Abstract: In the preparation of a graphite body suitable for use as a cathode in an electrolytic process, comprising the steps ofa) contacting a graphite body with a solution in at least one polyhydric alcohol having 2 to 4 carbon atoms of at least one of an iridium salt and rhodium salt for a time sufficient for the solution to penetrate through the surface of the graphite body to a depth of at least about 1 mm, andb) heating and then cooling the graphite body,the improvement which comprises effecting the heating by contacting the surface of the graphite body into which the solution has penetrated with a naked gas flame positioned above such surface, the graphite body being heated to about 200.degree. to 450.degree. C. for about 2 to 10 minutes.

Abstract: A dimensionally stable anode comprised ofa) an electrically conductive valve metalb) a conductive intermediate layer andc) an electrode coating of an electrocatalytically active substance, wherein the intermediate layer comprises one or more noble metals or their alloys which have been applied to the valve metal by deposition by electroplating from melts containing noble metal salts. This anode can be used in the production alkali metal dichromates and chromic acid by electrolysis of alkali metal monochromate and/or alkali metal dichromate solutions.

Abstract: A process for the preparation of alkali metal dichromates and/or chromic acid by electrolysis of alkali metal monochromate and/or alkali metal dichromate solution in electrolysis cells, the anode and cathode compartments of which are separated by cation exchange membranes, wherein the cation exchange membranes are single-layer membranes based on perfluorinated polymers having sulfonic acid groups as cation exchange groups, and an aqueous solution having a pH of 4 to 14 is produced in the cathode compartment of the cells.

Abstract: The invention relates to a process for the preparation of alkali metal dichromates and chromic acid by the electrolysis of monochromate and/or dichromate solutions in a multi-chamber cell, wherein the anode chamber is shielded from the solution of chromate, dichromate and/or chromic acid by a bipolar ion exchanger membrane.

Abstract: A process for the preparation of alkali metal dichromates and chromic acid by the electrolysis of monochromate and/or dichromate solutions in an electrolytic cell in which the anode and cathode chamber are separated by a cation exchanger membrane anolyte fluid containing dichromate and/or chromic acid being formed in the anode chamber and alkaline catholyte fluid containing alkali metal ions being formed in the cathode chamber, the improvement wherein the catholyte fluids are periodically replaced by a solution which is at a pH below 6.

Abstract: A process for the preparation of chromic acid by the electrolysis of dichromate and/or monochromate solutions in electrolytic cells in which the anode chamber and the cathode chamber are separated by a cation exchanger membrane, the improvement wherein the chromic acid content of the solution in the anode chamber is periodically increased above that of a continuous operating state.

Abstract: A process for the production of chromic acid by the multistage electrolysis of dichromate and/or monochromate solutions in two-compartment electrolysis cells, of which the anode and cathode compartments are separated by cation exchanger membranes, at temperatures in the range from 50.degree. to 90.degree. C., the dichromate and/or monochromate solutions being obtained by the digestion of chrome ores and leaching, the improvement wherein, optionally after the removal of aluminum, vanadium and other impurities, the monochromate solution obtained after leaching is adjusted at 20.degree. to 110.degree. C. to a pH value of from 8 to 12 by the addition and/or in situ formation of carbonate in a quantity of from 0.01 to 0.18 mol/l (for 300 to 500 g/l Na.sub.2 CrO.sub.4, converted with CO.sub.

Abstract: A process for the preparation of alkali metal dichromates and chromic acid by the electrolysis of monochromate and/or dichromate solutions in an electrolytic cell in which the anode and cathode chambers are separated by cation exchange member, the improvement wherein the formation of deposits on the membrane is prevented comprising continuously introducing a solution containing chromate at a pH of about 3 to 10 into the cathode chamber during the electrolysis.

Abstract: A process for the production of alkali dichromates and chromic acid by electrolysis of alkali monochromate or alkali dichromate solutions wherein the anodes used in the electrolysis are dimensionally stable anodes of valve metals activated by electrodeposition of noble metals and/or noble compounds from melts containing noble metal salts.

Abstract: A supercharged internal combustion engine for a drive system of land vehicle with an air filter (18) and a charging air manifold (12) connected with each other by several flow paths (21, 22, 23) for the combustion air. Each flow path (21, 22, 23) is equipped with a check valve (19, 36, 26) while the flow path (22) is additionally equipped with a controllable closure device (20) and the flow paths (22, 23) are equipped with one charging air compressor (27, 31) each. The charging air compressor (27) includes a drive by an exhaust gas turbine (28). The charging air compressor (31) is driven by an electric motor (32) with permanent magnet energization, whereby the energy for feeding the electric motor (32) is supplied by a generator (33) energized by permanent magnet and driven by the internal combustion engine (11). Depending on the operating condition of the internal combustion engine (11), one of the flow paths or several flow paths are simultaneously in operation.

