Note: Descriptions are shown in the official language in which they were submitted.
CA 02236137 1998-04-29
i
i Title: INSULATED TRANSIT BAG
2
3
4 This invention relates to transit bags or pouches for containing
s special contents, and particularly temperature-sensitive
s medicines, for transport of the contents by mail, or by courier.
7
a
9 BACKGROUND TO THE INVENTION
io
ii Many medicines lose their efficacy if kept for more than a few
i2 hours at the wrong temperature. Insulin, for example,
i3 deteriorates if allowed to rise above about 15 degC for more than
i4 an hour or two. As a result, insulin cannot be sent through the
is post. Generally, insulin cannot even be sent by overnight-
is courier.
17
ie Special medical courier services are available, but they are
is inordinately expensive for everyday items. Persons who have need
20 of temperature-sensitive medications, therefore, when travelling,
2i have to have the medications made up by a local pharmacist. Such
2z persons would much prefer their prescriptions to be made up by
23 their home pharmacist, i:E only there were an inexpensive means
z4 for transporting the prescriptions.
zs The invention is aimed at providing a transit bag that can
27 contain a prescription quantity of insulin, and which is
ze sufficiently thermally insulated to enable the insulin to be
2s maintained at a temperature of less than 15 degC, during transit,
3o for a period of about two days. The invention is aimed at
3i providing a bag which is also light in weight, and inexpensive to
32 manufacture.
33
34 As will be apparent from the descriptions herein, the bag can be
3s designed for the transport of items other than insulin
3s prescriptions.
37
38
3s GENERAL FEATURES OF THE :INVENTION
4i The material from which 'the bag of the invention is made is a
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2
i composite or lamination of a plastic bubblewrap sheet and
2 aluminum foil. The aluminum foil is bonded or welded to the
3 bubbles of the plastic bubblewrap sheet.
4
s The composite sheets are arranged one inside the other, with the
s aluminum of the inner composite sheet facing inside, and the
aluminum of the outer composite sheet facing outside. The
a composite sheets are welded or otherwise secured together at the
9 edges to form a pouch, and an open mouth is left for inserting
io the temperature-sensitive contents. The mouth can be welded
m closed, or otherwise closed, after the contents are inserted.
iz
i3 The bubblewrap material provides excellent thermal insulation, in
i4 that air is trapped inside the bubbles. Also, because the
is aluminum foil is laminated to the bubbles, the spaces between the
is bubbles are also confined, and the air is trapped in those spaces
m too. (Still air is, of .course, one of the best insulators
ie known.) The aluminum foil provides protection against radiant
is heat transfer. The aluminum foil also provides structural
2o robustness to the outside of the bag, as a protection against the
2i inevitable minor knocks 'that occur during transport and handling.
2z It may be noted that although the aluminum is thin, it is
i3 structurally well-supported, because the bubblewrap material
24 provides many surfaces that lie at right-angles to the plane of
Zs the foil.
26
2~ As will be explained, the bag can be designed to be inflated,
is after the contents are inserted, which provides good structural
z9 rigidity, good shock-absorption, and improved thermal insulation.
3o Even so, the bag is light in weight (which of course is important
3i in a transportation bag) and inexpensive to manufacture and use.
32
33 The inside aluminum foil provides a robust surface against which
34 the contents can bear directly. The inside of the bag, though
35 mechanically robust, generally does not need to be liquid-tight,
3s because liquid medicines, and other liquids being transported,
3~ would in any case be placed in a liquid-tight sachet or other
3a suitable container prior to being placed in the bag. On the
39 other hand, by configuring the bubble material in different ways,
4o as will be explained, the inside of the bag can be liquid-tight
4i if desired.
