Abstract: To effect a quasi-isothermal catalytic reaction of SO.sub.2 to SO.sub.3, a plurality of consecutive rows of banks of cooling tubes, are provided in the bed of shaped catalyst bodies in a contact reactor in such a manner that the banks of succeeding rows are staggered from the banks of the preceding rows. The distance between the cooling tubes in the banks is so selected that a penetration of entire catalyst bodies into the banks will virtually be prevented. The banks are so designed that the pressure drop of the gas in the banks is approximately the same as the pressure drop in the layer of catalyst between the bank. The distance between the banks is larger than the width of the banks.

Abstract: o-Hydroxy-benzaldehydes can be obtained by oxidation of the o-cresols, on which they are based, with oxygen in the presence of substances having a base reaction in a solvent if chelate complexes of iron, manganese or a mixuture of both with polyaza-macrocycles as chelating agents are employed as catalysts. Copper or a copper compound is advantageously added as a co-catalyst.

Abstract: In flue gases or other humid exhaust gases which are relatively cold and contain SO.sub.2, NO.sub.2 and other gaseous pollutants, the SO.sub.2 content is oxidized to SO.sub.3 and the NO content is reduced by a catalytic treatment, the SO.sub.3 content is condensed as sulfuric acid and other gaseous pollutants are removed by being scrubbed with aqueous liquids at low temperatures. In order to heat up the flue gas to the temperature required for the catalysis, the flue gas is heated up in a first heating-up stage by an indirect heat exchange with the catalytically treated gas before the catalytic treatment, the heated-up gas is heated up further in a second heating-up stage to the temperature required for the catalytic treatment, the catalytically treated gas which has been cooled in the first heating-up stage is cooled further in an indirect heat exchanger below the dew point temperature of sulfuric acid and is subsequently fed to an SO.sub.3 condenser.

Abstract: Flue gases or other contaminated humid exhaust gases which contain SO.sub.3 are cooled by an indirect heat exchange in a heat exchanger to a temperature below the dew point temperature of sulfuric acid and are cooled further to a predetermined temperature in an SO.sub.3 condenser by means of dilute sulfuric acid, which is sprayed to flow in a countercurrent to the gas, whereby dilute sulfuric acid having a predetermined concentration is condensed. The gas leaving the SO.sub.3 condenser is scrubbed and cooled to a temperature from 40.degree. to 55.degree. C. in a fine scrubber by a treatment with a sprayed aqueous liquor. The exit gas is reheated to a predetermined temperature in a reheater by a treatment with sprayed dilute sulfuric acid from the SO.sub.3 and after the condensation of SO.sub.3 is passed through a filter. Dilute sulfuric acid from the reheater is sprayed into the SO.sub.3 condenser.

Abstract: Cleaned flue gases normally accumulate as steam-saturated gases with temperatures of from 40.degree. to 55.degree. C. after wet cleaning processes for the removal of sulfur and/or nitrogen compounds. Before being let off through a stack, however, these gases have to be heated to at least 72.degree. C.This invention relates to a process for reheating flue gases after wet cleaning.

Abstract: To facilitate assembly of an automotive alternator, the alternator housing (11) is separated into two axially split half-shells (11a, 11b), the dividing line (11c) preferably passing through the axis of the shaft (18) of the alternator. The alternator assembly is made by providing a subassembly including the shaft, electromagnetic rotor structure, bearings, and a disk element in which rectifier diodes are seated and which can also support holders in engagement with the slip rings and the voltage regulator. The stator is slipped around the subassembly, a fan wheel and pulley can be attached to the subassembly which is then placed into one half-shell. The bearings and the concentric elements are positioned in alignment by seats formed in the half-shell, and the axial alignment can be accurately checked, and if the alignment is found proper, the second half-shell is assembled thereover.

Abstract: A support carrier of electrically conductive material is secured to the shaft of the machine. A plurality of slip rings are secured to the support carrier, one of the slip rings being fixed thereto directly so that the support carrier will form one terminal of the electrical connection for the slip rings, and an insulating layer is placed over the support carrier over which the other slip ring is located. Preferably, the support carrier is formed with a flange which is notched, one of the notches serving to form an electrical connection for the wire of the field of the machine for connection to the slip ring which is directly secured to the support carrier, the other notch in the flange being wider and gripping around the insulation of the other wire of the field, the wire of the field then being connected to the slip ring which is carried on the insulation. That slip ring, preferably, is also formed with an external flange to which its connecting wire can be secured, for example by soldering.