METHOD AND STIRRING ELEMENT DEVICE FOR MIXING MEDIUM VISCOUS TO HIGH VISCOUS FLUIDS AND/OR PASTES

Abstract

A method in which a medium viscous to highly viscous fluid and/or a medium viscous to highly viscous suspension are/is mixed by means of an agitator device that is driven by a drive shaft, wherein

the fluid and/or the suspension are/is brought into a multi-dimensional flow by means of a close-clearance stirring blade (14) of the agitator device, and a flow resistance is minimized along a shaft direction in a shaft proximity.

Claims

1. A method in which a medium viscous to highly viscous fluid and/or a medium viscous to highly viscous suspension are/is mixed by means of an agitator device (10) that is driven by a drive shaft, wherein the fluid and/or the suspension are/is brought into a multi-dimensional flow by means of a close-clearance stirring blade of the agitator device, and a flow resistance is minimized along a shaft direction in a shaft proximity that extends over a region of an imaginary cylinder, whose main extension runs substantially parallel to a main extension of the drive shaft and whose radius corresponds to at least 10% of a radius of a stirring container.

2. The method according to claim 1, wherein the multi-dimensional flow of the fluid and/or the suspension is created at least partly by means of at least one further close-clearance stirring blade of the agitator device, which is offset along the drive shaft.

3. The method according to claim 2, wherein with respect to a circumferential direction of the drive shaft, the further close-clearance stirring blade is driven at an angular offset to the close-clearance stirring blade.

4. The method according to claim 3, wherein in a view direction along the drive shaft, a plurality of at least four close-clearance stirring blades are driven simultaneously, the close-clearance stirring blades being driven, in a circumferential direction of the drive shaft, respectively offset from one another by an angle that corresponds to a quotient of 360° and a number of stirring blades.

5. The method according to claim 1, wherein the stirring blade is driven at an acute pitch angle relative to a plane that is perpendicular to the drive shaft.

6. The method according to claim 1, wherein the multi-dimensional flow of the fluid and/or the suspension is created at least partly by means of at least one close-clearance counter-stirring blade which, viewed along the drive shaft, is situated opposite the close-clearance stirring blade and is arranged at a same level.

7. The method according to claim 1, wherein a drive momentum is transferred from the drive shaft to the stirring blade by means of a connection element of the agitator device, whose, in particular essentially oval, preferably circle-shaped cross section minimizes the flow resistance along the shaft direction in the shaft proximity.

8. The method according to claim 7, wherein due to the minimized flow resistance, the connection element is driven with a percentage of the drive momentum transferred from the drive shaft to the close-clearance stirring blade that is smaller than 10%.

9. The method according to claim 1, wherein a layer of the fluid and/or the suspension that is close to a bottom is brought into a flow by means of a bottom stirring blade of the agitator device.

10. An agitator device which is configured for a mixing of a medium viscous to highly viscous fluid and/or a medium viscous to highly viscous suspension, in particular for an execution of the method according to claim 1, comprising at least one close-clearance stirring blade, a drive shaft, and a connection element which connects the stirring blade to the drive shaft, wherein the connection element has an outer contour that is configured to minimize a flow resistance of a multi-dimensional flow of the fluid and/or the suspension, which is generated by the stirring blade in an operative state, along a shaft direction in a shaft proximity that extends over a region of an imaginary cylinder, whose main extension runs substantially parallel to a main extension of the drive shaft and whose radius corresponds to at least 10% of a radius of a stirring container.

11. The agitator device according to claim 10, wherein the connection element has an at least essentially oval, preferably circle-shaped cross section.

12. A stirring system with a stirring container and with an agitator device according to claim 10, in particular for an execution of a method according to claim 1, wherein the close-clearance stirring blade is arranged within the stirring container at least partly such that it is movable in a proximity of an inner wall of the stirring container, wherein a maximum distance of the proximity to the inner wall corresponds to maximally 10% of a diameter of the stirring container.

Description

DRAWINGS

[0026] Further advantages will become apparent from the following description of the drawings. In the drawings an exemplary embodiment of the invention is illustrated. The drawings, the description and the claims contain a plurality of features in combination. Someone skilled in the art will purposefully consider the features separately and will find further expedient combinations.

[0027] It is shown in:

[0028] FIG. 1 a stirring system with a stirring container and with an agitator device arranged in the stirring container,

[0029] FIG. 2 the agitator device in a view direction along a drive shaft of the agitator device,

[0030] FIG. 3 a close-clearance stirring blade of the agitator device, and

[0031] FIG. 4 a schematic flow chart concerning a method in which a medium viscous to highly viscous fluid and/or a medium viscous to highly viscous fluid are/is mixed by means of an agitator device.

