Patent GB-362843-A (GB)
Title: Improvements in or relating to centrifugal separators
IPC: B04B1/10
Filed: 1930-06-06
Abstract: 362,843. Centrifugal machines. FAWCETT, H. W., 3, Kent Road, Harrogate, Yorkshire. June 6, 1930, Nos. 17593 and 33914. [Class 23.] Density separators.--A centrifugal separator with peripheral sludge discharge apertures is provided with means which operate to permit the sludge to discharge, when its accumulation exceeds a given level. The spindle 1, Fig. 1, carries the bowl parts 2a, 2b secured together by a lock ring 3. The liquid for treatment is supplied through the pipe 6, and the liquid constituents pass out by the outlets 7, 8; apertures 9 for the discharge of the sludge are formed by nozzles 10 screwed into the casing part 2a. A valve member 11 is pivotally connected by links to each :nozzle 10. Opposite each nozzle is a tray 13 with an opening adapted to be engaged by the projection 11a on the valve 11. The tray is carried on one end of a pivoted lever 14, the other end of which carries a cup 15 with a leak hole. The lever is carried by a link 17 which can be raised and lowered by the linkage 18, 30 operated by the worm and cam gear shown in Fig. 2. An additional liquid, preferably liquid previously purified in the separator, is supplied through the axial conduit 20 to the distributing bowl 21 from which is passes through the pipes 22 to the vicinity of the nozzles 10. A branch 23 from each pipe 22 contains a screw plug 24 with an eccentric hole 25. During the operation of the machine the separated sludge collects in the nozzles 10, and the additional liquid, from the pipes 22 mixes with the purified liquid discharged from the outlet 7. As the sludge accumulates it obstructs the pipes 22, and the additional liquid is forced to pass through each pipe 23 into the cup 15 which then moves outwards under the action of centrifugal force. At the same time the tray 13 is moved inwards while it is moved slowly up and down by the linkage 18, so that when the opening 13a in the tray is engaged by the projection 11a, the valve 11 is forced off its seating. Sludge is then discharged through the opening 9 and fills the tray 13 ; the additional liquid meantime is leaking away through the hole 15a in the cup 15. Eventually the centrifugal force on the tray 13 overcomes that on the cup 15 and all the parts are restored to their original positions, the sludge being discharged from the tray over its upper edge. The action is repeated when the sludge again accumulates to the requisite depth in the nozzles. In a modification the valves 11 are opened by floats mounted on one arm of a lever, the other arm of which carries a counterweight. In another modification each nozzle 10 is connected to a corrugated conical distensible diaphragm 60 and is free to move radially in the casing wall. A piston 62 attached to the nozzle moves inside the cylinder 61, and the space 66 in the cylinder receives additional liquid from the space 64 to which it is carried by the pipes 22. The valve 11 is mounted on a bent arm 70 and is operated by the outward movement of the nozzle. As the sludge accumulates the nozzle 10 and the diaphragm 60 move outwards ; this compresses the liquid in the chambers 64, 66 and causes it to flow out through the hole 25. The lever 75 is tilted to disengage the catch 75b while the valve is moving away from its seating, and then to swing the valve downwards so that the sludge discharges into the sludge tray. When sufficient sludge has been discharged the nozzle and valve are returned to their normal positions. In another modification the valve is of the vane wheel type and the nozzle moves outwards against the action of bellows ; the outward movement is utilized to operate the valve. In the modification shown in Fig. 7 no additional liquid is necessary. A scraper 100 is mounted on the spindle 101 which is geared to a slidably mounted worm on the spindle 107. Normally the scraper is rotated through the gearing and the valve 11 is closed. As the sludge submerges the scraper 100 its motion is arrested, and the drive is transmitted to the worm 105 which operates the levers 112, 114 to move the valve 11. The sludge then discharges through the aperture 9 until the scraper 100 is free; a spring then returns the worm to its normal position and closes the valve so that the operation can be repeated. Specification 355,366 is referred to.