US20070205192A1

US20070205192A1 - Container with container side walls made of metal, container bottom portion made of metal and container lid made of metal

Info

Publication number: US20070205192A1
Application number: US11/398,674
Authority: US
Inventors: Manfred Roth
Original assignee: Roth Werke GmbH
Current assignee: Roth Werke GmbH
Priority date: 2006-03-01
Filing date: 2006-04-06
Publication date: 2007-09-06
Also published as: EP1829800A1

Abstract

A container with container side walls made of metal, a container bottom portion made of metal and a container lid made of metal, characterized in that the container side walls are joined with each other and/or with the container bottom portion and/or with the container lid, at least in certain areas, by means of a cold pressing technique. The container side walls and/or the container bottom portion and/or the container lid are, at least in certain areas, provided on outsides with a zinc coating and on this zinc coating a polymer coating is applied.

Description

The invention relates to a container with container side walls made of metal, a container bottom portion made of metal and a container lid made of metal. The container according to invention is used for transporting and storing liquid, granular and powdery media, in particular as a tank for storing heating oil, fuels, for example Diesel fuel, and the like. Furthermore, the invention relates to a method for producing a container with container side walls made of metal, a container bottom portion made of metal and a container lid made of metal.
Containers of the kind described above are known from practical experience. They are particularly double-walled containers with an external container, within which an inner container is accommodated, serving particularly for the storage of heating oil, fuels, and waste oil. The external container comprises container side walls, a container bottom portion and container lid made out of steel sheet. The inner container is usually made of plastic, particularly of polyethylene. Many of the known containers have the disadvantage that the external container still requires improvement in terms of its impermeability and/or diffusion impermeability. Many known containers are also. In need of improvement in terms of the corrosion resistance of the external container. This also applies to the stability of the external container.
The invention is based on the technical problem of providing a container of the kind described above, which does not have any of the preceding disadvantages, and which is characterized by optimal impermeability as well as excellent corrosion resistance and, furthermore, by high stability. Moreover, a container is to be disclosed, which satisfies all the requirements in terms of its appearance.
To solve this technical problem, the invention provides a container with container side walls made of metal, a container bottom portion made of metal and container lid made of metal, wherein for example by a cold pressing technique the container side walls are joined with each other and/or with the container bottom portion and/or with the container lid, at least in some areas,
wherein the container side walls and/or the container bottom portion and/or the container lid, at least in certain areas on their external sides, are provided with a zinc coating and wherein to this zinc coating a polymer coating is applied.
The container according to invention is used particularly for storing heating oil, fuels and the like. The container side walls, container bottom portion and container lid are suitably made of steel and/or steel sheet. According to the invention, the container side walls are joined with each other and with the container bottom portion and/or with the container lid by cold-pressed connections and/or a cold pressing technique.
Furthermore, the invention provides that also the container bottom portion comprises, at least in certain areas of its outside and/or bottom, a zinc coating and that to this zinc coating of the container bottom portion a polymer coating is applied. The container bottom portion is suitably joined with at least one part of the side walls by means a cold pressing technique. The zinc coating and the applied polymer coating are present at least in those areas on the outside of the container bottom portion, which are cold pressed with the container side walls. The container bottom portion is preferably provided with the zinc coating and the polymer coating applied thereon on the entire surface of its outside and/or substantially on the entire surface.
Suitably, the zinc coating with the applied polymer coating is provided at least on those external areas of the container side walls, which are cold-pressed with additional container elements, particularly with the container bottom portion. According to a preferred embodiment of the invention, the container side walls are provided with the zinc coating and the polymer coating applied thereon across the entire surface and/or substantially across the entire surface.
According to the invention, the container comprises a container lid, which on the outside and/or upper side, at least. In certain areas, is provided with a zinc coating, on this zinc coating a polymer coating being applied and the container lid on the outside being joined, at least in certain areas, with the container side walls by means of a cold pressing technique. Suitably, the container lid is provided with the zinc coating and the applied polymer coating on the outside at least in those areas, which are cold-pressed with the container side walls. The container lid is preferably provided with the zinc coating and the polymer coating applied thereon across the entire surface and/or substantially across the entire surface of the outside.
A particularly preferred embodiment of the invention is characterized in that the container side walls and/or container bottom portion and/or container lid on the inside are provided with a zinc coating. According to this embodiment of the invention, a polymer coating on the zinc coating of the container inside is not necessarily required. Nevertheless, a polymer coating can also be present on this inside zinc coating. The container side walls, container bottom portion and container lid preferably are fully zinc-coated metal parts and/or steel sheet parts.
These fully zinc-coated metal parts and/or steel sheet parts are then suitably provided on the outside with the polymer coating. The term outside of the metal parts and/or steel sheet parts relates to the assembled state of the pans, in which the respective outsides define the outside of the container.
