EP0664155B1 - Stirrer - Google Patents

Description

The invention relates to a stirrer for stirring in particular low and medium viscosity liquids, with one attachment on an agitator shaft and an inner main blade and one with this connected outer side sheet. The main sheet of the Ruhrorgans is on the inside (at the end facing away from the side sheet) attached to an agitator shaft and the side sheet is attached outside.

Ruhr organs with stirring blades are known, their blade width is constant or tapers towards the tip of the leaf. From EP-A-0 577 456 a mixing element is known, the impeller of each a single leaf, which one is pointed outwards has tapered leaf shape. Propeller stirrers are also known Stirring blades with symmetrical, hanging or trailing Leaf shapes.

The disadvantage here is the high cost of materials and also difficult to manufacture. The axial speeds are also distributed more or less evenly in the discharge area. Other well-known agitators, according to the point of view Wing theory are made, a short circuit flow do not avoid and are therefore limited in their efficiency.

EP-A-0 542 713 describes a method and an apparatus for Mixing of fluids is known. According to the mixing procedure of fluids in a cylindrical mixing container a mixer is used, which has a first partial flow mainly in the longitudinal extent of the container as moving Column or a so-called central flow around the container axis around and creates a second partial flow that is opposite is directed, surrounding the columnar central flow and a so-called edge flow forms. In the device, the shape the mixing organs set such that their force effects on the fluid to form a columnar central flow and contribute to an annular edge flow. For this, a Shovel shape selected, with the blade area facing away from the agitator shaft in axial section an angle to that of the agitator shaft facing sheet area forms, and that of the agitator shaft facing leaf area at an angle to the plane of rotation of the Agitator is employed. The two leaf areas are from a uniform basic body with constant axial Width formed, for example, by appropriate folds. There will also be a near the bottom of the mixing tank arranged mixing element described, which a Shovel or a blade, the tip of which in one to Container axis is mainly inclined to the parallel plane To give fluid a radial-peripheral flow direction. The the mixing element facing the container bottom thus gives the fluid a preferred radially directed flow component in the mixing container.

In contrast, the invention is based on the object Mitigation of the difficulties outlined above Stirring device to provide a high hydraulic Efficiency.

According to the invention, this is a Ruhrorgan according to the claim 1 specified.

Funding is provided for the Ruhr organ according to the invention preferably in the axial direction, and there are short-circuit currents largely suppressed, which means that a widespread pressure Receives axial profile. This gives you a much higher one hydraulic efficiency thanks to a highly concentrated axial flow.

The angle δ ₀ is preferably in the range from approximately -25 ° to approximately + 25 ° and the angle of attack γ ₀ is preferably in the range from approximately 15 ° to approximately 29 °.

The main blade is advantageously bent along a radial line or a line running at an acute angle ε to it by an angle γ ₁ relative to the first section of the main blade, which is set at the angle of attack γ ₀ .

The bent section of the main sheet can expediently be followed by further sections, each of which is bent relative to the previous section by an angle γ ₂ or γ ₃ .

The angles γ ₁ , γ ₂ and γ ₃ are preferably in the range from approximately 7 ° to approximately 19 °.

According to a further embodiment, the main blade is at least partially curved in the tangential section, it being possible for further curved sections of different curvature to adjoin a flat section set at the angle of incidence γ ₀ to the plane of rotation.

The ratio of the radii of these bulges to the outside diameter the stirrer is preferably in the range of about 0.15 to about 0.8.

According to a further embodiment of the invention, the side sheet in the axial section simply or repeatedly kinked or arched. The bulge can have multiple sections Include different radii, the ratio of these Radii to the outside diameter of the stirrer preferably in Range is from about 0.1 to about 0.8.

The line connecting the main sheet and the side sheet can expediently form an angle of approximately 70 ° to approximately 95 ° form the radial centerline of the main blade, while the tangential centerline of the side sheet preferably about one Angles from 60 ° to 110 ° to the radial center line of the main blade can form.

