US 20030019870 A1
The present invention relates to a freight container (1) with controlled inner environment. The container (1) has protruding wall sections (22) adjacent to edges (20, 21) and walls (12, 16, 18) that comprise said protruding wall sections (22) are formed together as one integrated part. An air-filled space is formed between adjacent containers by the protruding wall sections (22). Preferably, the integrated part comprises an inner shell (42) and an outer shell (40) with insulating material in between. The outer shell (40) preferably comprises a polymer material, which is reinforced at the protruding wall sections (22). The protruding wall sections (22) preferably have a rounded-off shape, preferably extend along the entire length of respective edge (20, 21), and preferably are provided on substantially vertical walls (12). The bottom wall (18) and top wall (16) of the container (1) preferably have complementary projections (50) and recesses (52).
1. A container with controlled inner environment comprising:
a case having at least four walls interconnected by edges; and
at least one lid;
whereby wall sections of walls adjacent to at least two of said edges protrude outside main planes of adjacent walls;
and whereby walls comprising said wall sections are formed together as one integrated part.
2. A container according to
an outer shell;
an inner shell fixed within said outer shell;
whereby an interspace is defined by said outer and inner shells; and
insulating material occupying a substantial part of said interspace.
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14. A container according to any of the
15. A container according to
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17. A method of producing a container with controlled inner environment, comprising the steps of:
casting an outer shell with at least three walls interconnected by edges, said outer shell having wall sections of said walls adjacent to at least two of said edges that protrude outside main planes of both adjacent walls;
casting an inner shell;
inserting said inner shell into said outer shell; and
injecting insulating material into an interspace between said inner and outer shell, forming one integrated part.
18. A method of producing a container according to
19. A method of producing a container according to
20. A method of transporting containers with controlled inner environment, comprising the step of:
placing containers side by side;
whereby protruding wall sections of said containers are placed in contact with or in close proximity of a neighbouring container, defining air-filled space between adjacent container walls.
 The present invention relates in general to freight containers and in particular to freight containers with controlled inner environment for transporting sensitive goods.
 In recent years, the amount of transported sensitive goods, especially goods transported by airfreight, has increased considerably. Sensitive goods, such as food, drugs and electronic equipment, imply specific demands concerning the surrounding environment during transportation or storage. In particular, sensitive goods often require a certain temperature. As a consequence, insulated freight containers with temperature regulating equipment have been developed to be able to control the inside temperature even during flight. Such containers preferably possess certain characteristics, such as light weight and minimum heat transfer.
 Previously known containers in the field typically consist of panels interconnected by profiles, see for example the MYX container manufactured by Envirotainer Engineering AB, Sweden. The panels typically consist of insulating material, such as different layers of polymer material. However, the profiles, which form the framework of the container, are typically made of aluminium. Accordingly, the edges of the container consist of metal, with a relatively high thermal conductivity.
 Freight containers according to prior art are adequate in most aspects but still have a number of disadvantages in certain applications. Firstly, the heat transfer through the container walls, in particular at the edges, is non-negligible. This constitutes a problem when temperature sensitive goods are transported, since it increases the cooling demands. Another problem, also concerning heat transfer, is heat transfer between adjacent containers during transport or storage. A number of containers are often provided close to each other during transport or storage, thus saving space, whereby heat is transferred between them, in particular when the different containers have different requested inner temperatures. The mentioned problems make it more difficult to maintain a constant temperature within each individual container. Consequently, the quality of the transported goods can in some cases be jeopardised.
 For airfreight of sensitive goods, the weight of previous containers causes further problems. Containers that partly or entirely consist of aluminium have a not negligible weight. When using such relatively heavy containers, large transport costs are wasted on just transporting the container, since airfreight charging typically is based on weight.
 As for manufacturing of previously known containers, different parts of the container are typically produced separately and then assembled. This results in a relatively time-demanding and expensive manufacturing process.
