Stirring device for bioreactor, stirring unit, bioreactor, production method and method for operating bioreactor

Abstract

The invention relates to a stirring device (10) for a bioreactor (1), comprising a stirring shaft (11) having a stirring unit (12), which has a stirring blade receptacle (20) and at least one stirring blade (13), which is arranged on the stirring blade receptacle (20) and can be moved between a first angular position and a second angular position, wherein the at least one stirring blade (13) is oriented at a first mounting angle (24) in a first angular position and at a second mounting angle (25) in a second angular position.

Description

Technical Field

[0001] The invention relates to a stirring device for a bioreactor, a stirring unit for upgrading a stirring shaft and a bioreactor. The invention also relates to a method for producing a stirring unit and / or a stirring device for a bioreactor, a method for producing a bioreactor and a method for operating a bioreactor. Background Art

[0002] A bioreactor, also commonly referred to as a fermenter, is a container in which certain microorganisms, cells or plants are cultured, preferably under the best possible, controllable and reproducible conditions, in order to obtain the cells themselves or parts thereof or their metabolites. To this end, a bioreactor encloses a reaction chamber in which a medium, in particular a culture medium, can be received.

[0003] Different types of bioreactors are known, for example so-called stirred tank reactors, also called stirred reactors. These bioreactors have a stirring function of different designs for mixing and in particular homogenizing the substances present in the reaction chamber, in particular the culture medium. This mixing and in particular homogenizing is achieved here, for example, by the rotational movement of at least one stirring blade mounted on a stirring shaft. For this purpose, the stirring shaft is rotated in particular by a drive unit.

[0004] Different types of stirring devices and their properties are known. The selection of a suitable stirring device type depends in particular on the stirring task, the toughness of the culture medium, the shear strength or also on the stirring device properties required for the process to be provided. For example, the following important stirring tasks can be distinguished: homogenization, deflocculation, heat transfer, suspension and emulsification. These stirring tasks rarely occur individually, so that different stirring tasks need to be performed simultaneously or in chronological order.

[0005] Different types of stirring devices are usually suitable or advantageous for different stirring tasks. Therefore, when selecting the type of stirring device, a compromise must usually be made between the "optimal" stirring device type for important process steps and general suitability for process steps that also occur but have a lesser influence on the yield and quality of the product.

[0006] Bioreactors should usually be operated in continuous process control. In particular, in order to avoid the risk of contamination, the stirring unit is usually not replaced during operation. In this regard, another challenge in selecting the type of stirring device is that the properties of the culture medium often change during the process, for example from Newtonian behavior with low viscosity to non-Newtonian flow characteristics with high structural viscosity. This can especially lead to an uneven viscosity distribution inside the bioreactor. This can have an adverse effect on, for example, homogenization and material transport.

[0007] Furthermore, such stirring devices are also installed in disposable bioreactors ("single-use" bioreactors). In this case, a single type of stirring device is usually selected and therefore can only be used in the process. Therefore, if a specific medium is to be processed in the bioreactor, the user must decide in advance on the type of stirring device. This means that the user can no longer change the fluid transport during the process, in particular to adapt it to changing parameters. Summary of the invention

[0008] Therefore, the object of the present invention is to provide an improved technical solution, which can solve at least one of the above problems. The object of the present invention is in particular to provide a technical solution, which can meet different stirring characteristics as required and can achieve continuous process control at the same time.

[0009] According to a first aspect, the above-mentioned purpose is achieved by a stirring device for a bioreactor according to claim 1, the stirring device comprising a stirring shaft, the stirring shaft having a stirring unit, the stirring unit having a stirring blade receiving portion and at least one stirring blade, the stirring blade being arranged on the stirring blade receiving portion and being able to move between a first angular position and a second angular position, wherein at least one stirring blade is oriented at a first mounting angle (Anstellwinkel) at the first angular position and oriented at a second mounting angle at the second angular position. Here, at least one stirring blade comprises a torsionally rigid rotating element, which is rotatably mounted on the stirring blade receiving portion between a first rotational position and a second rotational position. At least one stirring blade is oriented at a first mounting angle at the first rotational position and oriented at a second mounting angle at the second rotational position. The stirring blade receiving portion has at least one receiving opening, in which the rotating element is rotatably mounted and received between the first rotational position and the second rotational position. The stirring unit also includes a first stop and / or a second stop, the first stop limits the movement of at least one stirring blade at a first angular position along a first movement direction, and the second stop limits the movement of at least one stirring blade at a second angular position along a second movement direction, wherein the first stop and / or the second stop are preferably arranged on or formed by the stirring blade receiving portion, wherein the receiving opening forms the first stop and / or the second stop or is defined by the first stop and / or the second stop.

[0010] The invention is based on the recognition that, depending on the stirring characteristics to be achieved, different stirring devices can be used, such as pitched blade stirrers and disc stirrers. Pitched blade stirrers usually include oblique, mostly vertical stirring blades. In addition, pitched blade stirrers are essentially axially conveyed with a radial component. Pitched blade stirrers are therefore particularly suitable for suspension, homogenization and / or heat exchange. Pitched blade stirrers are particularly preferably used in shear-sensitive processes. Disc stirrers, also called "Rushton turbines", usually include vertically standing stirring blades. The stirring effect is based in particular on an outward flow that is axially drawn in from above and below. In this case, the outflowing liquid is usually subjected to high shear. Radial conveying can be used particularly advantageously for emulsification and degassing (Begasen).

[0011] In the technical solution described herein, a stirring device having a stirring shaft and a stirring unit is provided, and this stirring device realizes different stirring device types in one stirring device. Depending on the desired stirring characteristics, it is possible to choose between two stirring device types, and in particular to switch according to requirements. The switch between the two stirring device types can be achieved in particular in the following way: at least one stirring blade is arranged on the stirring blade receiving portion so that the stirring blade can move back and forth between a first angular position and a second angular position, so that at least one stirring blade can be oriented at different installation angles. Thus, for example, a pitched blade stirrer and a disc stirrer can be integrated in a stirring device and / or a stirring unit and used according to requirements.

[0012] Since the stirring device realizes two different stirring device types in one stirring device, the user can choose between the two stirring device types, in particular as required, in a continuous process. The user can thus switch between these stirring device types in a continuous process, thereby changing the fluid conveyance, in particular the fluid conveyance direction, in the process and in particular matching it to the medium to be conveyed.

