CN220634350U - Ternary precursor synthesis reaction device - Google Patents

Abstract

The application relates to ternary precursor synthesis reaction technical field discloses a ternary precursor synthesis reaction device, include: a reaction kettle; the hollow stirring shaft is arranged in the reaction kettle, a stirring paddle is arranged on the hollow stirring shaft, and a first channel for conveying a first material to the reaction kettle is formed in the hollow stirring shaft; the first conveying pipe is sleeved outside the hollow stirring shaft, a second channel for conveying a second material is formed between the first conveying pipe and the hollow stirring shaft, and a first channel discharge hole is positioned below the second channel discharge hole; the driving mechanism is connected with the hollow stirring shaft and drives the hollow stirring shaft to rotate so as to drive the stirring paddle to rotate. The discharge gate of cavity (mixing) shaft and the discharge gate of first conveyer pipe all are in the symmetrical distribution of cavity (mixing) shaft, and the material just symmetric distribution just in the initial of inflow reation kettle, and the material is rotatory along with the stirring rake symmetry, and the symmetry that the material flows makes the material distribute evenly in reation kettle, can shorten the homomixer time, effectively avoids causing the nucleation problem that local concentration is high and produce.

Description

Ternary precursor synthesis reaction device

Technical Field

The application relates to the technical field of ternary precursor synthesis reaction, in particular to a ternary precursor synthesis reaction device.

Background

The nickel-cobalt-manganese ternary material is widely applied to lithium ion batteries of digital electronic products, electric tools, electric bicycles and the like. The existing production method of the nickel-cobalt-manganese ternary precursor mainly adopts the steps of adding metal salt, liquid alkali and ammonia water into a reaction kettle body for preparation and generation.

The existing synthesis reaction device for preparing the ternary precursor mainly comprises a reaction kettle, a stirring device arranged in the reaction kettle and a pipeline for introducing materials into the reaction kettle, wherein the materials generally flow into the reaction kettle and can reach even concentration distribution after longer uniform mixing time, the materials still react in the period of time, and the nucleation problem caused by high local concentration is easily caused.

Therefore, how to shorten the mixing time and effectively avoid the nucleation problem caused by high local concentration is a problem to be solved by the person skilled in the art.

Disclosure of Invention

The purpose of this application is to provide a ternary precursor synthesis reaction unit for it is longer to solve the homomixer time, and the material takes place the reaction easily and causes local concentration height and the nucleation problem that produces.

For solving the technical problem, the application provides a ternary precursor synthesis reaction device, including:

a reaction kettle;

the hollow stirring shaft is arranged inside the reaction kettle, a stirring paddle is arranged on the hollow stirring shaft, and a first channel for conveying a first material to the reaction kettle is formed in the hollow stirring shaft;

the first conveying pipe is sleeved outside the hollow stirring shaft, a second channel for conveying a second material is formed between the first conveying pipe and the hollow stirring shaft, and a discharge hole of the first channel is positioned below a discharge hole of the second channel;

the driving mechanism is connected with the hollow stirring shaft and used for driving the hollow stirring shaft to rotate so as to drive the stirring paddles to rotate.

Optionally, the reactor further comprises a second conveying pipe and a ring pipe, wherein the ring pipe surrounds the hollow stirring shaft, a plurality of discharging holes are formed in the ring pipe, one end of the second conveying pipe is communicated with the ring pipe, and the other end of the second conveying pipe penetrates through the top of the reactor and extends out of the reactor.

Optionally, a first material outlet head is arranged at the discharge hole of the hollow stirring shaft, a second material outlet head is arranged at the discharge hole of the first conveying pipe, and the first material outlet head and/or the second material outlet head are in a horn shape.

Optionally, the stirring paddle includes first stirring paddle and second stirring paddle, first stirring paddle is located first discharging head top and be close to first discharging head, the second stirring paddle is located second discharging head below and be close to the second discharging head.

Optionally, the loop is located between the first stirring paddle and the second stirring paddle and is close to the first stirring paddle, and the opening direction of the discharge hole faces to the first stirring paddle.

