U.S. patent application number 14/964507 was filed with the patent office on 2017-06-15 for insulating material with renewable resource component.
This patent application is currently assigned to Whirlpool Corporation. The applicant listed for this patent is Whirlpool Corporation. Invention is credited to Mukherjee Diptesh, Rameet Singh Grewal, Manjur Tamboli.
Application Number | 20170167782 14/964507 |
Document ID | / |
Family ID | 59013108 |
Filed Date | 2017-06-15 |
United States Patent
Application |
20170167782 |
Kind Code |
A1 |
Diptesh; Mukherjee ; et
al. |
June 15, 2017 |
INSULATING MATERIAL WITH RENEWABLE RESOURCE COMPONENT
Abstract
An insulated cabinet structure includes an inner liner having a
plurality of walls defining a refrigerator compartment. An external
wrapper includes a plurality of walls defining a refrigerator
compartment receiving area. An insulation gap is formed between the
walls of the inner liner and the walls of the external wrapper when
the inner liner is received in the external wrapper. An insulation
member is positioned within the insulation gap and includes a
renewable resource component comprising about 10% to about 90% by
weight of the insulation member.
Inventors: |
Diptesh; Mukherjee; (Pune,
IN) ; Grewal; Rameet Singh; (Pune, IN) ;
Tamboli; Manjur; (St. Joseph, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Whirlpool Corporation |
Benton Harbor |
MI |
US |
|
|
Assignee: |
Whirlpool Corporation
Benton Harbor
MI
|
Family ID: |
59013108 |
Appl. No.: |
14/964507 |
Filed: |
December 9, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F25D 2201/122 20130101;
Y02B 40/00 20130101; F25D 2201/1262 20130101; F25D 23/063 20130101;
F25D 2201/14 20130101; F25D 23/066 20130101; F25D 2201/124
20130101; F25D 2201/128 20130101 |
International
Class: |
F25D 23/06 20060101
F25D023/06 |
Claims
1. An insulated cabinet structure comprising: an inner liner having
a plurality of walls defining a refrigerator compartment; an
external wrapper having a plurality of walls defining a
refrigerator compartment receiving area; an insulation gap formed
between the walls of the inner liner and the walls of the external
wrapper; and an insulation member positioned within the insulation
gap, wherein the insulation member includes a renewable resource
component comprising about 10% to about 90% by weight of the
insulation member.
2. The insulated cabinet structure of claim 1, wherein the
insulation member includes one or more insulation panels.
3. The insulated cabinet structure of claim 2, wherein each panel
of the one or more insulation panels includes a core portion and an
exterior portion surrounding the core portion.
4. The insulated cabinet structure of claim 3, wherein the
renewable resource component is disposed within the core portion of
the insulation panel.
5. The insulated cabinet structure of claim 4, wherein the
renewable resource component includes an open cell structure.
6. The insulated cabinet structure of claim 5, wherein the exterior
portion includes a closed cell structure.
7. The insulated cabinet structure of claim 6, wherein the exterior
portion includes a synthetic foam material.
8. The insulated cabinet structure of claim 7, wherein the
renewable resource component is an organic component selected from
the group consisting of rice hull ash, durian peel, palm leaves,
corn cobs, corn stalks, bagasse, coconut husks and rice husks.
9. The insulated cabinet structure of claim 2, wherein each panel
of the one or more insulation panels includes a vacuum formed
insulation panel having an internal pressure of about 100 mbar to
about 1000 mbar.
10. The insulated cabinet structure of claim 9, wherein each panel
exhibits a thermal conductivity value from about 20 mW/mK to about
22 mW/mK.
11. The insulated cabinet structure of claim 1, wherein the
insulation member includes one or more mold-formed insulated
blocks.
12. The insulated cabinet structure of claim 11, wherein the one or
more insulation blocks include the renewable resource component
combined with a cross-linked polymer.
13. The insulated cabinet structure of claim 1, wherein the
insulation member includes a polyurethane foam combined with the
renewable resource component.
14. A method of making an insulated cabinet, the method comprising
the steps of: forming an external wrapper having a cavity; forming
an inner liner having a refrigerator compartment; positioning the
refrigerator compartment of the inner liner within the cavity of
the exterior wrapper, thereby forming an insulation gap between the
inner liner and the external wrapper; providing a renewable
resource component; forming an insulation member using the
renewable resource component; and positioning the insulating member
in the insulation gap.
15. The method of claim 14, wherein the step of providing a
renewable resource component further includes: providing an amount
of rice husk material; and sizing the amount of rice husk material
to provide rice husk particles having a diameter of about 10 to
about 25 microns.
16. The method of claim 15, wherein the step of forming an
insulation member further includes: intermixing the rice husk
particles with a binder to form a mixture.
17. The method of claim 16, wherein the step of positioning the
insulating member in the insulation gap further includes: pouring
the mixture into the insulation gap.
18. The method of claim 15, wherein the step of forming an
insulation member further includes: forming a core using the
renewable component; and wrapping the core with an exterior portion
having a closed cell structure to form a hybrid insulation panel
insulating member.
19. The method of claim 15, wherein the step of forming an
insulation member further includes: intermixing the renewable
resource with one of a polyol component and an isocyanate
component; and spraying the polyol component and the isocyanate
component into the insulation gap to form a foam insulation.
20. A method of making an insulated cabinet, the method comprising
the steps of: forming an external wrapper having a cavity; forming
an inner liner having a refrigerator compartment; positioning the
refrigerator compartment of the inner liner within the cavity of
the exterior wrapper; forming an airtight insulation gap between
the inner liner and the external wrapper by sealing a portion of
the inner liner to a portion of the external wrapper; providing a
renewable resource component; forming an insulation member using
the renewable resource component; positioning the insulating member
in the insulation gap; and drawing a vacuum in the insulation gap.
