[0001] The present invention relates to a heat-insulating container and more particularly
to a heat-insulating container suitable for the storage or distribution of articles
or substances such as, e.g., an enzyme, coenzyme or reagent whose temperature must
be controlled below a predetermined temperature for a long time.
[0002] Heat-insulating containers made of synthetic resin foams are known. For example,
Japanese Published Unexamined Patent Application No.159271/2000 discloses a heat-insulating
container made of a synthetic resin foam, comprising a box-shaped container body,
a cold insulator and a lid. The cold insulator can be accommodated in the internal
peripheral walls of the lid and container body, such that the condensation formed
on the cold insulator does not drop on a stored product. Registered Japanese Utility
Model No. 3058267 discloses a heat-insulating container comprising a close-bottomed
cylindrical container body made of a synthetic resin foam, and a synthetic resin foam
lid rotatably attached to the opening portion of the container body.
[0003] Many of the heat-insulating containers made of a synthetic resin foam are generally
box-shaped, as is the one disclosed in the above-mentioned Japanese Published Unexamined
Patent Application No.159271/2000. As a result, when, for example, an item to be cooled
and/or a cool storage medium are stored in the container, the weight of the container
may be so heavy that it cannot be transported manually. Further, the container body
is in most cases made of an integral molding of a synthetic resin foam. Accordingly,
the entire volume of the container covered by the lid is the same regardless of whether
it is actually being used as a heat-insulating container or when being transported
or stored merely as a container without any contents, thus securing a space for the
container is a problem when it is not in use. Further, when the container is an integrally
molded article, productivity of the container will be decreased and mold production
cost will be increased sharply when a relatively large-sized article is to be manufactured.
The container disclosed in Registered Japanese Utility Model No. 3058267 is cylindrically
shaped, so that it can be rolled via its peripheral edge portion and thus can be transported
by hand relatively easily when it is heavy. However, since, the container body is
integrally molded, the container has the same problems as those of the box-shaped
container with regard to the securing of storage space and manufacturing cost.
[0004] The containers made of a synthetic resin foam are not as strong as containers or
drums made of non-expanded resin, metal or reinforced paper. Although the synthetic
resin foam containers are superior in heat insulation properties, they are not hardy
enough to withstand long-distance transportation by air, sea or land.
[0005] In view of these problems of the prior art, it is an object of the present invention
to provide an improved heat-insulating container made of a synthetic resin foam which
can perform its intended functions when actually used as a heat-insulating container
regardless of the size of the internal volume and without manufacturing cost increasing,
and which requires far less storage space when not in use.
[0006] It is another object of the present invention to provide a heat-insulating container
made of a synthetic resin foam which can withstand external impacts so that it can
be reliably used in distribution routes such as by air cargo.
[0007] The heat-insulating container of the present invention basically comprises a disc-shaped
upper lid, a disc-shaped lower lid, and a cylindrical sidewall portion which are all
made of a synthetic resin foam, wherein the cylindrical sidewall portion is a structural
member made up of two or more separate, circumferentially divided pieces. The main
body portion of the container is assembled by attaching the disc-shaped lower lid
to the cylindrical sidewall portion. If necessary, the joints are affixed with an
adhesive tape. An item to be heat-insulated and a refrigerant such as dry ice are
placed in the container, which is then covered by the disc-shaped upper lid and, if
necessary, the circumferential surface of the container is attached with an adhesive
tape, thereby producing a distribution or storage package utilizing the heat-insulating
container of the present invention.
[0008] Since the heat-insulating container of the present invention is generally cylindrical
in shape, it can be easily transported by rolling on its circular edge even if the
contains is heavy. Further, the cylindrical sidewall portion, which forms the main
body portion, can be divided into a plurality of separate pieces, so that the heat-insulating
container, when not being used as such, requires less space for transportation or
storage. Even if the cylindrical sidewall portion is large, the individual separate
pieces can be relatively small, so that their molding requires less time than in the
case of making the container as an integrally formed article. In addition, molded
parts can be cut out of the molds more satisfactorily, and also the material can be
poured into the mold cavities more satisfactorily. Thus, efficiency of molding can
be improved while reducing costs, and the space required for storing the molds can
also be reduced.
[0009] In the heat-insulating container of the present invention, the individual separate
pieces which make up the cylindrical sidewall portion are combined via abutting surfaces
formed on each separate piece such that a convex portion formed on one surface engages
a concave portion formed on the other surface. The circumferential length of each
separate piece is set such that no two abutting portions are located simultaneously
in a vertical virtual plane slicing a center line of the cylinder.