Optionally, the side wall of the first material outlet head and/or the second material outlet head is provided with a plurality of holes uniformly distributed in the circumferential direction, and a plurality of the material discharging holes are uniformly distributed on the ring pipe.

Optionally, a plurality of baffles are arranged on the inner side wall of the reaction kettle.

Optionally, the actuating mechanism includes motor, action wheel, follow driving wheel and drive belt, the action wheel with the motor is connected, from the driving wheel cup joint in the nearly top of cavity (mixing) shaft, the action wheel with from the driving wheel passes through the drive belt connection.

Optionally, the overflow pipe is seted up to the lateral wall of reation kettle and be close to reation kettle's top, reation kettle's bottom is equipped with the bin outlet.

Optionally, a bearing is rotatably connected to the hollow stirring shaft near the top, and the bearing is used for suspending the hollow stirring shaft.

The application provides a ternary precursor synthesis reaction device, include: a reaction kettle; the hollow stirring shaft is arranged in the reaction kettle, a stirring paddle is arranged on the hollow stirring shaft, and a first channel for conveying a first material to the reaction kettle is formed in the hollow stirring shaft; the first conveying pipe is sleeved outside the hollow stirring shaft, a second channel for conveying a second material is formed between the first conveying pipe and the hollow stirring shaft, and a discharge hole of the first channel is positioned below a discharge hole of the second channel; the driving mechanism is connected with the hollow stirring shaft and is used for driving the hollow stirring shaft to rotate so as to drive the stirring paddles to rotate. The discharge gate of cavity (mixing) shaft and the discharge gate of first conveyer pipe all are in the symmetrical distribution of cavity (mixing) shaft, and the material just symmetric distribution just in the initial of inflow reation kettle, and the material is rotatory along with the stirring rake symmetry, and the symmetry that the material flows makes the material evenly distributed in reation kettle inside, can shorten the homomixer time, effectively avoids causing the high nucleation problem that produces of local concentration to promote the product uniformity.

Drawings

For a clearer description of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described, it being apparent that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a block diagram of a ternary precursor synthesis reaction apparatus according to an embodiment of the present disclosure;

FIG. 2 is a block diagram of a hollow stirring shaft and a first conveying pipe according to an embodiment of the present application;

FIG. 3 is a front view of a hollow stirring shaft and a first delivery tube provided in an embodiment of the present application;

FIG. 4 is a top view of a hollow stirring shaft and a first delivery tube provided in an embodiment of the present application;

FIG. 5 is a schematic view of a second pipe and collar according to an embodiment of the present disclosure;

FIG. 6 is a schematic view of a portion of a first stirring paddle and a first discharge head according to an embodiment of the disclosure;

FIG. 7 is a schematic view of a portion of a second stirring paddle and a second discharge head according to an embodiment of the present disclosure;

the reference numerals are as follows: 1 is a reaction kettle, 2 is a hollow stirring shaft, 3 is a first conveying pipe, 4 is a driving mechanism, 5 is a second conveying pipe, 6 is a circular pipe, 7 is a first material outlet head, 8 is a second material outlet head, 9 is a first stirring paddle, 10 is a second stirring paddle, 11 is a baffle, 12 is an overflow pipe, 13 is a material outlet, 14, a bearing, 15 is a hole, 41 is a motor, 42 is a driving wheel, 43 is a driven wheel, 44 is a driving belt, and 61 is a material outlet.

Detailed Description

The following description of the technical solutions in the embodiments of the present application will be made clearly and completely with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments herein without making any inventive effort are intended to fall within the scope of the present application.

The core of the application is to provide a ternary precursor synthesis reaction device for shorten the homomixer time, effectively avoid causing local concentration high and the nucleation problem that produces.

In order to provide a better understanding of the present application, those skilled in the art will now make further details of the present application with reference to the drawings and detailed description.

