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Glass wool is a glass fiber in a
category, is a man-made inorganic fibers. Using quartz sand, limestone,
dolomite
and other natural ore as the main raw material, with a number of soda
ash, borax and other chemical raw materials
into glass. In the melted state, with the help of external force into
the floc-type flaxation of fine fibers,
fibers and fibers for the three-dimensional cross-linked to each other,
showing a lot of small gaps. This gap can
be regarded as porosity. Therefore, glass wool can be regarded as porous
material, with good insulation, sound
absorption performance. The glass wool is a kind of inorganic fiber,
which has good shape, small bulk density,
thermal conductivity, thermal insulation, sound-absorbing performance
and corrosion resistance. Decorated,
chemical stability. Mineral wool stone is the main component of blast
furnace slag, phosphate slag, fly ash and
so on. Centrifugal glass wool centrifugal glass fiber internal fluffy
staggered, there are a large number of tiny
pores, is a typical porous sound-absorbing material, has good sound
absorption characteristics. Centrifugal glass
wool can be made of wall panels, ceilings, space absorbing body, etc.,
can absorb a large number of room sound
energy, reduce reverberation time, reduce indoor noise. Centrifugal
glass wool absorption characteristics not
only with the thickness and bulk density, but also with the cover
material, structure and other factors. In
building applications need to take into account the cost, aesthetics,
fire, moisture, dust, anti-aging and other
issues. Centrifugal glass wool is a porous sound-absorbing material, has
a good sound absorption performance.
Centrifugal glass wool can absorb sound reason is not due to surface
roughness, but because of a large number of
internal and external connectivity of the tiny pores and holes. When the
sound waves into the centrifugal glass
wool, the sound waves along the pore into the material inside, causing
air molecules in the gap vibration. Due to
the viscous resistance of air and air molecules and pore wall friction,
sound energy into heat loss. Centrifugal
glass wool on the sound of high-frequency sound better performance.
Influence of centrifugal glass wool sound
absorption performance of the main factors are the thickness, density
and air flow resistance. The density is the
weight per cubic meter of material. Air flow resistance is the ratio of
air pressure and air velocity on both
sides of the material per unit thickness. Air flow resistance is the
most important factor affecting the sound
absorption performance of centrifugal glass wool. Flow resistance is too
small, indicating that the material is
sparse, easy to pass through the air vibration, sound absorption
performance; flow resistance is too large,
indicating dense material, difficult to introduce air vibration, sound
absorption performance. For centrifugal
glass wool, the sound absorption performance of the best flow
resistance. In practical engineering, the
determination of air flow resistance is more difficult, but can be rough
estimates and control of thickness and
bulk density. 1, with the thickness increases, the low-frequency sound
absorption coefficient increased
significantly, but not high-frequency changes (high-frequency absorption
is always larger). 2, the same
thickness, bulk density increased, the low-frequency sound absorption
coefficient also increased; but when the
bulk density increased to a certain extent, the material becomes dense,
the flow resistance is greater than the
best flow resistance, sound absorption coefficient decreased. For the
thickness of more than 5cm bulk density of
16Kg / m3 centrifugal glass wool, low-frequency 125Hz is about 0.2, in
the high-frequency (> 500Hz) sound
absorption coefficient has been close to 1. When the thickness from 5cm
continue to increase, the low-frequency
sound absorption coefficient gradually increased, when the thickness is
greater than 1m above, the low-frequency
125Hz sound absorption coefficient will be close to 1. When the
thickness of the same volume density increases,
the centrifugal glass wool low-frequency sound absorption coefficient
will also continue to improve, when the
bulk density close to 110kg / m3 when the maximum sound absorption
performance, 50mm thick, close to the
frequency of 125Hz 0.6-0.7. When the bulk density exceeds 120kg / m3,
the sound absorption performance will
decrease, because the material becomes dense, the high-frequency sound
absorption performance is greatly
affected, when the bulk density exceeds 300kg / m3, the sound absorption
performance is reduced a lot. Commonly
used in architectural acoustics glass wool thickness of 2.5cm, 5cm,
10cm, bulk density of 16,24,32,48,80,96,112
kg / m3. Centrifugal glass wool, typically 5 cm thick, 12-48 kg / m3 is
used. Centrifugal glass wool sound
absorption performance and installation conditions are closely related.