 During transport, rough handling of containers is often damaging containers. The problem is aggravated due to the fact that features like sharp edges and projecting details, such as handles, are damaged as well as cause damage on adjacent containers. An additional problem is associated with repair of damaged containers. Prior art combinations of materials, designs and/or manufacturing methods make damaged containers very tedious and time-demanding to take care of, since the repair has to be carried out in a number of steps involving e.g. dismounting of the container. Naturally, this type of repair normally cannot be accomplished at the site where the damage occurred. Consequently, the use of the container may be prohibited for a considerable amount of time. The mentioned problems imply high repair expenses.
 Difficulties in transporting several containers at the same time constitute yet another problem. It is often necessary to transport many containers at the same time; side by side as well as on top of each other. Hereby, sliding is a severe problem endangering the safety and quality of the transported goods. As mentioned, containers also often get damaged during this type of transports.
 A general object of the present invention is to provide an improved freight container. There are a number of specific objects of the present invention. An object is to provide a freight container with improved properties as for heat conduction. Less heat transfer through container walls, in particularly edges, as well as between adjacent containers is hereby aimed at. Another object of the present invention is to provide a container of relatively low weight. Still another object is to provide an improved container that is less exposed for damaging and that causes less damage on other containers. Further objects of the present invention are to provide a container that can be manufactured and repaired comparatively fast and inexpensively. Yet other objects are to provide a method of manufacturing freight containers comparatively fast, swift and inexpensively and to provide a method of transporting a number of such containers in a confident way, avoiding sliding.
 The above objects are achieved in accordance with the attached claims.
 A container with protruding wall sections along edges and with walls formed together as one integrated part is provided. The protruding wall sections give rise to an air-filled space between adjacent containers. Hence, heat transfer between walls of adjacent containers is minimised. Another advantage is that presence of protruding wall sections gives protection for container walls, especially protruding features such as handles and locks, and thus results in less damaged containers. Preferably, the integrated part of a container according to the invention comprises shells with insulating material in between. The uttermost shell preferably comprises a polymer material and mentioned protruding edges are reinforced. The material then gives the advantage of minimised heat transfer through container walls, especially edges. A container of relatively low weight is also achieved. Furthermore, both repair and manufacturing is facilitated, implying reduced costs. A preferred embodiment of the present invention has rounded-off edges, which further prevents damage. Moreover, complementary projections and recesses are preferably provided on the uppermost and lowest horizontal wall of the container. This takes care of the problem with sliding during transport of several piled containers.
 Another aspect of the present invention concerns a method of producing a freight container. A container of the described type is efficiently produced by casting an outer and an inner shell separately and then inserting the inner shell into the outer, followed by injecting an insulating material between the shells. An advantage with this method is that container features, such as protruding wall sections, easily can be cast into the shells. The method also enables that several container walls constitute one integrated part.
 Yet another aspect of the present invention concerns a method of transporting several freight containers. The containers are placed side by side, whereby protruding wall sections define air-filled space between adjacent containers, preventing heat transfer.
 The invention, together with further objects and advantages thereof, may best be understood by making reference to the following description taken together with the accompanying drawings, in which:
FIG. 1 illustrates an embodiment of a freight container according to the invention,
FIG. 2 illustrates an embodiment of the container of FIG. 1 with the lid/top wall removed,
FIG. 3 is a flow diagram illustrating general steps of a method of manufacturing a freight container according to the invention,
FIG. 4 illustrates a number of containers according to the embodiment illustrated in FIG. 1 provided adjacent and/or on top of each other, and
FIG. 5 illustrates parts of an embodiment of the container of FIG. 1, used to control the inner environment of the container.
 Throughout the present disclosure, an “edge” is intended to be the connection between two planes, i.e. an edge extends generally in one dimension. An edge can extend vertically as well as horizontally. A “corner” is intended to be a connection of at least two edges.
 A preferred embodiment of the present invention will now be described with reference to FIG. 1-5. Some variants and modifications are also described. However, the claimed subject matter should not be limited to these exemplifying embodiments, but only be defined by the patent claims.
