US4531892A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for pumping of pulp
Assignee: Valmet AB
•
Filing: 1984-02-07
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Granted: 1985-07-30
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Expires: 2004-02-07
Abstract
Abstract The apparatus comprises a centrifugal pump (1) fed by a screw feeder (8). The screw feeder comprises a screw (9) with a partially open thread (11). The screw (9) is driven separately in opposed direction to and with a lower speed than the impeller (3) of the pump (1). By this arrangement pulp of high concentration can be pumped.
Inventors
- 👤 Lars E. Nasman
- 👤 Alf I. Lindstrom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:34
CPC Classifications
F; F04; F04D; F04D7/00; F04D7/02; F04D7/04; B; B01; B01F; B01F33/00; B01F33/80; B01F33/82; F04D13/00; F04D13/12; Y; Y10; Y10S; Y10S417/00; Y10S417/90
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
138 words
An apparatus for pumping pulp of high concentration, comprising: a cenrifugal pump having a rotary impeller positioned between an inlet and an outlet of said pump, a screw conveyor mounted for rotation independently of said pump and including a screw arranged to advance pulp toward a discharge end of said screw conveyor, said discharge end being arranged in communication with said inlet of said pump, said screw comprising a partially open thread to permit a partial recirculation of the pulp, said screw having a transport capacity exceeding that of said pump, so that said partial recirculation of pulp is induced, the cross-sectional area of said discharge end of said screw conveyor being substantially greater than said pump inlet, means for rotating said pump impeller, and means for rotating said screw at a slower rate than said pump impeller.
Claim 2
Independent Claim
138 words
An apparatus for pumping pulp of high concentration, comprising: a cenrifugal pump having a rotary impeller positioned between an inlet and an outlet of said pump, a screw conveyor mounted for rotation independently of said pump and including a screw arranged to advance pulp toward a discharge end of said screw conveyor, said discharge end being arranged in communication with said inlet of said pump, said screw comprising a partially open thread to permit a partial recirculation of the pulp, said screw having a transport capacity exceeding that of said pump, so that said partial recirculation of pulp is induced, the cross-sectional area of said discharge end of said screw conveyor being substantially greater than said pump inlet, means for rotating said pump impeller, and means for rotating said screw at a slower rate than said pump impeller.
Claim 3
Dependent Claim
19 words
An apparatus as defined in claim 1, characterized in that the screw and impeller are driven in opposed directions.
Claim 4
Dependent Claim
26 words
An apparatus as defined in claim 2, characterized in that the thread of the screw is continuous and located spaced from the axle of the screw.
Claim 5
Dependent Claim
26 words
An apparatus as defined in claim 1, characterized in that the thread of the screw is continuous and located spaced from the axle of the screw.
References Cited (Backward Citations)
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Cited
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Cited
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-07-29 | 1989-01-28 | 1989-07-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-07-29 | 1993-01-28 | 1993-07-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-07-29 | 1997-01-28 | 1997-07-30 | $7700.00 | Window Closed / Lapsed |