WATERPROOF CONTAINER FOR FUMIGATION

Abstract

The invention relates to a freight container adapted for fumigation. The container comprises a sealing door (20) disposed within an internal volume (3) of the container, said sealing door (20) being provided with a subframe fixed hermetically to the container and defining a second access opening, a door curtain movable relative to the subframe between a closed position in which the second access opening is blocked and an open position, and a sealing element mounted on the subframe and / or on the door curtain such that, when the door curtain is in the closed position, the sealing element is compressed between the subframe and the door curtain. (See Figure 1 for abbreviations.)

Description

Title of the invention: WATERPROOF CONTAINER FOR FUMIGATION TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to a container for the transport of goods, also called a freight container. More specifically, the invention relates to a freight container adapted to be fumigated. STATE OF THE TECHNOLOGY

[0002] Each year, hundreds of millions of freight containers containing goods are shipped worldwide. These containers, along with their cargo, constitute a potential vector for the introduction and spread of harmful organisms that pose a serious threat to a country's agriculture, forestry, and natural resources. Such organisms can also cause losses within the transported goods.

[0003] To prevent this threat, containers and their cargo are generally treated by fumigation. This treatment aims to eliminate any presence of parasites, harmful insects, and bacteria that could damage the cargo or invade the territory of the destination country. Because of these risks, many countries require carriers and shippers to fumigate containers before, and sometimes even after, transport.

[0004] Fumigation consists of introducing a gas or a gas-producing substance, called the "fumigation agent," into an enclosed area in order to destroy harmful organisms. Methyl bromide (CH3Br) and phosphine (PH3) are the most frequently used fumigants. Carbon dioxide (CO2) is a more recent alternative that has the advantage of being compatible with organic farming practices.

[0005] One of the main fumigation methods consists of wrapping the cargo or container with a plastic sheet, thus creating an enclosed area where the fumigant can reach a given concentration over a specific period. Although this method is effective, it has the disadvantage of requiring significant time to install and remove the sheet, which is also discarded after each use.

[0006] Another method consists of sealing all openings, including the door, of the container. However, this method requires unsealing the door after each use, in order to remove the goods and introduce new ones, and sealing it again before each new use, making the operation repetitive and time-consuming.

[0007] In both cases, the presence of fumigant leaks remains a frequent problem. In the first method, leaks can occur, for example, when the tarpaulin is not completely airtight or when it is placed on a porous surface such as sand, rock, wood, or other agglomerated materials. In the second method, leaks can appear if the container door seal is not airtight, which frequently happens because this process is carried out from outside the container.

[0008] These leaks lead to a decrease in the fumigant concentration, reducing the effectiveness of the fumigation process. To compensate for this decrease, it is necessary to regularly inject additional fumigant to maintain the desired concentration throughout the treatment. However, this practice results in overconsumption of fumigant, thus increasing costs and potentially having negative environmental impacts. Description of the invention

[0009] The present invention aims to remedy all or part of the disadvantages of the prior art mentioned above.

[0010] To this end, the invention relates to a freight container adapted for fumigation, comprising a lower wall, an upper wall opposite the lower wall, opposite side walls connecting the upper wall to the lower wall, a front wall and a rear wall, opposite the front wall, each connecting the lower wall, the upper wall and the side walls, the walls together defining an internal volume, the container having a first access opening provided in the front wall and at least one access door to open or close said first access opening, the container being characterized in that it further comprises a sealing door disposed in the internal volume of said container, said sealing door being provided with a counter-frame fixed in a hermetic manner to the container and defining a second access opening extending opposite the first access opening,of a door curtain mounted movable relative to the subframe between a closed position in which the second access opening is blocked and an open position, and of a sealing element mounted on the subframe and / or on the door curtain such that, when the door curtain is in the closed position, the sealing element is compressed between the subframe and the door curtain.

[0011] Thanks to the invention, the container can be switched from a cargo loading configuration to a fumigation configuration simply by moving the sealing door from its open position, into which cargo can be easily introduced, to its closed position, in which a confined space is defined to receive a fumigant with a very low risk of leakage. Conversely, the container can be changed from a fumigation configuration to a goods unloading configuration simply by moving the sealing door from its closed position to an open position in which the goods can be easily extracted.

