Patent GB-1207500-A (GB)
Title: Multiple chamber centrifugal separator and rotor therefor
IPC: B04B1/12
Filed: 1967-12-15
Abstract: 1,207,500. Centrifugal separators. DORROLIVER Inc. 15 Dec., 1967 [21 Dec., 1966], No. 57053/67. Heading B2P. In a centrifuge rotor 12, Fig. 1, comprising primary and secondary separating chambers 52, 54, Fig. 3, to which a multi-fraction material, to be fractionated in each chamber by means of axially spaced separating discs 56, 86 into at least two components, is fed via passages 35 and a feedwell 34, Fig. 1, the discs 56 of the primary chamber 52 are provided with a first series of openings 64 to distribute the feed material onto the discs so that at least one of the fractions of the feed material is separated while the remainder of the material is transferred to the secondary chamber 54 by a second series of openings 88 in the separating discs 56, 86 of the primary and secondary chambers 52, 54 so that a further separation of the feed material is effected in the secondary chamber. The feed material may consist of a light liquid-heavy liquid-solids mixture. The feedwell 34 is formed within a tapered shell 28 having vanes 30 which impart a rotary motion to the feed mixture to deliver it downwardly and outwardly to channels 46 defined by vanes (not shown) extending radially from a feed impeller 44 integral with the shell 28 and seated on the rotor hub 32. The channels 46 communicate via annularly spaced passages 62 with passages 66 formed by the sets of openings 64 in the separating discs 56 of the chamber 52. In the latter, primary separation of the mixture results in a light liquid fraction and a heavy liquid-solids mixture fraction. The light liquid moves inwardly to discharge into channels 68, Fig. 2, between axially extending vanes 70 in chamber 72 and out of the rotor over a weir 74. The heavy liquid-solids mixture fraction moves outwardly until intercepted by passages 76 formed by the sets of openings 88 in the separating discs 56, 86 of the chambers 52, 54. The mixture is thus transferred through the passages 76 into the chamber 54 where secondary separation takes places into a heavy liquid fraction and a solids fraction. The heavy liquid moves inwardly and is discharged through tubes 90 which are slotted at 92 along of the portion of their lengths lying in the chamber 54 and which communicate with conduits 96 from which the heavy liquid discharges over weir 98. The solids move outwardly of the discs 86 into a compacting zone 78 and are discharged from the rotor by means of nozzles 112. Any light liquid entrained with the heavy liquid-solids mixture into the chamber 54 will travel inwardly towards the discharge channels 68; if any of the light liquid is entrained with the heavy liquid in the tubes 90 it will be released through weep holes 100 at the upper ends of the tubes. A phase divider 78 is provided between the chambers 52, 54 to prevent .any liquid-solids mixture from entering the zone 77 from the chamber 52. The divider 78 forms with the foot portion 82 of the impeller 44 an orifice 84 which will allow passage of only heavy solid particles into the zone 77. A portion of the solids discharged from the rotor may be recycled into the rotor through a conduit 114, with or without wash liquid introduced through a conduit 118, via an impeller 126, 128 and return tubes 130 opening into the compacting zone 77. More than two separating chambers may be provided into the rotor for fractionating feed material comprising more than three fractions.