Abstract: A large dimension hollow body such as a fuel tank is formed from cold deformable sheet metal by cutting a sheet metal blank of a conformation matching the hollow structure to be formed and which has a nonuniform cross section between its ends. The sheet metal blank is then formed into a three-dimensional shape closed at one end and subjected to hydrostatic forming, whereupon the other end is closed optionally after insertion of an object to be received in the tank such as a fuel pump. The welding of the edges of the blank together and the application of the caps can produce pressure-tight weld seams and can be effected by laser-beam welding or tungsten inert gas welding.

Abstract: For the sterilization of liquids (43) containing harmful microorganisms, or for the conditioning of mixtures of substances, a process and a heat exchanger (1) in the form of a tubular heat exchanger are used. The tube bundle (3) between the intake flange (2) and the outlet flange (4) is comprised of a number of tubes (18, 20) that are equal in length and that possess a narrow flow area and thin walls. These tubes, characterized as capillary tubes, are connected via distribution canals (15, 16) that are equal in length and similar in cross-section, to the central tube (12, 13) in the intake flange and in the outlet flange (2, 4). This causes the residence time distribution in the heat exchanger (1) to be held within very narrow limits, and causes the medium to be heated within fractions of a second to, for example, 140° C. or more, or less. This ensures a sterilization with the best possible preservation of thermolabile components, such as vitamins and proteins.

Abstract: A heat-exchanger tube has an inner tube wall centered on an axis, formed with an outwardly projecting helical ridge having a helical outer surface, and forming an outwardly open helical groove delimited by the ridge and an outer tube wall centered on an axis, formed with an inwardly projecting helical ridge of the same hand as the inner-tube ridge, having a helical inner surface, and forming an inwardly open helical groove delimited by the outer-tube ridge. The inner tube is coaxially received in the outer tube with the grooves together forming a helical passage having a plurality of turns and the surfaces radially confronting and spaced from each other to form an axial passage for fluid communication between adjacent turns of the helical passage. A fluid is fed to one end of the helical passage and withdrawn from an opposite end with flow of the fluid helically along the helical passage and axially through the axial passage.