Abstract: Biological wastewater is purified in a sewage treatment plant having an activation tank of a depth greater than approximately 5 m per meter into which a feed of compressed air is fed. An oxygen-containing gas having an oxygen content is increased with respect to the air or pure oxygen and is fed to the mixed liquor in at least a part of the aerobic tank volume of the activation tank. The oxygen containing gas is fed until the total content of the gas in the mixed liquor based upon saturation value is below 150% before the mixed liquor is fed to a secondary clarification.

Abstract: The process for the direct preparation of cleaning solutions for semiconductor manufacture comprises producing the cleaning solutions directly at the site of use by mixing a gas with high-purity water, with a static mixer system being used. At least one of the gases NH3, HCl, ozone or HF is added.

Abstract: In an apparatus for producing perlite granules, having an expansion tube and one or more burners arranged at one end of the expansion tube, the combustion air is blown into the flame through one or more combustion air nozzles. An additional subsonic nozzle is arranged in at least one combustion air nozzle. In a process for expanding raw perlite in the updraft from a flame, with the introduction of oxygen or oxygen-enriched air into this flame, the oxygen or oxygen-enriched air is introduced axially into the flame through subsonic nozzles.

Abstract: The invention relates to a protective gas for TIG welding of metals, especially high alloy or low alloy steel, whose thermal conductivity is lower than that of aluminium. The inventive gas consists of argon, helium and hydrogen and enables significant improvements to be made in electric arc stability, welding speed, oxidation of weld surface and adjacent area, flow-on performance and weld appearance.

Abstract: An anesthesia system has ventilation gas supply flow structure for supplying ventilation gas to a patient. Structure is provided for the exhaled gas and for recycling the anesthetic gas-containing gas. The system uses a mass spectrometer connected to these flow structures to measure the content of at least one gas component in the gases and to control the flow through at least one of the flow structures in accordance with at least one measured value of the gas content.

Abstract: The apparatus for pelleting or granulating a liquid or pasty substance with a liquid cooling medium contains a pump (2) for the liquid cooling medium, a channel (5), open at the top and arranged horizontally or at an angle, for the liquid cooling medium, a feed device (4) for the substance to be pelleted, a return device (6) for the liquid cooling medium, and a heat-insulated conveying device (7). The apparatus is used in a method in which, by means of a gaseous cooling medium such as cold exhaust air, the pellets are not frozen through until in the region of the conveying device.

Abstract: In a process for transferring oxygen or an oxygen-containing gas into water or aqueous solutions in the treatment of water or aqueous solutions, oxygen or an oxygen-containing gas is added to the water or aqueous solution continuously or at intervals through an injector and simultaneously through at least one tube sparger.

Abstract: A method for operating a blast furnace includes feeding metallic charge materials, alloy elements and energy carriers in the upper part of the furnace shaft. An oxidizing agent is fed in the lower part of the shaft. Filler material, namely, alloy elements, metal chips, carbon, sands, dust are fed individually or in combination into the melting zone in at least one burst jet. Fuels may be introduced additionally into the first jet. The oxygen is fed at a high speed into the melting zone in at least one separate jet and the conditions of introducing the materials in the first jet and the oxygen in the second jet are controlled so that no flame can be formed.

Abstract: Process to avoid adhesions during the annealing of non-ferrous metal alloys, comprising the heating, holding and cooling phases, whereby the material being annealed is exposed to an inert or oxidizing protective-gas atmosphere during the structure transformation, as a result of which a thin oxide layer is formed during this time on the surface of the material being annealed and/or an oxide layer that was previously there is maintained, thus preventing the non-ferrous metal objects from adhering together.

Abstract: A process is disclosed for separating a component from a gaseous mixture, in particular for separating xenon from the breathing gas exhaled by an anaesthetized patient. The disclosed process has the following steps: the gaseous mixture is brought into contact with a cooling surface at a temperature below the melting point of the components to be separated, the proportion of the gaseous mixture which is not condensed on the cooling surface in a solid state is carried away, and the component condensed on the cooling surface is heated above the melting point of the component to be separated. Also disclosed are a device for carrying out this process, a corresponding process for recovering anaesthetic gas and an associated anaesthetic equipment.

Abstract: The invention relates to a coupling for connecting vacuum-insulated line ends (12, 13) via a coupling socket (11) and a coupling plug (10) which are provided for conveying a cryogenic medium and which have closing elements (28, 29) at the outer line ends that close the line ends. In order to ensure a simple replacement of the gaskets and improved safety during operation and in case of operating errors, the closing elements (28, 29) of both line ends (12, 13) are directly adjacent to the separation plane (27) of the coupling socket (11) and of the coupling plug (10).

