Filter

Claim 2

A filter for removing liquid from a slurry, comprising: a. a first endless belt of filter fabric mounted on end rollers so as to form a horizontally-elongated loop having an upper run and a lower run, b. a second endless belt of filter fabric mounted on end rollers above the first belt so as to form a horizontally-elongated loop having an upper run and a lower run, c. means pressing the lower run of the second belt against the upper run of the first belt, d. a feed device situated at the upstream end of and above the upper run of the second belt, the material from the feed device eventually entering the nip between the lower run of the second belt and the upper run of the first belt, which runs are driven in the same direction, and e. means underlying the upper run of the second endless belt to hold it substantially flat for conveying and preliminary draining of the newly-introduced slurry.

Claim 3

A filter as recited in claim 1, wherein the feed device extends over the width of the second belt and transfers material to the second belt at a rate dependent on the speed of the belt, and wherein a pressure roller is provided having a perforated screen cylindrical surface, the roller being positioned at the downstream end of the upper run of the second belt, and pressing against that belt.

Claim 4

A filter as recited in claim 1, wherein the feed device comprises a feed apron which is located above the upper run of the second belt and which is fed through a feed pipe.

Claim 5

A filter as recited in claim 1, wherein the downstream end of the lower run of the second belt extends beyond the end of the upper run of the first belt.

Claim 6

A filter as recited in claim 1, wherein the second belt has a guide roller at the downstream end of its upper run and that guide roller is situated above the upper run of the first belt.

Claim 7

A filter as recited in claim 1, wherein the means for pressing together the first and second belts comprise sets of supporting rolls acting on the upper run of the first belt and the lower run of the second belt.

Claim 8

A filter as recited in claim 6, wherein in a first section of a path of contact of the belts, the supporting rollers on opposite sides of the belt are situated one above the other while in at least one second section they are staggered with respect to one another in a horizontal direction.

Claim 9

A filter as recited in claim 6, wherein the supporting rollers which are associated with the first belt are offset in relation to the supporting rollers associated with the second belt by an amount equal to one-half the distance between successive rollers, while in at least one first section of a path of contact between the belts the second belt and the first belt take a straight course, whereas in at least one further section, owing to the greater penetration of the supporting rollers, they take a zigzag course.

Claim 10

A filter as recited in claim 1, wherein a separate collecting trough is situated below the downstream section of a path of contact of the belts, and the discharge from that trough is led via a pump to the upper run of the second belt.

Claim 11

A filter as recited in claim 9, wherein the discharge from the pump is led to the feed device for the material to be deliquefied.

Claim 12

A filter as recited in claim 9, wherein the discharge from the pump is also led to a second feed device delivering on to the upper run of the second belt.

Claim 13

A filter as recited in claim 9, wherein a washing device is provided for delivering washing water to at least one of the belts, and wherein means is provided for collecting the washing water and feeding it to the pump.

Claim 14

A filter as recited in claim 1, wherein an absorbent material is pressed against pressed effluent emerging from between the first belt and the second belt.

Claim 15

A filter for removing liquid from a slurry, comprising: a. a first endless belt of filter fabric mounted on end rollers so as to form a horizontally-elongated loop having an upper run and a lower run, b. a second endless belt of filter fabric mounted on end rollers above the first belt so as to form a horizontally-elongated loop having an upper run and a lower run, c. means pressing the lower run of the second belt against the upper run of the first belt, d. a feed device situated at the upstream end of and above the upper run of the second belt, the material from the feed device eventually entering between the lower run of the second belt and the upper run of the first belt, which runs are driven in the same direction, and e. means associated with the upper run of the second endless belt to hold it substantially flat for conveying and preliminary draining of the newly-introduced slurry, wherein a separate collecting trough is situated below the downstream suction of a path of contact of the belts, and the discharge from that trough is led via a pump to the upper run of the second belt.

