Patent GB-1341075-A (GB)
Title: Continuous flow centrifugation
IPC: B04B5/04
Filed: 1971-08-11
Abstract: 1341075 Centrifugal separation DAMON CORP 11 Aug 1971 [9 April 1971] 37617/71 Heading B2P In a continuous flow centrifugation process, a particulate sample to be separated into component particles of different densities is introduced in a liquid carrier through a top surface of the core 3 of a spinning centrifuge rotor 1 into a sample zone 18 in the housing of the rotor adjacent a zone 13A containing a density gradient solution so that the sample travels through the zone 18 and in so doing particles thereof separate therefrom and enter the density gradient zone 13A forming strata of different densities therein; the spent sample carrier liquid is removed through a bottom surface of the rotor core 3; a gradient liquid of greater density than the gradient solution is introduced through the top surface of the rotor core to the gradient zone 13A to displace the gradient solution with the strata therein radially inwards and the solution and strata are removed from the centrifuge core, while the rotor is spinning, through a passage 28 at the axis of the core, whereby the sample strata are recovered sequentially, with the least dense stratum being recovered first. A motor drive is connected to a socket 8 in the rotor. The gradient solution and the gradient liquid are introduced through a first circular groove 10 which extends from the top surface of the rotor housing 2 into the core 3 and communicates with radial passageways 11 terminating at the ends of fins 12a, 12b, 12c, 22 extending into the density gradient zone 13A. The sample and its carrier liquid are introduced into a second circular groove 15 which communicates with a passage 16 terminating at the periphery of the rotor core 3. The sample circulates through openings in the fins 12a, 12b, 12c. The fin 22 is imperforate and by pass of the sample around the fin is prevented by circular plates 23, 24 fixed to the rotor housing 2 and to the top and bottom surfaces of the fin. The spent sample carrier liquid passes through a drain passage 19, Fig. 6, which extends through the rotor core 3, the plate 24 and the bottom surface of the rotor housing 2 to an outlet 20. The gradient solution with the separated strata therein is removed through passages 26 in the core 3 which communicate with the axial passage 28 extending through a spring-loaded rotary sealing arrangement 44, 45, 46, 30a, 31, 30, 32 to a sample removal tube 29. The rotary seal housing 33 is movable into and out of the rotor 1 by means of a pivotable lever 36 which bears on a main seal housing 34. The latter is fixed to the centrifuge housing (not shown) by means of a shelf 42 and a safety disc 43. The shelf 42 is provided with openings 10a, 15a to accommodate filling tubes which can extend into the grooves 10, 15. Sample recovery is effected by a pump 50 which reduces the pressure in a collection chamber 51, tube 29, and passages 28, 26 when a valve 52 is opened and valves 53, 54 are closed. After the desired sample portion is collected in chamber 51, valve 52 is closed and valves 53, 54 opened so that the sample portion is recovered through a conduit 55. In a modification, the rotor is segmented by closing the openings 21 in fins 12a, 12b and 12c and additional sample inlet passages and drains are provided for each rotor segment so that the sample travels only through approximately 90 through the rotor instead of 360 as in the above-described embodiment.