- Posted by: Bella
- Category: FOIL-CLAD GLASS WOOL, GLASS WOOL BLANKET, News, Product, PRODUCTS
glass wool blanket with Aluminium foil for oven
What is centrifugal glass wool？
Centrifugal glass wool belongs to porous sound absorbing material, and has good sound absorption property. The reason why centrifugal glass wool can absorb sound is not due to rough surface, but because of a large number of tiny pores and holes connected inside and outside. When the sound wave is incident on the centrifugal glass wool, the sound wave can enter the material along the pore, causing the vibration of the air molecules in the gap. Due to the viscous resistance of air and the friction between air molecules and the pore wall, the sound energy can be transformed into heat energy and then consumed.
Sound absorption property
Centrifugal glass wool has good sound absorption performance in medium and high frequency. The main factors affecting the sound absorption properties of centrifugal glass wool are thickness, density and air flow resistance. The density is the weight of the material per cubic meter. Air flow resistance is the ratio of air pressure and air velocity on both sides of a material at unit thickness. Air flow resistance is the most important factor affecting the sound absorption properties of centrifugal glass wool. The flow resistance is too small, which shows that the material is sparse, the air vibration is easy to pass through, the sound absorption property is reduced, the flow resistance is too large, the material is dense, the air vibration is difficult to be introduced, and the sound absorption performance is also decreased. For centrifugal glass wool, the sound resistance has the best flow resistance.
In practical engineering, it is difficult to measure air flow resistance, but it can be roughly estimated and controlled through thickness and bulk density.
- With the increase of thickness, the absorption coefficient of mid and low frequency increases significantly, but the high frequency does not change much.
2, the thickness is constant, the bulk density increases, the medium and low frequency sound absorption coefficient also increases, but when the bulk density increases to a certain extent, the material becomes denser, the flow resistance is greater than the best flow resistance, and the sound absorption coefficient decreases. For centrifugal glass wool with a thickness of more than 5cm and a volume density of 16Kg/m3, the low frequency 125Hz is about 0.2, and the absorption coefficient of medium high frequency (>500Hz) is close to 1. When the thickness increases from 5cm, the sound absorption coefficient of low frequency gradually increases. When the thickness is above 1m, the sound absorption coefficient of low frequency 125Hz will also be close to 1. When the thickness is constant and the bulk density increases, the low frequency absorption coefficient of the centrifuge glass cotton will also increase. When the bulk density is close to 110kg/m3, the sound absorption performance reaches the maximum, and the 50mm thickness and the frequency 125Hz are close to 0.6-0.7. When the bulk density exceeds 120kg/m3, the sound absorption performance decreases, because the material becomes compact and the medium and high frequency sound absorption performance is greatly affected. When the bulk density exceeds 300kg/m3, the sound absorption property is reduced a lot. The thickness of sound-absorbing glass wool commonly used in architectural acoustics is 2.5cm, 5cm and 10cm. The bulk density is 16, 24, 32, 48, 80, 96 and 112kg/m3. Usually use 5cm thick, 12-48kg/m3 centrifugal glass cotton.
The sound absorption property of centrifugal glass wool is also closely related to the installation conditions. When the air layer is behind the glass wool board, the sound absorption effect is similar to that of the glass wool board with the same thickness without air layer. In particular, the sound absorption performance of the medium and low frequency will be greatly increased than the material on the hard bottom, and the sound absorption coefficient will increase with the thickness of the air layer, but the effect is not obvious after increasing to a certain value.
The use of different bulk density of glass and cotton stack together to form a form of gradual increase in bulk density, can achieve greater sound absorption effect. For example, the sound absorption effect of a layer of 2.5cm thick 24kg/m3 cotton board and a 2.5cm thick 32kg/m3 cotton board is better than that of a layer of 5cm thick 32kg/m3 cotton board. The 24kg/m3 glass wool board is made into a 1m long wedge with triangular shape. The density of material surface increases gradually, and the average sound absorption coefficient can be close to 1. Glass cotton is a kind of flexible glass fiber made from a glass fiber with a diameter of only a few microns. It is a kind of glass fiber made from a glass fiber with a diameter of only a few microns. It is the best material for thermal insulation, sound absorption and noise reduction in building, because it has a large number of small air gaps, making it warm, sound absorption and noise reduction and safety protection. Unique advantages, unique technology, compression packaging rebound rate of 99.2%. Soft and slender glass fiber can minimize the occurrence of catkins in construction.
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