Abstract: The invention concerns a heat exchanger comprising a heat exchanger block having a plurality of tubes and fins arranged transversely to the tubes, at least one tube plate and a water tank, both made of a synthetic plastic material. The tube plate has orifices to receive the ends of the tubes and the water tank is fastened in a water tight manner to the tube plate. In order to obtain a simple and reliable joint of the heat exchanger tubes with the tube plate and the water tank with the tube plate, the plastic tube plate is provided on one side with projections. The orifices are located in these projections and the ends of the tubes are mounted in these orifices by expansion in the radial direction or impression in the axial direction. Both the tube plate and the water tank are equipped with flat surfaces at their edges. These surfaces rest on each other and the tube plate is joined with the water tank by vibration welding on these surfaces.

Abstract: A heat exchanger wherein a plurality of individual tubular parts are connected with each other is provided having a common pressure element for tube connections arranged in a plane. According to FIG. 1, a pressure platen 6 is present, which consists of a material harder than that of the external tubular part and is equipped with a number of orifices 7 corresponding to the number of tube connections. The pressure platen 6 surrounds the outer and inner tubular parts inserted in each other, and the diameter of the orifices 7 is smaller, at least in part, than the external diameter of the outer tubular part. According to the process for the manufacture of the heat exchanger, all of the tube connections are produced simultaneously by means of pressing on the pressure platen. Each of the tube connections is effected by reducing the cross section by means of plastic deformation of at least the outer, tubular part, whereby a press fit of the tubular part is obtained.

Abstract: A fluid friction clutch comprising a rotatable assembly comprising a clutch housing member and a clutch cover member defining a working chamber therein, the working chamber being connected with a working fluid reservoir, valve lever means in said reservoir for controlling the admission of working fluid from the reservoir to the working chamber where it serves to transfer torque between a rotatable disc disposed in the working chamber and said rotatable assembly, means for actuating the valve lever means comprising a pressure chamber formed from a pressure chamber housing and a flexible membrane carrying a pressure plate which directly engages the valve lever means, the pressure chamber housing and membrane being joined to the rotatable assembly to rotate therewith, and means for introducing a pressure medium such as compressed air into said pressure chamber to actuate the valve lever means and control the admission of working fluid from the reservoir into the working chamber, said pressure medium introducing

Abstract: A support matrix for a catalytic reactor for scrubbing exhaust gases in internal combustion engines, made of high-temperature resistant steel made up of alternating steel panels, at least one of which is corrugated, and at least one of which is provided with projections or depressions interlocking with at least one adjacent steel panel.