Note: Descriptions are shown in the official language in which they were submitted.
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INSULATION PROCESS
STATEMENT OF PRIORITY
This application claims the priority of U.S. Provisional Application No.
60/584,584 filed July 1, 2004, the contents of which are hereby incorporated
by reference.
FIELD
This invention relates to processes for providing thermal and/or acoustic
shielding to, for example, transportation vehicles such as aircraft.
BACKGROUND
Thermal and/or acoustic insulation is widely employed in a variety of
applications. Such insulation provides enhanced comfort and improved
efficiency in
certain common vehicle uses (for example, in air conditioning and acoustically
insulating
automobiles) and is critical to the proper operation of other vehicles (for
example, in
maintaining a temperature gradient in high-flying aircraft).
The insulation installed in many of today's vehicles must meet very stringent
thermal and acoustic insulation requirements. As a result, the insulation
material is often
tightly packed into constricted areas and around many objects to ensure
maximum
insulation. The insulation must also perform under a wide range of
environmental
conditions. These demands are particularly strict in the design of aircraft,
which regularly
undergo dramatic temperature, pressure, and humidity changes.
Complicating the process of insulating vehicles is the fact that their shells
often
contain numerous obstructions (for example, pipes, stringers, tubes, and
structural ribs)
that the insulation material must be fitted around. The insulation also needs
to be
removable to permit inspection, maintenance, and repair (for example,
inspection for
corrosion and other problems). Thus, to accommodate obstructions and to enable
easy
removal, the insulating material is, particularly in the aircraft industry,
generally custom
cut to size and fitted with a custom cover to form a customized insulation
blanket.
Such production methods are highly labor intensive and slow, and the resulting
customized blankets ("custom parts") typically must be assigned individual
part numbers
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that require tracking during manufacture and storage. At the time of
installation in a
vehicle, the custom parts must then be matched with the locations within the
vehicle that
correspond to the custom parts in size and shape. Since a typical large
passenger jet
aircraft, for example, can have over 1300 differently-sized and/or differently-
shaped
pieces of insulation, the costs of such customization and its accompanying
tracking can be
substantial.
SUMMARY
Thus, we recognize that there is a need for vehicle insulation processes (and,
in
particular, processes for insulating aircraft) that make use of insulation
articles that can be
easily manufactured and installed (for example, without the need for tracking
systems to
match customized articles to particular locations within a vehicle), and that
can be easily
removed from the vehicle (for example, to enable article repair or replacement
and/or
vehicle maintenance or repair).
Briefly, in one aspect, this invention provides such a process, which
comprises
providing a vehicle with an insulation system comprising a plurality of
location-
interchangeable, insulation articles that are substantially identical in size
and shape. The
vehicle can be, for example, an automobile, truck, train, boat, ship, or
aircraft (preferably,
an aircraft; more preferably, a commercial aircraft; most preferably, a
commercial jet that
has a passenger capacity of at least about 100).
As used herein, "location-interchangeable" means that the insulation articles
can be
used in more than one location within a vehicle and are not customized in size
or shape to
match surfaces (or spaces) that have particular sizes and shapes. Rather, the
articles are of
a standard size and shape, such that a plurality (that is, at least two) of
the articles can be
used (instead of a single, larger, customized article) to collectively cover
surfaces (or fill
spaces) of varying shapes and sizes. The articles are "substantially
identical" in size and
shape (that is, sufficiently identical in size and shape, in accordance with
typical
manufacturing tolerances, to enable the substitution of one for another in
carrying out the
process of the invention).
The insulation system can further comprise other components (for example,
insulation articles of a limited number of other standard shapes and/or
sizes). When the
vehicle is an aircraft, the insulation system is preferably provided to at
least a major
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portion of the interior surface of the exterior skin of the aircraft, or to at
least a major
portion of the exterior surface of the interior compartments of the aircraft.
Alternatively,
one or more of the interior panels of the aircraft can comprise a plurality of
the articles.
