ammonia-treated, hydrophilic molded heat-insulating element. According to the invention, a molded heat-insulating element comprising hydrophilic silicic acid is treated with ammonia, the molded heat-insulating element is introduced into a chamber and ammonia is fed thereto until the pressure difference is Δp ≥ 20 mbar. The invention also relates to a method for producing a molded heat-insulating element comprising hydrophobic silicic acid, the ammonia-treated hydrophilic molded heat-insulating element being treated with an organosilicon compound.