Biochar carrier for regulating and controlling microflora of seaweed bed and preparation device of biochar carrier

Abstract

The invention relates to the technical field of biochar preparation, in particular to a biochar carrier for regulating and controlling seaweed bed microflora and a preparation device thereof.The biochar carrier comprises an inner core, and the surface of the inner core is sequentially coated with a middle layer and a shell from inside to outside. The preparation device comprises a shell, a feeding port, a charging port and a discharging port are formed in the shell, a rubber plug is arranged at the discharging port, a partition plate is arranged in the shell and divides the interior of the shell into a driving cavity and a processing cavity, a telescopic part is arranged in the processing cavity, a driving frame is arranged on an output shaft of the telescopic part, and a crushing assembly is arranged on the driving frame; a through hole is formed in the partition plate, and a stirring assembly is arranged in the through hole. The seaweed plant source biochar is used as an inner core, so that the surface pore structure of the seaweed plant source biochar is matched with the natural habitat environment of seaweed rhizosphere microorganisms, and the probiotics are efficiently loaded. Meanwhile, a multiple slow-release structure generated by the hydrogel protective layer and the magnetic porous silicon dioxide shell can also reduce the loss of microorganisms and improve the environmental adaptability.

Description

Technical Field

[0001] This invention relates to the field of biochar preparation technology, specifically to a biochar carrier for regulating the microbial community of seagrass beds and its preparation device. Background Technology

[0002] Biochar carriers for regulating seagrass bed microbial communities are porous solid particulate materials prepared from carbon-rich biomass, such as forest residue, agricultural straw, and livestock manure, through high-temperature pyrolysis under anaerobic or hypoxic conditions. The well-developed porous structure of biochar provides habitat for microorganisms, while its oxygen-containing active groups adsorb nutrients for microbial use. Furthermore, biochar can regulate sediment pH, optimizing the microbial living environment. This directly improves the microbial microenvironment and indirectly regulates plant root metabolism, thereby synergistically enhancing the function and ecological stability of the seagrass bed microbial community.

[0003] Existing technologies, such as agricultural waste biochar, utilize the porous structure of their surfaces to adsorb heavy metals like lead and cadmium from sediments, indirectly optimizing the microbial living environment. Simultaneously, they can neutralize the acidic environment of seagrass bed sediments, thereby enhancing the activity of nitrogen-fixing bacteria.

[0004] While the aforementioned biochar can improve the growth environment of seaweed, it relies on a single porous structure to adsorb microorganisms and lacks a slow-release mechanism. This leads to a problem during use: probiotics are easily lost with tides or water currents, making it difficult to maintain a stable functional microbial community. Therefore, there is a need to propose a biochar carrier with multiple slow-release mechanisms and its preparation device. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a biochar carrier and its preparation apparatus for regulating the microbial community in seagrass beds. This device uses seagrass-derived biochar as a core, matching its surface pore structure to the natural habitat of seagrass rhizosphere microorganisms, thereby efficiently loading probiotics. Simultaneously, the multiple slow-release structure generated by the hydrogel protective layer and the magnetic porous silica shell reduces microbial loss and improves its environmental adaptability.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: a biochar carrier for regulating the microbial community of seagrass beds, comprising a core, wherein the surface of the core is covered with an intermediate layer and a shell from the inside out.

[0007] The core includes seaweed-derived biochar, which is produced by the pyrolysis of seaweed raw materials and is used to load probiotics.

[0008] The intermediate layer includes a hydrogel protective layer, which is formed by calcium ion crosslinking of sodium alginate and chitosan, and is used to protect probiotics and provide a slow-release environment.

[0009] The shell consists of a magnetic porous silica shell, inside which nano-Fe3O4 particles and seaweed rhizosphere signaling molecules are added to provide physical protection for the biochar carrier.