It has been discovered that vehicle insulation systems and processes can be
simplified by using a "building block" approach in which a plurality of
insulation articles
of a single standard shape and size are used to build up larger patterns
having shapes that
correspond with those of the various spaces to be insulated. This eliminates
the need for a
multitude of customized insulation articles, as well as the need for expensive
and time-
consuming tracking systems for article manufacture, storage, and installation.
Furthermore, since the insulation articles are of a standard shape and size,
they can
be readily available to meet insulation repair and/or replacement needs. The
articles can
retain the removability characteristics of the customized articles, and, thus,
at least some
embodiments of the process of the invention meet the need for more cost-
effective vehicle
insulation processes that enable both easy installation and easy removal.
DETAILED DESCRIPTION
Insulation Articles
Insulation articles that can be used in carrying out the process of the
invention
include any of the materials (for example, fiberglass) and/or articles (for
example,
insulation blankets) that can be used to provide thermal and/or acoustic
shielding.
The insulation articles can comprise, for example, fibrous insulation, foam
insulation,
vacuum-based insulation, glass bubble-based insulation, or combinations
thereof.
Preferably, the insulation articles comprise fibrous insulation, vacuum-based
insulation, or
combinations thereof (more preferably, the articles comprise vacuum-based
insulation).
Such materials can be manufactured by known methods. Suitable fibrous
materials
include, for example, fiberglass and the melt blown fibers comprising
polypropylene that
are commercially available from 3M Company of St. Paul, MN under the trade
designation THINSULATE. Fibrous insulation can be provided in the form of a
lofty non-
woven layer or mat in which the fibers are entangled with or bonded to each
other. Such
mats can be prepared according to conventional techniques such as melt
blowing, air
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laying, or carding. The mats can be made with thermobonding fibers and exposed
to heat
to cause the thermobonding fibers to soften and bind at least some of the
fibers together.
An example of a useful lofty nonwoven mat is described in U.S. Pat. No.
4,837,067 (Carey et al.), the description of which is incorporated herein by
reference. As
described therein, the mat consists of a combination of entangled staple
fibers and bonding
staple fibers where the bonding fibers have, for example, a core of
polyethylene
terephthalate surrounded by a sheath of an adhesive polymer formed from
isophthalate and
terephthalate esters.
Other known insulation constructions can also be utilized including, for
example,
the thermally insulating sheet material described in U.S. Pat. No. 4,136,222
(Jonnes), the
description of which is incorporated herein by reference.
The insulation articles used in the process of the invention can be in the
form of a
panel or a mat or bat of insulation material, or, alternatively, the articles
can optionally
further comprise protective layers or even a protective casing or bag (for
example,
comprising polymer film) that substantially or even fully encloses the
insulation material.
The layers and/or bag can be either flexible, semi-rigid, or rigid. The
insulation material
can optionally be treated (for example, with silicones or fluorochemicals as
topical
treatments or polymer melt additives) to increase its hydrophobicity.
The insulation articles can comprise one or more layers of insulation
material. In
addition, other materials and layers conventionally found in insulation
blankets can be
included. For example, the article can further comprise one or more high-
temperature
resistant materials (including, for example, materials that are resistant to
flame
propagation and/or flame penetration), one or more adhesive compositions or
films, one or
more scrims (for example, woven or nonwoven material or netting), one or more
water
repellent coatings, one or more intumescent additives or coatings, one or more
reflective
films (for example, for controlling radiant energy), and one or more polymer
films (which
can optionally be metallized), as well as flame retardants, antistatic agents,
anti-mildew
agents, and the lilce.
The above-described insulation articles can be manufactured by known methods
and can further comprise one or more attachment devices for use in attaching
the articles
to each other and/or to the vehicle. Useful attachment devices include
adhesives (for
example, pressure-sensitive adhesives or non-tacky adhesives), re-closable
fasteners (for
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example, hook and loop fasteners), mechanical interlocks (for example, tongue
and
groove, buttons and button holes, snaps, and shaped "puzzle-like" edges or
structures),
clips, pins, and the like, and combinations thereof. The attachment devices
are preferably
an integral part of the article, but separate attachment devices can be
utilized, if desired.