FIG. 1 shows the outside of a freight container 1 in accordance with the present invention. The container 1 is formed as a case 10, consisting of six walls 12, 16, 18, of which four are side walls 12 (two are visible in FIG. 1), one is a top wall 16 and one is a bottom wall 18 (not visible in FIG. 1). The walls 12, 16, 18 are interconnected by edges 20, 21. There is a main lid 30 provided in the top wall 16 of the case 10 providing access to the inner environment of the container 1. There is also a small lid 32 providing access to an icebox 64. The container 1 is provided with handles 34 and locks 36. In one container side wall 12, a battery unit 38, which is a part of a temperature control device, is provided. Wall sections 22 adjacent to each of the four vertical edges 20 (of which three are visible in FIG. 1) are protruding outside the main planes of the two adjacent vertical side walls 12.
 A major advantage with said protruding wall sections 22 appears when positioning one container juxtaposed to another. This is illustrated in FIG. 4, where containers 1, according to the embodiment of the invention illustrated in FIG. 1, are shown. The containers are placed side by side as well as on top of each other. An air-filled space 24 is then provided between adjacent containers 1. Heat transfer by direct heat conduction between containers 1 is efficiently prevented by the air-filled space 24. Furthermore, air that is cooled or heated by a container side wall 12 starts a convection, which removes the heat/cold from the container vicinity. The space 24 thus serves as a type of insulation, considerably increasing the possibilities of successfully controlling the inner environment of the container 1 as for temperature. In this way, the severe problem of heat transfer between adjacent containers 1 is avoided. A further advantage with the protruding wall sections 22 is that sensitive parts of the container 1 are better protected from damage caused by contact with adjacent containers 1 and/or other objects. The protruding wall sections 22 are typically the first parts of a container 1 that will get into contact with surrounding equipment. Particularly, it is very advantageous that protruding details, such as handles 34 and locks 36, are protected from damage.
 In a preferred embodiment, the protruding wall sections 22 are reinforced to make the container 1 even more resistant to rough handling and damaging circumstances. In the illustrated embodiment, all vertical edges 20 protrude 5 mm outside the main plane of adjacent walls 12 and the protruding wall sections 22 extend along the entire length of respective edge 20, 21. Other embodiments may comprise cases where the protruding wall sections 22 protrude more or less. However, a preferred minimum protrusion distance for providing an efficient convection space would be 4 mm outside said main plane. Embodiments within the scope of the invention may also comprise cases where less than all vertical edges 20 are provided with protruding wall sections 22. Preferably, at least two vertical edges have protruding wall sections 22, though. There may also be embodiments with horizontal edges 21 provided with protruding wall sections 22. Furthermore, embodiments of the invention may comprise cases where at least one protruding wall section 22 does not extend along the entire length of the edge 20, 21. However, such modifications do not alter the general functionality of the container 1 and thus lie within the scope of the invention.
 In a preferred embodiment of the invention the protruding wall sections 22 and thus the vertical edges 20 have a rounded-off shape. Rounded-off edges 20 further minimise the damage on adjacent containers 1. They also prevent adjacent containers 1 from getting caught on each other. The edge radius preferably exceeds 3% of the width of any of the adjacent vertical walls 12 in order to provide a useful edge curvature.
 In FIG. 2, the inside and inner environment of a container 1 in accordance with the invention is shown in a cut through view obtained by removing the top container wall, including the lids, whereby the bottom wall 18 is seen. Here, the structure of the container case 10 is visible. The container case 10 comprises in this embodiment an outer shell 40 and an inner shell 42. An interspace 44 between the shells 40, 42 is filled with an insulating material.