[0012] In other words, integrating the sealing door into the container eliminates the need for repetitive manual operations, such as covering or sealing, each time it is used. Simply opening and closing the sealing door is all that is required. The container is therefore very easy to use. Furthermore, the design of the sealing door, with the counter-frame fixed to the container, ensures a good level of airtightness, improving fumigation efficiency with a smaller quantity of fumigant, which is both economical and environmentally friendly.

[0013] The container according to the invention can be used in the traditional way, that is, to store goods during their transport on a ship, or "on land" as a storage tank, also called a silo, which can be fumigated. In the latter case, the container can, for example, be installed on a farm to store and treat crops by fumigation, and thus prevent losses caused by insect pests. Due to its airtightness, the container can advantageously be installed outdoors during fumigation, which frees up space in sheltered areas.

[0014] Preferred, simple, convenient and economical characteristics of the container according to the invention are presented below.

[0015] The container may include a fumigation chamber in the internal volume, the fumigation chamber being defined by the lower wall, the upper wall, the side walls and the rear wall, as well as by the sealing door when the door curtain is in the closed position; the container being configured so that, when a pressure in the fumigation chamber is greater than a surrounding pressure of the container, said door curtain is stressed against the counter-frame under the effect of the pressure difference, thus further compressing the sealing element.

[0016] The door panel of the sealing door can be mounted pivoting around a pivot axis substantially perpendicular to the side walls, said door panel extending along the upper wall of the container in the open position so as to fully free the second access opening.

[0017] The sealing door further comprises vertical guide rails extending along the side walls in a direction from the lower wall to the upper wall, the door curtain comprising lower guide members configured to slide in the vertical guide rails when the door curtain is moved between the open and closed positions, each vertical guide rail comprising a main portion extending substantially parallel to the counter- frame and an end portion, on the side of the lower wall, which is brought closer to the subframe relative to the main portion, so that when the door curtain is moved from the open position to the closed position, each lower guide member slides first in the main portion of the vertical guide rails and then in the end portion in which said lower guide member is brought closer to the subframe.

[0018] The sealing door may further include a drive device comprising a drive element, such as a counterweight or a motor, to assist the movement of the door curtain between the open and closed positions and a connecting element, such as a cable, to mechanically connect said drive element to said door curtain.

[0019] The sealing door may further include at least one clamping element for bringing the door curtain closer to the subframe, said at least one clamping element comprising a rod fixed on the door curtain and having a threaded portion, a knurled knob engaging with the threaded portion of said rod, and a clamping piece mounted pivoting and sliding on said rod between the door curtain and the knurled knob, said clamping piece being adapted to at least partially overlap both the door curtain and the subframe when the door curtain is in the closed position and being configured so that when the knurled knob is turned to bring it closer to the door curtain, the clamping piece is first moved along the rod until it comes into contact with both the door curtain and the subframe, and then forces the door curtain, via the rod, to move closer to the subframe.

[0020] The container may include a frame defining said first access opening and on which the access door is hinged, the counter-frame may be fixed on said frame defining the first access opening.

[0021] The counter-frame may comprise profiles assembled together to form an overall U-shaped structure, each of the profiles having an overall L-shaped cross-section, with a first wing fixed to the container frame defining the first access opening and a second wing extending substantially perpendicularly from the first wing towards the interior of said counter-frame.

[0022] The counter-frame may further include a threshold bar connecting free ends of the profiles forming the overall U-shaped structure, the threshold bar being fixed on the container frame defining the first access opening and having a general extension plane substantially parallel to the lower wall of the container.

[0023] The door apron of the sealing door can be formed in one piece. BRIEF DESCRIPTION OF THE FIGURES

[0024] The invention, according to an exemplary embodiment, will be well understood and its advantages will become more apparent upon reading the detailed description that follows, given by way of example and in no way limiting, with reference to the attached drawings.

[0025] Fig. 1 schematically and partially in perspective represents a freight container according to the invention, comprising a sealing door having a door curtain shown in a partially open position.

