A biomimetic structure preparation system based on microbially induced calcium carbonate precipitation

Abstract

The present invention discloses a bionic structure preparation system based on microbial-induced calcium carbonate precipitation, which includes a liquid storage tank, two mixing tanks, and two storage tanks. A feed pipe is provided on the side wall of the aggregate bin, an exhaust pipe is provided inside the aggregate bin, and a linkage pipe is provided on the outer wall of the bottom of the aggregate bin; the stirring mechanism includes a support platform and a discharge pipe. A plurality of second magnetic plates are provided on the outer wall of the rotating column along its circumferential direction. The upper end of the discharge pipe is connected to the lower end of the linkage pipe. A plurality of discharge holes are opened on the outer wall of the discharge pipe. The lower end of the discharge pipe is closed and a plurality of stirring blades are provided on its outer wall. A first magnetic plate is provided on each stirring blade; the two storage tanks are placed on the preparation platform, and a printing nozzle is provided on the robotic arm. The present invention utilizes the principle of local hydrodynamic condition regulation and gel-enhanced ion adsorption of the bionic structure to specifically regulate the range of bacterial retention and the precipitation growth rate, and further specifically block the preferential seepage paths formed during the plugging process of porous media.

Description

Technical Field

[0001] The present invention relates to the technical field of anti-seepage and plugging of geotechnical engineering by bionic structures, and particularly to a preparation system of bionic structures based on microbial-induced calcium carbonate precipitation. Background Art

[0002] Bionic structures are composite materials with specific properties synthesized by bionic synthesis strategies inspired by organisms and natural bionic principles. This is also a rapidly emerging and developing field in recent years and has become one of the forefront hotspots in the interdisciplinary research of chemistry, life materials, physics and other disciplines.

[0003] Microbial-induced calcium carbonate precipitation (MICP) technology can be applied to the field of anti-seepage and plugging of geotechnical engineering. Currently, from a large number of tests on MICP technology for solidifying sand columns, it is found that this technology can block most of the voids in porous media. However, new seepage channels may be formed between the unblocked voids. Once the new seepage channels are connected and expanded, there will be a potential risk of developing into dominant seepage paths and even regional leakage disasters. At present, there is no MICP strengthening method that uses bionic structures to regulate the local fluid flow conditions in geotechnical media and then promotes the effective retention of bacteria, so it is impossible to induce effective calcium carbonate precipitation, difficult to achieve efficient plugging of seepage channels, and unable to effectively improve the anti-seepage and plugging effect of MICP technology in geotechnical engineering. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation system of bionic structures based on microbial-induced calcium carbonate precipitation, so as to batch-prepare bionic structures for regulating the local fluid flow state of voids in geotechnical media and then specifically plugging the voids of the media, in order to achieve the purpose of improving the overall anti-seepage and plugging effect of MICP technology in geotechnical engineering.

[0005] The present invention is realized through the following technical solutions:

[0006] A preparation system of bionic structures based on microbial-induced calcium carbonate precipitation includes a liquid storage tank, two mixing tanks and two storage tanks. The liquid storage tank is connected to the mixing tank through a liquid supply pipeline, and the mixing tank is connected to the storage tank through a connecting pipe. A feeding mechanism is provided on each mixing tank. The feeding mechanism includes a vertically placed aggregate bin. An inlet pipe communicating with the inside is provided on the side wall of the aggregate bin. An exhaust pipe with an inner diameter decreasing downward along the vertical direction is provided in the aggregate bin. The upper end of the exhaust pipe penetrates through the top of the aggregate bin and is connected to a horizontally placed guiding pipe. A blower is provided on the side wall of the aggregate bin. An outer exhaust fan blade is provided at the output end of the blower, and the outer exhaust fan blade is placed in the guiding pipe. A linkage pipe communicating with the inside is provided on the outer wall of the bottom of the aggregate bin, and there is a spacing between the upper end surface of the linkage pipe and the lower end surface of the exhaust pipe;

[0007] It further includes a stirring mechanism for solid-liquid mixing in the mixing tank. The stirring mechanism includes a support platform and a discharge pipe. The mixing tank is placed on the support platform. A driving motor is provided inside the support platform. A rotating column is connected to the output end of the driving motor. A plurality of second magnetic plates are provided on the outer wall of the rotating column along its circumferential direction. The upper end of the discharge pipe is connected to the lower end of the linkage pipe. A plurality of discharge holes are formed on the outer wall of the discharge pipe. The lower end of the discharge pipe is closed and a plurality of stirring blades are provided on its outer wall. And each stirring blade is provided with a first magnetic plate that cooperates with the second magnetic plate. After the driving motor is started, it drives the second magnetic plates to rotate, and at the same time the first magnetic plates rotate synchronously therewith;

[0008] Two storage tanks are placed on the preparation platform, and a printing table and a robotic arm are provided on the preparation platform. A printing nozzle connected to the two storage tanks through a connecting hose is provided on the robotic arm.

