Abstract: Specified is a heat exchanger, in particular an exhaust-gas heat exchanger or charge-air heat exchanger, for exchanging heat between a first fluid, in particular an exhaust gas or charge air, and a second fluid, in particular a coolant, which heat exchanger has: a block for separate and heat-exchanging guidance of the first and second fluids; a block closure element for connecting the block to a fluid connection. In order to eliminate the problems which occur in particular during a soldering process and to reduce thermal stresses in operation, the block closure element has a contact face arranged at the block side, with a surface normal of the contact face being aligned substantially in a radial direction in order to form a radial stop for a block edge, and a cohesive connection, in particular as a soldered connection, is formed in a joining region between the contact face and the block edge. The invention specifies an arrangement and a method for producing the heat exchanger.

Abstract: The invention relates to a heat exchanger, particularly in tube bundle-type, panel-type or plate-type design. The heat exchanger has a housing inside of which a number of flow channels are formed for a primary flow and a secondary medium, and the housing has a sandwich design.

Abstract: A skate, such as a roller skate or inline skate, comprises a shoe, a chassis and rollers or wheels suspended in the chassis. The skate also includes a braking system for at least one of the rollers or wheels. The braking system comprises a braking element which engages the roller and includes at least one actuation element for acting on the braking element. The braking force of the braking system is obtainable at low rotational or rolling speed of the roller to be braked and is small and increases with increasing rotational or rolling speed of the roller to be braked.

Abstract: The invention is directed to a document shredder (1) driven by an electric motor (2), with a stepdown gear train (4, 5, 7, 8) arranged between the drive and the cutting mechanism (9). Hitherto these appliances were powered by AC motors, which operate already relatively slow cutting speed when shredding low quantities of paper sheet layers, and in which the breakdown torque occurs at a very early stage. Prejudices existed up to now against the use of DC motors in document shredders because of a number of reasons. In the invention a DC motor (2) especially a series-wound motor is now used as a drive for a document shredder (1). It has the decisive advantage, of enabling a high cutting speed with small quantities of paper layers, which decreases approximately continuously as a function of the quantity of paper layers, wherein stoppage is to be expected only with very high quantities of paper layers.