[0010] Furthermore, the method for preparing the biochar carrier includes the following steps:

[0011] Step 1, raw material pretreatment: Waste seaweed salvaged from degraded seaweed beds is used as raw material. After washing with distilled water, it is subjected to pyrolysis. After pyrolysis is completed, the raw material is placed in a preparation device, where it is crushed and sieved by the crushing component to obtain biochar particles.

[0012] Step 2, intermediate layer coating: Sodium alginate and chitosan are placed in the preparation device, and a sodium alginate-chitosan mixture is prepared by the stirring component in the preparation device. Biochar particles are added to the sodium alginate-chitosan mixture, and then calcium chloride solution is added to it for cross-linking and curing to form a hydrogel layer, which serves as an intermediate layer to coat the biochar particles, thus obtaining wet particles.

[0013] Step 3, Shell Preparation: The wet particles are dried to obtain gel particles. At the same time, tetraethyl orthosilicate is mixed with anhydrous ethanol, and nano Fe3O4 particles and seaweed rhizosphere signal molecules are added to obtain a mixed solution. Dilute ammonia is added to the mixed solution and stirred continuously until the mixed solution is stirred into a sol. Then, the gel particles are immersed in the sol for coating. After the coating is completed, they are taken out and dried to allow the tetraethyl orthosilicate to be completely hydrolyzed and condensed to form a porous silica shell.

[0014] Step 4, Probiotic Loading: Mix the probiotic liquid with the nutrient solution, and adsorb the probiotic liquid into the pores of the biochar core to achieve probiotic loading.

[0015] Furthermore, in step one, the pyrolysis temperature is 400-600℃ during the pyrolysis operation.

[0016] Furthermore, in step one, when sieving the raw materials, the sieved particle size is 0.25mm-2mm.

[0017] Furthermore, in step three, the concentration of the dilute ammonia solution is 2%-4%.

[0018] Furthermore, in step four, the probiotics are selected from one or more of nitrogen-fixing bacteria, phosphate-solubilizing bacteria, and pollutant-degrading bacteria; the nutrient solution is selected from one of phosphate buffer and Tris-HCl buffer.

[0019] Furthermore, in step four, the probiotic loading is performed using a vacuum impregnation method.

[0020] Furthermore, an apparatus for preparing a biochar carrier for regulating the microbial community of seagrass beds includes a controller and a shell. The top of the shell has a feed inlet, and the side wall of the shell has a feeding port and a discharge port. A rubber plug is detachably connected to the discharge port. A partition is fixedly connected to the inner side wall of the shell, which divides the interior of the shell into a driving chamber and a processing chamber from top to bottom. A telescopic component is fixedly connected to the bottom wall of the processing chamber. The controller is used to control the opening and closing of the telescopic component. A drive frame is coaxially fixedly connected to the output shaft of the telescopic component. A crushing component for crushing raw materials is provided at the end of the drive frame away from the output shaft of the telescopic component.

[0021] The partition has through holes, and a stirring component for stirring the mixed solution is installed inside the through holes.

[0022] Furthermore, the crushing assembly includes a crushing box fixedly connected to the top of the partition plate. The top of the crushing box has a discharge port located directly below the feed port. A crushing plate is laterally slidably fitted on the inner side wall of the crushing box. One end of the drive frame away from the output shaft of the telescopic component extends through the side wall of the crushing box and into the interior of the crushing box, where it is fixedly connected to the crushing plate. A screen is fixedly connected to the bottom of the crushing box. A discharge port is opened on the partition plate. The crushing box communicates with the processing chamber through the screen and the discharge port. A cleaning brush is fixedly connected to the bottom of the crushing plate.

[0023] Furthermore, the stirring assembly includes a stirring disc rotatably fitted at the through hole, a transmission block eccentrically fixedly connected to the top of the stirring disc, the transmission block being located inside the drive frame and rotating and slidingly fitted with the drive frame, a stirring rod fixedly connected to the bottom of the stirring disc, the end of the stirring rod away from the stirring disc being rotatably fitted with the bottom wall of the outer shell, and stirring blades fixedly connected to the stirring rod along its lower circumference.

