Process and stirring device for mixing medium-viscosity to high-viscosity fluids and/or pastes

State of the art

The invention relates to a method in which a medium-viscosity to high-viscosity fluid and/or a medium-to-high-viscosity suspension is mixed by means of a stirring element device which is driven via a drive shaft, according to the preamble of claim 1, and a stirring element device according to Preamble of claim 10.

A large number of methods or stirring element devices for mixing medium-viscosity to high-viscosity fluids and/or suspensions are already known from the prior art. For example, in DE 25 57 979 C2, a stirring device with two outer stirring elements is used, which are connected to a drive shaft, with an inner stirring element being arranged between the outer stirring elements and the drive shaft, which is intended to create an upward or downward flow to generate in the axial direction of the drive shaft. The inner stirring elements are arranged at an angle of attack obliquely to a plane of rotation. Similar arrangements of stirring elements are also known, for example, from the documents CH 593 711 A4, CN 204 768 523 U, DE 603 17 772 T2, DE 10 2007 054 428 A1, EP 0 063 171 A2 or JP 44 32 438 B2, with one Geometry and / or an angle of the inner stirring elements was changed and developed in a variety of ways. However, all of the above publications have in common that a flow in the axial direction is to be generated or increased by means of internal stirring elements, which inevitably involves increased flow resistance in the vicinity of the drive shaft and thus an increased power requirement for torque generation.

The object of the invention is, in particular, to provide a generic method and a generic stirring element device with improved properties in terms of efficiency. The object is achieved according to the invention by the features of claims 1 and 10, while the subclaims can be found in front of some refinements and developments of the invention.

Advantages of the Invention

The invention is based on a method in which a medium-viscosity to high-viscosity fluid and/or a medium-viscosity to high-viscosity suspension, in particular a medium-viscosity to high-viscosity paste, is mixed by means of a stirring organ device which is driven via a drive shaft.

It is proposed that the fluid and/or the suspension be caused to flow multidimensionally by means of a stirring blade of the stirring element device that moves along the wall, and that a flow resistance along a wave direction in a region close to the wave is minimized.

Such a configuration can advantageously provide a particularly efficient method for mixing medium-viscosity to high-viscosity fluids and/or suspensions. In particular, a particularly energy-efficient method can advantageously be provided by minimizing the flow resistance along the direction of the waves in the region close to the waves, reducing the electrical power required to drive the stirring element device while at least maintaining the, in particular improved, mixing rate. Due to the increased energy efficiency, a high cost saving can be achieved in a particularly advantageous manner, in particular when highly viscous fluids and/or suspensions are mixed, which occur, for example, in the production of plastics. Experimental investigations of

melderin also delivered results which, in view of the state of the art, can be regarded as completely surprising: Contrary to previous assumptions, it could be shown that, in addition to the aforementioned energetic advantages, there is also a particularly advantageous Mixing rate of the fluid and / or the suspension can be significantly improved in the axial direction. In this respect, the present invention represents a complete departure from the approach of previous methods or the design of previous stirring element devices for mixing medium-viscosity to high-viscosity fluids and/or suspensions.

The method and/or the agitator device is suitable for mixing medium-viscosity to high-viscosity fluids and/or suspensions with a dynamic viscosity of preferably at least 500 mPa s, in particular at least 1,000 mPa s, advantageously at least 10,000 mPa s, particularly advantageous at least 20,000 mPa s, preferably at least 40,000 mPa s and particularly preferably at least 50,000 mPa s.

The drive shaft of the stirring element device is equipped with a drive unit, which, for example, is an electric motorr to generate a drive torque, a clutch and / or gear element to transmit the drive torque element and other elements can include, connectable. The drive unit can be part of the stirring element device. The drive shaft of the stirring organ device can preferably be connected to a large number of different external drive units.

The agitator blade that travels along the wall has at least one outer partial area which, in an operating state of the agitator element device, can be moved, by means of a drive torque provided via the drive shaft, on a path of movement in the vicinity of an inner wall, in particular a side wall, of a stirred tank in which the fluid to be mixed and / or the suspension to be mixed is arranged to be movable. A maximum distance of the partial area of the wall-moving stirring blade to the inner wall, in particular

to the side wall of the stirred tank preferably corresponds to at most 10%, preferably at most 8% and particularly preferably at most 5% of the diameter of the stirred tank. The movement path of the partial area of the wall-moving agitator blade is in particular at least essentially parallel to the wall, in particular to the side wall, of the agitated container and runs in particular in a region close to the wall, in particular the side wall, of the agitated container.

