Quasi-cylindrical cargo container and construction
A quasi-cylindrical cargo container is formed of a plurality of rigid, curved panels together forming first and second semi-cylindrical shells, and a plurality of rigid, flat extension panels bridging the first and second semi-cylindrical shells. A method of manufacturing the container includes forming the first and second semi-cylindrical shell from the curved panels, forming the quasi-cylindrical shell from the first and second semi-cylindrical shells and the flat extension panels, forming collars conformably encompassing the quasi-cylindrical shell, constricting the collars to compress joints formed at abutting edges of pairs of adjacent panels, rolling the shell and collars sequentially to bring the joints to a lower position, welding inside seams of the joints when at the lower position, removing the collars, rolling the shell sequentially to bring the joints to an upper position, and welding outside seams of the joints when at the upper position.
1. A method of manufacturing an obround cargo container, the method comprising:
providing a plurality of longitudinal panels formable into an obround shell having a transverse cross section with an obround shape, the panels comprising:
rigid curved panels formable into a cylindrical shell, each curved panel comprising a cylinder segment of the cylindrical shell; and
at least two rigid, flat extension panels;
forming the obround shell from the panels;
forming at least one collar conformably encompassing the obround shell;
constricting the at least one collar to compress longitudinal joints formed at abutting edges of pairs of adjacent panels; and
welding respective joints of pairs of the panels.
2. The method according to claim 1 , wherein, prior to constricting the collars, the obround shell is free of tack welds.
3. The method according to claim 1 , wherein welding the respective joints of pairs of the panels comprises:
moving the respective joints of the pairs of panels to a lower position, and welding respective inside seams of the joints when at the lower position.
4. The method according to claim 3 , further comprising, after welding the inside seams of the joints:
removing the at least one collar from the obround shell;
moving the respective joints of the pairs of panels to an upper position; and
welding respective outside seams of the joints when at the upper position.
5. The method according to claim 3 , wherein moving the respective joints of pairs of panels to the lower position comprises rolling the obround shell and at least one collar to bring the respective joints of pairs of panels to the lower position, wherein rolling the obround shell and at least one collar comprises rolling the obround shell and at least one collar together about a longitudinal axis of the obround shell, wherein rolling the obround shell and at least one collar comprises rolling the obround shell and at least one collar together using a rolling apparatus.
6. The method according to claim 5 , wherein the rolling apparatus comprises a tank roller.
7. The method according to claim 3 , wherein, prior to welding the inside seams of the joints of the pairs of panels, the obround shell is free of tack welds.
8. The method according to claim 3 , wherein forming the obround shell from the panels comprises:
forming a first semi-cylindrical shell from a first set of the curved panels;
forming a second semi-cylindrical shell from a second set of the curved panels; and
forming the obround shell from the first semi-cylindrical shell, the extension panels, and the second semi-cylindrical shell.
9. The method according to claim 8 , wherein each of the at least one collar comprises a pair of ring segments formable into the collar sized and shaped conformably to encompass the obround shell.
10. The method according to claim 9 , wherein forming the first semi-cylindrical shell from the first set of the panels comprises:
providing a cradle comprising a first set of the ring segments longitudinally spaced and aligned concentrically to form a semi-cylindrical frame conforming to the first semi-cylindrical shell; and
laying the first set of the panels in the cradle so as to abut respective longitudinal edges of each pair of adjacent panels to form the first semi-cylindrical shell.
11. The method according to claim 10 , wherein forming the second semi-cylindrical shell from the second set of the panels comprises:
assembling the second set of the panels so as to abut respective longitudinal edges of each pair of adjacent panels to form the second semi-cylindrical shell.
12. The method according to claim 11 , wherein forming the obround shell from the first semi-cylindrical shell, the extension panels, and the second semi-cylindrical shell comprises:
laying the extension panels atop the first semi-cylindrical shell so as to abut respective longitudinal edges of the extension panels and corresponding outermost adjacent panels of the first set of panels; and
laying the second semi-cylindrical shell atop the extension panels so as to abut respective longitudinal edges of the extension panels and corresponding outermost adjacent panels of the second set of panels,
wherein the abutting respective longitudinal edges of each pair of adjacent panels forms a joint.
13. The method according to claim 12 , wherein forming the at least one collar conformably encompassing the obround shell comprises:
laying a second set of the ring segments atop the obround shell and above the first set of ring segments in pairwise fashion so as to oppose respective adjacent ends of each pair of ring segments thereby forming the collars conformably encompassing the obround shell.
14. The method according to claim 13 , wherein constricting the at least one collar to compress the longitudinal joints formed at abutting edges of pairs of adjacent panels comprises:
clamping the obround shell by constricting the collars using constricting means provided at the opposing respective adjacent ends of each pair of ring segments, thereby compressing at least some of the pairs of longitudinal panels at their respective joints.
15. The method according to claim 12 , wherein the respective longitudinal edges of each pair of adjacent panels comprise a tongue and a groove, and the joint is formed by mating the tongue of one panel with the groove of the abutting panel.
16. The method according to claim 15 , further comprising:
after forming the first semi-cylindrical shell from the first set of the panels, and before forming the obround shell from the first semi-cylindrical shell, the extension panels, and the second semi-cylindrical shell, placing at least one spacer in the first semi-cylindrical shell, the at least one spacer spacing at least some of the panels to maintain the obround shape of the obround shell.
17. The method according to claim 16 , wherein the at least one spacer has an obround shape matching the obround shape of the transverse cross section of the obround shell.
18. The method according to claim 17 , wherein placing the at least one spacer in the first semi-cylindrical shell comprises placing the at least one spacer upright in the first semi-cylindrical shell so as to contact respective inside surfaces of at least some of the panels of the first semi-cylindrical shell whereby the first semi-cylindrical shell supports the at least one spacer.
19. The method according to claim 18 , wherein forming the second semi-cylindrical shell from the second set of the panels, and forming the obround shell from the first semi-cylindrical shell, the extension panels, and the second semi-cylindrical shell, further comprises:
laying the second set of the panels atop the extension panels and the at least one spacer so as to abut the respective longitudinal edges of each pair of the adjacent panels to form the second semi-cylindrical shell atop the extension panels, and so as to abut the respective longitudinal edges of the outermost panels for the second set of panels and the extension panels, wherein:
the at least one spacer contacts respective inside surfaces of at least some of the panels of the second semi-cylindrical shell, supports the second semi-cylindrical shell, and maintains a semi-cylindrical shape of the second semi-cylindrical shell.
20. The method according to claim 19 , further comprising, after constricting the at least one collar to compress the longitudinal joints formed at the abutting edges of pairs of adjacent panels, and before welding the respective inside seams of the joints when at the lower position:
removing the at least one spacer, whereby an interior of the obround shell is unobstructed.
21. The method according to claim 20 , wherein the at least one spacer comprises at least one spacing disk, wherein the at least one spacing disk comprises a first semi-disk, a rectangular plate, and a second semi-disk configured for rigid assembly to form the spacing disk and configured for disassembly, wherein removing the at least one spacer comprises disassembling the at least one spacing disk and removing the disassembled at least one spacing disk from the interior of the obround shell.
22. The method according to claim 20 , wherein the at least one spacer comprises at least one spacing ring comprising a rim formed with an outer U-shaped channel sized and shaped fittingly to receive an inflatable tube, wherein removing the at least one spacer comprises deflating the inflatable tube to reduce pressure between the inflatable tube and an inside surface of the obround shell, and removal of the spacing ring from an interior of the obround shell.