The articles can be of any shape and size that facilitates coverage of a
vehicle
surface. Representative examples of usefully shaped articles include spherical
articles and
"two-dimensional" panels or sheets or thicker versions thereof (three-
dimensional
"solids") that are, for example, square (six faces), rectangular (six faces),
triangular (five
faces), hexagonal (eight faces), octagonal (ten faces), doughnut-shaped, and
the like. The
particular shape and size of the articles that are chosen for carrying out the
process of the
invention will vary, depending, for example, upon the size of the vehicle and
its surface
configurations. However, rectangular shapes (rectangular solids) can sometimes
be
preferred, due to their versatility.
Insulation System and Process
Although the process of the invention utilizes the above-described primary
insulation articles (or "building blocks") of a single shape and size to
"build up" a thermal
and acoustic insulation system, useful insulation systems can further comprise
other
components such as supplementary insulation articles of a limited number of
other
standard shapes or sizes. For example, large open sections of a vehicle
(preferably, an
aircraft) can be insulated using the primary insulation articles, and smaller
areas can be
insulated using smaller supplementary insulation articles. The shapes can be
selected for
optimum packing geometry to allow installation around surface protrusions with
minimal
or no gaps.
Preferably, the supplementary insulation articles are of the same shape as the
primary insulation articles (differing only in size). The supplementary
insulation articles
can be differently-shaped, however, although the insulation system generally
contains no
more than about 100 different shapes in total (preferably, no more than about
50; more
preferably, no more than about 20; most preferably, no more than about 10).
The
insulation articles of each particular shape can vary in size, but the total
number of sizes of
each different shape generally does not exceed about 100 (preferably, does not
exceed
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about 50; more preferably, does not exceed about 20; most preferably, does not
exceed
about 10).
The vehicle can be provided with the insulation articles in any desired manner
(for
example, by bringing the articles in or on the vehicle or one or more of its
components, for
example, by placement, application, or attachment). Thus, the insulation
articles can, for
example, be attached to the vehicle and/or to each other to form the
insulation system.
This can be accomplished using any attachment device that is capable of use
with the
materials comprising the insulation articles and with the vehicle surface. For
example, the
insulation articles can be coated with a first adhesive that will adhere only
to itself and will
release when pulled upon. Such an adhesive generally cannot aggressively bind
dirt or
other contaminants. A second adhesive can be used to attach the insulation
articles to the
vehicle surface. Alternatively, mechanical or re-closable fastening systems
can be used to
attach the articles to each other, and an adhesive can be used to attach the
articles to the
vehicle surface.
When the insulation articles are in the form of panels or sheets, they can be
laid
down, for example, in an overlapping manner similar to the manner in which
roofing
shingles are laid down. Such overlap can reduce thermal and acoustic leakage
at the joints
between the insulation articles and increase the insulating properties of the
system. This
approach can facilitate installation in confined spaces and enable desirable
thermal and
acoustic properties to be achieved in such spaces. For such a system, adhesive
can be used
on one side of the panels or sheets for attachment both to the vehicle surface
and to other
panels or sheets. Mechanical or re-closable fasteners can also be used to hold
each sheet
to the one below.
In addition to the foregoing methods, numerous other possible methods of
providing the vehicle with the articles can be envisioned by the skilled
artisan. The
insulation process of the invention is particularly useful in insulating
aircraft by providing
(for example, applying or attaching) the insulation system to an area anywhere
between
and including (i) the interior surface of the exterior skin of the aircraft
and (ii) the exterior
surface of the interior compartments of the aircraft (including the underside
of the floor of
the passenger compartment). The insulation articles can be designed to be
flexible enough
to push around irregular shapes on the aircraft surface or can simply be
positioned to allow
wire penetrations, etc. For insulating the aircraft frame, the insulation
articles can be
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designed to be sufficiently stiff yet elastic to enable them to be snapped
into place over the
frame. Such insulation articles can insulate the frame and also provide
attachment sites for
the remainder of the insulation system.