[0013] Preferably, the stirring unit can be arranged or constructed on the stirring shaft. In particular, depending on the design and size, the stirring unit can be replaced together with the stirring shaft or can be mounted on the stirring shaft according to the desired stirring characteristics. In particular, the stirring unit can be detachably fastened to the stirring shaft. Thus, the stirring unit can be replaced according to the desired stirring characteristics. With this embodiment, for example, the stirring shaft can also be upgraded.

[0014] Here, the stirring blade receiving portion can be, for example, a part of the stirring shaft and / or be formed by the stirring shaft itself. Alternatively, the stirring blade receiving portion can be arranged on the stirring shaft as an additional component.

[0015] The stirring blade receiving portion can be particularly understood as a portion on which at least one stirring blade is arranged. Here, at least one stirring blade can be fastened to the stirring blade receiving portion or formed thereon. Here, the stirring blade receiving portion can be particularly configured so that at least one stirring blade can be movably arranged, in particular mounted on the stirring blade receiving portion.

[0016] Preferably, two, three or more stirring blades can be arranged on the stirring blade receiving portion. Particularly preferably, in particular six stirring blades can be arranged on the stirring blade receiving portion. Particularly preferred stirring characteristics are thereby achieved.

[0017] The stirring blade can be configured to be particularly right-angled, preferably rectangular. Alternatively, it can also be other shapes. It can be, for example, a shape with rounded corners. In particular, at least one stirring blade starts from the stirring blade receiving portion and therefore extends outwardly relative to the longitudinal axis of the stirring shaft.

[0018] In this article, the installation angle of at least one stirring blade can be particularly understood as the angle between the surface normal vector of at least one stirring blade, particularly at least one stirring blade and the plane of the virtual arrangement of the rotation axis orthogonal to the stirring shaft. Here, the installation angle preferably changes between greater than 0 ° and less than 180 °. All installation angles can be achieved thus.

[0019] The installation angle is especially suitable for the flow field Therefore, by changing the installation angle of at least one stirring blade during the process, the flow field can be changed.

[0020] By arranging at least one stirring blade movably on the stirring blade receiving portion, the first installation angle and / or the second installation angle can be adjusted, in particular depending on the direction of rotation of the stirring shaft. Thus, in particular by adjusting the direction of rotation of the stirring shaft, it is possible to switch between the two stirring device types. In particular, this switching can be carried out due to a force acting on the at least one stirring blade, preferably due to the rotation of the stirring shaft.

[0021] The stirring device described in this technical solution is preferably designed that at least one stirring blade is movably arranged on the stirring blade receiving portion, so that when a force acting in a first rotation direction opposite to the stirring shaft acts on the at least one stirring blade, the at least one stirring blade moves to a first angular position and / or is fixed at the first angular position without any fastening measures; and / or at least one stirring blade is movably arranged on the stirring blade receiving portion, so that when a force acting in a second rotation direction opposite to the stirring shaft acts on the at least one stirring blade, the at least one stirring blade moves to a second angular position and / or is fixed at the second angular position without any fastening measures.

[0022] Preferably, the stirring shaft can be driven in a first direction of rotation, in particular in a clockwise direction, and alternately in a second direction of rotation, in particular in a counterclockwise direction. By rotating the stirring shaft in the first or second direction of rotation, a force acting in particular opposite to the direction of rotation can act on at least one stirring blade. Thus, at least one stirring blade can be rotated to a corresponding angular position. The corresponding force can be generated in particular by the rotation of the medium and / or the stirring shaft.

[0023] In particular, if the movement of at least one stirring blade in a certain direction is restricted, the at least one stirring blade can be secured in one angular position without securing measures.

[0024] By means of this embodiment, a particularly simple stirring device can be provided which comprises two different stirring device types.

[0025] The stirring device includes a first stopper and / or a second stopper, wherein the first stopper limits the movement of at least one stirring blade at a first angular position along a first movement direction, and the second stopper limits the movement of at least one stirring blade at a second angular position along a second movement direction.

[0026] Preferably, the first direction of movement can be understood as a movement from the second angular position in the direction of the first angular position. Further preferably, the second direction of movement can be understood as a movement from the first angular position in the direction of the second angular position. Preferably, the first direction of movement and the second direction of movement can be designed substantially oppositely.

[0027] The first stop and / or the second stop are arranged on the stirring blade receiving portion or are formed by it. For example, an additional limiting element can be provided, which is arranged on the stirring blade receiving portion and forms the first stop and / or the second stop. For example, a plurality of additional limiting elements can also be provided, which form the first stop and / or the second stop and / or other stops, in particular the third stop and the fourth stop.

[0028] Therefore, the stopper should be understood as any design that can limit the movement along the first movement direction or the second movement direction. For example, a surface or an edge can form a corresponding stopper.

[0029] For example, the additional limiting element can be arranged to have a first face or a first edge and a second face or a second edge. The first face or the first edge can, for example, form a first stop. The second face or the second edge can, for example, form a second stop. Alternatively, the first stop and / or the second stop can also, for example, be formed by a protrusion or a spacer.

[0030] The rotating element can be configured, for example, on a side of at least one stirring blade facing the stirring shaft so that at least one stirring blade is connected to the stirring blade receiving portion. The rotating element can preferably be configured as a cylindrical shape. Thus, a rotatable installation can be particularly easily achieved.

[0031] The receiving opening can preferably be designed to be particularly circular, preferably annular, in order to rotatably mount the rotating element. Particularly preferably, the circular, preferably annular receiving opening can be defined by a first stop and / or a second stop in order to limit the movement in the first direction of movement and / or the second direction of movement.

[0032] Particularly preferably, a first limiting element can be provided, which is arranged on the stirring blade receiving portion and extends into the receiving opening, thereby forming a first stop and / or a second stop. Particularly preferably, a second limiting element is arranged on the stirring blade receiving portion and extends into the receiving opening, thereby forming a third stop and / or a fourth stop. Here, for example, the movement of at least one stirring blade along the first direction of movement can be limited by the first stop and the third stop. In particular, the movement of at least one stirring blade along the second direction of movement can be limited by the second stop and the fourth stop.

[0033] Particularly preferably, the rotating element can be fixed, in particular latched, in the receiving opening in a form-fitting manner. Thus, at least one stirring blade can be arranged and fastened particularly easily on the stirring blade receiving portion. For example, the rotating element can have a latching element here, which can be latched in the receiving opening.

[0034] The stirring blade according to this solution can advantageously have a blade region which is connected to the rotary element in a torsionally rigid manner.