[0024] The technical principles of the above solution are as follows:

[0025] Workers place the raw materials into the shell through the feed inlet, allowing the materials to enter the crushing component. Then, the controller controls the telescopic output shaft to reciprocate, causing the drive frame to move laterally back and forth. This, in turn, causes the drive frame to operate the crushing component, which then crushes the raw materials.

[0026] During this process, the drive frame will also drive the stirring component to operate, and the stirring component will mix sodium alginate and chitosan.

[0027] The above approach has the following beneficial effects:

[0028] 1. This invention uses seaweed-derived biochar as its core, matching its surface pore structure to the natural habitat of seaweed rhizosphere microorganisms, thereby efficiently loading probiotics. Simultaneously, the multiple slow-release structure generated by the hydrogel protective layer and the magnetic porous silica shell reduces microbial loss and improves its environmental adaptability.

[0029] 2. This invention uses waste seagrass from degraded seagrass beds as raw material, solving the waste disposal problem during seagrass bed restoration while simultaneously converting it into biochar, achieving a circular economy model of treating waste with waste. Furthermore, sodium alginate and chitosan form a three-dimensional network through calcium ion cross-linking, and probiotics are loaded using a vacuum impregnation method, allowing microorganisms to be encapsulated within the dynamic pores of the hydrogel, reducing the microbial loss problem caused by the burst release of traditional biochar.

[0030] 3. This invention uses a drive frame to move the crushing plate laterally in a reciprocating motion, which, in conjunction with a screen, enables the graded crushing of raw materials. The unblocking brush moves synchronously with the crushing plate, cleaning the screen in real time, reducing the possibility of clogging and ensuring stable crushing efficiency. Simultaneously, the crushing plate's movement also drives the stirring component, enabling simultaneous stirring of sodium alginate and chitosan, improving the continuity of the device's operation.

[0031] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of a biochar carrier for regulating the microbial community of seagrass beds according to the present invention;

[0033] Figure 2 This is a schematic diagram illustrating the manufacturing steps of the biochar carrier for regulating the microbial community of seagrass beds according to an embodiment of the present invention.

[0034] Figure 3 This is an isometric schematic diagram of an embodiment of the apparatus for preparing biochar carriers for regulating microbial communities in seagrass beds according to the present invention.

[0035] Figure 4 This is an isometric view of the internal structure of the apparatus for preparing biochar carriers for regulating microbial communities in seagrass beds according to an embodiment of the present invention.

[0036] Figure 5 This is a side cross-sectional schematic diagram of the crushing component in an embodiment of the apparatus for preparing biochar carriers for regulating microbial communities in seagrass beds according to the present invention.

[0037] The reference numerals in the accompanying drawings of the instruction manual include: 1. shell; 2. rubber stopper; 3. partition plate; 4. drive frame; 5. electric telescopic rod; 6. crushing box; 7. crushing plate; 8. screen; 9. stirring plate; 10. transmission block; 11. stirring rod; 12. stirring blade; 13. core; 14. intermediate layer; 15. outer shell. Detailed Implementation

[0038] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0040] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0041] The following detailed description illustrates the specific implementation method:

[0042] Implementation, for example Figure 1 As shown: A biochar carrier for regulating the microbial community of seagrass beds includes a core 13, the surface of which is covered from the inside out with an intermediate layer 14 and a shell 15.

[0043] The core 13 includes seaweed-derived biochar, which is obtained by pyrolysis of seaweed raw materials and is used to support probiotics; the middle layer 14 includes a hydrogel protective layer, which is formed by calcium ion crosslinking of sodium alginate and chitosan, and is used to protect probiotics and provide a slow-release environment; the shell 15 includes a magnetic porous silica shell 15, which contains nano Fe3O4 particles and seaweed rhizosphere signaling molecules to provide physical protection for the biochar carrier.