[0009] In the existing microbial-induced calcium carbonate precipitation (MICP) technology, when used for seepage prevention and plugging in geotechnical engineering, some voids may not be blocked, and new seepage channels may be formed between the missed voids, greatly reducing the plugging effect. The reason is that the residence time of bacteria passing through the voids is relatively short, and the production rate of calcium carbonate precipitation cannot meet the requirements for effective plugging in this area; in view of the above defects, the inventor designed and developed a bionic structure preparation system specifically for seepage prevention and plugging in geotechnical engineering. After sequentially completing various processes such as mixing and stirring of multiple stock solutions, the corresponding plugging composite material, that is, the bionic structure, is prepared through the printing nozzle. And when plugging and preventing seepage, by using the principle of local hydrodynamic condition regulation and gel-enhanced ion adsorption of the bionic structure, the retention range of bacteria and the precipitation growth rate are targeted regulated, and the dominant seepage paths formed during the plugging process of porous media are plugged in a targeted manner.

[0010] The specific preparation process is as follows:

[0011] The deionized water in the liquid storage tank is respectively pumped into the two mixing tanks through the liquid supply pipelines, and a quantitative amount of powdered polyvinyl alcohol and sodium alginate are respectively put into the two mixing tanks through two feeding components. After being fully stirred by the stirring mechanism, the dissolution is completed. Then calcium chloride and urea are injected into the mixing tank filled with polyvinyl alcohol to form a first mixed solution, and a bacterial solution is injected into the mixing tank filled with sodium alginate to form a second mixed solution. And the first mixed solution and the second mixed solution are respectively injected into the two storage tanks through the connecting pipes. Finally, the first mixed solution and the second mixed solution are converged by the printing nozzle and formed on the printing table to obtain the preparation target, that is, the gel-like bionic structure.

[0012] It should be noted that when injecting powder, bacterial liquid, or a mixture of calcium chloride and urea into the mixing tank respectively, the mixing of solid phase and liquid phase, and liquid phase and liquid phase is involved. The injection amount of the powder, the injection amount of the liquid phase, and the mixing uniformity between the phases all have a significant impact on the later printed bionic structure. Therefore, when injecting the powder, this technical solution uses a special feeding mechanism to quantitatively put it. That is, the powder-like polyvinyl alcohol or sodium alginate is put into the mixing tank by means of air separation and swirling. The specific working principle is as follows: When the fan starts, while driving the outer exhaust fan blades to rotate, the air in the aggregate bin is discharged outward. A certain amount of polyvinyl alcohol powder enters the interior of the aggregate bin together with part of the air through the feed pipe. After moving a certain distance around the outer wall of the exhaust air pipe, a swirl is formed on the inner wall of the aggregate bin with a gradually decreasing inner diameter. The polyvinyl alcohol particles move downward to the bottom of the aggregate bin under the action of gravity, and the air mixed with the polyvinyl alcohol particles enters along the bottom of the exhaust air pipe and is discharged outward through the guiding pipe. The polyvinyl alcohol particles continuously accumulating at the bottom of the aggregate bin pass through the linkage pipe and the discharge pipe successively, and then are discharged into the mixing tank through the discharge hole. The discharge pipe and the stirring blade rotate due to the interaction between the first magnetic plate and the second magnetic plate. That is, when the polyvinyl alcohol particles enter the interior of the discharge pipe, they are preliminarily mixed with the deionized water flowing back in. The finally prepared high-concentration polyvinyl alcohol liquid will be radiated and diffused to the deionized water gathered in the mixing tank in a rotating jet manner. After injecting the corresponding proportion of calcium chloride and urea solution into the mixing tank, it is fully stirred by the stirring blade to prepare the first mixed solution. The powder-like polyvinyl alcohol or sodium alginate is fed by swirling, which can minimize the adhesion amount in the aggregate bin to ensure that the prepared first mixed solution meets the preparation requirements and prevent dust generation during traditional powder feeding.

[0013] Furthermore, when stirring in the mixing tank, magnetic stirring is adopted. That is, the driving motor arranged in the support platform drives the rotation of multiple second magnetic plates on the rotating column, and the first magnetic plate at the bottom of the stirring blade is correspondingly arranged with the second magnetic plate. Using the principle that like magnetic poles attract each other, the first magnetic plate will also rotate with the rotation of the first magnetic plate, thereby realizing the full mixing of the high-concentration polyvinyl alcohol liquid and the deionized water. Finally, after injecting a specific proportion of calcium chloride and urea solution into the mixing tank, the stirring blade continues to rotate and stir. After obtaining the first mixed solution that meets the conditions, it is pumped to a storage tank through the connecting pipe. Similarly, the mixing method of the powder-like sodium alginate and the bacterial liquid is similar to the above description. After finally obtaining the second mixed solution that meets the conditions, it is pumped to another storage tank through the connecting pipe. Finally, the robotic arm, the connecting hose, and the printing nozzle cooperate with each other to complete the preparation of the gel-like bionic structure on the printing table.

