Liquid purification or separation – Recirculation – Serially connected distinct treating or storage units
Reexamination Certificate
1998-03-30
2001-01-23
Simmons, David A. (Department: 1724)
Liquid purification or separation
Recirculation
Serially connected distinct treating or storage units
C210S258000, C210S330000, C210S385000, C210S388000, C210S391000, C210S408000
Reexamination Certificate
active
06177006
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a filtering device and, more particularly, to a filtering device suitable for precision filtering in a state submerged in liquid to be treated. Liquid to be treated includes water for general uses, drinking water, river water, pool water and various other liquids.
Known in the art of filtering devices is one which employs a plurality of filter tubes. In this filtering device, a plurality of fiter tubes are provided in parallel in a container. Liquid to be treated is introduced from an inlet provided in one end portion of the container via a pump and filtered through these filter tubes and treated liquid is delivered out of a treated liquid outlet provided in the other end of the container.
For the filter tubes used in the prior art filtering device, filter elements for precision filtering which consist of a porous material or a filtering cloth having densely formed pores are used. In these filter elements, however, pores of these filter elements are blocked by fine powdery materials suspending in the liquid to be treated in a relatively short period of time after starting of operation of the filtering device with the result that filtering efficiency is rapidly dropped. For this reason, the filtering operation of the filtering device has to be stopped for performing reverse washing of the surface of the filter elements and resumed after removing the materials which have blocked the pores of the filter elements. Such stopping of the filtering operation and performing of reverse washing need to be repeated frequently during the filtering operation with resulting decrease in the working efficiency. Besides, the blocking of the inside of pores of the filter elements advances notwithstanding the repetition of reverse washing until at last it becomes necessary to take out all of the filter elements from the filter tubes and replace them by new filter elements.
It is, therefore, an object of the present invention to provide a novel high precision filtering device having a high filtering efficiency which is capable of preventing blocking of filter elements while continuing the filtering operation without stopping the filtering operation for performing reverse washing.
SUMMARY OF THE INVENTION
For achieving the above described object of the invention, there is provided a filtering device comprising a container having an inlet for introducing liquid to be treated, a screen provided in the container having an outlet for delivering out treated liquid, and flow creating means for creating, in said container, a flow of the liquid to be treated having a direction which is different from direction of a flow of the liquid to be treated into the screen.
According to the invention, a flow of the liquid to be treated having a direction which is different from direction of a flow of the liquid to be treated into the screen is created and powdery suspending solid particles in liquid to be treated which tend to be deposited on the surface of the screen as the liquid enters the screen are washed away from the surface of the screen by this flow having the different direction from the flow into the screen, so that these suspending solids are kept away from the surface of the screen whereby blocking of the screen can be prevented. The filtering device according to the invention therefore can prevent blocking of filter elements while continuing the filtering operation without stopping the filtering operation.
Since this filtering device does not require a bulky device for reverse washing or scraper as in the prior art filtering device, the filtering device can be constructed in a relatively compact design and at a reduced cost.
In one aspect of the invention, said flow creating means is means for reciprocating the screen vertically in the liquid to be treated.
In another aspect of the invention, said flow creating means is means for rotating the screen horizontally in the liquid to be treated.
In another aspect of the invention, said flow creating means is means for reciprocating the screen horizontally.
In another aspect of the invention, said flow creating means is a combination of at least two of means for reciprocating the screen vertically, means for rotating the screen horizontally and means for reciprocating the screen horizontally.
In another aspect of the invention, said flow creating means is means for creating a vortex in the liquid to be treated.
For creating a vortex, the flow creating means may be the inlet of the container which is arranged horizontally obliquely with respect to a line normal to the circumference of the container.
For creating a vortex, said flow creating means may be a stirrer provided in the container.
In another aspect of the invention, the filtering device comprises at least two of said containers and connecting pipes connecting said two containers together in communication to each other and wherein said flow creating means is a turbine or a pump provided in one of said connecting pipes.
These and other features and advantages of the invention will become apparent from the description made below in conjunction with the accompanying drawings.
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patent: 0719890 (1996-07-01), None
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European Search Report, The Hague, Jul. 8, 1999, Examiner Plaka, T.
Hedman, Gibson & Costigan, P.C.
Prince Fred
Simmons David A.
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