GB1451532A - Centrifuges - Google Patents

Abstract

1451532 Centrifugal separator PELLERIN ZENITH AB 12 Feb 1974 [13 Feb 1973] 06346/ 74 Heading B2P A centrifuge comprises a shaft 1 supported by bearings 11 at its opposed ends and driven by a motor (not shown); a cylindrical drum 2 having end walls 3, 4 and coaxial with the shaft; two pairs of channels 5, 6 and 7, 8 provided in the shaft with their mouths at opposite ends of the drum and establishing communication between the interior of the drum and outlet conduits at the two ends of the shaft which are adapted to supply untreated feedstock and to discharge treated material, respectively; at least one sationary disc 9 located between the mouths of one pair of channels and extending at right angles to the shaft and having a radius smaller than that of the drum; and an annular piston 10 coaxial with the shaft and having a radius substantially equal to that of the drum, the piston being movable along the shaft from an extreme position at one end of the drum to an extreme position at the other end of the drum. When separating phosphatide sludge from fatty oil treated with phosphoric acid, the oil/sludge mixture is fed through channel 6. The sludge is centrifugally separated against the wall of the drum and, if of low viscosity, moves laterally therealong and through the annular gap between the disc 9 and the drum wall and discharges through channel 5. The oil is drawn off through channel 7. When the centrifuge is to be stopped and emptied, the feed of oil/sludge mixture is interrupted and water is supplied through channel 6. The water becomes interposed between the oil and sludge in the drum and expels the oil through channel 7. Water is then supplied through channel 8 to move the piston 10 towards the disc 9, Fig. 4, and force the mixture of sludge and water through the channel 5. The same procedure may be used to discharge highly viscous sludge which does not by itself move through the gap between the disc 9 and the drum 2. When the piston reaches its end position in which it bears against the disc 9 the supply of water through channel 8 is interrupted. To put the centrifuge back into operation, oil/sludge mixture is first supplied through the channel 5 to move the piston 10 to the right past the mouth of channel 6, the supply being then switched over to channel 6 to return the piston to its original position. The supply of water to dislodge the oil from the drum may be dispensed with and in this case the oil contained in the drum at the closure of channel 6 is discharged with the sludge through channel 5. In another embodiment, especially for treating oils with highly viscous sludge, a further disc is placed between the mouths of the channels 7 and 8 and the piston is movable between the discs.