Abstract: A heat exchanger with a housing comprising two chambers separated by a partition plate, with each chamber comprising an inlet opening and an outlet opening for fluids. The housing and the partition plate are formed from a single metal sheet, the partition plate is formed from a middle area of the metal sheet, comprising a plurality of ribs and channels running alternately in parallel, and the housing is formed from side areas of the metal sheet which are folded along bend lines.

Abstract: The heat exchanger having a heat exchanging channel (11, 21, 31) comprises an inlet (9) and an outlet (33) for a medium flowing through the heat exchanging channel. The heat exchanger has at least two stages (10, 20, 30) being arranged one after the other in view to the flowing direction of the medium, each stage having a heat exchanging channel (11, 21, 31). The first stage has at least one guiding channel (12) arranged parallel to the heat exchanging channel (11). The heat exchanging channel (11, 21, 31) has at the end of the respective stage (10, 20, 30) at least one outlet (13, 23, 33) and the guiding channel (12, 22) of the respective stage is connected with the heat exchanging channel (21, 31) of the next following stage (20, 30). By this unused heat transfer medium is fed to each stage, said heat transfer medium having a higher temperature difference with respect to the respective heat exchanging channel. By this a good heat transfer efficiency is realized even with relatively long flow pathes.

Abstract: A method for producing a filter element involving applying a membrane layer to a carrier substrate, etching a membrane chamber, producing pores in the membrane layer, subjecting the membrane layer to an additional treatment to increase the mechanical strength.

Abstract: A method for the production of filters in which a blank of n- or p-doped etchable semiconductor material is connected as an anode or a cathode according to doping. The method includes contacting a first side of the blank with an etching solution in which a counterelectrode is arranged to electrochemically etch the first side, and supplying activation energy to generate minority charge carriers to the blank during the etching process. The activation energy supplied per unit time is reduced with increasing etching progress.