[0014] At the lower end face of the aggregate bin, there are a straight section and a narrowing section that are interconnected. The lower end of the narrowing section is closed and its inner diameter decreases sequentially from top to bottom. The upper end of the linkage pipe is connected to the closed end of the narrowing section. At the bottom of the exhaust pipe, there is a disc with a plurality of ventilation holes. On the upper surface of the middle part of the disc, a rotating bearing is fixed. The upper end of the follower rod passes through the disc movably and extends upward. The outer wall of the follower rod is connected to the inner ring of the rotating bearing, and a follower fan blade is provided on the extended section. Along the axial direction of the follower rod, a spiral blade is provided on its outer wall. Further, when preparing the mixed solution in the mixing tank, it is necessary to ensure that the concentration of the mixed solution meets the requirements. Since a part of the air will be carried in during the swirling feeding, it is easy for particles with ultra-small sizes to suspend at the bottom of the aggregate bin and cannot enter the linkage pipe in time. For this, in this technical solution, a straight section and a narrowing section that are interconnected are provided at the lower end face of the aggregate bin, and a follower rod and a follower fan blade are additionally provided. Among them, the lower end face of the follower rod is flush with the lower end face of the straight section, and the correspondingly arranged spiral blade is located in the straight section. The follower fan blade rotatably arranged in the exhaust air pipe will rotate under the traction of the external exhaust air flow (the air flow generated when the external exhaust fan blade rotates). While accelerating the speed of the external exhaust air, it drives the spiral blade to rotate. Except for its own gravity, the powder moving down along the inner wall of the straight section can also be guided and blocked to a certain extent by the spiral blade, accelerating the downward movement of the powder and reducing the probability of particles with ultra-small sizes suspending in the straight section.

[0015] At least two clamping blocks are provided on the inner wall of the narrowing section. An annular end plate is provided on the outer edge of the upper end face of the linkage pipe, and the outer circumferential wall of the end plate is connected to the inner wall of the narrowing section through a flexible sealing cover. Along the axial direction of the linkage pipe, a sliding groove that is slidably matched with the clamping block is opened on the outer wall of its upper end. An annular guiding groove is opened on the upper end face of the end plate. The inner diameter of the guiding groove decreases sequentially from top to bottom. The end face of the large diameter end of the guiding groove is flush with the upper surface of the end plate, and the end face of the small diameter end of the guiding groove is flush with the upper end face of the linkage pipe.

[0016] A magnetic isolation cover is provided in the middle of the upper end face of the rotating column. An electromagnet is provided inside the magnetic isolation cover. A permanent magnet that cooperates with the electromagnet is provided on the lower end face of the discharge pipe. A magnetic isolation corrugated pipe is sleeved on the outer wall of the permanent magnet, and the two ends of the magnetic isolation corrugated pipe are respectively connected to the inner wall of the bottom of the mixing tank and the lower end face of the discharge pipe.

[0017] In the initial state, the lower surface of the end head plate contacts the upper surface of the clamping block, and there is a gap between the lower end of the sliding groove and the lower surface of the clamping block. Further, when stirring the liquid in the mixing tank, this technical solution adopts a combination of fixed-point stirring and transposition stirring; during fixed-point stirring, the first magnetic plate and the second magnetic plate cooperate with each other to make the stirring blade rotate in place. When realizing transposition stirring, the linkage pipe and the reduced section are set to be movably connected, and relative rotation can be achieved between the linkage pipe and the discharge pipe. A magnetic isolation cover is arranged in the middle of the rotating column, an electromagnet is arranged in the isolation cover, and a magnetic isolation bellows is arranged at the bottom of the discharge pipe. A permanent magnet matched with the electromagnet is arranged in the magnetic isolation bellows. That is, by changing the current intensity and current direction of the electromagnet, mutual attraction or mutual repulsion of the electromagnets can be achieved. The arranged magnetic isolation cover and magnetic isolation bellows can reduce the mutual interference between the electromagnet and the second magnetic plate, and between the permanent magnet and the first magnetic plate; by using the mutual repulsion between the electromagnet and the permanent magnet, the linkage pipe, the discharge pipe and multiple stirring blades can all move up a certain distance in the vertical direction, that is, appropriately change the stirring center in the mixing tank, and at the same time, the high-concentration liquid discharged from the discharge hole can be sprayed at different vertical heights in the mixing tank to improve the mixing and stirring efficiency. Among them, the linkage pipe and the discharge pipe are connected through a connecting bearing, and a movable seal is arranged at the connection between the two. That is, when the discharge pipe rotates normally, the linkage pipe remains stationary, and when the electromagnet and the permanent magnet cooperate, the linkage pipe can perform a linear motion along its axis. That is, the end head plate located on the upper end surface of the linkage pipe will drive the flexible seal cover to move up and down in the reduced section, and at the same time, the clamping block and the sliding groove cooperate with each other to limit the linkage pipe in the circumferential direction; it should be particularly noted that the transposition stirring does not only switch the horizontal height of the stirring blade once, but switches regularly multiple times, and when the distance between the stirring blade and the bottom of the tank reaches the limit value, the interaction between the first magnetic plate and the second magnetic plate can still play a role, the difference being that the rotation speed of the stirring blade drops to the lowest.

[0018] A connecting ring is provided inside the mixing tank, and the outer ends of multiple stirring blades are connected to the inner circumferential wall of the connecting ring; further included are multiple spiral dispersion blades, with the upper end of each dispersion blade connected to the outer wall of the discharge pipe, and the lower end of the dispersion blade connected to the upper end surface of the connecting ring. Further, when the powder is fed, some air will be brought in. Even after the external discharge treatment through the exhaust pipe, a small amount of residual air will still enter the solution through the linkage pipe, the discharge pipe, and the discharge hole, increasing the amount of bubbles in the liquid in the mixing tank and directly affecting the concentration value of the first mixed liquid. In response to this, in this technical solution, the outer ends of multiple stirring blades are fixed through the connecting ring, and multiple spiral dispersion blades are provided on the connecting ring. When the dispersion blades rotate and lift together with the discharge pipe, they can enhance the stirring effect and at the same time shear the bubbles generated in the middle of the mixing tank, accelerating their breaking speed. It should be noted that during the entire preparation process of the mixed liquid, the liquid level in the mixing tank never reaches the highest liquid level point of the mixing tank (i.e., the inner wall at the top of the mixing tank).