Description
BACKGROUND
[0001] In order to provide increased efficiency for an insulated
appliance, such as a refrigerator cabinet, the refrigerator cabinet
must be sufficiently insulated to keep items within the
refrigerator cool, as well as prevent heat from entering the
refrigerator structure. Adding a renewable source component to an
insulation component while lowering the cost of the overall
refrigeration insulation is desired, such that new methods and
materials of insulating a refrigerator are sought.
SUMMARY
[0002] One aspect of the present concept includes an insulated
cabinet structure with an inner liner having a plurality of walls
defining a refrigerator compartment. An external wrapper includes a
plurality of walls defining a refrigerator compartment receiving
area. An insulation gap is formed between the walls of the inner
liner and the walls of the external wrapper. An insulation member
is positioned within the insulation gap, wherein the insulation
member includes a renewable resource component comprising about 10%
to about 90% by weight of the insulation member.
[0003] Another aspect of the present concept includes a method of
making an insulated cabinet including the steps of: I--forming an
external wrapper having a cavity; II--forming an inner liner having
a refrigerator compartment; III--positioning the refrigerator
compartment of the inner liner within the cavity of the exterior
wrapper, thereby forming an insulation gap between the inner liner
and the external wrapper; IV--providing a renewable resource
component; V--forming an insulation member using the renewable
resource component; and VI--positioning the insulating member in
the insulation gap.
[0004] Yet, another aspect of the present concept includes a method
of making an insulated cabinet including the steps of: I--forming
an external wrapper having a cavity; II--forming an inner liner
having a refrigerator compartment; III--positioning the
refrigerator compartment of the inner liner within the cavity of
the exterior wrapper; IV--forming an airtight insulation gap
between the inner liner and the external wrapper by sealing a
portion of the inner liner to a portion of the external wrapper;
V--providing a renewable resource component; VI--forming an
insulation member using the renewable resource component;
VII--positioning the insulating member in the insulation gap; and
drawing a vacuum in the insulation gap.
[0005] These and other features, advantages, and objects of the
present concept will be further understood and appreciated by those
skilled in the art upon studying the following specification,
claims, and appended drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] In the drawings:
[0007] FIG. 1A is a top perspective view of a refrigerator cabinet,
according to one embodiment;
[0008] FIG. 1B is an exploded top perspective view of the
refrigerator cabinet of FIG. 1A, according to one embodiment;
[0009] FIG. 2 is a cross-sectional view taken at line II of FIG.
1A;
[0010] FIG. 3 is a schematic depiction of a refrigerator cabinet
insulator filling system, according to one embodiment;
[0011] FIG. 4 is a schematic depiction of a refrigerator cabinet
insulator filling system, according to one embodiment;
[0012] FIG. 5 is an exploded view of an inner liner and external
wrapper, according to one embodiment;
[0013] FIG. 6 is a cross-sectional view of a refrigerator cabinet
having first and second insulation materials disposed in an
insulation gap;
[0014] FIG. 7 is a cross-sectional view of a refrigerator cabinet
having a plurality of insulation members disposed in an insulation
gap;
[0015] FIG. 8 is a cross-sectional view of a refrigerator cabinet
having a plurality of insulation panels disposed in an insulation
gap;
[0016] FIG. 9 is a graphical representation of a thermal
conductivity value relative to a pressure value;
[0017] FIG. 10 is a graphical representation of a thermal
conductivity value relative to a particle diameter;
[0018] FIG. 11 is a picture of rice husks and rice hull ash;
[0019] FIG. 12A is a perspective view of an insulation panel;
and
[0020] FIG. 12B is a cross-sectional view of the insulation panel
of FIG. 12A taken at line XII.
DETAILED DESCRIPTION OF EMBODIMENTS
[0021] For purposes of description herein the terms "upper,"
"lower," "right," "left," "rear," "front," "vertical,"
"horizontal," and derivatives thereof shall relate to the device as
oriented in FIG. 1A. However, it is to be understood that the
device may assume various alternative orientations and step
sequences, except where expressly specified to the contrary. It is
also to be understood that the specific devices and processes
illustrated in the attached drawings, and described in the
following specification are simply exemplary embodiments of the
inventive concepts defined in the appended claims. Hence, specific
dimensions and other physical characteristics relating to the
embodiments disclosed herein are not to be considered as limiting,
unless the claims expressly state otherwise.
[0022] Referring now to FIG. 1A, a refrigerator 10 is shown having
a cabinet 12 configured to generally define a refrigerator
compartment 14. As shown in FIG. 1A, the refrigerator 10 is
depicted as having a generally upright rectangular configuration,
but may include any configuration for refrigerator known in the art
including, but not limited to, French door, side-by-side, top
freezer, bottom freezer, freezer-less, counter depth, compact,
built-in, and other refrigerator configuration.