Fig. 1 is a structural diagram of a ternary precursor synthesis reaction device provided in an embodiment of the present application, as shown in fig. 1, the ternary precursor synthesis reaction device includes: a reaction kettle 1; the hollow stirring shaft 2 is arranged in the reaction kettle 1, a stirring paddle is arranged on the hollow stirring shaft 2, and a first channel for conveying a first material to the reaction kettle 1 is formed in the hollow stirring shaft 2; the first conveying pipe 3 is sleeved outside the hollow stirring shaft 2, a second channel for conveying a second material is formed between the first conveying pipe 3 and the hollow stirring shaft 2, and a discharge hole of the first channel is positioned below a discharge hole of the second channel; the driving mechanism 4 is connected with the hollow stirring shaft 2 and is used for driving the hollow stirring shaft 2 to rotate so as to drive the stirring paddles to rotate.

The shape and size of the reaction kettle 1 are not particularly limited in this embodiment, and as shown in fig. 1, the reaction kettle 1 may be cylindrical, and the bottom may be arc-shaped. FIG. 2 is a block diagram of a hollow stirring shaft and a first conveying pipe according to an embodiment of the present application; fig. 3 is a front view of a hollow stirring shaft and a first conveying pipe provided in the embodiment of the present application, as shown in fig. 2 to 3, the hollow stirring shaft 2 and the first conveying pipe 3 are both communicated with the reaction kettle 1 and are used for conveying a first material and a second material into the reaction kettle 1. Specifically, the first conveying pipe 3 passes through the top of the reaction kettle 1 in a sealing manner and extends into the reaction kettle 1, and the peripheral surface of the first conveying pipe 3 near the top is fixedly connected with the reaction kettle 1; the hollow stirring shaft 2 is coaxially assembled in the first conveying pipe 3, the top of the hollow stirring shaft 2 extends out of the first conveying pipe 3, the bottom of the hollow stirring shaft 2 extends out of the first conveying pipe 3 and extends to the near bottom of the reaction kettle 1, namely, a discharge hole at the bottom of the first conveying pipe 3 is positioned above a discharge hole at the bottom of the hollow stirring shaft 2, and a certain distance exists between the inner wall of the first conveying pipe 3 and the outer wall of the hollow stirring shaft 2. In the case of the ternary precursor synthesis reaction, a salt solution may be injected from an injection port at the top of the hollow stirring shaft 2, and an alkali solution may be injected from an injection port at the top of the first transfer pipe 3 to transfer the salt solution and the alkali solution to the reaction vessel 1, respectively. The embodiment of the application does not specifically limit the driving mechanism 4, and the driving mechanism 4 is connected with the hollow stirring shaft 2, drives the hollow stirring shaft 2 to rotate so as to drive the stirring paddles to rotate, and stirs and fully mixes materials in the reaction kettle 1. Regarding how to suspend the hollow stirring shaft 2, the bearing 14 can be rotatably connected to the near top of the hollow stirring shaft 2, and the bearing 14 is matched with some fixed components to suspend the hollow stirring shaft 2 in the reaction kettle 1, so that the abrasion of components caused by direct contact between the stirring shaft 2 and the reaction kettle 1 is reduced. Fig. 4 is a top view of a hollow stirring shaft and a first conveying pipe provided in an embodiment of the present application, as shown in fig. 4, discharge ports of the hollow stirring shaft 2 and the first conveying pipe 3 are symmetrically distributed around the hollow stirring shaft 2.

The embodiment of the application provides a ternary precursor synthesis reaction device, includes: a reaction kettle; the hollow stirring shaft is arranged in the reaction kettle, a stirring paddle is arranged on the hollow stirring shaft, and a first channel for conveying a first material to the reaction kettle is formed in the hollow stirring shaft; the first conveying pipe is sleeved outside the hollow stirring shaft, a second channel for conveying a second material is formed between the first conveying pipe and the hollow stirring shaft, and a discharge hole of the first channel is positioned below a discharge hole of the second channel; the driving mechanism is connected with the hollow stirring shaft and is used for driving the hollow stirring shaft to rotate so as to drive the stirring paddles to rotate. The discharge gate of cavity (mixing) shaft and the discharge gate of first conveyer pipe all are in the symmetrical distribution of cavity (mixing) shaft, and the material just symmetric distribution just in the initial of inflow reation kettle, and the material is rotatory along with the stirring rake symmetry, and the symmetry that the material flows makes the material evenly distributed in reation kettle inside, can shorten the homomixer time, effectively avoids causing the high nucleation problem that produces of local concentration to promote the product uniformity.

