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EP 0 730 558 B1 |
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EUROPEAN PATENT SPECIFICATION |
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Mention of the grant of the patent: |
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29.07.1998 Bulletin 1998/31 |
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Date of filing: 02.12.1994 |
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International application number: |
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PCT/DK9400/452 |
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International publication number: |
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WO 9515/289 (08.06.1995 Gazette 1995/24) |
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A REFRIGERATED CONTAINER
KÜHLCONTAINER
CONTENANT REFRIGERE
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Designated Contracting States: |
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DE DK IT |
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Priority: |
02.12.1993 DK 134793
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Date of publication of application: |
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11.09.1996 Bulletin 1996/37 |
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Proprietor: MAERSK CONTAINER INDUSTRI AS |
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6360 Tinglev (DK) |
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Inventor: |
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- RAUN, Niels, Peter
DK-6200 Aabenraa (DK)
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Representative: Wittrup, Flemming et al |
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c/o Hofman-Bang & Boutard, Lehmann & Ree A/S,
Hans Bekkevolds Allé 7 2900 Hellerup 2900 Hellerup (DK) |
(56) |
References cited: :
EP-A- 29 229 EP-A- 348 629 DE-A- 1 804 739 FI-A- 8 901 720
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EP-A- 64 712 EP-A- 367 275 DE-C- 2 939 887 SE-B- 467 107
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Note: Within nine months from the publication of the mention of the grant of the European
patent, any person may give notice to the European Patent Office of opposition to
the European patent
granted. Notice of opposition shall be filed in a written reasoned statement. It shall
not be deemed to
have been filed until the opposition fee has been paid. (Art. 99(1) European Patent
Convention).
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[0001] The present invention concerns a double-walled refrigerated container having an inner
cladding and an outer cladding comprising horizontal and vertical, substantially plane
sheet members to form the internal and external, respectively, wall, roof and bottom
faces of the claddings as well as an intermediate, bonded insulation layer of plastics
foam, said sheet members of the outer cladding being attached to the load receiving
frame of the container, which comprises upper and lower longitudinal girders as well
as upper and lower transverse girders and vertical corner posts at the gables, the
lower longitudinal girders being made of sheet members which, seen in cross-section,
are smoothly, openly bent profiles, such that the thickness of the insulation layer
in the transition between side wall and bottom substantially corresponds to or is
greater than the thickness of the side wall insulation layer.
[0002] Today refrigerated containers of the type mentioned above are widely used for oversea
transportation of food products which must be kept cooled at temperatures within very
narrow temperature ranges depending upon the nature of the transported goods. These
may in particular be meat, fruit or vegetables. Therefore, strict requirements are
made with respect to the tightness and the insulation capacity of the container during
use for an extended period of time. Also, it is desired to utilize the transport volume
of the container as well as possible within the given maximum outer dimensions of
the container and particularly in view of the insulation capacity, strength and weight
of the refrigerated container. These are factors which are of decisive importance
for the transport factors which are of decisive importance for the transport earning
capacity when using the refrigerated container in question. It should also be mentioned
that the maintenance costs of the refrigerated container should be kept as low as
possible.
[0003] EP-B-0 064 712 discloses a refrigerated container of the type mentioned in the opening
paragraph comprising an outer cladding of corrugated wall sheets, where the vertical
corrugations of the sheets are terminated inwardly spaced from the sheet rim. The
external wall sheets are connected with the upper and lower longitudinal girders and
the corner posts by encircling weld seams. As shown in the drawing, the container
bottom is supported by underlying, transverse, strong profiles which are connected
with the lower longitudinal girders.
[0004] WO 88/07485 discloses a refrigerated container having a self-supporting floor structure
comprising a plane steel floor sheet, an upper extruded T-floor of aluminium and an
intermediate, bonded insulation layer of high density foam, such as polyurethane foam
having a density from 80 to 90 kg/m
3. This document exclusively provides teachings for the construction of the floor of
the refrigerated container, and thus not for a strong and tight construction of the
entire refrigerated container as such.
