Patent ID: 6416661
Filing Date: 2002-07-09
Classification: B01D,E21B

Abstract:
A screen filter assembly for installation in a hole formed in fluid bearing formations to filter fluid passing therethrough, the filter assembly comprising:a double walled tubular screen filter including: an outer cylindrical perforated screen member; an inner cylindrical perforated screen member aligned concentrically with the outer screen member, said inner screen member having a smaller diameter than said outer screen member and positioned to define an annular filter space therebetween; a filter medium substantially filling the annular filter space between the screen members for filtering particulate materials from fluid passing through the medium and wherein the filter medium comprises granules of material having a predetermined size; an upper end cap secured to an upper end of each of the spaced apart screen members to seal the annular space therebetween; a lower end cap secured to a lower end of each of the spaced apart screen members to seal the annular space therebetween; a tubular member aligned concentrically and extending through the screen filter, the tubular member adapted for passage of fluid and having a perforation to allow fluid to pass through the screen filter and into the tubular member; and wherein the screen filter is adapted for slidable removal and replacement along the axial length of the tubular member.