[0044] like Figure 2 As shown, the method for preparing the biochar carrier includes the following steps:

[0045] Step 1, Raw Material Pretreatment: Workers use waste seaweed salvaged from degraded seaweed beds as raw material. The raw material is washed with distilled water. After washing, it is pyrolyzed at 400-600℃. After pyrolysis, the raw material is removed and placed in a preparation device. The raw material is crushed and sieved by a crushing component in the preparation device to obtain biochar particles with a particle size of 0.25mm-2mm. In this embodiment, the raw material is placed in a tube furnace for pyrolysis.

[0046] Step 2, Intermediate Layer 14 Coating: After the biochar particles are prepared, the staff put sodium alginate and chitosan into the preparation device, and prepared a sodium alginate-chitosan mixture using the stirring component in the preparation device. The biochar particles are then added to the sodium alginate-chitosan mixture. At the same time, calcium chloride solution is added to the sodium alginate-chitosan mixture to crosslink and solidify the sodium alginate and chitosan with the calcium ions in the calcium chloride solution, forming a hydrogel layer to coat the biochar particles, thus obtaining wet particles.

[0047] Step 3, Preparation of Shell 15: The wet particles are dried to obtain gel particles. During this process, tetraethyl orthosilicate is mixed with anhydrous ethanol, and nano-Fe3O4 particles and seaweed rhizosphere signal molecules are added to prepare a mixed solution. Then, 2%-4% dilute ammonia solution is added to the mixed solution and stirred continuously until a sol is formed. After the sol is prepared, the gel particles are immersed in the sol for coating. After coating, they are removed and dried to allow the tetraethyl orthosilicate to completely hydrolyze and condense, forming a porous silica shell 15.

[0048] Step four, probiotic loading: First, the staff mixes the probiotic solution with the nutrient solution. Then, using a vacuum impregnation method, the probiotic solution mixed with the nutrient solution is adsorbed into the pores of the biochar core 13, thus loading the probiotics and completing the preparation of the biochar carrier. The probiotics selected are one or more of nitrogen-fixing bacteria, phosphate-solubilizing bacteria, and pollutant-degrading bacteria; the nutrient solution is either phosphate buffer or Tris-HCl buffer.

[0049] like Figure 3 and Figure 4As shown, the preparation device in this embodiment includes a controller and a housing 1. The top of the housing 1 has a feed inlet, and the side walls of the housing 1 have a feeding port and a discharge port. A rubber plug 2 is detachably engaged at the discharge port. A partition 3 is welded to the inner side wall of the housing 1, dividing the interior of the housing 1 into a driving chamber and a processing chamber from top to bottom. A telescopic component is screwed and fixedly connected to the bottom wall of the processing chamber. The controller controls the opening and closing of the telescopic component. A drive frame 4 is coaxially screwed and fixedly connected to the output shaft of the telescopic component. The crushing component is located at the end of the drive frame 4 away from the output shaft of the telescopic component. In this embodiment, an electric telescopic rod 5 is used as the telescopic component.

[0050] like Figure 5 As shown, the crushing assembly includes a crushing box 6 welded to the top of the partition 3. The top of the crushing box 6 has a discharge port located directly below the feed port. A crushing plate 7 is slidably fitted on the inner side wall of the crushing box 6. One end of the drive frame 4, away from the output shaft of the electric telescopic rod 5, extends through the side wall of the crushing box 6 and into the interior of the crushing box 6, forming an integral part with the crushing plate 7. A screen 8 is embedded in the bottom of the crushing box 6. A discharge port is opened on the partition 3. The crushing box 6 is connected to the processing chamber through the screen 8 and the discharge port. A cleaning brush is fixedly bonded to the bottom of the crushing plate 7.

[0051] Specifically, the staff put the raw materials into the crushing box 6 through the feed inlet and discharge outlet, and at the same time add sodium alginate and chitosan into the outer shell 1 through the feeding port. Then, the controller controls the output shaft of the electric telescopic rod 5 to reciprocate, which drives the drive frame 4, which is fixed to it with screws, to reciprocate laterally. The drive frame 4 then drives the crushing plate 7, which is integrally formed with it, to slide laterally back and forth in the crushing box 6, squeezing and crushing the raw materials in the crushing box 6. The crushed raw materials can enter the processing chamber through the screen 8 and the discharge port.