DESCRIPTION OF THE EXEMPLARY EMBODIMENT

[0032] FIG. 1 shows a stirring system 40. The stirring system 40 comprises a stirring container 42 and an agitator device 10. The stirring system 40 comprises a drive unit 52. The drive unit 52 is configured to provide a drive momentum and to transfer said drive momentum to a drive shaft 12 of the agitator device 10.

[0033] The agitator device 10 is configured for mixing a medium viscous to highly viscous fluid and/or a medium viscous to highly viscous suspension. The agitator device 10 comprises the drive shaft 12 and a close-clearance stirring blade 14. The agitator device 40 comprises a connection element 34, which connects the close-clearance stirring blade 14 to the drive shaft 12. The close-clearance stirring blade 14 is arranged in the stirring container 42 at least partly in such a way that it is movable in a proximity 44 of an inner wall 46 of the stirring container 42. In an operative state of the agitator device 10 the close-clearance stirring blade 14 is movable around the drive shaft 12 in a circumferential direction 22.

[0034] The connection element 34 has an outer contour 38. The outer contour 38 is configured to minimize a flow resistance of a multi-dimensional flow (not shown), generated by the stirring blade 14 in an operative state, of the fluid and/or the suspension along a shaft direction 16 in a shaft proximity 18. The connection element 34 has an at least essentially oval cross section 56. In the present case the cross section of the connection element 34 is essentially circle-shaped.

[0035] The agitator device 10 comprises a further close-clearance stirring blade 20. The further close-clearance stirring blade 20 is arranged along the drive shaft 12 offset to the close-clearance stirring blade 14. The agitator device 10 comprises a further connection element 48 connecting the further close-clearance stirring blade 20 to the drive shaft 12. In the operative state of the agitator device 10, the further close-clearance stirring blade 20 is drivable at an angular offset to the close-clearance stirring blade 13 with respect to a circumferential direction 22 of the drive shaft 12.

[0036] The agitator device 10 comprises a close-clearance counter-stirring blade 24. Viewed along the drive shaft 12, the close-clearance counter-stirring blade 24 is arranged at the same level as and opposite to the close-clearance stirring blade 14. The close-clearance counter-stirring blade 24 is connected to the drive shaft 12 via a further connection element 50 of the agitator device 10.

[0037] The agitator device 10 comprises a further close-clearance counter-stirring blade 26. Viewed along the drive shaft 12, the further close-clearance counter-stirring blade 26 is arranged at the same level as and opposite to the further close-clearance stirring blade 20. The further close-clearance counter-stirring blade 26 is connected to the drive shaft 12 via a further connection element 54 of the agitator device 10.

[0038] The close-clearance stirring blade 14, the further close-clearance stirring blade 20, the close-clearance counter-stirring blade 24 and the further close-clearance counter-stirring blade 26 have geometries that are substantially identical to one another and dimensions that are substantially identical.

[0039] The further connection elements 48, 50, 54 each have a geometry and a dimension that is substantially identical to the connection element 34, and they are also configured to minimize a flow resistance of the fluid and/or the suspension along the shaft direction 16 in a shaft proximity 18.

[0040] The agitator device 10 comprises a bottom stirring blade 36. The bottom stirring blade 36 is connected to the drive shaft 12 and is configured to bring a layer of the fluid and/or the suspension that is close to the bottom into a flow.

[0041] FIG. 2 shows a schematic view of the agitator device 10 in a view direction along the drive shaft 12. The agitator device 10 comprises a plurality of close-clearance stirring blades 14, 20, 24, 26 which are arranged, in a circumferential direction 22 of the drive shaft 12, respectively offset to one another by an angle 28. The angle 28 is equivalent to a quotient of 360° and a number of stirring blades. In the present exemplary embodiment the agitator device 10 comprises a number of precisely four close-clearance stirring blades, namely the close-clearance stirring blade 14, the further close-clearance stirring blade 20, the close-clearance counter-stirring blade 24 and the further close-clearance counter-stirring blade 26, such that the angle 28 is here equivalent to an angle of 90°.

[0042] FIG. 3 shows a schematic partial view of the agitator device 10 with a view direction onto the close-clearance stirring blade 14 along a plane 32 that is perpendicular to the drive shaft 12. The stirring blade 14 is arranged at an acute pitch angle 30 relative to the plane 32 that is perpendicular to the drive shaft 12. In the present exemplary embodiment the acute pitch angle 30 is equivalent to an angle of 45°. The close-clearance counter-stirring blade 24 is arranged at a further acute pitch angle 64 relative to the plane 32 that is perpendicular to the drive shaft 12. The further acute pitch angle 64 is identical to the acute pitch angle 30 and in the present case also has an absolute value of 45°.

