Liquid purification or separation – Processes – Separating
Reexamination Certificate
2000-02-09
2001-08-07
Popovics, Robert (Department: 1723)
Liquid purification or separation
Processes
Separating
C210S791000, C210S391000, C210S396000, C210S402000, C210S408000, C210S157000, C210S158000
Reexamination Certificate
active
06270684
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of screening equipment such as equipment used in water or waste water treatment plants.
BACKGROUND
In some older sewage collection systems, for example as may found in the Eastern United States, Europe, and elsewhere, the sewage collection pipe or channel network was designed to collect sanitary sewage so that sewage transporting fecal matter and the like as well as intercept storm water is collected from streets, manholes and other sources. This storm water sometimes causes hydraulic flows to the sewage treatment plants in excess of their capacity to treat or dispose of the incoming fluid.
Some municipalities or pseudo-municipal districts have undertaken the expense of excavation and replacing these collection systems and separating the flows of sanitary sewage from storm water flows. However, this has substantial expense both in financial cost and inconvenience to the local population caused by the performance of such work. Accordingly, it is desirable to have some means to handle excess water flow systems having both sanitary waste and storm water.
There are devices now offered to intercept the larger solid material contained in such combined flows, while diverting the transporting liquid component of the flow. The liquid component will in general contain urine and finely divided solids. Still, it will be highly diluted by the storm water so that its environmental impact on a subsequent receiving body of water may be acceptable. These existing devices suffer from various problems such as vulnerability to jamming by tree branches or other large or bulky solids, blinding by solids due to relatively low cleaning water momentum, mechanical complexity and reliability issues, and operator maintenance intensity and risk exposure such as removal of net bags.
A similar and related problem exists where liquid from a body of surface water such as a river must be collected for subsequent use (i.e., a water treatment application or cooling water application as opposed to the above-described waste water application). It may be desirable to separate the trash from a quantity of the liquid without completely removing the trash from the liquid body.
Existing water intake screens used for the water treatment application suffer from difficulties similar to those for the preexisting solid intercept devices. Further, it may be difficult to meet governmental requirements regarding the subsequent disposal of the solids, i.e., trash, removed from the water.
Thus, it can be appreciated that a device solving the above-described problems would be a welcome advance in the art.
SUMMARY
The present invention relates to a method for screening solid objects from a fluid stream such as an intake stream to waste water plant or a water treatment facility. The method includes the steps of filtering a portion of the fluid stream through a screening device into a split-off stream using a screening device that is a perforated non-planar surface, and moving the screening device to assist in maintaining the screening device clear of solids. The moving may include rotation of the screening device. In a preferred embodiment, the screening device is a perforated drum, or more generally is a partial or complete surface of revolution.
The method may also include the step of cleaning the screening device, although the design of the screening device assists in maintaining the device clear of obstructions even without any additional cleaning. A number of screening devices can be used together to obtain the desired capacity.
The invention also includes structure to perform the described method.
REFERENCES:
patent: 630769 (1899-08-01), Bird
patent: 788511 (1905-05-01), Besseberg
patent: 951635 (1910-03-01), Erekson
patent: 971492 (1910-09-01), Collar
patent: 1092440 (1914-04-01), Guiu
patent: 1109385 (1914-09-01), Allison
patent: 1276374 (1918-08-01), Keller
patent: 1412230 (1922-04-01), Cuttle
patent: 2223104 (1940-11-01), Hansen
patent: 2240642 (1941-05-01), Durtschi
patent: 2328297 (1943-08-01), Roberts
patent: 5676829 (1997-10-01), Cotterill
patent: 5779887 (1998-07-01), Rector et al.
Gibson Dunn & Crutcher, LLP
Popovics Robert
Schloss Engineered Equipment, Inc.
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