Liquid purification or separation – With repair or assembling means – Hoist or handle means
Reexamination Certificate
2000-11-09
2001-07-10
Lithgow, Thomas M. (Department: 1724)
Liquid purification or separation
With repair or assembling means
Hoist or handle means
C210S241000, C210S477000, C210S482000, C210S484000
Reexamination Certificate
active
06258268
ABSTRACT:
BACKGROUND OF THE INVENTION
Container filter boxes are commonly used to separate solid particles from a mixture of solids and liquid (usually water) for disposal. Examples of applications for such filter boxes include filtering wet contaminated soil from a construction site where the liquid is drained from the sludge prior to disposal and filtering sediment taken from the bottoms of refinery storage tanks which is generally a heavily liquid-laden material. Typically, container filter boxes comprise an outer liquid-impermeable rectangular shell having an open upper end and an inner filtering shell having an open upper end and perforated bottom, side and end walls. The inner shell is supported within and spaced from the outer shell by a support frame so as to define a material collection area between the inner and outer shells. The inner shell is lined with a disposable filter cloth of a desired mesh size. These filter boxes are loaded with sludge or other liquid-laden material through their open upper end, whereupon liquid and smaller solid particles pass through the filter cloth liner and the perforated inner shell into the spacing between the inner and outer shells where they are removed through drains provided on the bottom of the outer shell. The inner and outer shells also define a large hinged door at one end of the box to provide access to the interior of the filter box for removal of the larger solid material retained on the inner shell. However, some of the finer solids which pass through the perforated inner shell of the filter box do not pass through the drains and become trapped between the inner and outer shells. Solid material also falls into the area between the walls of the two shells during the loading of the filter box which can both contaminate the liquid collected between the bottom walls of the shell and add to the volume of trapped solid material. Removal of the trapped material is attempted by directing water under pressure through the perforations in the inner shell with the hinged end door in the open position in an effort to flush the trapped solid particles out from between the shells through the open ends of the two shells. Users of these container boxes, however, have experienced substantial difficulty in obtaining a thorough cleaning of these boxes following use. The filter box of the present invention both obviates the cleaning problem and prevents solids from passing between the walls of the box during loading.
SUMMARY OF THE INVENTION
Briefly, the present invention relates to container filter boxes having an outer shell with an open upper end and constructed of a liquid-impermeable material and an inner shell having perforated sides and flooring and an open upper end. The inner shell is optionally provided with a disposable filter cloth liner and disposed within the outer shell and spaced therefrom so as to define a material collection area between the two shells. Upon loading liquid-laden material into the filter box through the open upper end thereof, the liquid and smaller solids pass through the filter liner and perforated sides and flooring of the inner shell into the collection area leaving the larger solids within the inner shell for removal. One end of the filter box defines a hinge-mounted door for providing access to the interior of the box for removal of the larger solids as well as access to one end of the material collection area. In the present invention, one or more pivotally mounted perforated hatch plates are provided in the flooring of the inner shell adjacent the opposite end of the filter box from the hinged access door, and optionally in the side walls of the inner shell, to provide additional access to the material collection area. By positioning the hatch plates at the opposite ends of the filter box from the hinged end door, the user, upon completion of the filtering operation, can open the hatch plates and the hinged end door and direct a flow of pressurized water from a location proximate the hatch plates through the entire length of the filter box between the inner and outer shells and thereby effectively wash out any material trapped therein. To prevent solids from falling down between the inner and outer shells of the filter box during loading, the inner shell defines an outwardly projecting lip which extends over and about the opening between the inner and outer shells at the upper ends thereof thereby preventing possible contamination, reducing the volume of solids in the collection area and generally increasing the efficiency of the filtering process.
It is therefore the principal object of the present invention to provide a container filter box for de-watering which facilitates thorough cleaning of the filter box following the filtration process and improves separation of solids and liquids.
It is another object of the present invention to provide a container filter box for de-watering which reduces contamination in the bottom of the container by preventing the passage of unfiltered solids between the upper ends of the inner and outer shells and into the bottom of the container.
These and other objects and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 4871454 (1989-10-01), Lott
patent: 4929353 (1990-05-01), Harris
patent: 5589081 (1996-12-01), Harris
patent: 5595654 (1997-01-01), Caughman, Jr.
patent: 5681460 (1997-10-01), Caughman, Jr.
patent: 5707535 (1998-01-01), Harris
patent: 6004461 (1999-12-01), Harris
patent: 6146528 (2000-11-01), Caughman, Jr.
patent: 3801817 (1989-08-01), None
Lithgow Thomas M.
Lyon & Lyon LLP
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