[0035] In this case, the at least one receiving opening can preferably be formed radially and / or substantially orthogonally to the axis of rotation of the agitator shaft.

[0036] According to a particularly preferred embodiment of a stirring device for a bioreactor, the stirring device includes a stirring shaft and a stirring unit arranged on the stirring shaft, wherein the stirring unit includes a stirring blade receiving portion, at least one stirring blade and a rotating element torsionally rigidly connected to the stirring blade, and the rotating element is rotatably mounted on the stirring blade receiving portion between a first rotation position and a second rotation position; wherein at least one stirring blade is oriented at a first installation angle in the first rotation position and at a second installation angle in the second rotation position.

[0037] Thus, in operation, the mixing blade may be oriented at either the first mounting angle or the second mounting angle.

[0038] It is advantageous here that the rotating element can be rotatably mounted on the stirring blade receiving portion in such a way that when a force acting in a first rotational direction opposite to the stirring shaft acts on at least one stirring blade, the rotating element moves to a first rotational position and / or is fixed in the first rotational position without any fastening measures; and / or the rotating element is rotatably mounted on the stirring blade receiving portion in such a way that when a force acting in a second rotational direction opposite to the stirring shaft acts on at least one stirring blade, the rotating element moves to a second rotational position and / or is fixed in the second rotational position without any fastening measures.

[0039] The rotary element is preferably designed to be moved by rotation about its longitudinal axis in a first rotational direction from the second rotational position to the first rotational position and by rotation about its longitudinal axis in a second rotational direction from the first rotational position to the second rotational position.

[0040] Preferably, a first stop can be arranged on the stirring blade receiving portion, against which the rotating element can abut in the first rotational position. Particularly preferably, a second stop can be arranged on the stirring blade receiving portion, against which the rotating element can abut in the second rotational position.

[0041] In this case, the rotary element can preferably abut against a first stop in a first rotational position and against a second stop in a second rotational position.

[0042] Preferably, the rotary element can have a notch-shaped portion, which forms a first counter-stop that abuts against the first stop in the first rotational position. Preferably, the notch-shaped portion of the rotary element can form a second counter-stop that abuts against the second stop in the second rotational position. For example, the rotary element can have a substantially circular, in particular annular, notch-shaped portion with at least one flattened section, preferably with two flattened sections. The corresponding counter-stop can preferably be formed by the flattened section.

[0043] Particularly preferably, the notch-shaped portion of the rotary element can form the third counter-stop and / or the fourth counter-stop.

[0044] Preferably, the third counter-stop can abut against the third stop in the first rotational position. Particularly preferably, the fourth counter-stop can abut against the fourth stop in the second rotational position.

[0045] For example, the first matching stop may abut against the first stop in the first rotational position, and the second matching stop may abut against the third stop. Preferably, the first matching stop may abut against the second stop in the second position, and the second matching stop may abut against the fourth stop.

[0046] According to a particularly preferred embodiment, the receiving opening forms the first stop and / or the second stop or is limited by the first stop and / or the second stop.

[0047] Preferably, a disk limiting the receiving opening can be arranged on the stirring blade receiving portion, the disk forming the first stop and / or the second stop. Particularly preferably, the disk can be arranged on the outside or inside of the stirring blade receiving portion.

[0048] For example, the receiving opening may have an opening cutout and / or opening cutout shaped portion It forms the first stop and / or the second stop. Particularly preferably, the receiving opening can particularly have a circular, particularly annular opening cut-out-shaped portion. The corresponding stop can particularly be formed by a flattened area of ​​the circular, particularly annular opening cut-out-shaped portion.

[0049] According to a particularly preferred embodiment, the stirring device comprises a guide device which is designed to guide the movement of the stirring blade between the first angular position and the second angular position.

[0050] Particularly preferably, the rotating element may have a guide element (Führungselement), which is configured to guide the rotation of the rotating element between the first rotation position and the second rotation position. Preferably, the stirring blade receiving portion may have a corresponding guide mechanism (Führungsmittel), which is configured to cooperate with the guide element of the rotating element to guide the rotation of the rotating element between the first rotation position and the second rotation position. Preferably, the guide element and the guide mechanism can form a guide element system.

[0051] Preferably, the guide element can be configured as a protrusion, which protrudes radially from the surface, or substantially axially and / or axially-radially from the free end of the rotating element. Particularly preferably, the corresponding guide mechanism can be configured as a guide rail, which is arranged or configured on the stirring blade receiving portion or is formed by the edge of the receiving opening that defines the inner circumference, wherein the protrusion is guided in the guide rail.

[0052] Preferably, the guide element can be configured as a latching element, in particular a latching hook, which protrudes radially or axially or radially-axially from the free end of the rotating element. Preferably, the receiving opening can form a corresponding guide structure in which the guide element engages and latches.

[0053] The guide means and / or the guide element can advantageously form a first stop and / or a second stop or a first counter-stop and / or a second counter-stop.

[0054] Preferably, the corresponding guide means, in particular the guide rail, can be formed by an edge of the receiving opening formed by the receiving opening on the side facing away from the at least one stirring blade, wherein the guide element can be formed at the free end of the rotating element and engage behind the edge in the use state.

[0055] According to another preferred embodiment, the stirring blade receptacle and the stirring shaft can be formed in one piece.

[0056] In particular, the stirring blade receptacle can be formed by an intermediate piece arranged on the stirring shaft. Preferably, the intermediate piece can be fastened to the stirring shaft. Particularly preferably, the intermediate piece can be fastened to the stirring shaft in a detachable manner.

[0057] Preferably, the intermediate piece can be configured as a solid cylinder or a hollow cylinder or a ring.

[0058] The stirring unit can thus be connected in particular fixedly to the stirring shaft or can be connected detachably and can be replaced.

[0059] Preferably, the intermediate piece may have a snap hook. The snap hook is designed to fasten the stirring blade receiving portion to the stirring shaft. Preferably, the snap hook may extend substantially axially from the edge of the intermediate piece and may be designed to engage with a corresponding snap mechanism on the stirring shaft.

[0060] Particularly preferably, the intermediate piece is configured as a hollow cylinder with a central cylindrical opening. Preferably, the central cylindrical opening can be configured to arrange and / or fasten the stirring blade receptacle on the stirring shaft.

[0061] Preferably, the intermediate piece can be configured as a ring with a central annular opening. Preferably, the central annular opening can be configured to arrange and / or fasten the stirring blade receiving portion on the stirring shaft.

