U.S. patent application number 10/997469 was filed with the patent office on 2005-09-01 for insulated panels and shipping container incorporating said panels.
Invention is credited to Chin Thiam, Yeo, Koh Ping, Hong, Xiaohai, Mao.
Application Number | 20050189404 10/997469 |
Document ID | / |
Family ID | 34793526 |
Filed Date | 2005-09-01 |
United States Patent
Application |
20050189404 |
Kind Code |
A1 |
Xiaohai, Mao ; et
al. |
September 1, 2005 |
Insulated panels and shipping container incorporating said
panels
Abstract
The invention relates to an insulation panel for use in
thermally insulated shipping containers, the panel comprising a
rigid core of an insulation material, the core being wholly
encompassed within a polyethylene foam envelope. A container made
from the panels and a shipping carton is also described.
Inventors: |
Xiaohai, Mao; (Singapore,
SG) ; Chin Thiam, Yeo; (Singapore, SG) ; Koh
Ping, Hong; (Singapore, SG) |
Correspondence
Address: |
PATTERSON, THUENTE, SKAAR & CHRISTENSEN, P.A.
4800 IDS CENTER
80 SOUTH 8TH STREET
MINNEAPOLIS
MN
55402-2100
US
|
Family ID: |
34793526 |
Appl. No.: |
10/997469 |
Filed: |
November 24, 2004 |
Current U.S.
Class: |
229/103.11 ;
220/592.2; 220/592.25; 220/592.26 |
Current CPC
Class: |
B65D 81/3862
20130101 |
Class at
Publication: |
229/103.11 ;
220/592.2; 220/592.25; 220/592.26 |
International
Class: |
B65D 005/32; B65D
081/38; B65D 083/72 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 26, 2003 |
SG |
200307419-2 |
Claims
The claims defining the invention are as follows:
1. An insulation panel for use in thermally insulated shipping
containers, the panel comprising a rigid core of an insulation
material, the core being wholly encompassed within a polyethylene
foam envelope.
2. The insulation panel of claim 1 wherein the core comprises a
foam block of one of polyurethane and polystyrene or polyethylene
terephalate.
3. The insulation panel of claim 1 wherein the core is a closed
cell polyethylene foam.
4. The insulation panel of claim 1 wherein the core is a
non-cross-linked polyethylene foam.
5. The insulation panel claim 1 wherein the panel has an inner
surface, an outer surface and edge surfaces, the inner and outer
surfaces comprising a layer of polyethylene foam, the density of
the polyethylene foam forming the inner surface being greater than
the density of the polyethylene foam forming the outer surface.
Preferably the thickness of the polyethylene foam forming the inner
surface is less than the thickness of the polyethylene foam forming
the outer surface.
6. A thermally insulated container which includes at least one
insulation panel of claim 1.
7. The insulated container of claim 6 which includes a plurality of
the above insulation panels assembled into a square or rectangular
box with interconnecting sides and a closed bottom.
8. An insulated shipping container which includes at least one
thermally insulated container of claim 6.
9. The insulated shipping container of claim 8 which also includes
a reinforced cardboard carton.
10. A process for the manufacture of a thermally insulated
container comprising the steps of: (i) providing a first, second,
third and fourth rectangular polyethylene foam sections, each
section having two opposed ends; (ii) joining the sections together
at or near the ends of the sections so to provide a substantially
square or rectangular frame; (iii) providing a fifth polyethylene
foam section and joining the frame and the fifth section together
so to provide a container having a closed bottom and a cavity
therein; (iv) providing insulation material and locating the
material within the cavity so to fill or substantially fill the
cavity; (v) providing a sixth polyethylene foam section and joining
the container and the sixth section together to close the container
and provide the thermally insulated container.
11. The process of claim 10 wherein the sections are joined
together with airtight joints.
12. The process of claim 11 wherein the sections are joined
together by heat welding.
13. A process for the manufacture of a thermally insulated
container wherein a plurality of insulation panels of claim 1 are
joined together to provide an insulated shipping container.
14. The process of claim 13 wherein the panels are joined together
with airtight joints.
15. The process of claim 14 wherein the panels are joined together
by heat welding.
16. A process for the manufacture of a thermally insulated
container, the process comprising the steps of: (i) providing a
first, second, third, fourth, fifth, and sixth rectangular
polyethylene foam sections, each section having two opposed ends,
each panel comprising a rigid core of an insulation material, the
core being wholly encompassed within a polyethylene foam envelope;
(ii) joining the first, second, third, and fourth sections together
at or near the ends of the sections so to provide a substantially
square or rectangular frame; (iii) joining the frame and the fifth
section together so to provide a container having a closed bottom
and a cavity therein; (iv) providing the sixth polyethylene foam
section to close the container thus providing the thermally
insulated containers.
17. The process of claim 10 further comprising the step of joining
together with airtight joints.
18. The process of claim 16 further comprising the step of joining
the sections together by heat welding.
Description
FIELD OF THE INVENTION
[0001] The invention relates to insulated panels for use in
shipping containers. The invention also relates to a shipping
container intended for use in shipping and storing
temperature-sensitive products, such as frozen tissues and other
perishable products at critical temperature or range of
temperatures.
