Patent GB-1371227-A (GB)
Title: Self-cleaning centrifugal separator
IPC: B04B11/04
Filed: 1971-11-24
Abstract: 1371227 Centrifugal separators MACHINEFABRIEK REINEVELD NV and M BARAM 24 Nov 1971 [24 Nov 1970] 54633/71 Heading B2P A centrifugal separator, Fig. 1, for separating the components of a liquid-sludge mixture has a rotatable conical bowl 1 from which the sludge is discharged at the narrow end 3 through one or more openings 20 and the liquid is discharged at the wide end, e.g. through openings 19, the inner wall of the bowl being covered with flexible membrane sections 7 which are alternately inflated and deflated in a predetermined sequence by means of pressure fluid alternately supplied, and withdrawn between the inner wall of the bowl and the membrane sections, the latter being so constructed and arranged that when pressed away from the wall by the pressure fluid each section presents an inclined surface with its largest diameter nearer the narrow end of the bowl, whereby separated sludge is caused to travel towards this narrow end. The inner surface of the bowl is formed with annular grooves 6 of trianglar cross-section and the membrane sections 7 may be integrated into one single sleeve 8, as shown. The ends of the membrane sections are retained in annular recesses at the top of the grooves by expandable rings 22, Fig. 2. Alternatively, the sleeve may have parts between the membrane sections which are less flexible than the sections and form fluid-tight seals with the groove rims. Channels 9 open into the bottom of each groove and communicate with one or the other of valve-controlled conduits 10, 11 which are connected to annular fluid chambers 12, 13 respectively which in turn are supplied with control fluid through stationary pipes 14, 15 respectively inserted through hollow shaft 4 and controlled by supply valves. The conduits 10, 11 are furnished with control fluid evacuation valves 16, 17. The liquid-sludge mixture to be separated is fed through a stationary, pipe 18 projecting through a hollow shaft 5. In a modification, Fig. 4, there is only one fluid passage 25 and this communicates the single fluid supply chamber 13 with the valve 17 and with the first of the grooves 6. The grooves communicate with each other through passages 26. With this construction transport of the sludge is effected by intermittent closing and opening of the pipe 15 causing inflation of the membrane sections one afer the other in the manner of a wave which propels the sludge owards the discharge openings 20 in the bowl. When the supply of control fluid through the pipe, 15 is stopped, the fluid is ejected through the valve 17 and all the membrane sections will subside in the grooves 6. In a further modification, Fig. 3 (not shown), the bowl is constructed as an outer casing with an inner liner (23) in which the conduits (10, 11), channels (9) and grooves (6) are formed. The liner may be of the same material as the membrane sleeve (8) so that these parts can be welded along seams (24) at the top of the grooves. Instead of parallel annular grooves 6 a continuous helical groove may extend over the length of the bowl and is closed at one end and connected at the other end to the supply of control fluid. The membrane sections which may be parts of a single helical membrane cover each turn of the helix. Another arrangement may consist of a sleeve made of annular parts or of a single helical membrane and inflatable in a rolling wave fashion without grooves in the surrounding bowl wall or liner.