[0052] During this process, since the unblocking brush is located at the bottom of the crushing plate 7, the crushing plate 7 can also drive the unblocking brush to move laterally back and forth with it during the horizontal reciprocating motion. The unblocking brush cleans the screen 8 to reduce the clogging of the screen 8.

[0053] The partition 3 has a through hole, and the stirring component is located inside the through hole.

[0054] The stirring assembly includes a stirring disc 9 rotatably fitted at the through hole. A transmission block 10 is integrally formed eccentrically on the top of the stirring disc 9. The transmission block 10 is located inside the drive frame 4 and rotates and slides with the drive frame 4. A stirring rod 11 is welded to the bottom of the stirring disc 9. The end of the stirring rod 11 away from the stirring disc 9 is rotatably fitted with the bottom wall of the outer shell 1. A stirring blade 12 is integrally formed along the lower circumference of the stirring rod 11.

[0055] Specifically, since the transmission block 10 and the stirring plate 9 are integrally formed eccentrically, and the transmission block 10 is located inside the drive frame 4, rotating and slidingly engaging with the drive frame 4, as... Figure 4As shown, when the drive frame 4 reciprocates laterally, it can drive the stirring plate 9 to rotate inside the through hole through the transmission block 10, so that the stirring plate 9 drives the stirring rod 11 welded to it to rotate together, and then drives the stirring blade 12 integrally formed with it to rotate through the stirring rod 11, so as to stir and mix the components inside the processing chamber.

[0056] This invention utilizes seaweed-derived biochar as the core 13, matching its surface porous structure to the natural habitat of seaweed rhizosphere microorganisms, thereby efficiently loading probiotics. Simultaneously, the multiple slow-release structure formed by the hydrogel protective layer and the magnetic porous silica shell 15 reduces microbial loss and improves its environmental adaptability.

[0057] Using the biochar carrier in this embodiment as the experimental group and existing agricultural waste biochar as the control group, the results are shown in the table below:

[0058] Table 1. Experimental Control Table

[0059] As shown in the table, the net photosynthetic rate, transpiration rate and total nitrogen content in the sediment of the experimental group were all higher than those of the control group, indicating that the experimental group had a better overall regulatory effect on the microbial community of seagrass beds than existing agricultural waste biochar.

[0060] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A biochar carrier for modulating microbial communities in a seagrass bed, characterized in that, The core (13) is sequentially coated with an intermediate layer (14) and a shell (15) from the inside to the outside; The core (13) comprises a seagrass plant source biochar prepared by pyrolysis of seagrass raw materials, and is used for loading probiotics; The intermediate layer (14) comprises a hydrogel protective layer formed by cross-linking sodium alginate and chitosan with calcium ions, and is used for protecting probiotics and providing a slow-release environment; The shell (15) comprises a magnetic porous silica shell (15) with nano Fe3O4 particles and seagrass rhizosphere signal molecules added inside, and is used for providing physical protection for the biochar carrier.

2. The biochar carrier for modulating microbial communities of seagrass beds of claim 1, wherein, The manufacturing method comprises the following steps: Step one, raw material pretreatment: the discarded seagrass salvaged from the degraded seagrass bed is used as raw material, which is washed with distilled water and then pyrolyzed. After pyrolysis is completed, the raw material is placed in a preparation device, and the raw material is crushed and sieved by a crushing assembly in the preparation device to obtain biochar particles; Step two, intermediate layer (14) coating: sodium alginate and chitosan are placed in the preparation device, and a sodium alginate-chitosan mixed solution is configured by a stirring assembly in the preparation device. The biochar particles are added to the sodium alginate-chitosan mixed solution, and then calcium chloride solution is added for cross-linking and solidification to form a hydrogel layer, which is used as the intermediate layer (14) to coat the biochar particles, and wet particles are obtained; Step three, shell (15) preparation: the wet particles are dried to obtain gel particles. Meanwhile, tetraethyl orthosilicate and anhydrous ethanol are mixed, and nano Fe3O4 particles and seagrass rhizosphere signal molecules are added to obtain a mixed solution. Dilute ammonia water is added to the mixed solution and continuously stirred until the mixed solution is stirred into sol. Then, the gel particles are immersed in the sol for coating. After the coating is completed, the particles are taken out and dried to make the tetraethyl orthosilicate completely hydrolyze and condense to form a porous silica shell (15); Step four, probiotic loading: the probiotic bacterial solution is mixed with the nutrient solution, and the probiotic bacterial solution is adsorbed into the pores of the biochar core (13) to realize the loading of probiotics.