BACKGROUND OF THE INVENTION
[0002] A wide range of containers has been used or proposed for use
in storing and transporting temperature sensitive products.
Containers can include a cardboard shipping carton lined with
insulating material such as expanded polystyrene (EPS),
polyurethane or other foam material. The insulating material may be
provided in modular panels placed together to provide a central
insulated cavity. A plug or lid incorporating insulated material is
generally used to seal the cavity before the carton is closed and
prepared for shipping.
[0003] Alternatively, the insulated material can be provided by
injection moulding techniques so as to provide an integral body
having a central cavity. The body when fitted with a lid may itself
be used as a storage container or may be used within a cardboard
shipping carton or other protective material. The insulation
material can also be injected into an insulation space between an
outer container wall and a rigid inner liner.
[0004] When transporting particularly sensitive products, such as
certain medical or pharmaceutical products, rigid polyurethane
containers are often used. Polyurethane has thermal insulation
properties that are generally superior to EPS.
[0005] There are benefits and disadvantages with the two general
types of containers, particularly when they are used for the
shipping of large quantities of goods. Injection moulded containers
can be costly to manufacture due to the tooling costs and the need
to use blowing agents with EPS. The use of polyurethane instead of
EPS can reduce the tooling costs. However, polyurethane tends to
adhere to the wall surfaces creating disposing problems as both the
outer container, polyurethane and inner liner must be disposed
together. There are also significant storage and transportation
costs in respect of empty containers formed from EPS or
polyurethane.
[0006] Modular panels avoid some of these problems. Manufacturing
costs are reduced due to the use of less complicated and smaller
moulds. Transportation and storage costs of the panels tend to be
reduced as the panels can be stored in a more compact stacked
arrangement with separate flat packed cardboard shipping cartons
for assembly into a container as required. Modular panels can more
readily be reused as a damaged section will only require the
replacement of the panel incorporating the damage and not the whole
container. However, the effectiveness of the insulation in a
modular shipping container can be less than that of an equivalent
integral container due to the additional seams through which air
may enter and thereby warm the contents of the container. Whilst
the insulation properties can be improved by increasing the width
of the panels, this will reduce the internal storage capacity in
the shipping carton for the same size shipping carton and increase
transportation costs.
[0007] Another type of panel is the vacuum insulating panel (VIP).
These panels have a vacuum core formed of an open cell polymer foam
wholly encompassed by a suitable envelope such as mylar film or
aluminium foil. The panels are reported to have high R-values
(thermal resistances) in the order of R-30 per inch of thickness.
However, whilst VIP provides great thermal insulation, the panels
can be easily damaged. The R-value is significantly reduced as soon
when the envelope is punctured. This limits the use and reuse of
VIPs.
[0008] In addition to poor direct damage resistance, the R-values
of the panels also decrease due to the "Edge Effect" and "Ageing
Panel Effect" as described in An Introduction to VIP Technology, T.
K. Stovall, Vacuum Insulation Panel Symposium, Baltimore, May 3-4,
1999, Page 6, line 26-31. As a consequence VIPs are not considered
suitable for long life use.
[0009] Various types of insulated containers have been proposed and
described in the patent literature.
[0010] U.S. Pat. No. 5,441,170 describes a modular shipping
container with multiple inner compartments. Sandwiched insulation
panels are fitted within a conventional corrugated shipping
container. The panels are made from a polyisocyanurate core
sandwiched between reflective layers comprised of an aluminised
coating bonded to the core. The panels are encapsulated within a
thermoplastic envelope to allow the panels to be cleaned for
reuse.
[0011] U.S. Pat. No. 6,325,281 describes an insulated shipping
container having multiple layers of insulation. The container
comprises an outer cardboard carton, a rigid EPS housing, a
removable inner housing formed from VIPs and an inner closeable
carton within the inner housing. The patent attempts to overcome
the durability problem with using VIPs. The panels have a vacuum
core formed of an open cell polymer foam wholly encompassed by a
suitable envelope such as mylar film or aluminium foil.
[0012] U.S. Pat. No. 5,924,302 describes an insulated shipping
container having an integral body defining the cavity therein. The
lid includes protrusions to provide an enhanced seal with the
body.
[0013] U.S. Pat. No. 6,381,981 describes a shipping container
intended for use with frozen tissue samples. The container has an
outer housing formed of an insulated foam material such as EPS and
an inner container formed from VIP. The inner cavity incorporates a
spring assembly, which adjusts the size of the cavity to fit
smaller loads of transported product.
[0014] WO98/01359 describes a packaging container incorporating a
laminate consisting of a fibre core layer, an outer plastic film of
polypropylene, high density polyethylene or polyester and an inner
layer of aluminium foil coated with a polyethylene film.
[0015] U.S. Pat. Nos. 4,928,847; 5,102,004 and 5,111,957 all relate
to storage containers formed from a core of polyurethane and four
layers on the upper and lower surfaces, the four layers being
reinforced by polypropylene webbing and laminated with a
polyethylene film.
[0016] None of the above containers are entirely satisfactory so
that there is a need to provide a shipping container for shipping
and storing varying products at low temperatures for extended
periods of time, while minimising manufacturing, use, storage and
transportation costs of the container and its components. This is a
clear benefit in reducing the cost of using insulated shipping
containers by providing containers having a longer effective
lifespan (re-useable) and improved thermal efficiency so that less
insulation material is required improving payload capacity for a
standard size of shipping carton.