[0005] EP-A-0 348 629 discloses another refrigerated container having a self-supporting
bottom structure including a plane bottom sheet, an upper extruded T-floor of aluminium
and an intermediate, bonded, foamed insulation layer. As shown in the drawing, the
longitudinal girder comprises a stiffening L-profile which is coextensive with the
longitudinal girder and is positioned inside the insulation. Nothing is said about
the longitudinal joints between the longitudinal girder and the bottom sheet and the
external side sheets, and thus nothing about how to obtain a strength-imparting construction
of the entire refrigerated container as such.
[0006] In spite of the knowledge of the two last-mentioned documents there is today no refrigerated
containers in the market which comprise a self-supporting bottom structure having
a plane bottom sheet which is free of strong downwardly extending and transversely
extending corrugations which provide the desired strength of the container bottom,
or which are free of strong transversely extending, underlying I-profiles which have
to be welded or riveted to the lower longitudinal girders by time-consuming operations,
or refrigerated containers which are free of inner, longitudinal stiffening profiles
in the insulation foam at the transition between bottom and side wall. Of course,
these downwardly extending corrugations or underlying I-profiles undesirably occupy
a not insignificant part of the internal, effective transport volume of the refrigerated
container corresponding to the corrugations or the height of the profiles, if, other
things being equal, the insulation capacity of the container bottom is to be maintained.
In the known refrigerated containers the thickness of the insulation layer in the
bottom is frequently reduced, however, in order to obtain an inner transport volume
in the refrigerated container as effective as possible, but this consequently results
in a significantly deteriorated insulation capacity of the container bottom. The use
of longitudinal stiffening profiles in the insulation foam results in undesirable
"thermal bridges" in the transition between the bottom and the side wall.
[0007] Further, it is time-consuming and cumbersome to mount the profiles, in particular
because of the subsequent long foaming of the insulation layer in the area around
the profiles and in cavities which are formed between the profiles and the sheet members
on which the profiles are mounted. Frequently, considerable areas are left unfoamed,
causing an additionally diminished insulation capacity.
[0008] Accordingly, the object of the present invention is to provide a refrigerated container
of the type mentioned in the opening paragraph which has an optimum utilization of
the internal effective transport volume of the refrigerated container, and which is
simultaneously both diffusion-tight, strong and has an optimum insulation capacity
in particular at the bottom and the transition between the bottom and the side walls
also after an extended period of use.
[0009] The double-walled refrigerated container of the present invention is characterized
in that said intermediate insulation layer extends uninterruptedly through the transition
between side wall and bottom wall, in that all joints between the sheet members of
the inner cladding are all-welded to provide a completely diffusion-tight, strong
and rigid inner shell, and in that the sheet members of the outer cladding, which
form the bottom face or the sheet members of the lower longitudinal girders, comprise
longitudinal, downwardly extending corrugations which extend close to the joint between
said sheet members.
[0010] This structure provides a refrigerated container which has a particularly low weight
and high insulation capacity as well as a maximum internal, effective transport volume
in relation to the known refrigerated containers. The inner cladding and the outer
cladding exclusively comprise sheet members, and the container is thus free of substantial
protruding parts or profiles which either extend longitudinally inside the insulation
foam, or protrude from the outer side of the container thereby occupying space, and
which were necessary in the past to stiffen the container bottom transversely. Further,
maximum insulation capacity is maintained at said transitions without thermal bridges.
[0011] Since all joints with the sheet members of the inner cladding are all-welded the
inner cladding will serve as a load receiving, strong and rigid inner shell in use.
Both the inner cladding, the outer cladding and the frame parts can thereby be made
of lighter materials than known before. During use for an extended period of time
the inner cladding of the container will still be diffusion-tight, in contrast to
the known refrigerated containers in which the inner cladding always comprises sheet
members which are riveted or glued together.