[0019] An exhaust pipe communicating with the inside is also provided at the top of the mixing tank. Preferably, by opening and closing the exhaust pipe, the gas at the top inside the mixing tank can be regularly discharged externally to ensure an atmospheric pressure environment inside the mixing tank.

[0020] A constant temperature heating sheet is wrapped around the outer wall of each mixing tank. Preferably, the constant temperature heating sheet can heat the mixed liquid during the stirring process to a constant temperature to accelerate the preparation progress.

[0021] It further includes a cooling table. There are two cooling tanks corresponding to the two mixing tanks respectively on the cooling table, and the mixing tank is communicated with the cooling tank through a liquid delivery pipeline. The cooling tank is communicated with the storage tank through a liquid inlet pipeline; stirrers are provided in both cooling tanks; a rectangular groove is opened on the lower surface of the cooling table, and multiple heat dissipation fins are arranged side by side in the rectangular groove. Further, after the solute particles such as sodium alginate or polyvinyl alcohol are fully dissolved in the mixing tank, they still have a certain temperature and are not convenient to directly inject the bacterial liquid into them. It is necessary to wait until they are cooled to 15 to 30 °C before proceeding. The natural cooling time is relatively long. In response to this, this technical solution sets up a cooling table and two cooling tanks, and transfers the injection link of the bacterial liquid and the solidifying liquid prepared with calcium chloride and urea to the cooling tank. That is, the solution in the mixing tank is transferred to the cooling pipe through the liquid delivery pipeline, and the cooperation of the heat dissipation fins at the bottom of the cooling table and the fan is used to shorten the time for the solution to cool to the range of 15 to 30 °C. Moreover, the stirrers in the cooling tanks can drive the bacterial liquid and the solidifying liquid to be fully mixed with their respective corresponding solutions, that is, while accelerating the cooling, ensuring that the mixed liquid pumped out from the cooling tank meets the corresponding concentration requirements.

[0022] It also includes a mixing cavity. A feeding pipe is provided on each storage tank, and a peristaltic pump is provided on the feeding pipe. The two feeding pipes are respectively communicated with two feeding ports of the mixing cavity, and the discharging port of the mixing cavity is communicated with a connecting hose. Preferably, on the preparation platform, the robotic arm drives the printing nozzle to move autonomously, and different stock solutions in the two storage tanks are converged and directly sprayed on the printing table. The mixing cavity is arranged in this technical solution, which can pre-mix the two stock solutions and then transmit them to the printing nozzle through the connecting hose, that is, shorten the forming time of the two stock solutions on the printing table.

[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0024] 1. After sequentially completing processes such as mixing and stirring of multiple stock solutions, the present invention prepares the corresponding plugging composite material, that is, the bionic structure, through the printing nozzle. And when plugging and preventing seepage, by using the principle of local hydrodynamic condition regulation and gel-enhanced ion adsorption of the bionic structure, the range of bacterial retention and the precipitation growth rate are targeted regulated, and further targeted plugging is carried out on the dominant seepage path formed during the plugging process of the porous medium.

[0025] 2. By using the mutual repulsion between the electromagnet and the permanent magnet, the linkage pipe, the discharge pipe, and multiple stirring blades can all move up a certain distance in the vertical direction, that is, appropriately change the stirring center in the mixing tank, and at the same time enable the high-concentration liquid discharged from the discharge hole to be sprayed at different vertical heights in the mixing tank to improve the mixing and stirring efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, form a part of this application, and do not constitute a limitation to the embodiments of the present invention. In the drawings:

[0027] Figure 1 is a schematic structural diagram of the present invention;

[0028] Figure 2 is a schematic diagram of the cooperation between the feeding mechanism and the stirring mechanism;

[0029] Figure 3 is Figure 2 an enlarged view of part A in

[0030] Figure 4 is a bottom view of the connecting ring.

[0031] The components represented by the reference numerals are as follows: 1 - liquid storage tank, 2 - liquid supply pipeline, 3 - feeding mechanism, 31 - fan, 32 - feed pipe, 33 - exhaust pipe, 34 - aggregate bin, 35 - follower fan blade, 36 - follower rod, 37 - spiral blade, 38 - tightening section, 39 - linkage pipe, 310 - chute, 311 - clamping block, 312 - flexible seal cover, 313 - end plate, 314 - outer exhaust fan blade, 4 - mixing tank, 41 - exhaust pipe, 5 - stirring mechanism, 51 - discharge pipe, 52 - rotating column, 53 - dispersing blade, 54 - second magnetic plate, 55 - stirring blade, 56 - connecting ring, 57 - first magnetic plate, 58 - driving motor, 59 - discharge hole, 510 - permanent magnet, 511 - magnetic isolation corrugated pipe, 512 - electromagnet, 6 - preparation platform, 61 - storage tank, 62 - printing nozzle, 63 - printing table, 64 - robotic arm, 7 - cooling table, 8 - liquid supply pipeline, 9 - cooling tank, 10 - liquid inlet pipeline. Detailed implementation mode

[0032] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the embodiments and the drawings. The illustrative embodiments and descriptions thereof of the present invention are only used to explain the present invention and are not intended to limit the present invention. It should be noted that the present invention has been in the actual R & D and use stage.

