GB1476670A - Vortex clarifier - Google Patents

Abstract

1476670 Centrifugal separators QUEENS UNIVERSITY AT KINGSTON CANADA 10 Dec 1974 53348/74 Heading B2P A vortical separator for separating a fluid (as hereinafter defined) into heavy and light fractions comprises a separating annulus 24, Fig. 1, formed between an inner rotor 17 and an imperforate outer rotor 10 which are synchronously rotatable; a chamber communicating with the separating annulus and containing a set of impeller blades 20 for imparting angular momentum to the fluid and delivering it to the separating annulus along an axial flow path; and a plurality of stilling vanes 41 attached to the inner rotor 17 and extending radially towards the outer rotor to reduce the fluid flow cross-section, hence the turbulence, through the annulus and promote settling of the heavy fraction. The term "fluid" is defined as including particulate solids, liquids and gases and mixtures thereof which exhibit the properties of a fluid. The separator is constructed and operates substantially as the one described in Specification 1343729. As shown, however, bearings 42 permit shaft 16, inner rotor 17 and the vanes 41 to be rapidly stopped by a brake 44 while cylinder 10 continues to rotate with the fluid. A motor 49 drives, via a magnetic clutch 40 and a fluid coupling, a shaft 15 which is attached to a hub 28 and thus controls the rotation of outer rotor 10, conical portions 11, 12, vanes 20, 21 and hubs 28, 29. In operation, after an initial transient period in which the rotor 17 arid vanes 41 are accelerated to the rotational velocity of the rotor 10, the fluid rotates at the same velocity as the inner and outer walls of the annulus 24 and thus forms a forced vortex. The heavy fraction, e.g. sediment, is deposited against the outer wall of the annulus where it remains until the brake 44 is applied to cause relative movement between the vanes 41 and the rotor 10 thereby facilitating redispersion of the heavy fraction in the fluid. In Fig. 3 the vanes 142 are cut away towards the top and reduced in number at the top end by having some shorter vanes 143. Heavy fraction in the form of heavy inorganic sludges may be peeled off from the wall of the rotor 10 by the use of curved spikes 43 attached to the ends of some of the vanes. Instead of spikes, radially extending rods may be used or the vanes may be formed from moulded flexible plastics. In modifications: (a) the rotor 17 and the stilling vanes 1 may be locked to the hubs 28, 29 and the vanes may extend into the inlet area to merge with the vanes 20; (b) the drive may be applied to the rotor 17 rather than to the rotor 10 and vanes 41 may extend upwardly to take over the functioning of the vanes 20; (c) rotor 10 may be braked rather than rotor 17; (d) by mounting field coils inside casing 30 the rotor 10 could form the rotor of a motor and the shaft 15 would then be dispensed with.