[0001] This invention relates to cargo containers and is particularly concerned with ventilated
containers which comply with I.S.O. standards for internal and external dimensions.
[0002] According to the present invention there is provided a cargo container having a wall
including at least one ventilation chamber comprising first and second chamber walls
having perforated portions, and a transverse wall which is secured and sealed to an
adjacent corrugated portion of the container wall, the overall thickness of the chamber
being not substantially greater than the thickness of the corrugated portion, the
arrangement being such that there is substantially no direct horizontal path between
the perforated portions of the outer and inner walls of the chamber. In such an arrangement,
the transverse wall provides a stiff anchorage and reinforcement for the adjacent
corrugated portion of the wall and the overall wall thickness need not appreciably
exceed that of a conventional dry-freight closed container. Accordingly the container
can carry the same volume of cargo as the conventional container.
[0003] Preferably the container wall has two ventilation chambers, one at the bottom of
the wall and the other at the top. The wall thus formed-complies with I.S.O. standards
of rigidity and the external and internal dimensions of the container also comply
with I.S.O. standards.
[0004] An embodiment of the invention will now be described by way of example with reference
to the accompanying drawings in which:-
Fig. 1 is a vertical section through an upper part of a wall of a cargo container
showing ar upper ventilation chamber located close to the top of the wall, and
Fig: 2 is a vertical section through a lower part of the wall shown in Fig. 1 showing
a lower ventilation chamber close to the bottom of the wall.
[0005] The drawings show an upper ventilation chamber 10 forming part of a side wall 6 of
a cargo container; the upper chamber 10 is attached at its upper edge to a roof 14
of the container and at its lower edge to a corrugated portion 12 of the wall. The
corrugated portion 12 of the wall is of the type used in the walls of conventional
cargo containers and extends between the upper ventilation chamber 10 and a lower
ventilation chamber 50 which is fixed to a base 8 of the container.
[0006] Referring now to Fig. 1, the upper chamber 10 is formed from a piece of sheet metal
which is bent to form an outer wall 16, a roof 18 and a floor 20. Lips 22, 24 are
formed at the edges of the roof 18 and floor 20 and carry an inner wall and baffle
plate assembly 26 which is attached to the lips by nuts and bolts such as 28.
[0007] The assembly 26 comprises an inner wall 27 of the chamber 10 and a baffle plate 34
which extends over the whole length of the wall 27 and is attached to the inner wall
27 by rivets such as 29 passing through lips 37 of flanges 36 of the baffle plate
34. The flanges 36 are drilled with ventilation holes 38 at regular intervals along
their length.
[0008] A lower portion of the outer wall 16 is perforated over its _whole length as indicated
at 30 and an upper portion of the inner wall 27 between the flanges 36 of the baffle
plate 34 is similarly perforated as indicated at 32. The perforations 30, 32 are typically
circular holes of 9.5mm.
diameter which are spaced in rows at 15mm distances between their centres, the holes
in adjacent rows being staggered.
[0009] The wall and baffle assembly 26 may be removed from the chamber 10 for cleaning and
other servicing purposes and is preferably galvanised to protect the inaccessible
inner surfaces of the wall 27 and baffle plate 34.
[0010] Drainage holes 40 are drilled through the floor'20 at intervals along its length.
The holes 40 are positioned at points where they communicate with the exterior of
the container, that is, above troughs of the corrugated portion 12 of the wall 6 which
are open to the exterior.
[0011] Fig. 2 shows the lower ventilation chamber 50 formed in a lower part of the side
wall 6 of the cargo container. A piece of sheet metal is bent to form a side-rail
56 of the base 8 of the container, a floor 57 of the lower chamber 50, an outer wall
54 and a roof 60. The upper surface of the roof 60 is welded to the corrugated portion
12 of the side wall 6 of the container. A downwardly-depending lip 62 is formed along
the inner edge of the roof 60 and an inner wall 64, also bent from sheet metal, is
secured to the lip 62 by rivets such as 66.
[0012] . A horizontal notch 55 extends the whole length of the outer wall 54 and contributes
to the stiffness of the lower chamber 50.
[0013] The inner wall 64 is formed into a flange 68 along its lower edge and is secured
by rivets such as 70 to a flanged rail 72 which is welded to the floor 57.