SUMMARY OF INVENTION
[0017] In an embodiment of the invention there is provided an
insulation panel for use in thermally insulated shipping
containers, the panel comprising a rigid core of an insulation
material, the core being wholly encompassed within a polyethylene
foam envelope.
[0018] Preferably the core comprises a polyurethane, polystyrene or
polyethylene terephalate foam block.
[0019] Preferably the polyethylene foam is a closed cell foam.
[0020] Preferably the polyethylene foam is a non-cross-linked
foam.
[0021] Preferably the panel has an inner surface, an outer surface
and edge surfaces, the inner and outer surfaces comprising a layer
of polyethylene foam, the density of the polyethylene foam forming
the inner surface being greater than the density of the
polyethylene foam forming the outer surface. Preferably the
thickness of the polyethylene foam forming the inner surface is
less than the thickness of the polyethylene foam forming the outer
surface.
[0022] Preferably the panel is adapted so that permit the panel to
engage with at least one other panel. Preferably the panels are
adapted to engage by tongue and groove, mitred or dove tail
join.
[0023] In another embodiment of the invention there is provided a
thermally insulated container that incorporates one or more of the
above insulation panel(s).
[0024] Preferably the thermally insulated container includes a
plurality of the above insulation panels assembled into a square or
rectangular box with interconnecting sides and a closed bottom.
[0025] In another embodiment of the invention there is provided a
shipping container having a plurality of interconnecting sides and
a closed bottom and a sealable top, the shipping container
including at least one thermally insulated container as described
above.
[0026] In another embodiment of the invention there is provided a
process for the manufacture of an insulation panel for use in
thermally insulated shipping containers comprising the steps
of:
[0027] (i) providing a first, second, third and fourth rectangular
polyethylene foam sections, each section having two opposed
ends;
[0028] (ii) joining the sections together at or near the ends of
the sections so to provide a substantially rectangular frame;
[0029] (iii) providing a fifth polyethylene foam section and
joining the frame and the fifth section together so to provide a
container having a closed bottom and a cavity therein;
[0030] (iv) providing insulation material and locating the material
within the cavity so to fill or substantially fill the cavity;
[0031] (v) providing a sixth polyethylene foam section and joining
the container and the sixth section together to close the container
and provide the insulation panel.
[0032] Preferably the joins between all sections are airtight or
substantially airtight. Preferably the sections are joined by heat
welding.
BRIEF DESCRIPTION OF THE DRAWING
[0033] The above invention will now be described with reference to
the following detailed description of a preferred embodiment of the
invention as illustrated in the accompanying drawings, in
which:
[0034] FIG. 1 is a perspective view of a sandwich insulation panel
of the invention.
[0035] FIG. 2 is an enlarged, fragmentary cross-section view of the
sandwich panel shown in FIG. 1.
[0036] FIG. 3 is a side cross-sectional view of the sandwich
insulation panel of FIG. 1 taken through A-A.
[0037] FIG. 4 is a top cross-sectional view of the sandwich
insulation panel of FIG. 1 taken through B-B.
[0038] FIG. 5 is a perspective view of an insulated container
formed from sandwich panels of the invention.
[0039] FIG. 6 is an exploded perspective view of an insulated
shipping container of the invention. The container includes the
insulated container of FIG. 5 together with a shipping carton,
inserts, refrigerants, payload box and a sandwich panel lid.
[0040] FIG. 7 is a view of a vertical cross-section of an insulated
shipping container of the invention. The payload box and
refrigerants have been omitted.
[0041] FIG. 8 is a fragmentary side view of an insulated shipping
container of the invention. The broken parts show the insulated
container formed from sandwich panels within the shipping
carton.
[0042] FIG. 9 is a perspective view of an alternative shipping
container of the invention. The shipping carton contains four
insulated containers formed from sandwich panels.
[0043] FIG. 10 is plan view of the use of apparatus in a step in
the manufacture of a sandwich panel of the invention.
[0044] FIG. 11 is a front view of the apparatus of FIG. 10 taken
through C-C.
[0045] FIG. 12 is a side view of the apparatus of FIG. 10 in
direction of D.
[0046] FIG. 13 is a plan view of apparatus of FIG. 10 when used in
another step in the manufacture of a sandwich panel of the
invention.
[0047] FIG. 14 is a side view of another apparatus when used in a
step in the manufacture of a sandwich panel of the invention.
[0048] FIG. 15 is a perspective view of the intermediate product of
using the apparatus of FIGS. 10 to 14.
[0049] FIG. 16 is a side view of the apparatus of FIG. 14 when used
in a further step in the manufacture of a sandwich panel of the
invention.
[0050] FIG. 17 is a perspective view of alternative panels of the
invention.
[0051] FIG. 18 is a perspective view depicting stages in the
assemble of the panels of FIG. 17 into an insulated container.
[0052] FIG. 19 a perspective view of alternative panels of the
invention.
[0053] FIG. 20 is a perspective view depicting stages in the
assemble of the panels of FIG. 19 into an insulated container.
