Abstract: A drinking water filter inhibits retrograde bacteria growth at the user outlet with the combination of a non-carbonaceous submicron filter element immediately upstream of the system outlet and a copper orifice element in the outlet downstream of the filter element. The copper orifice element preferably comprises a thin copper disc having a single orifice. The submicron filter element preferably comprises a hollow fiber bundle filter element.

Abstract: A method and apparatus is provided for the continuous extrusion of porous activated carbon block filter elements. The invention includes feeding material into the barrel of a screw extruder and heating the material therein such that the material becomes an agglomerated mass. The agglomerated mass is agitated and compacted into a die where it is cooled to a semi-solidified state. In the semi-solidified state, the material is passed through a cooling tunnel where the material solidifies and the carbon block filter element is formed. A back pressure control device is also included to control pressure in the die.

Abstract: An extruder for plasticating and extruding an extrudate, and an extrusion screw used with the extruder form the subject of this invention. The extruder screw includes an elongated root body and a thread portion helically wound about the root body and extending along the length. The screw having a low compression ratio, flight with a reduced helical angle, and a conical, tapered front end section where at least one-half flight of the thread has a pitch associated therewith which is different from the pitch of the remainder of the thread and where the diameter is less than the diameter of the remainder of the root body.

Abstract: An extruder for plasticating and extruding an extrudate, and an extrusion screw used with the extruder form the subject of this invention. The extruder screw includes an elongated root body and a thread portion helically wound about the root body and extending along the length. The screw having a low compression ratio, flight with a reduced helical angle, and a conical, tapered front end section where at least one-half flight of the thread has a pitch associated therewith which is different from the pitch of the remainder of the thread and where the diameter is less than the diameter of the remainder of the root body.

Abstract: A pour-through pitcher filter assembly includes a compact filter element including a thin annular disk of molded activated carbon and a peripheral annular seal element. The seal element allows the filter to be replaceably mounted in the lower end of a plastic reservoir, which reservoir is adapted to be supported in the top of a pitcher for receiving filtered water. The reservoir may be made by a blow molding process and includes an integral bellows member which is manually collapsible to pressurize the interior of the reservoir to initiate gravity flow through an initially dry filter element. The seal element utilizes a synthetic rubber material and is preferably insert molded around the carbon filter disk.

Abstract: A composite cartridge type filter of the kind utilizing a hollow cylindrical body of bonded activated carbon and an interior filled with a particulate filter media bed is disposed within a housing such that raw unfiltered water passes radially inwardly through the carbon body, into the interior media bed and then axially through the media bed to an outlet in one end. To balance the radial flow of water through the carbon body and maximize contact with the particulate media bed, a flow distribution device is disposed in the interface between the carbon body and the particulate filter media bed to distribute a portion of the flow toward the end of the media bed which is remote from the cartridge outlet. In this manner, short circuiting of the water through the filter is eliminated, radial flow through the carbon body is balanced, and a substantial portion of the flow is forced to follow a path which carries it through substantially the full length of the particulate media bed.