[0043] FIG. 4 shows a schematic flow chart of a method in which a medium viscous to highly viscous fluid and/or a medium viscous to highly viscous suspension are/is mixed by means of the agitator device 10 that is driven by the drive shaft 12. In a first method step 58 the stirring container 42 is filled with the medium viscous to highly viscous fluid and/or the medium viscous to highly viscous suspension. In a further method step 60 the agitator device 10 is arranged in the stirring container 42. In a further method step 62 the agitator device 10 is set into operation. A drive momentum provided by the drive unit 52 is transferred to the drive shaft 12 and, for the purpose of driving the agitator device 10, brings the drive shaft 12 into a rotary movement in the circumferential direction 22. The drive momentum is transferred from the drive shaft 12 to the close-clearance stirring blade 14 by means of the connection element 34 of the agitator device 10, bringing the stirring blade 14 into a rotary movement in the circumferential direction 22. The stirring blade 14 is driven at the acute pitch angle 30 relative to the plane 32 that is perpendicular to the drive shaft 12. The fluid and/or the suspension is herewith brought into a multi-dimensional flow. A flow resistance of the multi-dimensional flow is herein minimized along the shaft direction 16 in the shaft proximity 18. The flow resistance along the shaft direction 16 in the shaft proximity 18 is herein minimized due to the circle-shaped cross section 56 of the connection element 34. As a result of the minimized flow resistance, the connection element 34 is driven with a percentage of the drive momentum transferred from the drive shaft to the close-clearance stirring blade 14 that is smaller than 5%. The multi-dimensional flow of the fluid and/or the suspension is created at least partly by the close-clearance counter-stirring blade 24 that is, viewed along the drive shaft, opposite the close-clearance stirring blade 14 and is arranged at a same level. The multi-dimensional flow of the fluid and/or the suspension is moreover created at least partly by means of the further close-clearance stirring blade 20 of the agitator device 10, which is arranged offset along the drive shaft 12. With respect to a circumferential direction 22 of the drive shaft 12, the further close-clearance stirring blade 20 is driven at an angular offset to the close-clearance stirring blade 14. In a view direction along the drive shaft 12, the four close-clearance stirring blades 14, 20, 24, 26 are driven simultaneously, wherein the close-clearance stirring blades 14, 20, 24, 26 are driven, in the circumferential direction 22 of the drive shaft 12, respectively offset from one another by the angle 28. The layer of the fluid and/or the suspension that is close to the bottom is brought into a flow by means of the bottom stirring blade 36 of the agitator device 10. In a further method step 62, following sufficient mixing of the medium viscous to highly viscous fluid and/or the medium viscous to highly viscous suspension, the agitator device 10 is switched off and is removed from the stirring container 42. The mixed medium viscous to highly viscous fluid and/or the mixed medium viscous to highly viscous suspension may then be taken from the stirring container 42 and, for example, may be fed to a further processing procedure or may be packaged as an end product. The method may be designed as a batch process, with discontinuous execution of the method steps 58, 60, 62. It is however also conceivable that the further method step 60 is carried out continuously, with a sub-quantity of a mixed fluid and/or mixed suspension being conveyed out of the stirring container 42 and a quantity of fluid and/or suspension that is to be mixed being continuously fed to the stirring container 42.

REFERENCE NUMERALS

[0044] 10 agitator device

[0045] 12 drive shaft

[0046] 14 close-clearance stirring blade

[0047] 16 shaft direction

[0048] 18 shaft proximity

[0049] 20 further close-clearance stirring blade

[0050] 22 circumferential direction

[0051] 24 close-clearance counter-stirring blade

[0052] 26 further close-clearance counter-stirring blade

[0053] 28 angle

[0054] 30 acute pitch angle

[0055] 32 perpendicular plane

[0056] 34 connection element

[0057] 36 bottom stirring blade

[0058] 38 outer contour

[0059] 40 stirring system

[0060] 42 stirring container

[0061] 44 proximity

[0062] 46 inner wall

[0063] 48 further connection element

[0064] 50 further connection element

[0065] 52 drive unit

[0066] 54 further connection element

[0067] 56 cross section

[0068] 58 first method step

[0069] 60 further method step

[0070] 62 further method step

[0071] 64 further acute pitch angle