GB2336357A

GB2336357A - Wide body tank container

Info

Publication number: GB2336357A
Application number: GB9908418A
Authority: GB
Inventors: Michael Himbury
Original assignee: UNIVERSAL BULK HANDLING LIMITE
Current assignee: UNIVERSAL BULK HANDLING LIMITE
Priority date: 1998-04-14
Filing date: 1999-04-14
Publication date: 1999-10-20
Also published as: GB9908418D0; GB9807753D0

Abstract

A tank container comprises a cylindrical tank mounted within a framework having corner fittings 3 defining a notional cuboid whose ends have a width less than the maximum width of the tank. Two side beams 21 extend between the ends of the container, the beams having outer surfaces spaced apart by at least the maximum width of the tank and being vertically displaced from the maximum width of the tank. Resiliently deformable buffer members 27 are located between the beams 21 and the tank.

Description

1 2336357 Title: Wide Body Tank Container The present invention relates to

a wide bodied tank container.

Tank containers comprise a tank, usually cylindrical, and a frame providing eight corner fittings whose position complies with the standards for ISO freight containers which are commonly of cuboidal shape and have a width of 8 ft (243 8 nun) and a length of 20, 3 0 or 40 ft (6096, 9144 or 12192 mm). When such freight containers are transported at sea they are commonly located in a hold which is divided by guides into a number of cells each of a width sufficient to hold one container. For orting containers of the above sizes the guides are fixed with a lateral spacing of a little over 8 ft (2438 min) so that the ends of a container 8 ft wide can just be fitted between them.

It is sometimes desired to cany metric pallets in such containers, these pallets having a standard size of 1.2 metres by 1 metre. In order to accommodate two pallets side by side with their major dimensions extending across the container, the latter must have an internal width of 2.4 metres and this is not possible when the overall width of the container is 8 ft (2438 mm).

This has led to the development of the so called "wide bodied container" as described in European Patent Publication 0206542. In order to permit such a wide bodied container to fit within the standard cells of a ship hold, the sides which define the lateral extremities of the container and extend between the ends of the container have exterior surfaces which are spaced apart by a greater distance along their middle portions than at their end portions which are joined to the ends of the container, whereby the overall width of the container is less at the end portions than at the middle portion. By this means the end portions place the corner fittings m 2 the same positions as they would for a normal width container whilst the portion therebetween is wider, hence the term wide bodied container. It will be appreciated that the increase in width is only small and does not prevent containers from being disposed side by side in the vessel within the cells which are defined by end frames. The consequence of this is that increased carg go capacity is achieved. With the standard width of containers there would be a gap between adjacent containers equal to the width of the cell framework.

The adoption of the wide bodied enclosed freight container has given rise to the realisation that an equivalent wide bodied tank container Le. one which has a tank width which is greater than the width of the end frames, could be employed. One advantage of being able to offer a wide bodied tank container is the ability to offer a better insulated tank which will have the same capacity as of a relatively poorly insulated tank c.... a 26,000 litre tank. A poorly insulated tank of this capacity will just fit within the envelope defined by the standard corner fittings. However, introduction of a wide bodied tank container does create potential difficulties when it comes to liftincy of the container.

Traditionally freight containers are lifted from overhead using a lifting frame which engages with each of the four upper corner fittings. A side lifting method is also used which t> c W has two en-aaers which are adapted to engage with the two uppermost corner fittings of one w side and which has a lower abutment surface with which a side of a container will abut during lifting. The abutments are designed to contact the sides of the container in the region of the 1 0 lower corner fittings but the design of the lifting device is such that with a wide bodied c - container the side of the container where it projects beyond the width of the side frames will 3 come into contact with the lifting mechanism. This would impart considerable load to the container in a position which is not ideally structured to receive that load. In the case of a tank container this could be particularly dangerous hence in designing a wide bodied tank container it is necessary to take into consideration the desirability of using a side lifting method and to provide a means for resisting such a load.

One solution would be to provide a tank container of the type comprising a fluid receiving tank mounted with respect to a framework defining eight corner fittings of the tank container and wherein the corner fittings are positioned to define a notional cuboid of which two opposite ends have a width which is less than the maximum width of the tank, with a pair of opposite side beams which extend between the ends of the container and in which the exterior surfaces of the pair of opposite side beams are spaced apart by a distance corresponding to at least the maximum width of the tank and are located at a position displaced vertically from the maximum width of the tank, and to construct the side beams sufficiently robustly to resist bending when subject to the side loading at a position along its length, especially at the weakest point, i.e. midway between any unsupported span. This solution has the disadvantage of introducing a considerable weight penalty. Where the tank container is provided with longitudinally spaced stifIening rings, the opposite side beams could be connected to the stiffening rings to provide additional bracing at axially spaced locations. This still leaves the beam vulnerable to bending where it is unsupported unless constructed sufficiently robustly, as well as having the potential disadvantage of complicating the design of the tank container and inevitable increasing the cost thereof.