[0026] Fig. 2 is an isolated perspective view of the sealing door of the freight container of Fig. 1.

[0027] Fig. 3 is similar to Fig. 1, but the walls of the freight container are shown in transparency.

[0028] Fig. 4 is similar to Fig. 3, but in side view and with the door panel of the sealing door shown in an open position.

[0029] Fig. 5 is similar to Fig. 4, but with the door panel of the sealing door shown in a closed position.

[0030] Fig. 6 is a detail view, marked F on Fig. 5, showing a sealing element which is compressed between the door panel and a counter-frame of the sealing door.

[0031] Fig.7 is similar to Fig.1, but with the door panel of the sealing door shown in the closed position.

[0032] Fig. 8 is a detail view, marked J on Fig. 7, showing clamping elements of the sealing door. DETAILED DESCRIPTION OF THE INVENTION

[0033] As previously stated, the invention relates to a freight container adapted to be fumigated.

[0034] In particular, the invention aims to provide a confined enclosure directly inside the container in order to store the goods and to receive the fumigant, with a view to treating the goods and the container in a simple and efficient manner.

[0035] Indeed, by limiting fumigant leakage outside the confined space, the fumigant concentration is maintained for a longer period, without having to reintroduce fumigant.

[0036] Thus, for the same quantity of fumigant, the fumigation process is more efficient than with the prior art methods described above.

[0037] Fig. 1 partially illustrates a freight container 1 according to a particular embodiment of the invention.

[0038] The container 1 comprises, in a known manner, a frame 2 and a plurality of walls mounted on the frame 2 and defining an internal volume 3. The frame 2 includes a front frame 4, a rear frame (not shown) and longitudinal members Lower 5 and upper 6 members, here four in number, connect the front frame 4 to the rear frame. The front frame 4 has a generally square shape; each of the lower and upper longitudinal members 5 and 6 connects the front 4 and rear frames at a respective corner. Other shapes can, of course, be considered for the front and rear frames.

[0039] A lower wall 7 extends between the lower stringers 5, and an upper wall 8, opposite the lower wall 7, extends between the upper stringers 6. A floor, for example made of wooden planks, covers at least partially the lower wall 7 in the interior volume 3 of the container 1. Two opposing side walls 9 each extend between a respective lower stringer 5 and upper stringer 6. A front wall 10 extends into the front frame 4, and a rear wall (not shown), opposite the front wall 10, extends into the rear frame.

[0040] A first access opening 12 is provided in the front wall 10, giving access to the interior volume 3 of the container 1. The container 1 further includes an access door 13 to open or close the access opening 12, and thus allow or prohibit access to the interior volume 3. In the container 1 shown, the access door 13 has two leaves which are hinged to the front frame 4 by means of hinges and which open outwards from the container 1. The access door 13 is provided with a locking mechanism which is known to those skilled in the art and will therefore not be described in further detail here.

[0041] A sealed fumigation chamber 15, designed to prevent the circulation of gas present inside the fumigation chamber 15 to the outside of the fumigation chamber 15, is defined within the internal volume of the container 1. The fumigation chamber 15 is defined by the lower wall 7, the upper wall 8, the side walls 9, and the lower wall 7. As the junction between certain walls, or the walls themselves, may not be perfectly airtight, potential openings that could cause fumigant leaks are sealed, for example, from inside the container 1.

[0042] In the embodiment shown, the container 1 further comprises nozzles 17 for injecting fumigant into the fumigation chamber 15. These nozzles 17 may be arranged on one or more walls of the container 1, for example, on at least one of the side walls 9. Depending on the fumigant used, the container 1 may, however, be without nozzles 17. Indeed, some fumigants, such as phosphine (PH3), are introduced in solid form into the fumigation chamber 15 and are transformed into a gas under the influence of various factors, such as humidity. Conversely, nozzles 17 are used when the fumigant is directly in gaseous form, such as carbon dioxide (CO2).

