Patent ID: 7763168

Claim:
A vertical spindle batch-type centrifuge for processing liquid/solid slurries in discrete batches, comprising: a stationary casing; a rotary, perforated, open top basket, suspended within said casing, on whose inner peripheral wall a cylindrical batch of slurry is deposited, in use, as the basket rotates with respect to the casing, so as to retain the solids within the basket and to separate the liquid by filtration via the basket perforations; a laser arrangement fixed with respect to said casing and positioned to direct one of a continuous stream of pulses and a beam of coherent light energy towards said inner peripheral wall of the basket; a computing device coupled to said laser arrangement and adapted to calculate continuously over time or at repeated intervals over time a depth and a rate of change of a depth, of the cylindrical batch of slurry contained within the basket, from a series of repeated laser measurements made with said laser arrangement throughout a complete operating cycle of each cylindrical batch of slurry from commencement of slurry feed to discharge of solids; and a feed valve that is opened to deposit the cylindrical batch of slurry in the suspended rotary, perforated, open top basket and that is closed in response to the computing device.