Patent GB-1379376-A (GB)
Title: Automatic centrifuge drum for clarifying liquids
IPC: B04B1/14
Filed: 1973-03-27
Abstract: 1379376 Centrifugal separator WESTFALIA SEPARATOR AG 27 March 1973 [27 April 1972] 14549/73 Heading B2P  A liquid centrifuge clarifier drum is provided with a main sleeve valve 1 for periodically opening discharge orifices 2 for separated solids, a first control annular chamber 4 located in proximity to the drum axis and provided at its side adjacent the drum axis with at least one passage 5 for the supply of a sensing liquid and at its radially outermost part with one or more passages 6, 6a leading into the solids receiving part 3 of the drum, a pulse generator 7 in the chamber 4 responsive to the displacement of the free level of the sensing liquid in the chamber 4, and an auxiliary sleeve valve 11 for opening and closing discharge orifices 10, 12 for the liquid portion of the contents remaining in the drum after a centrifuging cycle, the valve 11 being provided at one side with circumferentially disposed compression springs 13 and at its other side with a second control chamber 15 which communicates through one or more passages with a central annular groove 17 separated from the first control chamber 4 by an annular wall 18 whose internal diameter is larger than that of the top surface 19 of the chamber 4 and that of the bottom surface 20 of the groove and smaller than the extent to which the pulse generator 7 extends into the chamber 4. In operation, liquid to be clarified is supplied to the drum through a feed pipe 21 via a line 26 leaving a valve 25. The separated solids collect in the space 3 whilst the clarified liquid flows from the interior of separating plates 8 out through passages 22 and over the internal edge of an annular plate 23 into a paring chamber 24 and thence through a line 28 having a valve 27 or is discharged freely from the drum. The chamber 4 is supplied with sensing liquid, which may be tapped off the calrified liquid, through the passage or passages 5. The sensing liquid is directed through the passages 6, 6a into the solids space 3. The passages 10 are kept closed by the spring biased valve 11. As soon as the solids layer in the space 3 closes the ports of the passages 6a, the free level of the sensing liquid in chamber 4 moves inwards and first reaches the pulse generator 7 which supplies a pulse to a control unit (not shown). This pulse sets a timer relay into operation and, after a set time period, the valve 1 is placed in the open position. The pulse also shuts the valves 25, 27 at an appropriate moment. Sensing liquid continues to flow to the chamber 4 and passes over the internal edge of wall 18 into the groove 17 and through a passage 16 into chamber 15. As soon as the force exerted by the liquid in chamber 15 becomes greater than the force of the springs 13, the valve 11 is lifted from its seat and the major part of the liquid in the central part of the drum is discharged through the passages 10 and 12. After the set time period, the control unit opens the valve 1 for the discharge of solids. In so doing, the ports of passages 6a are opened again and the sensing liquid flows back into the space 3. After the closing of the valve 1 and the opening of the valves 25 and 27 the next centrifuging cycle commences.