[0023] Referring now to FIG. 1B, the cabinet 12 is shown as
including an inner liner 16 which generally defines the
refrigerator compartment 14 via first and second sidewalls 18, 20,
top wall 22, and bottom wall 24. A rear wall 26 closes the
refrigerator compartment 14. A liner flange 28 is disposed around
the inner liner 16 and connected to the first and second sidewalls
18, 20, as well as the top and bottom walls 22, 24 along a front
portion of the inner liner 16, such that the liner flange 28
defines a forward face of the inner liner 16. In the depicted
embodiment of FIG. 1B, the inner liner 16 has a generally
rectangular box shape, but may take a variety of shapes including a
cube, prism, parallelepiped, etc. and combinations thereof to suit
a configuration of the refrigerator 10. The inner liner 16 may be
formed from a polymeric material having high barrier properties
(e.g., low gas permeation), metals and combinations thereof. The
inner liner 16 may be formed via thermoforming, injection molding,
bending and/or forming. The liner walls 18, 20, 22, 24 and 26 of
the inner liner 16 may have a thickness ranging from between about
0.1 mm to about 1.0 mm. In a specific embodiment, the liner walls
18, 20, 22, 24, and 26 are contemplated to have a thickness of
about 0.5 mm.
[0024] Referring again to FIG. 1B, the inner liner 16 is shown as
being configured to mate, couple, or otherwise be positioned within
an external wrapper 30. The external wrapper 30 includes first and
second sidewalls 32, 34, top wall 36, and bottom wall 38. A rear
wall 40 closes the refrigerator compartment. Thus, the external
wrapper 30 has an overall configuration similar to that of the
inner liner 16, such that the refrigerator compartment 14 of the
inner liner 16 can be fully received within a refrigerator
compartment receiving area 42 defined by the wrapper walls 32, 34,
36, 38 and 40. In a manner similar to the inner liner 16, the
external wrapper 30 includes a wrapper flange 44 extending around
the sidewalls 32, 34 and top and bottom walls 36, 38 at a forward
portion of the external wrapper 30.
[0025] In assembly, as shown in FIG. 2 and described below, the
wrapper flange 44 and the liner flange 28 are configured to be
coupled together to form the cabinet 12, as shown in FIG. 1A. The
coupling of the liner flange 28 and the wrapper flange 44 is
contemplated to be performed in such a manner that an airtight or
hermetic seal is formed between the inner liner 16 and the external
wrapper 30. The seal of the inner liner 16 to the external wrapper
30 may be achieved using adhesives, welding, crimping, or
combinations of such coupling techniques. The external wrapper 30
may be formed of and by any of the materials and processes listed
above in connection with the inner liner 16. The wrapper walls 32,
34, 36, 38 and 40 of the external wrapper 30 may have a thickness
ranging from between about 0.1 mm to about 1.0 mm. In a specific
embodiment, the wrapper walls 32, 34, 36, 38 and 40 have a
thickness of about 0.5 mm. Any one of the wrapper walls 32, 34, 36,
38 and 40 of the external wrapper 30 may include an injection port
50 and/or a vacuum port 52, shown in FIG. 1B as disposed on top
wall 36 and sidewall 34, respectively. The external wrapper 30 may
include one or multiple injection ports 50 and/or vacuum ports 52.
It will be understood that in alternative embodiments, the
injection ports 50 and/or vacuum ports 52 may be disposed on both
the external wrapper 30 and inner liner 16, or solely on either the
inner liner 16 or external wrapper 30. The injection port 50 and
the vacuum port 52 may be used to access (e.g., to inject an
insulator, draw a vacuum and/or perform maintenance within) an
insulation gap 54 formed between the refrigerator compartment 14
and the refrigerator compartment receiving area 40 once the inner
liner 16 and the external wrapper 30 are bonded. The injection port
50 and the vacuum port 52 may have a diameter of between about 10
mm and about 30 mm, or between about 12.5 mm and about 25 mm. In
various embodiments, the injection port 50 and the vacuum port 52
may have different diameters than one another. Similarly, in
embodiments utilizing more than one injection port 50 and vacuum
port 52, the sizes of the injection ports 50 and the vacuum ports
52 may vary. The insulating material 80 is positioned within the
insulation gap 54 and in contact with both the wrapper walls 32,
34, 36, 38 and 40 and the liner walls 18, 20, 22, 24 and 26. The
packing factor of the insulating material 30 within the gap 26 may
be greater than about 60%, greater than about 62%, greater than
about 65%, or greater than about 70%.
[0026] The insulating material 80 is configured not only to
thermally insulate the inner liner 16 from the external wrapper 30,
but also to resist the inward directed force of the atmosphere on
the lower than atmosphere pressure of the insulation gap 54.
Atmospheric pressure on the inner liner 16 and the external wrapper
30 may cause distortions which are unsightly and may lead to a
rupture in either of the inner liner 16 or the external wrapper 30
thereby causing a loss of vacuum in the insulation gap 54. Further,
drawing the vacuum in the insulation gap 54 may cause an impact or
shock loading of the insulating material 80 as the inner liner 16
and the external wrapper 30 contract around the insulating material
80. Accordingly, the insulating material 80 should have sufficient
crush resistance to resist deformation of the inner liner 16 and
the external wrapper 30 due to a pressure gradient between the
atmosphere and an air pressure of the insulation gap 54. The
insulating material may also serve as a sound dampening mechanism
in assembly.
[0027] Referring again to FIG. 1B, an exterior shell 60 may also be
included in the formation of the cabinet 12, wherein the exterior
shell 60 includes first and second side walls 62, 64 as well as top
wall 66 and rear wall 68. The first and second sidewalls 62, 64 and
top wall 66 are configured to align with an outer perimeter of the
liner flange 28 and wrapper flange 44 as coupled together. The
exterior shell 60 generally defines a cabinet receiving area 70
which is configured to receive the inner liner 16 and external
wrapper 30 as coupled together therein.