Based on the above embodiment, fig. 5 is a structural diagram of a second conveying pipe and a loop pipe provided in the embodiment of the present application, and as shown in fig. 5, the embodiment of the present application further includes a second conveying pipe 5 and a loop pipe 6, the loop pipe 6 is disposed around the hollow stirring shaft 2, a plurality of discharge holes 61 are disposed on the loop pipe 6, one end of the second conveying pipe 5 is communicated with the loop pipe 6, and the other end of the second conveying pipe 5 passes through the top of the reaction kettle 1 and extends out of the reaction kettle 1.

In view of the fact that more materials are required in some synthesis reactions, in this embodiment, the second conveying pipe 5 and the loop pipe 6 for conveying the third material are further provided, and of course, the number of the second conveying pipe 5 and the loop pipe 6 is not particularly limited, and may be set according to actual needs. In the synthesis reaction of the ternary material precursor, the ammonia solution may be fed into the reaction vessel 1 by the second feed pipe 5 and the loop 6. The hollow stirring shaft 2 is located in the middle of the ring canal 6, the ring canal 6 can be circular, a plurality of discharge holes 61 are formed in the ring canal 6, and specifically, the discharge holes 61 are uniformly distributed on the ring canal 6. Ammonia water is injected through an injection port at the top of the second conveying pipe 5, and the ammonia water enters slurry along the discharge holes 61 distributed in the annular pipe 6 and is dispersed to the whole kettle along with the flowing, so that the dispersion effect of materials in the slurry can be enhanced through the plurality of discharge holes 61 on the annular pipe 6.

Based on the above embodiments, fig. 6 is a schematic partial view of a first stirring paddle and a first discharge head provided in the embodiments of the present application, fig. 7 is a schematic partial view of a second stirring paddle and a second discharge head provided in the embodiments of the present application, as shown in fig. 6 and fig. 7, a first discharge head 7 is disposed at a discharge port of a hollow stirring shaft 2 in the embodiments of the present application, a second discharge head 8 is disposed at a discharge port of a first conveying pipe 3, and the first discharge head 7 and/or the second discharge head 8 are horn-shaped. The horn-shaped discharge head makes the position of the discharge hole have a certain degree of expansion so as to enhance the initial speed driven by the stirring paddle after the material flows into the reaction kettle 1.

Based on this, the side wall of the first discharge head 7 and/or the second discharge head 8 is provided with a plurality of holes 15 uniformly distributed in the circumferential direction, specifically, 2-4 rows of holes 15 may be uniformly distributed in the circumferential direction along the side wall of the trumpet-shaped discharge head. The open pore structure can increase the contact area of the material entering the slurry in the kettle, so as to enhance the dispersing effect of the material in the slurry.

Based on the above embodiment, as shown in fig. 6 and 7, the stirring paddle of the embodiment of the present application includes a first stirring paddle 9 and a second stirring paddle 10, where the first stirring paddle 9 is located above the first discharge head 7 and is close to the first discharge head 7, and the second stirring paddle 10 is located below the second discharge head 8 and is close to the second discharge head 8.

The first material outlet head 7 and the second material outlet head 8 in the embodiment of the application are distributed nearby respective stirring paddles, and are rapidly and uniformly dispersed and mixed by the stirring paddles when materials enter the reaction kettle 1, so that explosive nucleation caused by high concentration of local material liquid is further avoided, and the stability of product debugging is enhanced.

Further, the grommet 6 is located between the first paddle 9 and the second paddle 10 close to the first paddle 9, and the opening direction of the discharge hole 61 is directed toward the first paddle 9. Because of the action of gravity, the materials enter the reaction kettle 1 and have a downward movement trend, the opening direction of the discharge hole 61 faces the first stirring paddle 9 and is close to the first stirring paddle 9, the materials can be dispersed at the first time when the materials enter the reaction kettle 1, and the uniform mixing time can be shortened to further improve the consistency of products.

Based on the above embodiment, the driving mechanism 4 in the embodiment of the present application includes a motor 41, a driving wheel 42, a driven wheel 43 and a driving belt 44, the driving wheel 42 is connected with the motor 41, the driven wheel 43 is sleeved on the near top of the hollow stirring shaft 2, and the driving wheel 42 and the driven wheel 43 are connected through the driving belt 44.

