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 an upper filter compartment and a lower plenum compartment, said filter elements being positioned within said filter compartment and having fittings which extend through said tube sheet downwardly into said plenum compartment, said method comprising:
- draining at least a portion of the liquid from the filter vessel, establishing a low flow rate of backwash liquid through a backwash inlet line into the plenum compartment continuing through the filter elements; and
intermittently directing gas under pressure through a gas supply line in communication with an external vessel containing a volume of cleaning liquid for forcing a predetermined volume of the cleaning liquid from the external vessel under gas pressure at a high flow rate into the plenum compartment and through the filter elements such that the total volume of cleaning liquid directed through the filter elements during each cycle is in the range of 1.0 to 3.0 times the total filter element core void volume.
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Accused Products
Abstract
The method and apparatus for filtering a liquid including a filter vessel divided into an upper filter compartment and a lower plenum compartment. An external vessel is positioned at or below the elevation of the tops of the filter element fittings in the plenum compartment. A pressurized gas is supplied to the upper portion of the external vessel forcing backwash liquid from the external vessel into the lower portion of the plenum compartment backwashing filter elements within the filter compartment.
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Citations
11 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 an upper filter compartment and a lower plenum compartment, said filter elements being positioned within said filter compartment and having fittings which extend through said tube sheet downwardly into said plenum compartment, said method comprising:
- draining at least a portion of the liquid from the filter vessel, establishing a low flow rate of backwash liquid through a backwash inlet line into the plenum compartment continuing through the filter elements; and
intermittently directing gas under pressure through a gas supply line in communication with an external vessel containing a volume of cleaning liquid for forcing a predetermined volume of the cleaning liquid from the external vessel under gas pressure at a high flow rate into the plenum compartment and through the filter elements such that the total volume of cleaning liquid directed through the filter elements during each cycle is in the range of 1.0 to 3.0 times the total filter element core void volume. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- draining at least a portion of the liquid from the filter vessel, establishing a low flow rate of backwash liquid through a backwash inlet line into the plenum compartment continuing through the filter elements; and
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8. Apparatus for filtering liquids comprising:
- a filter vessel;
a tube sheet dividing said vessel into an upper filter compartment and a lower plenum compartment;
a plurality of filter element fittings extending through said tube sheet and downwardly into said plenum compartment;
a plurality of filter elements vertically mounted on said fittings in said filter compartment;
an external vessel positioned outside of said filter vessel at an elevation at or below the elevation of the tops of said fittings;
a gas supply line in communication with an upper portion of said external vessel;
a backwash liquid inlet line in communication with a lower portion of said plenum compartment and a lower portion of said external vessel; and
a gas surge line in communication with a lower portion of said external vessel and an upper portion of said plenum compartment. - View Dependent Claims (9, 10, 11)
- a filter vessel;
Specification