[0028] Referring now to FIG. 2, the inner liner 16 and external
wrapper 30 are shown coupled together, such that the refrigerator
compartment 14 is received within the refrigerator compartment
receiving area 42, thereby defining the insulation gap 54
therebetween. The insulation gap 54 is configured to receive an
insulator material 80. The insulation gap 54 may have a thickness
of between about 12 mm to about 22 mm. The insulation gap 26 may
have an air pressure of less than about 1 atm (101,325 Pa), less
than about 0.5 atm (50,662.5 Pa), less than about 0.1 atm (10,132.5
Pa), less than about 0.001 atm (101.325 Pa) or less than about
0.00001 atm (1.01 Pa). The insulating material 80 may be a material
configured to have low thermal conductivity. For example, the
insulating material 80 may include precipitated silica,
polyurethane foam, fumed silica, beads (e.g., of glass, ceramic,
and/or an insulative polymer), hollow organic spheres, hollow
inorganic spheres, renewable materials, processed renewable
materials, and combinations thereof. Optionally, an opacifier
(e.g., TiO.sub.2m SiC and/or carbon black) may be included in the
insulating material 80 or materials configured to change the flow
properties and packing factor of the insulating material 80.
[0029] Referring now to FIG. 3, one embodiment of an apparatus and
method of inserting the insulating material 80 within the
insulation gap 54 is depicted. As shown in FIG. 3, the inner liner
16 is positioned within the external wrapper 30 as explained in
greater detail above. The liner flange 28 and the wrapper flange 44
are contemplated to be bonded so as to create an airtight
insulation gap 54 defined between the inner liner 16 and the
external wrapper 30. A vacuum is created by drawing the air out of
the insulation gap 54 through the at least one vacuum port 52,
wherein the vacuum provides a negative pressure relative to the
atmospheric pressure. A pump, or other suitable vacuum source, may
be connected to the vacuum port 52 to facilitate the drawing and
creation of the vacuum. Additionally, a vacuum chamber 90 may be
used to provide the vacuum to the insulation gap 54.
[0030] With further reference to FIG. 3, injecting the insulating
material 80 into the insulation gap 54 is contemplated to be
accomplished by feeding the insulating material 80 into a hopper 82
which in turn supplies the insulating material 80 to a powder pump
84. The powder pump 84 pumps or otherwise injects the insulating
material 80 into the insulation gap 54. The powder pump 84 may
utilize fluidization of the insulating material 80 to move the
insulating material 80 into the insulation gap 54. The powder pump
84 may dispense the insulating material 80 into the insulation gap
54 under or without pressure. Use of the powder pump 84 allows the
insulating material 80 to be inserted into the insulation gap 54
without any densification or compaction, while also providing an
efficient means of depositing the insulating material 80 in the
insulation gap 54. Vibration techniques may be used to vibrate the
inner liner 16 and/or the external wrapper 30 in an effort to
increase the packing factor of the cause the insulating material 80
as disposed within the insulation gap 54. The inner liner 16 and/or
external wrapper 30 may be supported by one or more supports 86,
such that relative motion between the inner liner 16 and the
external wrapper 30 is minimized or prevented. The supports 86 may
allow the thickness of the insulation gap 54 to remain constant
through filling and vibration.
[0031] Referring now to FIG. 4, another method of dispensing the
insulating material 80 within the insulation gap 54 between the
inner liner 16 and the external wrapper 30 is shown. In this
method, dispensing of the insulating material 80 into the
insulation gap 54 may be accomplished through an access aperture
92. The back aperture 92 may take a variety of shapes (e.g.,
square, rectangular, circular, oblong, and combinations thereof)
and sizes which are configured to allow the insulating material 80
to be poured or otherwise deposited into the insulation gap 54. The
insulating material 80 may be positioned in the insulation gap 54
between the inner liner 16 and the external wrapper 30 via a powder
pump, such as powder pump 84 described above with reference to FIG.
3. Further, the insulating material 80 may be positioned in the
insulation gap 54 by pouring a mixture containing the insulating
material 80 into the insulation gap 54. The insulating material 80
may be positioned in the insulation gap 54 by spraying a foaming
mixture containing the insulating material 80 into the insulation
gap 54. Further, the insulating material 80 may be positioned in
the insulation gap 54 by creating blocks or panels containing the
insulating material 80, and positioning these blocks and/or panels
in the insulation gap 54. Once the insulation gap 54 between the
inner liner 16 and the external wrapper 30 is filled with the
insulating material 80 and sufficiently packed, a cover 94 is
positioned over the access aperture 92. The cover 94 may be
constructed of the same or similar material as the external wrapper
30, or a different material. Once the cover 94 is positioned over
the access aperture 92, the cover 94 is sealed to the external
wrapper 30 to form an airtight, or hermetic, seal. With the
airtight seal in place, a vacuum can be drawn within the insulation
gap 54 in a manner as described above. The vacuum may be drawn
through the vacuum port 52 (FIG. 3) of the external wrapper 30.
Additionally, this method can also be conducted in a vacuum chamber
90.
[0032] Referring now to FIG. 5, another embodiment of a cabinet 12A
is shown in an exploded view with an inner liner 16A which
generally defines a refrigerator compartment 14. The inner liner
16A includes a number of components similar to inner liner 16
described above with like reference numerals, such as first and
second sidewalls 18, 20, top wall 22 and bottom wall 24. A rear
wall 26 closes the refrigerator compartment 14. A liner flange 28
is disposed around the inner liner 16A along a front portion
thereof. The cabinet 12A further includes an external wrapper 30A.
