The present invention relates to a liquid tank container according to the preamble of Claim 1. In addition, the invention relates to a method for producing such a liquid tank container.

In freight transport, use is often made of liquid tank containers for the transport of liquids, for example semi-fmished products for the chemical industry or food industry.

This freight transport, also referred to as intermodal freight transport, is often international, with a liquid container being transported both via the road and via the waterways. The liquid tank container is transferred from a lorry or train to a ship and vice versa. For this reason, such a liquid tank container is configured to have the standard dimensions for a sea container for bulk goods, so that transfer and transportation of liquids is facilitated.

The liquid tank container comprises a frame in which a liquid tank is placed. In this case, the frame has the standard dimensions of the rectangular sea container and is configured such that it can be placed on a carrier for the frame. Said carrier may be both a top side of another frame and a suitable transport chassis of a lorry or ship.

In the prior art, the liquid tank of the liquid tank container consists of a steel vessel. The steel ensures that the structure of the liquid tank is sufficiently strong. For many types of liquid, it is a requirement that the liquid which is being transported does not react with the wall of the metal liquid tank during transportation. It is for this reason that the liquid tank is often made from stainless steel or the steel wall of the liquid tank is provided with a liner. In many cases, the outer side of the tank is also provided with a covering and/or insulating outer sleeve, for example a coating or a metal shell.

The current liquid tank containers therefore have the drawback that their weight is relatively high, due to the weight of the metal liquid tank and any outer sleeve which may be present. This results in relatively high energy consumption during transportation. In addition, a relatively heavy tank can carry less useful load, that is to say can transport less liquid due to the legal limit for the maximum total weight of a loaded liquid tank container.

In addition, stainless steel is relatively expensive. If, in addition, a liner is being used, this will lead to a further increase in the construction and maintenance costs.

It is an object of the present invention to reduce and/or eliminate one or more of the prior-art problems.

To this end, the invention provides a liquid tank container for use in container goods transport, comprising an elongate or substantially cylindrical liquid tank and a frame,
wherein the liquid tank comprises a central section and two end covers, wherein in each case one end cover closes off an end of the central section;
and wherein the liquid tank is placed in the frame and the frame is configured to be placed on a carrier for the frame,
wherein the liquid tank is made from composite material and the frame is provided with fastening means, wherein the fastening means are mounted on a wall section of the composite liquid tank in such a manner that the composite liquid tank is anchored in the frame, and
wherein the fastening means comprise a retaining piece which is connected to the frame and which is provided with an opening with a contact wall inside which a surface part of the wall of the composite liquid tank is held, and wherein the liquid tank made from composite material is self-supporting, and the frame only consists of subframes formed by the end supports, without horizontal support beams which connect the end supports to one another.
By making use of said fastening means, a stable fastening of the tank inside the frame is achieved in an advantageous manner.

Due to the smaller weight of the composite tank compared to a steel tank, the transport costs will be reduced. In addition, composite materials are less susceptible to corrosion, thus reducing the risk of the tank wall reacting with the liquid to be transported. As a result thereof, the maintenance of the tank can also be reduced in an advantageous manner.

Furthermore, the properties of composite are superior to those of the prior-art materials for keeping products at the correct temperature, resulting in savings on additional insulation weight and insulation costs.

In an embodiment, the fastening means form a connection between the frame and the tank wall by means of adhesive joint(s).

Furthermore, the invention relates to a liquid tank container as described above, wherein an adhesive joint is present between the contact wall of the retaining piece facing the wall of the composite liquid tank and this wall.

Furthermore, the invention relates to a liquid tank container as described above, wherein the end supports are situated at or close to the end covers of the composite liquid tank; the fastening means are connected to the end supports, and the fastening means retain the composite liquid tank in the frame.

The invention also relates to a liquid tank container as described above, wherein, for each end support, the fastening means comprise a retaining piece which is connected to the end support and the retaining piece is provided with the opening with the contact wall inside which in each case the end of the central section of the composite liquid tank is held by means of the adhesive joint.