Finally, the outer edge or outer contour is advantageous of the side sheet adapted to the circulating line of the stirring element or runs along this orbit.

Fig. 1

in schematischer Draufsicht ein Rührorgan nach der Erfindung zeigt.

Fig. 2a, 2b und 2c

zeigen im Schnitt längs der Linie A-A von Fig. 1 unterschiedliche Formen des Hauptblattes.

Fig. 3

zeigt in Draufsicht eine weitere Ausführungsform des erfindungsgemäßen Rührorganes.

Fig. 3a

zeigt einen Schnitt des Hauptblattes längs der Linie A-A von Fig. 3.

Fig. 4a, 4b und 4c

zeigen im axialen Schnitt längs der Linie B-B von Fig. 3 unterschiedliche Ausführungsformen des Seitenblattes.

Fig. 5 und 6

zeigen Varianten des erfindungsgemäßen Rührorganes nach Fig. 1.

For example, embodiments of the invention are described below with reference to the drawing, in which

Fig. 1

shows a schematic plan view of an agitator according to the invention.

2a, 2b and 2c

show in section along the line AA of Fig. 1 different shapes of the main sheet.

Fig. 3

shows a plan view of a further embodiment of the stirring element according to the invention.

Fig. 3a

shows a section of the main sheet along the line AA of Fig. 3rd

4a, 4b and 4c

show in axial section along the line BB of Fig. 3 different embodiments of the side sheet.

5 and 6

show variants of the stirring element according to the invention according to FIG. 1.

1 has, for example, a hub 12 as Attachment to a stirrer shaft, not shown, and a radial seen inner main sheet 14 and an outer side sheet 16. Das Main blade 14 can be welded directly to the hub 12 or without an additional fastener, for example in the form of a spar connected to the hub 18. The side leaf 16 is firmly connected to the main sheet 14, e.g. by welding, or both blades 14, 16 are formed in one piece, e.g. cast or formed from a flat piece of sheet metal. The thickness of the two stirring blades 14, 16 can be of the same design or that outer sheet 16 can be made with reduced sheet thickness.

The two stirring blades 14, 16 have a common front edge 20, which in the illustrated embodiment is parallel to one radial line R runs through the center of the as Attachment serving hub 12 goes.

A connecting line 22 between the main sheet 14 and the side sheet 16 extends at an angle β ₁ to this radial line R. The essentially tangential center line M of the side sheet 16 forms an angle β ₂ to the radial line R.

The angle β ₁ is in the range from approximately 70 ° to approximately 95 °, while the angle β _{2 is} in the range from approximately 60 ° to approximately 110 °.

The ratio of the tangential length l _{n of} the side blade 16 to the outer diameter d _{2 of} the stirring element 10 is in the range from about 0.15 to about 0.4.

The ratio of the diameter d _{6 of} the connecting line 22 between the main and side sheets 14 and 16 to the outer diameter d _{2 of} the stirring element 10 is in the range from about 0.25 to about 0.45.

1, the main blade 14 tapers radially from inside out, its corners pointed or can be rounded. The side sheet 16 is on the front and rounded rear corner, and particularly its outer edge or outer contour 60 is on the circumferential line of the stirring element 10 adapted or follows this orbit.

2a, 2b and 2c show different shapes of the main sheet 14 in a tangential section A-A of FIG. 1 or 3.

2a, the main sheet 16 consists of three sections 24, 26 and 28, according to FIG. 2b, from four sections 24, 26, 28 and 30.

The first section 24 is set at an angle γ _{0 to the} plane of rotation of the stirring element 10 of approximately 15 ° to approximately 29 °. Section 24 is followed by at least one further section 26, possibly further sections 28, 30. The section 26 is bent relative to the section 24 by an angle γ ₁ downward (away from the plane of rotation) along a line which runs parallel or at an acute angle (ε in FIG. 3) to the radial line R. Section 26 can be followed by a further section 28, which is bent relative to section 26 by an angle γ ₂ downward (away from the plane of rotation) along a line which is parallel (FIG. 1) or at an acute angle (ε in Fig. 3) to the radial R. In the embodiment according to FIG. 2b, section 28 is followed by a further corresponding section 30, which is bent downward at an angle γ ₃ relative to section 28.