The multidimensional flow has at least two flow components, which are oriented in spatial directions that differ from one another. The multidimensional flow has at least one axial flow component, which is oriented at least essentially parallel to a main extension of the drive shaft. In addition to the axial flow component, the multidimensional flow can have at least one radial flow component, which is at least essentially perpendicular to the axial flow component, and/or at least one tangential flow component, which is at least essentially perpendicular to both the axial and the radial flow component is oriented, have. The flow components are preferably oriented to one another at an at least substantially perpendicular angle, which preferably deviates from an angle of 90° by an amount of less than 8°, preferably less than 5° and particularly preferably less than 2°. The direction of the shaft is preferably oriented at least essentially parallel to a main extension of the drive shaft and preferably deviates from a direction of the main extension by an angle of no more than 8°, preferably by no more than 5° and particularly preferably by no more than 2°. A “main extent” of an object is to be understood as meaning the longest edge of a smallest geometric cuboid that just about completely encloses the object. The area near the shaft preferably extends over an area of an imaginary cylinder, the main extension of which runs essentially parallel to the main extension of the drive shaft and the radius of which is at least 10%, advantageously at least 20%, preferably at least 30% and particularly preferably at least 40% of a radius of the Mixing container corresponds.

It is also proposed that the multi-dimensional flow of the fluid and/or the suspension be generated at least partially by means of at least one additional stirring blade of the stirring element device that moves along the wall and is offset along the drive shaft. A particularly uniform thorough mixing of the medium-viscosity to high-viscosity fluid and/or the medium-viscosity to high-viscosity suspension can advantageously be achieved by means of flow. For applications with large volumes of medium-viscosity to high-viscosity fluids to be mixed and/or medium-viscosity to high-viscosity suspensions, it is conceivable that a multi-dimensional flow is generated by means of a large number of stirring blades of the stirring element device that can move along the wall, which are arranged offset to one another along the drive shaft .

In addition, it is proposed that the additional agitator blade that runs along the wall is driven at an angle offset to the agitator blade that runs along the wall, based on a circumferential direction of the drive shaft. In this way, a particularly uniform thorough mixing of the medium-viscosity to high-viscosity fluid and/or the medium-viscosity to high-viscosity suspension can advantageously be achieved. In addition, the stability of the drive shaft can advantageously be increased.

It is also proposed that a plurality of at least four wall-moving agitator blades be driven simultaneously in the direction of view along the drive shaft, with the agitator blades being driven offset in relation to one another in the circumferential direction of the drive shaft by an angle corresponding to a quotient of 360° and a number of the agitator blades . In the case of exactly four wall-moving stirring blades, which are started at the same timebecome flat, these are respectively offset from one another in the circumferential direction of the drive shaft. As a result, a particularly uniform mixing of the medium-viscosity to high-viscosity fluid and/or the medium-viscosity to high-viscosity suspension can advantageously be achieved in the circumferential direction of the drive shaft.

It is also proposed that the stirring blade is driven at an acute angle of attack relative to a plane perpendicular to the drive shaft. Such a configuration can advantageously further improve the mixing of the medium-viscosity to high-viscosity fluid and/or the medium-to-high-viscosity suspension in the circumferential direction of the drive shaft. The acute angle of attack can be an angle of at most 80°, in particular at most 70°, particularly advantageously at most 60° and particularly preferably between 40° and 50°. The agitator blade is preferably moved at an acute angle of attack of at least substantially 45° to the plane perpendicular to the drive shaft.

In addition, it is proposed that the multi-dimensional flow of the fluid and/or the suspension be generated at least partially by means of at least one counter-agitator blade arranged on the same surface as viewed along the drive shaft and opposite the agitator blade that moves on the wall. Through this, mixing of the fluid and/or the suspension in the radial and/or tangential direction of flow can advantageously be improved and a particularly uniform and stable drive can be achieved by the drive shaft. In an advantageous embodiment, the wall-moving counter-agitator blade is driven at a further acute angle of attack relative to the plane perpendicular to the drive shaft. An amount of the additional acute angle of attack preferably corresponds essentially to the amount of the acute angle of attack of the wall-moving stirring blade relative to the plane perpendicular to the drive shaft. Preferably, the agitator blade running along the wall and the counter-stirring blade running along the wall have a geometry that is essentially identical to one another and dimensions that are essentially identical to one another. Preferably, the wall-moving stirring blade and the further wall-moving stirring blade can be transferred into one another by rotating the drive shaft through 180° in the circumferential direction.

