Abstract: A series of primary-air orifices (4) extend into the combustion chamber surrounded by a housing (1). A sloping bottom (6) and a grate (12), likewise inclined at an angle (.alpha.), are located underneath. The grate consists of a row of parallel pipes (15a to 15c) which are arranged at a distance from one another and which are provided over their entire length with air outflow orifices (16a, 16b). A covering slide (13) sliding in grooves (17) on the grate makes it possible to cover to a greater or lesser extent both the gaps between the grate pipes (15a to 15c) and, if appropriate, some of the air outflow orifices provided in the grate pipes. The covering slide (13) can be actuated by hand or by means of a motor via a rack (20) connected rigidly to it and via a pinion (19).

Abstract: A high current-rectifier arrangement comprising a movable contact body which is of substantially piston-like structure and arranged with radial play in a cylinder-like compartment or chamber formed in an associated contact element and surrounded at its periphery by a connection line which bridges the radial play to the inner wall of the compartment. Furthermore, cooling agent-channel means of such contact body are arranged in offset relationship at the periphery thereof with respect to the connection line and sealingly connected with cooling agent-channels provided in the connection element.