[0062] Particularly preferably, the stirring device can therefore be provided as a unit or comprise mutually detachable components, particularly a stirring shaft and a stirring unit and / or a stirring blade receiving portion and / or a stirring blade. Therefore, these mutually detachable components can advantageously be assembled and used as required.

[0063] In another preferred embodiment, the first installation angle is less than 90° or 90° relative to a plane virtually arranged orthogonal to the rotation axis of the stirring shaft; and / or the second installation angle is 90° or greater than 90° and less than 180° relative to a plane virtually arranged orthogonal to the rotation axis of the stirring shaft.

[0064] It is particularly advantageous that the first installation angle or the second installation angle is substantially 90° to a plane virtually arranged orthogonal to the rotation axis of the stirring shaft, and the corresponding other installation angle deviates from 90°, for example 60°. This makes it possible in particular to achieve that the stirring device includes a disk stirrer and a pitched blade stirrer, and thus different stirring characteristics can be achieved.

[0065] Another embodiment is that the stirring device is a pitch blade stirrer at two angular positions. For example, one installation angle can be 30° and the other installation angle can be 45°.

[0066] Preferably, the first mounting angle and the second mounting angle define different angular positions.

[0067] Preferably, the stirring shaft and / or the stirring unit at least partially consists of or comprises plastic, or consists of or comprises stainless steel. Alternatively, other or alternative materials that meet the requirements for use in a bioreactor can be used. Preferably, the stirring shaft and / or the stirring unit can be manufactured at least partially in an injection molding process or in an additive manufacturing process. For example, the stirring shaft and / or the stirring unit can be manufactured by 3D printing.

[0068] Preferably, the stirring shaft and / or the stirring blade receptacle and / or the stirring blade and / or optionally also the rotating element consists of or includes plastic, or consists of or includes stainless steel, and / or is manufactured by an injection molding process or by an additive manufacturing process.

[0069] Particularly preferably, the stirring device comprises at least one disk stirrer which is arranged on the stirring shaft at an axial distance from the stirring unit.

[0070] Preferably, the stirring device may include at least one pitched blade stirrer arranged on the stirring shaft axially spaced apart from the stirring unit.

[0071] Particularly preferably, the stirring device may include at least one additional stirring unit arranged on the stirring shaft axially spaced apart from the stirring unit, the additional stirring unit having an additional stirring blade receiving portion and at least one additional stirring blade, the additional stirring blade being arranged on the additional stirring blade receiving portion and being able to move between two different angular positions, at which the at least one additional stirring blade is oriented at different installation angles.

[0072] The further stirring unit arranged on the stirring shaft can preferably be configured in particular to be substantially identical to the aforementioned stirring shaft. Preferably, the further stirring unit can realize different installation angles, so that at least one further stirring blade can be oriented at a third installation angle and a fourth installation angle. Alternatively, at least one installation angle can be identical to the first installation angle and / or the second installation angle.

[0073] Particularly preferably, the further stirring unit can comprise a stirring blade having a torsionally rigid rotation element, which is rotatably mounted on the further stirring blade receptacle between two rotational positions in which the at least one further stirring blade is oriented at different mounting angles.

[0074] Particularly preferably, at least one further stirring unit and / or at least one disk stirrer and / or at least one pitched-blade stirrer can be arranged axially spaced apart from the stirring unit, so that the at least one further stirring unit and / or at least one disk stirrer and / or at least one pitched-blade stirrer only influences the flow in the medium from a defined filling height. In this way, at least one further stirring unit and / or at least one disk stirrer and / or at least one pitched-blade stirrer can be switched on as a function of the filling height. This embodiment is particularly advantageous because the volume and therefore also the filling height can be changed, in particular during the process. With changes in volume and filling height, the required stirring characteristics often also change.

[0075] Particularly preferably, the stirring device can include at least one further stirring unit, at least one stirring blade of which can be moved between the first mounting angle and / or the second mounting angle and / or the third mounting angle and / or the fourth mounting angle, in particular can be movably mounted. Preferably, at least one stirring blade of the further stirring unit can

[0076] - oriented at a first mounting angle in a first rotational position and oriented at a second mounting angle in a second rotational position, or

[0077] - oriented at a third mounting angle in the first rotational position and at a fourth mounting angle in the second rotational position, or

[0078] - oriented at the second mounting angle in the first rotational position and oriented at the first mounting angle in the second rotational position, or

[0079] - oriented at a first mounting angle in a first rotational position and at a third mounting angle in a second rotational position, or

[0080] - oriented at the third mounting angle in the first rotational position and oriented at the first mounting angle in the second rotational position, or

[0081] - oriented at a second mounting angle in a first rotational position and oriented at a third mounting angle in a second rotational position, or

[0082] - in the first rotational position, oriented at a third mounting angle, and in the second rotational position, oriented at a second mounting angle.

[0083] According to another aspect of the present invention, a stirring unit for upgrading a stirring shaft is provided, the stirring unit comprising a stirring blade receiving portion and at least one stirring blade, the stirring blade being arranged on the stirring blade receiving portion and being movable between a first angular position and a second angular position, wherein at least one stirring blade is oriented at a first mounting angle at a first angular position and oriented at a second mounting angle at a second angular position. Here, at least one stirring blade comprises a rotating element of torsion rigidity, which is rotatably mounted on the stirring blade receiving portion between a first rotation position and a second rotation position. At least one stirring blade is oriented at a first mounting angle at a first rotation position and oriented at a second mounting angle at a second rotation position. The stirring blade receiving portion has at least one receiving opening, in which the rotating element is rotatably mounted and received between the first rotation position and the second rotation position. The stirring unit also includes a first stop and / or a second stop, wherein the first stop limits the movement of at least one stirring blade at a first angular position along a first movement direction, and the second stop limits the movement of at least one stirring blade at a second angular position along a second movement direction. Here, the first stop and / or the second stop are preferably arranged on or formed by the stirring blade receiving portion, wherein the receiving opening forms the first stop and / or the second stop or is limited by the first stop and / or the second stop.

[0084] According to another aspect of the present invention, a bioreactor is provided, comprising: a top plate and a container, wherein the top plate and the container enclose a reaction chamber; a stirring device as described herein arranged in the reaction chamber, wherein a stirring shaft is rotatably mounted in a bearing around a rotation axis; and a driving unit arranged outside the reaction chamber and capable of being connected to the stirring shaft, the driving unit being designed to drive the stirring shaft along a first rotation direction and a second rotation direction.