The external wrapper 30A includes a number of components similar to
external wrapper 30 described above with like reference numerals,
such as first and second sidewalls 32, 34, top wall 38 and rear
wall 40. Thus, the external wrapper 30A has an overall
configuration similar to that of the inner liner 16A, such that the
refrigerator compartment 14 of the inner liner 16A can be fully
received within a refrigerator compartment receiving area 42
defined by the wrapper walls 32, 34, 36 and 40. The external
wrapper 30A includes a wrapper flange 44 disposed at a forward
portion of the external wrapper 30A.
[0033] As further shown in FIG. 5, the sidewall 32 of the external
wrapper 30A includes an insulation member 102 disposed thereon.
Similarly, sidewall 34 and top wall 36 also include insulation
members 104, 106, respectively, disposed thereon, which are shown
in phantom in FIG. 5. Rear wall 40 of the external wrapper 30A also
includes an insulation member 108 disposed thereon. The insulation
members 102, 104, 106 and 108 are disposed on inwardly facing
surfaces, such that the insulation members 102, 104, 106 and 108
are configured to be disposed in the insulation gap 54 disposed
between the inner liner 16A and external wrapper 30A, as best shown
in FIG. 6.
[0034] As shown in FIG. 6, a cross-sectional view of the
refrigerator cabinet 12A separately illustrates three embodiments
for the insulation members, with insulation member 102 in a board
form, insulation member 104 in a powder form, and insulation member
108 as loose fiberglass. Each insulation member 102, 104 and 108
are shown covered by barrier sheets 112, 114, and 118 respectively.
The barrier sheets 112, 114, and 118 are contemplated to be
metallic foil sheets that can be formed from either a ferrous or
non-ferrous material. Of course, although a metallic material is
preferred, the barrier sheets 112, 114, and 118 can also be formed
from non-metallic materials without departing from the spirit of
the present concept. When placed upon the insulation members 102,
104 and 108, the sheets 112, 114, and 118 define upper surfaces
that protect the insulation members 102, 104 and 108 from water
vapor and other like destructive materials. When the refrigerator
cabinet 12A is assembled to form the insulation gap 54 (in which
the insulation members 102, 104 and 108 are disposed), a second
insulation material 122, preferably polyurethane foam, is
contemplated to be injected between each barrier sheet 112, 114,
and 118 and the outer walls of the inner liner 16A, such that a
composite insulation arrangement is formed. Once second insulation
material 122 cures, it will not only provide additional insulation
for the cabinet 12A, but it will add structural integrity thereto
as well. The second insulation material 122 may include silica or
other porous material capable of supporting the cabinet structure
when a vacuum is formed. It is further contemplated that the
insulation members 102, 104 and 108 may substantially fill the
entire insulation gap 54 on their own, such that a second
insulation material is not necessary. As further shown in FIGS. 5
and 6, evacuation tubes 120 are shown as coupled to each of the
insulation members 102, 104 and 108, and may be use to form a
vacuum around the insulation members 102, 104 and 108. While
insulation members 102, 104 and 108 are shown in FIG. 6 as having
varying forms, it is contemplated that the insulation members 102,
104 and 108 may also be of a similar form, such as an insulation
panel.
[0035] Referring now to FIG. 7, a cross-sectional view of another
refrigerator cabinet 12B is shown, wherein an inner liner 16B is
coupled to an external wrapper 30B to form an insulation gap 54
therebetween. Insulation members 124 are shown disposed in the
insulation gap 54 to insulate the refrigerator compartment 14. The
insulation members 124 shown in FIG. 7 are contemplated to be
insulation blocks formed from a multi-component insulating material
in a press or mold forming process, as further described below.
[0036] Referring now to FIG. 8, a cross-sectional view of another
refrigerator cabinet 12C is shown, wherein an inner liner 16C is
coupled to an external wrapper 30C to form an insulation gap 54
therebetween. Insulation members 126, 128 and 130 are shown
disposed in the insulation gap 54 to insulate the refrigerator
compartment 14 defined by the cabinet 12A. The insulation members
126, 128 and 130 are shown in FIG. 7 as insulation panels having
core portions 126A, 128A and 130A disposed within outer portions
126B, 128B, 130B to form multi-component insulating structures with
varying properties between the cores 126A, 128A and 130A and outer
portions 126B, 128B, 130B, as further described below.
[0037] The insulating materials used for the present concepts will
now be described. As noted above, the insulation material used with
the present concept is contemplated to provide a renewable
resource, or environmentally friendly resource, as a component part
of the insulation composition. This measure not only provides for
more environmentally friendly insulating practices, but also can
save on the costs involved in properly insulating a refrigerator
cabinet as compared to standard polyurethane foams. Specifically,
the cost of an insulation made with a renewable resource may cost
about $0.10 per kilogram as compared to about $2.419 per kilogram
of polyurethane foam. Often times the insulation made with the
renewable resource exemplifies a similar insulating property or may
include only a 5% heat gain as compared to polyurethane foam
materials. As used herein, the terms "renewable resource component"
or "renewable resource" refer to filler materials that are
eco-friendly materials, such as an organic material, a biomass
material, a natural waste by-product of a particular industry, or
other like naturally occurring component.
[0038] One renewable resource contemplated for use as an organic
component of the insulating materials of the present concept are
rice husks or rice hulls which are the hard protective outer
coverings of grains of rice. Rice husks are a thermal insulating
material comprised of approximately 70-75% silica. Using thermal
treatments, the silica percentage in rice husks can be increased to
approximately 90-98%. Silica is a known compound that is one of the
better insulators used in vacuum insulation panels and other high
performance thermal insulation applications. Preparing rice husks
for use in an insulation material may include the following
steps:
[0039] 1) washing rice husks in distilled water;
[0040] 2) drying the rice husks in hot air at 60 degrees Celsius
for approximately sixty minutes;
[0041] 3) sizing the rice husks using an industrial grinder;
[0042] 4) mixing rice husks with a binding resin at a ratio of
approximately 2:1 rice husks to resin by weight;
[0043] 5) stirring the rice husks in biding resin to properly mix
the composition;
[0044] 6) comparing insulating blocks using a press and mold with
the composition; or
[0045] 7) preparing panels for use as vacuum insulation panels with
the composition.
