WO1997044111B1

WO1997044111B1 - Radial-flow fluidizable filter

Info

Publication number: WO1997044111B1
Application number: PCT/US1997/008942
Authority: WO
Filing date: 1997-05-23
Publication date: 1998-01-29
Anticipated expiration: 1998-11-23

Abstract

A radial-flow filter (120) employing nonbonded granular particles (56) for filtering impurities from an influent, and that can be backwashed by fluidizing the granular particles (56) to free the impurities therefrom. During a backwashing operation, a backwash liquid applies an upwardly-directed drag force on an upper portion of the granular particles (56) to lift the same into a backwash chamber (62) for fluidization. Once the top portion of the granular particles (56) of the filtration bed is fluidized, the backwash liquid applies an upward force on a subsequent portion of the granular bed, thereby fluidizing the granular particles (56) in the backwash chamber (62). Subsequent sections of the granular bed are fluidized in a similar manner to thereby completely clean the granular particles (56). After the backwash operation, the granular particles (56) fall back to the filtration chamber (156) and form a filter bed for carrying out a filtration operation.

Claims

AMENDED CLAIMS[received by the International Bureau on 12 December 1997 (12.12.97); original claims 1, 3, 5, 8, 13, 15, 17 and 18 amended; new claim 23 added; remaining claims unchanged (3 pages)]

1. A device for fluidizing a media, comprising: a media for coacting with an influent; a support structure defining a first chamber for containing said media so that said influent passes radially through said media and coacts therewith; an inlet structure for directing the influent to said media so as to flow radially through said media; and a fluidizing chamber different from said first chamber to which substantially all said media is carried during fluidizing thereof, said fluidizing chamber being of a sufficient volume for allowing said media to separate into particles when carried from said first chamber to said fluidizing chamber.

2. The device of Claim 1, wherein said fluidizing chamber is located above said media during a media coaction operation.

3. The device of Claim 1, wherein said fluidizing chamber is of a volume of about the same as a volume of said first chamber containing said media during the coaction with the influent.

4. The device of Claim 1, wherein said device is structured so that said media is carried axially to said fluidizing chamber during a fluidizing operation.

5. The device of Claim 1, wherein said support structure comprises a pair of concentric support structures, and further including one or more orifice structures fixed within an inner support structure of said pair to restrict a flow of the influent within said inner support structure.

6. The device of Claim 5, wherein said orifice structure comprises a plate with an orifice therein.

7. The device of Claim 5, wherein said orifice structure comprises a check valve.

8. The device of Claim 5, wherein a first orifice structure has an effective open area different from other said orifice structures.

9. The device of Claim 8, wherein an effective open area of each said orifice structure decreases in area for orifice structures located from a fluid inlet of said device to said fluidizing chamber.

10. The device of Claim 5, further including an obstruction plate fixed within said inner support structure to prevent a flow of fluidizing fluid axially therethrough, thus directing the flow from said inner support structure through said media.

11. The device of Claim 1 , wherein said support structure comprises a pair of concentric structures, and wherein said device is structured so that influent passes axially inwardly through an outer support structure of said pair of concentric support structures during a coacting operation, and the fluidizing fluid does not continuously pass through said outer support structure during a fluidizing operation.

12. The device of Claim 3, wherein said media is contained in an annular volume between concentric portions of said support structure, said annular volume having a first radial dimension, and said fluidizing chamber is characterized by an annular volume having a larger radial dimension.

13. The device of Claim 1, wherein said device comprises a filter, and said media comprises granular particles.

14. The device of Claim 13, wherein said fluidizing chamber comprises a backwash chamber.

15. A method for coacting a media with an influent, and for fluidizing the media, comprising the steps of: supporting said media in a first volume; passing the influent radially through the media; coacting the media with the influent; and fluidizing the media by transporting the media to a second volume, thereby separating the media into particles.

16. The method of Claim 15, further including moving the media axially during a fluidizing operation.

17. The method of Claim 16, further including moving the media to a fluidizing chamber that is distinct from the first volume.

18. The method of Claim 15, further including fluidizing said media into particles by movement thereof to said second volume.

19. The method of Claim 18, further including sequentially fluidizing distinct portions of the media during different periods of time.

20. The method of Claim 19, further including applying about the same drag force to each said portion of particles during said sequential fluidizing.

21. The method of Claim 18, further including decreasing a flow rate of the fluidizing fluid as a result of complete fluidizing of said media.

22. The method of Claim 21, further including decreasing the flow rate by causing an accumulation of the fluidized media over an exit area of the fluidizing fluid.

23. The method of Claim 19, further including containing the media in a first volume defined by concentric inner and outer perforated cylinders, and further including enclosing said outer perforated cylinder with a cylindrical case and isolating sections of an annulus defined by a space between said outer perforated cylinder and said cylindrical case by using one or more o- rings.

STATEMENT UNDER ARTICLE 19

The claims have been amended to clarify the meaning thereof and to further distinguish the invention from the prior art identified in the search report, and particularly the Schmid patent reference. Claim 1 now specifies that substantially all of the media is carried to the fluidizing chamber, which chamber is different from the support structure first chamber where the media radially coacts with an influent. As noted in the Schmid reference, the air injected into the filter by way of the five upright tubes 62 and the five conduit means 66 causes the media to turn into a "violently boiling media" so that a recirculation of the media in the filter chamber is accomplished.

Claim 15 specifies that the media is in a first volume so that the influent passes radially therethrough for coacting therewith, but during fluidizing, the media is transported to a second volume where the particles are separated. This distinguishes from the Schmid patent where both the filtering operation and the fluidizing operation are carried out in the same chamber, namely the filtering chamber. If the filter particles of the Schmid filter were to be carried upwardly for fluidizing, they would flow out of the open top of the casing and out of the overflow (Col. 5, lines 55, 57).