When the glass wool board behind the air
layer, with the same thickness without air layer of glass wool board
similar to the sound absorption. Especially
in the low-frequency sound absorption performance than the material is
attached to the hard bottom surface will
be greatly improved, sound absorption coefficient will increase with the
thickness of the air layer, but
increased to a certain value after the effect is not obvious. The use of
different bulk density of glass wool
stacked together and form a gradually increasing bulk density of the
form, you can get a greater sound absorption
effect. For example, a layer of 2.5cm thick 24kg / m3 cotton board and a
layer of 2.5cm thick 32kg / m3 of cotton
together and the sound absorption effect is better than a layer of 5cm
thick 32kg / m3 of cotton. The 24-mm-thick
glass wool board was made into a triangular wedge with a 1-m-long
cross-section, and the material surface density
gradually increased, and the average sound absorption coefficient could
be close to 1. Centrifugal glass wool in
the use of the building, the surface is often accompanied by a certain
sound through the role of finishes, such
as less than 0.5mm plastic film, metal mesh, screens, fire cloth, glass
cloth, etc., can basically maintain the
original sound absorption characteristics. Centrifugal glass wool with
fire, heat, easy to cut and other fine
features, is the most commonly used building materials, one of sound
absorption. However, due to centrifugal
glass wool surface without decorative, and there will be spilled fiber,
it must be made of various sound-
absorbing components concealed use. The most commonly used is the lowest
cost structure is perforated gypsum
board ceiling or made of centrifugal glass wool into the perforated
plate wall, perforation rate of more than
20%, the basic can fully play out the centrifugal glass wool sound
absorption performance . In order to prevent
the glass wool spill, need to wear a perforated plate in the back of a
layer of non-woven fabrics, mulberry paper
and other acoustic fabrics, or the use of glass cloth, plastic film
wrapped glass wool. Similar to the perforated
gypsum board there are perforated metal plate (such as aluminum),
perforated wood, perforated fiber cement board,
perforated mineral wool board. Glass wool board can be made after the
treatment of sound absorption ceiling or
sound-absorbing wall panels. Usually the 80-120kg / m3 of glass wool
board around the glue cured after the
outsourcing of fire-retardant sound-absorbing fabric to form both
beautiful and easy to install sound-absorbing
wall panels, common size is 1.2m กม 1.2m, 1.2m กม 0.6m, 0.6 m x 0.6 m, and
a thickness of 2.5 cm or 5 cm. But
also in the 110Kg / m3 of glass wool on the surface of the sound
directly through the sound-absorbing decorative
material formed by the ceiling. Whether it is glass wool sound
absorption wall panels or sound-absorbing ceiling,
need to use high-density glass wool, and after a certain degree of
strengthening to prevent deformation or too
soft plate. This kind of building materials both good decorative and
retains the centrifugal glass wool good
sound absorption characteristics, noise reduction coefficient NRC
generally can reach more than 0.85. In the
gymnasium, workshops and other large space, in order to noise
absorption, often using centrifugal glass wool as
the main sound-absorbing material. Sound absorbers can be made into
plates, columns, cones or other shaped bodies
as required. Absorbent body filled with centrifugal glass wool, the
surface of the use of acoustic surface
wrapped. As the sound absorber has a number of surface absorption, sound
absorption efficiency is high. In the
road noise barriers, in order to prevent noise reflection, need to take
sound absorption measures for the vehicle
side, often also use centrifugal glass wool as a filler material, the
surface layer is perforated metal plate of
the barrier plate. In order to prevent the glass wool absorb moisture in
the outdoor, sometimes using PVC or
plastic film wrapped
.
.