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3
1 The bag is not (quite) light-tight. However, the bag provides
z excellent protection against, for example, U/v and other
3 radiation to which some items can be sensitive. In fact, the use
a of the bag, with its metal shielding, might make it difficult for
authorities to detect some illegal substances. Where that is a
s possibility, bags containing approved contents might be provided
with pre-cleared-customs identification. The bag as described
a herein is suitable for this function, in that it is easy for the
9 designer to ensure that any tampering with the sealed bag, either
to though the metal itself, or through the sealed edges, would
11 inevitably be apparent.
lz
13
14 DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
is By way of further explanation of the invention, exemplary
l embodiments of the invention will now be described with reference
18 to the accompanying drawings, in which:
19
zo Fig 1 is a pictorial view of a thermal bag that embodies the
zl invention, the bag being shown open and ready to receive
zz contents;
z3 Fig 2a is a diagram of the configuration of a sheet that is
a
24 composite of the babble-wrap material and aluminum foil,
from which the bag of Fig 1 is made;
zs Fig 2b is a diagram of the configuration of an alternative
z~ composite;
za Fig 2c is a diagram of the configuration of an alternative
z9 composite;
3o Fig 3 is a pictorial view of some components of the bag, shown
at
31 a stage during manufacture;
3z Fig 4 is a cross-section on line 4-4 of Fig 1;
33 Fig 5 is a cross-section on line 5-5 of Fig 1, and shows the
bag
34 at a subsequent stage of manufacture;
Fig 6 is a pictorial view similar to Fig 3, of some components
of
3s a second bag that embodies the invention;
3~ Fig 7a is a cross-sectional view, showing the mouth of the
second
38 bag;
39 Fig 7b is the same view as Fig 7a, and shows the bag in a fully
no closed condition;
41 Fig 8 is the same view as Fig 5 of a third bag that embodies
the
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1 invention;
z Fig 9 is the same view as Fig 1 of a fourth bag that embodies the
3 invention.
4
s The apparatuses shown in the accompanying drawings and described
s below are examples which embody the invention. It should be
noted that the scope of the invention is defined by the
a accompanying claims, and not necessarily by specific features of
s exemplary embodiments.
to
11 The bag 20 shown in Fig 1 is suitable for the containment, during
lz transportation, of thermally-sensitive items, such as medicines
13 and perishable materials.
14
15 The material from which the bag is made is shown in more detail
is in Figs 2a,2b,2c. The material itself is conventional, and is
1~ based on the common polyethylene bubble-wrap material. In Fig
la 2a, a layer 60 of aluminum foil, which is typically about 0.002
is inches thick, is provided with a film 62 of polyethylene, which
Zo is about 0.003 inches thick. The plastic film 62 is in intimate
21 bonded adherence to the aluminum foil layer 60.
2z
z3 The combined plastic-aluminum sheet 63 is welded to a bubble
i4 sheet 64 of plastic film, by passing the bubble sheet and the
25 plastic-aluminum sheet between rollers, under such conditions of
2s heat and pressure as will cause welding. The bubbles 65 are
z~ formed in that the roller against which the bubble sheet 64
2e contacts is provided with many recesses, each with a vacuum
z9 supply, into which the film of the bubble sheet is drawn.
3o Composite sheet 67 is the result of welding the plastic-aluminum
31 sheet 63 to the bubble sheet 64.
32
33 The bubbles 65 have a diameter of about 0.4 inches, and are
34 arranged in regularly-pitched rows.
3s In Fig 2b, a composite sheet like the sheet 67 of Fig 2a is
3~ provided with a backing sheet 68 of plastic film. The backing
3a sheet 68 is welded to the tops of the bubbles 65, again by
3s passing the composite sheet 67 and the backing sheet 68 between
4o rollers under conditions of heat and pressure. Now, the backing
41 sheet 68 is compressed between the roller and the tops of the
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1 bubbles 65, whereby some skill is needed to ensure that the
z backing sheet 68 adheres properly to the tops of the bubbles, but
3 such skill is within the competency of a skilled manufacturer.
4
5 The final composite sheet: 69 in Fig 2b can be used in a bag that
s embodies the invention, as can the composite sheet 67 of Fig 2a.
a Fig 2c shows another variation. Here, a backing sheet 68 and a
9 bubble sheet 64 are pressed together by passing the two films
to between rollers, under conditions of heat and pressure, as
11 described. Then, the plastic-aluminum sheet 63 is pressed onto
lz the tops of the bubbles, again as described. The resulting
13 composite sheet 70 can also be used in a bag that embodies the
14 invention.
is Other variations to the manner of arranging the sheets are also
1~ possible. For example, i~wo of the composite sheets as shown in
la Fig 2a can be pressed together, bubble-to-bubble, to form a
i9 single bonded sheet.