Abstract: The invention relates to a coupling for connecting vacuum-insulated line ends via a coupling socket and a coupling plug which are provided for conveying a cryogenic medium and which have closing elements at the outer line ends that close the line ends. So that the valve-like means can be opened or closed by remote control in a defined manner, the coupling plug (10) has a control unit (43) that is connected to the closing element (29) and that opens at least the closing element (29) when exposed to control pressure.

Abstract: The invention provides a method and a device for monitoring the filling of a tank with a liquid, deep-frozen gas, in which the temperature and the pressure of the liquid gas in the tank are recorded, and the mass of the liquid gas in the tank is calculated from the temperature and the volume. In the prior art, a system with an overflow was used as a filling-level limitation, in which case the height of the overflow took the maximum increase in volume into account. With this limitation of the filling level, because the phase boundary is only determined independently of the density, the maximum permissible filling level must take into account the maximum possible increase in volume of the liquid gas. With the system according to the invention, better utilization of the tank volume is possible, because the increase in volume actually possible is taken into account based on the actually prevailing pressure and temperature state of the liquid gas introduced.

Abstract: Liquid is sprayed in two partial streams into a tank filled with a gas atmosphere and collects at the bottom of the tank. One partial stream sprayed into the atmosphere prevalent collects at the bottom of the tank. At least one other partial stream is fed into the liquid collected at the bottom of the tank. The partial streams are withdrawn from a shared liquid supply.

Abstract: A process for automatic filling with products, particularly of gas into gas cylinders, utilizes electronic comparison of the data stored in a data carrier located on the tank with the actually measured weight of the tank makes it possible to determine the degree of residual filling in the tank as well as to ascertain whether the tank weight is too low which, under certain circumstances, can give rise to safety risks and, in response, to either remove the tank from the filling process or else to fill it.The process and the device function fully automatically, so that it is possible to save personnel costs.

Abstract: The process and device according to the invention make it possible to reduce the pressure build-up in the head space as a function of the quantity of inflow medium. It also makes it possible to maintain or create defined flow conditions in the head space gas. This is accomplished by measuring the quantity of gaseous and/or liquid inflow medium and then venting the head space gas as a function of the quantity of inflow medium.

Abstract: The invention relates to a process and an apparatus for grinding and sifting a product, in which the product is embrittled by a coolant and is comminuted in a mill (8), the comminuted product being fed, after comminution while keeping away ambient air and the moisture this involves, to a sifter (14). With the process and the apparatus according to the invention, the product can be comminuted and sifted in a closed-loop process without separating agents having to be fed to the ground product prior to sifting to overcome electrostatic charging. The sifter (14) is preferably operated with the gaseous coolant which is used to operate the mill (8) so that any losses of sifter circuit gas occurring during sifting can be compensated by feeding in a gaseous coolant. The total duration of the process can be reduced considerably.

Abstract: When reactors charged with nitrogen as inert-blanketing gas are opened, high losses of inert-blanketing gas occur which previously have only been able to be compensated for by increased feed of inert-blanketing gas. To minimize the consumption of inert-blanketing gas during temporary opening of reactors (1), a further inert-blanketing gas is admixed to the nitrogen. The inert-blanketing gas mixture in the process has a density which is slightly greater than the density of the surrounding air.

Abstract: The prior art discloses machines which, for cooling the surface to be machined, have a gas supply line which opens into a gas outlet which is in the direct vicinity of the polishing disk. When CO.sub.2 is used as cooling gas, stoppages, which can be traced back to snow formation of the CO.sub.2, may occur in the line and in the gas outlet. In order to avoid blockages, the machine is assigned means for the supply of the liquid or supercritical CO.sub.2 which comprise a valve for regulating the throughflow quantity of the CO.sub.2 with an expansion nozzle, the valve being arranged inside the machine.

Abstract: When cold strip is annealed, diffusion welds, so-called stickers, frequently form on the strip surface. In order to avoid these, the cold strip, above 600.degree. C. (holding time) is coated by oxidation with a thin surface film which prevents the sticking together. Below 600.degree. C., during the cooling phase, this surface film is removed again by reduction. In the case of a protective gas comprising a hydrogen content greater than 5%, remainder nitrogen, carbon dioxide is preferably added as oxidizing agent. The process is controlled via a defined oxygen partial pressure. The reduction is performed via the hydrogen.