In addition, the invention relates to a liquid tank container as described above, wherein the end support in each case comprises a number of brackets which mutually enclose an end of the central section of the composite liquid tank; the brackets comprise a pair of bearing arms, each of which is connected to a corner of the end support and extends from the respective corner to the body axis of the composite liquid tank, and each bearing arm has a curvature which substantially corresponds to the curvature of the end cover of the composite liquid tank in such a manner that the wall of the end cover of the liquid tank bears against the bearing arm.

In yet a further embodiment, the invention relates to a liquid tank container as described above, wherein the end support furthermore comprises an upper bracket which is provided with a profile which bears against a top side of the composite liquid tank.

Furthermore, the invention relates to a liquid tank container as described above, wherein one or more of the brackets comprise a contact surface for an adhesive joint with the wall of the composite liquid tank.

The invention furthermore relates to a liquid tank container as described above, wherein the fastening means is provided with one or more adhesive surfaces which are in contact with the wall of the composite liquid tank in order to achieve a connection between the end support and the liquid tank.

The invention relates to a liquid tank container as described above, wherein the liquid tank container is of the swap body type.

In an embodiment, the invention relates to a liquid tank container as described above, wherein the liquid tank container is of the beam tank type, wherein the end supports at each corner of their frame comprise a beam which is not at right angles to the end support and extends towards the other end support and wherein an end of the beam serves as a fastening means to, and is connected to, the wall of the liquid tank.

In an embodiment, the invention relates to a method for producing a liquid tank container for use in container goods transport, which container comprises an elongate or substantially cylindrical liquid tank and a frame,
wherein the liquid tank comprises a central section and two end covers, wherein in each case an end cover closes off an end of the central section;
wherein the method comprises placing the liquid tank in the frame and the frame is configured to be placed on a carrier for the frame, wherein the liquid tank is made from composite material and the frame is provided with fastening means in each case comprising a retaining piece which is connected to the frame and which is provided with an opening with a contact wall, wherein the method comprises: bringing the wall of the composite liquid tank inside the opening with the contact wall, fitting the contact wall against a wall of the composite liquid tank and holding a surface part of the wall of the composite liquid tank inside the contact wall, wherein the liquid tank made from composite material is self-supporting, and the frame only consists of subframes formed by the end supports, without horizontal support beams which connect the end supports to each other.

Furthermore, the invention relates to a method as described above, wherein the method comprises: providing an adhesive joint between the contact wall and the surface part of the wall of the composite liquid tank.

Further embodiments of the liquid tank container according to the present invention are described in the subclaims.

The invention will be explained below in more detail with reference to a number of drawings, in which some exemplary embodiments are shown. The drawings are only intended for illustrative purposes and not as a limitation of the inventive idea which is defined in the attached claims.

The drawings show:

• Figures 1a, 1b, 1c respectively a show a side view, an end view and a cross section of a first embodiment of a liquid tank container according to the invention;
• Figures 2a, 2b respectively show a side view and an end view of a second embodiment of a liquid tank container according to the invention;
• Figures 3a, 3b respectively show a side view and an end view of a third embodiment of a liquid tank container according to the invention;
• Figures 4a, 4b respectively show a side view and an end view of a fourth embodiment of a liquid tank container according to the invention.

In the following figures, identical reference numerals in each case refer to corresponding parts in these figures.

According to the invention, the liquid tank container 1 comprises a liquid tank and a frame, wherein the liquid tank is made from composite material. The tank wall is made from a fibre-reinforced plastic consisting of a plastic matrix which incorporates a fibre material. If desired, the tank wall also comprises other (plastic) layers on top of the layer of fibre-reinforced plastic.

The process of producing the fibre-reinforced plastic from the various components, the plastic and the fibre material, is known per se to a person skilled in the art. Processes for making the tank wall from the fibre-reinforced plastic are also known to the person skilled in the art.

The frame consists of a metal (often steel) construction which serves to support the liquid tank during transport and transfer.

Figures 1a and 1b respectively show a side view and an end view of a first embodiment of a liquid tank container 1 according to the invention.

In the embodiment from Figure 1, the composite liquid tank container is cylindrical and of the swap body type, the length of the liquid tank being greater than the length of the supporting frame.

