Patent GB-1004013-A (GB)
Title: A process and apparatus for the separation of a gas mixture
IPC: B03C1/253
Filed: 1963-11-27
Abstract: 1,004,013. Centrifugal separators. LA SOUDURE ELECTRIQUE AUTOGENE PROCEDES ARCOS. Nov. 27, 1963 [Nov. 28, 1962], No. 46819/63. Heading B2P. [Also in Division H2] Gases of different densities are separated from a mixture thereof by feeding the mixture under pressure into, and along the axis of, a chamber whose side wall is shaped as a surface of revolution, ionizing the gases by means of an ionizing field, applying to the ionized gas stream outside of the ionizing field a rotating magnetic field whereby the ionized gases are separated by centrifugal action into coaxial layers, and separately collecting the layers. In Fig. 1 the mixture of gases fed axiallly through a tube 3 is ionized by the electric field produced by an arc striking between electrodes 2 and 7 connected to an A.C. or D.C. generator 5. The ionized mixture 5 then passes successively through guides 13, 13<SP>1</SP>, 13<SP>11</SP> where it is subjected to rotating magnetic fields produced by coils 10, 10<SP>1</SP>, 10<SP>11</SP> fed with polyphase, e.g. 2-phase, A.C. from a source 11. As a result of centrifugation the gases separate into different layers. The heaviest layers are removed successively through passages 14, 14<SP>1</SP>, 14<SP>11</SP>, manifolds 15, 15<SP>1</SP>, 15<SP>11</SP> and conduits 17, 17<SP>1</SP>, 17<SP>11</SP> into containers 18, 19 while the lightest central portion of the mixture is led into a container 20 by a conduit 21. In an arrangement for producing the rotating magnetic field comprising two pairs of diametrically opposed coils at 90 degrees to each other, the coils of each pair are fed in series at the start with alternating current from a two-phase alternator. Once rotation of the field is established, it is maintained by feeding all four coils from one only of the two phases of the alternator by the operation of a double-pole switch. In a modification, the start of rotation is obtained by feeding the coils, as before, from a 2-phase alternator but rotation is maintained, on operation of a six-pole switch, by means of singlephase A.C. supplied from a different alternator driven by a variable speed electric motor which permits increasing the rotating speed of the magnetic field and hence the centrifugal action, this being necessary when separating gases having nearly equal masses. Alternatively, the single phase alternator may be replaced by an electronic generator ; the speed of the rotating magnetic field may also be changed by changing the number of magnetic poles in the circuit. In Fig. 2 the ionization of the gas mixture is obtained in two or more stages by currents induced by magnetic fields resulting from the passage of high frequency A.C. from a generator 24, through coils 22, 22<SP>1</SP> which surround quartz tubes 23, 23<SP>1</SP>. A starting electrode, e.g. of graphite or tungsten, can be temporarily introduced into coil 22. Heating of this electrode by the induced high frequency current passing through it assists in creating the ionized plasma which is then brought to high temperature and kept ionized by the induced current from the magnetic field. In Fig. 5, the ionization of ionized plasma created in the arc 8 striking between electrodes 2 and 7 is reinforced by an ionizing magnetic field created by a high frequency A.C. passing in a winding 22 surrounding the arc 8. A consumable electrode may be used which by its fusion and its evaporation in the arc supplies to the gas stream one of the ingredients or elements which, after centrifugal separation, can react with another element. Gases, solids or liquids may be brought into contact with the ionized gas either along the gas stream axis or at its periphery.