US4571090A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mixing systems
Assignee: SAC Corp
•
Filing: 1985-08-26
•
Granted: 1986-02-18
•
Expires: 2005-08-26
Abstract
Abstract Mixing systems for liquids having fibers suspended therein wherein the fibers tenaciously adhere to and accumulate on the leading edge of the impeller, thereby increasing the drag of the liquid on the impeller as it rotates and the consequent increase in the power required to rotate the impeller. Axial flow of the liquid in a tank is produced by the impeller within a draft tube. The leading edge of the blades of the impeller are inclined with respect to radial lines extending from the axis of rotation of the impeller beyond the angle of repose of the fibers on the leading edge. Also, the coefficient of friction of the portion of the impeller, extending from the leading edge toward the trailing edge thereof, to which the fibers adhere is reduced by providing the surface thereof with a low coefficient of friction material.
Inventors
- 👤 Ronald J. Weetman
- 👤 Jerry A. Carpenter
- 👤 Chandler K. Coyle
- 👤 Keith T. McDermott
- 👤 Roger N. Voss
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 05:34
CPC Classifications
B; B01; B01F; B01F27/00; B01F27/05; B01F27/11; B01F27/113; B01F33/00; B01F33/86; B01F33/862
Claims Analysis
Total Claims: 42
Claim 1
Independent Claim
171 words
Apparatus for circulating liquids having fibers suspended therein in a region containing said liquids which comprises a draft tube disposed in said region containing said liquids, a shaft, an axial flow impeller having a plurality of blades, said impeller being disposed in said draft tube on said shaft, said shaft and said impeller being coaxial with said tube, said blades having opposite edges one of which leads the other as said impeller rotates, said leading edges being inclined with respect to radial lines from the axis of said impeller in planes perpendicular to said axis at angles greater than the angle of repose of said fibers on said impeller as said impeller rotates through said liquids and said liquids flow in the direction axially of said impeller through said draft tube thereby preventing the accumulation of said fibers on said leading edge and the increase of drag on said impeller which prevents the rotation thereof at sufficient speed to circulate said liquids without increasing the power applied to rotate said shaft.
Claim 2
Dependent Claim
171 words
Apparatus for circulating liquids having fibers suspended therein in a region containing said liquids which comprises a draft tube disposed in said region containing said liquids, a shaft, an axial flow impeller having a plurality of blades, said impeller being disposed in said draft tube on said shaft, said shaft and said impeller being coaxial with said tube, said blades having opposite edges one of which leads the other as said impeller rotates, said leading edges being inclined with respect to radial lines from the axis of said impeller in planes perpendicular to said axis at angles greater than the angle of repose of said fibers on said impeller as said impeller rotates through said liquids and said liquids flow in the direction axially of said impeller through said draft tube thereby preventing the accumulation of said fibers on said leading edge and the increase of drag on said impeller which prevents the rotation thereof at sufficient speed to circulate said liquids without increasing the power applied to rotate said shaft.
Claim 3
Dependent Claim
48 words
The apparatus according to claim 1 wherein the angles between the ones of said radial lines which intersects said leading edges where said one radial lines are 70% of the radius from the axis of said impeller to the tips of said blades are from 20° to 60°.
Claim 4
Dependent Claim
55 words
The apparatus according to claim 2 further comprising a hub on said shaft, said blades being connected to said hub, the portions of said leading edges of said blades adjacent to said hub being along an arcuate curve and the remainder of said leading edges between said tip and said portions being along straight lines.
Claim 5
Dependent Claim
25 words
The invention according to claim 3 wherein said angles between said one radial lines and said straight line portions of said blades is about 40°.
Claim 6
Dependent Claim
55 words
The apparatus according to claim 2 wherein said trailing edges of said blades define angles with radial lines from the axis of said impeller in planes perpendicular thereto which intersects said trailing edges which last named angles are smaller than said angles between said leading edges and said radial lines which intersect said leading edges.
Claim 7
Dependent Claim
14 words
The apparatus according to claim 5 wherein said trailing edges are along straight lines.
Claim 8
Dependent Claim
13 words
The apparatus according to claim 2 wherein said blades have airfoil cross-sectional profiles.
