Liquid purification or separation – Structural installation – Closed circulating system
Reexamination Certificate
1999-10-01
2001-05-29
Lithgow, Thomas M. (Department: 1724)
Liquid purification or separation
Structural installation
Closed circulating system
C210S275000, C210S277000, C210S266000, C210S202000, C210S278000, C210S284000, C210S287000, C210S290000, C210S416200
Reexamination Certificate
active
06238556
ABSTRACT:
BACKGROUND OF THE INVENTION
Many types of fluidized beds are known in the art. For example, U.S. Pat. No. 4,322,296 discloses a method for waste water treatment in a vessel having a fixed perforated plate and a movable perforated plate. A particulate carrier having a specific gravity greater than water is employed as the filtering medium within the vessel.
As a further example, U.S. Pat. No. 5,453,183 discloses a fluidized bed biological filter system for fish tanks. This system utilizes glass beads having a specific gravity greater than 1.5 times that of water as particulate media.
In these filtration systems, contaminated water is passed through a negatively buoyant particulate medium. Thus, these systems only accomplish one type of filtration, i.e., filtration through a particulate carrier having a specific gravity greater than water.
SUMMARY OF THE INVENTION
The present invention is a filtration system for filtering particulate matter from a liquid. The filtration system comprises a pre-filtration apparatus and a main filtration apparatus. The pre-filtration apparatus comprises a vessel having a fluid inlet, a fluid outlet, and a back-washing outlet, and a filtering medium disposed in the vessel and capable of filtering large particulate matter from the liquid and passing fine particulate matter.
The fluid inlet and the fluid outlet are positioned such that liquid flowing therebetween is passed through the filtering medium. The fluid outlet and back-washing outlet are positioned such that liquid flowing therebetween is passed through the filtering medium.
The main filtration apparatus comprises a vessel having a fluid inlet, a fluid outlet, and a filtering medium disposed in the vessel and capable of filtering fine particulate matter from the liquid. The fluid inlet and the fluid outlet are positioned such that liquid flowing therebetween is passed through the filtering medium.
A pump is fluidly connected between the pre-filtration apparatus and the main filtration apparatus. The pump has a suction side and a discharge side.
A pre-filter control assembly is fluidly connected between the pre-filtration apparatus and the pump. The pre-filter control assembly has a normal operation setting wherein the fluid outlet of the pre-filtration apparatus is fluidly connected to the suction side of the pump to draw liquid sequentially through the fluid inlet of the pre-filtration apparatus, and the filtering medium of the pre-filtration apparatus. The pre-filter control assembly is also provided with a back wash operation setting wherein the fluid outlet of the pre-filtration apparatus is fluidly connected to the discharge side of the pump to force liquid sequentially through the fluid outlet of the pre-filtration apparatus, the filtering medium of the pre-filtration apparatus, and the fluid outlet of the pre-filtration apparatus. Thus, the pre-filtration apparatus functions as a vacuum container during normal operation and as a pressurized container during back wash.
In one aspect of the present invention, the fluid outlet of the pre-filtration apparatus is offset laterally from a centrally disposed elongated axis of the vessel of the pre-filtration apparatus. The lateral offset of the fluid outlet causes a turbulent vortex to form in the pre-filtration apparatus during back washing to more effectively scour and remove the accumulated particulate matter from the filtering medium.
Other advantages and features of the present invention will become apparent to those of ordinary skill in the art when the following detailed description is read in conjunction with the appended claims and the attached drawings.
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purex triton Swimming Pool Systems; “DE Filters”; pp. 9 and 84.
purex triton Swimming Pool Systems; “Sand Filters”; p. 4 and p. 6.
purex triton Swimming Pool Systems; “Sand Filters”; Valves, Kits and Accessories for Side Mounted Sand Filters.
Cryer Gary D.
Hawk William D.
Dunlap Codding & Rogers P.C.
Fluid Art Technologies, LLC
Lithgow Thomas M.
LandOfFree
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