[0010] In this embodiment, the possibility is minimized of a thermal shortcut being formed
on the abutting surfaces of adjacent separate pieces, so that the heat-insulating
properties can be improved. Further, even if a shock is applied to the container during
transport on the edge on one side, the embodiment can reliably prevent the separation
of the abutting surfaces of the separate pieces on the opposite side and the possible
loss of air-tightness.
[0011] In another embodiment of the heat-insulating container of the present invention,
the cylindrical sidewall portion comprises a rib protruding radially inwardly, and
a central bedding with such dimensions as to be locked by the rib. The central bedding
is preferably formed with a number of holes for circulating cold air. In this embodiment,
it is possible to store a heat-insulated item and a refrigerant such as dry ice separately,
the former in a space below the central bedding and the latter in a space above the
central bedding, so that a high cooling efficiency can be obtained for a long time.
Advantageously, a bedding with legs may be placed on the disc-shaped lower lid, in
which case a heat-insulated item can be placed on the bedding. This facilitates the
circulation of cold air effectively, further improving the cooling efficiency. Alternatively,
two central beddings may be provided in two stages, so that the refrigerant such as
dry ice may be placed between them. In this case, different cooling environments can
be created for spaces above and below the refrigerant.
[0012] In yet another embodiment, the cylindrical sidewall portion is further divided into
two or more stages along the center line. In this embodiment, the height of the cylindrical
sidewall portion can be selectively set according to the type or size of the heat-insulated
item that is accommodated. Thus, a useless cooling space can be eliminated and the
cooling efficiency can be improved. Also, multiple central beddings can be easily
placed in multiple stages at intermediate positions.
[0013] In the present invention, the type of synthetic resin foam is not particularly limited.
Examples include a polystyrene resin, a polypropylene resin, a polyethylene resin,
a polyester resin, and a polyurethane resin. From the viewpoint of ease of molding,
strength and impact resistance, the individual components are preferably internal
mold foam articles produced by using prefoamed particles of a polystyrene resin. The
expansion factor can be determined by taking into consideration the desired heat-insulating
performance, container weight, etc, but it should be in the range of from 20 to 100,
preferably from 30 to 60.
[0014] While a container made of a synthetic resin foam is superior in heat-insulating properties,
its resistance to possible external shock might in some cases not be enough, depending
on the kind of distribution environment. To cope with such possible situations, in
another embodiment of the present invention, the heat-insulating container is equipped
with a cylindrical container protector for protecting the heat-insulating container
from external shock. The container protector may be made of any materials such as,
e.g., reinforced paper, resin and metals, as long as they can provide a required strength.
However, paper should preferably be used, for it can easily be disposed of.
[0015] Preferably, the container protector comprises an open-top container body and a lid.
A heat-insulating container containing a heat-insulated item is then housed in the
container body, the lid is placed, followed by sealing the joints by an adhesive tape,
for example. The thus protected heat-insulating container is highly resistant to external
shocks and can withstand a long-distance transportation by air, sea or land. Accordingly,
the heat-insulating container in this embodiment of the present invention can be suitably
used, e.g., for transporting abroad an item in a heat-insulated condition, such items
including enzymes, coenzymes and reagents whose temperature must be controlled below
a certain temperature for a long time during storage or distribution.
FIG. 1A is a plan view of an assembled heat-insulating container;
FIG. 1B is a side elevational view of the assembled heat-insulating container;
FIG. 2A is a sectional view taken on the line a-a of FIG. 1A;
FIG. 2B is a sectional view taken on the line b-b of FIG. 1B;
FIG. 3 is a perspective view of one of separate pieces which form a cylindrical sidewall
portion;
FIG. 4A is a perspective view of a central bedding;
FIG. 4B is a perspective view of a bedding;
FIG. 5A is a schematic plan view of an example of the cylindrical sidewall portion;
FIG. 5B is a schematic plan view of another example of the cylindrical sidewall portion;
FIG. 5C is a schematic plan view of yet another example of the cylindrical sidewall
portion;
FIG. 6A is a schematic plan view of a further example of the cylindrical sidewall
portion;
FIG. 6B is a schematic plan view of a yet further example of the cylindrical sidewall
portion;
FIG. 7 is a perspective view of an example of the container protector;
FIG. 8A is a sectional view of another example of the cylindrical sidewall portion;
FIG. 8B is a sectional view of yet another example of the cylindrical sidewall portion;
FIG. 8C is a sectional view of yet another example of the cylindrical sidewall portion;
FIG. 8D is a sectional view of a further example of the cylindrical sidewall portion;
FIG. 9 shows a graph showing the results of a heat-insulating test.
