| 摘要 |
<p>A method and apparatus are presented for rejuvenating a bed of granular filter medium that has accumulated contaminants during filtration of a liquid stream. The method first includes the step of establishing a small volumetric flow of clean filtrate in reverse flow. Then the filter medium is agitated to break-up contaminants that have become agglomerated on the surface of or within the interstitial spaces of the filter medium. The agitating step is accomplished by exposing the liquid-full filter medium to a jetting stream comprised mostly of a gas mixed with a clean liquid. The jetting stream is dispersed throughout the filter medium through a plurality of radial nozzles located within the filter bed.; The radial nozzles disperse the gas within the liquid and filter medium causing sufficient turbulence and agitation of the filter medium granules to liberate the trapped contaminants without the need for high liquid flow rates. The number of nozzles and their placement within the filter bed are varied depending on factors such as size and shape of the filter vessel and the type of filter media being cleaned. The amount of water and gas flowing through the nozzles is also adjusted to provide substantially uniform cleaning of the entire bed. This method results in lower volumes of clean filtrate being consumed in the backwash cycle and the associated storage and recycle of that liquid back into the process.; The radial nozzles are each comprised of two horizontal and parallel circular disks spaced apart to create a cylindrical void through which the pressurized gas and liquid jetting stream flows. The apparatus presented comprises a singular filter vessel and a plurality of filter chambers within a common filter vessel each containing granular filter medium and a plurality of radial nozzles disposed with the medium for dispersing the jetting stream throughout during the cleaning and rejuvenation steps of a filtering process.</p> |