[0014] The inner wall 64 is perforated close to its upper edge as indicated at 78. The perforations
78 are of similar size and spacing to the perforations 30, 32 of the upper ventilation
chamber 10 shown in Fig.l. Holes 76 are drilled in the floor 57 of the chamber 50
and communicate with the exterior of the container. A series of holes 80 in the roof
60 communicate with the interior of the container and allow condensation from troughs
of the corrugated portion 12 of the wall 6 which are open to the interior of the container
to drain into the second chamber 50.
[0015] The interior of the container is ventilated as follows. Relatively cold air enters
the lower ventilation chamber 50 through the holes 76, passes upwardly through the
chamber 50 and into the interior of the container through the perforations 78. Hotter,
more humid air from the interior escapes through the perforations 32, upwardly or
downwardly around the baffle plate 34 through the holes 38 and out of the upper chamber
10 through the perforations 30.
[0016] Entry of rain or sea-spray to the container is prevented in the case of the upper
chamber 10 by the baffle plate 34 and in the case of the lower chamber 50 by the perforations
78 in the inner wall 64 being located higher than the holes 76 in the floor 57 and
by the perforations 76, 78 being spaced vertically by portions of the walls 54, 64
which have no perforations.
[0017] Any water which enters either chamber can drain away to the exterior of the chamber
through the holes 40, 76. The lower chamber 50 also collects condensation from the
interior surfaces of the container through the holes 80 and this condensation can
drain away through the holes 76.
[0018] It will be noted that in the container described above the ventilation chambers do
not increase substantially the external dimensions of the container nor is the internal
volume substantially reduced. Thus, the container is able to comply with I.S.O.standards
for dry cargo containers as regards both internal and external dimensions.
[0019] The stiffness of the ventilation chambers and their junctions with the remainder
of the sidewalls is also sufficient to not reduce the overall stiffness of the corrugated
walls and thus the container described above also meets I.S.O.standards in this respect.
[0020] The container described above is particularly suitable for materials such as coffee
beans which are loaded in a moist state under hot, humid conditions. The ventilation
chambers allow air to circulate through the interior of the container to prevent deterioration
of the cargo.
1. A cargo container having a wall including at least one ventilation chamber comprising
first and second chamber walls having perforated portions, and a transverse wall which
is secured and sealed to an adjacent corrugated portion of the container wall, the
overall thickness of the chamber being not substantially greater than the thickness
of the corrugated portion, the arrangement being such that there is substantially
no direct horizontal path between the perforated portions of the first and and second
walls of the chamber.
2. A container according to claim 1 including a said ventilation chamber in which
the first and second chamber walls are inner and outer walls, the perforated portions
of which are offset.
3. A container according to claim 2 including a said ventilation chamber having a
baffle plate spaced from the outer and inner walls of the chamber,
4. A container according to claim 3 wherein both the top and bottom edges of the baffle
are spaced from top and bottom walls of the ventilation chamber.
5. A container according any of the preceding claims wherein the ventilation chamber
is formed in a hollow rail extending along the length of the wall.
6. A container according to any preceding claim in which the said ventilation chamber
is a lowermost portion of the said container wall, the first chamber wall being an
inner wall and the second chamber wall being a bottom wall.
7. A container according to any preceding claim in which a said ventilation chamber
has drainage holes communicating the interior of the chamber with the exterior of
the container.
8. A container according to claim 7 in which a said ventilation chamber is not an
uppermost portion of the said container wall-and has holes, for drainage of condensation,
communicating the interior of the container with the chamber.
9. A container according to any preceding claim having a first said ventilation chamber
forming an uppermost portion of the said wall of the container, the said transverse
wall being a floor and the said first and second walls being inner and outer walls
of the first chamber, a second said ventilation chamber forming a lowermost portion
of the said wall of the chamber, the said transverse wall being a top wall and the
said first and second walls being respectively inner and bottom walls of the second
chamber, and the said corrugated portion being a portion of the said wall extending
between the first and second chambers.
10. A container according to any preceding claim in which an outer wall of a said
chamber is strengthened by an inwardly- directed notch portion extending substantially
horzontally.