In an embodiment, the liquid tank 5 comprises one or more manholes 5a, 5b and at least one discharge connection 5c. The liquid tank 5 is composed of a substantially cylindrical central part 5d which is closed off at each end of the cylinder by an end cover 5e.

Internally, the liquid tank 5 may be provided with a number of swash partitions (not shown) for limiting the movement of liquid in the tank during transportation. In an embodiment, these partitions are made from composite material and are glued to the wall of the liquid tank.

The liquid tank 5 is supported by the frame which comprises upright end supports 6, 8 near each of the ends of the liquid tank 5. The two upright end supports 6, 8 are connected to each other by horizontal support beams (or horizontal supporting frame) 7 which extend underneath the liquid tank on either side of the liquid tank.

In an optional embodiment, a number of bottom supports 9 are provided on the horizontal support beams between the upright end supports 6, 8 on which the underside of the liquid tank can rest.

The upright end supports are each configured as a frame of horizontal and vertical girders 10a, 10b which are connected to each other in order to form the frame.

Each of the end supports furthermore comprises a fastening means in the form of a retaining piece 11 which is provided with a contact wall which forms an opening inside which the circumference of the cylinder of the liquid tank is held. The shape of the opening is such that the opening in the retaining piece 11 fits the circumference of the liquid tank 5. In addition, the material of the retaining piece around the opening has a certain height in the direction parallel to the longitudinal axis/cylinder axis of the liquid tank, so that the contact wall is a surface within the opening in the retaining piece for forming a contact surface with the wall of the liquid tank.

Figure 1c shows a cross section of the connection between the retaining piece 11 and the wall of the liquid tank 5 at the location of a horizontal girder 10a of the end support 10. The retaining piece 11 has some clearance with respect to the cross section of the liquid tank 5, so that the liquid tank 5 and the retaining piece 11 can be moved with respect to one another along the longitudinal axis of the liquid tank during fitting.

The retaining piece 11 has a certain width B and is connected to the wall W of the liquid tank 5 by means of an adhesive joint L after fitting. Between the wall of the opening in the retaining piece 11 which faces the liquid tank and the wall of the liquid tank, an adhesive is applied which bridges the clearance between the retaining piece and the wall of the liquid tank. The supporting frame 6, 7, 8 thus provides a mechanical enclosure for the liquid tank which ensures that the forces which are exerted on the composite liquid tank during movement of the liquid tank container are diverted to the supporting frame.

The adhesive joint is produced using an adhesive or adhesive system which exhibits sufficient strength across a wide temperature range, from approximately -60°C to approximately 60°C, to which the liquid tank container may be exposed in the environment. Suitable adhesives are known to the specialist in this field.

It should be noted that the surfaces of the retaining piece 11 and the wall portion of the liquid tank which are connected to each other during fitting are prepared, for example, by cleaning and roughening said surfaces.

Figures 2a and 2b respectively show a side view and an end view of a second embodiment of a liquid tank container according to the invention.

In this embodiment, the liquid tank is configured to be self-supporting, so that the frame only comprises two subframes 6, 8. A subframe is provided at each end of the liquid tank and serves as end support near the end of the liquid tank 5. As the liquid tank is self-supporting, no horizontal support beams are necessary to connect the end supports to one another.

Each end support 6; 8 comprises a frame of horizontal and vertical girders 10a, 10b, as explained above with reference to Figures 1a, 1b.

Both end supports are connected to the liquid tank 5 by means of a retaining piece 11, as described above.

Furthermore, the end support in each case comprises a number of brackets 12a, 12b, 12c as further fastening means which together enclose the end. As the horizontal section of the external supporting frame is absent, this ensures that dynamic horizontal forces on the liquid tank can be transferred to the end supports to a sufficient degree.

In the illustrated embodiment, the brackets comprise a pair of bearing arms 12a, 12b, each of which is connected to a corner 13a; 13b of the end support and extend from the respective corner to the body axis C of the liquid tank.

Each bearing arm 12a; 12b has a curvature which substantially corresponds to the curvature of the end of the liquid tank in such a manner that the wall of the end of the liquid tank bears against the bearing arm. Furthermore, the end support 6; 8 comprises an upper retaining piece 12c which is provided with a profile which bears against the top side of the liquid tank.

