Abstract: A heat exchanger has a plurality of parallel heat exchanger tubes with two plane sides and two narrow sides. The heat exchanger tube has a contour with a width and a height in a direction of flow of a first heat-exchanging medium such that the width is much greater than the height. Ribs are connected to the plane sides of the heat exchanger tubes. The ribs are made of a rib band folded to a meander-shape with bent portions. Adjacent ones of the ribs form a flow cross-section for a second heat-exchanging medium. The ribs have a plurality of openings wherein the size of the opening is at least equal in size to the size of the flow cross-section between adjacent ribs.

Abstract: A method for producing heat exchange elements having a tubular base body with ribs connected to the outer surface area for increasing the heat exchange surface area are especially suitable for base bodies having a cross-section with a width that is substantially greater than its height. According to the method, the ribs are produced by removing sheet metal strips from a roll and passing them through a corrugating device, positioning the corrugated sheet metal strips on lateral surfaces of the base body and welding the corrugated sheet metal strips to the base body. The application of the corrugated sheet metal strips, their positioning relative to the base body, and the transport of the base body in its longitudinal direction are effected by a special drive unit. For welding the sheet metal strips to the base body, laser heads are preferably used.

Abstract: An apparatus for the expansion of tube ends inside of a tube plate by means of a probe insertable in the respective tube ends, the probe forming an annular space with the tube member to be widened by means of two seals spaced from one another, a pump operatively feeding the annular space with a pressure medium for the expansion, and a pressure intensifier for bringing the pressure medium to a required pressure. A medium separator is connected via a back-pressure valve to a secondary-sided space of a primary-sided hydraulic oil driven pressure intensifier. A piston displaceably disposed in the medium separator is biased by a return spring in the medium separator, and the pump feeds the hydraulic oil displacing the piston against the restoring force of the return spring for the filling of the secondary space of the pressure intensifier with an operating medium. The operating medium flows from an operating medium-supply container and another back-pressure valve to the secondary side of the medium separator.

Abstract: A method of hermetically swaging tubes into the bores of heavy heat exchanger tube plates, by first expansion-swaging the inserted tube end portion under a very high hydraulic pressure and by then roll-swaging a portion of the expansion-swaged length portion, in order to replace the expansion-related tensile stress in the tubes with a compressive prestress, and in order to eliminate annular crevices at the inner edges of the tube plate bores.