Abstract: A heat exchanger includes a tube bottom made of pressure-resistant and temperature-resistant plastic, and a plurality of tubes which are disposed in side-by-side relationship in the tube bottom and form at least indirectly part of a distribution and/or collecting chamber. The tubes have tube ends which are each provided with a circumferential securing member to inhibit extraction of the tubes from the tube bottom when the tube ends are firmly secured in the tube bottom through a casting process or injection process.

Abstract: A heat exchanger includes a tube bottom made of pressure-resistant and temperature-resistant plastic, and a plurality of tubes which are disposed in side-by-side relationship in the tube bottom and form at least indirectly part of a distribution and/or collecting chamber. The tubes have tube ends which are each provided with a circumferential securing member to inhibit extraction of the tubes from the tube bottom when the tube ends are firmly secured in the tube bottom through a casting process or injection process.

Abstract: The finned tube heat exchanger (1) has a plurality of elongated heat exchanger tubes (2) arranged parallel to one another and with a cross section, the length (L) of which is a multiple greater than its width (B). The heat exchanger tubes (2) are interconnected by fins (3) extending parallel to the direction of flow (SR) of the cooling air. Parallel adjacent air conduction grooves (7) running in the direction of flow (SR) of the cooling air, open at the fin ends (6) and in zig-zag array are made on at least one side surface of the fins (3). Said grooves are semicircular in cross section and consist of straight groove sections (8) and arc-shaped transition sections (9) steplessly interconnecting said straight sections. The groove sections may also be a component of zig-zag fin sections. Thus the groove sections still run obliquely to the longitudinal run of the fins.

Abstract: A supporting belt (3) for ribs (7), carrier belts (6) for the ribs (7) arranged adjacent to the supporting belt (3), a feed (8) for the ribs (7), and a fusion welding device (11) (laser beams, electron beams) which welds half-tubes (10) with the ribs (7) contacting the outer sides of the latter (10) proceeding from the inner sides are used to provide tubes with ribs. After providing the half-tubes (10) with ribs, the latter are connected with additional ribbed half-tubes (10) by means of welding the longitudinal edges (27) to form exchanger tubes. These exchanger tubes can then be galvanized individually or in bundles as heat exchangers.

Abstract: An arrangement for utilizing the heat contained in the exhaust gas from a coal-fired boiler for preheating feed water for the boiler and for preheating primary air. The arrangement includes a rotating heat transfer unit and lines for conducting exhaust gas and preheated combustion air to the heat transfer unit. A heat shifting unit is connected in parallel to the heat transfer unit. A line conducts primary air to the heat shifting unit and another line conducts cooled exhaust gas from the heat transfer unit to the heat shifting unit. The exhaust gas line and the cooled exhaust gas line connecting the heat transfer unit and the heat shifting unit are connected through a bypass which bridges the heat transfer unit. The bypass includes a heat exchanger and/or steam generator, wherein the boiler feed water flows through the heat exchanger and/or steam generator.

Abstract: A heat exchanger includes exchanger tubes which are narrow in flow direction of an outer exchanger medium. Always two adjacent exchanger tubes are connected to each other by fins which are either U-shaped individual or are components of a meander-like fin strip. The tube sides are connected to bases of the individual fins or to contact portions of the fin strips by welding, particularly by fusion welding on the inner surfaces of the tube sides. The exchanger tubes are formed by two tube shells which are welded together at the longitudinal edges thereof after two adjacent tube shells have been connected to each other by the fins. The ends of the tubes are placed in tube plates. The resulting heat exchanger is completely galvanized and does not require support structures.

Abstract: A method and an apparatus for the denitrification and desulfurization of hot waste gases, particularly from furnaces. A crude gas flow is initially conducted through a denitrification plant and through the endothermic part of a heat-utilizing plant. Subsequently, the flow is conducted into a desulfurization plant. The purified gas flow discharged from the desulfurization plant is conducted through the exothermic part of the heat-utilizing plant and is subsequently transferred to ambient. By means of a cooling trap, a portion of the heat contained in the crude gas flow before the contact with the heat-utilizing plant is removed while precipitating sulfuric acid in the form of vapor, and this heat is then added to the purified gas flow before the contact thereof with the heat-utilizing plant.

Abstract: An arrangement for the catalytic oxidation of the harmful components in a cooled carrier gas from a technical process. The arrangement includes two parallel gas ducts which are connected at one end through a bend and whose other ends are connected to gas lines for the carrier gas and for purified gas. The gas ducts are connected to each other through a three-stage thermal energy return unit. The exchanger stage of the thermal energy return units are arranged spaced from each other and are composed of individual heat tubes whose number increases from exchanger stage to exchanger stage. The size ratio of the heat-exchanging surfaces of heating part to cooling part of each exchanger stage decreases in flow direction of the carrier gas from exchanger stage to exchanger stage. The catalyst is integrated in the gas duct for the carrier gas immediately downstream of the heating part of the last exchanger stage.