[0016] The heat-insulating container of the present invention will be hereafter described
by way of several embodiments with reference made to the drawings. FIGs. 1A and 1B
show a plan view and a side elevational view, respectively, of an assembled heat-insulating
container 1. FIGs. 2A and 2B show a sectional view taken along the line a-a of FIG.
1A and a sectional view taken along the line b-b of FIG. 1B, respectively. As shown,
the heat-insulating container 1 comprises a disc-shaped upper lid 10, a disc-shaped
lower lid 20, and a cylindrical sidewall portion 30, each made of a synthetic resin
foam. In this example, the cylindrical sidewall portion 30 is made up of three identically
shaped separate pieces 31 divided at 120° intervals along the circumference. As shown
in detail in FIG. 3, each separate piece 31 comprises arched cut portions 32 and 33
formed on the inside of the upper and lower circumferential edges, respectively. Each
separate piece 31 also comprises a rib 34 on the internal wall surface slightly above
the middle section, protruding radially. One side edge of the internal surface of
each separate piece 31 is provided with a rib 35. The other side edge of the internal
surface of each separate piece 31 is provided with a groove 36 with which the rib
35 can engage in an air-tight manner. Thus, adjacent separate pieces can be assembled
together in an air-tight manner.
[0017] The three separate pieces 31 are put together such that the rib 35 and groove 36
formed on the side edges can abut with each other, thereby forming the cylindrical
sidewall portion 30 mentioned in the present invention. The cylindrical sidewall portion
30 is formed with circular recessed portions 32a and 33a on the inside of the upper
and lower open ends, respectively, of the cylindrical sidewall portion 30. The cylindrical
sidewall portion 30 is further formed with a circular rim 34a slightly above the middle
of the internal wall. The separate pieces 31 are assembled via an abutting portion
S where the concave portion formed on one surface abuts the convex portion formed
on the other surface. As shown in FIG. 5A, no two abutting portions S are located
simultaneously in a vertical virtual plane L slicing along a center line O of the
cylinder. Thus, when an impact is applied to the edge on one side of the cylindrical
sidewall portion 30, the abutting portions S of the separate pieces located on the
opposite side do not easily separate and the loss of air-tightness can be prevented.
[0018] In this example, the disc-shaped upper lid 10 and the disc-shaped lower lid 20 are
discs of substantially the same shape, and their diameter is substantially the same
as the external diameter of the cylindrical sidewall portion 30. The disc-shaped upper
lid 10 may be slightly smaller in diameter. This makes it easier to open the disc-shaped
upper lid 10 when in use, as will be described later. One face of each disc forms
a cylinder portion 11 or 21 with a reduced diameter which is substantially the same
as the diameter of the circular recessed portions 32a and 33a formed at the upper
and lower open ends of the cylindrical sidewall portion 30. Thus, the disc-shaped
upper lid 10 and lower lid 20 are mounted on the cylindrical sidewall portion 30 such
that their cylinder portions 11 and 21 with reduced diameter internally engages the
upper and lower open ends of the cylinder sidewall portion 30 in an air-tight manner,
as shown in FIG. 2A. Thus, in an assembled heat-insulating container 1, the internal
space is isolated from the external space.
[0019] A plate-like central bedding 40 is placed as needed on the circular rim 34a formed
on the internal wall surface of the cylindrical sidewall portion 30, as shown in FIG.
4A. The central bedding 40 is made of an expanded or non-expanded polystyrene resin,
for example, and formed with a number of through holes 41. By placing the central
bedding 40 inside the heat-insulating container 1, its internal space is divided into
a lower space A and an upper space B, as shown in FIG. 2A, and the two spaces are
communicated with each other via the through holes 41. FIG. 4B shows a bedding 45
which is used as needed. It has legs 46 on the back surface so that, when the bedding
45 is placed on the disc-shaped lower lid 20, a ventilating space is formed between
the bedding and the disc-shaped lower lid 20.
[0020] Before use, the cylindrical sidewall portion 30 is assembled first, the bedding 45
is placed inside if needed (not shown in FIG. 2A), and then the disc-shaped lower
lid 20 is attached to the bottom portion of the sidewall portion. When a high degree
of stability is required, the joined surfaces or the seams are sealed by an adhesive
tape (not shown). Then, an item to be heat-insulated, such as an enzyme, is put into
the internal space (the lower space A in the illustrated example), the central bedding
40 is placed, and then a refrigerant such as dry ice is placed thereon (in the upper
space B). Finally, the disc-shaped upper lid 10 is put on the cylindrical sidewall
portion 30, to complete the heat-insulating container 1 in which the heat-insulated
item is accommodated in an air-tight space. The through holes 41 in the central bedding
40 allow cool air to circulate effectively, so that the heat-insulated item can be
stored in a temperature-controlled environment for long hours or days.