The angles γ ₁ , γ ₂ and γ ₃ are in the range from approximately 7 ° to approximately 19 °.

The main sheet 14 thus comprises several sections 24 to 30, the increasingly stronger relative to the rotating plane of the agitator (Fig. 1) or are kinked at an acute angle (ε in FIG. 3), the kink lines being parallel to the radial line R.

The individual sections 24, 26, 28 and 30 are flat in themselves educated.

According to another embodiment, the main sheet 14 can Section A-A but also be arched with a uniform curvature or with curved sections with different radii or for example in the form of Combinations of curved and kinked sections.

2c shows an embodiment in which the first section 24 is flat and, as in FIGS. 2a and 2b, is set at the angle of rotation γ ₀ with respect to the plane of rotation of the stirring element 10. In the embodiment according to FIG. 2c, section 24 is adjoined by sections 32, 34, 36 which are curved one after the other with radii R1, R2 and R3, the individual sections tangentially into one another or with an angle γ ₁ in the range of approximately 7 ° pass to about 19 ° (Fig. 2a and 2b).

The variants of the main sheet shown in FIGS. 2a to 2c can also in the embodiment variants according to FIGS. 3 to 6 be provided.

The ratio of the radii R1, R2 and R3 to the outer diameter d _{2 of} the stirring element 10 is in the range from about 0.15 to about 0.8.

3 and 3a show an embodiment in which the lines 38, along which the main sheet 14 is kinked or arched, run at an acute angle ε to the radial line R. The Lines 38 advantageously run parallel to each other and the innermost line 38, which is closest to radial line R, preferably starts from the corner point 62 at which the trailing edge of the main sheet 14 and the side sheet 16 bump into each other.

The angle ε can range, for example, from about 5 ° to about 30 °, preferably from about 10 ° to about 23 °.

Fig. 3a shows a section of an arched leaf shape through the Main sheet 14 along line A-A of FIG. 3.

As in the embodiments according to FIGS. 2a, 2b and 2c, the main blade 14 can consist of a flat section 24, which is set at an angle γ ₀ to the plane of rotation of the stirring element 10. The section 24 can then, for example, be followed by further flat sections 26, 28, 30 at the angles γ ₁ , γ ₂ and γ ₃ or further curved sections with the radii R1, R2, R3 in accordance with the embodiment according to FIG. 2c.

4a, 4b and 4c show an axial section along the Line B-B of FIG. 3 or FIG. 1

As can be seen from FIG. 4a, the side sheet 16 is preferably bent upwards at an angle δ ₀ to the main sheet 14 (based on the stirred tank, not shown). The side sheet 16 can, however, also be bent downwards by the angle δ ₀ in the direction of the bottom of the stirred tank relative to the main sheet 14, as shown at 52.

The angle δ ₀ is preferably in the range from approximately -25 ° to + 25 °.

In the embodiment according to FIG. 4b, the side sheet 16 comprises three sections 40, 42 and 44 (with other sections can be provided).

Sections 40, 42 and 44 are flat in themselves and the inner section 40 forms with the main blade 14 the angle δ ₀ already mentioned. Section 40 is adjoined by section 42, which is bent relative to section 40 by an angle δ ₁ . The section 44 adjoining the section 42 to the outside is bent relative to the section 42 by an angle δ ₂ .

The fold lines between the sections 40 and 42 and between the sections 42 and 44 preferably run parallel to the center line M of the side sheet 16, which in turn, as already stated, includes the angle β ₂ with the radial line R (FIG. 1). The widths of the individual sections 40, 42 and 44 as well as the widths of the sections 24, 26, 28 and 30 can be designed differently. The kink angles δ ₁ , δ ₂ etc. between the individual sections 40, 42 and 44 are in the range from 0 to approximately 15 °. The sections 40, 42 and 44 are increasingly bent upwards, based on the stirred tank, not shown. However, as shown at 54, they can also be bent downwards towards the bottom of the stirred tank.