Abstract: An internal combustion engine with several cylinders, with one or several superchargers, and with an additional compressor-drive by means of compressed gas, in which during partial load of the internal combustion engine, some cylinders operate as engine while the other cylinders which operate in the meantime as compressors, supply compressed gas for the additional compressor-drive of each supercharging aggregate that supplies the cylinder operating as combustion engine with charging air.

Abstract: A woven diaphragm for a diaphragm electrolysis cell for electrolysis of aqueous solutions containing ions such as alkali metal ions, chloride ions, and sulfate ions which diaphragm comprises warp threads and weft threads. Both warp threads and weft threads are of multifil filaments. Weft threads contain less than about 200 per meter and warp threads contain less than 400 per meter.

Abstract: In the treatment of a perfluorinated polymer membrane containing acid ion exchanger groups in a corona discharge, the improvement which comprises employing a membrane containing carboxyl groups and maintaining the membrane at a temperature below about 80.degree. C. during the discharge treatment. Advantageously the corona discharge treatment is carried out intermittently, the temperature is maintained at about -10.degree. to +22.degree. C., during the treatment the average rate of irradiation is below about 2 Ah/m.sup.2, the frequency of the corona discharge is from about 5 to 15 kHz, the voltage for producing the corona discharge is from about 1 to 20 kV and the dose is from about 0.1 to 10 Ah/m.sup.2 of membrane surface. The resulting membranes exhibit lowered resistance resulting in lower cell voltages when used in the electrolysis of sodium chloride.

Abstract: An internal combustion engine with several cylinders and with one or several supercharging aggregates, in which at partial load of the engine, some cylinders operate as engine while the remaining cylinders, operating in the meantime as compressor, supply compressed gas to the turbine of a further supercharging aggregate whose compressor is connected in series with the compressor of that supercharging aggregate which supplies the cylinders operating as engine with supercharging air.

Abstract: An internal combustion engine which is supercharged by exhaust gas turbochargers and which includes an auxiliary combustion chamber. Exhaust gases from the auxiliary combustion chamber are temporarily fed to turbines of the exhaust gas turbocharger for improving acceleration characteristics of the internal combustion engine. The combustion air for the auxiliary combustion chamber is derived from the stream of supercharging air produced by the turbochargers. At least two exhaust turbochargers are provided which operate in parallel. In case of acceleration of the engine, the exhaust gases from the internal combustion engine circumvent the turbines of the exhaust gas turbochargers, and then the exhaust gases of the auxiliary combustion chamber alone effect the drive for all exhaust gas turbochargers.

Abstract: In an electrolytic cell for the production of chlorine and hydrogen from hydrochloric acid, the cell comprising a plurality of spaced bipolar electrodes each provided with vertical grooves for the passage of gas, and a plurality of diaphragms each subdividing the space between adjacent electrodes, the improvement which comprises providing the grooves with a depth of about 18 to 35 mm at least in the upper part of the electrodes. Advantageously the grooves have a width of about 2 to 3 mm and the spacing between adjacent grooves of each electrode is about 4 to 6 mm, the depth of the grooves at their bottoms is about 12 to 15 mm and increases in upward direction to about 20 to 30 mm, and the distance between the electrodes and the diaphragms is from about 0.05 to 1 mm. The voltage drop and energy consumption are less than with different groove configurations and the chlorine content of the hydrogen gas is reduced.

Abstract: An internal combustion engine which is adapted to be supercharged by at least two exhaust gas turbochargers operating in parallel. The engine includes an auxiliary combustion chamber, the exhaust gas of which is temporarily fed to a turbine of an exhaust gas turbocharger for improving an acceleration characteristic of the internal combustion engine. Combustion air for an idling operation of the auxiliary combustion chamber is derived from a stream of supercharging air produced by the exhaust gas turbocharger. During a partial load operation of the engine, only one of the exhaust gas turbochargers is supplied with an entire volume of the exhaust gas of the internal combustion engine to provide the supply of supercharging air. The exhaust gas from the auxiliary combustion chamber, operated with a full load for the case of accelerating in a lower load range of operation of the internal combustion engine, is fed to the turbine of the other exhaust gas turbocharger.

Abstract: The sodium concentration in the amalgam of an electrolysis cell is automatically monitored by periodically removing an amalgam sample of predetermined quantity from the end compartment of the electrolysis cell, introducing the sample into a reference cell containing a reference electrolyte, thereby to form a galvanic element in said reference cell, discharging the galvanic element, and measuring the charge flowing out when the galvanic element is discharged, the charge being an index of the sodium concentration. Advantageously the reference electrolyte is a dilute solution of at least one of sodium hydroxide and sodium chloride. The apparatusincludes many cells and a common distant monitoring station.