The hollow stirring shaft 2 is driven to rotate by the motor 41, so that the stirring speed can be increased and the manpower can be saved compared with the manual rocking handle which drives the hollow stirring shaft 2 to rotate.

Based on the above embodiment, the overflow pipe 12 is provided on the side wall of the reaction kettle 1 and near the top of the reaction kettle 1; the bottom of the reaction kettle 1 is provided with a discharge port 13; the inner side wall of the reaction kettle 1 is provided with a plurality of baffles 11.

The discharge outlet 13 can be formed at the lowest point of the arc-shaped bottom of the reaction kettle 1, so that materials can be conveniently discharged from the discharge outlet 13 at the bottom after being uniformly mixed in the reaction kettle 1. The number of baffles 11 provided on the inner side wall of the reaction vessel 1 is not particularly limited. By providing the baffle 11 to convert tangential flow into axial and radial flow, the turbulence of the agitated liquid is increased, thereby improving the agitating effect; and in the stirring process, the liquid level of the material at the center of the stirring shaft is easy to form, the liquid level of the material at the position close to the inner wall of the reaction kettle 1 is high, namely, the phenomenon of vortex is commonly called, after the baffle plate 11 is added to the reaction kettle 1, the height of the material at the position close to the inner wall is obviously reduced, namely, the vortex is greatly weakened, and the stirring and mixing efficiency is improved to a certain extent.

For a better understanding of the examples herein, the process of preparing a micropowder-free ternary precursor using a synthesis reaction apparatus is described below.

1. Nickel sulfate, cobalt sulfate and manganese sulfate are mixed according to Ni: co: the molar ratio of Mn is 0:60:0.20, mixing nickel, cobalt and manganese with the total concentration of 2.0mol/L into a salt solution, and preparing NaOH alkaline solution with the concentration of 8mol/L and ammonia water solution with the concentration of 10 mol/L.

2. Deionized water is introduced into the reaction kettle to a position 0.3m below the overflow pipe 12 of the reaction kettle 1, stirring is started, ammonia water, alkali solution and protective gas are introduced, the ammonia concentration is regulated to 10g/L, the pH value is regulated to 11, and the temperature is kept at 65 ℃.

3. Introducing a salt solution through a hollow stirring shaft 2 at a flow rate of 60mL/min by a constant flow pump, keeping the flow rates of an ammonia water solution and an alkali solution in the process, controlling the ammonia concentration to be 8-9g/L and the pH value to be 10.5-11.5; wherein the alkali solution is introduced into the reaction kettle 1 through the first conveying pipe 3, and the ammonia solution is introduced into the reaction kettle 1 through the second conveying pipe 5 and the loop pipe 6.

4. The ammonia solution and the salt solution rotate along with the angular velocity of the hollow stirring shaft 2 into the kettle, so that the ammonia solution and the salt solution can be rapidly complexed and dispersed, and flow upwards along with the rotation trend under the action of the stirring paddles.

5. Simultaneously, the alkali solution at the discharge port of the first conveying pipe 3 flows into the kettle through the horn-shaped second discharge head 8, and rotates symmetrically and disperses along with the rotation of the stirring paddles, and the materials are fully mixed and contact to react to the required particle size under the action of the upper-layer second stirring paddles 10.

6. Stopping the machine, discharging, aging, washing and drying to obtain the required precursor particles.

Because the discharge port has excellent symmetry, the materials are uniformly distributed in the reaction kettle, and the uniform mixing time is shortened; the symmetry of the internal structure and the flow of the central stirring type reaction kettle is enhanced, the reaction non-uniformity in the kettle caused by the asymmetry of the flow is avoided, and the consistency of products is further improved. The salt and alkali discharge ports are respectively near the stirring paddles, so that the feeding solution can be rapidly and uniformly dispersed and mixed, explosive nucleation caused by high concentration of local feed liquid is avoided, and the stability of product debugging is enhanced. The ammonia solution discharge hole is positioned between the salt and alkali discharge holes and is close to the salt solution discharge hole, so that the ion diffusion distance is reduced, the coordination time of metal salt ions and ammonia is shortened, and the salt ammonia complexing speed is accelerated, thereby realizing efficient and full complexing reaction.

