Patent GB-1104444-A (GB)
Title: Sludge centrifuge
IPC: B04B11/02
Filed: 1965-03-15
Abstract: 1,104,444. Centrifugal separators. K. LURZ. 15 March, 1965, No. 10868/65. Heading B2P. In a sludge centrifuge, Fig. 1, having separate settling and sludge discharge chambers 22, 3 defined in the centrifuge drum 2 and communicating with each other only in the region that is occupied by sludge in operation, pusher vanes 21 are provided within the drum for urging separated sludge towards the discharge chamber 3 and are adapted to rotate at a lower speed than the drum. Sludge discharge means 13 are adjustably mounted in the discharge chamber 3. An overflow weir 50 determines the maximum radial depth of the suspension in the settling chamber 22. The vanes 21 are connected to the wall 51 of the chamber 3. The latter carries a shaft 5 which is rotated through belt and pulley means by an electric motor 7. The drum 2 has a tubular shaft 6 which is rotated from the shaft 5 by belt and pulley means 8, 35. The chamber 3 is provided with peripheral scoop-like apertures (4), Fig. 2 (not shown) which serve to scrape off the sludge from the chamber 22 and direct it into the chamber 3. The discharge means 13 is in the form of a tubular scraping element via which the scraped sludge is directed into a tube 10 from which it is discharged by a worm 11. The scraping element 13 is automatically radially adjustable by means of a hydraulic device 37 actuated by pivotal movements of an idler pulley 36 caused by changes, due to variations of load, in the tension of the belt between motor pulley 8 and drum pulley 35. The suspension to be clarified is introduced at 14 in a zone 16 separated from the rest of the settling chamber 22 by a disc 17 mounted on the vanes 21. The clarified liquid is discharged over the weir 50 into a channel 9. In another embodiment, Fig. 3, the sludge discharge chamber 3' is defined by a plate 41 fastened by supports 40 to the drum 2' to rotate therewith while the vanes 21' in this case are rotated separately. A baffle 23 secured by supports 39 to the plate 41 prevents unclarified suspension from passing directly into the space 25 but allows clarified liquid to do via perforations 24. The sludge discharge means is in the form of a pivotally mounted drum 26 having a scraping portion 13' and mounted eccentrically to the drum axis so as to be swung into its operative or inoperative position in response to the power required to maintain the differential speed between the vanes 21' and the drum 2' or to the pressure exerted on a measuring device 38, e.g. a pressure or a strain gauge, installed in the settling chamber. The sludge is discharged from the drum 26 by a worm 11' on a shaft 28 for the drum 2'. In a further embodiment, Fig. 5, settling of the sludge in a chamber 22" is accelerated by conical discs 31 mounted on a drum 30 carried by a plate 17" which also carries vanes 21" and is rotated by a tubular shaft 5" through which the suspension to be clarified is fed. The clarified liquid passes into the interior of the drum 30 via orifices 32. The interior of the drum is divided by annular members 42 into compartments from which the clarified liquid is discharged into a conduit 33 through tubes 15" having their inlet orifices located on a parabola corresponding to the surface 34 of the clarified liquid in operation. The pressure measuring device in the settling chamber 22" in this case may be installed as at 38" on the vanes 21".