Information
-
Patent Grant
-
6234341
-
Patent Number
6,234,341
-
Date Filed
Thursday, March 16, 200025 years ago
-
Date Issued
Tuesday, May 22, 200124 years ago
-
Inventors
-
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 220 59203
- 220 59209
- 220 5921
- 220 5922
- 220 59225
- 220 59226
- 220 15
- 220 59201
- 220 588
- 220 586
- 220 611
- 220 612
- 220 613
- 220 678
- 220 6222
-
International Classifications
-
Abstract
A transport container comprises an insulating block. A plurality of layers of flexible insulating foam material form sides of the container and are mounted on the block which closes one end of the container. A pressure envelope applies pressure around the exterior of the sides and the block.
Description
TECHNICAL FIELD
This invention relates to a transport container for use in transporting temperature sensitive products and keeping them either cool or protecting them from chilling in transit, as required.
BACKGROUND ART
Certain products need to be kept cool whilst being transported from place to place by postal or courier services, particularly from a manufacturer or distributor to a consumer for the product concerned. Examples of such products are food products, pharmaceuticals and bio-chemicals including diagnostics, and they are generally known as “cold chain” products. Other products need to be protected from chilling during transport, particularly from freezing in air cargo, and in this specification these products are referred to as “warm” products. Examples of “warm” products include certain other foodstuffs and pharmaceuticals, and blood products.
“Cold chain” and “warm” products have until now generally been transported in thermally insulated rigid containers such as fabricated polystyrene foam boxes as an example, but such containers can be fragile, expensive and inefficient.
It is an object of the present invention to provide an improved transport container.
DISCLOSURE OF INVENTION
In accordance with the present invention, a transport container comprises an insulating block, a plurality of layers of flexible insulating foam material forming sides of the container and mounted on the block which closes one end of the container, and a pressure envelope for applying pressure around the exterior of the sides and the block.
Preferably the pressure envelope is a heat shrunk polyethylene envelope.
Preferred also the insulating block is formed from stiff polyethylene foam.
Preferred also the sides of a plurality of layers of said flexible insulating material at least one sheet of said flexible insulating material wound a plurality of times around itself to form said plurality of layers.
Preferred further said at least one sheet of said flexible insulating material is wound a plurality of times around itself and around at least a portion of the insulating block.
Preferred further at least a portion of the insulating block is attached to at least the outer edge of the outer layer of the plurality of layers of said flexible insulating material at said one end of the container.
Preferred further said at least one sheet of said flexible insulating material is wound a plurality of times around itself and around at least a portion of the insulating block, and another portion of the insulating block is attached to at least the outer edge of the outer layer of the plurality of layers of said flexible insulating material at said one end of the container.
Preferred further the insulating foam material is of closed-cell low-density polyethylene.
Preferred further at least one of said plurality of layers is attached to the block by heat-bonding, or by adhesive, or by the use of adhesive tape.
Preferred further a strip of adhesive tape lapping over both said outer edge and a portion of the insulating block all the way around the block attaches the sides of the container to the block.
Preferred further the container includes closure means for closing the other end of the container.
Preferred further said closure means comprises a further insulating block to be attached to the sides to close the other end of the container.
Preferred further the transport container contains dry ice and a product to be transported in the transport container.
Preferred further the closed cells in at least the inner layer of the plurality of layers of the sides of the container are pressurised and expanded in the plane of the inner layer by the carbon dioxide gas sublimed from the dry ice.
The present invention also in a transport which has been used for transporting a product and has contained dry ice, wherein any closure means has been opened, the block has been removed, the sides have been flattened and at least the inner layer of the plurality of layers of the sides of the container has been thinned.
