Patent GB-1302044-A (GB)
IPC: B04B5/08
Filed: 1970-02-03
Abstract: 1302044 Gas centrifuges DORYOKURO KAKUNENRYO KAIHATSU JIGYODAN 3 Feb 1970 [10 April 1969] 4071/70 Heading B2P A gas mixture is separated into a light and a heavy fraction by introducing the mixture into one or more intermediate free spaces formed between two or more cylindrical concentric rotors which are rotated to subject the mixture to centrifugal forces and extracting the light and heavy fraction from the intermediate space(s). When separating isotopes of gas of large molecular weight, e.g. uranium hexafluoride, a light gas, e.g. helium, is preferably added to the feed flow to prevent slipping between the heavy gas and the inner rotor. The Fig. 3, a stationary centrifuge housing 1 contains rotors 10, 20 having concentric shafts 11, 21 and 12, 22. The shaft 12 is supported by a magnetic bearing 41, 42 and shafts 21, 22 are mounted in bearings 48. A highfrequency electric motor 80 drives the rotor 20 which in turn drives the rotor 10 at a higher speed in the same direction through gearing 49. The gas mixture to be separated is introduced through a pipe 8 and, after passing through the annular passage 9 is led into the intermediate space between the rotors 10 and 20, a ring 23 guiding the mixture along the rotor 10. Alternatively, the mixture is introduced through a passage extending partially through the shaft 12 and the rotor 10 and communicating with radial feed nozzles opening into the intermediate space Fig. 4 (not shown). The flow of the mixture is indicated by arrows 50, 51. Light and heavy fractions are discharged respectively through holes 26, 27 in the rotor 20 and pipes 2, 3 in the housing 1. Seals 4, 5 between the housing 1 and the rotor 20 may be supplied with a flow of light gas, e.g. helium, fed at 6 to prevent remixing of the light and heavy fractions. In Fig. 5, a rotor device 83 is fixed to the bottom of the rotor 10 and forms with a stator 84 a high-frequency motor for driving the rotor 10. The rotor 10 is supported by a magnetic bearing 43, 44 at its upper end and a pivot bearing 40' at its lower end. The second rotor is supported by a magnetic bearing 45, 46 and is driven by a high-frequency electric motor 80. The feed is introduced through a pipe 8 and an annular pipe 58 provided with slits or apertures 59. The light and heavy fractions are withdrawn through scoops 54, 55 which may consist of Pitot tubes. In Fig. 6 the centrifuge comprises three rotors 10, 20, 30 and the rotation of shaft 31 of rotor 30 driven by a motor 80 rotates the shafts 11, 21 of the rotors 10, 20 through a multiplication gear device 49. The gas mixture to be separated is fed in the space between the rotors 10 and 20 from which the heavy fraction is discharged through holes 27 and a scoop 65. The light fraction is led by a guide 66 into the space between the rotors 20 and 30 from which a light fraction is discharged through holes 37 and a pipe 3 and a heavy fraction through holes 36 and a pipe 2. The heavy fraction may be recirculated via a pump 68 with the feed mixture.  In Fig. 7, the gas mixture to be separated is fed to the first rotor 10 of the 3-rotor centrifuge through a hollow rotary shaft 19. The rotors 10, 20 have perforated end plates for the ejection of a fraction therethrough. The rotors may be made of reinforced plastics or high strength aluminium alloy containing copper and magnesium. Other series and/or parallel type centrifuge arrangements are described.