| 摘要 |
990,807. Large-scale filters for liquids. FULLER CO. Aug. 13, 1963 [Feb. 18, 1963], No. 31988/63. Heading B1D. The Figure illustrates, diagrammatically only, apparatus including six filter beds (of which only two are shown) whose underdrain spaces communicate by means not shown. They are radially arranged around a cylindrical doublewalled core 10. Liquid to be filtered introduced at 13 passes into an annular trough 14 whence it is withdrawn, as shown on the left of the Figure, by an inlet siphon 16 communicating with a weir box 62. From the weir box the liquid flows over a weir into a duct formed by radial partitions in the double wall and flows out at 56 into the forebay 26 of the appropriate filter bed. Filtrate is received in a retention tank 36 provided with a weir. For backwashing any bed, a valve 68 is operated to connect siphon 16 to atmosphere instead of to vacuum tank 66, and thereby stop inflow. Next, a valve 72 is operated to connect a backwash siphon system (see below) to another vacuum tank 70. The backwash siphon system consists of two further ducts (52 being one of them) within the double wall, which are connected only at the top by a weir 55 (on the right of the Figure) and are closed by a cover 54. Filtrate from tank 36 (maintained at the height shown by continued operation of the remaining filter beds) passes along the underdrain spaces, upwards through the bed on the right, into horizontal backwash channels (not shown), into the forebay 26, through a port 56 into one of the backwash conduits, up the conduit and over weir 55 into the other conduit, and out of the latter by a port 58 laterally spaced (not as shown) from port 56. The liquid thus reaches an inner chamber 50 where a certain level is maintained by a weir box (on the extreme right of the apparatus) to which leads a discharge pipe 76. Vacuum for the backwash siphon systems is provided by a vacuum pump connected at 73, while that for the inlet siphons is provided by a tube 79 depending from tank 66 and opening within liquid in a tube 77 at a height H above the liquid level in chamber 50. (Tube 77 depends from tank 70 and opens within the liquid in chamber 50). |