[0054] FIG. 21 is a temperature vs. time graph for insulation box
formed from 1 inch (25 mm) polyurethane panels (without
lamination--panels not of the invention).
[0055] FIG. 22 is a temperature vs. time graph for insulation box
formed from 38 mm (1 inch+13 mm) polyurethane panels (without
lamination--panels not of invention).
[0056] FIG. 23 is a temperature vs. time graph for insulation box
formed from polyurethane (1 inch) and polyethylene panels (13 mm)
(without lamination--panel not invention).
[0057] FIG. 24 is a temperature vs. time graph for an insulation
container of the invention formed from sandwich insulation panels
of the invention (10 mm polyethylene, 1 inch (25 mm) polyurethane,
3 mm polyethylene)
[0058] FIG. 25 is a temperature vs. time graph for insulation box
formed from 2 inch (50 mm) polyurethane panels (without
lamination--panels not of the invention).
[0059] FIG. 26 is a temperature vs. time graph for an insulation
box formed from 73 mm (2 inch+13 mm) polyurethane panels (without
lamination--panels not of invention).
[0060] FIG. 27 is a temperature vs. time graph for an insulation
box formed from polyurethane (2 inch) and polyethylene panels (13
mm) (without lamination--panel not of invention).
[0061] FIG. 28 is a temperature vs. time graph for an insulation
container of the invention formed from sandwich insulation panels
of the invention (10 mm polyethylene, 2 inch (50 mm) polyurethane,
3 mm polyethylene)
DETAILED DESCRIPTION OF THE INVENTION
[0062] The invention is predicated on the finding that the
insulation panels of the invention can, when fitted together to
form a thermally insulated container, provide a container having
enhanced thermal insulation properties over that expected from a
similarly sized mass of foam insulation, such as rigid polyurethane
or EPS insulation material. The improvement appears to be as a
result of wholly encompassing the core insulation material within a
polyethylene foam envelope. It is speculated that the envelope
improves the insulation characteristics of core insulation material
by providing an improved seal at the seams between interconnected
panels. The envelope may also improve the insulation properties of
the insulation material by providing an airtight covering over the
core insulation material.
[0063] An insulation panel is depicted in FIGS. 1 to 4. Each panel
comprises a core of insulation material and polyethylene foam. The
depicted insulation panel (1) is rectangular although it could be
provided in a broad range of shapes depending on the shape of the
shipping container in which the panel is intended to be used. The
panel (1) comprises an outer polyethylene foam member (3), an inner
polyethylene foam member (5), four perimeter polyethylene foam
strip or side members (7, 9, 11, 13) located around a foam core
(15). The outer member (3) of the panel forms part of the outer
surface of an insulated container and the inner member (5) defines
part of the inner cavity defining wall of the insulated container
when the panel is incorporated into an insulation container.
[0064] The foam core can be selected from a broad range of polymer
insulation foams examples of which include polyolefins (such as
polyethylene and polypropylene), polystyrenes, polyurethanes
(including polyisocyanurate), PET (Polyethylene terephalate) and
polyvinyl chloride, with EPS and rigid polyurethane being
particularly preferred. The core should also provide some rigidity
to the panel and this can be achieved by using rigid polyurethane.
A plate such a lightweight aluminum sheet may also be included in
the core to enhance the rigidity of the core and the panel
containing the core. The properties of polyurethane and EPS make
both types of polymers particularly suitable for use in the panel
as foam core (15). The foam core may be a single block or may
comprise a number of blocks which together provide the foam core.
The blocks can be provided in a suitable shape by any means, such
as by using moulds or by cutting. or shaping extruded materials.
The foam core can also be provided by injecting suitable polymer
material such as polyurethane into the cavity within the
polyethylene envelope. The use of polyurethane has the advantage of
filling the cavity and bonding the foam core to the polyethylene
envelope.
[0065] A closed cell polyethylene foam should be used for the
polyethylene foam envelope. Whilst cross linked polyethylene foam
can be used, it is preferred to use non-cross linked polyethylene
foam as it is both cheaper and easier to work with when forming the
envelope. A large range of polyethylene foams are commercially
available, and are thought to be useable. The preferred
polyethylene foams are those provided by Fagerdala World Foams.
[0066] It is preferred for the outer polyethylene foam member (3)
to be at least 5 mm thick, more preferably of from 5 mm to 20 mm
and most preferably approximately 10 mm. The width of the outer
foam member enhances the insulation properties of the core, by both
providing additional insulation and by providing the core
insulation material with additional protection from damage, such as
that which can occur during the transporting of shipping cartons. A
10 mm layer of polyethylene foam helps to cushion the core from
damage and thereby the insulation reducing affect that the damage
may have had on the core. The density of the polymer is preferably
equal to or greater than 15 kg/m.sup.3, preferably of from 20 to 40
kg/m.sup.3 and most preferably approximately 30 kg/m.sup.3. When
necessary, further protection against damage can be provided by
including a thin layer of a light weight resilient material such as
an aluminium sheet between the outer foam member and the core.
