A NEW APPROACH TO VARIABLE-PRESSURE CAKE FILTRATION

The widespread reliance on heuristics for the design and specification of particle/fluid separation devices has prompted a new, mechatronic based approach to dead-end pressure filtration. A computer driven expe rimental apparatus was used to facilitate proportionally controlled fi ltrations over a range of pressure/flow regimes whilst maintaining inh erent suspension properties. Preliminary results from constant flow ex periments using distilled water and aqueous suspensions of calcite are presented where the air pressure within the filter is controlled thro ugh a combination of flow and pressure transducers and an electronical ly adjusted pressure regulator. The effects of controller type, contro ller gain, sampling time and set point flow on system response are sho wn to illustrate what can be achieved using mechatronics. Predictions of constant flow filtration experiments are made using data from const ant pressure tests and reasonably good agreement is achieved. A simula tion, based on classical filtration and control theories, is also pres ented and shown to compare well with the filtrate flow responses obser ved from the filtration apparatus. (C) 1997 Elsevier Science Ltd. All rights reserved.