Downflow filter with high velocity backflush

摘要: A method and apparatus for backflushing downflow filters is disclosed which comprises providing a closed container having contiguous, vertically adjacent filter layers. layer of gravel provided below the layers separated from bottom by foraminous retention member. Fluid under pressure introduced through plurality fluid nozzles into to backflush Backflush in at sufficient flow rate fluidize all segregate them accordance with their specific densities particle size. Introducing helps prevent development localized areas high velocity that can cause intermingling during backflush.