GB1441487A - Self-purging centrifuges - Google Patents

Abstract

1441487 Centrifugal separator DONALDSON CO INC 10 June 1974 [20 June 1973] 25590/74 Heading B2P A self-purging centrifuge comprises a drum 10, 12, 14 rotatable about a vertical axis, and having means for e.g. a pipe 40, for introducing into the drum a fluid containing solid particles, e.g. machine tool coolant carrying metal clips means 42 for discharging clarified fluid after separation of the particles, and means for discharging the separated particles; a rotor 18, 20 mounted inside the drum for coaxial but independent rotation therewith, the periphery of the rotor being spaced apart from the interior surface of the drum where particles separated by centrifugal force are deposited; and means, e.g. an air brake 56, to provide an abrupt change in the relative angular velocity between the interior surface of the drum and the periphery of the rotor such that the deposited particles are removed from the said surface under the influence of the resulting change in motion of fluid in the drum, and are thereby re-suspended in the fluid to be subsequently discharged therewith from the drum. The rotor consists of vanes 20 bolted to a pin assembly 18 secured to a shaft 16 which is driven by a motor through belts 36 and a pulley 38. The drum rotates on a bearing 28 mounted in a cover 24 of a surrounding housing 22 and on a bearing 30 mounted in the bottom member 14 of the drum. The rotor rotates in bearings 32 and 34 mounted in the top well 12 of the drum and in bottom portion 26 of the housing respectively. The fluid with suspended particles is fed through the pipe 40 into the rotor and is thrown by the latter towards the drum side wall 10, the fluid rotating with the rotor and the rotating fluid in turn causing rotation of the drum, clarified fluid is discharged via openings 42 in the top wall of the drum and is directed by anti-splash baffles 52, 54 downwardly onto a chamber 44 for removal through an outlet pipe 70. During the purge cycle the brake 56 is actuated and causes a shoe 58 to engage a projection 60 on the drum to slow down or stop the drum. When this is done, the rotating vanes 20 of the rotor disrupt the fluid and the deposited particles become re-suspended in the fluid. As the purge cycle continues the fluid and the re-suspended particles flow inwardly and downwardly along the upper surface 72 of a triangular-shaped annular baffle 62 secured at the bottom of the drum side wall 10, then outwardly through openings in the side wall and openings 27 in the bottom portion of the housing 22, and finally through an outlet 66 in a lower well of the housing. A ring 50 having louvred openings therein is placed over the inside of the openings 42 to prevent escape of fluid and suspended particles through the openings during the purge cycle. During the latter the feed of fluid and particles through the inlet pipe 40 may be shut off or reduced. Instead of the drum, the rotor may be braked.