EP0158048A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Mixing systems
Assignee: SPX Technologies Inc
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Filing: 1985-02-15
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Granted: —
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Expires: 2005-02-15
Abstract
Abstract @ Mixing systems for liquids having fibers suspended therein wherein the fibers tenaciously adhere to and accumulate on the leading edge of an impeller (30), thereby increasing the drag of the liquid on the impeller (30) as it rotates and the consequent increase in the power required to rotate the impeller (30), is reduced. Axial flow of the liquid in a tank (10) is produced by the impeller (30) within a draft tube (12). The leading edge (38) of the blades (32) of the impeller (30) are inclined with respect to radial lines (60) extending from the axis of rotation (56) of the impeller (30) beyond the angle of repose of the fibers on the leading edge (38). Also, the coefficient of friction of the portion of the impeller (30), extending from the leading edge (38) toward the trailing edge (40) thereof, to which the fibers adhere is reduced by providing the surface thereof with a low coefficient of friction material (50).
Inventors
- 👤 Ronald J. Weetman
- 👤 Jerry A. Carpenter
- 👤 Chandler K. Coyle
- 👤 Keith T. Mcdermott
- 👤 Roger N. Voss
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 16:23
CPC Classifications
B; B01; B01F; B01F27/00; B01F27/80; B01F27/91; B01F27/05; B01F27/11; B01F27/113; B01F33/00; B01F33/86; B01F33/862
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
98 words
The method of mixing in a tank liquids containing fibers suspended therein with the aid of an impeller having opposite edges which respectively lead and trail each other as said impeller rotates, which comprises the steps of circulating said liquid through said tank (10) along a flow path which extends axially of said impeller (30), and decreasing the adhesion of said fibers along the leading edge (38) of said impeller (30) thereby preventing increased drag and reduced lift on said impeller (30) due to accumulation of said fibers on said leading edge (38) as said impeller (30) rotates.
Claim 2
Independent Claim
98 words
The method of mixing in a tank liquids containing fibers suspended therein with the aid of an impeller having opposite edges which respectively lead and trail each other as said impeller rotates, which comprises the steps of circulating said liquid through said tank (10) along a flow path which extends axially of said impeller (30), and decreasing the adhesion of said fibers along the leading edge (38) of said impeller (30) thereby preventing increased drag and reduced lift on said impeller (30) due to accumulation of said fibers on said leading edge (38) as said impeller (30) rotates.
Claim 3
Dependent Claim
61 words
The method according to claim 1, wherein said adhesion is decreased by use of an impeller (30) modified by inclining said leading edge (38) with respect to radial lines (60) extending perpendicularly from the axis (56) of said impeller (30) sufficiently to be greater than the angle of repose of said fibers on said impeller (30) as said impeller (30) rotates.
Claim 4
Dependent Claim
61 words
The method according to claim 1 or 2, wherein said adhesion is decreased by reducing the coefficient of friction of said impeller (30) along a portion extending at least 10% of the length of each of the opposing surfaces thereof from said leading edge (38) to said trailing edge (40) below the coefficient of friction of the remainder of said surfaces.
Claim 5
Dependent Claim
189 words
Apparatus for circulating liquids having fibers suspended therein in a tank which comprises a draft tube (12) disposed in said tank (10), a shaft (28), an axial flow impeller (30) having a plurality of blades (32), said impeller (30) being disposed in said draft tube (12) on said shaft (28), said shaft (28) and said impeller (30) being coaxial with said tube (12), said blades (32) having opposite edges one of which leads the other as said impeller rotates, said leading edges (38), being inclined with respect to radial lines (60) from the axis (56) of said impeller (30) in planes perpendicular to said axis (56) at angles greater than the angle of repose of said fibers on said impeller (30) as said impeller (30) rotates through said liquids and said liquids flow in the direction axially of said impeller (30) through said draft tube (12) thereby preventing the accumulation of said fibers on said leading edge (38) and the increase of drag on said impeller (30) which prevents the rotation thereof at sufficient speed to circulate said liquids without increasing the power applied to rotate said shaft (28).
Claim 6
Dependent Claim
189 words
Apparatus for circulating liquids having fibers suspended therein in a tank which comprises a draft tube (12) disposed in said tank (10), a shaft (28), an axial flow impeller (30) having a plurality of blades (32), said impeller (30) being disposed in said draft tube (12) on said shaft (28), said shaft (28) and said impeller (30) being coaxial with said tube (12), said blades (32) having opposite edges one of which leads the other as said impeller rotates, said leading edges (38), being inclined with respect to radial lines (60) from the axis (56) of said impeller (30) in planes perpendicular to said axis (56) at angles greater than the angle of repose of said fibers on said impeller (30) as said impeller (30) rotates through said liquids and said liquids flow in the direction axially of said impeller (30) through said draft tube (12) thereby preventing the accumulation of said fibers on said leading edge (38) and the increase of drag on said impeller (30) which prevents the rotation thereof at sufficient speed to circulate said liquids without increasing the power applied to rotate said shaft (28).
Claim 7
Dependent Claim
54 words
The apparatus according to claim 4, wherein the angles between the one of said radial lines (60) which intersects said leading edges (38) where said one radial lines (60) are 70% of the radius from the axis (56) of said impeller (30) to the tips of said blades (32) are from 20° to 60°.
Claim 8
Dependent Claim
61 words
The apparatus according to claim 5, wherein said trailing edges (40) of said blades (32) define angles with radial lines from the axis (56) of said impeller in planes perpendicular thereto which intersects said trailing edges (40) which last named angles are smaller than said angles between said leading edges (38) and said radial lines which intersect said leading edges (38).
Claim 9
Dependent Claim
87 words
The apparatus according to claim 5, wherein in profile said blades have camber, said camber has a length from about 4% to 8% of the length of the chord of said blades (32) between said leading (38) and trailing (40) 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 (56) is greater adjacent to said hub than adjacent to said tips of said blades (32) and varies therebetween.
Claim 10
Independent Claim
48 words
The apparatus according to any one of claims 4 to 7, wherein said blades (32) have opposite surfaces portions of which extending from said leading edges (38) to said trailing edges (40) are of material (50) having lower coefficient of friction than the remainder of said blade surfaces.
Claim 11
Dependent Claim
24 words
The apparatus according to claim 8, wherein said portions are provided by inserts (50) which define said leading edges (38) and provide said surfaces.
Claim 12
Dependent Claim
14 words
The apparatus according to claim 9, wherein said material of said inserts is plastics.
References Cited (Backward Citations)
No citation records indexed.
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