[0085] The first rotation direction and the second rotation direction may in particular be opposite. In particular, the first rotation direction may define a rotation of the stirring shaft in a clockwise direction. Preferably, the corresponding second rotation direction may define a rotation of the stirring shaft in a counterclockwise direction.

[0086] Preferably, the top plate may have an inner side facing the reaction chamber and an outer side facing away from the reaction chamber, and the outer side has a plurality of interfaces.

[0087] Particularly preferably, the bioreactor may be a disposable bioreactor.

[0088] According to another aspect of the present invention, a method for manufacturing a stirring unit, in particular a stirring device as described herein and / or a stirring device as described herein is provided, comprising the following steps: providing a stirring blade receiving portion; providing at least one stirring blade; arranging at least one stirring blade on the stirring blade receiving portion so that at least one stirring blade is movable between a first angular position and a second angular position, thereby enabling at least one stirring blade to be oriented at a first installation angle at the first angular position and to be oriented at a second installation angle at the second angular position.

[0089] The stirring blade can advantageously be arranged on the stirring blade receiving portion, in this context in particular be fastened or formed on the stirring blade receiving portion.

[0090] In particular, the method may comprise providing a stirring shaft having a stirring blade receiving portion. Preferably, the stirring blade receiving portion may also be arranged on the stirring shaft.

[0091] Preferably, a torsionally rigid rotating element is arranged on the stirring blade receiving portion, in particular the rotating element is rotatably mounted between a first rotation position and a second rotation position so that at least one stirring blade can be oriented at a first mounting angle in the first rotation position and at a second mounting angle in the second rotation position.

[0092] According to another aspect of the present invention, a method for manufacturing a bioreactor, in particular a bioreactor as described herein, is provided, comprising the following steps: providing a container; providing a top plate; providing a stirring device as described herein; arranging the stirring device on the top plate; placing the top plate on the container; and connecting the top plate to the container to enclose a reaction chamber.

[0093] The method may preferably comprise producing a stirring device and / or a stirring unit, in particular as described herein.

[0094] Another step of the method may be, for example, providing a drive unit. The drive unit may preferably be arranged on the top plate and coupled to the stirring shaft.

[0095] According to another aspect of the present invention, a method for operating a bioreactor, in particular as described herein, is provided, the bioreactor comprising a stirring device, in particular as described herein and / or a stirring unit, in particular as described herein; the method comprising the following steps: adjusting a first drive parameter as required to drive the stirring shaft in a first rotation direction, thereby moving at least one stirring blade to a first angular position, wherein the at least one stirring blade is oriented at a first mounting angle at the first angular position; and / or adjusting a second drive parameter as required to drive the stirring shaft in a second rotation direction, thereby moving at least one stirring blade to a second angular position, wherein the at least one stirring blade is oriented at a second mounting angle at the second angular position, wherein the first drive parameter and the second drive parameter can be adjusted alternately.

[0096] Preferably, the first rotational direction may describe a clockwise rotation. Preferably, the second rotational direction may describe a counterclockwise rotation.

[0097] It is particularly advantageous that one aspect of the present invention may, for example, also relate to the application of the stirring device described herein and / or the stirring unit described herein, which is used to: adjust the first drive parameter as needed to drive the stirring shaft along the first rotation direction so that at least one stirring blade moves to a first angular position, and the at least one stirring blade is oriented at a first installation angle at the first angular position; and / or adjust the second drive parameter as needed to drive the stirring shaft along the second rotation direction so that at least one stirring blade moves to a second angular position, and the at least one stirring blade is oriented at a second installation angle at the second angular position, wherein the first drive parameter and the second drive parameter can be adjusted alternately.

[0098] With regard to advantages, variants and details of these further aspects and possible improvements thereof, reference is made to the previous description of the corresponding features. BRIEF DESCRIPTION OF THE DRAWINGS

[0099] The following will exemplarily describe exemplary embodiments with reference to the accompanying drawings, wherein:

[0100] Figure 1 An exemplary diagram of a stirring unit is shown;

[0101] Figure 2 An exemplary diagram of a stirring device is shown;

[0102] Figure 3 An exemplary diagram of a stirring unit is shown;

[0103] Figure 4 An exemplary cross-sectional view of a rotor blade receiving portion is shown;

[0104] Figure 5 An exemplary cross-sectional view of a stirring unit is shown;

[0105] Figure 6 An exemplary diagram of a bioreactor is shown;

[0106] Figure 7 An exemplary method for manufacturing a stirring unit is shown;

[0107] Figure 8 An exemplary method for making a bioreactor is shown; and

[0108] Fig. 9 An exemplary method for operating a bioreactor is shown.

[0109] In the figures, similar elements or elements having essentially the same function are denoted by the same reference signs. DETAILED DESCRIPTION

[0110] Figure 1 A and B in the figures respectively show exemplary illustrations of a stirring unit 12 having a stirring blade 13. The stirring unit 12 also has a stirring blade receiving portion 20, on which the stirring blade 13 is arranged. It should be particularly noted that the same stirring unit 12 is shown in A and B. The stirring blade 13 can move between a first angular position as shown in A and a second angular position as shown in B. The stirring blade 12 can be fastened to the stirring blade receiving portion or constructed thereon so as to be movably between the first angular position and the second angular position.

[0111] exist Figure 1 A shows the stirring blade 13 at a first installation angle 24. The first installation angle 24 is selected so that the stirring blade 13 is arranged obliquely, so that the stirring characteristics of the inclined blade stirrer can be met. The first installation angle 24 is less than 90° relative to a virtual plane arranged orthogonal to the rotation axis of the stirring shaft.

[0112] exist Figure 1 B shows the stirring blade 13 at the second installation angle 25. The second installation angle 25 is selected so that the stirring blade 13 is arranged substantially vertically, so that the stirring characteristics of the disk stirrer can be met. The second installation angle 25 is about 90° relative to the virtual plane arranged orthogonally to the rotation axis of the stirring shaft.

