Backwash method and apparatus
First Claim
1. A method for cleaning a plurality of filter elements having inner cores vertically positioned within a filter vessel which has a tube sheet dividing the filter vessel into a lower filter compartment and an upper plenum compartment, said filter elements being positioned within said filter compartment and having upper portions that are in fluid communication with said plenum compartment through openings formed in said tube sheet, said method comprising:
- draining substantially all of the liquid from the filter compartment;
establishing a pressurized condition in said filter compartment and said filter elements that is sufficient to support a predetermined volume of backwash liquid in said plenum compartment above said tube sheet;
increasing the pressure in said plenum compartment and reducing the pressure in said filter compartment so as to cause said predetermined volume of backwash liquid to move rapidly downward through the cores of said filter elements and surge radially outward through the filter surfaces thereof.
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Accused Products
Abstract
A method and apparatus for cleaning filter elements that are vertically positioned within a filter vessel that has a tube sheet dividing the filter vessel into a lower filter compartment and an upper plenum compartment. A fixed volume of backwash liquid is rapidly directed from the plenum compartment above the tube sheet through the filter elements into the filter compartment that has been drained of liquid. The rapid movement of the backwash liquid is a result of a pressure differential between the plenum compartment and the filter compartment. The volume of backwash liquid is maintained above the tube sheet by a pressurized condition in the filter compartment, which volume may be changed by adjusting the pressure in the filter compartment.
57 Citations
9 Claims
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1. A method for cleaning a plurality of filter elements having inner cores vertically positioned within a filter vessel which has a tube sheet dividing the filter vessel into a lower filter compartment and an upper plenum compartment, said filter elements being positioned within said filter compartment and having upper portions that are in fluid communication with said plenum compartment through openings formed in said tube sheet, said method comprising:
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draining substantially all of the liquid from the filter compartment; establishing a pressurized condition in said filter compartment and said filter elements that is sufficient to support a predetermined volume of backwash liquid in said plenum compartment above said tube sheet; increasing the pressure in said plenum compartment and reducing the pressure in said filter compartment so as to cause said predetermined volume of backwash liquid to move rapidly downward through the cores of said filter elements and surge radially outward through the filter surfaces thereof. - View Dependent Claims (2, 3)
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4. Apparatus for filtering liquids, comprising:
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a filter vessel, a tube sheet dividing said vessel into a lower filter compartment and an upper plenum compartment, a plurality of filter elements vertically mounted in said filter compartment, said filter elements having upper portions that communicate with said plenum compartment through openings formed in said tue sheet, said upper portions of said filter elements extend a short distance into said plenum compartment and a cap member is supported in covering relationship and spaced from said upper portions of said filter elements, said cap members having lower end portions spaced from said tube sheet; means for draining at least a portion of the liquid from the filter compartment; means for establishing a pressurized condition in said filter compartment and said filter elements that is sufficient to support a predetermined volume o backwash liquid in said plenum compartment above said tube sheet; means for directing said predetermined volume of backwash liquid into said plenum compartment; means for increasing the pressure in said id plenum compartment and means for reducing the pressure in said filter compartment so as to cause said fixed volume of backwash liquid to move rapidly downward through the cores of said filer elements and surge radially outward through the filter surfaces thereof. - View Dependent Claims (5, 6, 7, 8, 9)
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Specification