4c shows an embodiment in which the side sheet 16 is arched in axial section. The curvature can be even, but here is preferably the side sheet 16 of several sections with different curvature, i.e. different radii, with the main blade 14 connects first curved section 46 with a radius R1 which is followed by a second curved section 48 with the radius R2, and this in turn is followed by a third section 50 with the Radius R3. (Other sections may vary connect.)

The transition between the main sheet 14 and the first arched Section 46 as well as the transition between each arched Sections 46, 48, 50 takes place tangentially and so that the Page 16 continuously bulges upward, based on the stirred tank, not shown. But also in the embodiment 4c can be provided that the individual curved sections of the side sheet 16 down arch towards the bottom of the mixing bowl, as at 56 is shown.

The ratio of the radii R1, R2 and R3 to the outer diameter d _{2 of} the stirring element 10 is preferably in the range from about 0.1 to about 0.8.

For example, embodiments can also be provided for combinations of kinked and arched sections available. The variants shown in Figures 4a to 4c of the side sheet 16 can also in the embodiments shown further including Fig. 1 and in connection with 2a to 2c are provided.

Fig. 5 shows a variant of the stirring element according to Fig. 1, in which a slot 58 between the main sheet 14 and the side sheet 16 trained, i.e. the two stirring blades are only one Part of the tangential width of the main sheet 14 with each other connected.

Fig. 6 also shows a variant of the stirring element 10, at which the main blade 14 only on the spar 18 (but not directly on the hub 12) and the edges of the main blade 14 rounded and the transition between the main sheet 14 and the side sheet 16 is rounded.

A broken line is alternatively a square one in FIG. 6 Design variant of an outer contour of a stirrer with Main sheet and side sheet shown as an example. Same or Similar variants can also be used for the others Embodiments of the stirring elements shown as well as combinations partially rounded and partially angular.

The stirrer according to the invention can have multiple blades, in particular be double-winged. The ratio of the outside diameter of the agitator to the inside diameter of the agitator at about 0.2 to about 0.7. Funding is preferably given in axial direction, with the agitator according to the invention Short-circuit currents are largely suppressed, which is the pressure side results in a broadened axial profile, and by a expresses significantly increased efficiency. The agitator will preferred for low-viscosity and medium-viscosity single or multi-phase liquids used in round or rectangular Containers that have a diameter of about 0.5 m to about 20 m and more can have. If necessary, can also on a stirrer shaft several stirring elements can be arranged one above the other.

The rotary movement of the stirrer according to the invention can in the agitated liquid is a highly concentrated axial jet are preferably generated in the direction of the container bottom, which means that the contents of the container are thoroughly mixed is guaranteed.

The stirring element according to the invention can be made of any metallic Materials or plastic exist. It can be surface treated be, e.g. sandblasted, polished, clothed, coated, rubberized or enamelled. It can be with or without baffles can be used in the stirred tank and it can be centric, eccentric or be installed at an angle in the stirred tank.

In summary, the invention provides a stirring element for stirring e.g. low-viscosity and medium-viscosity liquids. The Stirrer comprises an inner main blade and an outer side blade, which are both connected. The main sheet is preferably bent down with respect to the agitator plane or arched while the side sheet preferably in relation to the level of the agitator is kinked or curved. Through this training of the agitator is achieved a high hydraulic efficiency and thus a very good mixing of the mix lowest energy inputs possible.