[0012] The all-welded inner cladding thus ensures that no water vapour diffusion takes place
from the outside and into the container goods and from the inside and out into the
insulation. Similarly, diffusion of the CFC reduced cell gas from the insulation of
the container into the container goods is prevented.
[0013] The combination of the all-welded inner shell, the smoothly bent shape of the lower
longitudinal girder and the downwardly extending corrugations ensures that the container
can be made free of internal longitudinal profiles extending inside the insulation
foam. In other words, there is provided a strong and rigid refrigerated container
with an optimum insulation capacity, in particular at the bottom and at the transitions
between side wall and bottom.
[0014] Expedient embodiments of the refrigerated container of the invention are disclosed
in claims 2-10.
[0015] The invention will be explained more fully below with reference to the drawing, in
which
fig. 1 is a partially sectional view of the refrigerated container of the invention,
but on a somewhat incorrectly drawn scale to show the annular insulation layer more
clearly,
fig. 2 is an enlarged sectional view through a lower part of the container at the
transition between bottom and side wall,
fig. 3 is a vertical section through the container gable which comprises the doors,
fig. 4 is a horizontal section through the same.
[0016] The double-walled refrigerated container 1 shown in fig. 1 comprises an inner cladding
2 of an aluminium sheet material and an outer cladding 3 of a steel sheet material.
The refrigerated container 1 moreover comprises an intermediate, bonded insulation
layer 4 of extruded polystyrene foam in the bottom and of polyurethane foam in other
parts of the container.
[0017] The inner cladding 2 comprises vertical sheet members 5, 6, which form the internal
wall faces of the inner cladding, as well as horizontal sheet members 7, which form
the internal roof faces. The inner cladding 2 moreover comprises a T-floor 8 of extruded
aluminium profiles welded together. All joints between the sheet members 5, 6, 7 of
the inner cladding and the T-floor 8 are all welded to provide a completely diffusion-tight,
strong and rigid inner shell.
[0018] The outer cladding 3 comprises substantially plane sheet members 9, 10, and 11 of
a steel material to form the external wall, roof and bottom faces. The sheet members
may be provided with transverse, slightly downwardly pressed corrrugations 22 extending
spaced from the longitudinal sheet edges.
[0019] The refrigerated container 1 comprises a load receiving frame which comprises mutually
welded upper and lower longitudinal girders 12, 13 as well as upper and lower transverse
girders 14, 15 and vertical corner posts 16 at the gables. The upper and lower longitudinal
girders 12, 13 are formed of sheet members which, seen in cross-section, are evenly
and openly bent profiles, such that the thickness of the insulation layer in the transition
between side wall and bottom and between side wall and roof substantially corresponds
to or is greater than the thickness of the side wall or roof insulation layer 4. A
maximum insulation capacity is hereby maintained in said transitions without thermal
bridges. In the embodiment shown in fig. 2 the lower longitudinal girders 13, seen
in cross-section, are in the form of a "soft" L-profile so that the bent shape gives
the transition of the outer cladding from vertical to horizontal sheet members the
form of an external bevel, which has a considerably damage-limiting function in the
handling of the container.
[0020] All joints 17 between the sheet members 9, 10, 11 of the outer cladding and the load
receiving frame 13, 14, 15, 16 of the container are all-welded to provide a completely
diffusion-tight, strong and rigid outer shell. Welding may take place e.g. by resistance
or laser welding. However, the joints 17 may also be provided by a combination of
gluing and spot welding, the essential thing being that a diffusion-tight, strong
and rigid outer shell is provided. Gluing may e.g. be effected with polyurethane glue.
[0021] As shown in fig. 2, the lower longitudinal girders 13 comprise a longitudinal, downwardly
protruding slight corrugation 18, which extends close to the joint 17 between the
longitudinal girder concerned and the bottom sheet 11. The longitudinal corrugation
18 protrudes sufficiently down from the bottom to support the container if it is placed
with its bottom directly on the ground, and will simultaneously "push" any small stones
away, without the bottom being deformed. The longitudinal corrugation 18 also contributes
to the desired stiffening of the transition between bottom and side wall.
