Man-Made Vitreous Fibres via Cascade Spinner
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Solution Overview
Problem
Man-made vitreous fibre (MMVF) substrates face challenges in achieving low thermal conductivity, high air flow resistivity, skin-friendliness, and environmental sustainability while maintaining effectiveness at high temperatures, often requiring increased volume which increases costs and environmental impact.
Innovation Solution
A method and apparatus for manufacturing MMVF using a cascade spinner with a set of rotors creating specific acceleration fields and a mineral melt composition, resulting in fibres with controlled median length and diameter, which are then formed into a bonded web with a cured binder for improved insulation and fire protection properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the volume of MMVF substrate is increased to increase resistance to heat transfer, then the thermal insulation performance is improved, but the cost, space requirement, and environmental impact increase
Solution Approach 1:
The invention changes the physical and chemical parameters of the MMVF substrate by controlling fibre diameter (reducing to ≤2.5 μm) and using specific binder compositions. These parameter changes improve thermal insulation performance per unit volume, allowing reduced substrate volume while maintaining or enhancing heat transfer resistance
Solution Approach 2:
The invention uses composite materials combining MMVF fibres with specific binder compositions that include water glass and organic binders. This composite structure enhances the thermal insulation efficiency of the substrate, improving performance without increasing volume
2Reliability
If the air flow resistivity of MMVF substrate is increased to reduce air passage, then the heat withstand ability is improved, but the acoustic insulation may be compromised
Solution Approach 1:
The invention applies local quality by creating specific fibre diameter distributions and binder placements within the substrate. The fibre diameter is controlled to ≤2.5 μm with specific length-to-diameter ratios, creating local structural variations that simultaneously manage air flow and acoustic properties
Solution Approach 2:
The invention uses porous material structures with controlled porosity through fibre arrangement and binder composition. The porous structure allows controlled air flow resistance while maintaining acoustic insulation through tortuous air paths that attenuate sound
3Ease of operation
If fibre diameter is reduced to improve skin-friendliness, then the handling comfort is improved, but the structural strength may be reduced
Solution Approach 1:
The invention changes the parameter of fibre diameter to ≤2.5 μm while controlling the length-to-diameter ratio to maintain structural integrity. The specific binder composition and curing parameters are adjusted to compensate for the reduced fibre diameter, maintaining structural strength while improving skin-friendliness
Solution Approach 2:
The invention uses composite materials with fibres combined with specific binder ratios (water glass to organic binder in 9:1 to 1:9 range). This composite structure provides mechanical reinforcement that compensates for the reduced fibre diameter, maintaining structural strength while using finer fibres for better handling comfort
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 approach results in MMVF substrates with lower thermal conductivity, higher air flow resistivity, improved skin-friendliness, and reduced environmental impact, suitable for high-temperature applications with enhanced acoustic and heat insulation properties.
Implementation Method 1
the first rotor rotates to give an acceleration field of from 25 to 60 km/s2 and the second and third rotors each rotate to give an acceleration field of at least 125 km/s2, pouring the melt on to the periphery of the first rotor; wherein melt poured on to the periphery of the first rotor in the set is thrown on to the periphery of the subsequent rotors in turn and fibres are thrown off the rotors
Data Source
AI summary
The invention provides a method of manufacture of man-made vitreous fibers (MMVF) comprising: providing a fiberizing apparatus, wherein the fiberizing apparatus comprises: a set of at least three rotors each mounted for rotation about a different substantially horizontal axis; wherein each rotor has a driving means; rotating the rotors; wherein the first rotor rotates to give an acceleration field of from 25 to 60 km/s2 and the second and third rotors each rotate to give an acceleration field of at least 125 km/s2, providing a mineral melt, wherein the melt has a composition comprising the following, expressed by wt of oxides: SiO2 in an amount of from 33 to 45 wt %, Al2O3 in an amount of from 16 to 24 wt %, an amount of K2O and/or Na2O, an amount of CaO and/or MgO, wherein the ratio of the amount of Al2O3 to the amount of SiO2 is in the range 0.34-0.73, wherein the ratio of the total amount of K2O and Na2O, to the total amount of CaO and MgO, is less than 1; pouring the melt on to the periphery of the first rotor; wherein melt poured on to the periphery of the first rotor in the set is thrown on to the periphery of the subsequent rotors in turn and fibers are thrown off the rotors; and collecting the fibers that are formed. Man-made vitreous fibers (MMVF) can thus be formed having a median length of 100 to 300 μm, a median diameter of not more than 2.5 μm, and wherein the ratio of the median fiber length to median fiber diameter is 25 to 500.