According to the invention, all joining areas of the container side walls with each other, of the container side walls with the container bottom portion and of the container side walls with the container lid are provided with cold-pressed joints. According to a particularly preferred embodiment of the invention, at least on a portion of the cold-pressed areas, preferably on all cold-pressed areas, sealing elements and/or sealing strips are inserted. These sealing elements and/or sealing strips suitably extend along the cold-pressed areas.
According to a particularly preferred embodiment of the invention, a U-shaped casing element and/or casing sheet forming the container bottom portion and two container side walls is provided, which element or sheet is joined with two additional container side walls. The other two container side walls at the same time form the front walls and/or front sheets of the container. According to the invention, the container bottom portion and the container side walls of the casing element are joined with these two additional container side walls at the joining areas by cold pressing. The casing element and/or casing sheet suitably comprises, at least in these joining areas, the outside zinc coating and the polymer coating applied thereon. The two additional container side walls also preferably comprise, at least in the joining areas, the outside zinc coating with the polymer coating applied thereon. According to a particularly preferred embodiment of the invention, the casing element and/or casing sheet is provided with the zinc coating and polymer coating across the entire surface and/or substantially across the entire surface of the outside. The two additional container side walls are also preferably provided on the outside with a zinc coating and the applied polymer coating across the entire surface and/or substantially across the entire surface. According to the invention, the container lid made of metal is joined with the container side walls of the U-shaped casing element by means of cold pressing, and also with the two additional container side walls by means of cold pressing. The container lid, at least in the joining areas with container side walls, is provided on the outside with a zinc coating and the polymer coating applied thereon. The container lid preferably comprises a zinc coating and a polymer coating applied thereon across the entire surface and/or substantially across the entire surface of the outside.
The container side walls can also comprise a one- or multipart, ring-shaped casing and/or metal casing, the lower edge of which is joined with the container bottom portion by means of a cold pressing technique. For this embodiment of the invention, the zinc coating of the casing and of the container bottom portion on the outside of the container, with the polymer coating applied thereon, has proven reliable.
According to the invention, the container is configured as a double-walled container. In which the container side walls and the container bottom portion and preferably the container lid form an external container and in which a preferably plastic inner container is disposed inside the external container. Suitably the side walls, bottom portion and lid of the inner container are made of plastic. The inner container preferably comprises polyolefin, particularly polyethylene. Furthermore, the invention provides that between the container side walls of the external container and side walls of the inner container an intermediate space is formed. To this intermediate space, suitably a leak monitoring device is connected. This way, leakages on the inner container can be reliably detected. The double-walled container is of great importance according to the invention. Due to the design according to invention and/or the connection of the container side walls, the container bottom portion and the container lid, a surprisingly tight enclosure of the inner container and/or the intermediate space between the external container and inner container can be achieved.
According to the invention, the connection created by means of the cold pressing technique is a flanged connection, a riveted joint or folded seam connection. “Joined by means of a cold pressing technique” means in particular a connection and/or cold-pressed connection by means of flanging, riveting or folding. The flanged connection is of great importance according to the invention. According to a preferred embodiment of the invention, the container side walls are also flanged with each other and/or with the container bottom portion on the edges and/or on the edge areas. This configuration produces an absolutely tight container area for the storage media. According to a preferred embodiment of the invention, the container lid is additionally tightly applied. The container lid is preferably joined with the container side walls by means of flanging or riveting and suitably by interposing sealing material. The term cold pressing, according to a preferred embodiment of the invention, refers to a flanged connection. A surprisingly gas-tight container is created by flanging the container elements according to invention.
A particularly preferred embodiment of the invention is characterized in that the zinc coating thickness on the outside of the container side walls and/or on the outside of the container bottom portion and/or on the outside of the container lid is 5 to 40 μm, preferably 8 to 35 μm, preferred 10 to 30 μm, very preferred 12 to 28 μm and particularly preferred 15 to 25 μm. Suitably, also the zinc coating thickness of the inside of the container side walls and/or the inside of the container bottom portion and/or the inside of the container lid is 5 to 40 μm, preferably 8 to 35 μm, preferred 10 to 30 μm, very preferred 12 to 28 μm and particularly preferred 15 to 25 μm. It is recommended that the zinc coating be provided on the outside of all container elements with the aforementioned thickness, and also suitably on the inside of all container elements. Container elements and/or elements here refer to the container side walls, container bottom portion and container lid.