[0022] In this embodiment the inner cladding and the outer cladding exclusively comprise
sheet members and are substantially free of essential protruding parts or profiles
which either extend longitudinally inside the insulation foam or protrude from the
outer side of the container, including the bottom, in a space-requiring manner. The
container will simultaneously be both more rigid and strong and also have a lower
weight as well as higher insulation capacity in relation to the known refrigerated
containers, and moreover a greater internal transport volume in the refrigerated container
will be obtained. The container also has smooth and clean outer and inner faces. The
diffusion-tight, strong and rigid outer cladding and inner cladding ensures a long
container service life, since the container will not be just as subject to degradation
of the insulation material as the known refrigerated containers, in which most of
the sheet members are riveted or glued to the frame.
[0023] It should be mentioned that the insulation layer 4 may be formed by plastics foam
which have been premanufactured in blocks, which are glued together with the sheet
members of the inner cladding 2 and the outher cladding 3, or which are foamed directly
between the inner cladding 2 and the outer cladding 3 to fix these. The insulation
layer 4 may e.g. comprise extruded polystyrene foam in blocks having a weight of 40
kg/m
3 in the container bottom and polyurethane foam having a weight of 60 kg/m
3 in the walls and of 50 kg/m
3 in the roof. It should moreover be mentioned that the longitudinal girders may be
bent of stainlees steel sheets having a thickness of 3.5 mm, and that the outer sheet
members of the outer cladding may be made of stainless steel sheet material having
a thickness of 0.7-2.0 mm. The sheet members of the inner cladding are made of aluminium
sheet material having a thickness of 3.5 mm.
[0024] At the container gables, e.g. the gable comprising the doors 118, the sheet members
6, 7 and 8 of the inner cladding may be welded to an internal frame 19 of sheet material.
The sheet members 9, 10 and 11 in the outer cladding of the container may be welded
to an external frame at the gable, said external frame being formed by the welded
transverse girders 14, 15 and the vertical corner posts 16. An annular insert of a
resilient material 20 may be interposed between the internal frame 19 of sheet material
and the external strength-imparting profile frame. The inner cladding and the outer
cladding can hereby work slightly with respect to each other because of varying temperature
influences and coefficients of thermal expansion, without involving any risk of leakages
that might reduce the insulation capacity, while obviating galvanic corrosion that
may occur at a metalic connection between inner cladding and outer cladding.
[0025] The container doors 118 may be provided with an annular, inwardly extending knife
or strip 21, which is pressed into a further intermediate insert 20a of rubber or
directly into the resilient insert 20 upon closure of the doors 118. This ensures
particularly reliable sealing of the doors 118.
[0026] Many modifications can be made within the scope of the claims, since e.g. the longitudinal
girders may be bent of sheet members which have many different cross-sectional shapes,
e.g. an arc shape.
1. A double-walled refrigerated container (1) having an inner cladding (2) and an outer
cladding (3) comprising horizontal and vertical, substantially plane sheet members
(6, 7, 8; 9, 10, 11) to form the internal and external, respectively, wall, roof and
bottom faces of the claddings (2, 3) as well as an intermediate, bonded insulation
layer (4) of plastics foam, said sheet members (9, 10, 11) of the outer cladding (3)
being attached to the load receiving frame of the container (1), which comprises upper
and lower longitudinal girders (12, 13) as well as upper and lower transverse girders
(14, 15) and vertical corner posts (16) at the gables, the lower longitudinal girders
(13) being made of sheet members which, seen in cross-section, are smoothly, openly
bent profiles, such that the thickness of the insulation layer (4) in the transition
between side wall and bottom substantially corresponds to or is greater than the thickness
of the side wall insulation layer (4), characterized in that said intermediate insulation layer extends uninterruptedly through the transition
between side wall and bottom, in that all joints (9) between the sheet members (6,
7, 8) of the inner cladding (2) are all-welded to provide a completely diffusion-tight,
strong and rigid inner shell, and in that the sheet members (11) of the outer cladding,
which form the bottom face or the sheet members (12, 13) of the lower longitudinal
girders, comprise longitudinal, downwardly extending corrugations (18) which extend
close to the joint (17) between said sheet members.