 In the embodiment illustrated in FIG. 2, the five container walls 12, 18 constitute one integrated part. This solution is enabled by the choice of material of the container 1 and the manufacturing method. The outer shell 40 here consists of vinyl ester reinforced by glass fibre, kevlar and carbon fibre. An additional reinforcement by additional layers of kevlar is used at the protruding wall sections 22. The inner shell 42 consists of polyester reinforced by glass fibre and carbon fibre. In the interspace 44 between said outer shell 40 and said inner shell 42 the insulating material polyurethane is provided. As mentioned, the casting of polymer material enables a container 1 to be formed as substantially one integrated part. Features such as handles 34 and locks 36 can easily be recessed into the container walls 12, 16, 18 resulting in absence or a minimum of details projecting outside the main planes of the walls 12, 16, 18. In this way, containers 1 are less damaged and also cause less damage on adjacent containers 1 during storage and transport. Furthermore, polymer material facilitates repair of containers 1 according to the invention. Repair can be carried out swift and inexpensive by adding new polymeric material onto the damaged container area. Another advantage is that containers 1 according to the present invention have a minimum of heat transfer to the surrounding through their walls 12, 16, 18, since metal profiles are not needed to maintain the structure rigidity of the container 1. Even the edges 20, 21 are in this case made of a polymer material.
 There are obviously variants of the constructional features described above. The containers 1 can comprise other materials but with at least one shell 40, 42, at least partly comprising polyester, polyvinyl ester, glass fibre, carbon fibre or kevlar or another polyestric or non-metallic material. However, a preferred embodiment has an outer shell 40 that comprises a polymer material.
 The manufacturing of the container is preferably performed according to another aspect of the present invention, generally illustrated by FIG. 3. The container 1 in the illustrated embodiment as well as in other embodiments covered by the present invention may be effectively produced according to the following four main steps 102, 104, 106, 108 between a start step 100 and a stop step 1110.
 1. Casting an outer shell 40 that comprises the desired outer features.
 2. Casting an inner shell 42, which is to constitute the innermost part of the container case 10.
 3. Inserting the inner shell 42 into the outer shell 40. Preferably, the two shells 40, 42 are connected to each other.
 4. Injecting insulating material into an interspace 44 between the shells 40,42.
 As mentioned, this manufacturing method is intimately connected to the features of the container 1. An outer shell 40 can be cast in a mould shaped to achieve the described protruding wall sections 22. The casting steps are preferably performed with a polymer material. Preferably, an additional step of reinforcing the protruding sections 22 with polymer material is performed to further improve the stability and robustness of the container 1. The above steps 102, 104, 106, 108 constitute a comparatively fast, swift and inexpensively way to produce a container 1 with controlled inner environment according to the present invention. Naturally, there may be embodiments of the present invention that have additional shells cast and inserted between said inner and outer shells 40, 42. There may also be more than one interspace between the shells 40, 42.
 Some prior art containers may present edges unintentionally comprising protruding wall sections. For instance, a container designed according to prior art with aluminium profiles and insulating panels has in fact small protruding wall sections. However, the purpose of these protrusions is to hold the insulating panels. Typically, these protrusions are too small to provide an efficient air space. Furthermore, since also e.g. the edges between the bottom and side wall also presents a protrusion, any air flow between adjacent containers is efficiently prohibited instead.
 When adopting the new manufacturing method of casting an inner and outer shell, the need for the protrusions discussed in the last paragraph vanishes. A natural design of a cast container is therefore provided with planar sides, without protruding sections close to the edges. Anyone skilled in the art would therefore not preserve the detailed shape of the container shell of the profile—panel container, since it is entirely connected to the manufacturing technique. A combination of protruding wall sections and the new manufacturing method is thus not obvious for anyone skilled in the art.
 The preferred embodiment of the invention has six walls 12, 16, 18. However, other embodiments of the invention may consist of a different number of walls 12, 16, 18. At least four walls are necessary to realise the invention, though. It follows that it is also possible that less than five container walls constitute an integrated part. The main lid 30 may in another embodiment comprise the entire top wall 16. Furthermore, other embodiments of the invention may have a lid 30, 32 on another container wall.
 According to yet another aspect of the present invention, containers 1 may be effectively transported by placing them side by side and/or on top of each other, as illustrated by FIG. 4. Hereby, protruding wall sections 22 of different containers are placed in contact or in close proximity of each other, forming an air-filled space 24 between adjacent containers 1. As mentioned, heat transfer between adjacent containers is in this way prevented. Moreover, container features, such as handles 34 or locks 36, are well protected.
