Patent GB-1075835-A (GB)
Title: Centrifuge
IPC: B04B1/20
Filed: 1965-07-28
Abstract: 1,075,835. Centrifugal separators. BIRD MACHINE CO. July 28, 1965 [Oct. 21, 1964], No. 32309/65. Heading B2P. In a centrifugal separator comprising a rotatable bowl 24, Fig. 1, into which a mixture of liquid and finely divided solids is fed through an inlet conduit 50 and from which the separated solid particles are discharged by means of a screw conveyer 40, rotating at a speed different from that of the bowl, via an end opening into a chamber 23, while a layer of separated liquid is retained in the bowl inwardly radially of, and in contact with, the moving solid particles, a liquid discharge conduit 73, 75, Fig. 2, has a skimming opening 77 which is adjustable, by means operable while the separator is running, through a range of radial positions including a position radially inwardly of the bowl wall and a position at least as far from the axis of rotation of the bowl as the maximum radial distance the internal peripheral surface of the bowl is from the axis of rotation of the bowl. The conduit being thereby adapted to skim dry at least an axially extending portion of the bowl while the separtor is running. The bowl 24 is provided with an annular gutter 39 into which the liquid discharges via openings 36 in the bowl head 35, the internal diameter of the gutter being slightly greater than that of the bowl so that all of the liquid reaching the left hand end of the bowl discharges into the gutter. Pipe sections 65, 67 extend from both sides of a recessed portion 62 of the separator casing 20, the outer end of section 65 being closed and having a downwardly extending outlet 71 for the liquid. The liquid discharge conduit, Fig. 6 (not shown) has one end of its hollow cylindrical portion 73 slidingly disposed into pipe section 65 and its skimmer portion 75 extending upwardly so that the skimmer opening 77 is located inside the gutter 39 when the conduit is slid far enough to the right. The skimmer has narrow-edged, liquid-skimming blade portions 78, 79. Adjustment of the conduit 73, 75 is controlled by means of a screw 87 carrying a handle 90 and threaded through a cap 85 mounted on one end of an internally recessed shaft 80 bolted to the closed end 74, Figs. 3 and 5 (not shown), of the portion 73 of the liquid discharge conduit. Shaft 80 slides in pipe section 67 on the end of which is carried a clamp 95 which may be tightened or loosened to respectively restrain or permit rotation of the screw 87. A nut 101 threaded on screw 87 cooperates with a scale 100 mounted on the clamp 95 to indicate the radial penetration of the skimming opening 77 into the gutter 39. Rotation of shaft 80 is prevented by a pin 114 removably held in a sleeve 112 and engaging in a slot 104 in the outer surface of shaft 80, the pin also cooperating with stop surfaces 107, 110 to limit the translational movement of the shaft. The gutter and bowl can be skimmed dry by moving the skimmer to its extreme right hand position. Wash water can then be introduced through the feed conduit 50 after the solids have been discharged, the bowl washed out and then skimmed dry before the separator is shut down. The skimmer 75 may be tilted out of the way of the separator proper, Fig. 4 (not shown) to enable the latter to be lifted out of the casing 20. To do this, the skimmer is adjusted to its radially inwardmost position, and after upper part 20a of the casing is removed, the pin 114 is lifted to permit rotation of shaft 80. The entire liquid discharge conduit assembly is then rotated towards the end of the casing. In another embodiment, Figs. 9-12 (not shown), a liquid discharge conduit 160 is mounted with a shaft portion 167 being journaled in a block 170 fixed in an opening 151 in an end wall 61a of the casing and a cylindrical portion 161 engaging in an opening 156 in an internal partition 152 parallel to end wall 61a, whereby the conduit may be pivoted parallel to the plane of end wall 61a and the position of the skimmer opening 163 extending into the gutter altered. A lever 175 mounted on the overhang of the shaft portion 167 is connected to an adjusting screw 185 which can be rotated by a handle 187 to alter the radial position of the skimmer opening 163 in the gutter. A stationary effluent pipe 195 is journalled in the open end of the cylindrical portion 161. In any of the embodiments described, a splash pan 200, Figs. 13 and 14 (not shown), may be provided below the gutter to collect any liquid splashing out of the gutter, the splashed liquid being returned to the gutter by means of one or more scoops 205, 206 located on the outer surface of the bowl and directing the liquid via passages 208, 209 in the bowl head 35a.