Patent GB-1180537-A (GB)
Title: Liquid Centrifuge for Large-Scale Virus Separation
IPC: B04B5/04
Filed: 1968-07-22
Abstract: 1,180,537. Centrifugal separator. UNITED STATES ATOMIC ENERGY COMMISSION. 22 July, 1968 [1 Aug., 1967], No. 34909/68. Heading B2P. A continuous-flow centrifuge for the largescale separation of virus in a liquid medium comprises a vertical rotor bowl 1, Fig. 2, closed by end caps 18, 19 provided with axial passageways. A core member 11-13 defines with the bowl 1 a number of sector-shaped chambers 17 for receiving a density gradientforming solution and virus-containing liquid. Each end cap defines with the core member radial passageways 15 which extend between the chambers 17 and the axial passageway in the respective end cap. The rotor is supported by tubular shafts 3, 6 providing liquid passageways communicating with the axial passageways in the end caps 18, 19. Tubular elements 38, 47, Fig. 4, sealingly engage the ends of the shafts 3, 6 for transferring liquid to and from the shafts. An air-driven turbine is rigidly connected to the upper shaft 3 and provides axial support for the bowl 1. The shafts 3, 6 are each engaged by damping and bearing means providing damped radial support to each shaft. The rotor bowl is enclosed in a housing 2 which serve as a crash shield and vacuum enclosure for the bowl. As shown in Fig. 4, the lower shaft 6 is supported radially by a journal bearing 26 mounted within a spherical bearing 27 in turn mounted within a radially movable damper disc 28 between which and a sealed housing 31 is disposed a silicone rubber O-ring 30 providing a resilient radial support for the disc 28. A spring 34 urges the disc 28 towards a stationary damper plate 33 which is separated from the disc 28 by a silicone rubber pad 32. Lubricating oil is circulated to the lower end of bearing 26 and the exterior of disc 28. Leakage oil collects in a conical reservoir 35 formed by the plate 33. A lip-seal 36 prevents downward leakage of oil. The lower end of shaft 6 is provided with a steel cap 37 forming a rotary seal with the tubular stationary element 38 which is made of P.T.F.E. impregnated with iron oxide and supported in a spring biased tubular holder 39 mounted in a housing 41 having a tubular extension 9. Coolant is circulated about the element 38 and the holder 39. The upper rotor shaft 3 passes through a damper and bearing assembly similar to the assembly 26-34 of the lower shaft 6 and is rigidly joined to the turbine wheel. The top end of the shaft 3, Fig. 5 (not shown), extends above the turbine wheel (45) and is connected to a tubular extension (8) through a sealing assembly (46-50) similar to the assembly (36-41) for the shaft 6. The housing 2 has a longitudinally extending side opening normally closed by a door 51, Figs. 6, 7, hinged at 52 and sealingly engaging a flange 54. Channel-shaped members 56 hinged at 57 serve to lock the flange 54 and door 51 together. U-shaped bars 59 engaging in L-shaped brackets 58 on the members 56 serve to keep the latter in their locking position. In operation, the rotor is filled with a density in gradient-forming solution and gradually accelerated to speed so that annular vertical zones of different densities develop forming a radial density gradient. Virus-containing liquid is then introduced to the radially innermost face of the density gradient. Both the density gradient-forming solution and the virus-containing liquid are introduced through either the tubular extension (8) or 9 depending on the orientation of the core member 11-13 which is tapered, the smaller diameter end of the core member being normally adjacent the inlet end of the rotor. As shown in Fig. 2, the inlet is through the tubular extension 8 and the hollow shaft 3. At the end of a run, the flow of viruscontaining liquid is stopped and the rotor may be allowed to coast to a standstill whereupon the density gradient becomes reoriented so that zones of varying densities assume a horizontal position. The gradient liquid containing the separated virus is then removed by gravity flow through the passageways 15, lower shaft 6 and tubular extension 9. The removal may be speeded up by supplying pressurized air through the tubular shaft 3. Alternatively, the rotor bowl is allowed to continue its rotation and a dense displacing solution is introduced in the rotor through the tubular extension 9 and displaces the less dense gradient solution containing the separated virus outwardly through the upper tubular shaft 3. After gradient solution has been removed, the displacing solution is drained from the rotor through the tubular extension 9.