Pulp refining system and process

Claim 2

A process as in claim 2 characterized by limiting the time interval of said raw material in said refining segment of the pulping system to a period of from approximately 1/2 minute to about 2 minutes.

Claim 3

A process as in claim 3 characterized by limiting the conditioning interval to about 1 minute.

Claim 4

A pulp refining process comprising the steps of maintaining a refining segment of a pulping system under seal, establishing therein an elevated pressure under 50 p.s.i.g., moving through said segment, in the initial portion thereof, raw fibrous material substantially exclusive of attendant liquid except that contained in the body thereof, during said movement subjecting said material to a conditioning fluid in a substantially gaseous state under conditions which inhibit addition to the moisture content of said raw material, and in the final portion of said refining segment subjecting the raw material, which is still maintained substantially exclusive of attendant liquid except for its moisture content, to a separating action under the influence of opposed refining surfaces, one of which rotates relative the other, to produce elongate fibers and fiber bundles wherein outer surface portions are roughened to break their wall structure, said process as applied to wood and like substance in the form of chips, shavings and sawdust separating the raw materials so as to produce in the separated fibers irregularities of a nature to expose their microfibrillar surface which is rich in cellulose, continuously forwarding the fiber discharge from said first mentioned refining segment to a second refining segment and further refining therein the fiber discharge under atmospheric pressure condition to produce elongate, soft, strong fibers having a tendency to interlace and interlock, in the process of forwarding the fiber discharge to said second refining segment cooling and quenching the same, and in said second refining segment subjecting the cooled product to atmospheric refining between double revolving opposed refining surfaces.

Claim 5

A pulp refining process comprising the steps of maintaining a refining segment of a pulping system under seal, establishing therein an elevated pressure under 50 p.s.i.g., moving through said segment, in the initial portion thereof, raw fibrous material substantially exclusive of attendant liquid except that contained in the body thereof, during said movement subjecting said material to a conditioning fluid in a substantially gaseous state under conditions which inhibit addition to the moisture content of said raw material, in the final portion of said refining segment subjecting the raw material, which is still maintained substantially exclusive of attendant liquid except for its moisture content, to a separating action under the influence of opposed refining surfaces, one of which rotates relative the other to produce elongated fibers and fiber bundles wherein outer surface portions are roughened to break their wall structure, and mechanically loOsening the fibers of the raw material prior to said refining segment.

Claim 6

A process as in claim 6 characterized by introducing conditioning fluid in the body of the raw material having loosened fibers to the extent it will accommodate the same, immediately prior to the said refining segment, and inhibiting in the process free liquid attending the raw material in moving to and between the opposed refining surfaces.

Claim 8

A system as in claim 8 characterized by said weakening means including steam delivery means for establishing in said pressurized segment a pressure not greater than 50 p.s.i.g. and a correspondingly moderate elevated temperature.

Claim 9

A system as in claim 9 characterized by an initial portion of said feeding means including means for pressing and squeezing said raw material to partially loosen the bond between fibers thereof prior to the material entering said pressurized segment and moving to and between the double revolving discs therein, thereby providing in part said weakening means.

Claim 10

A system as in claim 9 characterized by means connected to said pressurized segment for mechanically loosening fibers of said raw material prior to entering said pressurized segment and applying in the body of said material conditioning fluid in a manner to inhibit the creation of free liquid attendant the raw material as fed to said pressurized segment.

Claim 11

A system as in claim 8 characterized in that the double revolving discs of said refiner are opposed and have the operating surfaces thereof spaced apart a distance not greater than about 0.040 inches.

Claim 12

A system as set forth in claim 12 characterized by said operating surfaces being spaced apart a distance between about 0.005 to 0.040 inches.

Claim 13

A system as set forth in claim 8 and including means for quenching and cooling the fiber products issuing from said pressurized segment prior to direct exposure thereof to atmosphere.

Claim 14

A system as set forth in claim 14 characterized by said quenching and cooling means being embodied in a cyclone separator in connection with said double revolving disc refiner to receive its discharge, said quenching and cooling means being positioned at the entrance to said cyclone separator.

Claim 15

A system as set forth in claim 15 characterized by said quenching and cooling means being arranged to direct fluid directly across the inflow of the discharge from said double revolving disc refiner to said cyclone separator.

