Patent GB-1440051-A (GB)
Title: Centrifuge rotor
IPC: B04B7/08
Filed: 1974-01-31
Abstract: 1440051 Centrifugal separator BECKMAN INSTRUMENTS INC 31 Jan 1974 [16 April 1973] 04436/74 Heading B2P In a centrifuge rotor 1 having a sidewall 4 enclosing a bowl-shaped chamber 3 which is provided with a cover 2 secured by means such as threads 5, 7 to the sidewall 4, a resiliently deformable lip 47 extends inwardly from the sidewall in overhanging relationship with the chamber and has an upper surface 47b engaging the lower surface 46 of the cover so that during centrifugation the lip will follow any outward axial movement of the cover relatively to the sidewall and will maintain sealing contact with the cover. The rotor is of the type used for zonal centrifugation in which a sample of minute particulate matter, e.g. tissue cells or cell particles, in a carrier liquid is fed into the central region of the rotor chamber which contains a density gradient solution. The chamber is divided into sector-shaped compartments by means of angularly spaced radial baffles 11 which engage in longitudinal slots formed in a core member 9 which has legs 31 abutting the bottom 32 of the chamber. A tube 13 is screwed into a cavity 16 formed in the core member 9 and is provided with a central passage 27 which communicates, via passages 28, 29 in the core member, with the chamber compartments. Passages 19 formed as slots in the outer surface of the tube 13 communicate with an opening 16a in the core member which in turn communicates via passages 22 in the core member with passages 23 which extend through the baffles 11 and communicate, via openings 24 in cut away portions 26 of the baffles, with the upper portion of the chamber. A cup 34 is sealingly attached to the cover 2 and has openings in communication with the passages 19 and 27. In operation, the rotor is first rotated at relatively low speed. A rotatable liquid delivery means is inserted into the cup 34 and pumps a density gradient solution through the passages 19, 22 and 23 into the chamber compartments causing it to form concentric annular zones of constant density solution. A sample to be centrifuged is then pumped through the passages 27, 28 and 29 into the centre portion of the chamber. The sample is washed clear of the passages by pumping through a low density liquid. The liquid delivery means is then removed, the cup 34 is closed by a cap and the rotor rotated at high speed. When centrifugation has been completed the rotor is decelerated to relatively low speed. The contents are emptied through the liquid delivery means bv pumping a high density fluid to the outer wall of the rotor chamber through passages 19, 22 and 23 to force the gradient solution and the sample, dispersed in the annular gradient zones, towards the core member 9 and thence through the passages 29, 28 and 27 through the delivery means. During centrifuging rotation of the rotor the resulting axial hydraulic forces within the chamber cause the cover 2 to move upwardly away from the rotor. At the same time these forces act on the lip 47 to deflect it upwardly so that its upper surface is kept in contact with an O-ring seal 48 positioned in an annular slot 49 in the lower surface of the cover.