In addition, it is proposed that a drive torque is transmitted from the drive shaft to the stirring blade by means of a connecting element of the stirring element device, the cross section of which, in particular being essentially oval, preferably circular, minimizes the flow resistance along the direction of the shaft in the region near the shaft. By using a connecting element whose outer contour minimizes the flow resistance along the direction of the wave in the vicinity of the wave due to its oval, in particular circular cross-section, a particularly energy-efficient method for mixing medium-viscosity to high-viscosity fluids and/or suspensions can advantageously be provided. At the same time, a reliable transmission of the drive torque from the drive shaft to the at least one agitator blade that can move along the wall can be achieved.

It is also proposed that the connecting element, due to the minimized flow resistance, is moved with a share of less than 10%, preferably less than 5%, of the drive torque transmitted from the drive shaft to the agitator blade that travels along the wall. Fliering can provide a particularly efficient method for mixing medium-viscosity to high-viscosity fluids and/or suspensions. In particular for mixing highly viscous fluids and/or suspensions with a dynamic viscosity of 50,000 mPa s or more, the energy expenditure for generating a drive torque required for mixing can be particularly advantageously reduced and thus significant cost savings can be achieved.

In addition, it is proposed that a layer of the fluid and/or the suspension close to the bottom is caused to flow by means of a bottom stirring blade of the stirring element device. As a result, particularly uniform mixing can also be achieved in the layer of the fluid and/or the suspension close to the bottom. In addition, a sedimentation of particles to be suspended in the fluid and/or suspended in the suspension, which is undesirable in many applications, can advantageously be counteracted. The layer of the fluid and/or the suspension close to the bottom preferably comprises a subset of the fluid and/or the suspension which, starting from a mixing tank bottom of a mixing tank, takes up at least 15% of a total volume capacity of the mixing tank.

The invention is also based on an agitator device which is used for mixing a medium-viscosity to high-viscosity fluid and/or a medium-viscosity to high-viscosity suspensionis provided, comprising at least one agitator blade that travels along the wall, a drive shaft and a connecting element which connects the agitator blade to the drive shaft.

It is proposed that the connecting element has an outer contour which is intended to minimize flow resistance of a multidimensional flow of the fluid and/or the suspension generated by the stirring blade in an operating state along a wave direction and in a wave vicinity. In this way, a stirring element device with a particularly high energy efficiency can advantageously be provided. The connecting element could be connected to the drive shaft in a materially bonded manner, for example by means of a welded and/or soldered and/or adhesive connection. The connecting element is preferably connected to the drive shaft via a positive and/or non-positive connection, in particular via a shaft-hub connection. The wall-moving stirring blade could be formed in one piece with the connecting element. “In one piece” is to be understood as meaning at least materially connected, such as by a welding process and/or adhesive process, etc., and particularly advantageously molded, such as by the opening from a single cast and/or by the opening in a one-component or multi-component injection molding process . Preferably, the agitator blade that travels along the wall is connected to the connecting element in a positive and/or non-positive manner, for example via a plug-in connection, a screw connection or the like.

“Provided” should be understood to mean specially designed and/or equipped. The fact that an object is provided for a specific function should be understood to mean that the object fulfills and/or executes this specific function in at least one application and/or operating state.

Furthermore, it is proposed that the connecting element has an at least essentially oval, preferably circular, cross section. Due to this, the flow resistance along the wave direction in the area close to the wave can advantageously be minimized with particularly simple technical means. At the same time, a reliable transmission of a drive torque from the drive shaft to the at least one agitator blade that travels along the wall can advantageously be achieved. The connecting element could have at least one cross-sectional change along its main extension, such as a cross-section taper and/or a change in the shape of the cross-section, for example a transition from an oval cross-section to a circular cross-section or the like. A shape and a surface area of the cross section of the connecting element are preferably at least essentially constant along the main extent of the connecting element. As a result, a manufacturing process can advantageously be simplified and a cost saving can thus be achieved.

In addition, a stirring system with a stirred container and with a stirring device is proposed, the wall-moving stirring blade being arranged within the stirred container so that it can move at least partially in the vicinity of an inner wall of the stirred container. As a result, a particularly efficient and reliable stirring system with advantageous flow properties can advantageously be provided.

The method according to the invention and the stirring element device according to the invention should not be limited to the application and embodiment described above. In particular, the method according to the invention and the stirring element device according to the invention can have a number of individual elements, components and units as well as method steps that differs from the number specified here in order to fulfill a function described herein.

drawings

Further advantages result from the following description of the drawing. In the drawings an embodiment of the invention is shown. The drawings, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into further meaningful combinations.

Show it:

1 shows a stirring system with a stirring vessel and a stirring element device arranged in the stirring vessel,

2 shows the stirring element device in the direction of view along a drive shaft of the stirring element device,

3 shows a stirring blade that runs along the wall of the stirring element device and FIG.