The rice husk, or a composition containing rice husks, may be
passed through a sieve of about 10 microns to about 25 microns to
achieve a particle size optimal for using rice husks as a renewable
resource component in an insulating material. With a rice husk
particle size of about 10 microns to about 25 microns, a thermal
conductivity value of approximately 20-22 mW/mK is achieved as
compared to a standard polyurethane foam having a thermal
conductivity value of about 17.5 mW/mK to about 20.5 mW/mK.
[0046] Coconut husks are also a renewable resource considered for
use with the insulating materials of the present concept. Like the
rice husks, coconut husks are a good thermal insulating material
because they are difficult to burn and less likely to allow
moisture to propagate mold and fungi in an application.
Historically, coconut husks have been used in making insulation
boards using a urea formaldehyde resin. In order to eliminate this
synthetic resin, it is contemplated that the present concept will
use lignin in the coconut husks as an intrinsic resin in board
production, thereby eliminating the need for chemical binders and
other additives. A insulating product using coconut husks may
exhibit insulating properties in a range of about 54-143 mW/Mk.
[0047] Another renewable resource contemplated for use with the
present concept are corn cobs and corn stalks. Corn cobs and corn
stalks can be used to make particle boards and fiber boards and
have been tested for use as raw materials for low density boards
made using a hot press method along with a urea formaldehyde resin.
Such boards exhibit a high mechanical strength and have a thermal
conductivity of approximately 96 mW/mK.
[0048] Another renewable resource contemplated for use with the
present concept is durian peel. Durian peel is the outer covering
of a durian fruit, and is a waste product of the durian industry.
Particle boards made using a durian peel have exhibited a thermal
conductivity in the range of approximately 64-159 mW/mK.
[0049] Another renewable resource contemplated for use with the
present concept is bagasse. Bagasse is the crushed and processed
cane stalk of sugar cane that is left when the juice is collected
from a sugar cane harvest. Bagasse is a waste produce of the sugar
cane industry that can be used as a raw material for making medium
density fiber boards or particle boards, as well as high density
hard boards. Bagasse can be further fortified using a phenolic
resin, thereby producing boards and panels that are strong and
durable, as well as heat and moisture resistant. These boards can
be lightweight and easily transportable and exhibit thermal
conductivity properties suitable for use with the present concept
in a thermal conductivity range of about 46-51 mW/mK.
[0050] Another renewable resource contemplated for use with the
present concept is a by-product from the palm oil production
process. Oil palm leaves include large amounts of ligno-cellulose
having a high fiber yield and are known for use in making composite
panels and particle boards. Such a composite panel may have a
thermal conductivity of approximately 127 mW/mK made by mixing oil
palm leaves with granular wood glue in a 1:4 ratio by weight. The
present concept is contemplated to use the ligno-cellulose
component of the oil palm leaves to make a binder free fiber board
using a steam expulsion method. Such a resulting insulating
material would be environmentally friendly by not incorporating a
toxic glue, and would also provide insulating properties similar to
those of an insulation panel made by mixing oil palm leaves with
wood glue. The above-identified organic components are integrated
into insulation products to provide a renewable resource component
within the product.
[0051] Processes for incorporating a renewable resource component
into an insulating material will now be described, and
particularly, rice husks are identified below as the incorporated
renewable resource, however, it is contemplated that any of the
renewable resources noted above can be used with the methods
described below. The first method of incorporating a renewable
resource into an insulating product is the mixing of the renewable
resource component with the components of a polyurethane foam. In
this concept, rice husks and polyurethane foam are mixed in
optimized ratios to deliver improved thermal insulating properties
as compared to a rice husk insulation alone. Mixing the rice husk
with a polyurethane foam eliminates the need for additional binder
as the component parts of a polyurethane foam will act as a binder
in the mixing process. The polyurethane form also adds structural
rigidity as compared to rice husk insulation alone. In making a
standard polyurethane foam, isocyanate and polyols are mixed
generally in a spraying process to create a urethane foam.
Processed rice husks having a particle size of approximately 10-25
microns can be incorporated into either the isocyanate mixture or
the polyol mixture before they are combined to form a urethane.
Further, the processed rice husks can be combined with the
isocyanate and polyol mixture immediately after the isocyanate and
polyol components are mixed. Using the present concept, it is
contemplated that a resulting polyurethane foam would contain
approximately 10-90 percent or 40-60 percent by weight of the rice
husk mixture which would be distributed uniformly throughout the
resulting polyurethane foam. The addition of the rice husk in the
polyurethane foam provides for a lower cost product that is lighter
than the polyurethane foam alone. Further, as noted above, the
processed rice husk component will reduce the costs of the overall
insulating product. Similarly, the rice husks can be mixed with
other synthetic closed cell insulation products, such as
cyclopentane foam products and are contemplated to exhibit
comparable compression strengths as compared to such products made
without a renewable component.