[0067] The inner member (5) may be of from 0.5 mm in thickness, and
more preferably of from 1 mm to 5 mm and most preferably
approximately 2 or 3 mm. The thickness of the inner member (5) is
preferably significantly less than that of the outer member (3) as
it should not be necessary to cushion and protect the panel core
from blows coming from within the insulation container once
assembled. However, it is preferred to use a polymer layer that
facilitates the reuse of the panels. For hygiene and ease of
cleaning the inner member is preferably made from a polymer foam
with a higher density than that of the polyethylene polymer used in
the outer layer. The foam should have fine cell structures so that
it is suitable for use with medical products with their more
stringent hygienic requirements. It is preferred that the inner
member has a density of from 60 kg/m.sup.3, preferably of from 80
kg to 250 kg/m.sup.3, and most preferably approximately 100
kg/m.sup.3.
[0068] For additional insulation the inner foam member may also
include an aluminum foil layer. The inclusion of a thin reflective
layer such as aluminum may further increase the insulation
properties of the panel. The foil may be protected with a thin film
layer of polyethylene.
[0069] The perimeter polyethylene foam strip members (7, 9, 11 and
13) are preferably located in the gap between the outer and inner
polyethylene foam members so as to provide a flush edge surface. An
alternative arrangement of locating the strip members against the
edge of the outer and inner members will also provide a flush edge
surface but is less preferred. The edge portion of a panel is
likely to be subject to stresses and damage during its placement
and it is thought that the alternative arrangement would not
provide a panel as resilient as the panel depicted. Another
alternative is the use of corresponding mitre edges on both the
strip members and the outer and inner members, although this
arrangement is not preferred as it is thought to unnecessarily
complicate the manufacture of the panels.
[0070] The strip members (7, 9, 11 and 13) are preferably made of
polymer foam having the same thickness and density as the outer
foam member as earlier described.
[0071] Fagerdala Fawolam polyethylene foams are suitable for use
for the outer, inner and strip members. Fawolam 30 provides a
closed cell, non-cross linked polyethylene foam having an average
density of approximately 30 kg/m.sup.3. Fawolam 100 provides a
closed cell, non-cross linked polyethylene foam with an average
density of approximately 100 kg/m.sup.3.
[0072] The inner, outer and strip members are preferably bonded in
a manner so as to create strong and preferably airtight joins
between the adjoining members in each panel. This can be achieved
by a range of known methods. Two preferred arrangements include
heat welding and the use of adhesive. Additional bonding can be
provided by the use of an adhesive with the core member, or by
forming the core foam by injecting a polyurethane foam mixture into
the cavity. However, it is generally sufficient to simply locate
and encapsulate the core material within a polyethylene
envelope.
[0073] The foam core (15) provides most of the insulation
properties of the panel. Rigid polyurethane is preferred and
provides good insulation properties with R-values in the order of
R-8 to 9 per inch of thickness. EPS has lesser insulation
properties with R-values in the order of R-4 to R-5. The difference
is a result of the cell structure in polyurethane foams which is
denser than in most other materials and the cells are filled with
an inert gas that has a higher R-value. Over time the inert gas
leaks from the cells in polyurethane and is replaced with air,
resulting in a reduction in the R-value of the foam, to something
in the order of R-7 per inch after 2 years. The R value of
polyurethane will then stabilize around R-7, but can further
decrease if the foam is damaged or cracked. The required thickness
of the core thus depends on the insulation material used in the
core and the time period and required temperature. The insulation
panels when assembled into an insulation container should be
capable of maintaining the temperature within the container within
a desired temperature range for a required time period whilst the
goods are stored and transported. Typical thicknesses of
polyurethane cores are in the order of from 15 mm to 100 mm, more
preferably 20 mm to 80 mm, most preferably approximately 24 or 51
mm (1 or 2 inches). The thickness of the core must be increased
when EPS is used to provide the same insulation properties.
[0074] The ability of an insulation panel to slow down the transfer
of heat into the container is dependent on the R-value of the
panel. With the same thickness of panel, the materials with a
better R-value will provide better insulation. The combined core
and envelope foam concept has resulted in an increase in the
R-value of the panel and therefore better thermal performance.
[0075] FIG. 5 depicts an arrangement of five insulation panels (35,
36, 38, 40 and 42) assembled together so to form an insulation
container. A horizontal rectangular panel (35) provides the
container bottom with four walls being provided by four vertical
panels (36, 38, 40 and 42). As depicted the vertical panels are
located on top of the base panel with the outer surface of the
vertical panels being aligned with the perimeter of the base panel.
Other arrangements providing the same general shape of insulation
container are possible. For example the vertical panels can be
arranged to form a tube and the base panel fitted therein so that
downward horizontal face of the vertical panels in combination with
the base panel forms the bottom of the container.
[0076] The vertical panels are arranged so that panels (36) and
(40) and panels (38) and (42) are directly opposite and parallel to
each other, with panels (38) and (42) being located between panels
(36) and (40), with the vertical sides of the panels (38) and (42)
abutting against the inner polyethylene layer of panels (36) and
(40). Alternatively, the pairs of panels can be parallel but offset
from one so that an outer vertical edge of each panel defines a
corner of the container. The other outer vertical edge (and the
adjacent vertical side face) of each panel abuts against the inner
vertical surface of the adjacent panel.
