US4986480A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for feeding a conical refiner
Assignee: Metso Fiber Karlstad AB
•
Filing: 1989-06-29
•
Granted: 1991-01-22
•
Expires: 2009-06-29
Abstract
Abstract Mechanical cellulosic fibrous material pulp (mechanical pulp to produce paper products) having lower freeness, and enhanced light scattering properties, tensile and tear strengths, for a given energy input, is produced by force feeding a refiner. Using a progressive compacting plugscrew, cellulosic material (e.g. wood chips) is fed to the refiner inlet at a rate greater than the transporting capacity of the refiner (e.g. about 10-40% greater). The refiner preferably is a low frequency conical refiner with steam removal at the grinding area between the conical refiner elements. The production rate is regulated by sensing the axial force on the refiner rotor and controlling the spacing between the refiner elements in response to the sensed axial force. The screw has a compaction ratio of at least 3/1 for wood chips and 6/1 for pulp, and is rotated at about 6-10% the speed of rotation of the refiner rotor.
Inventors
- 👤 Johan Gullichsen
- 👤 Bengt Nilsson
- 👤 Ronny Hoglund
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:36
CPC Classifications
D; D21; D21B; D21B1/00; D21B1/04; D21B1/12; D21B1/14; D21B1/26; D21D; D21D1/00; D21D1/20; D21D1/22
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
112 words
Apparatus for producing pulp from cellulosic fibrous material comprising: (a) a mechanical refiner having at least two relatively movable refining elements, and a rotor shaft connected to one of said elements, a material inlet, and a pulp outlet, and a given transporting capacity; and (b) means for force feeding said refiner inlet with material at a rate greater than the transporting capacity of said refiner, and forming a plug of material at the refiner inlet which substantially prevents passage of steam therethrough, said force feeding means comprising a progressive compacting plug screw having a blank portion on the screw at the most narrow portion of the surrounding housing, immediately adjacent the refiner.
Claim 2
Dependent Claim
112 words
Apparatus for producing pulp from cellulosic fibrous material comprising: (a) a mechanical refiner having at least two relatively movable refining elements, and a rotor shaft connected to one of said elements, a material inlet, and a pulp outlet, and a given transporting capacity; and (b) means for force feeding said refiner inlet with material at a rate greater than the transporting capacity of said refiner, and forming a plug of material at the refiner inlet which substantially prevents passage of steam therethrough, said force feeding means comprising a progressive compacting plug screw having a blank portion on the screw at the most narrow portion of the surrounding housing, immediately adjacent the refiner.
Claim 3
Dependent Claim
27 words
Apparatus as recited in claim 1 wherein said progressive compacting plugscrew has a compaction of at least 6/1 for pulp and at least 3/1 for wood chips.
Claim 4
Dependent Claim
37 words
Apparatus as recited in claim 2 further comprising a first motor for rotating the refiner rotor shaft, and a second motor for rotating the screw at about 6-10% the speed of rotation of the refiner rotor shaft.
Claim 5
Dependent Claim
37 words
Apparatus as recited in claim 2 wherein said refiner is a conical refiner, said refining elements being conical and extending outwardly and away from said inlet, said inlet being centrally located at the axis of said shaft.
Claim 6
Dependent Claim
43 words
Apparatus as recited in claim 4 further comprising (c) means for adjusting the spacing between said refining elements, (d) means for sensing the axial force on said rotor shaft, and (e) means for controlling (c) in response to the sensed force utilizing (d).
Claim 7
Dependent Claim
26 words
Apparatus as recited in claim 4 wherein (a) is a low frequency refiner with steam removal means within an actual grinding area between said refiner elements.
Claim 8
Dependent Claim
22 words
Apparatus as recited in claim 6 wherein (a) includes a centrifugal separator associated with said rotor for centrifugally separating steam and fibers.
Claim 9
Dependent Claim
43 words
Apparatus as recited in claim 1 further comprising (c) means for adjusting the spacing between said refining elements, (d) means for sensing the axial force on said rotor shaft, and (e) means for controlling (c) in response to the sensed force utilizing (d).
Claim 10
Dependent Claim
37 words
Apparatus as recited in claim 1 wherein said refiner is a conical refiner, said refining elements being conical and extending outwardly and away from said inlet, said inlet being centrally located at the axis of said shaft.
Claim 11
Dependent Claim
26 words
Apparatus as recited in claim 1 wherein (a) is a low frequency refiner with steam removal means within an actual grinding area between said refiner elements.
Claim 12
Dependent Claim
35 words
Apparatus as recited in claim 2 wherein said progressive compacting plug screw includes a screw within a surrounding housing defining a central opening tapered to a most narrow point, with a screw within said opening.
Claim 13
Independent Claim
75 words
A method of refining cellulosic fibrous material to produce mechanical pulp, using a mechanical refiner having an inlet and a given transporting capacity, comprising the step of: (a) force feeding the refiner with cellulosic fibrous material at a rate greater than the transporting capacity of the refiner, including by feeding the material into the inlet with a progressive compacting screw so that passage of steam out of the refiner through the inlet is substantially prevented.
Claim 14
Independent Claim
75 words
A method of refining cellulosic fibrous material to produce mechanical pulp, using a mechanical refiner having an inlet and a given transporting capacity, comprising the step of: (a) force feeding the refiner with cellulosic fibrous material at a rate greater than the transporting capacity of the refiner, including by feeding the material into the inlet with a progressive compacting screw so that passage of steam out of the refiner through the inlet is substantially prevented.
Claim 15
Dependent Claim
63 words
A method as recited in claim 12 wherein the refiner has a rotor shaft and at least two refiner elements, one of which is connected to the rotor shaft, and comprising the further step of: (b) regulating production of mechanical pulp by sensing the axial force on the rotor shaft and controlling the spacing between the refiner elements in response to this sensing.
Claim 16
Dependent Claim
58 words
A method as recited in claim 12 wherein step (a) is practiced so that the rate of feed compared to transporting capacity of the refiner so that for a given amount of energy, the pulp produced will have a lower freeness, greater light scattering coefficient, and greater tensile strength than pulp produced without force feeding of the refiner.
Claim 17
Dependent Claim
29 words
A method as recited in claim 12 wherein step (a) is practiced by feeding the refiner at a rate about 10-40% greater than the transporting capacity of the refiner.
Claim 18
Dependent Claim
33 words
A method as recited in claim 15 wherein the refiner has a rotor, and is fed by a screw which is rotated at about 6-10% the speed of rotation of the refiner rotor.
Claim 19
Dependent Claim
32 words
A method as recited in claim 12 wherein step (a) is practiced using a screw having a compaction ratio of at least 3/1 for wood chips, and at least 6/1 for pulp.
References Cited (Backward Citations)
US2573321A
Cited
US3327952A
Cited
US4059237A
Cited
US4082233A
Cited
US4457804A
Cited
CA1079559A
Cited
US4283016A
Cited
US4401280A
Cited
US4700900A
Cited
US4801099A
Cited
US4754935A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-01-21 | 1994-07-23 | 1995-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-21 | 1998-07-23 | 1999-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-21 | 2002-07-23 | 2003-01-22 | $7700.00 | Window Closed / Lapsed |