 The preferred embodiment of the invention is, as illustrated by FIG. 1 and 4, provided with complementary recesses 52 and projections 50. The top wall 16 is provided with four recesses 52 by the corners. Projections 50, complementary to said recesses 52, are provided on the bottom wall 18. These features facilitate the transport of several containers 1, since they can be piled upon each other in a convenient way, illustrated by FIG. 4. The recesses 52 serve as positioning aid when stacking the containers. The projections 50 have a tapered shape, further facilitating the stacking. Besides to facilitate the stacking, thus making it quicker, the mentioned features result in more solid piles. Hence, the transports of the sensitive goods become safer. The projections 50 have a height, enough for allowing a fork-lift truck to enter its fork below the bottom wall 18.
 The container 1 of the present embodiment is intended to be used for temperature controlled freight, preferably by air. In FIG. 2, some parts are visible, which serves for the provision of a controlled inner environment. An inner main wall 46, consisting of a vacuum panel and presenting a considerably lower heat conduction, divides a main goods compartment 70 from the cooling arrangements. The cooling arrangements have typically a temperature of −78° C. and a normal temperature of the main goods compartment could be e.g. +5° C. It is thus obvious that every improvement on heat insulation is welcome. The inner main wall is insulating, typically made of an insulating material or by a double walled, evacuated board. Furthermore, in a preferred embodiment, the inner shell 42 is provided with recesses for receiving the edge parts of the vacuum panel 46. The edges of the vacuum panel exhibit the highest heat conduction of the entire panel, and by hiding these parts into recesses of the inner shell 42, the heat conduction from the cooling arrangements via the edge of the vacuum panel into the main goods compartment is reduced significantly.
 An inner divisional wall 47 defines an ice box opening 49 leading down to an ice box (not shown in this figure). An insulating panel 60, consisting of a vacuum panel and presenting a considerably lower heat conduction, is provided between the ice box opening 49 and the adjacent inner shell 42 wall, providing an additional heat insulation for the battery unit situated in the wall at this position. Temperature measurement means (not shown) are provided for measuring the temperature within the goods compartment at suitable positions.
 A fan unit 48 is arranged at the inner main wall 46 for drawing air from the goods compartment through an inlet opening (not shown) of the inner main wall 46 into an inlet space 63 above the ice box. An insulating layer 62 separates the ice box from this inlet space 63. The inlet space 63 is separated from an outlet space 65 by a flow restriction wall. The air sucked in by the fan unit 48 is pushed through the inlet space down around the ice box and back up to the outlet space 65, during which flow the air becomes cooled by the ice box. The cooled air is then pushed out through an outlet opening 45 in the inner main wall 46 into the goods compartment. Arrangements for distributing the cooled air over the goods compartment are preferably also provided (not shown).
FIG. 5 illustrates some of the parts belonging to the cooling arrangements. The ice box 64 is here shown, together with the insulating panel 60, the insulating layer 62, the inner divisional wall 47 and the flow restriction wall 66. Flow arrows 68 indicate the flow path of air during the cooling down phase in contact with the surfaces of the ice box. The ice box is typically provided with carbon dioxide ice, serving as a cooling agent If the cooling of the goods compartment is sufficient, the fan is stopped and the air flow will also stop. If the air in the inlet space is allowed to be cooled down, a back-streaming through the fan is possible to occur. However, the insulating layer 62 prohibits such air situated on top of the ice box to be cooled down, hence removing the risk for back-streaming. Preferably, the control unit and ice box 64 are provided as modular units, i.e. each of them is mounted in the container case 10 as one piece or module, including all its functions within this module.
 Although the invention has been described herein with reference to specific illustrated embodiments thereof, it should be emphasised that the invention also covers equivalents to the disclosed features, as well as modifications and variants thereof that are obvious to the man skilled in the art. Therefore, the scope of the invention should only be limited by the enclosed claims.