[0077] The panels may be fixed together and fitted with a lid so as
to provide a stand alone container or may be arranged within a
shipping carton or other container. When forming a stand alone
container the panels may be joined together by commonly used
fastening means. Adhesive, sealant and/or fasteners may used to
hold and seal touching panels together. Adhesives that do not
damage the contacting polyethylene foam layers are preferred. A
board range of fasteners can be used such as screws, nails and nuts
and bolts. The shaft of bolts can be fitted into aperture in one
panel and threaded into a nut located within a bore in an adjacent
panel. The panels themselves may be shaped so that they engage
adjacent panels and tightly fit together. The side edges of the
panels may be configured so to provide tongue-in-groove or dove
tailed joins. Such an arrangement is depicted in FIGS. 17 and 18
and is discussed further below.
[0078] The lid may be another insulation panel of the invention or
may be formed from other insulation materials. It can be useful to
use a breathable lid so to allow for the release of gas pressure
within the container when it is used with dry ice as a coolant. As
dry ice evaporates to its gas form it creates a large volume of
carbon dioxide gas which needs to be vented to avoid dangerous
pressure build ups within the container. The United Parcel Service
of America requires insulation boxes used with dry ice to be
appropriately vented so to avoid the pressure build up.
[0079] The insulation container shown in FIG. 5 is preferably
assembled within a cardboard shipping carton. Shipping cartons are
provided in standardized shapes for ease of storage and transport.
The carton provides additional protection for the panels and the
goods being stored and transported. The internal walls of the
carton can be used to position and restrain the movement of panels
of an appropriate size and shape thereby avoiding the need to affix
the panels together. Such an arrangement is shown in FIGS. 6 to
8.
[0080] The insulated shipping carton includes a conventional
reinforced shipping carton comprising a horizontal bottom wall
(19), four vertical side walls (20, 22, 24 and 26) and an opening
sealable by the four top flaps (28, 30, 32 and 34) hingedly joined
to the side walls. The opening can be sealed by folding inward the
four top flaps so to provide a substantially horizontal surface and
sealed using conventional fastening means such as tape or
staples.
[0081] An insulation panel (35) is laid horizontally at the bottom
of the carton to form the bottom of the insulation container. The
outer polyethylene member of the panel faces downward and contacts
the inner surface of the bottom wall (19) of the carton. The length
and breadth of the panel (35) are such that each of the four
horizontal side faces abut against or are closely adjacent to the
inner surface of carton walls (20, 22, 24 and 26). Four insulation
panels (36, 38, 40 and 42) are placed vertically on top of the
bottom panel to provide the insulation container as depicted in
FIG. 5. The outer polyethylene members of the panels (36, 38, 40
and 42) respectively abut against the inner surface of carton walls
(20, 22, 24 and 26). The outer polyethylene member of panel (36) is
in facial contact with the inner surface of carton wall (20). One
vertical side face of the panel abuts against a portion of the
inner surface of carton wall (22) at and near the junction of walls
(20) and (22). The opposite vertical side face of panel (36) abuts
the inner carton wall (26) at and near the junction of walls (20)
and (26). Likewise the panel (40) is in facial contact with the
inner carton wall (24) and the side faces contact inner carton
walls (22) and (26). The panels (38) and (42) fit between and abut
against panels (36) and (40) with the outer polyethylene member in
facial contact with the inner carton walls (22) and (26).
[0082] The insulated shipping container includes bottom and top
inserts (44) and (46) of open cell polyurethane. The horizontal
inserts are positioned within the insulation container and the side
faces thereof abut against or are closely adjacent to the inner
surface of the vertical panels and thereby act to hold panels (38)
and (42) into position by preventing the inward movement of these
panels. The inserts can be formed from a range of materials
although it is preferred to use polyurethane foam. The bottom
insert is preferably formed from an absorbent open cell material
such as the polyurethane foam so that the absorbent material absorb
liquid spills and protects against damage caused by leakage. The
top insert also braces the panels (38) and (42) and thereby
prevents the inward movement of the panels. The bracing action of
inserts (44) and (46) can be seen in FIG. 7.
[0083] The top insert can also be used to hold the payload (50) and
the refrigerants (52) in a fixed position and thereby reduce the
likelihood of damage to the payload due to vertical movement within
the overall insulated shipping container. The top insert (46) is
preferably made from open cell polyurethane as it will allow gas to
escape through the open cell structure and thereby permit the use
of the dry ice in the USA as a coolant. The use of polyurethane
foam inserts (44) and (46) also has the advantage of placing
additional insulation about the payload.
[0084] The insulated container is then closed by placing a top
insulated panel (48) on top of the vertical panels (36, 38, 40 and
42). The outer polyethylene member of panel (48) should be
positioned upwards. The inner member faces downwards and a portion
of the inner member at and near the perimeter of the panel abuts
against the top side faces of panels (36, 38, 40 and 42). This is
the preferred arrangement as the six panels (35, 36, 38, 40, 42 and
48) together provide a rigid protective barrier around the payload.
If a second carton was stacked on top of the first, the weight of
the second carton would need to break the top bridging panel (48)
before the weight of the second container would compress and
possibly damage the payload.
[0085] In an alternative arrangement the vertical panels extend the
height of the carton and a top panel is used as a horizontal plug
within the vertical panels. However, this alternative arrangement
is not preferred as the payload may be at a greater risk of damage.
