[0001] The invention relates to a container comprising a wall provided with a profile in
order to prevent said wall from bending outwards. The invention relates in particular
to a container for transport and storage of liquids, preferably liquid chemicals.
[0002] Such a container is widely known. In practice the known container, which is generally
made of polyethylene (PE), polypropylene (PP) or polyamide (PA), is often used for
transport and storage of hazardous materials. The term hazardous materials as used
herein is understood to mean materials which are legally designated as such in a particular
country. The known container are usually subdivided in roughly two classes: durable
containers having a wall thickness of about 8 mm, as well as containers to be used
"once only" (up to five times, for example). It will be apparent that containers of
the latter category must be made as cheap as possible, whereby first of all a saving
on the cost of materials must be considered.
[0003] One drawback of the known container is the fact that it has become apparent in practice
that the above saving on the cost of materials is hardly possible, if at all, since
a container having a (considerably) smaller wall thickness than the usual 8 mm exhibits
undesirable deformations in use. Said deformations are caused by a lateral pressure
exerted by a chemical liquid which is present in the container, which causes ribs
in the profile of the container wall to move apart.
[0004] The object of the invention is to obviate the drawbacks of the prior art, thus making
it possible to provide thin-walled plastic containers having a sufficient wall strength,
and in order to accomplish that objective, a container of the kind referred to in
the introduction is characterized in that the profile is at least partially closed.
Preferably, the profile is thereby formed by at least one, at least substantially
U-shaped wall part extending inwards from the wall at the location of two opposed
wall edges, seen in horizontal cross-sectional view of the wall, which wall part is
closed in at least one place by connection of the respective vertically extending
wall edges. This connection forms a "bridge", as it were, between ribs present in
the profile, so that the aforesaid lateral deformations caused by the liquid pressure
are prevented from occurring. This makes it possible to manufacture thin-walled containers
which are suitable for use "once only" at a considerably lower cost price than the
usual, durable containers.
[0005] In one preferred embodiment of a container according to the invention, said wall
part is closed in at least two places, preferably in at least three places. Preferably,
the wall part is entirely closed, at least substantially so. The advantage of this
is that the container, depending on what is required in practice, possesses increased
wall strength, which makes it possible to make the wall considerably thinner. Preferably,
the wall has a thickness of 2 - 6 mm, in particular 4 - 5 mm.
[0006] In another preferred embodiment of a container according to the invention, the connection
between the respective wall edges is made in one piece with the wall. It is preferred
to manufacture the container according to the so-called "kiss-on/kiss-off" principle
by means of rotational moulding.
[0007] In another preferred embodiment of a container according to the invention, said wall
part continues over the upper side and/or the bottom side of the container.
[0008] In another preferred embodiment of a container according to the invention, several
wall parts are arranged in evenly spaced-apart relationship over the circumference
of the wall. The wall is thus uniformly strengthened over its entire circumference.
[0009] In another preferred embodiment of a container according to the invention, said container
is made of a plastic, in particular PE, PP or PA. Preferably, a rotational moulding
process is used thereby.
[0010] The invention furthermore relates to a method for manufacturing a container comprising
a wall provided with a profile in order to prevent the wall from bending outwards,
characterized in that, seen in horizontal cross-sectional view of the wall, said profile
is formed by at least one, at least substantially U-shaped wall part extending inwards
from the wall at the location of two opposed wall edges, which wall part is closed
in at least one place by connecting the respective vertically extending wall edges.
[0011] The invention will now be explained with respect to figures illustrated in a drawing
of a preferred embodiment of the invention, wherein:
- Figure 1 is a schematic, perspective view of a container according to the invention;
- Figure 2 is a schematic plan view of the container of Figure 1; and
- Figure 3 is a schematic, horizontal cross-sectional view of Part of the container
of Figure 1.
[0012] Figure 1 shows an at least substantially cubic (liquid) container 1, in particular
for liquid chemicals. The container 1, which is provided with a filer cap 2 and a
draw-off cock 3, is placed on a pallet 4 to facilitate transport and storage.
[0013] Container 1 is provided with a profile which is evenly distributed over the circumference
of the wall 5. Seen in horizontal cross-sectional view of wall 5, said profile is
made up of several at least substantially U-shaped wall parts 7, which each extend
inwards from wall 5 at the location of two opposed wall edges 6 (Figures 2 and 3).
In accordance with the invention, said wall parts 7 are closed in vertical direction
over a particular distance by bridges 8, which form a connection between the respective
wall edges 6. Wall parts 7 and bridges 8 jointly form O-shaped cylinders 9, as it
were.
[0014] Bridges 8 prevent stiffening ribs 10 of the profile of the container 1 from moving
out when container 1 is being filled with a chemical liquid, which would lead to undesirable
deformation.
[0015] In Figures 2 and 3, those parts that correspond with parts which are shown in Figure
1 are indicated by the same numerals.
1. A container comprising a wall provided with a profile in order to prevent said wall
from bending outwards, characterized in that said profile is at least partially closed.
2. A container according to claim 1, wherein said profile is formed by at least one,
at least substantially U-shaped wall Part extending inwards from the wall at the location
of two opposed wall edges, seen in horizontal cross-sectional view of the wall, which
wall part is closed in at least one place by connection of the respective vertically
extending wall edges.
3. A container according to claim 2, wherein said wall part is closed in at least two
places, preferably in at least three places.
4. A container according to claim 2 or 3, wherein said wall part is entirely closed,
at least substantially so.
5. A container according to claim 2, 3 or 4, wherein the connection between the respective
wall edges is made in one piece with the wall.
6. A container according to any one of the preceding claims 2 - 5, wherein said wall
part continues over the upper side and/or the bottom side of the container.
7. A container according to any one of the preceding claims 2 - 6, wherein several wall
parts are arranged in evenly spaced-apart relationship over the circumference of the
wall.
8. A container according to any one of the preceding claims 2 - 7, wherein said container
is made of a plastic, in particular PE, PP or PA.
9. A container according to claim 8, wherein said container has been manufactured by
means of a rotational moulding process.
10. A method for manufacturing a container comprising a wall provided with a profile in
order to prevent the wall from bending outwards, characterized in that, seen in horizontal cross-sectional view of the wall, said profile is formed by at
least one, at least substantially U-shaped wall part extending inwards from the wall
at the location of two opposed wall edges, which wall part is closed in at least one
place by connecting the respective vertically extending wall edges.