Rotary drum filter

Claim 2

A drum structure for a rotary drum filter, comprising a generally annular rotatable drum, a plurality of rib elements extending generally longitudinally along the circumference of said drum and circumferentially spaced around said drum to define a plurality of filtrate compartments extending generally longitudinally along the drum circumference, a plurality of cover elements mounted generally longitudinally and circumferentially around said drum radially spaced from the drum circumference by said filtrate compartments, a foraminous filter medium overlying said cover elements and spaced from therefrom to provide filtrate passages intermediate said cover elements and said filter medium, said cover elements being provided with filtrate drainage openings connecting said filtrate passages with said filtrate compartments for draining filtrate from said filtrate passages to said filtrate compartments, and louver means adjacent said drainage openings for causing filtrate draining through said drainage oPenings to be discharged to said filtrate compartments in a direction at least generally longitudinally of said filtrate compartments.

Claim 3

A drum structure according to claim 1, wherein said louver means are unitary with said cover elements and slope inwardly from said cover elements into said filtrate compartments.

Claim 4

A drum structure according to claim 2, wherein said drainage openings are of generally slot-like configuration.

Claim 5

A drum structure according to claim 2, wherein the drainage openings of each cover element are at least generally aligned in the longitudinal direction of said drum.

Claim 6

A drum structure for a rotary drum filter, comprising a generally annular rotatable drum, a plurality of generally upstanding rib elements extending generally longitudinally along the outer circumference of said drum and circumferentially spaced around said drum one from another to define a plurality of filtrate compartments extending generally longitudinally along the outer circumference of said drum, a plurality of cover elements mounted generally longitudinally and circumferentially around said drum radially spaced outwardly from the outer circumference of said drum by said filtrate compartments, a foraminous filter medium overlying said cover elements and spaced outwardly therefrom to provide filtrate passages intermediate said filter medium and the outer circumferences of said cover elements, said cover elements being provided at intervals along their lengths with drainage openings communicating said filtrate passages with said filtrate compartments for draining filtrate from said filtrate passages to said filtrate compartments and said filtrate compartments having discharge ends at which the filtrate is discharged therefrom, and louvers adjacent said drainage openings for causing filtrate draining through said drainage openings to said filtrate compartments to be discharged to said filtrate compartments in a direction at least generally towards said discharge ends of said filtrate compartments.

Claim 7

A drum structure for a rotary drum filter, comprising a generally annular rotatable drum, a plurality of generally upstanding rib elements extending generally longitudinally along the outer circumference of said drum and circumferentially spaced around said drum one from another to define a plurality of filtrate compartments extending generally longitudinally along the outer circumference of said drum, a plurality of cover elements mounted generally longitudinally and circumferentially around said drum radially spaced outwardly from the outer circumference of said drum by said filtrate compartments, a foraminous filter medium overlying said cover elements and spaced outwardly therefrom to provide filtrate passages intermediate said filter medium and the outer circumferences of said cover elements, said cover elements being provided at intervals along their lengths with drainage openings communicating said filtrate passages with said filtrate compartments for draining filtrate from said filtrate passages to said filtrate compartments and said filtrate compartments having discharge ends at which the filtrate is discharged therefrom, and louvers adjacent said drainage openings for causing filtrate draining through said drainage openings to said filtrate compartments to be discharged to said filtrate compartments in a direction at least generally towards said discharge ends of said filtrate compartments.

Claim 8

A drum structure according to claim 5, wherein said louvers are integral with said cover elements.

Claim 9

A drum structure according to claim 5, wherein said louvers comprise portions of said cover elements recessed into said filtrate compartments and said drainage openings are located adjacent the end of their respective recessed portions most adjacent to the discharge end of the communicating filtrate compartment.

Claim 10

A drum structure according to claim 5, wherein said louvers comprise portions of each cover element laterally offset from the main portion of the cover element, and said drainage openings are each located adjacent the ends of their offset portions most adjacent to the discharge end of the communicating filtrate compartment.

Claim 11

A drum structure according to claim 5, wherein the drainage openings of each cover element are generally aligned along an edge portion of the cover element.

Claim 12

A drum structure for a rotary drum filter, comprising a generally annular rotatable drum, a plurality of generally laterally upstanding rib elements extending generally longitudinally along the outer circumference of said drum and circumferentially spaced around said drum to define a plurality of filtrate compartments extending generally longitudinally along the outer circumference of said drum substantially throughout its extent, a plurality of cover elements mounted on said rib elements overlying the outer circumference of said drum and radially spaced outwardly from the drum outer circumference by said filtrate compartments, a foraminous sheet filter medium overlying said cover elements and radially outwardly spaced therefrom by drainage passages between said cover elements and said filter medium, each said cover element having an edge portion generally in the longitudinal direction of said drum which overlies a portion of a filtrate compartment, said edge portion of each said cover element at intervals along its length having transversely extending drainage openings Communicating an overlying filtrate passage with an overlaid filtrate compartment for draining filtrate from such filtrate passage to such filtrate compartments, said filtrate compartments having discharge ends at which the filtrate is discharged therefrom, and said cover elements including louvers adjacent said drainage openings for causing filtrate draining through said drainage openings to be discharged thereby in a direction towards said discharge ends of said filtrate compartments.

Claim 13

A drum structure for a rotary drum filter, comprising a generally annular rotatable drum, a plurality of generally laterally upstanding rib elements extending generally longitudinally along the outer circumference of said drum and circumferentially spaced around said drum to define a plurality of filtrate compartments extending generally longitudinally along the outer circumference of said drum substantially throughout its extent, a plurality of cover elements mounted on said rib elements overlying the outer circumference of said drum and radially spaced outwardly from the drum outer circumference by said filtrate compartments, a foraminous sheet filter medium overlying said cover elements and radially outwardly spaced therefrom by drainage passages between said cover elements and said filter medium, each said cover element having an edge portion generally in the longitudinal direction of said drum which overlies a portion of a filtrate compartment, said edge portion of each said cover element at intervals along its length having transversely extending drainage openings Communicating an overlying filtrate passage with an overlaid filtrate compartment for draining filtrate from such filtrate passage to such filtrate compartments, said filtrate compartments having discharge ends at which the filtrate is discharged therefrom, and said cover elements including louvers adjacent said drainage openings for causing filtrate draining through said drainage openings to be discharged thereby in a direction towards said discharge ends of said filtrate compartments.

Claim 14

A drum structure according to claim 10, wherein each said cover element at intervals along the length of said edge portion is laterally offset towards a filtrate compartment to provide said louvers, and said drainage openings are each located at the end of their respective offset portions most adjacent to the discharge end of the communicating filtrate compartment.

Claim 15

A drum structure according to claim 11, wherein such offset portions are adjustable to vary the flow volumes of said drainage openings.

Claim 16

A drum structure according to claim 11, wherein said cover elements cooperate to prevent substantial filtrate flow from said filtrate passages to said filtrate compartments other than through said drainage openings.

Claim 17

A drum structure according to claim 10, wherein said drainage openings are provided in the corresponding edge portion of each cover element.

Claim 18

A drum structure according to claim 11, wherein said ends of the offset portions are wider than the other ends thereof.

Claim 19

A drum structure according to claim 11, wherein said offset portions of said cover elements each gradually widen as they extend towards their said ends.