Abstract: A pressure tank, particularly an elongated toroidal tank, with various lengths in X, Y, Z axes, includes bottoms connected with more than one connector, equipped with fixture connector pipes, holders for installation of the tank and cover, fixture cover, internal bottoms, internal casings, partitions. The external upper bottom and the external lower bottom form an external shell of the tank, with cross-sections having the shape of a rectangle with rounded vertices, whereas the internal casings are connected with the internal bottomw and/or with the external bottoms, preferably connected by the internal bottomw with middle tubes forming internal central connectors of the tank, separated by partition, and connector pipes are welded to tank walls so that the thickness of the external pipe wall is between 0.4 to 1.8 of the thickness of the walls of the tank elements.

Abstract: Subject of the invention is pressure tank, especially three-bottoms tank, creating beneficially toroidal tank, comprising connected bottoms, equipped with connector pipes for installation, brackets for fastening the tank and cover, type plate, equipment equipment cover, inner bottom, inner shell, divider and is characterized by that the outer, upper bottom (1) together with outer, lower bottom (2) create outer tank shell, whereas inner bottom (4) is connected with the inner shell (3), creating the central, inner part (S) of the tank, and connector pipes (9, 9a, 9b and 14) and flow connectors (15, 15a) have on their length two zones: zone A with walls of increased thickness and zone B—with walls of reduced thickness, beneficially on the whole circumference of connector, whereas the wall thickness in zone B is between 0.5 up to 1.7 of the thickness of tank elements when the wall thickness is between 0.01 up to 2.9 mm and 0.3 up to 1.4 for walls thick above 2.90 mm.