Claims (19)

1. Stirring element for stirring in particular low viscosity and medium viscosity liquids, having a mounting on a stirrer shaft (12) as well as an inner main blade (14) and an external side blade (16) connected to the latter, which also has the following features:

   a) the side blade (16) forms an angle (δ₀) with the main blade (14) in axial section,

   b) the main blade (14) is set at an angle (γ₀) to the plane of rotation of the stirring element (10), and

   c) for preferred axial conveying, the tangential length (1_n) of the side blade (16) is greater than the width of the main blade (14) at the transition point from the main to the side blade,

   d) the ratio of the tangential length (l_n) of the side blade (16) to the external diameter (d₂) of the stirring element (10) lies in the range from about 0.15 to about 0.4, and

   e) the main blade (14) and the side blade (16) form a common leading edge (20).
2. Stirring element according to claim 1, characterised in that the setting angle (γ₀) lies in the range from about 15° to about 29°.
3. Stirring element according to claim 1 or 2, characterised in that the angle (δ₀) lies in the range from about -25° to about +25°.
4. Stirring element according to one of claims 1 to 3, characterised in that the main blade (14) is bent along a line (38), which runs parallel or at an acute angle (ε) to a radial line (R) of the main blade (14), by an angle (γ₁) relative to a first section (24) of the main blade (14), which forms the setting angle (γ₀) with the plane of rotation of the stirring element.
5. Stirring element according to claim 4, characterised in that further sections (28, 30) follow the bent section (26) of the main blade (14) and are bent in each case relative to the preceding section by the angle (γ₂ or γ₃) along the parallel bending lines (38) at a distance from one another.
6. Stirring element according to claim 4 or 5, characterised in that the angles (γ₁, γ₂ and γ₃) lie in the range from about 7° to about 19°.
7. Stirring element according to one of claims 1 to 6, characterised in that the main blade (14) is designed to be at least partially arched in tangential section.
8. Stirring element according to one of the preceding claims, characterised in that at least one, preferably several arched sections (32, 34, 36) having radii (R1, R2 and R3) follow a flat section (24) set at the setting angle (γ₀) to the plane of rotation.
9. Stirring element according to claim 8, characterised in that the ratio of the radii (R1, R2 and R3) to the external diameter (d₂) of the stirring element (10) lies in the range from about 0.15 to about 0.8.
10. Stirring element according to claim 1, characterised in that at least one, preferably several further sections (42, 44) follow a first section (40) of the side blade (16) which forms the angle (δ₀) with the main blade (14), which sections (42, 44) are bent in each case relative to the preceding section by angles (δ₁ or δ₂) along parallel lines spaced apart in the radial direction which run preferably parallel to the central line (M) of the side blade (16) which forms an angle (β₂) with a radial line (R) of the main blade (14).
11. Stirring element according to claim 10, characterised in that the angles (δ₁ and δ₂) lie in the range from about 0 to about 15°.
12. Stirring element according to claim 10 or 11, characterised in that the angle (β₂) lies in the range from about 60° to about 110°.
13. Stirring element according to one of the preceding claims, characterised in that the side blade (16) is designed to be at least partially arched in axial section.
14. Stirring element according to claim 13, characterised in that the side blade (16) is formed from several sections (46, 48, 50) of different curvature having radii (R1, R2 and R3).
15. Stirring element according to claim 14, characterised in that the ratio of the radii (R1, R2 and R3) to the external diameter (d₂) of the stirring element lies in the range from about 0.1 to 0.8.
16. Stirring element according to one of the preceding claims, characterised in that the connecting line (22) between main blade (14) and side blade (16) runs at an angle (β₁) in the range of about 70° to about 95° with a radial line (R) of the main blade (14).
17. Stirring element according to one of the preceding claims, characterised in that the external edge (60) of the side blade (16) is matched to the peripheral line of the stirring element (10).
18. Stirring element according to one of the preceding claims, characterised in that the ratio of diameter (d₆) of the main blade (14) to the external diameter (d₂) of the stirring element (10) lies in the range from about 0.25 to about 0.45.
19. Stirring element according to one of the preceding claims, characterised in that the ratio of external diameter (d₂) of the stirring element (10) to the internal diameter of the stirring container lies in the range from about 0.02 to 0.7.

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