Claim 16

A system as set forth in claim 16 characterized by at least one atmospheric double revolving disc refiner connected with said cyclone to receive the fiber products discharge therefrom and to apply thereto a secondary atmospheric refining whereby to produce elongate strong fibers having a tendency to interlace and interlock and to achieve a reduced bulk form.

Claim 17

Apparatus as set forth in claim 17 characterized by a second atmospheric double revolving disc refiner in series connection with said secondary refiner.

Claim 18

Apparatus as set forth in claim 18 and mechanical means forming part of said feeding means for loosening fibers of the raw material prior to disc refining.

Claim 19

A pulp refining system comprising means for conditioning raw fibrous material to only partially Weaken the agents which bond its fibers, further means to act thereon to reduce the same to elongate fibers and fiber bundles and means to control the pressure of the environment of said conditioning and refining means providing that said fibers and fiber bundles issue from said refiner with surface portions thereof lamellated and fibrillated.

Claim 20

A pulp refining process comprising the steps of defining a closed refiner segment including a treatment chamber and beyond said chamber a disc refiner comprised of opposed counter rotating double discs, putting raw fibrous material through said segment first through said chamber and then between the discs of said double disc refiner, admitting steam to said segment to maintain pressure and temperature conditions therein of such elevation to be insufficient to irreversibly change the nature of the bonding agent in the raw materials and in the case of wood to produce a limited degree of softening of the lignin content, cooling the fibrous material after its discharge from said refiner, and establishing a brevity of time and closed condition of confinement of the fibrous material in its movement through said segment and to and through said cooling step to obviate degradation of the material fibers and their brightness.

Claim 21

A pulp refining process according to Claim 21 wherein the opposed discs are set to define a clearance therebetween on the order of 0.005 inches to 0.040 inches.

Claim 22

A pulp refining process according to claim 21 wherein the step of defining a closed refiner segment includes the provision of valves at opposite ends of said segment, at least one of said valves being a rotary valve containing supply pockets communicating successively with said segment in response to rotation of the valve.

Claim 23

A pulp refining process according to claim 23 wherein said rotary valve is positioned at an input end of said refiner segment intermediate said segment and a supply bin containing dry raw fibrous material, further characterized by the steps of utilizing pressure fluid to scavenge pockets of said rotary valve after communicating with said segment and of returning scavenged material to said supply bin under conditions inherently separating pressure fluid from the returned material and discharging separated pressure fluid away from said supply bin.

Claim 24

A pulp refining process according to claim 21 wherein the pressure in said refiner segment is maintained at about 30 p.s.i.g. with a corresponding temperature of about 135* C.

Claim 25

A pulp refining process according to claim 21 wherein the step of cooling refined material is carried out in a centrifugal separator disposed beyond said refiner segment and to which material discharged from said refiner is conducted under conditions excluding the refined material from atmospheric contact, a substantial separation of fluids from the refined fibrous material occurring in said separator.

Claim 26

A pulp refining process according to claim 26 wherein cooling is effected by spraying liquid into the centrifugal separator at a location substantially to intersect the path of incoming fibrous material discharging from said refiner.

Claim 27

A pulp refining process according to claim 21, characterized by the step in said double disc refiner of breaking and fibrillating surface portions of the natural fibers in said fibrous material.

Claim 28

A pulp refining system, comprising means defining a closed refiner segment including a treatment chamber and beyond said chamber a disc refiner having opposed counter rotating double discs, means for putting raw fibrous material through said segment first through said chamber and then between the discs of said double disc refiner, means for admitting steam to said segment to maintain pressure and temperature conditions therein of such elevation to be insufficient to irreversibly change the nature of the bonding agent in the raw materials and in the case of wood to produce a limited degree of softening of the lignin Content, means for cooling the fibrous material after its discharge from said refiner, means establishing a brevity of time and closed condition of confinement of the fibrous material in its movement through said segment and to and through said cooling step to obviate degradation of the material fibers and their brightness, and means operable in the double disc refiner to break and fibrillate surface portions of the natural fibers in said fibrous material.

Claim 29

A pulp refining process according to claim 26, characterized by the step of subjecting cooled separated fibrous material discharging from said centrifugal separator to additional refining under conditions of open atmospheric communication.