4 The present invention aims to provide a solution which avoids the above mentioned disadvantages.

Accordingly the present invention provides a tank container comprising a fluid receiving tank mounted with respect to a framework defining eight corner fittings of the tank container and wherein the corner fittings are positioned to define a notional cuboid of which two opposite ends have a width which is less than the maximum width of the tank, the framework further comprising a pair of opposite side beams which extend between the ends of the container and in which the exterior surfaces of the pair of opposite side beams are spaced apart by a distance corresponding to at least the maximum width of the tank and are located at a position displaced vertically from the maximum width of the tank, and wherein each of the opposite side beams has at least one portion which is spaced from an adjacent surface of the tank and wherein a resiliently deformable member is interposed between said at least one portion and the adjacent surface of the tank to act as a resilient buffer.

In the event of the side beam defonning in a side lifting situation or as a result of other such side i acts, the resiliently deformable member distributes the load into a larger area of imp 1 the tank thereby avoiding permanent deformation of the tank.

The resiliently deformable member may be provided along the entire length of the side beam when it is adjacent the tank or only along a part of said length. Where only along part of said length it will be disposed over the part where the beam deformation is likely to be greatest and likeIv to cause tank dama.

ge.

In a preferred construction the framework comprises a pair of opposite end frames and the pair of opposite side beams connect with the opposite end frames and extend therebetween. The exterior surfaces of the pair of opposite side beams are spaced apart by a greater distance along their middle portions than at their end portions which are joined to the end frames of the container. The pair of opposite side be= may connect with two longitudinally spaced stiffening rings secured to the tank and in such a case the resiliently deformable material is interposed between the beam and tank over all or a substantial part of the length of the beam spanning the stiffening rings.

The preferred material for the buffer comprises a high density foam plastic material.

Other resilient materials may be employed. More preferably the foam plastics material is encased within an impermeable cover which is conveniently formed from a flexible plastics material, such as polypropylene. More preferably still the buffer has a surface area in contact with the periphery of the tank which is er than the area of the adjacent side of the side beam.

The present invention will now be described further by way of example only with reference to the accompanying drawings in Which:- Fieure 1 is a side view of a tank container embodying the present invention; Figure 2 is an end view of the tank container of Figure 1 to an enlarged scale; and Figure 3 is a part sectional view on AA of Figure 1 to an enlarged scale.

Referrina,, to the drawings, a-tank container accordmig to the present invention comprises a cylindrical fluid receivmg yessel 1 which is mounted with respect to a framework which defines eight corner fittings 3 (four to each end). The shell of the vessel is referenced 4 1:1 6 in Figure 2. The position of the four corner fittings is such as to define a notional cuboid havina a width, height and length corresponding to the standards adopted for freight containers. The illustrated embodiment of tank container comprises a so called beam tank in which the tank itself forms part of the structure of the container. The invention is not limited in its application to a so called "beam tank" and can be applied to other designs of tank container.

Usually the tank containers will have the aforementioned eight corner fittings. In the illustrated embodiment the four corner fittings to each end are connected to the cylindrical tank by pairs of upper and lower inclined side arms 5, which contact with the container tank at their inner ends 11, 13. Further lower support arms are provided as shown at 9 and a set of securing arms 10 are provided at each end as seen in the end view of Figure 3, but are not visible from the side view. The four corner fittings, 3 to each end, are connected by upright members 15 and horizontal members 17 to form a rectangular end frame to each of the opposite ends of the tank container. The overall width of the end frame is 2438 mm.

The horizontal centre line of the tank is shown by chain dotted line 19 and corresponds to the maximum width of the tank. If the tank is to fit in the hold of a ship intended for transporting standard containers then the width of the container can be slightly greater than the width of the ends of the container as defined by the corner fittings and interconnecting frame members. The increase in overall diameter of the container may be 60 mm or less but this will have the effect of either increasing the potential volume by more than 1M3 for a 20 ft container in the case of an uninsulated tank, or permitting insulation to be fitted to such a container m,hilst still increasing the capacity.