[0043] In the embodiment shown, the container 1 further includes a safety valve 18. Indeed, some fumigants, such as CO2, require that the pressure in the fumigation chamber 15 be higher than the external environmental pressure of the container 1, for example, atmospheric pressure. Other fumigants, such as PH3, can be used at atmospheric pressure. In this case, it is not necessary to equip the container 1 with a safety valve.

[0044] Container 1 further includes a sealing door 20 located in the internal volume 3. The sealing door 20, together with the walls mentioned above, defines the airtight fumigation chamber 15. The sealing door 20 extends opposite the access door 13 of container 1. Thus, the volume of the fumigation chamber 15 varies depending on the position of the sealing door 20 within container 1. For example, the volume of the fumigation chamber 15 is approximately equal to the internal volume 3 of container 1 when the sealing door 20 is placed near the access door 13, and gradually decreases as the sealing door 20 is moved further away from the access door 13. In the example shown, the sealing door 20 is positioned close to the access door 13 to maximize the volume of the fumigation chamber 15.The sealing door 20 can, however, be positioned differently, for example for applications in which part of the internal volume of container 1 does not need to be fumigated.

[0045] We will now describe in more detail, with reference to [Fig.2], the sealing door 20 of container 1.

[0046] The sealing door 20 is provided with a subframe 21, a door curtain 22 movable relative to the subframe 21 between a closed and an open position, and a sealing element (not visible) mounted here on the subframe 21. The sealing element can also be mounted on the door curtain 22, provided that the sealing element is compressed between the door curtain 22 and the subframe 21 when the door curtain 22 is in the closed position. The compression of the sealing element prevents the circulation of gas present inside the fumigation chamber 15 to the outside of the fumigation chamber 15 via the interface between the door curtain 22 and the subframe 21.

[0047] The subframe 21 defines an opening 24, which is closed when the door curtain 22 is in the closed position. The subframe 21 comprises profiles 25 assembled to form a generally U-shaped structure. Each of the profiles 25 has a generally L-shaped cross-section, with a first flange 26 and a second flange 27 extending substantially perpendicularly from the first flange 26 towards the interior of said subframe 21. The first flange 26 extends from a front face of the second flange 27. The sealing element extends peripherally on a rear face, opposite the front face, of the second flange 27. The subframe 21 comprises in addition a threshold bar 28 connecting free ends of profiles 2 forming the overall U-shaped structure, to form a closed contour structure.

[0048] The door curtain 22 is configured to pivot around a pivot axis. The sealing door 20 can therefore be described as a tilting door. In particular, the door curtain 22 is configured so as not to protrude beyond the subframe 21 when moved between the closed and open positions. The sealing door 20 can thus also be described as non-protruding. Other opening mechanisms for the sealing door 20 can be considered, such as a hinged door, a sectional door, a roller door, a sliding door, or a folding door. However, the tilting door mechanism provides greater sealing compared to other mechanisms. For this purpose, the door curtain 22 is advantageously formed in one piece. In other words, the door curtain 22 is a single unit.There is then only one interface, between the door panel 22 and the subframe 21, where leaks could occur, which reduces the risk of such leaks occurring.

[0049] To guide the door curtain 22 during its movement between the closed and open positions, the sealing door 20 includes vertical guide rails 31 and horizontal guide rails 32. The vertical and horizontal guide rails 31 are arranged to guide the door curtain in its pivoting movement between the open and closed positions. The door curtain 22 is provided with lower guide members 34 configured to slide along the vertical guide rails 31 and upper guide members 35 configured to slide along the horizontal guide rails 32. The upper and lower guide members 34, 35 are projecting from opposite sides of the door curtain 22. These guide members 34, 35 are, for example, rollers.

[0050] In particular, each vertical guide rail 34 comprises a main portion 37 extending substantially parallel to the subframe 21 and an end portion 38, on the side of the threshold bar 28 of the subframe 21, which is brought closer to the subframe 21 relative to the main portion 37, so that when the door curtain 22 is moved from the open position to the closed position, each lower guide member 34 slides first in the main portion 37 of the vertical guide rails 31 and then in the end portion 38 in which said lower guide member 34 is brought closer to the subframe 21. This end portion 38 thus makes it possible to improve the compression of the sealing member, and therefore to improve the sealing of the fumigation chamber 15.