[0033] Embodiment 1

[0034] As Figures 1 to 4 shown, this embodiment includes a liquid storage tank 1, two mixing tanks 4 and two storage tanks 61. The liquid storage tank 1 is connected to the mixing tank 4 through a liquid supply pipeline. The mixing tank 4 is connected to the storage tank 61 through a connecting pipe. A feeding mechanism 3 is provided on each mixing tank 4. The feeding mechanism 3 includes a vertically placed aggregate bin 34. A feed pipe 32 communicating with its interior is provided on the side wall of the aggregate bin 34. An exhaust pipe 33 with an inner diameter decreasing downward along the vertical direction is provided in the aggregate bin 34. The upper end of the exhaust pipe 33 penetrates through the top of the aggregate bin 34 and is connected to a horizontally placed guiding pipe. A fan 31 is provided on the side wall of the aggregate bin 34. An outer exhaust fan blade 314 is provided at the output end of the fan 31, and the outer exhaust fan blade 314 is placed in the guiding pipe. A linkage pipe 39 communicating with its interior is provided on the outer wall of the bottom of the aggregate bin 34, and there is a gap between the upper end surface of the linkage pipe 39 and the lower end surface of the exhaust pipe 33;

[0035] It further includes a stirring mechanism 5 for solid-liquid mixing in the mixing tank 4. The stirring mechanism 5 includes a support platform and a discharge pipe 51. The mixing tank 4 is placed on the support platform. A driving motor 58 is provided inside the support platform. A rotating column 52 is connected to the output end of the driving motor 58. A plurality of second magnetic plates 54 are provided on the outer wall of the rotating column 52 along its circumferential direction. The upper end of the discharge pipe 51 is connected to the lower end of the linkage pipe 39. A plurality of discharge holes 59 are formed on the outer wall of the discharge pipe 51. The lower end of the discharge pipe 51 is closed and a plurality of stirring blades 55 are provided on its outer wall. And a first magnetic plate 57 that cooperates with the second magnetic plate 54 is provided on each stirring blade 55. After the driving motor 58 is started, it drives the second magnetic plate 54 to rotate, and at the same time the first magnetic plate 57 rotates synchronously therewith;

[0036] Two storage tanks 61 are placed on the preparation platform 6, and a printing table 63 and a robotic arm 64 are provided on the preparation platform 6. A printing nozzle 62 that is communicated with the two storage tanks 61 through a connecting hose is provided on the robotic arm 64.

[0037] The specific preparation process is as follows:

[0038] The deionized water in the liquid storage tank 1 is respectively pumped into the two mixing tanks 4 through the liquid supply pipelines. And a quantitative amount of powdered polyvinyl alcohol and sodium alginate are respectively put into the two mixing tanks 4 through the two feeding components. After being fully stirred by the stirring mechanism 5, the dissolution is completed. Then calcium chloride and urea are injected into the mixing tank 4 filled with polyvinyl alcohol to form a first mixed liquid, and a bacterial solution is injected into the mixing tank 4 filled with sodium alginate to form a second mixed liquid. And the first mixed liquid and the second mixed liquid are respectively injected into the two storage tanks 61 through the connecting pipes. Finally, the first mixed liquid and the second mixed liquid are converged by the printing nozzle 62 and formed on the printing table 63 to obtain the preparation target, that is, the gel-like bionic structure.

[0039] It should be noted that when injecting powder, bacterial liquid, or a mixture of calcium chloride and urea into the mixing tank 4 respectively, it involves the mixing of solid phase and liquid phase, and liquid phase and liquid phase. The injection amount of the powder, the injection amount of the liquid phase, and the mixing uniformity between the phases all have a significant impact on the later printed bionic structure. Therefore, when injecting the powder, in this embodiment, a special feeding mechanism 3 is used for quantitative feeding, that is, the powder-like polyvinyl alcohol or sodium alginate is fed into the mixing tank 4 by means of air separation and swirling. The specific working principle is as follows: When the fan 31 is started, while driving the outer exhaust fan blade 314 to rotate, the air in the aggregate bin 34 is discharged outward. A certain amount of polyvinyl alcohol powder enters the interior of the aggregate bin 34 together with the feed pipe 32 and part of the air. After moving a certain distance around the outer wall of the exhaust air pipe 33, a swirl is formed on the inner wall of the aggregate bin 34 with a gradually decreasing inner diameter. The polyvinyl alcohol particles move downward to the bottom of the aggregate bin 34 under the action of gravity, and the air mixed with the polyvinyl alcohol particles enters along the bottom of the exhaust air pipe 33 and is discharged outward through the guiding pipe. The polyvinyl alcohol particles continuously accumulating at the bottom of the aggregate bin 34 pass through the linkage pipe 39 and the discharge pipe 51 in sequence, and then are discharged into the mixing tank 4 through the discharge hole 59. The discharge pipe 51 and the stirring blade 55 rotate due to the interaction between the first magnetic plate 57 and the second magnetic plate 54, that is, when the polyvinyl alcohol particles enter the interior of the discharge pipe 51, they are preliminarily mixed with the deionized water flowing back. The finally prepared high-concentration polyvinyl alcohol liquid will be radiated and diffused in a rotating jet manner to the deionized water gathered in the mixing tank 4. After injecting the calcium chloride and urea solution with a corresponding ratio into the mixing tank 4, the first mixed liquid is prepared after sufficient stirring by the stirring blade 55. The powder-like polyvinyl alcohol or sodium alginate is fed by swirling, which can minimize the adhesion amount in the aggregate bin 34 to ensure that the prepared first mixed liquid meets the preparation requirements, and at the same time prevent dust generation during traditional powder feeding.