[0052] Another method involves providing a mixture of a renewable
resource with a binder, wherein the resulting mixture is poured
into an insulation gap, such as insulation gap 54 described above,
for forming an insulating product that can fill the insulation gap
in a cabinet. This method provides for environmentally friendly
insulation without any polyurethane foam, such that the cost of the
resulting insulation product are reduced. In this concept,
processed rice husk particles of approximately 10-25 microns are
mixed with a resin, such as an epoxy resin, for forming a pourable
mixture. Suitable epoxy resins include epoxy cements, cross-linked
polyvinyl alcohol and polyacrylamide and other cross-linked
polymers that will not compact or densify the processed rice husk
when mixed therewith. The resulting mixture can be poured into an
insulation gap, such as insulation gap 54 shown in FIG. 4 using
access aperture 92.
[0053] Another method used with the present concept is to use
processed rice husks as packed in insulation panels which are then
vacuumed. This concept involves using processed rice husks instead
of fumed silica, glass fibers or precipitated silica. The resulting
product provides for an insulation material that does not require
additional binder and is less expensive than a standard
polyurethane foam. A variation of thermal conductivity as it
relates to internal pressure of such an insulation panel is noted
below in Table 1.
TABLE-US-00001 TABLE 1 Internal Pressure (mbar) Thermal
Conductivity (mW/mK) 1000 22.0 500 21.8 100 20.3 50 18.7 10 12.3 5
9.4 1 5.6
[0054] The values noted in Table 1 above are also shown in FIG. 9
of the present disclosure.
[0055] Another method of using a renewable resource with an
insulating product of the present concept is to create an
insulating product having a polyurethane foam blanket or outer
portion wrapped around a core portion created using a renewable
resource. As noted above, and further shown in FIG. 10, the
particle size of the rice husks used with the present concept is
contemplated to be between 10 and 25 microns. As shown in FIG. 10,
a particle diameter of 10-25 microns results in a thermal
conductivity value of approximately 22-22.2 mW/mK. Rice husks have
an open cell structure, such that an insulating product prepared
using rice husk alone is susceptible to increased thermal
conductivity when exposed to water vapor or water permeation
through a liner or wrapper in a refrigerator cabinet. This is
because as water vapor, or any other moisture source, is exposed to
the open cell structure of a rice husk, the water can be absorbed
by such an insulating product, thereby increasing the solid
conduction of the rice husk insulation product. With an increase in
thermal conductivity of such a rice husk insulation product, the
thermal performance of a refrigerator or insulation box may be
compromised. Thus, a polyurethane foam blanket around a rice husk
prepared core would provide a closed cell structure for an outer
portion of a panel (or other like structure) that will not allow
water vapor to permeate inside into the rice husk core. The rice
husk core may be a powered insulation used in the process described
above with reference to FIG. 3, wherein a powered product is
injected into the insulation gap 54 of a cabinet 12. With reference
to FIG. 8, the rice husk insulation would generally comprise a core
portion 126A having an open cell configuration susceptible to
higher thermal conductivity when exposed to water vapor. As further
shown in FIG. 8, the core portion 126A is wrapped by an outer
covering 126B which is contemplated to be comprised of a
polyurethane foam which is a closed cell structure that will not
allow water permeation, such that the core portion 126A retains its
insulating properties. As noted above, a rice husk insulation
product is less expensive than a standard polyurethane product,
such that a panel having a rice husk insulating core wrapped by a
polyurethane blanket, will result in an overall panel that is less
expensive than a standard closed cell panel made entirely of
polyurethane products.
[0056] Another renewable resource contemplated for use with the
present concept is a rice husk by-product created when using rice
husks as a fuel in rice mills to generate steam. As noted above,
the rice husk is a by-product of the rice milling process, wherein
the hard exterior shell surrounding a grain of rice is removed. The
rice husk (also known as a rice hull or shell) is shown in FIG. 11
and identified as RH. During a rice milling process, approximately
22 percent by weight of a paddy is received as husk that is used as
fuel to generate steam for a parboiling process. The husk contains
about 75 percent organic volatile matter that is consumed during
the process, and the remaining 25 percent of the husk is converted
into ash during the firing process. The ash is known as rice hull
ash as shown in FIG. 11 and identified as RHA. Rice hull ash
contains around 85-90 percent amorphous silica. It is contemplated
that for every 1000 kilograms of paddy milled, about 220 kilograms
of husk is produced. When this husk is consumed as fuel in the
parboiling process, about 55 kilograms of rice hull ash is
generated. With the amorphous silica content of the rice hull ash,
the rice hull ash is a suitable thermal insulator for use with the
present concept as a renewable resource component.
[0057] Rice husk ash can be mixed with a polyurethane foam in a
manner similar to the mixture of rice husks with a polyurethane
foam described above. Further, the rice husk ash may be mixed with
an epoxy that is poured into an insulation gap in a manner as
described above with reference to rice husks and epoxy resin
mixtures used in an insulation gap, such as insulation gap 54. The
rice husk ash can also be used in a vacuum to create an insulation
panel in a manner similar to that described above where a rice husk
is ground and packed in a panel and subsequently vacuumed. As
compared to polyurethane foam, rice hull ash insulation has a cost
of approximately $0.40 per kilogram, which is substantially less
than the $2.419 per kilogram for a polyurethane foam product.
[0058] Referring now to FIG. 12A, an insulation panel 140 is shown
having a body portion 142. The insulation panel 140 shown in FIG.
12A has a generally rectangular shape, but may include any shape
necessary for use in an insulated cabinet structure. The insulation
panel 140 may be used as an insulation member in a cabinet in a
manner similar to as insulation members 102, 104 and 108 shown in
FIG. 6, or insulation members 126, 128 and 130 shown in FIG. 8. The
insulation panel 140 may be a homogenous panel comprised entirely
of a renewable resource, or may be a hybrid panel having both
synthetic and renewable resource components. In one embodiment of a
hybrid panel, it is contemplated that the renewable resource
component will comprise about 10-90% or 40-60% of the panel by
weight of the panel, and be substantially evenly dispersed
throughout the body portion 142 of the panel 140. In another
embodiment of a hybrid panel, it is contemplated that the body
portion 142 will include a core portion 144 disposed within an
interior of the body portion 142, as shown in FIG. 12B. In FIG.