[0051] In the illustrated embodiment, the sealing door 20 includes a drive device 40 configured to apply a tilting force to the door curtain 22, which tilting force opposes the weight of the door curtain 22 to pull it during its movement from the closed position to the open position and to prevent it from falling during its movement from the open position to the closed position. In particular, the drive device 40 is a counterweight mechanism, here comprising two counterweights 41 arranged on either side of the door curtain 22 and connecting elements 42, for example cables, each connecting a counterweight 41 to the door curtain 22. The counterweights 41 are guided during their movement by guide rails 44. Other drive devices are, however, possible, such as a motor or springs. The door curtain 22 also includes a handle 45 to facilitate its movement by a user.

[0052] We will now describe in more detail, with reference to [Fig.3], the installation of the sealing door 20 in the container 1.

[0053] In the illustrated embodiment, the subframe 21 is securely fixed, for example by welding, bonding, or the use of a sealing gasket, to the front frame 4 of the container 1 so that the threshold bar 28 extends along the side of the lower wall 7. The opening 24 defined by the subframe 21 thus forms a second access opening. In particular, the U-shaped structure of the subframe 21 is fixed to the front frame 4 by the first flange 26 of the profiles 25, while the threshold bar 28 is fixed directly to the front frame 4. The threshold bar 28 has a general plane of extension substantially parallel to the lower wall 7 of the container 1. This facilitates, in particular, the movement of equipment for loading or unloading the goods. It should be noted, however, that the subframe 21 can be fixed at another location in the container 1, for example to the walls and / or the stringers.

[0054] In an alternative embodiment not shown, the subframe lacks the threshold bar and consists only of the U-shaped structure described above. The sealing door has an additional sealing element mounted on the door panel so that, when the door panel is in the closed position, the additional sealing element is compressed between the door panel and the bottom wall (or the flooring, if the container has one) of the container. Vehicle traffic can be further facilitated by the elimination of any additional thickness at the container frame.

[0055] The horizontal guide rails 32 are held along the upper wall 8, in a direction from the front wall 10 to the rear wall, by hangers 47 fixed to the upper wall 8 of the container 1. The hangers 47 are U-shaped, with a central cross member extending between the upper stringers 6 and two lateral arms extending on either side of the central cross member. The central cross member is fixed to each of these upper stringers, which deform relatively little under the effect of temperature compared to the walls of the container 1. The rails of horizontal guides 32 are each fixed on a respective lateral branch of the suspensions 47.

[0056] Rail supports 48 are fixed to the side walls 9 of the container 1 to hold the vertical guide rails 31 along the side walls 9 in a direction from the lower wall 7 to the upper wall 8, and with the end portion 38 which is disposed on the side of the lower wall 7 of the container 1.

[0057] The guide rails 44 are held along the side walls 9 in a direction from the lower wall 7 to the upper wall 8 by guide rail supports 49 fixed to the side walls 9.

[0058] Finally, with reference to Figures 4 to 8, we will describe the operation of container 1.

[0059] To introduce goods into the fumigation chamber 15, the access door 13 and the sealing door 20 are in their open position, as illustrated in [Fig. 4]. The sealing door 20 can be held in the open position by means of counterweights 4L. In this position, the door curtain 22 extends along the upper wall 8 and the second access opening 24 is clear. The goods can then be easily introduced into the fumigation chamber 15. Furthermore, thanks to the arrangement of the threshold bar 28 of the subframe 21, the goods can be introduced using handling equipment, which can easily enter and exit container 1.

[0060] Once the goods have been introduced into the fumigation chamber 15, the sealing door 20 is moved into its closed position, for example by grasping an edge of the door panel 22 or the handle, in preparation for fumigation. In particular, in the illustrated embodiment, the sealing door 20 is pivoted about a pivot axis substantially perpendicular to the side walls 9 of the container 1. The sealing element 23 is thus compressed between the door panel 22 and the subframe 21, helping to ensure the airtightness of the fumigation chamber 15. It should be noted that the sealing element 23 can be a sealing gasket, for example, a flat gasket.