According to a very preferred embodiment of the invention, the polymer coating thickness on the zinc coating of the outside of the container side walls and/or the outside of the container bottom portion and/or the outside of the container lid is 0.2 to 6 μm, preferably 0.3 to 5 μm, preferred 0.4 to 4.5 μm and very preferred 0.4 to 4 μm. One embodiment variant of the invention is characterized in that the polymer coating thickness is 0.4 to 3.7 μm, suitably 0.4 to 3.4 μm, preferably 0.5 to 3 μm, preferred 0.5 to 2.5 μm and very preferred 0.6 to 2.4 μm.
According to the invention, the polymer coating comprises at least one thermoplastic polymer. According to a particularly preferred embodiment, the polymer coating is transparent. The polymer coating is in particular a clear varnish. According to the invention, the preferred transparency of the polymer coating has proven advantageous.
According to a preferred embodiment of the invention, the polymer coating is applied as an aqueous polymer dispersion and/or aqueous polymer dispersion solution. The polymer dispersion suitably comprises 15 to 40% by weight, preferably 18 to 37% by weight, preferred 22 to 35% by weight and very preferred 25 to 31% by weight of a polymer. The preceding % by weight ranges also relate to a particularly preferred polymer mixture. The polymer dispersion suitably comprises 50 to 80% by weight, preferably 54 to 76% by weight, preferred 58 to 72% by weight and very preferred 62 to 70% by weight of water. Furthermore, the polymer dispersion comprises preferably 1 to 10% by weight, preferred 2 to 9% by weight, very preferred 3 to 8% by weight and particularly preferred 3 to 7% by weight of an additive. It is recommended to use a compound from the elements of the secondary table of elements as the additive, particularly a titanium compound or chromium compound. According to a preferred embodiment of the invention, the additive for the polymer dispersion and/or the polymer coating additive is a titanium compound. Preferably 4 to 6% by weight of the titan compound is present in the polymer dispersion. The above-described additive serves in particular as a corrosion inhibitor. According to a preferred embodiment of the invention, the polymer dispersion comprises a mixture of at least one polyurethane resin and of at least one polyacrylate resin. Preferably both aforesaid resins are comprised as polymers in the polymer dispersion. The polymer dispersion suitably comprises 50 to 80% by weight, preferably 55 to 75% by weight, preferred 58 to 68% by weight and very preferred 60 to 66% by weight of polyurethane. Furthermore, in addition to the aforementioned polyurethane content, the polymer dispersion suitably comprises 18 to 45% by weight, preferably 23 to 40% by weight, preferred 26 to 36% by weight and very preferred 28 to 34% by weight of polyacrylate.
The invention furthermore relates to a method for producing a container with container side walls made of metal and a container bottom portion made of metal, wherein on the outside of the container side walls and/or outside of the container bottom portion a zinc coating is applied, wherein on this zinc coating a polymer coating is applied and the container side walls are joined with each other and/or with the container bottom portion at least in certain areas by means of a cold pressing method. According to the invention, also on the outside of the container lid a zinc coating is applied, and on this zinc coating a polymer coating is then applied, and the container lid is joined with the container side walls by means of a cold pressing method. Suitably, according to the method of the invention, the container side walls and/or the container bottom portion and/or the container lid are produced as fully zinc-coated metal parts and/or steel sheet parts and subsequently the polymer coating is applied to the outside these fully zinc-coated metal parts and/or steel sheet parts. Fully zinc-coated metal parts and/or steel sheet parts means that the container side walls and/or container bottom portion and/or container lid are zinc-coated on the outside as well as on the inside. According to a particularly preferred embodiment of the invention, the polymer coating is applied by means of a rolling method to the zinc coating on the outside of the container side walls and/or the container bottom portion and/or the container lid. The polymer coating, according to a particularly preferred embodiment of the invention, is also rolled on.
As illustrated above, according to a preferred embodiment of the invention, steel sheets are used for the container side walls, for the container bottom side and for the container lid. According to the invention, the zinc coating and the polymer coating are initially applied to the steel sheets and the steel sheets are then formed for the container side walls, the container bottom portion and the container lid.
The invention is based on the fact that due to the inventive design of the container and/or the external container the container according to invention is distinguished by a surprisingly high impermeability. In this context, the combination the according to invention of the external polymer-coated zinc coating of the container with the cold pressing of the container elements is of great importance. This combination effectively results in the surprisingly high impermeability at the joining points between the container elements. The container/external container produced according to invention has an excellent liquid and diffusion impermeability and, as long as the container lid is tightly applied, is characterized by gas tightness and by a durable odor absorption, due to the overall tightly sealing metal enclosure. The metal enclosure according to invention also prevents the penetration of odor-producing dirt particles into the container/external container. Furthermore, it is also of great importance that configuration of the container elements the according to invention offers optimal long-lasting corrosion protection. The invention is furthermore based on the fact that the container and/or external container according to invention is characterized by excellent stability, wherein this stability is also guaranteed in the long term. The aforementioned combination according to invention effectively contributes to this characteristic. The polymer-coated layer guarantees, particularly in the area of the cold-pressed points, optimal protection of the joining points against chemical and/or physical effects. This guarantees a long-lasting stability of the joining points. The container according to invention can, for example, also sustain higher water pressure levels without a problem. The external coating of the container/external container according to invention corresponds to a very resistant long-lasting coating, which does not permit any undesirable changes, for example due to white rust, to the external container appearance. The external coating according to invention for example also prevents undesirable clouding of the container surface as a result of incident light. The external coating according to invention offers furthermore an effective seal, which prevents, for example, that dirt, fingerprints and the like adhere to the container surface. In principle the external coating of the container according to invention guarantees a very aesthetic external appearance with a modern metallic sheen. It should also be stressed that the container according to invention can be produced by using relatively inexpensive measures. In conclusion, compared to the state of the art, the container according to invention is distinguished by considerable advantages.