[0040] When stirring in the mixing tank 4, magnetic stirring is adopted. That is, the driving motor 58 arranged in the support platform drives the rotation of multiple second magnetic plates 54 on the rotating column 52, and the first magnetic plate 57 at the bottom of the stirring blade 55 is correspondingly arranged with the second magnetic plate 54. Using the principle that like magnetic poles attract each other, the first magnetic plate 57 will also rotate as the first magnetic plate 57 rotates, thereby realizing the full mixing of the high-concentration polyvinyl alcohol liquid and deionized water. Finally, after injecting a specific proportion of calcium chloride and urea solution into the mixing tank 4, the stirring blade 55 continues to rotate and stir. After obtaining the first mixed liquid that meets the conditions, it is pumped into a storage tank 61 through the connecting pipe. Similarly, the mixing method of the powder-like sodium alginate and the bacterial liquid is similar to the above description. After finally obtaining the second mixed liquid that meets the conditions, it is pumped into another storage tank 61 through the connecting pipe. Finally, the robotic arm 64, the connecting hose, and the printing nozzle 62 cooperate with each other to complete the preparation of the gel-like bionic structure on the printing table 63.

[0041] Among them, a straight section and a reducing section that communicate with each other are provided on the lower end face of the aggregate bin 34. The lower end of the reducing section is closed and its inner diameter decreases successively from top to bottom. The upper end of the linkage pipe 39 communicates with the closed end of the reducing section. A disc is provided at the bottom of the exhaust pipe 33, and a plurality of ventilation holes are opened on the disc. A rotating bearing is fixed on the upper surface of the middle part of the disc. The upper end of the follower rod 36 movably penetrates through the disc and extends upward. The outer wall of the follower rod 36 is connected to the inner ring of the rotating bearing, and a follower fan blade 35 is provided on the extended section thereof. A spiral blade 37 is provided on the outer wall of the follower rod 36 along its axial direction. When preparing the mixed solution in the mixing tank 4, it is necessary to ensure that the concentration of the mixed solution meets the requirements. Since part of the air will be brought in during the swirling feeding, particles with ultra-small sizes are likely to be suspended at the bottom of the aggregate bin 34 and cannot enter the linkage pipe 39 in time. For this reason, in this embodiment, a straight section and a reducing section that communicate with each other are provided on the lower end face of the aggregate bin 34, and a follower rod 36 and a follower fan blade 35 are additionally provided. The lower end face of the follower rod 36 is flush with the lower end face of the straight section. The correspondingly arranged spiral blade 37 is located in the straight section. The follower fan blade 35 rotatably arranged in the exhaust pipe 33 will rotate under the traction of the external exhaust air flow (the air flow generated when the external exhaust fan blade 314 rotates). While accelerating the external exhaust speed of the air, it drives the spiral blade 37 to rotate. Except for the influence of its own gravity, the powder moving down along the inner wall of the straight section can also be guided and blocked to a certain extent by the spiral blade 37, accelerating the downward movement of the powder and reducing the probability of ultra-small sized particles being suspended in the straight section.

[0042] Embodiment 2

[0043] As Figures 1 to 4 shown, on the basis of Embodiment 1, this embodiment further improves the feeding mechanism 3, that is, at least two clamping blocks 311 are provided on the inner wall of the reducing section. An annular end head plate 313 is provided on the outer edge of the upper end face of the linkage pipe, and the outer circumferential wall of the end head plate 313 is connected to the inner wall of the reducing section through a flexible sealing cover 312. A sliding groove 310 that slidably cooperates with the clamping block 311 is opened on the upper outer wall of the linkage pipe 39 along its axial direction. An annular guide groove is opened on the upper end face of the end head plate 313, and the inner diameter of the guide groove decreases successively from top to bottom. The end face of the large diameter end of the guide groove is flush with the upper surface of the end head plate 313, and the end face of the small diameter end of the guide groove is flush with the upper end face of the linkage pipe 39.

[0044] A magnetic isolation cover is provided in the middle of the upper end face of the rotating column 52, and an electromagnet 512 is provided inside the magnetic isolation cover. A permanent magnet 510 that cooperates with the electromagnet 512 is provided on the lower end face of the discharge pipe 51. A magnetic isolation bellows 511 is sleeved on the outer wall of the permanent magnet 510, and the two ends of the magnetic isolation bellows 511 are respectively connected to the inner wall of the bottom of the mixing tank 4 and the lower end face of the discharge pipe 51.