If a smaller carton were to be stacked on top of an insulated
shipping carton of the alternate arrangement then the smaller
carton could be stacked directly above the plug panel. Whilst a
significant portion of the forces involved may be borne by the
sealed top flaps (28, 30, 32 and 34) the weight of the smaller
carton would press down on the plug panel which could move downward
and damage the payload.
[0086] Whilst not shown in the figures, a plastic liner, such as a
polyethylene film can also be used to protect against spills and
damage. Individual panels can be provided within a plastic liner so
as to facilitate the cleaning and re-use of the panels. The payload
within the insulation container and the insulation container per se
can each be located within a protective plastic liner.
[0087] Whilst a single insulation box has been shown, it is well
within the scope of this invention to vary the number of the
sandwich panels, the corresponding sizes thereof or even the number
of compartments so as to provide a wide range of insulated shipping
cartons. FIG. 9 depicts a four compartment insulation shipping
carton of the invention. Insulation panels (58) have been assembled
within a shipping carton (56) to provide the four insulated
compartments each with a plug lid (60). One compartment is shown
open with the plug lid (60) placed on top of the adjacent
compartments. The plug lid can comprise an insulation panel of the
invention or may comprise a polyurethane insert such as that used
as the top insert in FIG. 6.
[0088] The insulated shipping container can be used for the
transport of various temperature sensitive payloads. The payload
(50) may be packaged within a separate box or bag and located with
the insulated container. The temperature sensitive nature of the
payload will affect the selection of an appropriate refrigerant
(52) for use within the container. For example a temperature range
of from 2 to 8.degree. C. may be required for shipment and
transportation of vaccines, pro-biotics, muscle relaxant drugs,
dental bonding adhesives and human organ preservations. A
temperature range of 0 to -19.degree. C. can be required for
shipment of biologics, diagnostic kits (such as HIV, HBV and HVC
kits), reagent test kits and "surgical glues" for wound closures. A
temperature range of -20 to -68.degree. C. can be required for the
storage of blood plasma concentrate, tissue grafts and activated
myoblasts. A range of commonly available refrigerants, such as
cubes of ice and dry ice, can be used to meet the required
temperature ranges.
[0089] The method and apparatus for use in forming the insulation
panels of the invention is shown in FIGS. 10 to 16. Three 10 mm
thick polyethylene strip members of Fawolam-FS-30 (7, 9, 11) are
positioned on the apparatus and secured in position by the back
stopper (70), side stopper (72) and the pneumatically operated back
(74) and side clamps (76). Hot air is piped through pipe (78) into
a hot air discharge blade (80) which discharges the hot air through
a vertical line of apertures (82) located on both sides of the
blade. The hot air heats the end faces of strips (9) and (11) and
end portions of the rear face of strip (7) at an appropriate
temperature for specific time period. Once heated for the required
time, the hot air discharge blades withdraw to the sides of the
apparatus. The strip members (9) and (11) are then moved into
contact with strip (7) so that the heated parts of the strips bond
together.
[0090] Once the strips (7, 9 and 11) have been heat sealed together
the partially completed frame is then flipped 180.degree. manually
to the opposite side as shown in FIG. 13. Once the partial frame is
secured in the flipped position, another strip member (13) is
clamped into position placed against the back (70) and side stopper
(72).
[0091] The free end faces of strips (9) and (11) and end portions
of the inner face of strip (13) are heated by a repositioned hot
air discharge blade (80) and strip (13) is then heat sealed to the
partially completed frame to provide the completed frame.
[0092] The frame is then sealed to a 10 mm thick outer foam member
(3) of Fawolam-FS-30 foam as shown in FIG. 14. A hot air discharge
pipe (84) is used to heat an edge surface of the frame (83) and the
outer foam member is gently rolled between the hot air discharge
pipe (84) and the fine-tune roller (86) to seal the foam member to
the frame which is moved by the frame roller (88).
[0093] A foam core (15) of rigid polyurethane is then inserted into
the central cavity formed by the sealed combination of the outer
and strip members (3, 7, 9, 11 and 13) as shown in FIG. 15.
[0094] As shown in FIG. 16, the panel is then completed by bonding
an inner foam member (5) of a thinner, higher density polyethylene
foam (Fawolam-FS-100; 3 mm thick) over the open face of the foam
core (15) and the surrounding frame of strip members (7, 9, 11 and
13). The apparatus used is that of FIG. 14 and it is operated in
the same manner.
[0095] The apparatus shown in FIGS. 10 to 14 can be modified for
use in heat sealing insulation panels together so to provide rigid
insulation container which can be used alone or within shipping
cartons. The strips members (7, 9, 11 and 13) and outer member (3)
are respectively replaced with the vertical panels (36, 38, 40 and
42) and horizontal panel (35) and enlarged hot air discharge blades
are used. An insulation container formed by heat sealing the panels
together should have improved insulation properties due to the
effective removal of seams.
[0096] FIGS. 17 to 20 relate to shaped panels of the invention.
Each sandwich panel has been adapted to engage the adjacent
(non-lid) panels so that they inter-fit and/or inter-lock together.
The panels are formed from shaped form cores of polyurethane
encompassed within a polyethylene foam envelope. The method of
forming the panels is substantially the same as that described
above with reference to FIGS. 10 to 16.