[0113] Except in Figure 1 In addition to the stirring unit 12 shown in FIG. 1 , the stirring device also includes a stirring shaft (in Figure 1The stirring device 13 is preferably provided with a stirring shaft 12 (not shown in the figure), to which the stirring unit 12 can be fastened or constructed, and the stirring device can be used in particular in a bioreactor. Here, the stirring shaft can preferably be connected to a drive unit of the bioreactor so that the stirring shaft can be driven in particular in a first rotational direction and / or a second rotational direction. The first rotational direction and the second rotational direction can be in particular opposite, preferably clockwise and counterclockwise. Due to the rotation of the stirring shaft during operation, in particular in the presence of a medium in the container of the bioreactor, a force opposite to the corresponding rotational direction acts on the stirring blade 13.

[0114] The stirring blade 13 is here particularly movably arranged on the stirring blade receiving portion 20, so that when a force acting opposite to the first rotation direction of the stirring shaft 11 acts on the stirring blade 13, at least one stirring blade 13 moves to the first angular position. In addition, by rotating the stirring shaft, the stirring blade 13 can also be fixed in the first angular position, in particular without fastening measures.

[0115] In particular, the stirring blade 13 is movably arranged on the stirring blade receiving portion 20, so that when a force acting opposite to the second rotation direction of the stirring shaft 11 acts on at least one stirring blade 13, at least one stirring blade 13 will move to the second angular position. In addition, by rotating the stirring shaft, the stirring blade 13 can also be fixed in the second angular position, in particular without fastening measures.

[0116] The views shown here and in a series of other views illustrate by way of example a stirring unit 12 with a single stirring blade 13 to highlight the structural and functional features of the stirring device. In particular, the design of the stirring unit is not limited to the examples shown. On the contrary, the stirring unit 12 may have a total of two, three or more stirring blades 13. Particularly preferably, a total of six stirring blades 13 are provided. Preferably, all stirring blades 13 of the stirring unit 12 are arranged on the stirring blade receiving portion so that they can move between a first angular position and a second angular position.

[0117] The movement of the stirring blade 13 between the first and second angular positions can be limited and / or guided in particular in the corresponding direction, so as to enable adjustment of the corresponding installation angle, in particular depending on the direction of rotation of the stirring shaft. Figures 3 to 5 Alternatively or additionally, a guide system can be provided.

[0118] Figure 2A part of a stirring device 10 is shown by way of example, comprising a stirring shaft 11 and a stirring unit 12, which can be constructed in particular as described above. The stirring blade receiving portion 20 of the stirring unit 12 can, for example, be a component of the stirring shaft 11. Alternatively, the stirring unit 12 can be an additional element, in particular, separable from the stirring shaft 11. Here, the stirring blade receiving portion can be fastened to the stirring shaft. For example, the stirring blade receiving portion 20 can be constructed as a ring, a solid cylinder or a hollow cylinder so as to be fastened to the stirring shaft 11. For example, the stirring blade receiving portion 20 can be arranged at one end of the stirring shaft that is opposite to the drive unit. Particularly preferably, a snap hook, for example, can be provided, which can achieve locking with the stirring shaft 11.

[0119] Figure 3 An exploded view of an exemplary variant of a stirring unit 12 is shown. The stirring unit 12 comprises a rotor blade receptacle 20 which is designed as a hollow cylindrical middle part.

[0120] The stirring blade 13 comprises a blade area and a torsionally rigid rotary element 14. The rotary element 14 is designed to be accommodated in a receiving opening 23 of a rotor blade receiving part 20. In particular, the rotary element 14 can be fastened in a rotatable manner in the receiving opening 23. Not shown in this figure are in particular fastening means, such as snap hooks, which can fasten the stirring unit 12 or the rotor blade receiving part 20 to a stirring shaft (not shown).

[0121] exist Figure 4 in and Figure 5 A or B in FIG. 1 shows a cross-sectional view of an exemplary variant of the rotor blade receiving portion 20. If the rotor blade receiving portion 20 is part of the stirring shaft, it can be particularly understood that Figure 3 A section through a part of a stirring shaft is shown. In this case, the rotor blade receiving part 20 is of hollow cylindrical design and has a receiving opening 23 in which the rotating element can be received.

[0122] In the example shown here, a first limiting element 28 and a second limiting element 29 are arranged on the inner circumference of the rotor blade receiving portion 20. The first limiting element 28 and the second limiting element 29 protrude into the region of the receiving opening 23, thereby limiting the receiving opening. In this case, the first limiting element 28 has a first stop 21 and a second stop 22, which are formed by the stop surface of the first limiting element 28 in the example shown here. The second limiting element 29 has a third stop 26 and a fourth stop 27, which are formed by the stop surface of the second limiting element 29 in the example shown here.

[0123] The first stopper 21 and the third stopper 26 can limit the rotational movement of the rotation element 14 received in the receiving opening 23 to a first rotational movement. Accordingly, the second stopper 22 and the fourth stopper 27 can limit the rotational movement of the rotation element 14 received in the receiving opening 23 to a second rotational movement opposite to the first rotational movement.

[0124] By Figure 4 and in Figure 5 The limiting elements 28, 29 shown in A or B of the embodiment of the present invention can provide a stop system. This type of stop system can in particular allow the stirring blade to be oriented at a specific installation angle. In addition, this also allows the stirring blade to be fastened without fastening measures at the corresponding installation angle. This provides a particularly simple embodiment of the stirring unit.

[0125] For example, according to an embodiment variant not shown, only the first limiting element 28 or the second limiting element 29 may be provided to correspondingly limit the movement of the rotating element in the rotation direction.

[0126] Figure 5 A and B in FIG. 1 respectively show exemplary illustrations of a stirring unit 12, which has a stirring blade 13. It should be particularly noted that the same stirring unit 12 is shown in A and B. Figure 5 A and Figure 5 B also shows a detailed view of the stirring unit marked with arrows. The stirring blade 13 can move between a first angular position as shown in A and a second angular position as shown in B. In order to realize this movement, the stirring blade 13 has a rotating element 14, which is rotatably mounted in the receiving opening 23. In order to fasten the rotating element 14 in the receiving opening 23, the rotating element has a first locking element 15 and a second locking element 16, which are locked in the receiving opening 23. In the example shown here, the locking elements 15, 16 are constructed at the end of the blade area of ​​the rotating element 14 facing away from the stirring blade 13 and engage with the edge of the receiving opening 23.

[0127] The rotary element 14 has a notch with a first counter-stop 17 and a second counter-stop 18 which can abut against the stops 21 , 22 , 26 , 27 depending on the respective rotational position.

[0128] exist Figure 5 In A, according to the rotation direction of the stirring shaft and the flow direction of the medium caused thereby, a force acts on the stirring blade 13, which is indicated by an arrow in the figure. Accordingly, the stirring blade moves to a first angular position and is fixed in this first angular position by a stop system without fastening measures.