zl As shown in Fig 3, the bag 20 is made from an outer composite
zz sheet 27 and an inner composite sheet 28. Whether the composite
z3 sheet is the sheet 67 of Fig 2a, the sheet 69 of Fig 2b, or the
z4 sheet 70 of Fig 2c, or some other variation, generally the
zs designer will prefer to use the same type of sheet throughout.
zs In making the bag, the outer composite sheet 27 and the inner
z~ composite sheet 28 are assembled with the respective plastic base
ze layer 23 sides of the sheets together, i.e with the aluminum foil
zs 25 sides of the sheets outermost.
31 A crease 29 is made in the outer and inner composite sheets
3z 27,28. The crease 29 is folded over, until all four thicknesses
33 of the sheets overlie each other.
34
The composite sheets are welded together along the left and right
3s side margins 30,32, as shown in Fig 4, thus forming the sheets
37 into a rectangular pouch or bag, which is closed on three edges,
3a and has an open mouth 34 on the fourth edge. The top thickness
39 35 of the bag comprises half of the inner composite sheet 28 and
4o half of the outer composite sheet 27, and the bottom thickness 36
41 of the bag comprises the other halves of the composite sheets.
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s
1 The aluminum foil of the outer composite sheet faces outwards,
2 and the aluminum foil on the inner composite sheet faces inwards
3 and lines the inside of i;he bag.
4
s It may be noted from the drawings that the aluminum foil 25 of
s the inner composite sheen 28 does not extend to the edges of the
bubbles 24 of the inner sheet. The aluminum foil of the inner
s sheet is short, and leaves bubble-exposed margins 37 to left and
9 right of the inner composite sheet. In respect of the outer
to composite sheet 27, there are no bubble-exposed margins, but
11 rather the aluminum foil 25 of the outer sheet covers the whole
12 area of the bubbles of t)ze outer sheet, and is co-extensive with
13 the base layer 23 of the outer composite sheet.
14
is Because the aluminum foi:L 25 of the top and bottom halves of the
is inner sheet 28 does not extend to the edge of the inner sheet,
lz when the left and right margins 30,32 of the top and bottom
la thicknesses 35,36 of the bag are squeezed together, it is the
19 respective plastic base layers 23 of the inner and outer
zo composite sheets 27,28 that come together in direct contact
21 (Fig 4). Thus, at the margins 30,32, the aluminum is not present
2z between the sheets, whereby the plastic of the inner and outer
23 sheets of the top and bottom thickness of the bag can all be
z4 welded together.
zs
2s The side margins of the bag are sealed and secured as described
2z above. The mouth of the bag 20 is also sealed and secured, in a
2a manner as will now be described.
29
3o In the bag depicted in Fig 1, the inner composite sheet 28 has
31 been cut shorter (lengthwise) than the outer composite sheet 27,
s2 and, as shown in Fig 5, the end-edges of the inner sheet are
s3 secured to the outer sheet by means of adhesive tape 43. (The
34 tape 43 is not shown in Fig 1.) To seal the bag after the
ss contents have been inserted, the top and bottom portions of the
ss outer layer can be pressed and welded together. In shown in
3~ Fig 5, the adhesive tape 43 is provided to guide the items to be
3a placed in the bag into the correct place: if the tape were
39 omitted, a careless person might insert the item between the
4o inner and outer composite sheets, rather than between the two
41 halves of the inner composite sheet.
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1 Figs 6,7a show an alternative arrangement of the sheets at the
2 mouth of the bag. As shown in Fig 6, the aluminum foil is absent
3 from the ends of the inner composite sheet, thus exposing the
4 bubbles at end-margins 38,39, just as the bubbles at the side
s margins are exposed. As shown in Fig 7a, the inner and outer
6 sheets 28,27 of the top thickness 35 are squeezed and pre-welded
together, at 40, during manufacture of the bag, as are the inner
a and outer sheets 28,27 of: the bottom thickness 36, at 41. Again,
i.t may be noted that the aluminum foil 25 stops short, and leaves
to end margins 38,39 of exposed bubbles of the inner sheet 28.