Claim 9
Dependent Claim
15 words
The apparatus according to claim 7 wherein said blades have camber, thickness distribution and twist.
Claim 10
Dependent Claim
76 words
The apparatus according to claim 8 wherein said camber has a length from about 4% to 8% of the length of the chord of said blades between said leading and trailing edges thereof and said maximum thickness is from 6% to 12% of said chord length, and wherein the angle between said chord and planes perpendicular to said axis is greater adjacent to said hub than adjacent to said tips of said blades and varies therebetween.
Claim 11
Dependent Claim
49 words
The apparatus according to claim 2 further comprising a hub connecting said blades to said shaft and wherein said leading edges are arcuate from the tips of said blades to said hub, said angles to said radial lines being between tangents to said leading edge and said radial lines.
Claim 12
Dependent Claim
15 words
The apparatus according to claim 10 wherein said leading edges are along sectors of circles.
Claim 13
Dependent Claim
45 words
The apparatus according to claim 11 wherein the sectors of said leading edges have their centers along lines perpendicular to lines tangent to said leading edges where said radial lines are 70% of the radius of said blades from said axis to the tips thereof.
Claim 14
Dependent Claim
47 words
The apparatus according to claim 12 wherein said trailing edges of each of said blades are sectors of circles the one of which adjacent to said hub having the same center as the leading edge thereof and the other of which sectors has its center inwardly thereof.
Claim 15
Dependent Claim
13 words
The apparatus according to claim 10 wherein said trailing edges are also arcuate.
Claim 16
Dependent Claim
39 words
The apparatus according to claim 1 wherein said blades have opposite surfaces portions of which extending from said leading edges to said trailing edges are of material having lower coefficient of friction than the remainder of said blade surfaces.
Claim 17
Dependent Claim
26 words
The apparatus according to claim 15 wherein said portions extend about 10% of the length of said surfaces from said leading to said trailing edges thereof.
Claim 18
Dependent Claim
22 words
The apparatus according to claim 16 wherein said portions are provided by inserts which define said leading edges and provide said surfaces.
Claim 19
Dependent Claim
14 words
The apparatus according to claim 17 wherein said material of said inserts is plastic.
Claim 20
Dependent Claim
23 words
The apparatus according to claim 18 wherein said plastic material is selected from the group consisting of high molecular weight polyethylene and fluoropolymers.
Claim 21
Dependent Claim
152 words
Apparatus for circulating liquids having fibers suspended therein in a region containing said liquids which comprises a shaft in said region containing said liquids, an axial flow impeller having a plurality of blades, said impeller being disposed in said tank on said shaft, said blades having opposite edges one of which leads the other as said impeller rotates, said leading edges being inclined with respect to radial lines from the axis of said impeller in planes perpendicular to said axis at angles greater than the angle of repose of said fibers on said impeller as said impeller rotates through said liquids and said liquids flow in the direction axially of said impeller thereby preventing the accumulation of said fibers on said leading edge and the increase of drag on said impeller which prevents the rotation thereof at sufficient speed to circulate said liquids without increasing the power applied to rotate said shaft.
Claim 22
Dependent Claim
152 words
Apparatus for circulating liquids having fibers suspended therein in a region containing said liquids which comprises a shaft in said region containing said liquids, an axial flow impeller having a plurality of blades, said impeller being disposed in said tank on said shaft, said blades having opposite edges one of which leads the other as said impeller rotates, said leading edges being inclined with respect to radial lines from the axis of said impeller in planes perpendicular to said axis at angles greater than the angle of repose of said fibers on said impeller as said impeller rotates through said liquids and said liquids flow in the direction axially of said impeller thereby preventing the accumulation of said fibers on said leading edge and the increase of drag on said impeller which prevents the rotation thereof at sufficient speed to circulate said liquids without increasing the power applied to rotate said shaft.
Claim 23
Dependent Claim
48 words
The apparatus according to claim 20 wherein the angles between the ones of said radial lines which intersects said leading edges where said one radial lines are 70% of the radius from the axis of said impeller to the tips of said blades are from 20° to 60°.