[0045] In the initial state, the lower surface of the end plate 313 contacts the upper surface of the clamping block 311, and there is a gap between the lower end of the sliding groove 310 and the lower surface of the clamping block 311.

[0046] When stirring the liquid in the mixing tank 4, the present technical solution adopts a combination of fixed-point stirring and transposition stirring; during fixed-point stirring, the first magnetic plate 57 and the second magnetic plate 54 cooperate with each other to make the stirring blade 55 rotate in place. When realizing transposition stirring, the linkage pipe 39 and the reduced section are arranged to be movably connected, and relative rotation can be achieved between the linkage pipe 39 and the discharge pipe 51. A magnetic isolation cover is arranged in the middle of the rotating column 52, an electromagnet 512 is arranged inside the isolation cover, a magnetic isolation bellows 511 is arranged at the bottom of the discharge pipe 51, and a permanent magnet 510 that cooperates with the electromagnet 512 is arranged inside the magnetic isolation bellows 511. That is, by changing the current intensity and direction of the electromagnet, mutual attraction or mutual repulsion of the electromagnets can be achieved, and the arranged magnetic isolation cover and magnetic isolation bellows 511 can reduce the mutual interference between the electromagnet 512 and the second magnetic plate 54, and between the permanent magnet 510 and the first magnetic plate 57; by using the mutual repulsion between the electromagnet and the permanent magnet 510, the linkage pipe 39, the discharge pipe 51 and multiple stirring blades 55 can all move up a certain distance in the vertical direction, that is, appropriately change the stirring center in the mixing tank 4, and at the same time, the high-concentration liquid discharged from the discharge hole 59 can be sprayed at different vertical heights in the mixing tank 4 to improve the mixing and stirring efficiency. Among them, the linkage pipe 39 and the discharge pipe 51 are connected through a connecting bearing, and a movable seal is arranged at the connection between the two. That is, when the discharge pipe 51 rotates normally, the linkage pipe 39 remains stationary, and when the electromagnet 512 cooperates with the permanent magnet 510, the linkage pipe 39 can perform a linear motion along its axis, that is, the end plate 313 located on the upper end surface of the linkage pipe 39 will drive the flexible seal cover 312 to move up and down in the reduced section, and at the same time, the clamping block 311 and the sliding groove 310 cooperate with each other to limit the linkage pipe 39 in the circumferential direction; it should be particularly pointed out that the transposition stirring does not only switch the horizontal height of the stirring blade 55 once, but switches regularly for multiple times, and when the distance between the stirring blade and the bottom of the tank reaches the limit value, the interaction between the first magnetic plate 57 and the second magnetic plate 54 can still play a role, and the difference is that the rotation speed of the stirring blade drops to the lowest.

[0047] Moreover, a connecting ring 56 is provided in the mixing tank 4, and the outer ends of a plurality of stirring blades 55 are connected to the inner circumferential wall of the connecting ring 56; further included are a plurality of spiral dispersion blades 53, the upper end of each dispersion blade 53 is connected to the outer wall of the discharge pipe 51, and the lower end of the dispersion blade 53 is connected to the upper end surface of the connecting ring 56. When the powder is fed, some air will be brought in. Even after the external discharge treatment through the exhaust pipe 33, there will still be a small amount of residual air entering the solution through the linkage pipe 39, the discharge pipe 51, and the discharge hole 59, increasing the amount of bubbles in the liquid in the mixing tank 4 and directly affecting the concentration value of the first mixed liquid. In response to this, in this technical solution, the outer ends of a plurality of stirring blades are fixed through the connecting ring 56, and a plurality of spiral dispersion blades 53 are provided on the connecting ring. When the dispersion blades 53 rotate and lift together with the discharge pipe 51, they can enhance the stirring effect and at the same time shear the bubbles generated in the middle of the mixing tank 4, accelerating their breaking speed. It should be noted that during the entire preparation process of the mixed liquid, the liquid level in the mixing tank 4 never reaches the highest liquid level point of the mixing tank 4 (i.e., the inner wall at the top of the mixing tank 4).

[0048] Preferably, by opening and closing the exhaust pipe 41, the gas at the top inside the mixing tank 4 can be regularly discharged to ensure the normal pressure environment inside the mixing tank 4.

[0049] Preferably, the constant temperature heating sheet can heat the mixed liquid during the stirring process to a constant temperature to accelerate the preparation progress.

[0050] Embodiment 3

[0051] As Figures 1 to 4 shown, on the basis of Embodiment 1, this embodiment further includes a cooling table 7. There are two cooling tanks 9 corresponding to the two mixing tanks 4 on the cooling table 7, and the mixing tank 4 is communicated with the cooling tank 9 through a liquid delivery pipeline 8. The cooling tank 9 is communicated with the storage tank 61 through a liquid inlet pipeline 10; there are stirrers in both cooling tanks 9; a rectangular groove is opened on the lower surface of the cooling table 7, and a plurality of heat dissipation fins are arranged side by side in the rectangular groove; further included is a mixing cavity. A feeding pipe is provided on each storage tank 61, a peristaltic pump is provided on the feeding pipe, and the two feeding pipes are respectively communicated with the two feeding ports of the mixing cavity. The discharge port of the mixing cavity is communicated with a connecting hose.