11
lz After the contents have been inserted into the bag, the bag is
13 sealed. This is done by pressing the pre-welded portions 40,41
14 between heated bars 42, which welds the then-touching plastic
is together. As shown in Fig 7b, after that, the mouth of the bag
16 lies sealed in much the same manner as the side margins of the
1~ bag.
18
is In the alternative shown in Fig 8, a piece of adhesive tape 45 is
2o provided for sealing the mouth of the bag shut after the contents
zl have been inserted. The tape 45 is provided with a peel-off
22 backing strip 46, which is removed just before the tape 45 is
23 folded over and pressed against the aluminum foil 25 in the area
z4 47 of the bottom 36 of the bag. It may be noted that flat
zs aluminum foil is well suited to being adhered to by the tape.
26
2~ Also, in Fig 8, it may be noted that the bag is made from a
za single composite sheet 48, which is doubled and folded over, as
z9 shown, to form the inner and outer sheets 28,27 of the top and
3o bottom thicknesses 35,36 of the bag. In this case, the aluminum
31 foil 25 is discontinuous,, in that the foil does not extend over
32 the bottom lip 49 of the mouth of the bag.
33
34 It will be noted that, lIl the bags as illustrated, the aluminum
3s foil forming the inside :Lining of the bag is physically isolated
36 from the aluminum foil forming the outside of the bag. Not only
3~ that, but the inside foi:L is everywhere kept away from the areas
3a where the sheets are squeezed together, and in fact the inner
39 foil is everywhere separated from the outer foil by two full
4o thicknesses of the un-compressed plastic bubblewrap material.
41
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1 Removing the inside aluminum foil from the margins is
z advantageous for two rea:>ons: first, it means the plastic
3 components of the sheets are in direct touching contact at the
4 margins, whereby the plaatic components can be welded together at
s the margins; and second, it allows the inside and outside
s aluminum foils to be kept: everywhere well spaced apart. If the
inside and outside foils were allowed to touch, the resulting
s capacity to conduct heat would destroy much of the insulative
s nature of the bag. Indeed, if the inside and outside foils were
to allowed even to be close together (if, for example, the inside
11 and outside foils were separated only by squeezed bubbles), it
lz can be expected that the insulative properties would decline
13 considerably. As shown in the drawings, the inner and outer
14 foils are kept spaced apart everywhere by two thicknesses of un-
ls crushed bubbles.
16
l Fig 9 shows a means for enabling the space between the inner and
la outer composite sheets to be inflated. The inflating means 50 is
is made up from two sheets of plain plastic film, which are bonded
zo together over most of their area, except for an intermediate
zl narrow strip 52. The inflating means 50 is trapped between the
zz inner and outer composites layers 28,27, as shown in Fig 9. The
z3 mn-bonded strip 52 serves as a tube, through which air can be
za injected into the space 54 between the inner and outer sheets,
zs after the items have been placed in the bag. The inflating means
zs 50 can be withdrawn, prior to sealing the mouth of the bag, or
z~ t:he inflating means can be tucked over, and left in place.
za
z9 Inflating the space 54 b<~tween the base layers of the inner and
30 outer sheets provides a degree of extra packing in the bag,
31 without extra weight or <~ost. The extra air also provides better
3z insulation. Plastic being slightly permeable to air, only a very
33 low inflation pressure can be sustained over time -- but the bag
34 is intended for short-term packaging.
3s When the bag is used by a pharmacist, the pharmacist can affix an
3~ information label to the outside surface of the bag: it may be
3a noted that the outside of the bag comprises aluminum foil, not
39 plastic bubbles, and so :it is easy to fix adhesive labels
ao t:hereto. It is the intention that the bag as described herein
al will be placed in a further envelope, for example in a
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i conventional (cardboard) courier-envelope. Alternatively, the
2 bag as described can be utilised itself as the complete envelope.
3
4 7.'he bag as described herE:in, especially when welded closed,
s provides a tamper-proof enclosure, in the sense that if the
s contents are tampered with, that fact is obvious to the
recipient. Also, a slip of temperature-sensitive material can be
a inserted into the bag, which would indicate to the recipient if
9 the temperature inside the bag had risen above (or fallen below)
io t:hat required to ensure efficacy of the contents.
m
