Abstract: A regenerator with a hollow cylindrical heat exchange roller which is provided with a jacket of heat carrier material with separated flow regions that are passed through by a flow medium emitting heat and a flow medium receiving heat. The hollow cylindrical roller has a partition wall which separates the flow regions. The flow media pass through the regions by substantially radial passages through the jacket and transverse to the axis of rotation of the heat exchange roller. A housing which holds the roller is provided with radial inlet and outlet channels for the flow media. These channels are displaced from one another by substantially 90.degree..

Abstract: A rotor for radial fans wherein the blades which are secured to the peripheries of the end walls surround or are surrounded by a spirally wound rod. The end portions of the rod are fastened to the end walls so as to maintain the median portion of the rod in prestressed condition. The rod enhances the resistance of the rotor to torsional stresses.

Abstract: A method of operating a burner system for the thermal post-combustion of waste air from industrial plants, in which the burning system includes a combustion chamber and a burner system opening into the combustion chamber is provided with supply pipes for the waste air through which it is conducted into the zone of the burner mouth inside the combustion chamber. A primary flame is produced which explodes into a fan at a point where the pipes open into the combustion chamber. The waste air is introduced into the combustion chamber approximately concentrically with and around the primary flame and the jet of waste air is divided into a large number of individual jet rays. The incoming waste air is given a twisting motion around the longitudinal median axis of the burner tube, and the primary flame is twisted in a direction opposite the direction of twisting of at least that part of the annular jet which is adjacent the primary flame.

Abstract: In a plant in which there is a circulating gas flow, an afterburner is provided which is supplied with fuel from outside the system. A part of the circulating gas is extracted and fed to the afterburner after passing in heat exchange relation with a part of the burnt gas. The heat produced in the burner is fed to the plant either by feeding the burnt gas back to the plant or through heat exchange between the burnt gas and the gas in the plant.