Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION: This invention relates to sound
absorbing panels for use in industrial sound control.
DESCRIPTION OF THE PRIOR ART: In recent years, industry has
become increasingly aware of noise pollution, and, consequent
there has developed a need for sound control and sound
absorption systems. The most common method used for sound
control is thin, sound absorbing panels attached to the wall
surface of the room where sound control is desired. Perhaps
the latest design for a sound absorbing panel is the design
shown in U. S. Patent 3,858,676, w~ich includes a perforated
backing, a sound absorbing core, and a heavy textile front.
While this design is suitable for attachment to a wall
surface, it is unsuitable for use in those areas spaced
apart from a wall surface where the sound absorbing panel
must absorb sound from *wo opposing directions. Additionally
the use of a heavy textile material is expensive, difficult
to assemble, and easily subject to damage.
Previous sound absorbing panel structures including
that shown in U~ S. Patent 3,182,747, consisting of an open, --- -
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microporous sound absorbing sheet adapted to be ~ountcd at
a predetermined distance from a wall. This panel structure
required a wall for support, ~as difficult to construct, and
was not adaptable to use ln open spaces spaced apart from an
exlsting wall.
In U. S. Patent 2,968,327, a sound absorbing panel was
illustrated consisting of a perforated, fibrous, acoustical
material produced by mechanically delaminating the fibrous
structure of the material in areas between the perforations
to provide openings extending laterally from the perforations
for air flow to reduce the air flow resistance of the material
significantly and thereby enhance its sound absorption
- efficiency. This type of panel was d~fficult and costly to
produce and also lacked the support necessary to span large
vertical distances between the ceiling and floor of an
existing room.
In U. S. Patent 3,448,823, an acoustical panel was
disclosed having a main sound attenuating body of integrated
fibers and a fabric facing adhered thereto. The fabric was
a woven glass fiber yarn, having nubs of glass fiber extending
outwardly from the fabric. The use of glass fiber fabric
was expensive, and the adhering of the fabric to the fibers
also was difficult and expensive. On the other hand, U. S.
Patent 3,748,799 illustrated a sound absorbant panel wherein
two smaller members were abutted end to end and enclosed in
a channel-shaped, one piece edge member, buf this design
required the use of an expensive, and difficult to apply,
; double-faced adhesive tape along the edge of the panel.
While this patent disclosed a facing material on the sound
3 absorPtion nmaterial, the construction of the unit was too
costly for wide spread use.
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In [1. S. Patent 3,630,310, a sound absorbing rence ~las
provided consisting of a solid upright backing panel on a
framework and a layer of sound absorblng roam plastic material
on the face of the plate directed toward the source of the
noise by a screen of fabric, plastic, or metal practically
transparent to the sound. This panel system, however,
required a roof for protection, since the sound absorbant
material was exposed to the elements and readily subject to
damage thereby. In one other prior sound absorbing panel
design, U. S. Patent 3,253,947 disclosed a flexible sound
attenuating material comprising a fabric face having, on at
least one surface, a continuous elastomeric film containing
randomly dispersed discrete parbicles of a high dense solid,
such as lead. This panel system was very expensive due to
the cost of the lead and could not use conventional, known
sound absorbing materials for sound control. Additionally,
the panels were easily sub~ect to damage.
Even though there has been considerable activity in the
design of sound absorbing panels, there has yet to be developed
a sound absorbing panel which ~as a sound absorblng material
completely protected from the e]ements. There has also not
yet been provided an efficient sound absorbing panel which
provides a method of preventing the sound absorbing material
from being dispersed into the atmosphere, a condition normally
occuring due to normal exposure of sound absorbing panels.
Additionally, there has not yet been provided a sound
absorblng panel which is highly successful in uses spaced
apart ~rom a wall or requiring sound absorptlon from opposing ~ -
directions. In other words, none of the known prior systems
¦ 30 are lnexpenslvely adaptable to makine a sound absorption
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wall spaced apart from an existinp, wall without first bui]dirl~,
a new wall. In addition to all the previous discussed,
unsuccessful systems, there has yet to be provided a sound
absorbing panel which is low cost and easy to assemble. The
new and novel sound absorbing panels made possible by this
invention provide the first known sound absorbing panels
which can control sound from opposing directions, and which,
- additionally, shield the sound absorbing material from the
elements while preventing the sound absorbing material from
being dispersed into the working atmosphere.
SUMMARY OF THE IN~ENTIO~
It is an ob~ect of this invention to provide a sound
¦ absorbing panel for use in industrial sound control.
¦ It is another ob~ect of this invention to provide a
¦ sound absorbing panel for use in industrial sound control
that provides for protection of the sound absorbing material
from deterioration due to exposure to the elements.
It is an additional ob~ect of this invention to provide
a sound absorbing panel for use in industrial sound control
which provides a method for preventing the sound absorbing
material from being dispersed into the atmosphere.