Claim 24
Dependent Claim
55 words
The apparatus according to claim 21 further comprising a hub on said shaft, said blades being connected to said hub, the portions of said leading edges of said blades adjacent to said hub being along an arcuate curve and the remainder of said leading edges between said tip and said portions being along straight lines.
Claim 25
Dependent Claim
25 words
The invention according to claim 22 wherein said angles between said one radial lines and said straight line portions of said blades is about 40°.
Claim 26
Dependent Claim
55 words
The apparatus according to claim 21 wherein said trailing edges of said blades define angles with radial lines from the axis of said impeller in planes perpendicular thereto which intersects said trailing edges which last named angles are smaller than said angles between said leading edges and said radial lines which intersect said leading edges.
Claim 27
Dependent Claim
14 words
The apparatus according to claim 24 wherein said trailing edges are along straight lines.
Claim 28
Dependent Claim
13 words
The apparatus according to claim 21 wherein said blades have airfoil cross-sectional profiles.
Claim 29
Dependent Claim
15 words
The apparatus according to claim 26 wherein said blades have camber, thickness distribution and twist.
Claim 30
Dependent Claim
76 words
The apparatus according to claim 27 wherein said camber has a length from about 4% to 8% of the length of the chord of said blades between said leading and trailing edges thereof and said maximum thickness is from 6% to 12% of said chord length, and wherein the angle between said chord and planes perpendicular to said axis is greater adjacent to said hub than adjacent to said tips of said blades and varies therebetween.
Claim 31
Dependent Claim
49 words
The apparatus according to claim 21 further comprising a hub connecting said blades to said shaft and wherein said leading edges are arcuate from the tips of said blades to said hub, said angles to said radial lines being between tangents to said leading edge and said radial lines.
Claim 32
Dependent Claim
15 words
The apparatus according to claim 29 wherein said leading edges are along sectors of circles.
Claim 33
Dependent Claim
13 words
The apparatus according to claim 30 wherein said trailing edges are also arcuate.
Claim 34
Dependent Claim
45 words
The apparatus according to claim 30 wherein the sectors of said leading edges have their centers along lines perpendicular to lines tangent to said leading edges where said radial lines are 70% of the radius of said blades from said axis to the tips thereof.
Claim 35
Dependent Claim
47 words
The apparatus according to claim 32 wherein said trailing edges of each of said blades are sectors of circles the one of which adjacent to said hub having the same center as the leading edge thereof and the other of which sectors has its center inwardly thereof.
Claim 36
Dependent Claim
39 words
The apparatus according to claim 20 wherein said blades have opposite surfaces portions of which extending from said leading edges to said trailing edges are of material having lower coefficient of friction than the remainder of said blade surfaces.
Claim 37
Dependent Claim
26 words
The apparatus according to claim 34 wherein said portions extend about 10% of the length of said surfaces from said leading to said trailing edges thereof.
Claim 38
Dependent Claim
22 words
The apparatus according to claim 35 wherein said portions ar provided by inserts which define said leading edges and provide said surfaces.
Claim 39
Dependent Claim
14 words
The apparatus according to claim 36 wherein said material of said inserts is plastic.
Claim 40
Dependent Claim
23 words
The apparatus according to claim 37 wherein said plastic material is selected from the group consisting of high molecular weight polyethylene and fluoropolymers.
Claim 41
Dependent Claim
15 words
The apparatus according to claim 1 wherein said region containing said liquids is a tank.
Claim 42
Dependent Claim
15 words
The apparatus according to claim 20 wherein said region containing said liquids is a tank.
References Cited (Backward Citations)
US1293381A
Cited
US1981392A
Cited
GB427190A
Cited
US2592876A
Cited
US3174313A
Cited
US3367423A
Cited
US3499633A
Cited
US3477382A
Cited
US3564651A
Cited
US4147437A
Cited
US4135858A
Cited
DE2844113A1
Cited
US4231974A
Cited
US4240990A
Cited
US4358206A
Cited
EP0078660A2
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-02-17 | 1989-08-19 | 1990-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-17 | 1993-08-19 | 1994-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-17 | 1997-08-19 | 1998-02-18 | $7700.00 | Window Closed / Lapsed |