[0061] As can be seen in [Fig. 6], the subframe 21 is provided with crush stops 51 to ensure maximum compression of the sealing element 23. In other words, the crush stops 51 prevent the door curtain 22 from approaching within a predetermined distance of the subframe 21. Beyond a certain crushing threshold, the sealing element 23 does not return to its original shape when no longer compressed and no longer provides a satisfactory seal when compressed again. The crush stops 51, by limiting the compression of the sealing element 23, therefore increase the durability of the sealing element 23. In particular, the crush stops 51 are in the form of projecting sections extending around the sealing element 23.

[0062] With reference to figures 7 and 8, the sealing door 20 has clamping members 53 to bring the door panel 22 closer to the subframe 21, in order to further compress the sealing member 23. Each clamping member 53 has a rod 54 fixed on the door panel 22 and having a threaded portion, a knurled knob 55 engaging with the threaded portion of the rod 54, and a clamping piece 56 pivotally and slidingly mounted on the rod 54 between the door panel 22 and the knurled knob 55.

[0063] To bring the door panel 22 closer to the subframe 21, the clamping piece 56 is pivoted around the rod 54 until it at least partially overlaps both the door panel 22 and the subframe 21, as shown in [Fig. 8]. The thumbwheel 55 is then turned to bring it closer to the door panel 22, thus moving the clamping piece 56 along the rod 54 until the clamping piece 56 bears against both the door panel 22 and the subframe 21, and then forces the door panel 22, via the rod 54, to move closer to the subframe 21. It is then possible, via the thumbwheel 55, to control the clamping force applied. The sealing elements 53 are distributed evenly on the edge of the door panel 22, to obtain homogeneous compression of the sealing element 23. Such clamping elements are however optional.

[0064] The fumigant can be placed in the fumigation chamber 15 before the sealing door 20 is closed or injected using the nozzles 17. It should be noted that the container is configured so that, when the pressure in the fumigation chamber is higher than the ambient pressure of the container, which can occur when the fumigant is CO2, the door panel 22 is forced against the subframe 21 by the pressure difference. Indeed, the overpressure in the fumigation chamber 15 tends to push the door panel 22 towards the subframe 21 and thus compress the sealing element more than when it is simply compressed by the weight of the door panel.

[0065] After fumigation, it is sufficient to move the door panel 22 into the open position, for example by grasping it by the handle 45, and possibly by loosening the clamping elements 53. The goods can be extracted from the fumigation chamber 15 in the same way as when they were introduced.

[0066] Thanks to the invention, the container can be switched from a cargo loading configuration to a fumigation configuration simply by moving the sealing door from its open position, into which cargo can be easily introduced, to a closed position, in which a confined space is defined to receive a fumigant with a very low risk of leakage. Conversely, the container can be switched from a fumigation configuration to an unloading configuration. merchandise, simply by moving the sealing door from its closed position to an open position in which the merchandise can be easily extracted.

[0067] In other words, integrating the sealing door into the container eliminates the need for repetitive manual operations, such as covering or sealing, each time it is used. Simply opening and closing the sealing door is all that is required. The container is therefore very easy to use. Furthermore, the design of the sealing door, with the counter-frame attached to the container, ensures a good level of airtightness, improving fumigation efficiency with a smaller quantity of fumigant, which is both economical and environmentally friendly.

Claims

Demands

1. A freight container adapted for fumigation, comprising a lower wall (7), an upper wall (8) opposite the lower wall (7), opposing side walls (9) connecting the upper wall (8) to the lower wall (7), a front wall (10) and a rear wall, opposite the front wall (10), each connecting the lower wall (7), the upper wall (8) and the side walls (9), the walls together defining an internal volume (3), the container comprising a first access opening (12) provided in the front wall (10) and at least one access door (13) for releasing or closing said first access opening (12), the container being characterized in that it further comprises a sealing door (20) disposed in the internal volume (3) of said container,said sealing door (20) being provided with a subframe (21) fixed in a hermetically sealed manner to the container and defining a second access opening (24) extending opposite the first access opening (12), a door curtain (22) mounted movable relative to the subframe (21) between a closed position in which the second access opening (24) is closed and an open position, and a sealing element (23) mounted on the subframe (21) and / or on the door curtain (22) such that, when the door curtain (22) is in the closed position, the sealing element (23) is compressed between the subframe (21) and the door curtain (22).

