Water filter

Claim 1

A fluid filter comprising: a. a housing containing a plurality of beds of filter media connected in series, each of said beds being confined in a substantially horizontal direction by at least two substantially vertical means pervious to the flow of fluid, means to admit in-flow fluid to a first bed of said series, said beds being constructed and arranged such that the in-flow flows through said beds in sequence and in a substantially horizontal direction, means to withdraw fluid from a last bed of said series, b. each of said beds including an expansion chamber located above said beds, said chamber being enclosed in the horizontal direction by impervious walls substantially coextensive with said pervious means whereby the bed is unconfined in the vertical direction, said filter media filling said beds to a level substantially below the top of said chambers, c. individual means in each bed for selectively backwashing and fluidizing by expanding the filter media into said expansion chamber in each of said beds simultaneously or individually, said individual backwashing and fluidizing means being located at the bottom of each of said beds, d. individual means for exhausting backwash fluid from the top of each of said beds whereby flow of backwash fluid through said beds is upward substantially normal to the direction of flow of the in-flow. e. whereby said exhausting means and said selective backwashing means control the flow of backwash fluid through each of said beds and fluidizes essentially only such bed being backwashed.

Claim 11

A method of filtering a liquid and backwashing a series of filters comprising: a. providing an inlet and an outlet for liquid being filtered, b. providing a plurality of filter beds substantially transverse to the liquid flow, said beds being formed by: 1. positioning substantially vertical pervious material across the liquid flow; 2. providing an expansion chamber above each of said beds, said chamber having impervious walls substantially coextensive with said pervious material whereby the bed is unconfined in the vertical direction; 3. placing different sized filter media in each of said beds to a level substantially below the top of said chambers; 4. filtering the liquid successively through each of said beds; c. selectively backwashing said beds individually or simultaneously in an upward direction at a sufficient pressure for fluidizing the beds by expanding the filter media into said chamber only in such bed or beds being backwashed by forcing backwash fluid up from the bottom of the bed and out the top thereof through an independent backwash outlet.

Claim 12

A method of filtering a liquid and backwashing a series of filters comprising: a. providing an inlet and an outlet for liquid being filtered, b. providing a plurality of filter beds substantially transverse to the liquid flow, said beds being formed by: 1. positioning substantially vertical pervious material across the liquid flow; 2. providing an expansion chamber above each of said beds, said chamber having impervious walls substantially coextensive with said pervious material whereby the bed is unconfined in the vertical direction; 3. placing different sized filter media in each of said beds to a level substantially below the top of said chambers; 4. filtering the liquid successively through each of said beds; c. selectively backwashing said beds individually or simultaneously in an upward direction at a sufficient pressure for fluidizing the beds by expanding the filter media into said chamber only in such bed or beds being backwashed by forcing backwash fluid up from the bottom of the bed and out the top thereof through an independent backwash outlet.