Description of the embodiment

1 shows a stirring system 40. The stirring system 40 comprises a stirring vessel 42 and a stirring element device 10. The stirring system 40 comprises a drive unit 52. The drive unit 52 is intended to be a drivebsmoment be ready and carry on to a drive shaft 12 of the agitation device 10 to transfer.

WE CLAIM:

AMENDED CLAIMS

received by the International Bureau on 30 August 2021 (08/30/2021)

1. Method in which a medium-viscosity to high-viscosity fluid and/or a medium-viscosity to high-viscosity suspension is mixed by means of a stirring element device (10) which is driven via a drive shaft (12), characterized in that the fluid and/or the Suspension is put into a multi-dimensional flow by means of a stirring blade (14) that moves along the wall of the stirring element device (10) and a flow resistance along a wave direction (16) in a near-wave area (18), which extends over an area of an imaginary cylinder, whose Flaupter extension runs essentially parallel to a flap extension of the drive shaft (12) and whose radius corresponds to at least 10% of a radius of a stirred tank (42), is minimized.

2. The method according to claim 1, characterized in that the multi-dimensional flow of the fluid and/or the suspension is generated at least partially by means of at least one additional wall-moving stirring blade (20) of the stirring element device (10) that is offset along the drive shaft (12). .

3. The method according to claim 2, characterized in that the further agitator blade (20) running along the wall is driven at an angle offset to the agitating blade (14) running along the wall relative to a circumferential direction (22) of the drive shaft (12).

AMENDED SHEET (ARTICLE 19)

4. The method according to claim 3, characterized in that in the viewing direction along the drive shaft (12) a plurality of at least four wall-moving stirring blades (14, 20, 24, 26) are driven simultaneously, the wall-moving stirring blades (14, 20, 24, 26) in the circumferential direction (22) of the drive shaft (12) offset by an angle (28) corresponding to a quotient of 360° and a number of stirring blades (14, 20, 24, 26).

5. The method according to any one of the preceding claims, characterized in that the stirring blade (14) is driven at an acute angle (30) relative to a plane (32) perpendicular to the drive shaft (12).

6. The method according to any one of the preceding claims, characterized in that the multi-dimensional flow of the fluid and/or the suspension is at least partially achieved by means of at least one counter-agitator blade ( 24) is generated.

7. The method according to any one of the preceding claims, characterized in that a drive torque is transmitted from the drive shaft (12) to the stirring blade (14) by means of a connecting element (34) of the stirring element (10), which is essentially more oval , preferably circular, cross-section (56) minimizes the flow resistance along the wave direction (16) in the near-wave area (18).

AMENDED SHEET (ARTICLE 19)

8. The method according to claim 7, characterized in that the connecting element (34), due to the minimized flow resistance, is driven with a proportion of less than 10% of the drive torque transmitted from the drive shaft to the agitator blade (14) that travels along the wall.

9. The method according to any one of the preceding claims, characterized in that a layer of the fluid and/or the suspension close to the bottom is caused to flow by means of a bottom stirring blade (36) of the stirring element device (10).

10. Agitating element device (10), which is provided for mixing a medium-viscosity to high-viscosity fluid and/or a medium-viscosity to high-viscosity suspension and in particular for carrying out a method according to one of the preceding claims, comprising at least one agitator blade (14) that travels along the wall, a drive shaft (12) and a connecting element (34) which connects the stirring blade (14) to the drive shaft (12), characterized in that the connecting element (34) has an outer contour (38) which is intended to create a flow resistance a multi-dimensional flow of the fluid and/or the suspension generated by the stirring blade (14) in an operating state along a wave direction (16) in a near-wave area (18), which extends over an area of an imaginary cylinder whose Flaupter extension is essentially parallel to a Flaupter stretching of the drive shaft (12) and whose radius is at least 10% s radius of a stirred tank (42) corresponds to minimizing.

AMENDED SHEET (ARTICLE 19)

11. Agitating element device (10) according to claim 10, characterized in that the connecting element (34) has an at least substantially oval, preferably circular, cross section.

12. stirring system (40) with a stirred tank (42) and with a stirring element device (10) according to claim 10 or 11, in particular for carrying out a method according to any one of claims 1 to 9, wherein which the stirring blade (14) on the wall is arranged so that it can move at least partially within the stirring container (42) in a vicinity (44) of an inner wall (46) of the stirring vessel (42), with a maximum distance of the vicinity (44) from the inner wall (46) corresponds to at most 10% of a diameter of the stirred tank (42).

AMENDED SHEET (ARTICLE 19)