| 摘要 |
<p>1290550 Gravity - separation apparatus EASTMAN KODAK CO 13 Nov 1969 [15 Nov 1968] 55642/69 Heading B1D [Also in Division Gl] Clear liquid 12 is automatically withdrawn from a vessel 10 where it is present between scum (or foam) 18 and a sludge 14 of precipitated floc, by means of a suction pipe 20 the mouth 26 of which is associated with a sensor 28 of scum and of floc 16 suspended in clear liquid, this sensor also controlling a valve 24 in the pipe 20 and a servo drive 22 which lowers the pipe vertically. Mounted in tube 20 above sensor 28, there is a sensor 46 for clear liquid, e.g. a pair of contacts which are electrically short-circuited when in an electrically conductive liquid. With the mouth 26 positioned above vessel 10, the power supply 48 is energized by closing its switch, thereby applying a signal to drive servo 22 to move pipe 20 downwards. As the mouth 26 drops into the scum 18, the sensor 28 produces an output signal which makes the NOT circuit 38 produce no output signal thereby allowing valve 24 to remain closed. Valve 24 opens when sensor 28 first enters clear liquid 12; and suction commences. The servo 22 continuous to lower pipe 20 until sensor 46 dips into the clear liquid 12, whereupon sensor 46 energizes self-holding relay 42 so that switch 40 is actuated and circuit 38 now operates servo 22. If sensor 28 does not detect floc, valve 24 remains open and, as the clear liquid is drawn off through pipe 20, the servo 22 lowers the mouth towards the sludge 14. Eventually, when all the floc has settled as sludge, the clear liquid 12 will be completely drawn off, leaving within vessel 10 only the scum 18 and the sludge 14. Sensor 28 may detect the presence of scum or suspended floc by reflection of light from a lamp, periodically excited by an electrical pulsing device, onto a ganged photocells (see Division G1). Alternatively, the sensor may be a gallium arsenide radiation emitter and excitation circuit of the "Emitting Diode" type.</p> |