2. A double-walled refrigerated container according to claim 1, characterized in that the bent shape of the longitudinal girders (12, 13) gives the transitions
of the outer cladding (3) from vertical to horizontal sheet members (9, 10, 11) the
form of an external bevel.
3. A double-walled refrigerated container according to claim 1 or 2, characterized in that the sheet material of the longitudinal girders (12, 13) has a thickness which
is between 2 and 10 times the thickness of the sheet members (9, 10, 11) of the outer
cladding.
4. A double-walled refrigerated container according to one or more of claims 1-3, characterized in that all joints (17) between the sheet members (9, 10, 11) of the outer cladding
and the load receiving frame (12, 13, 14, 15, 16) of the container (1) are all-welded
to provide a completely diffusion-tight, strong and rigid outer shell.
5. A double-walled refrigerated container according to claim 3, characterized in that the sheet material of the longitudinal girders (12, 13) has a thickness of
3.5 mm, and the sheet members (9, 10, 11) of the cladding have a thickness of between
0.7 and 2.0 mm.
6. A double-walled refrigerated container according to one or more of claims 1-5, characterized in that the insulation layer (4) in the container bottom is formed by polystyrene
foam having a weight of 30-50 kg/m3 and are formed by polyurethane foam having a weight of 40-70 kg/m3 in other parts of the container.
7. A double-walled refrigerated container according to one or more of claims 1-6, characterized in that all said joints (9, 17) are resistance welded.
8. A double-walled refrigerated container according to one or more of claims 1-7, characterized in that the sheet members (9, 10, 11, 12, 13) of the outer cladding are formed by
stainless steel sheet material.
9. A double-walled refrigerated container according to one or more of claims 1-8, characterized in that the inner cladding is formed by aluminium sheet material.
10. A double-walled refrigerated container according to one or more of claims 1-9, characterized in that the longitudinal joints between the internal sheet members (8, 5) of the
bottom and the side walls, seen in cross-section, are free of sharp corners and have
a smoothly curved transition (fig. 2).
1. Doppelwandiger Kühlcontainer (1) mit einer inneren Verkleidung (2) und einer äußeren
Verkleidung (3), der horizontale und vertikale, im wesentlichen ebene Plattenelemente
(6, 7, 8; 9, 10, 11), um die inneren und äußeren, jeweiligen Wand-, Decken- und Bodenflächen
der Verkleidungen (2, 3) zu bilden, sowie eine Verbundisolierzwischenschicht (4) aus
Kunststoffschaum aufweist, wobei die Plattenelemente (9, 10, 11) der äußeren Verkleidung
(3) an dem lastaufnehmenden Rahmen des Containers (1) angebracht sind, der obere und
untere Längsträger (12, 13) sowie obere und untere Querträger (14, 15) und an den
Giebeln vertikale Eckpfosten (16) aufweist, wobei die unteren Längsträger (13) aus
Plattenelementen angefertigt sind, die im Querschnitt stetig und offen gebogene Profile
sind, so daß die Dicke der Isolierschicht (4) in dem Übergang zwischen der Seitenwand
und dem Boden im wesentlichen der Dicke der Seitenwandisolierschicht (4) entspricht
oder größer ist als dieser, dadurch gekennzeichnet, daß sich die Zwischenisolierschicht
kontinuierlich durch den Übergang zwischen der Seitenwand und dem Boden erstreckt,
daß alle Stoßstellen (9) zwischen den Plattenelementen 6, 7, 8) der inneren Verkleidung
(2) durchgehend verschweißt sind, um einen vollständig diffusionsdichten, stabilen
und festen Innenmantel vorzusehen, und daß die Plattenelemente (11) dar äußeren Verkleidung,
die die Bodenfläche der Plattenelemente (12, 13) bilden, oder die unteren Längsträger
sich der Länge nach, nach unten erstreckende Auskragungen (18) haben, die sich nahe
der Stoßstelle (17) zwischen den Plattenelementen erstrecken.
