US4789433A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Skimming blade with wave shaped troughs for a papermaking machine
Assignee: Feldmuehle AG
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Filing: 1986-04-11
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Granted: 1988-12-06
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Expires: 2006-04-11
Abstract
Abstract Skimming blades in papermaking machines have a dewatering surface 4 adjoining the supporting surface 3 supporting the wire 1. To sustain the desired microturbulence of the fiber suspension 2 on the wire 1, the dewatering surface 4 is provided with troughs 7. The troughs 7 have a wavy shape, in which the wave crests 5 have a smaller radius r than the wave valleys 6.
Inventors
- 👤 Karl-Dieter Fuchs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 03:06
CPC Classifications
D; D21; D21F; D21F1/00; D21F1/18; D21F1/20; D21F1/48; D21F1/483
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
116 words
A skimming blade for removing water from a fiber slurry on a moving wire, having a direction of travel, of a papermaking machine, comprising a blade having a supporting surface to support the wire and run substantially paprallel to the wire, which is adjoined by at least one dewatering surface serving for vacuum dewatering, said dewatering surface being inclined with respect to the supporting surface by an angle of 5 to 360 minutes and having a plurality of troughs which extend at an angle of 90 to 5 degrees to an imaginary extension line of the supporting surface at a level of an envelope line of the dewatering surface without passing downward through the skimming blade.
Claim 2
Dependent Claim
116 words
A skimming blade for removing water from a fiber slurry on a moving wire, having a direction of travel, of a papermaking machine, comprising a blade having a supporting surface to support the wire and run substantially paprallel to the wire, which is adjoined by at least one dewatering surface serving for vacuum dewatering, said dewatering surface being inclined with respect to the supporting surface by an angle of 5 to 360 minutes and having a plurality of troughs which extend at an angle of 90 to 5 degrees to an imaginary extension line of the supporting surface at a level of an envelope line of the dewatering surface without passing downward through the skimming blade.
Claim 3
Dependent Claim
20 words
The skimming blade of claim 1 wherein the dewatering surface has an Ra value of from 0.5 to 10.0 micrometers.
Claim 4
Dependent Claim
21 words
The skimming blade of claim 1 wherein each of the plurality of troughs has a cross section having a wave shape.
Claim 5
Dependent Claim
43 words
The skimming blade of claim 3 wherein the wave shape cross section has wave crests of a radius r and wave valleys of a radius R, the radius r of the wave crests being smaller than the radius R of the wave valleys.
Claim 6
Dependent Claim
22 words
The skimming blade of claim 4 wherein r is from 0.5 to 20 mm and R is from 1 to 50 mm.
Claim 7
Dependent Claim
26 words
The skimming blade of claim 4 wherein the distance between two adjacent troughs is equal to or greater than five times r of the wave crests.
Claim 8
Dependent Claim
27 words
The skimming blade of claim 4 wherein r of the wave crest and/or R of the wave valley increase in size in the direction of wire travel.
Claim 9
Dependent Claim
31 words
The skimming blade of claim 3 wherein a convex-concave curve, which merges with the waves of the plurality of troughs, forms a step between the supporting surface and the dewatering surface.
Claim 10
Dependent Claim
20 words
The skimming blade of claim 1 wherein the distance between individual adjacent troughs increases in the direction of wire travel.
Claim 11
Dependent Claim
25 words
The skimming blade of claim 1 wherein the dewatering surface has a width which amounts to three to twenty times that of the supporting surface.
Claim 12
Dependent Claim
36 words
The skimming blade of claim 1 wherein between the supporting surface and the envelope line drawn across the apexes of the troughs, there is a free space of a height of from 0.1 to 10 mm.
Claim 13
Dependent Claim
13 words
The skimming blade of claim 11 wherein the envelope line is a curve.
Claim 14
Dependent Claim
34 words
The skimming blade of claim 11 wherein each of the plurality of troughs has a depth of 2.5% to 70% of the thickness of the skimming blade in the area of the dewatering surface.
References Cited (Backward Citations)
CA699193A
Cited
US3496064A
Cited
FR2012871A1
Cited
US3573159A
Cited
DE2337676A1
Cited
US4123322A
Cited
EP0078406A2
Cited
GB2113264A
Cited
DE3316708A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-12-06 | 1992-06-06 | 1992-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-06 | 1996-06-06 | 1996-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-06 | 2000-06-06 | 2000-12-06 | $7700.00 | Window Closed / Lapsed |