It is a further ob;ect of this invention to provide a
low cost, easy to assemble, highly adaptable, sound absorbing
panel.
The ob~ects of this invention are accomplished by a
sound absorbing panel for use in industrial sound cont,rol,
with the panel comprising a sound absorbing material completely
enclosed in a heat shrunk, plastic material and with the
enclosed sound absorbing material supported by a frame
extending about the outer edge of the enclosed sound absorbing
material. It is preferred that the frame t,hat encloses the
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sound absorblng materia] have a U-sllaped cross-sec~l~,n.
Any well recogl~ized sound absorbing material, generally used
in sound absorbing panels, may be used within the scope Or
this invention. Ho~ever, it is preferred to use a mineral
fiber mat having a density of from four to six pounds per
cubic foot. Other well recognized sound absorbing materials
may be used, however, including glass fiber mats having a
density sufficient to absorb sound in the intended use. The
sound absorbing material is completely enclosed in a heat
shrunk plastic material according to generally recognized
methods for heat shrink wrapping of material. Briefly
stated, this process consists of placing a plastic material
around the sound absorbing material and heating the plastic
material to cause it to shrink, bind together, and completely
enclose the sound absorbing material. Any of the well
recognized heat shrinking plastics may be used for this
purpose, including polyvinyl chloride film, polyethylene
film, polypropylene film, and polyethylene based films. A
particularly good film is a strong, clear, biaxially oriented~
heat shrirlkable copolymer of polyethylene sold undeL the E. I.
du Pont company trademark CLYSAR EHC. It must be recognized
that the heat shrinking plastic material should be adapted ~ -
for the intended use and should be of a thickness and density
such that the sound is transmitted therethrough, rather than
being reflected from the plastic material.
The various adaptations and embodiments made possible
by use of the invention described herein are numerous. A
single batt or mat of heat shrunk plastic coated, sound
absorbing material may be supported by a frame as disclosed
3 above. If additional support or protection is desirable in
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the assembled system, it can be add~d by applying a perror~ate(l
faclng material Oll one side of the enclosed sound absorbing
material. The perforated facing material can be adhered to
the plastic coating although this is not necessary, since
proper design will enable the perforated facing material to
be retained agalnst the face by the frame which extends
around the panel. If both sides of the panel require
protection, it may be desirable to include this perforated
facing on both sides of the enclosed sound absorbing material.
The particular type of perforated facing material used is
dependent upon the requirements of usage and dictated by the
exposure of the panel in usage. It can have smaller meshes
for larger strength, or have a large mesh and large openings
to provide protection with a minimum of loss of efficiency
of sound absorption. It must be understood that the perforated
facing will be likely to reflect sound, and this must be
taken into consideration when choosing the facing rnaterial.
For that reason, it is usually preferable to have a facing -
material of thin gage metal with large openings therein,
such as the facing material commonly found on furnace filters.
In some adaptations, it may be desirable to provide a
heavily supported system within the panel. In these instances,
- it may be desirable to have a solid backing on one face of
the coated, sound absorbing material, again proper design of
which will enable it to be held against the face by the
frame. This solid backing can be any solid construction
material, such as sheets of hard board or pressed fiber
board, or the like. The particular type of backing is
dictated by the degree of strength required and the other
3 requlrements made necessary by the extent of the exposure of
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the panel. It may be additionally desirable to provide a
panel which has increased support by ~laving one side o~ the
coated, sound absorbillg material faced with a solid racing
and have the other face of the coated, sound absorbing
`material faced with a perforated facing of the type hereinbefore
described. This provides a significant arnount of adaptability
of the panel system and enables it to be used in almost
every application.
In some instances, it may be necessay to use the panels
for sound control in the middle of the room, i.e. spaced
apart from an existing supporting wall structure. In these
instances, it will become necessary to stack the panels, one
upon the other, with their edges abutting to make a continuous
system, in order to make a new wall out of the panels. In
such cases, the requirements for support usually dictate the
use of a solid backing material. It may be, however, that -
- use of a solid facing material would be unacceptable because
sound control needs to be provided from opposing directions,
and the solid facing material will reflect, rather than
absorb, sound. In these instances, an embodiment of the
present invention can be provided wherein a solid facing
material is provided for support, and this facing material
is sandwiched between two of the coated, sound absorbing
panels of the type hereinbefore described. The entire
sandwiched unit is then contained and held together by a
frame extending around the outer edge thereof, and it is
preferred that the frame have a U-shaped cross-section. For -
purposes hereinbefore described, it may be desirable that
this panel system have additional outside face support,
3 and if such is necessary, one or more of the exposed faces
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may be supported by a perforated facing material in the
mannel hereinberore described.