2. A freight container according to claim 1, characterized in that it comprises a fumigation chamber (15) in the internal volume, the fumigation chamber (15) being defined by the lower wall (7), the upper wall (8), the side walls and the rear wall, as well as by the sealing door (20) when the door curtain (22) is in the closed position; the container being configured so that, when a pressure in the fumigation chamber (15) is greater than a surrounding pressure of the container, said door curtain (22) is stressed against the counter-frame (21) under the effect of the pressure difference, thus further compressing the sealing member (23).

3. A freight container according to claim 1 or 2, characterized in that the door panel (22) of the sealing door (20) is mounted to pivot about a substantially perpendicular pivot axis to the side walls (9), said door panel (22) extending along the upper wall (8) of the container in the open position so as to fully free the second access opening (24).

4. A freight container according to any one of claims 1 to 3, characterized in that the sealing door (20) further comprises vertical guide rails (31) extending along the side walls (9) in a direction from the lower wall (7) to the upper wall (8), the door curtain (22) comprising lower guide members (34) configured to slide in the vertical guide rails (31) when the door curtain (22) is moved between the open and closed positions, each vertical guide rail (31) comprising a main portion (37) extending substantially parallel to the subframe (21) and an end portion (38), on the side of the lower wall (7), which is brought closer to the subframe (21) relative to the main portion (37), such that when the door curtain (22) is moved from the open position to the closed position,Each lower guide member (34) slides first in the main portion (37) of the vertical guide rails (31) and then in the end portion (38) in which said lower guide member (34) is brought closer to the counter-frame (21).

5. Freight container according to any one of claims 1 to 4, characterized in that the sealing door (20) further comprises a drive device (40) including a drive member (41), such as a counterweight or a motor, to assist the movement of the door curtain (22) between the open position and the closed position and a connecting member (42), such as a cable, to mechanically connect said drive member (41) to said door curtain (22).

6. A freight container according to any one of claims 1 to 5, characterized in that the sealing door (20) further comprises at least one clamping member (53) for bringing the door panel (22) closer to the subframe (21), said at least one clamping member (53) comprising a rod (54) fixed to the door panel (22) and having a threaded portion, a knurled knob (55) engaging with the threaded portion of said rod (54), and a clamping piece (56) pivotally and slidably mounted on said rod (54) between the door panel (22) and the knurled knob (55), said clamping piece (56) being adapted to overlap at least partially both the door curtain (22) and the subframe (21) when the door curtain (22) is in the closed position and being configured so that when the knob (55) is turned to bring it closer to the door curtain (22), the clamping piece (56) is first moved along the rod (54) until it comes into contact with both the door curtain (22) and the subframe (21), and then forces the door curtain (22), via the rod (54), to move closer to the subframe (21).

7. Freight container according to any one of claims 1 to 6, comprising a frame (4) defining said first access opening (12) and on which the access door (13) is hinged, said container being characterized in that the counter-frame (21) is fixed to said frame (4) defining the first access opening (12).

8. Freight container according to any one of claims 1 to 7, characterized in that the counter-frame (21) comprises profiles (25) assembled together so as to form an overall U-shaped structure, each of the profiles (25) having an overall L-shaped cross-section, with a first wing (26) fixed to the frame (4) of the container defining the first access opening (12) and a second wing (27) extending substantially perpendicularly from the first wing (26) into the interior of said counter-frame (21).

9. Freight container according to claim 8, characterized in that the counter-frame (21) further comprises a threshold bar (28) connecting free ends of the profiles (25) forming the overall U-shaped structure, the threshold bar (28) being fixed on the frame (4) of the container defining the first access opening (12) and having a general extension plane substantially parallel to the lower wall (7) of the container.

10. Freight container according to any one of claims 1 to 9, characterized in that the door panel (22) of the sealing door (20) is formed in one piece.