Other preferred features of the invention will be apparent from the following description and from the subsidiary claims of the specification.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be further described, merely by way of example, by reference to the accompanying drawings, in which:
FIG. 1
is a perspective view of a transport container according to a preferred example of the invention, including its closure;
FIG. 2
is a cross-sectional view taken on the plane
2
—
2
on
FIG. 1
;
FIG. 3
is a cross-sectional view taken on the plane
3
—
3
on
FIG. 1
; and
FIG. 4
is a view similar to
FIG. 3
, but showing a modification of the preferred example.
BEST MODE OF INVENTION
Referring initially to
FIGS. 1-3
in the preferred example of the invention, a rigid circular disc
10
some 12 mm thick of polyethylene foam is glued coaxially on one side of another disc
11
of the same foam but of larger diameter to form a block
12
of T-shaped cross-section for a transport container
13
. The projection of the edge of the larger diameter disc
11
beyond the edge of the smaller diameter disc
10
constitutes a flange
14
. If required, the block
12
can be formed integrally in the same shape as that just described.
A single sheet
15
of flexible low-density polyethylene closed-cell insulating foam material as one edge
16
wound around the edge of the disc
10
and seating against the flange
14
. When the edge
16
of the sheet
15
has been wound all of the way around the edge of the disc
10
, it has returned to its starting point
17
, and winding then continues around the outside of the already-wound sheet and many more times to build up a multi-layered roll
18
of approximately circular cross-section of a plurality of layers of the sheet
15
of flexible insulating foam material. The roll
18
forms the sides of the transport container
13
.
FIGS. 2 and 3
show eight layers in the multi-layered roll
18
, but either more or less layers can be used.
The last layer is approximately flush with the edge of the disc
11
and is attached to it by a length of adhesive tape
19
extending around the edge of the disc
11
and also lapping over the outer edge of the roll
18
. The tape
19
is shown in
FIG. 2
only. Alternatively the edge
16
of the sheet
15
is attached by bonding to the edge of the disc
11
and the flange
14
, and the edges
16
of each of the layers of the roll
18
are bonded together and to the flange
14
. Bonding is achieved by adhesive or by heat sealing using a jet of hot air at a temperature of greater than 120 degrees Celsius. The block
12
closes one end of the container
13
. The other end
19
of the container
13
is open, and the adjacent edges
20
of the layers of the sheet may be bonded together if required.
The block
12
and the roll
18
attached to it are inserted in a heat-shrinkable polyethylene pressure envelope
26
with the block
12
in the closed-end of the envelope
26
and the wall of the envelope
26
extending along the roll
18
and tucked at
27
into the end
19
of the container. The envelope is omitted from
FIG. 1
, but shown in
FIGS. 2 and 3
. The polyethylene envelope
26
is initially a loose fit over the block
12
and the roll
18
as shown in
FIGS. 2 and 3
for clarity, and is subsequently heat-shrunk to apply pressure to grip tightly onto the roll
18
and underneath the block
12
, principally to reinforce the attachment of the block
12
to the roll
18
during the filling of the container
13
and during its subsequent handling and transport. The envelope
26
also reinforces the end
19
of the container
13
and the adjacent edges
20
of the layers of the sheet
15
. The part
27
of the envelope
26
inside the roll
18
does not shrink, but remains highly flexible.
It will be appreciated that all of the components of the transport container
13
described thus far, ie. the block
12
, the roll
18
and the envelope
26
, are made of polyethylene, which facilitates recycling and disposal of the container
13
after use, but if desired the pressure envelope
26
may be of a different material, for example an elastomeric material.
The container
13
is provided with a closure
28
, shown in
FIG. 1
only, which is of the same construction, shape and size as the block
12
. Thus the closure
28
comprises a large diameter disc
29
which fits as a cap on the end
19
of the roll
18
, and a coaxial small diameter disc
30
which fits snugly into the end
19
. The projection of the large disc
29
beyond the small disc
30
constitutes a flange which seats on the envelope
26
where it passes over the edges
20
of the layers of the sheet
15
.