Claim 16

A filter for removing liquid from a slurry, comprising: a. a first endless belt of filter fabric mounted on end rollers so as to form a horizontally-elongated loop having an upper run and a lower run, b. a second endless belt of filter fabric mounted on end rollers above the first belt so as to form a horizontally-elongated loop having an upper run and a lower run, c. means pressing the lower run of the second belt against the upper run of the first belt, d. a feed device situated at the upstream end of and above the upper run of the second belt, the material from the feed device eventually entering between the lower run of the second belt and the upper run of the first belt, which runs are driven in the same direction, and e. means associated with the upper run of the second endless belt to hold it substantially flat for conveying and preliminary draining of the newly-introduced slurry, wherein a separate collecting trough is situated below the downstream suction of a path of contact of the belts, and the discharge from that trough is led via a pump to the upper run of the second belt.

Claim 17

A filter for removing liquid from a slurry, comprising: a. a first endless belt of the filter fabric forming a loop having a upper run and lower run, b. a second belt of filter fabric located above the first belt and forming a loop having an upper run and a lower run, c. means pressing the second belt against the first belt to form a pressure zone in which the belts are driven in the same direction, d. a feed device situated at the upstream end of and above the upper run of the second belt, the material from the feed device eventually entering a nip between the first and second belts, and passing through the pressure zone, and e. means underlying the upper run of the second endless belt to hold it substantially flat for conveying and preliminary draining of the newly-introduced slurry, the material being completely enclosed and carried by the belts all the way from the nip to the said pressure zone.

Claim 18

A filter for removing liquid from a slurry, comprising: a. a first endless belt of the filter fabric forming a loop having a upper run and lower run, b. a second belt of filter fabric located above the first belt and forming a loop having an upper run and a lower run, c. means pressing the second belt against the first belt to form a pressure zone in which the belts are driven in the same direction, d. a feed device situated at the upstream end of and above the upper run of the second belt, the material from the feed device eventually entering a nip between the first and second belts, and passing through the pressure zone, and e. means underlying the upper run of the second endless belt to hold it substantially flat for conveying and preliminary draining of the newly-introduced slurry, the material being completely enclosed and carried by the belts all the way from the nip to the said pressure zone.

Claim 19

A filter as recited in claim 15, wherein the feed device extends over the width of the second belt and transfers material to the second belt at a rate dependent on the speed of the belt, and wherein a pressure roller is provided having a perforated screen cylindrical surface, the roller being positioned at the downstream end of the upper run of the second belt, and pressing against that belt.

Claim 20

A filter as recited in claim 15, wherein the feed device comprises a feed apron which is located above the upper run of the second belt and which is fed through a feed pipe.

Claim 21

A filter as recited in claim 15, wherein the downstream end of the lower run of the second belt extends beyond the end of the upper run of the first belt.

Claim 22

A filter as recited in claim 15, wherein the second belt has a guide roller at the downstream end of its upper run and that guide roller is situated above the upper run of the first belt.

Claim 23

A filter as recited in claim 15, wherein the means for pressing together the first and second belts comprise sets of supporting rolls acting on the upper run of the first belt and the lower run of the second belt.

Claim 24

A filter as recited in claim 20, wherein in a first section of a path of contact of the belts, the supporting rollers on opposite sides of the belt are situated one above the other while in at least one second section they are staggered with respect to one another in a horizontal direction.

Claim 25

A filter as recited in claim 20, wherein the supporting rollers which are associated with the first belt are offset in relation to the supporting rollers associated with the second belt by an amount equal to one-half the distance between successive rollers, while in at least one first section of a path of contact between the belts the second belt and the first belt take a straight course, whereas in at least one further section, owing to the greater penetration of the supporting roller, they take a zigzag course.

Claim 26

A filter as recited in claim 15, wherein a separate collecting trough is situated below the downstream section of a path of contact of the belts, and the discharge from that trough is led via a pump to the upper run of the second belt.

Claim 27

A filter as recited in claim 23, wherein the discharge from the pump is led to the feed device for the material to be deliquefied.

Claim 28

A filter as recited in claim 23, wherein the discharge from the pump is also led to a second feed device delivering onto the upper run of the second belt.

Claim 29

A filter as recited in claim 23, wherein a washing device is provided for delivering washing water to at least one of the belts, and wherein means is provided for collecting the washing water and feeding it to the pump.

Claim 30

A filter as recited in claim 15, wherein an absorbent material is pressed against pressed effluent emerging from between the first belt and the second belt.