US 4,358,370 A · Backwashable filter

Abstract

A backwashable filter comprises a generally cylindrical housing with an inlet and an outlet, a cylindrical filter basket located within the housing between the inlet and the outlet, and a backwashing arm bearing against the inside face of the filter basket and arranged to rotate about the axis of the filter basket. The filter basket is formed by an inner and outer perforated cage with a filter medium interposed between them. The outer surface of the inner cage is configured to provide channelling between the inner cage and the filter medium to allow liquid to be filtered to contact substantially all of the inner surface of the filter medium. Direct flow of liquid to be filtered from the inside of the inner cage into the backwashing arm along the channelling is prevented by arranging the channelling axially or by arranging the channelling in the circumferential direction and then providing a wide shoe on the backwashing arm.

Claims15

Dependent claims

In a backwashable filter comprising a generally cylindrical housing with an inlet opening into said housing and an outlet opening from said housing, a cylindrical filter basket within said housing and interposed between said inlet and said outlet, a backwashing arm bearing against the inside of said filter basket and being rotatable about an axis of said filter basket, the improvement wherein said filter basket comprises:

an inner and an outer perforated cage;
a filter medium interposed between said inner and outer cage;
an outer surface of said inner cage having channels to allow liquid to be filtered to contact substantially all of an inner surface of said filter medium;
and
means to prevent direct flow of said liquid to be filtered from inside of said inner cage into said backwashing arm.

2 more elements

Dependencies are inferred from the claim text.

Backwashable filter

Life of this patent

Backwashable filter

Life of this patent

Abstract

Claims15