3. The biochar carrier for modulating microbial communities of seagrass beds of claim 2, wherein, In step one, the pyrolysis temperature is 400-600°C during pyrolysis.

4. The biochar carrier for modulating microbial communities of seagrass beds of claim 3, wherein, In step one, the particle size of the raw material is 0.25-2 mm during sieving.

5. The biochar carrier for modulating microbial communities of seagrass beds of claim 4, wherein, In step three, the concentration of dilute ammonia water is 2-4%.

6. The biochar carrier for modulating microbial communities of seagrass beds of claim 5, wherein, In step four, the probiotics are selected from one or more of nitrogen-fixing bacteria, phosphorus-dissolving bacteria, and pollutant-degrading bacteria; and the nutrient solution is selected from one of phosphate buffer and Tris-HCl buffer.

7. The biochar carrier for modulating microbial communities of seagrass beds of claim 6, wherein, In step four, the vacuum impregnation method is used to load the probiotics.

8. A device for the preparation of a biochar carrier for regulating the microbial community of a seagrass bed, suitable for the biochar carrier for regulating the microbial community of a seagrass bed according to any one of claims 1 to 7, characterized in that, The utility model relates to a kind of raw material processing device, including controller and shell (1), shell (1) top is opened with feed inlet, shell (1) side wall is opened with feeding port and discharge port, discharge port place detachably connected with rubber plug (2), shell (1) inner side wall is fixedly connected with baffle (3), baffle (3) is sequentially separated into drive cavity and processing cavity from top to bottom in shell (1) inside, processing cavity inner bottom wall is fixedly connected with telescopic piece, controller is used to control the opening and closing of telescopic piece, telescopic piece output shaft is coaxially fixedly connected with driving frame (4), driving frame (4) is provided with the broken component for breaking raw material at the end away from telescopic piece output shaft; Baffle (3) is opened with through-hole, and stirring assembly for stirring mixed solution is arranged in through-hole.

9. The device for preparing a biochar carrier for modulating microbial communities of a seagrass bed according to claim 8, characterized in that, Broken component includes broken box (6) fixedly connected to the top of baffle (3), broken box (6) top is opened with discharge port, discharge port is located just below feed inlet, broken box (6) inner side wall is transversely slidably connected with broken plate (7), driving frame (4) is fixedly connected with broken plate (7) at the end away from telescopic piece output shaft and extending to the inside of broken box (6) through broken box (6) side wall, broken box (6) bottom is fixedly connected with screen (8), baffle (3) is opened with drop port, and broken box (6) is communicated with processing cavity through screen (8) and drop port;Broken plate (7) bottom is fixedly connected with dredging brush.

10. The device for preparing a biochar carrier for modulating microbial communities of a seagrass bed according to claim 9, characterized in that, Stirring assembly includes stirring disc (9) rotationally fitted in through-hole, stirring disc (9) top eccentrically fixedly connected with transmission block (10), transmission block (10) is located in driving frame (4) and rotationally and slidably fitted with driving frame (4), stirring disc (9) bottom is fixedly connected with stirring rod (11), stirring rod (11) end away from stirring disc (9) is rotationally fitted with shell (1) inner bottom wall, stirring rod (11) is fixedly connected with stirring blade (12) along its lower part periphery.

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