[0129] like Figure 5As shown in A, the first counter-stop 17 abuts against the first stop 21 in the first rotational position. In addition, the second counter-stop 18 abuts against the third stop 26 in the first rotational position.

[0130] like Figure 5 As shown in FIG. 4B , in the second rotational position, the first counter-stop 17 abuts against the second stop 22 and the second counter-stop 18 abuts against the fourth stop 27 .

[0131] Figure 6 An exemplary bioreactor 1 is shown, comprising a container 3 and a top plate 2. In this example, the top plate 2 closes the container 3, thereby enclosing a reaction chamber. A stirring device 10 is arranged in the reaction chamber and comprises a stirring shaft 11 having a stirring unit 12. The stirring unit 12 has a stirring blade receiving portion 20 and six stirring blades 13 arranged on the stirring blade receiving portion. The stirring blade 13 is oriented at a first installation angle in the embodiment shown, so that the stirring unit 12 can realize the function of a pitched blade stirrer. In this embodiment, the stirring blade 12 can also be movably arranged between a first angular position and a second angular position, so that the stirring blade can be oriented at a first installation angle or a second installation angle, particularly according to the rotation direction of the stirring shaft 11. By rotating the stirring shaft 11, the stirring blade 12 can also be fastened at a corresponding angular position, particularly in the absence of fastening measures.

[0132] In addition, a drive unit 4 is arranged outside the reaction chamber on the connecting plate 2. The drive unit 4 is connected to the stirring shaft 11. According to this, the stirring shaft 11 can be driven in the first rotation direction or the second rotation direction. Through this embodiment, the stirring characteristics can be changed, especially according to the rotation direction, especially in a continuous process.

[0133] Figure 7 The method steps for manufacturing a stirring unit and / or a stirring device 40 of a stirring device as described herein are exemplarily shown. The method comprises the following steps: providing a stirring blade receiving portion 41; providing at least one stirring blade 42, and arranging the at least one stirring blade on the stirring blade receiving portion 43, so that the at least one stirring blade is movable between a first angular position and a second angular position, so that the at least one stirring blade can be oriented at a first installation angle in the first angular position, and can be oriented at a second installation angle in the second angular position. For example, the method may include additional manufacturing steps, in particular additional steps for manufacturing the stirring device. For example, the method may also include the following steps: providing a stirring shaft having a stirring blade receiving portion.

[0134] Figure 8The method steps for making a bioreactor are schematically shown. The method comprises providing a container 51 and providing a top plate 52. In step 53, a stirring device as described herein is provided and arranged on the top plate in step 54. Finally, the method places the top plate on the container in step 55 and finally connects the top plate to the container in step 56, thereby enclosing a reaction chamber.

[0135] Fig. 9 Exemplary method steps of a method for operating a bioreactor are shown. In step 61, a first drive parameter can be adjusted as needed, in particular according to the required stirring characteristics and / or medium characteristics. As a result, the stirring shaft is driven along a first rotation direction, so that at least one rotor blade of the stirring unit of the stirring device moves to a first angular position, at which the at least one stirring blade is oriented at a first installation angle. In step 62, a second drive parameter can be adjusted as needed, in particular according to the required stirring characteristics and / or medium characteristics, so as to drive the stirring shaft along a second rotation direction. As a result, at least one stirring blade can be moved to a second angular position, at which the at least one stirring blade is oriented at a second installation angle. Steps 61 and 62 can be adjusted alternately here, in particular in a process. As a result, the stirring characteristics can be matched within the process framework.

[0136] Reference numerals list

[0137] 1 Bioreactor

[0138] 2 Top plate

[0139] 3 Container

[0140] 4 Drivers

[0141] 10. Stirring device

[0142] 11. Stirring shaft

[0143] 12 Mixing unit

[0144] 13 Mixing blade

[0145] 14 Rotating element

[0146] 15 First locking element

[0147] 16 Second locking element

[0148] 17 First mating stop

[0149] 18 Second matching stop

[0150] 20 Mixing blade receiving portion

[0151] 21 First stop

[0152] 22 Second stop

[0153] 23 Accepting the opening

[0154] 24 First installation angle

[0155] 25 Second installation angle

[0156] 26 Third stop

[0157] 27 Fourth stop

[0158] 28 First limiting element

[0159] 29 Second limiting element

[0160] 30 Guiding element system

[0161] 31 Guide element

[0162] 32 Guidance Agency

[0163] 40 Method for manufacturing a stirring unit and / or a stirring device

[0164] 41 Provide a stirring blade receiving portion

[0165] 42 Provide at least one stirring blade

[0166] 43 Arrange at least one stirring blade on the stirring blade receiving portion

[0167] 50. Method for manufacturing a bioreactor

[0168] 51 Provide container

[0169] 52 Provide top plate

[0170] 53 Provide stirring device

[0171] 54 Arrange the stirring device on the top plate

[0172] 55 Place the top plate on the container

[0173] 56 Connect the top plate to the container

[0174] 60 Methods for operating a bioreactor

[0175] 61 Adjust the first drive parameters as needed

[0176] 62 Adjust the second driving parameters as needed.

Claims

1. A stirring device (10) for a bioreactor (1), comprising a stirring shaft (11), the stirring shaft having a stirring unit (12), the stirring unit comprising: - a stirring blade receiving portion (20), and at least one stirring blade (13) arranged on the stirring blade receiving portion (20) and movable between a first angular position and a second angular position, wherein the at least one stirring blade (13) is oriented at a first mounting angle (24) in the first angular position and at a second mounting angle (25) in the second angular position, wherein the at least one stirring blade (13) comprises a torsionally rigid rotating element (14) rotatably mounted on the stirring blade receiving portion (20) between a first rotational position and a second rotational position, wherein the at least one stirring blade (13) is oriented at the first mounting angle (24) in the first rotational position and is oriented at the second mounting angle (25) in the second rotational position, The stirring blade receiving portion (20) has at least one receiving opening (23), and the rotating element (14) is received in the receiving opening in a rotatable manner between the first rotation position and the second rotation position. The stirring unit also includes: - a first stop which limits the movement of the at least one stirring blade (13) in the first angular position along the first direction of movement, and / or - a second stop, which limits the movement of the at least one stirring blade (13) at the second angular position along the second movement direction, wherein, preferably, the first stop and / or the second stop are arranged on the stirring blade receiving portion or are formed by the stirring blade receiving portion, wherein the receiving opening (23) forms the first stop (21) and / or the second stop (22) or is limited by the first stop (21) and / or the second stop (22).