In use the transport container
13
can be stood on end on the block
12
in a stable position to be filled, or can be filled lying on its side if this is convenient, the combination of the block
12
, the multi-layered roll
18
and the pressure envelope
26
giving the container
13
substantial rigidity. The closure
28
is then fitted in place and secured as required, for example by adhesive or by adhesive tape around the container lapping over the adjacent edges of the closure
28
and the envelope
26
. The container
13
can be labelled for shipping or put in a labelled shipping bag.
The contents of the transport container
13
may vary between the following types, as follows:
1. For a cold chain product to be kept as cold as possible during transport, the pre-chilled product is placed in the container
13
with the desired quantity (perhaps two Kgs) of “dry ice”, which is frozen carbon dioxide, in granulated, sliced or chunk form.
2. For a cold chain product to be kept cool, but not frozen, for example at 0 to 8 degrees Celsius, the pre-chilled product is placed in the container with a closed shell of flexible low-density polyethylene closed-cell insulating foam which contains a refrigerant. The refrigerant may be dry ice or a frozen ice mat of polyethylene sheet having pockets containing a frozen aqueous solution of polyethylene glycol. The refrigerant keeps the product cold for a long time, but the insulation of the shell between the refrigerant and the product stops the product from being chilled too much by the refrigerant.
3. For a warm product, the product is placed in the container on its own, or wrapped in additional insulation, or with a closed shell of flexible containing a warmed ice mat of the same construction as described above, but heated to, for example, 20 to 30 degrees Celsius.
When dry ice is used as a refrigerant, this sublimes to carbon dioxide gas at a substantial pressure which percolates molecularly into the closed cells of the polyethylene foam and any layer-to-layer spaces in the roll
18
where it chills the cell walls to its temperature. The carbon dioxide gas is also believed, without prejudice to the present invention, to pressurise and expand the cells of at least the innermost layer of the roll
18
. The outer layers of the roll
18
and the envelope
26
keep the expanded cells within the original thickness of the layer concerned, so that the expansion of the cells is also believed to be two-dimensional in the plane of the layers concerned, and to damage the cell walls. When the dry ice has sublimed away, that inner layer or layers is found to have lost most of its substance and resilience and to be thinner than it was, which reduces the bulk of the container for disposal or recycling.
The used container is readily recycled or disposed of because the block
12
can be quickly be detached from the roll
18
by slitting the envelope
26
around the block, and then breaking the attachment between the block
12
and the roll
18
, followed by flattening the roll
18
. This is readily done even if the roll contains a polyethylene foam shell or a polyethylene ice mat; all components are of polyethylene. The thinning of at least the inner layer of the roll
18
also reduces the bulk of the container prepared for recycling.
It will be appreciated that polyethylene foam is inexpensive in comparison with fabricated polystyrene, gives good protection from mechanical shock and poor handling, and is easy to recycle.
Referring now to
FIG. 4
of the drawings, in a modification of the preferred example, the block
12
described above has been modified to be a rectangular block
32
which has its corners rounded off at
33
.
The block
32
has a substantially rectangular cross section rather than a T-shaped cross section like block
12
.
The single sheet
15
described above has one edge
15
wound around the edge
34
of the block
32
from a starting point
35
, many times around the block
32
and then around itself to build up a multi-layered roll
36
of approximately rectangular cross-section, as clearly seen in FIG.
4
. The edge
16
is attached to the block
32
by adhesive, or double-sided adhesive tape, or by the use of a hot-air gun as the winding proceeds, and this bonding continues after the starting point
35
has been passed to bond each successive layer of the multi-layered roll
36
to its preceding layer. Such bonding also takes place at the edge of the sheet
15
opposite the edge
16
and the block
32
to secure the roll
36
together.
The block
32
and roll
36
are inserted in a pressure envelope (not shown) in the same way as in the preferred example, which stops the block
32
from being pushed out from the end of the roll which it closes. The envelope is preferably of polyethylene and is heat-shrunk in situ to apply pressure to the block
32
and roll
36
.
