Abstract: The fin for a heat exchanger which consists essentially of a matrix of tubes and of fins disposed transversely to the latter, the fin having pass-through elements to receive tubes which are to be joined mechanically, while a first, preferably liquid medium flows through the tubes and the fin is acted on by a second, preferably gaseous medium. Multiple fins are positioned in their fin pitch by integral spacers, wherein the spacers are in the form of noses stamped out of the pass-through elements and distributed over the periphery of the latter.

Abstract: A heat exchanger, produced by the insertion of welded pipes into a rib pack, has a good connection between the rib pack and the pipes after expansion of the pipes. An optimal contact of the pipes against the passages in the cooling fins of the rib pack is achieved because the weld base of the welded pipe lies in a recess. The recess is formed by reduction of the wall thickness of a strip material from which the welded pipe is produced.

Abstract: A method and a device for the draw expansion of metal tubes of oval cross-section uses expansion elements drawn unidirectionally through metal tubes by means of draw elements. The expansion elements are fastened to the draw elements by suspension devices which have a hammer-like contour. The draw elements are preferably made of a rod-shaped material. An apparatus of the invention is an apparatus for mechanically expanding metallic tubes, in particular tubes in heat exchangers. Each individual tube to be expanded is held in at least one holding device and passed through by a drawing mandrel with an expanding element. To prevent jamming of the expanding element in one of the holding devices, the holding devices are provided with lateral guides which are resiliently compliant outward in the radial direction. When the expanding element passes through the metallic tube, the tube is expanded in the radial direction.

Abstract: The fin for a heat exchanger which consists essentially of a matrix of tubes and of fins disposed transversely to the latter, the fin having pass-through elements to receive tubes which are to be joined mechanically, while a first, preferably liquid medium flows through the tubes and the fin is acted on by a second, preferably gaseous medium. Multiple fins are positioned in their fin pitch by integral spacers, wherein the spacers are in the form of noses stamped out of the pass-through elements and distributed over the periphery of the latter.

Abstract: A heat exchanger, particularly for motor vehicles, including a collecting tank and a metallic tube plate which has a primary side, a secondary side, and collars which are formed on it, and in which collars tubes are to be held and sealed. Neighboring collars (17, 19) are alternately directed towards the primary side (22) and towards the secondary side (23). In other words, collars disposed side by side are alternately formed in the direction of the air side and of the water side, whereby the distance between the collars can be reduced to a minimum.

Abstract: A cooling system for a vehicle having an internal-combustion engine has a plurality of cooling circuits with heat exchangers for each circuit. The temperatures of different cooling media are measured and processed in a switching device to form an output signal which serves to control a fan. In this way, the air flow through the heat exchangers can be varied depending on measured temperature conditions. Individual capacity control of each cooling circuit is possible, thereby preventing unfavorable operating conditions in the individual circuits. The cooling capacity demand of the individual cooling circuits is determined by a central control unit which receives signals from temperature sensors in each circuit. The central control unit includes a microprocessor. Each cooling circuit has an actuating means for individually controlling the capacity of the relevant heat exchanger.