The above describes in detail a ternary precursor synthesis reaction device provided in the present application. In the description, each embodiment is described in a progressive manner, and each embodiment is mainly described by the differences from other embodiments, so that the same similar parts among the embodiments are mutually referred. It should be noted that it would be obvious to those skilled in the art that various improvements and modifications can be made to the present application without departing from the principles of the present application, and such improvements and modifications fall within the scope of the claims of the present application.

It should also be noted that in this specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

Claims (10)

1. A ternary precursor synthesis reaction device, comprising:

a reaction kettle (1);

the hollow stirring shaft (2) is arranged inside the reaction kettle (1), a stirring paddle is arranged on the hollow stirring shaft (2), and a first channel for conveying a first material to the reaction kettle (1) is formed in the hollow stirring shaft (2);

the first conveying pipe (3) is sleeved outside the hollow stirring shaft (2), a second channel for conveying a second material is formed between the first conveying pipe (3) and the hollow stirring shaft (2), and a discharge hole of the first channel is positioned below a discharge hole of the second channel;

the driving mechanism (4) is connected with the hollow stirring shaft (2) and is used for driving the hollow stirring shaft (2) to rotate so as to drive the stirring paddles to rotate.

2. The ternary precursor synthesis reaction device according to claim 1, further comprising a second conveying pipe (5) and a loop pipe (6), wherein the loop pipe (6) is arranged around the hollow stirring shaft (2), a plurality of discharge holes (61) are formed in the loop pipe (6), one end of the second conveying pipe (5) is communicated with the loop pipe (6), and the other end of the second conveying pipe (5) penetrates through the top of the reaction kettle (1) and extends out of the reaction kettle (1).

3. The ternary precursor synthesis reaction device according to claim 2, wherein a first material outlet head (7) is arranged at a material outlet of the hollow stirring shaft (2), a second material outlet head (8) is arranged at a material outlet of the first conveying pipe (3), and the first material outlet head (7) and/or the second material outlet head (8) are horn-shaped.

4. A ternary precursor synthesis reaction apparatus according to claim 3, wherein the stirring paddles comprise a first stirring paddle (9) and a second stirring paddle (10), the first stirring paddle (9) being located above the first discharge head (7) and close to the first discharge head (7), the second stirring paddle (10) being located below the second discharge head (8) and close to the second discharge head (8).

5. The ternary precursor synthesis reaction apparatus of claim 4, wherein the collar (6) is located between the first stirring paddle (9) and the second stirring paddle (10) and is close to the first stirring paddle (9), and the direction of the opening of the discharge hole (61) is toward the first stirring paddle (9).

6. A ternary precursor synthesis reaction device according to claim 3, wherein the side walls of the first discharge head (7) and/or the second discharge head (8) are provided with a plurality of holes (15) uniformly distributed circumferentially, and a plurality of the discharge holes (61) are uniformly distributed on the collar (6).

7. The ternary precursor synthesis reaction device according to claim 1, wherein a plurality of baffles (11) are arranged on the inner side wall of the reaction kettle (1).

8. The ternary precursor synthesis reaction device according to claim 1, wherein the driving mechanism (4) comprises a motor (41), a driving wheel (42), a driven wheel (43) and a transmission belt (44), the driving wheel (42) is connected with the motor (41), the driven wheel (43) is sleeved on the near top of the hollow stirring shaft (2), and the driving wheel (42) and the driven wheel (43) are connected through the transmission belt (44).

9. The ternary precursor synthesis reaction device according to claim 1, wherein an overflow pipe (12) is arranged on the side wall of the reaction kettle (1) and close to the top of the reaction kettle (1), and a discharge port (13) is arranged at the bottom of the reaction kettle (1).

10. The ternary precursor synthesis reaction apparatus of any one of claims 1 to 9, wherein a bearing (14) is rotatably connected to the near top of the hollow stirring shaft (2), and the bearing (14) is used for suspending the hollow stirring shaft (2).