[0021] After a certain period of time, the disc-shaped upper lid 10 is removed and the accommodated
item is retrieved. The heat-insulating container 1 after use is transported back or
stored at a different site. The disc-shaped lower lid 20 and the central bedding 40
(and also the bedding 45) can be easily separated from one another. The cylindrical
sidewall portion 30 can also be easily disassembled into the three separate pieces
31. Thus, the heat-insulating container 1 requires far less space when transported
or stored without any contents than when used for its intended functions, so that
the transportation or storage costs can be reduced. Further, since the heat-insulating
container 1 is made up of a number of small parts, molding costs can be greatly reduced
as compared with the case of integrally molding the entire container.
[0022] FIGs. 5A to 5C are plan views schematically showing only the cylindrical sidewall
portion 30. FIG. 5A shows the above-described cylindrical sidewall portion 30. FIG.
5B shows a cylindrical sidewall portion 30 formed by not three but five separate pieces
31a. In this case, too, no two abutting portions S are simultaneously located in a
vertical virtual plane L slicing along the center line O of the cylinder. FIG. 5C
shows a further example which differs from the example of FIG. 5A in that the rib
and groove at the side edges of each separate piece 31b are formed by a tongue 35a
and a groove 36a, respectively, in the so-called tongue-and-groove joint. In this
embodiment, better air-tightness can be obtained, and also the possibility of the
individual separate pieces 31b being separated by an impact can be reduced.
[0023] FIGs. 6A and 6B are plan views schematically showing further examples of the cylindrical
sidewall portion 30. In these examples, the cylindrical sidewall portion 30 is made
up of two or four separate pieces 31. While in these cases two abutting portions S
are simultaneously included in the vertical virtual plane L slicing the center line
O of the cylinder, the cylindrical sidewall portion 30 can be prevented from easily
separating by suitably arranging the manner of engagement in the abutting portions
S, or by affixing an adhesive tape along the periphery of the cylindrical sidewall
portion 30.
[0024] The above-described heat-insulating container 1 may be used as is for the distribution
or storage of a heat-insulated item. However, since the container is made of a synthetic
resin foam, it has problems for strength when used for distribution or storage purposes
for a long time under an impact-prone environment. FIG. 7 shows a cylindrical container
protector 50 which may be suitably used in such cases. As mentioned above, the container
protector 50 may be made of any materials including, e.g., reinforced paper, resin,
and metal, as long as they can provide a necessary strength. Paper is preferable,
for it can be easily disposed of. In this example, the container protector 50 comprises
a container body 51 with an open upper part and a lid 52. The heat-insulating container
1 accommodating a heat-insulated item is placed in the container body 51 and the lid
52 is closed, and, if necessary, the joints are sealed by an adhesive tape (not shown).
In FIGS. 1 and 2, the container protector 50 is indicated by phantom lines. When thus
placed in the protector, the heat-insulating container can be made highly resistant
to external impacts or shocks and can therefore withstand a long transportation by
air, sea or land.
[0025] It may be difficult to remove the disc-shaped upper lid 10 when the heat-insulating
container 1 is accommodated in the container protector 50. This problem can be avoided
by reducing the diameter of the disc-shaped upper lid 10 such that there is a gap
between the container body 51 and the lid.
[0026] FIGs. 8A to 8D show other embodiments of the heat-insulating container 1. In these
embodiments, the cylindrical sidewall portion 30 is further divided into two or more
stages (stages 30a, 30b, and 30c in the illustrated example) along the central axis.
The individual cylindrical sidewall portions 30a, 30b, and 30c are combined into one
piece via a fitting engagement of a circular rib 38 and a circular groove 39 formed
on the upper and lower peripheral edge faces of each sidewall portion. Thus, the cylindrical
sidewall portion 30 can be assembled in a highly stabilized manner while ensuring
a high degree of air-tightness. The air-tightness is further enhanced by the disc-shaped
upper lid 10 and disc-shaped lower lid 20 being likewise joined with the cylindrical
sidewall portions 30a and 30c, respectively, via a circular rib and a circular groove.
The cylindrical sidewall portion 30a, 30b, or 30c in each stage is made up of a plurality
of separate pieces, as in the above embodiments.
[0027] FIG. 8B differs from FIG. 8A in that the bedding 45 is placed inside. FIG. 8C differs
from FIGs. 8A and 8B in that the thickness of the middle cylindrical sidewall portion
30b is different from that of the upper and lower cylindrical sidewall portions 30a
and 30c (In the illustrated example, the middle cylindrical sidewall portion is wider,
but it may be thinner.). This example is advantageous in that the temperature distribution
inside the container can be controlled.