12B, the core portion 144 is surrounded by an exterior portion or
outer cover 146. In a manner similar to the insulating members 126,
128 and 130 described above with reference to FIG. 8, the core
portion 144 of the panel 140 may have a different cell structure as
compared to the external portion 146. Thus, the core portion 144
may have an open cell structure of a renewable resource component
disposed therein, and the external portion 146 of the panel 140 may
have a closed cell structure providing a vapor barrier to the open
cell core portion 144. The core portion 144 may be 100% comprised
of a renewable resource component, such as ground or processed rice
husks, durian peel, coconut husks, corn cob, corn stalk, bagasse,
oil palm leaves or rice hull ash. The renewable resource component
may also be somewhere in a range of about 10-90% of the core
portion after being combined with a binder resin. These renewable
components are contemplated to replace more costly synthetic
materials, such as fumed silica, precipitated silica, aerogel,
filler beads, micro-spheres, glass fibers, or glass bubbles. The
panel 140 is contemplated for use in a vacuum insulation panel
system within an insulated cabinet.
[0059] Using the techniques and materials described above, a method
of making an insulated cabinet 12 is disclosed, wherein the method
includes the steps of: I--forming an external wrapper 30 having a
cavity 42; II--forming an inner liner 16 having a refrigerator
compartment 14; III--positioning the refrigerator compartment 14 of
the inner liner 16 within the cavity 42 of the exterior wrapper 30,
thereby forming an insulation gap 54 between the inner liner 16 and
the external wrapper 30; IV--providing a renewable resource
component; V--forming an insulation member (80, 102, 124, 126)
using the renewable resource component; and VI--positioning the
insulating member (80, 102, 124, 126) in the insulation gap 54.
[0060] Another method of making an insulated cabinet 12, includes
the steps of: I--forming an external wrapper 30 having a cavity 42;
II--forming an inner liner 16 having a refrigerator compartment 14;
III--positioning the refrigerator compartment 14 of the inner liner
16 within the cavity 42 of the exterior wrapper 30; IV--forming an
airtight insulation gap 54 between the inner liner 16 and the
external wrapper 30 by sealing a portion 28 of the inner liner 16
to a portion 44 of the external wrapper 30; V--providing a
renewable resource component; VI--forming an insulation member (80,
102, 124, 126) using the renewable resource component;
VII--positioning the insulating member (80, 102, 124, 126) in the
insulation gap 54; and drawing a vacuum in the insulation gap
54.
[0061] It will be understood by one having ordinary skill in the
art that construction of the described device and other components
is not limited to any specific material. Other exemplary
embodiments of the device disclosed herein may be formed from a
wide variety of materials, unless described otherwise herein.
[0062] For purposes of this disclosure, the term "coupled" (in all
of its forms, couple, coupling, coupled, etc.) generally means the
joining of two components (electrical or mechanical) directly or
indirectly to one another. Such joining may be stationary in nature
or movable in nature. Such joining may be achieved with the two
components (electrical or mechanical) and any additional
intermediate members being integrally formed as a single unitary
body with one another or with the two components. Such joining may
be permanent in nature or may be removable or releasable in nature
unless otherwise stated.
[0063] It is also important to note that the construction and
arrangement of the elements of the device as shown in the exemplary
embodiments is illustrative only. Although only a few embodiments
of the present innovations have been described in detail in this
disclosure, those skilled in the art who review this disclosure
will readily appreciate that many modifications are possible (e.g.,
variations in sizes, dimensions, structures, shapes and proportions
of the various elements, values of parameters, mounting
arrangements, use of materials, colors, orientations, etc.) without
materially departing from the novel teachings and advantages of the
subject matter recited. For example, elements shown as integrally
formed may be constructed of multiple parts or elements shown as
multiple parts may be integrally formed, the operation of the
interfaces may be reversed or otherwise varied, the length or width
of the structures and/or members or connector or other elements of
the system may be varied, the nature or number of adjustment
positions provided between the elements may be varied. It should be
noted that the elements and/or assemblies of the system may be
constructed from any of a wide variety of materials that provide
sufficient strength or durability, in any of a wide variety of
colors, textures, and combinations. Accordingly, all such
modifications are intended to be included within the scope of the
present innovations. Other substitutions, modifications, changes,
and omissions may be made in the design, operating conditions, and
arrangement of the desired and other exemplary embodiments without
departing from the spirit of the present innovations.
[0064] It will be understood that any described processes or steps
within described processes may be combined with other disclosed
processes or steps to form structures within the scope of the
present device. The exemplary structures and processes disclosed
herein are for illustrative purposes and are not to be construed as
limiting.
[0065] It is also to be understood that variations and
modifications can be made on the aforementioned structures and
methods without departing from the concepts of the present device,
and further it is to be understood that such concepts are intended
to be covered by the following claims unless these claims by their
language expressly state otherwise.
[0066] The above description is considered that of the illustrated
embodiments only. Modifications of the device will occur to those
skilled in the art and to those who make or use the device.
Therefore, it is understood that the embodiments shown in the
drawings and described above is merely for illustrative purposes
and not intended to limit the scope of the device, which is defined
by the following claims as interpreted according to the principles
of patent law, including the Doctrine of Equivalents.
* * * * *