[0097] In FIG. 17 the side wall four panels (90, 92, 94, 96) are
adapted for a male/female engagement with adjacent side panels.
Each side panel has a tongue (98) extending from a vertical side
edge and a vertically extending groove (100) on the internal side
face proximal to the opposed vertical side edge of the panel. The
tongue and groove of adjacent side panels are shaped so as to allow
the tongue of one panel to fit within the groove of the adjacent
panel. Preferably the tongues and grooves closely correspond so
that a tight fit is provided between fitted together side panels.
The dimensions of the tongue and groove do not need to be precise
and there is some tolerance due to the compressibility of the
polyethylene foam layer around the tongue and groove.
[0098] As shown in FIG. 17 the tongue and groove engagement between
side panels are incline so prevent the panels for being pulled
apart in use. The angle of the tongues and grooves prevents the
sideways separation of side panels but allows the panels to be
separated by moving one panel relative to the other along of the
length of groove. This is a preferred arrangement and it is
expected that the incline can be omitted with some applications of
the insulated container. This can be done by restraining the
movement of the walls of the container by another means such as
straps or other fasteners, or the internal walls of a shipping
carton.
[0099] The panels are side panels (90, 92, 94 and 96) are adapted
to engage the bottom panel (101) by having tongues that extend from
their bottom edges capable of fitting within grooves (102, 104,
106, 108) located in the inner face of the bottom panel near the
perimeter of the inner face. The two of the grooves (102, 104) are
inclined so to restrain the vertical movement of two of the side
panels (90, 92) which have tongues with corresponding angles. As
above, the incline can be omitted with some uses of the insulated
container. The tongue of the other two panels (94, 96) and the
equivalent grooves (106 and 108) have vertical or near vertical
sides so to permit the downward extending tongues to be inserted
into the bottom panels as the panels (94, 96) are fitted into
panels (90, 92).
[0100] An alternative fitting arrangement-is shown in FIG. 19. Two
of the side panels (110, 114) have two substantially vertically
extending grooves (120, 122) in the inner face, a groove located
near oppose side edges of the panel. Two of the side panels (112,
116) each have two side tongues (124, 126) extending from the side
edges of the panels. The tongues of the panels (112, 116) are
adapted to fit within and engage with the grooves of panels (110,
114). In essence, two of the side panels (112, 116) are male/male
and are adapted to fit and engage the grooves of the female/female
side panels (110, 114). The side panels have downward extending
tongues (128) which fit into grooves (130) located in the bottom
panel (117).
[0101] The steps involved in the assemble of the panels of FIGS. 17
and 19 into an insulation container are respectively shown in FIGS.
18 and 20. The assemble method is similar for both sets of
panels.
[0102] As shown at (A), the tongue of a side panel is being fitted
in the corresponding groove of the bottom panel and pushed so that
the bottom edge tongue slides along the groove, but is vertically
held within the groove. When this step has been completed the
assembly will look like (B). The tongue of an oppose side panel is
slide along the opposite groove (C) the groove, until it was
satisfactorily positioned. (D). A further side panel is positioned
(E) for location into the assembled position so that the tongues
and grooves of adjacent side panels interfit, and eventually the
bottom edge tongue of the fits within a corresponding groove in the
bottom panel (F). Another side panel is then positioned so that the
tongues and grooves of the adjacent side panels can interfit (G)
and slide down into position (H).
[0103] FIGS. 21 to 28 depict the results of testing the insulation
properties of assorted insulated containers formed from comparative
panels (FIGS. 21 to 23, 25 to 27) and from panels of the invention
(FIGS. 24 and 28).
[0104] The tests were conducted using a datalogger XR 440M Pocket
Logger (Pace Scientific Inc).
[0105] The polyurethane foam had a density of 85 kg/m.sup.3.
[0106] The polyethylene foams were Fawolam 30 kg/m.sup.3 on the
outer side of the panels and Fawolam 100 kg/m.sup.3 on the inner
side of the panels.
[0107] The test panels were assembled into insulation boxes and
fitted with temperature sensors. Each box was loaded with 5 kg of
gel ices (Techni Ice) and the internal temperature within the box
was monitored over time.
[0108] The results of the tests show that providing a polyethylene
foam envelope around the polyurethane core material significantly
improves thermal insulation by as much as 21 hours, compared to
100% polyurethane without any polyethylene material. This can be
seen from a comparison of FIGS. 21 and 24, and 25 and 28.
[0109] The results appear to go beyond a mere additive effect. A
significant improvement in the insulation properties of the
containers by using a polyethylene envelope was noted from the
temperature time profiles shown in FIG. 24 over 23 and FIG. 28 over
27.
[0110] The addition of a polyethylene foam layer alone without
enveloping the core was found to provide an increase in thermal
insulation over the core alone. This is apparent from a comparison
of FIGS. 21 and 23, and 25 and 27. Surprisingly, the addition of a
layer of Fagerdala Fawolam polyethylene to polyurethane foam core
seem to provide a significant improvement over a comparable total
thickness of polyurethane foam, (compare the temperature time
profiles of the graphs of FIGS. 22 with 23, and also FIGS. 26 with
27) and despite the lower R value for the polyethylene foam.
* * * * *