The invention will be explained in more detail hereinafter with reference to one embodiment that is schematically illustrated in the figure, wherein:
FIG. 1 is an exploded view of the design of a container according to invention,
FIGS. 2 a to d are schematic illustrations of the production of a flange connection according to invention and
FIG. 3 is a section through a container wall according to invention.
In FIG. 1 a container according to invention is illustrated, configured here as a double-walled tank. The tank comprises an external container 1 and an inner container 2 accommodated in the external container 1. This tank according to invention is in particular intended for storing heating oil, diesel fuel, lubricants and hydraulic oils, and the like. The inner container 2 is suitably made of plastic, preferably of polyethylene. The external container 1, as in the exemplary embodiment, is preferably made of fully zinc-coated steel sheet elements. This external container 1 comprises container side walls 3, 4, a container bottom portion 5 as well as a container lid 6. The container lid 6 is conventionally provided with openings.
In the exemplary embodiment according to FIG. 1, a U-shaped casing sheet 7 forming the container bottom portion 5 and two container side walls 3, which casing sheet is connected to two additional container side walls 4. The additional container side walls 4 at the same time form the front walls of the external container 1. The container lid 6 is then placed on and fixed to the assembly comprising the container side walls 3, 4 and container bottom portion. In the exemplary embodiment, the casing sheet 7 (container side walls 3 and container bottom portion 5), the container side walls 4 and the container lid 6 are made of fully zinc-coated steel sheets. In other words, these container elements comprise an external zinc coating 8 as well as internal zinc coating 9. These zinc coatings 8, 9, as shown in the exemplary embodiment, preferably have a thickness of 18 to 22 μm. On the external zinc coating 8 of the container side walls 3, 4, the container bottom portion 5 and the container lid 6 a polymer coating 10 is applied. This polymer coating 10 preferably comprises at least one thermoplastic polymer and is preferably transparent. The polymer coating 10 in particular corresponds to a clear varnish made of thermoplastic polymer.
According to invention, the edges of the container side walls 3, 4, the container bottom portion 5 and the container lid 6 are joined by means of a cold pressing technique. Of particular importance is the fact that in the cold-pressed areas the external zinc coating 8 with the polymer coating 10 applied thereon is provided, as well as the inner zinc coating 9. According to a preferred embodiment of the invention, the cold pressing step of the container side walls 3, 4, the container bottom portion 5 and container lid 6 is provided by flanging. This flanged connection according to invention has proven to be particularly advantageous
FIGS. 2 a to d show four preferred work processes when producing a flanged connection according to invention. Here the edges 11, 12 of the container side walls 3 and 4 are joined by means of flanging. The two container side walls 3, 4 are first joined as is shown in FIG. 2 a and thereafter the actual flanging operation is carried out, so that the design displayed in FIG. 2 b is achieved. According to the steps shown in FIGS. 2 c and d, the flanged connections at the same time are bent, so that no sharp edges are created to the outside, but only non-interfering rounded areas. Of course the processes shown in FIGS. 2 a to d can be performed with a flanging tool, which is not shown in detail. According to a preferred embodiment of the invention, sealing elements, which are not shown in detail, are inserted in the cold-pressed connections, preferably in the flanged connections prior to the cold pressing operation. The sealing elements are suitably sealing stripes, which extend along the cold-pressed connections. The sealing elements are preferably clamped between the container elements joined by cold pressing at the cold-pressed locations.
In FIG. 3 a section through a preferred container side wall 3 according to invention is shown. Accordingly constructed are also preferably the container side walls 4, the container bottom portion 5 and the container lid 6. The container elements are suitably made of a steel sheet 13, which comprises a zinc coating 8, 9 on both sides. On the external zinc coating 8 a polymer coating 10 is applied. The external zinc coating 8 is preferably more than twice as thick, preferably more than three times as thick as the polymer coating 10. The thickness of the external zinc coating 8 in the exemplary embodiment may be 20 μm. The thickness of the external polymer coating 10 in the exemplary embodiment is 0.8 to 2 μm. According to a particularly preferred embodiment, the polymer coating 10 is transparent. The polymer coating 10 is preferably roiled on the external zinc coating 8 of the steel sheet 13.
Between the container side walls 3, 4, of the external container 1 and the inner container 2 incidentally an intermediate space is provided, which is not shown in detail in the figures. According to a preferred embodiment of the invention, a leak monitoring device can be connected to this intermediate space. This way, leaks on the inner container 2 can be reliably detected. The external container 1 according to invention guarantees a highly impermeable enclosure of the inner container 2, so that the external container 1 is configured completely impermeable against leakages.

