| 摘要 |
491,623. Aerating sewage etc.; gravityseparation apparatus. McILLERON, R. C. Aug. 11, 1937, No. 22120. Convention date, May 14. [Class 111] Solids and liquids in sewage and polluted water are separated by first aerating the sewage liquid or water to effect saturation or partial saturation with air at a predetermined pressure, and then effecting a drop in the pressure such that air is evolved to produce movement of the solids upwardly relatively to the liquid, the separated solids and liquid then being drawn off from one another. The sewage is fed from a preliminary settlement tank 5 into a launder 4 communicating by a pipe 2 cock 12 and Venturi tube 8 with a pressure or aerating vessel 1, this vessel being situated at a sufficient depth to give the desired pressure to the sewage liquid. The Venturi tube is provided with air inlets 9 through which air is drawn into the liquid the supply of air being controlled by a cock 11. The chamber 1 is provided with a motor driven impeller 14 by which the liquid is drawn up a tube 18 and flung at high velocity against the sides of the vessel, thus becoming saturated with air. The air-saturated liquid passes upwardly through the outflow pipe 3, which is of less cross-section than the pipe 2, at such a velocity that the solids are carried therewith up the pipe to a settling tank 7. As the liquid rises in the pipe some of the air dissolved therein is freed due to the reduction in pressure and ascends to the surface in the form of small bubbles carrying with it the floatable solid particles. These accumulate in a sludge compartment 25 of the tank 7 and are run off at intervals through a pipe 26, the clarified effluent and heavy solids being drawn off from a chamber 22 and 28 respectively. In a modification the pressure chamber, instead of being provided with an impeller, is provided with a series of plates over which the liquid flows to expose a large surface to the air and in another a circulating pump is provided by which the liquid is caused to flow over frusto-conical baffles for the same purpose. Instead of being produced statically the pressure on the liquid in the chamber may be obtained by the use of air compressors &c. |