When the transport container of this modification has been filled with the product to be transported and any refrigerant that is required, it is closed by having its end opposite the block
32
pressed together in a linear closure, and is held in place by a strip of double-sided adhesive tape just inside and around that end.
Claims
- 1. A transport container comprisingan insulating block; a plurality of layers of flexible insulating foam material forming sides of the container and mounted on the insulating block, which closes one end of the transport container; a heat-shrunk pressure envelope that applies pressure around the exterior of the sides and the block.
- 2. The transport container according to claim 1, wherein the heat-shrunk pressure envelope is a heat-shrunk polyethylene envelope.
- 3. The transport container according to claim 1, wherein the insulating block is formed from stiff polyethylene foam.
- 4. The transport container according to claim 1, wherein sides of the plurality of layers of flexible insulating foam material comprise at least one sheet of said flexible insulating foam material wound a plurality of times around itself to form said plurality of layers of flexible insulating foam material.
- 5. The transport container according to claim 4, wherein said at least one sheet of said flexible insulating foam material is wound a plurality of times around itself and around at least a portion of the insulating block.
- 6. The transport container according to claim 4, wherein at least a portion of the insulating block is attached to at least an outer edge of an outer layer of the plurality of layers of flexible insulating foam material at said one end of the transport container.
- 7. The transport container according to claim 5, wherein said at least one sheet of said flexible insulating foam material is wound a plurality of times around itself and around at least a portion of the insulating block, and another portion of the insulating block is attached to at least an outer edge of an outer layer of the plurality of layers of flexible insulating foam material at said one end of the transport container.
- 8. The transport container according to claim 1, wherein the flexible insulating foam material is of closed-cell low-density polyethylene.
- 9. The transport container according to claim 8, wherein at least one of said plurality of layers of flexible insulating foam material is attached to the insulating block by at least one of heat-bonding, adhesive, or adhesive tape.
- 10. The transport container according to claim 5, wherein a strip of adhesive tape configured to over both said outer edge of an outer layer of the plurality of layers of said flexible insulating foam material and a portion of the insulating block all the way around the insulating block attaches the sides of the transport container to the insulating block.
- 11. The transport container according to claim 1, further comprising closure means for closing the other end of the transport container.
- 12. The transport container according to claim 11, wherein said closure means comprises a further insulating block configured to be attachable to the plurality of layers of flexible insulating foam material to close the other end of the transport container.
- 13. The transport container according to claim 1, wherein the transport container is configured to transport dry ice and a product to be transported.
- 14. The transport container according to claim 1, wherein the closed cells in at least an inner layer of the plurality of layers of the flexible foam insulating material forming the sides of the transport container are pressurized and expanded in a plane of the inner layer by carbon dioxide gas sublimed from the dry ice.
- 15. The transport container according to claim 1, wherein the flexible insulating foam material is of closed-cell low-density polyethylene, and the transport container is configured to transport dry ice and a product to be transported.
Priority Claims (1)
Number |
Date |
Country |
Kind |
9815474 |
Jul 1998 |
GB |
|
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
102e Date |
371c Date |
PCT/GB99/02225 |
|
WO |
00 |
3/16/2000 |
3/16/2000 |
Publishing Document |
Publishing Date |
Country |
Kind |
WO00/03931 |
1/27/2000 |
WO |
A |
US Referenced Citations (7)
Foreign Referenced Citations (9)
Number |
Date |
Country |
3743372A |
Jun 1989 |
DE |
WO 8001791A |
Sep 1980 |
EP |
0157751A |
Oct 1985 |
EP |
2419884A |
Oct 1979 |
FR |
610559A |
Oct 1948 |
GB |
1403771A |
Aug 1975 |
GB |
1482325A |
Aug 1977 |
GB |
2235523A |
Mar 1991 |
GB |
2262155A |
Jun 1993 |
GB |