[0028] The example shown in FIG. 8D differs from the others in that two central beddings
40 are attached to the middle cylindrical sidewall portion 30b. In this case, different
temperature environments can be obtained in a lower space A and an upper space B by
placing a refrigerant between the central beddings 40. Further, by making the thickness
of the middle cylindrical sidewall portion 30b greater than that of the upper and
lower cylindrical sidewall portions 30a and 30c, the duration of time before melting
or sublimation of the refrigerant occurs can be advantageously extended.
[0029] FIG. 9 shows the results of a heat-insulating test involving the heat-insulating
container 1 according to the embodiment shown in FIGs. 1 and 2. The heat-insulating
container 1 used had a diameter of 490 mm and a height of 620 mm externally. The thickness
of the disc-shaped upper lid 10, disc-shaped lower lid 20 and cylindrical sidewall
portion 30 was all 50 mm. The internal volume was about 60 L. The material was a polystyrene
resin, with an expansion factor of 50. As a heat-insulated item, two packages each
containing 5 kg of an enzyme (total of 10 kg) were stored in the lower space A. The
central bedding 40 made of an expanded polystyrene resin was placed, and then four
packages each containing 2.2 kg of dry ice (total of about 9 kg) were put into the
upper space B. The container was sealed by putting the disc-shaped upper lid 10 thereon.
[0030] The heat-insulating container 1 was then placed in a reinforced paper drum (container
protector 50) measuring, externally, 520 mm in diameter, 650 mm in height and 10 mm
in thickness (with an internal volume of about 120 L), and the drum was covered by
the lid 51 and sealed by an adhesive tape. The drum thus accommodating the heat-insulating
container 1 was then left to stand outside for a long time at a temperature of about
40°C, and temperature changes in the enzyme were measured. FIG. 9 shows the results.
[0031] As shown in FIG. 9, the temperature of the enzyme was controlled at 0°C or below
for about 75 hours, and it reached 25°C only after 110 hours. When an enzyme is manufactured
in a production plant and exported, e.g., from Japan to Europe or the U.S., a typical
transportation environment and time are 40°C and 100 hours, respectively. When it
is an evaluation yardstick for temperature of the product to be maintained at 25°C
(control temperature) or below, the above-described heat-insulating container is quite
satisfactory.
[0032] Thus, the heat-insulating container of the present invention allows the temperature
of a heat-insulated item to be controlled below a preferable temperature for a long
time. Further, since the heat-insulating container of the present invention is made
up of a plurality of parts, the entire volume of the container can be minimized when
not used as such, so that the space required for the distribution or storage of the
container not in use can be reduced, and molding costs can be reduced as compared
with the case of costs for integral molding.
[0033] All publications, patents and patent applications cited herein are incorporated herein
by reference in their entirety.
1. A heat-insulating container comprising a disc-shaped upper lid, a disc-shaped lower
lid, and a cylindrical sidewall portion which are all made of a synthetic resin foam,
wherein the cylindrical sidewall portion comprises two or more separate pieces divided
along the circumference.
2. A heat-insulating container according to claim 1, wherein the separate pieces are
combined with one another via abutting surfaces formed on each separate piece, the
abutting surfaces comprising a convex portion formed on one surface engaging a concave
portion formed on the other surface, and the circumferential length of each separate
piece is set such that no two abutting portions are located in a vertical virtual
plane slicing along a center line of the cylinder.
3. A heat-insulating container according to claim 1 or 2, wherein the cylindrical sidewall
portion has a rib protruding radially inwardly, the heat-insulating container further
comprising a central bedding with such dimensions as to be locked by the rib.
4. A heat-insulating container according to claim 1, 2, or 3, wherein the cylindrical
sidewall portion is also divided into two or more stages along the center line.
5. A heat-insulating container according to any one of claims 1 to 4, further comprising
a bedding which can be accommodated in the cylindrical sidewall portion.
6. A heat-insulating container according to any one of claims 1 to 5, wherein the synthetic
resin foam is selected from the group consisting of a polystyrene resin, a polypropylene
resin, a polyethylene resin, a polyester resin, and a polyurethane resin, and the
expansion factor is in the range of from 20 to 100.
7. A heat-insulating container according to any one of claims 1 to 6, further comprising
a cylindrical container protector for protecting the heat-insulating container against
external shocks.
8. A heat-insulating container according to any one of claims 1 to 7, wherein the container
is used for heat-insulating an enzyme.