Patent ID: 9174149
Filing Date: 2015-11-03
Classification: B01D

Abstract:
1. A deep bed filter for filtering contaminants from a contaminated liquid stream, comprising: a vessel defining an internal space for containing a liquid to be filtered; a bed of granular filter medium disposed inside the vessel in at least a lower region thereof; inlet connection and distribution means situated in an upper region of the vessel, for receiving a contaminated liquid and distributing that liquid downwardly and substantially uniformly across the vessel cross section during a filtering cycle; outlet filter means, situated in said lower region of said vessel and low in said filter medium, coupled to and circumferentially surrounding an outlet conduit, for withdrawing filtered liquid from the vessel while retaining the granular filter medium within the vessel during said filtering cycle; at least one radial nozzle or a plurality of evenly spaced radial nozzles situated low in the vessel and within said medium and located in close proximity to the outlet filter means, for dispensing radially outwardly therefrom during a rejuvenation cycle a controlled mixture of gas and liquid comprising a gas-liquid dispersion wherein gas bubbles are substantially uniformly entrained and dispersed in said liquid in a controlled ratio to said liquid and to agitate and fluidize during said rejuvenation cycle the granular filter medium low in said vessel in at least a region of said medium at which said outlet filter means is situated; at least one conduit disposed within the vessel for transporting the controlled mixture of gas and liquid to said at least one radial nozzle; and backwash removal means, situated in said upper region of said vessel and separate from said inlet connection and distribution means and said outlet filter means, for withdrawing the controlled mixture of gas and liquid from the vessel during the rejuvenation cycle while retaining the granular filter medium within the vessel during said rejuvenation cycle.