US4275852A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for controlling the refining of fibrous pulp grist in a drum refiner
Assignee: Individual
•
Filing: 1979-08-20
•
Granted: 1981-06-30
•
Expires: 1999-08-20
Abstract
Abstract Apparatus for controlling the refining of fibrous lignocellulosic pulp in a drum refiner in which the pulp stock, or grist, is conveyed into a cylindrical stationary drum and propelled therein in a linear direction in a pulsating fashion by a co-axial rotor comprising a plurality of wings which attack the grist in a wedging action as it is pushed ahead of the leading faces of the wings and which induce in the grist internal frictional shear forces while it is forced through a gap defined between the leading edges of the wings and a series of shear means arranged axially along the interior surface of the stationary drum. The process is controlled by coordinating the angle of attack on the grist by the wings and corresponding variations in the gap clearance with the energy demands or mechanical power input.
Inventors
- 👤 Arne J. A. Asplund
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 01:49
CPC Classifications
D; D21; D21D; D21D1/00; D21D1/20; D21D1/34; D21D1/38; D21D1/002
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
156 words
In a drum refiner for refining pulp stock, in which the pulp grist is conveyed into a stationary cylindrical drum and propelled in a linear direction therein by a co-axial rotor comprising a plurality of wings having a leading face and a trailing face which attack the grist at an angle in a wedging action as its is pushed ahead by the leading face of the wing in a pulsating fashion to induce in the grist internal frictional shear forces while being squeezed through a gap clearance defined between the free end of the wings and shear means arranged axially along the interior cylindrical wall surface of the stationary drum, the improvement comprising: blade means mounted adjustably along a surface of said wings so as to be deflected at an angle thereto and effective simultaneously to coordinate the angle of attack on the grist and the gap clearance variations in energy demand during the refining process.
Claim 2
Dependent Claim
156 words
In a drum refiner for refining pulp stock, in which the pulp grist is conveyed into a stationary cylindrical drum and propelled in a linear direction therein by a co-axial rotor comprising a plurality of wings having a leading face and a trailing face which attack the grist at an angle in a wedging action as its is pushed ahead by the leading face of the wing in a pulsating fashion to induce in the grist internal frictional shear forces while being squeezed through a gap clearance defined between the free end of the wings and shear means arranged axially along the interior cylindrical wall surface of the stationary drum, the improvement comprising: blade means mounted adjustably along a surface of said wings so as to be deflected at an angle thereto and effective simultaneously to coordinate the angle of attack on the grist and the gap clearance variations in energy demand during the refining process.
Claim 3
Dependent Claim
33 words
A drum refiner according to claim 1, in which blade means are mounted on said wings so as to permit the free ends thereof to be deflected at an angle to the wings.
Claim 4
Dependent Claim
34 words
A drum refiner according to claim 1, in which the blade means are deflected by hydraulic means carried by the wings and controlled in response to variations in energy demands during the refining process.
Claim 5
Dependent Claim
44 words
A drum refiner according to claim 3, in which the rotor comprises a plurality of wing-equipped sections, each section being separately controlled by the hydraulic means in response to localized variations in energy demands along the linear route of the grist through the drum.
Claim 6
Dependent Claim
36 words
A drum refiner according to claim 1, in which the wings comprise an inner portion and an outer portion which extends at an angle to said inner portion and which outer portion supports said blade means.
References Cited (Backward Citations)
US1951519A
Cited
US3806050A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-06-29 | 1984-12-29 | 1985-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-06-29 | 1988-12-29 | 1989-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-06-29 | 1992-12-29 | 1993-06-30 | $7700.00 | Window Closed / Lapsed |