Claims

1. A container comprising container side walls (3,4) made of metal, a container bottom portion (5) made of metal and a container lid (6) made of metal, characterized in that the container side walls (3,4) are joined with each other and/or with the container bottom portion (5) and/or with the container lid (6), at least in certain areas, by means of a cold pressing technique, the container side walls (3, 4), at least in certain areas on their outside, being provided with a zinc coating (8) and on this zinc coating (8) a polymer coating (10) being applied.

2. A container according to claim 1, wherein the container bottom portion (5) on the outside, at least in certain areas, comprises a zinc coating (8), on which a polymer coating (10) is applied.

3. A container according to any one of the claims 1 or 2, wherein the container lid (6) on the outside, at least in certain areas, comprises a zinc coating (8), on which a polymer coating (10) is applied, the container lid (6) being joined to the container side walls (3, 4) by means of a cold pressing technique.

4. A container according to any one of the claims 1, 2 or 3, wherein a U-shaped casing element (7) forming the container bottom portion (5) and two container side walls (3) is joined with two additional container side walls (4).

5. A container according to any one of the claims 1 to 4, wherein the container is configured as a double-walled container, the container side walls (3, 4) and the container bottom portion (5) as well as the container lid (6) forming an external container (1) and in this external container (1) an inner container (2), which is preferably made of plastic, being accommodated.

6. A container according to any one of the claims 1 to 5, wherein the connection established by means of a cold pressing technique is a flanged connection, a riveted joint or a folded seam connection.

7. A container according to any one of the claims 1 to 6, wherein the thickness of the zinc coating (8) on the outside of the container side walls (3, 4) and/or on the outside of the container bottom portion (5) and/or on the outside of the container lid (6) is 5 to 40 μm, preferably 8 to 35 μm and preferred 10 to 30 μm.

8. A container according to any one of the claims 1 to 7, wherein the thickness of the polymer coating (10) on the zinc coating (8) of the outside of the container side walls (3,4) and/or on the zinc coating (8) of the outside of the container bottom portion (5) and/or on the zinc coating (8) of the outside of the container lid (6) is 0.2 to 6 μm, preferably 0.3 to 5 μm, preferred 0.4 to 4.5 μm and very preferred 0.4 to 4 μm.

9. A container according to any one of the claims 1 to 8, wherein the polymer coating (10) is transparent.

10. A method for producing a container comprising container side walls (3, 4) made of metal, a container bottom portion (5) made of metal and a container lid (6) made of metal, characterized in that to the outside of the container side walls (3,4) and/or to the outside of the container bottom portion (5) and/or to the outside of the container lid (6) a zinc coating (8) is applied, on which zinc coating (8) a polymer coating (10) is applied, the container side walls (3,4) being joined with each and/or with the container bottom portion (5) and/or with the container lid (6), at least in certain areas, by means of a cold pressing method.