Method of and apparatus for filtering

DETAILED DESCRIPTION The present invention relates to an improved filtration method and apparatus, and more particularly to a series of communicating filtration vessels and filtration media layers.
It is an object of the present invention to provide a series of deep bed filters which will give improved filtration of liquids.
It is a further object of the invention to provide a liquid filter apparatus and method to handle varying loads of suspended contaminants flowing into the filter.
It is yet a further object of the invention to adequately filter liquids in waste treatment facilities during upset conditions.
Very simply defined the present invention consists of four or more distinct layers of granular filter media situated in two or more separate filter beds.
The first bed is comprised of one or more layers of filter media, and the following filter beds are each comprised of two or more layers of granular filter media.
The filter beds are in series but not in direct contact with each other.
Contaminated liquid flows successively downwardly through the first bed, through an appropriate conduit means to the second bed, downwardly through that bed and then to and through any further filter beds.
The filter media is successive layers in the direction of filter flow begins with the coarsest material and becomes successively finer from layer to layer.
The average size of the filter media decreases from layer to layer in the direction of filter flow.
The filtration flow rate per square foot of filter bed inlet area also successively decreases in the filter beds in the direction of filtration flow due, for example, to an increase in width of successive filter beds.
The filter is designed to handle the changes in flow rate and dirt load that often exist in the treatment of municipal and industrial wastes.
Ideally, filter media should begin with very coarse granules and gradually reduce in size to finer and finer granules.
Such an arrangement entraps the largest contaminants first and successively entraps smaller particles as contaminated liquid passes through the finer granular layers