A container (10) is produced from a spiral-shaped, bent sheet strip (20) having a first edge section (22) extending in a spiral shape, being bent, and forming a bending edge (24) extending in a spiral shape toward the inside or the outside of the container (10). The sheet strip (20) has a second edge section (32) opposite the first edge section (22) in the longitudinal direction of the sheet strip (20) and extends in a spiral shape. The second edge section (32) overlaps a third section (28) opposite the first edge section (22) in relation to the bending edge (24) and is adjacent to the bending edge (24). The second edge section (32) and the third section (28) are welded to each other in the region of the overlap (30). The welding seam (40) extends at least partially into the region between the second edge section (32) and the third section (28) of the sheet strip (20).

A container is produced from a single-layered, helically bent sheet metal strip. In the strip's upper or lower border region a first helically running border portion of the strip is bent out via a helically running outwardly bent edge with a curved region toward the outside of the container as a protruding flange. A second helically running border portion is in the lower/upper border region. The border regions each border one another adjacently height-wise and are connected to one another in a fluid-tight manner via a continuous, helically running welded joint. The second border portion runs rectilinearly in the plane of the strip and the welded joint has a first and a second weld seam. The first and second weld seams are applied from the outside and the inside of the container, respectively, and the two weld seams are fused to each other in the weld route thereof.

The method for forming from a round shaped cylinder to a square shaped cylinder which can be inserted in a square or rectangular shape metal container (shipping container and frac tanks) includes initiating turning of a heated mandrel, extruding heated polymer, wrapping while compressing a first layer of heated polymer, disposing a mesh layer over the cylinder encapsulating the cylinder on the turning mandrel while simultaneously laying a second layer of heated polymer over the turning mandrel and compressing the layer of heated polymer into the mesh layer and the mesh layer into the first layer of heated polymer simultaneously, and repeating the layering of the heated polymer and mesh layer until a desired wall is reached. The method forms a hybrid polymer square or oval tank or a hybrid polymer round, which achieves over 95 percent of the total volume of the metal container.

The method for forming from a round shaped cylinder to a square shaped cylinder which can be inserted in a square or rectangular shape metal container (shipping container and frac tanks) includes initiating turning of a heated mandrel, extruding heated polymer, wrapping while compressing a first layer of heated polymer, disposing a mesh layer over the cylinder encapsulating the cylinder on the turning mandrel while simultaneously laying a second layer of heated polymer over the turning mandrel and compressing the layer of heated polymer into the mesh layer and the mesh layer into the first layer of heated polymer simultaneously, and repeating the layering of the heated polymer and mesh layer until a desired wall is reached. The method forms a hybrid polymer square or oval tank or a hybrid polymer round, which achieves over 95 percent of the total volume of the metal container.

A container is produced from a single-layered, helically bent sheet-metal trip (20). A first, helically running peripheral portion (22) of the sheet-metal strip (20) is bent out in the direction of the outside of the container (10) to form a helically running bent out edge (24). A second, helically extending peripheral portion (26) of the sheet-metal strip (20) overlaps a third portion (28) of the sheet-metal strip (20) on the inside of the container (10). The third portion is adjacent to the bent-out edge (24) and extends in the direction of the second peripheral portion (26) from the bent out edge (24). The second peripheral portion (26) is connected in a fluid-tight manner to the third portion (28) of the sheet-metal strip (20) on the inside of the container (10).

There is provided a manufacturing method of a tank including a liner. The manufacturing method comprises (A) a process of winding fibers in a sheet-like form impregnated with a resin on a mandrel having a higher rigidity than rigidity of the liner and heating and curing the wound fibers in the sheet-like form to form a sheet layer; (B) a process of pulling out the mandrel from the sheet layer; and (C) fitting the liner into the sheet layer, after the process (B).