Abstract: An alternating pressure apparatus for obtaining oxygen from the air has two adsorbers to which an air blower for adsorption air and a vacuum pump stand for desorption are connected. The vacuum pump stand has two vacuum pumps in tandem. In a partial load operation characterized by low O.sub.2 removal; and during the lower pressure equalization of the adsorbers, the vacuum pump stand is connected to the air blower in that in each case the vacuum valve, connecting one adsorber to the vacuum pump stand, and the air valve, connecting the same adsorber to the air blower, are opened at the same time.

Abstract: An alternating pressure apparatus for obtaining oxygen from the air has two adsorbers to which an air blower for adsorption air and a vacuum pump stand for desorption are connected. The vacuum pump stand has two vacuum pumps in tandem. The second vacuum pump in the direction of flow is configured as a rotary piston pump with preliminary inlet cooling for the defined inflow of outside air at atmospheric pressure. The inlet of the second vacuum pump is connected to the outlet of the first vacuum pump without the use of gas cooling by water injection or by a heat exchanger. The alternating pressure apparatus operates with a desorption pressure between 300 mbar and 500 mbar.

Abstract: A vacuum pumping stand for the cyclic pumping-down of containers and for maintaining an operating vacuum in the containers, for the pumping-down of the container. The vacuum pumping stand has a first and a second vacuum pump which are arranged in series and form a first and a second pumping stage. The first vacuum pump is a radial flow compressor with a controllable throttle which is located in the intake pipe to the first vacuum pump. The second vacuum pump is a rotary compressor or a water ring pump. The second vacuum pump is located in a vacuum pipe in parallel to an outlet pipe of the first vacuum pump and is connected with its inlet at a branch-off with the outlet pipe. A control part is situated in each of the outlet pipe and the vacuum pipe downstream of the branch-off for directing the delivered volume at higher pressures from the first vacuum pump directly or at lower pressures from the first vacuum pump by way of the second vacuum pump 13 to the outlet 10 of the vacuum pump stand.

Abstract: The invention relates to a method and apparatus for the purification and recirculation of gases which are fed to a plant for the production of metal powder or for compacting metal powder at elevated pressures. The operating gas exits the plant at a lower pressure and is conveyed in a closed loop, in which filters are provided for the mechanical and/or chemical purification of the gases as well as means for increasing the pressure of the purified gas. The repressurization of the operating gas is carried out economically by liquefying the operating gas leaving the plant after purification by the application of liquid nitrogen, then feeding the liquefied gas to an evaporator via a high-pressure pump, and finally returning the operating gas to the plant in a pressurized gaseous phase.

Abstract: Disclosed is an apparatus for cleaning sulphur and nitrogen containing flue gases by adding gaseous reagents and by a reaction in a reaction chamber which the reactants pass through in the axial direction and are exposed to at least one electorn beam. The apparatus includes at least one reaction chamber and at least one electron beam source from which the electron beam is admitted into the reaction chamber through at least one pressure step zone. The electron beam source is structurally combined with the reaction chamber in such a manner that the axis of the pressure step stage runs parallel to the axis of the reaction chamber and that the electron beam can be rotationally deflected about this axis to traverse each surface element of a flow cross section of the reaction chamber running perpendicular to the axis at at least one position in the flow path.

Abstract: Apparatus for the manufacture of metal powder by atomization with noble gas or nitrogen, having an atomization tower, a gas recycling system, and a gas cleaning system is disclosed. The gas cleaning system is connected parallel to the atomization tower in order to shorten the start-up time without increasing the cost and complexity of the gas cleaning system.