2. Doppelwandiger Kühlcontainer nach Anspruch 1,
dadurch gekennzeichnet, daß
die gebogene Form der Längsträger (12, 13) den Übergängen der äußeren Verkleidung
(3) von den vertikalen zu den horizontalen Plattenelementen (9, 10, 11) die Form einer
äußeren Abschrägung verleiht.
3. Doppelwandiger Kühlcontainer nach Anspruch 1 oder 2,
dadurch gekennzeichnet, daß
das Plattenmaterial der Längsträger (12, 13) eine Dicke hat, die das zwei- bis zehnfache
der Dicke der Plattenelemente (9, 10, 11) der äußeren Verkleidung ist.
4. Doppelwandiger Kühlcontainer nach einem oder mehreren der Ansprüche 1 bis 3,
dadurch gekennzeichnet, daß
alle Stoßstellen (17) zwischen den Plattenelementen (9, 10, 11) der äußeren Verkleidung
und des lastaufnehmenden Rahmens (12, 13, 14, 15, 16) des Containers (1) durchgehend
verschweißt sind, um einen vollständig diffusionsdichten, stabilen und festen Außenmantel
vorzusehen.
5. Doppelwandiger Kühlcontainer nach Anspruch 3,
dadurch gekennzeichnet, daß
das Plattenmaterial der Längsträger (12, 13) eine Dicke von 3,5 mm hat und die Plattenelemente
(9, 10, 11) der Verkleidung eine Dicke zwischen 0,7 und 2,0 mm haben.
6. Doppelwandiger Kühlcontainer nach einem oder mehreren der Ansprüche 1 bis 5,
dadurch gekennzeichnet, daß
die Isolierschicht (4) in dem Containerboden durch Polystyrenschaum gebildet ist,
der ein Gewicht von 30 bis 50 kg/m3 hat, und in anderen Teilen des Containers durch Polyurethanschaum mit einem Gewicht
von 40 bis 70 kg/m3 gebildet ist.
7. Doppelwandiger Kühlcontainer nach einem oder mehreren der Ansprüche 1 bis 6,
dadurch gekennzeichnet, daß
alle Stoßstellen (9, 17) widerstandsgeschweißt sind.
8. Doppelwandiger Kühlcontainer nach einem oder mehreren der Ansprüche 1 bis 7,
dadurch gekennzeichnet, daß
die Plattenelemente (9, 10, 11, 12, 13) der äußeren Verkleidung durch rostfreies Stahlblechmaterial
gebildet sind.
9. Doppelwandiger Kühlcontainer nach einem oder mehreren der Ansprüche 1 bis 8,
dadurch gekennzeichnet, daß
die innere Verkleidung aus Aluminiumblechmaterial gebildet ist.
10. Doppelwandiger Kühlcontainer nach einem oder mehreren der Ansprüche 1 bis 9,
dadurch gekennzeichnet, daß
die Längsstoßstellen zwischen den Innenblechelementen (8, 5) der Boden- und der Seitenwände
im Querschnitt ohne scharfe Kanten sind und einen leicht gekrümmten Übergang haben
(Fig. 2).