7 In order to avoid the tank being contacted directly using a side lifting apparatus, the opposite sides of the tank are provided with a longitudinally extending side beam 21, conveniently made by a hollow section steel, which runs parallel to the axis of the tank container for the majority of its length before being flared inwardly at 23 towards the opposite ends thereof to mate with the uprights 15 of the end frames. The overall width as measured at the side beams is 2500 mm in the illustrated embodiment. The greatest width of the container tank will correspond to the width between the side beams. In the illustrated embodiment a beam is provided to each side of the container tank and disposed downwardly of the maximum diameter of the tank. It is located at a position displaced vertically offset from the maximum diameter of the tank. Sometimes it may be desirable to provide one at a location above the horizontal centre Iffle. Sometimes it maybe advantageous to provide one above and one below the horizontal centre line. According to the invention a resilient buffer/fender is interposed between an inside surface 21 a of the side beam 21 and the adjacent external surface of the tank shell 4. The buffer 25 may extend along the entire length of the tank up to the commencement of the domed end portions as defined by line 25, but more preferably it only extends substantially between stiffening rings X & Y. The buffer comprises a core of high density foam plastics material 27 which is moulded with a arcuate surface which closely conforms with the arcuate surface of the tank cladding and is covered by a water impermeable flexible material 29, which is one embodiment is a polypropylene plastics, and which is conveniently attached to the surface of the container. In the illustrated embodiment there is a small clearance between the fender and the inside surface 21 a of the side beam 21. If the side beam 8 21 is deflected such that it contacts the buffer 27 the nature of the material is such that it transmits the load uniformly into the side of the container. In the illustrated embodiment the outer periphery of the tank container is covered by insulating material 35 and a non-stressed skin 36 overlies the insulation material. In one embodiment this skin comprises a glass reinforced plastics cladding which goes all the way round the tank. 33 is a reinforcing hoop. The insulation 35 and GRP cladding is omitted in the side view of Figure 1.

Where the tank is provided with longitudinally spaced stiffening rings X, Y, then, optionally, the side beams may be coupled to the stiffening rings. Conveniently the opposite lateral sides of each of the stiffening rings X, Y carries a saddle 30. In effect this constitutes a width wise extension of the stiffening ring which provides a lateral abutment surface which provides additional.protection to the tank. The width between the opposite abutment surfaces tapers inwardly from a point of maximum width immediately adjacent the side beams 21 to the narrowest point upwardly of the maximum diameter of the tank.

In many designs, the outer surface of the shell 4 has a so called "steam coil" applied to it. These comprise a series of channels which run alone, the surface of the shell and which are spaced apart circumferentially. The ends are connected to a manifold to permit steam or some other fluid to be circulated there through.

In the illustrated embodiment, one of these channels is shown at 3 1 and is positioned so as to be in substantial horizontal alignment with the side beam. In this position it can function to reinforce the side of the tank and will act to aid load distribution into the tank from the buffer.

9

Claims

1. A tank container comprising a fluid receiving tank mounted with respect to a framework defining eight corner fittings of the tank container and wheremi the corner fittings are positioned to define a notional cuboid of which two opposite ends have a width which is less than the maximum width of the tank, the framework further comprising a pair of opposite side beams which extend between the ends of the container and in which the exterior surfaces of the pair of opposite side beams are spaced apart by a distance corresponding to at least the maximum width of the tank and are located at a position displaced vertically from the maximum width of the tank, and wherein each of the opposite side beams has at least one portion which is spaced from an adjacent surface of the tank and wherein a resiliently deformable member is interposed between said at least one portion and the adjacent surface of the tank to act as a resilient buffer.

A tank container as claimed in claim 1 in which the resiliently deformable member provided along at least part of the 1 of the side beam when it is adjacent the tank 3. A tank container as claimed in claim 2 in which the resiliently deformable member is disposed over the part of the side beam where the beam deformation is Rely to be greatest and likely to cause tank damage.

4. A tank container as claimed in claim 1 in which the resiliently deformable member is ided along the entire length of the side beam where it is adjacent the tank. proyl 5. A tank container as claimed in any one of claims 1 to 4 in which the framework comprises a pair of opposite end frames and the of opposite side beams connect with the opposite end frames and extend therebetween.

A tank container as claimed in any one of claims 1 to 5 in which the exterior surfaces of the pair of opposite side beams are spaced apart by a greater distance alone, their middle portions than at their end portions which are joined to the end frames of the container.

A tank container as claimed in any one of claims 1 to 6 in which the pair of opposite side beams connect with two longitudinally spaced stiffening rings secured to the tank and the resiliently deformable material is interposed between the beam and tank over all or a substantial part of the length of the beam spanning the stiffening rings.

8. A tank container as claimed in any one of the preceding claims in which the buffer comprises a high-density foam plastic material.

9. A tank container as claimed in claim 8 'm which the foam plastic material is encased within an impermeable cover.

10. A tank container as claimed in claim 9 in which the impermeable cover is formed from a flexible plastics material.

11. A tank container as claimed in any one of the preceding claims in which the buffer surface area in contact with the periphery of the tank which is greater than the area of the adjacent side of the side beam.

12. A tank container constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying dramngs.