Patent GB-459332-A (GB)
Title: Improvements in centrifugal separating machines
IPC: B04B11/08
Filed: 1936-01-29
Abstract: 459,332. Centrifugal machines. AMERICAN CENTRIFUGAL CORPORATION, 70, Pine Street, New York, U.S.A. Jan. 29, 1936, No. 2658. Convention date, Jan. 30, 1935. [Class 23] A centrifugal separator with a rotary bowl on a vertical shaft has a movable scraper provided at one end with spaced cutting teeth to remove solids from the bowl wall, and at the other end with an extension to scrape solids from the vertical shaft. The separator is of the same general type as that described in Specification 453,651, and has a bowl with an imperforate cylindrical wall 6, a base 11 with central openings 10 for the discharge of solids, and an annular top plate 8 with channels 17, Fig. 6, for the discharge of liquids. A seepage plate 16 is arranged beneath the top plate 8 and has slots 18 through which the discharging liquid can reach the channels 17. The bowl rotates in the casing part 2 beneath the casing section 3 and above the section 1 which has an annular effluent trough 5. High and low speed motors 23, 24 are provided to rotate the bowl for separating and cleaning respectively. The sewage or other material to be dried is supplied through the feed pipe 32 and valve 33 to the twin feed pipes 35 which are telescoped with the upper ends of hollow shafts 30, and thereby communicate with the feed nozzles 40. Screw plugs 37 in the pipes 35 can be removed for the injection of steam, compressed air, or chemicals. The lower end of each hollow shaft 30 enters a hub portion 38, Figs. 13, 14 on a scraper 31; this hub portion forms the nozzle 40 and discharges material into the bowl in the direction of rotation. Each scraper has a thin curved body which directs the detached solids to the openings 10 in the base of the bowl. A rear extension 41 is carried into close proximity to the central shaft in the operative position of the scraper. The forward end of the scraper carries a vertical blade 47 which has cutting teeth 48 and cutting edges 50 between the teeth. The blade 47 and thickened front portion 42 form an abrupt shoulder 51 from which the severed sludge breaks. The scrapers can be swung outwards to operative position by the mechanism shown in Fig. 5. Arms 54 are secured to the upper ends of the hollow shafts 30 and carry pins 57 engaged in blocks sliding in transverse guides 60 on members 66 which slide in the fixed guides 64. The inner ends of the members 66 have sockets which are joined by a screw 65 engaging internal threads in a wheel 70. An electric motor 77 is employed to rotate the wheel 70 through worm gear, thus causing the screw 65 to move to the right or left to move the scrapers into their operative or inoperative positions. To prevent the scrapers overrunning the point at which power is cut off from the motor, a brake 78 is employed and is operated by a solenoid 80. Sludge is removed from the inner part of the seepage plate 16, to clear the entrance to the channels 17, by a movable blade 81, Fig. 6, with cutting edges ; this blade is secured to a vertical shaft 84 supported in the casing section 3 and operated by means of a solenoid 94. The pipe 32 through which material is fed into the bowl contains a valve 33 consisting of radial blades 103, Fig. 8, secured to end plates, thus forming pockets for the material. The size of the pocket discharging the material can be varied by means of a hinged plate 105 at the bottom of the valve. The position of this plate is controlled by the engagement of a cam 110 on the valve shaft with an arm 112 secured to the pivot 106 of the plate 105. The valve is rotated by a motor 115 through gearing 120, 121 so that a regular supply of material to the bowl is maintained. The speed of the valve may be varied by changing the pinion 120 ; the motor is carried by an adjustable support to permit this, and a pointer 122 moving over a scale 123 indicates the rate of supply of the material. The bowl wall has a frictional lining 52, Fig. 2, with spurs or projections 53 to prevent the separated solids from slipping during the cleaning operation.