1. Contenant réfrigéré à double paroi (1) ayant un placage intérieur (2) et un placage
extérieur (3) comprenant des éléments de paroi horizontaux et verticaux sensiblement
plans (6, 7, 8; 9, 10, 11) destinés à former respectivement les faces de côté, de
plafond et de fond intérieures et extérieures des placages (2, 3), ainsi qu'une couche
d'isolation intermédiaire collée (4) de matière plastique alvéolaire, lesdits éléments
en tôle (9, 10, 11) du placage extérieur (3) étant fixés sur le cadre porteur du contenant
(1), qui comprend des poutres longitudinales supérieures et inférieures (12, 13),
ainsi que des poutres transversales supérieures et inférieures (14, 15) et des montants
d'angle verticaux (16) au niveau des pignons, les poutres longitudinales inférieures
(13) étant faites d'éléments en tôle qui, vus en coupe transversale, sont des profilés
ouverts cintrés de manière légère et franche, de sorte que l'épaisseur de la couche
d'isolation (4) dans la zone de transition entre la paroi latérale et le fond correspond
sensiblement ou est supérieure à l'épaisseur de la couche d'isolation (4) de la paroi
latérale, caractérisé en ce que ladite couche d'isolation intermédiaire s'étend sans
discontinuer sur toute la zone de transition entre la paroi latérale et le fond, en
ce que toutes les liaisons d'assemblage (9) entre les éléments en tôle (6, 7, 8) du
placage intérieur (2) sont réalisées par soudage en continu pour donner une enveloppe
intérieure totalement étanche à la diffusion, robuste et rigide, et en ce que les
éléments en tôle (11) du placage extérieur, qui constituent la face formant fond des
éléments en tôle (12, 13) des poutres longitudinales inférieures, présentent des ondulations
longitudinales (18) s'étendant vers le bas, qui aboutissent tout près de la liaison
d'assemblage (17) entre lesdits éléments en tôle.
2. Contenant réfrigéré à double paroi selon la revendication 1, caractérisé en ce que
la configuration cintrée des poutres longitudinales (12, 13) confère aux transitions
au niveau du placage extérieur (3) entre les éléments en tôle verticaux et horizontaux
(9, 10, 11) la forme d'un biseau extérieur.
3. Contenant réfrigéré à double paroi selon la revendication 1 ou 2, caractérisé en ce
que la tôle des poutres longitudinales (12, 13) a une épaisseur qui se situe entre
2 et 10 fois l'épaisseur des éléments en tôle (9, 10, 11) du placage extérieur.
4. Contenant réfrigéré à double paroi selon l'une ou plusieurs des revendications 1-3,
caractérisé en ce que toutes les liaisons d'assemblage (17) entre les éléments en
tôle (9, 10, 11) du placage extérieur et le cadre porteur (12, 13, 14, 15, 16) du
contenant (1) sont réalisées par soudage en continu pour donner une enveloppe extérieure
totalement étanche à la diffusion, robuste et rigide.
5. Contenant réfrigéré à double paroi selon la revendication 3, caractérisé en ce que
la tôle des poutres longitudinales (12, 13) a une épaisseur de 3,5 mm, et les éléments
en tôle (9, 10, 11) du placage ont une épaisseur se situant entre 0,7 et 2,0 mm.
6. Contenant réfrigéré à double paroi selon l'une ou plusieurs des revendications 1-5,
caractérisé en ce que la couche d'isolation (4) au fond du contenant est constituée
par de la mousse de polystyrène d'un poids de 30-50 kg/m3 et est constituée par de
la mousse de polyuréthane d'un poids de 40-70 kg/m3 dans les autres parties du contenant.
7. Contenant réfrigéré à double paroi selon l'une ou plusieurs des revendications 1-6,
caractérisé en ce que toutes lesdites liaisons d'assemblage (9, 17) sont réalisées
par soudage par résistance.
8. Contenant réfrigéré à double paroi selon l'une ou plusieurs des revendications 1-7,
caractérisé en ce que les éléments en tôle (9, 10, 11, 12, 13) du placage extérieur
sont réalisés en tôle d'acier inoxydable.
9. Contenant réfrigéré à double paroi selon l'une ou plusieurs des revendications 1-8,
caractérisé en ce que le placage intérieur est réalisé en tôle d'aluminium.
10. Contenant réfrigéré à double paroi selon l'une ou plusieurs des revendications 1-9,
caractérisé en ce que les liaisons d'assemblage longitudinales entre les éléments
intérieurs en tôle (8, 5) du fond et des parois latérales, vues en coupe transversale,
sont exemptes d'angles vifs et forment une transition légèrement incurvée (fig.2).