Abstract: An exhaust manifold and a method for manufacturing an exhaust manifold that includes a housing part and overlapping corrugated sheet parts having corrugations at an angle of 10 to 60 degrees relative to each other. The method includes the steps of preoxidizing the manifold parts and after the preoxidation step joining the manifold parts simultaneously to each other by resistance welding.

Abstract: This publication discloses a reactor cell useful for the treatment of gases, and the manufacturing method thereof. The corrugated sheet (2, 3, 6) of the metal reactor cell (1, 11, 41) is connected with joints (5) to another sheet (2, 3, 4, 6) to form channels (9) in the reactor cell, the number of said joints (5) at least in some part of the reactor cell (1) being 10 to 1000 per cm3. The reactor cell (51, 52) may be inserted into a housing (57) having conical sections. They can be joined to each other or to housing or to the part of the housing by joints made by resistance welding.