Sound absorption control has, in the past, been provided
by sound absorbing panels, but the attachment of such panels
sometimes makes the system unacceptable, and this is particu _rly
the case when it is necessary to use sound absorbing panels
in areas spaced apart from an existing supporting structure
such as a wall. Prior known sound absorbing panels have not
been adaptable to this use because of difficulty in attachme-_
and because of lack of strength in enabling them to provide
a curtain or wall effect. Therefore, in stlll another
embodiment of this invention, sections of sound absorbing
panels are abutted, end to end, and enclosed by a frame
extending around the outside of the abutted panels. It is
generally preferred that this frame have a U-shaped cross-
section for retaining the panel sections. The panel sections
may be any of the types described previously and include a
sound absorbing material completely enclosed in a heat
shrunk plastic material. One or more of the faces of the
enclosed material may be supported by a perforated facing,
and a backing of a solid material may be provided when
desired. Likewise, a solid supporting panel may be sandwiched
between two of the sound absorbing panels, and this may
optionally have a perforated facing if desired. It is
preferred, in these installations~ that the panel sections be
supported at their abutting edges by a web extending between
the frame, and this web is preferred to have an H-shaped
cross-section, with preference given to two pieces of materia~
like that which the frame is made of, having a U-shaped
cross-section and placed back to back.
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Still other objects will readily present themselves to
one skilled in the art upon reference to the following
specifications, the drawings, and the claims.
Thus, one aspect of the present invention is defined as
a sound absorbing panel for use in industrial sound control,
the panel comprising a sound absorbing material being mineral
fiber having a density of from four to six pounds per cubic
foot wherein the sound absorbing material is completely enclosed
in a heat shrunk plastic material and supported by a frame having
an integral U-shaped cross-section, the U-shaped frame opening
inwardly with flanges of the U-shape extended inwardly of the
sound absorbing material enclosed in the heat shrunk plastic
material and the frame extending about the outer edge of the
heat shrunk plastic material enclosing the sound absorbing
material.
Another aspect of the present invention is defined as a
method for making a sound absorbing panel for use in industrial
sound control, the method comprising heat shrinking a plastic
material about a sound absorbing material, being mineral fiber
having a density of from four to six pounds per cubic foot,
completely enclosing the sound absorbing material in the heat
shrunk plastic material and thereafter providing a U-shaped
frame support, disposing the U-shaped frame to open inwardly with
flanges of the U-shape extended inwardly of the sound absorbing
material enclosed in the heat shrunk plastic material and en-
circling the heat shrunk plastic material enclosing the sound
absorbing material about its outer edge with the U-shaped frame
support.
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BRI~F DESCRIPTION OF THE DRAWINGS
This invention may be more fully described, but is not
limited, by the attached drawings, wherein:
FIG. 1 is a perspective view of one embodiment Or the
panel system Or this invention;
FIG. 2 is a partial cross-sectional view Or the panel
of this invention, taken along the line 2-2 of FIG. l;
FIG. 3 is a partial cross-sectional view of the panel
system of this invention, taken along the line 3-3 of FIG.
l; and,
FIG. 4 is a perspective view of still another embodiment
of the panel Or this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
This invention may be more fully described, but is not
intended to be limited, by reference to the disclosed preferred
embodiments illustrated in the attached drawings wherein:
a sound absorbing material 11 is shown completely enclosed
within a heat shrunk plastic material 12, and in FIG. 4,
supported by a frame 13 extending about the outer edge Or
the enclosed sound absorbing material, with the frame in
this embodiment having a U-shaped cross-section. In FIG. 1,
two panel sections are shown, one placed on top of the
other, with the lower edge of one abutting the upper edge of
the other. A frame 14 completely encircles the two abutting
sections. The frame 14 has a U-shaped cross-section. A web
is provlded for supporting the panel sections at their
abuttlng edges, with the web comprising web members 15 and
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16 placed baclc to bacl; t;o form a web having an ~I-shape(l
cross-section. In the embodiment illustrated in ~ . 1, one
face of the enclosed sound absorbing material is covered by
a perforated ~acing 17, ~nd the other face of the sound
absorbing material is covered with a solid facing 18. It
must be understood, however, that the facings are not required
and can be any of the embodiments hereinbefore discussed
with reference to this invention.
While only several forms and embodiments of the invention
have been shown and described, other forms and embodiments
with the spirit and scope of the invention will become
apparent to those skilled in the art. Therefore, the forms
and embodiments shown in the drawings are to be considered
as merely setting forth the invention for illustrative
purposes and are not intended to limit the scope of the
invention herein described and shown.
It may thus be seen that this invention provides the
first highly adaptable sound absorbing system which is low
in cost, and which, additionally, overcomes all of the
problems associated with prior panel systems. It is also
the first known sound absorbing panel which can be adapted
to any known need of sound absorbing panel systems. It is
significant when any invention in the construction industry
provides such an extensive adaptability to any required use.
This new and novel invention, therefore, significantly
advances sound control technology.
Having fully described this new and unique invention,
the following is claimed:
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