In an embodiment, an adhesive joint may be provided on the surface between the brackets and the wall of the liquid tank.

Figures 3a and 3b respectively show a side view and an end view of a third embodiment of a liquid tank container according to the invention.

In this embodiment, the composite liquid tank 20 is completely accommodated inside a supporting frame 6, 7, 8 which consists of end supports 6, 8 and horizontal support beams (or horizontal supporting frame) 7.

The liquid tank 20 is composed of a substantially cylindrical central part 20a which is closed off at each end of the cylinder by an end cover 20b.

In this embodiment, on each cylinder end of the tank, the liquid tank 20 in each case comprises a collar 17, the circumference of which corresponds to the circumference of the cylinder portion 20a of the liquid tank 20. The end cover 20b is situated inside the collar 17.

Each of the end supports furthermore comprises a fastening means in the form of a retaining piece 14 which is provided with an opening inside which the collar 17 of the liquid tank is held.

As described above with reference to Figures 1a and 1b, the retaining piece 11 is substantially ring-shaped, has a certain width and is provided with a round opening inside which the collar 17 of the cylinder of the liquid tank is held. The shape and dimensions are such that the opening in the retaining piece 11 fits the circumference of the collar 17 of the liquid tank 20. The wall of the opening in the retaining piece 11 is connected to the wall of the collar 17 by means of an adhesive joint.

The supporting frame 6, 7, 8 thus provides a mechanical connection between the frame and the composite liquid tank by means of which dynamic forces on the liquid tank can be transferred to the frame.

Figures 4a and 4b respectively show a side view and an end view of a fourth embodiment of a liquid tank container according to the invention.

In this embodiment, the liquid tank 20 is configured to be self-supporting, so that the frame only comprises two subframes 6, 8. The composite liquid tank 20 is accommodated completely inside the frame. At each end of the liquid tank 20, a subframe 6; 8 is provided which acts as end support near the end of the liquid tank. As has been described above with reference to Figures 3a and 3b, the liquid tank 20 comprises a substantially cylindrical central part 20a with an end cover 20b at each end thereof. On each cylinder end of the tank, the liquid tank 20 in each case comprises a collar 17 whose circumference corresponds to the circumference of the cylinder portion. The end cover 20b is situated inside the collar 17.

The end supports each furthermore comprise a fastening means in the form of a retaining piece 14 which is provided with an opening inside which the collar 17 of the cylinder of the liquid tank is held.

As the liquid tank is self-supporting, no horizontal support beams are necessary to connect the end supports to one another.

The end supports 6, 8 do however each comprise a beam 21 on corners 15 of their frame, which beam is not at right angles to the end support and extends in the direction of the other end support, with one end 22 of the beam 21 serving as a fastening means and being connected to the wall of the liquid tank 20. The end 22 of each beam is in each case connected to the wall of the liquid tank by means of an adhesive joint.

Furthermore, it should be noted that, in an embodiment, the fastening means are provided with one or more additional adhesive surfaces which are in contact with the wall of the composite liquid tank in order to establish a connection between the end support and the liquid tank.

In an embodiment according to the invention, the end supports of the liquid tank container may be provided with engagement means (not shown) with which a lifting device (for example a crane, fork-lift truck or carrier) can engage in order to lift the liquid tank container.

It should furthermore be noted that in the above description, the retaining piece 11 comprises a ring-shaped or bush-shaped opening which encloses the wall of the liquid tank or the collar thereof.

It will be clear that the retaining piece 11 may also be composed of an interrupted ring shape which contains a number of ring segments with open intermediate spaces, which ring segments adjoin the wall of the liquid tank and are connected thereto by an adhesive joint.

Furthermore, it will be clear that the opening in the retaining piece is not limited to a round shape. Other shapes of the opening, such as an elliptic shape or a rectangular shape are possible if the wall of the liquid tank to which the retaining piece is to be connected has an elliptic or rectangular cross section.

Alternative and equivalent embodiments of the present invention are conceivable without departing from the inventive idea, as will be clear to the specialist in the field. The inventive idea is only limited by the attached claims.