Examples
Objects and advantages of this invention are further illustrated by the
following
examples, but the particular materials and amounts thereof recited in these
examples, as
well as other conditions and details, should not be construed to unduly limit
this invention.
Insulation Articles
Fiberglass Insulation Articles
Fiberglass insulating material in the form of Orcotekm Strip Blankets
(fiberglass
batting with an insulation covering film, available from Orcon Corporation,
Union City,
California) is used to prepare fiberglass insulation articles. The dimensions
of each article
are marked onto the top surface of the insulation covering film of the
OrcotekTm Strip
Blankets and then cut out. The cut edges are then sealed using OrcotapeTm OT-
54W (a
pressure sensitive, reinforced metallized polyvinyl fluoride tape, available
from Orcon
Corporation, Union City, California) to provide fiberglass insulation
articles.
Vacuum-Based Insulation Articles
Vacuum-based insulation articles are prepared by vacuum sealing a core of
INSTILL foam (a micro-cellular, open-cell polystyrene foam available from Dow
Chemical Company, Midland, Michigan) within a MylarTM SBL barrier film (a
multilayer,
polyester-based film having a metallized coating and heat sealable layers,
available from
Dupont Teijin FilmsTM, Hopewell, Virginia). A vacuum chamber equipped with a
thermal
sealing means is employed for this purpose, with the vacuum being
approximately 0.05
Torr. A desiccant is incorporated into each individual article.
Attachment Devices
Various attachment devices are employed to attach the insulation articles to a
vehicle to be insulated:
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Hook and Loop
3MTM ScotchmateTM Hook and Loop Reclosable Fasteners (for example, 3MTM
ScotchmateTM Reclosable Fastener SJ3530 (Hook) and 3MTM ScotchmateTM
Reclosable
Fastener SJ3531 (Loop), available from 3M Company, St. Paul, Minnesota) are
used. The
hook or loop system is attached to the insulation articles by stitching or by
using a
pressure sensitive adhesive (PSA). The corresponding (or mating) loop or hook
is
attached to the vehicle using a PSA.
Pressure Sensitive Adhesives
Natural rubber-based adhesives, synthetic rubber-based adhesives, and acrylic-
based adhesives are used, including 3MTM Adhesive Transfer Tape 468MP
(comprising an
acrylic type of adhesive, available from 3M Company, St. Paul, Minnesota).
The following examples are carried out using each possible combination of the
various insulation articles and attachment devices described above.
Example 1
Vehicle Insulation Process Using Abutting Insulation Articles
An area of a vehicle measuring 3 meters long by 1 meter wide is provided with
insulation articles having a rectangular geometry. The insulation articles are
placed in an
abutting arrangement, with no overlap and in a single layer. The thickness of
the
insulation articles is selected to meet the performance requirements of a
desired
application.
The rectangular insulation articles are of three different sizes, measuring 1
meter
long by 1 meter wide, 1 meter long by 0.5 meter wide, and 0.5 meter long by
0.5 meter
wide. Thus, the area is insulated by attaching 3, 6, or 12 insulation
articles, respectively,
to the area using attachment devices. Combinations of insulation articles of
the different
sizes are used to insulate an adjacent area of the same dimensions (3 meters
long by 1
meter wide).
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Example 2
Vehicle Insulation Process Using Overlapping Insulation Articles
Example 1 is repeated with the modification that the insulation articles are
positioned in an overlapping configuration (that is, a "shingled" relationship
analogous to
the laying of roof shingles). Attachment devices are employed to attach the
insulation
articles to the vehicle to be insulated and/or to the other insulation
articles.
The referenced descriptions contained in the patents, patent documents, and
publications cited herein are incorporated by reference in their entirety as
if each were
individually incorporated. Various unforeseeable modifications and alterations
to this
invention will become apparent to those skilled in the art without departing
from the scope
and spirit of this invention. It should be understood that this invention is
not intended to
be unduly limited by the illustrative embodiments and examples set forth
herein and that
such examples and embodiments are presented by way of example only, with the
scope of
the invention intended to be limited only by the claims set forth herein as
follows:
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