2. A stirring device (10) according to claim 1, -in, The at least one stirring blade (13) is movably arranged on the stirring blade receiving portion (20), so that when a force acting opposite to the first rotation direction of the stirring shaft (11) acts on the at least one stirring blade (13), the at least one stirring blade (13) moves to the first angular position and / or is fixed in the first angular position without fastening measures, and / or -Wherein, the at least one stirring blade (13) is movably arranged on the stirring blade receiving portion (20) so that when a force acting in the opposite direction to the second rotation direction of the stirring shaft (11) acts on the at least one stirring blade (13), the at least one stirring blade (13) moves to the second angular position and / or is fixed at the second angular position without any fastening measures.

3. The stirring device (10) according to at least one of the preceding claims, wherein: The rotary element (14) is fixed in a form-fitting manner, in particular latched, in the receiving opening (23).

4. Stirring device (10) according to at least one of the preceding claims, comprising a guide device designed to guide the movement of the stirring blade between the first angular position and the second angular position.

5. The stirring device (10) according to at least one of the preceding claims, wherein: The stirring blade receiving portion (20) and the stirring shaft (11) are constructed in one piece, or - the stirring blade receiving portion (20) is formed by an intermediate piece arranged on the stirring shaft (11), Wherein, the intermediate piece is preferably fastened to the stirring shaft (11), The intermediate piece is preferably configured as a solid cylinder or a hollow cylinder or a ring.

6. A stirring device (10) according to at least one of the preceding claims, in, The first installation angle (24) is less than 90° or 90° relative to a plane virtually arranged orthogonal to the rotation axis of the stirring shaft (11), and / or The second installation angle (25) is 90° or greater than 90° and less than 180° relative to a virtually arranged plane orthogonal to the rotation axis of the stirring shaft (11).

7. The stirring device (10) according to at least one of the preceding claims, wherein: The stirring shaft (11) and / or the stirring unit (12) are at least partially made of or include plastic, or made of or include stainless steel, Preferably, the stirring shaft (11) and / or the stirring unit (12) are at least partially manufactured by an injection molding process or an additive manufacturing process.

8. The stirring device (10) according to at least one of the preceding claims, comprising: at least one disk stirrer arranged on the stirrer shaft (11) axially spaced apart from the stirrer unit (12), and / or - at least one pitched-blade stirrer arranged on the stirring shaft (11) axially spaced apart from the stirring unit (12), and / or - at least one further stirring unit arranged on the stirring shaft (11) axially spaced apart from the stirring unit (12), the further stirring unit having a further stirring blade receiving portion and at least one further stirring blade, the further stirring blade being arranged on the further stirring blade receiving portion and being movable between two different angular positions, the at least one further stirring blade being oriented at different mounting angles at the angular positions.

9. A stirring unit (12) for upgrading a stirring shaft (11), comprising: - a stirring blade receiving portion (20), and at least one stirring blade (13) which is arranged on the stirring blade receiving portion (20) and is movable between a first angular position and a second angular position, wherein the at least one stirring blade (13) is oriented at a first mounting angle (24) in the first angular position and at a second mounting angle (25) in the second angular position; wherein the at least one stirring blade (13) comprises a torsionally rigid rotating element (14) rotatably mounted on the stirring blade receiving portion (20) between a first rotational position and a second rotational position, wherein the at least one stirring blade (13) is oriented at the first mounting angle (24) in the first rotational position and is oriented at the second mounting angle (25) in the second rotational position, The stirring blade receiving portion (20) has at least one receiving opening (23), and the rotating element (14) is received in the receiving opening in a rotatable manner between the first rotation position and the second rotation position. The stirring unit also includes: - a first stop which limits the movement of the at least one stirring blade (13) in the first angular position along the first direction of movement, and / or - A second stop, which limits the movement of the at least one stirring blade (13) at the second angular position along the second movement direction, wherein, preferably, the first stop and / or the second stop are arranged on the stirring blade receiving portion or are formed by the stirring blade receiving portion; wherein the receiving opening (23) forms the first stop (21) and / or the second stop (22) or is limited by the first stop (21) and / or the second stop (22).

10. A bioreactor (1), comprising: - a top plate (2) and a container (3), wherein the top plate (2) and the container (3) enclose a reaction chamber, - a stirring device (10) arranged in the reaction chamber according to at least one of the preceding claims 1 to 8, wherein the stirring shaft (11) is rotatably mounted in a bearing about an axis of rotation, A drive unit (4) arranged outside the reaction chamber and connectable to the stirring shaft (11), the drive unit being designed to drive the stirring shaft (11) in a first rotational direction and in a second rotational direction.

11. A method for producing a stirring unit, in particular a stirring unit according to claim 9, a stirring device and / or in particular a stirring device (40) according to at least one of claims 1 to 8, comprising the following steps: - providing a stirring blade receiving portion (41), - providing at least one stirring blade (42), - The at least one stirring blade is arranged on the stirring blade receiving portion (43) so that the at least one stirring blade can move between a first angular position and a second angular position, so that the at least one stirring blade can be oriented at a first installation angle in the first angular position and at a second installation angle in the second angular position.

12. A method for producing a bioreactor (50), in particular a bioreactor according to claim 10, comprising the following steps: - providing a container (51), - providing a top plate (52), - providing a stirring device (53) according to any one of claims 1 to 8, - arranging the stirring device on the top plate (54), - placing the top plate on the container (55), and - Connecting the top plate to the container (56) to enclose a reaction chamber.

13. A method for operating a bioreactor (60), in particular a bioreactor according to claim 10, comprising a stirring device, in particular a stirring device and / or a stirring unit according to at least one of claims 1 to 8, in particular a stirring unit according to claim 9, the method comprising the following steps: - adjusting a first drive parameter (61) as required so as to drive the stirring shaft in a first rotational direction so that at least one stirring blade moves to a first angular position, wherein the at least one stirring blade is oriented at a first mounting angle; and / or - adjusting a second drive parameter (62) as required in order to drive the stirring shaft in a second rotational direction so that the at least one stirring blade moves to a second angular position in which the at least one stirring blade is oriented at a second mounting angle, The first driving parameter and the second driving parameter can be adjusted alternately.

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