[0052] After the solute particles such as sodium alginate or polyvinyl alcohol are fully dissolved in the mixing tank 4, they still have a certain temperature, which is not convenient for directly injecting the bacterial liquid into them. It is necessary to wait until they are cooled to 15 to 30 °C before proceeding. The natural cooling time is relatively long. In this regard, this technical solution sets up a cooling table 7 and two cooling tanks 9, and transfers the injection links of the bacterial liquid and the solidifying liquid prepared from calcium chloride and urea to the cooling tank 9. That is, the solution in the mixing tank 4 is transferred to the cooling pipe through the liquid delivery pipeline 8, and the heat dissipation fins at the bottom of the cooling table 7 and the fan 31 are used in cooperation to shorten the time for the solution to cool to the range of 15 to 30 °C. Moreover, the stirrer in the cooling tank 9 can drive the bacterial liquid and the solidifying liquid to be fully mixed with their respective corresponding solutions respectively. That is, while accelerating the cooling, it is ensured that the mixed liquid pumped out of the cooling tank 9 meets the corresponding concentration requirements.

[0053] Preferably, on the preparation platform 6, the robotic arm 64 drives the printing nozzle 62 to move autonomously, and converges the different stock solutions in the two storage tanks 61 and directly sprays them onto the printing table 63. This technical solution sets up a mixing cavity, which can pre-mix the two stock solutions and then transmit them to the printing nozzle 62 through the connecting hose, that is, shortening the forming time of the two stock solutions on the printing table 63.

[0054] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A bionic structure preparation system based on microbial-induced calcium carbonate precipitation, comprising a liquid storage tank (1), two mixing tanks (4), and two storage tanks (61). The liquid storage tank (1) is connected to the mixing tank (4) through a liquid supply pipeline, and the mixing tank (4) is connected to the storage tank (61) through a connecting pipe. It is characterized in that: A feeding mechanism (3) is provided on each mixing tank (4). The feeding mechanism (3) includes a vertically placed aggregate bin (34). An inlet pipe (32) communicating with its interior is provided on the side wall of the aggregate bin (34). An exhaust pipe (33) with an inner diameter decreasing downward along the vertical direction is provided in the aggregate bin (34). The upper end of the exhaust pipe (33) penetrates through the top of the aggregate bin (34) and is connected to a horizontally placed guiding pipe. A blower (31) is provided on the side wall of the aggregate bin (34). An outer exhaust fan blade (314) is provided at the output end of the blower (31), and the outer exhaust fan blade (314) is placed in the guiding pipe. A linkage pipe (39) communicating with its interior is provided on the outer wall of the bottom of the aggregate bin (34), and there is a gap between the upper end surface of the linkage pipe (39) and the lower end surface of the exhaust pipe (33). It further includes a stirring mechanism (5) for solid-liquid mixing in the mixing tank (4). The stirring mechanism (5) includes a support platform and a discharge pipe (51). The mixing tank (4) is placed on the support platform. A driving motor (58) is provided in the support platform. A rotating column (52) is connected to the output end of the driving motor (58). A plurality of second magnetic plates (54) are provided on the outer wall of the rotating column (52) along its circumferential direction. The upper end of the discharge pipe (51) is connected to the lower end of the linkage pipe (39). A plurality of discharge holes (59) are formed on the outer wall of the discharge pipe (51). The lower end of the discharge pipe (51) is closed and a plurality of stirring blades (55) are provided on its outer wall. A first magnetic plate (57) cooperating with the second magnetic plate (54) is provided on each stirring blade (55). After the driving motor (58) is started, it drives the second magnetic plate (54) to rotate, and at the same time the first magnetic plate (57) rotates synchronously therewith. Two storage tanks (61) are placed on the preparation platform (6), and a printing table (63) and a robotic arm (64) are provided on the preparation platform (6). A printing nozzle (62) connected to the two storage tanks (61) through a connecting hose is provided on the robotic arm (64).

2. The biomimetic structure preparation system based on microbially induced calcium carbonate precipitation according to claim 1, characterized in that: A straight section and a narrowing section communicating with each other are provided on the lower end surface of the aggregate bin (34). The lower end of the narrowing section is closed and its inner diameter decreases sequentially from top to bottom. The upper end of the linkage pipe (39) is connected to the closed end of the narrowing section. A disc is provided at the bottom of the exhaust pipe (33). A plurality of ventilation holes are formed on the disc. A rotating bearing is fixed on the upper surface of the middle part of the disc. The upper end of the follower rod (36) movably penetrates through the disc and extends upward. The outer wall of the follower rod (36) is connected to the inner ring of the rotating bearing and a follower fan blade (35) is provided on its extended section. A spiral blade (37) is provided on the outer wall of the follower rod (36) along its axial direction.

3. The biomimetic structure preparation system based on microbial-induced calcium carbonate precipitation according to claim 2, wherein: At least two clamping blocks (311) are provided on the inner wall of the reduced section. An annular end head plate (313) is provided on the outer edge of the upper end surface of the linkage pipe (39), and the outer circumferential wall of the end head plate (313) is connected to the inner wall of the reduced section through a flexible sealing cover (312); an axially extending sliding groove (310) which is slidably engaged with the clamping block (311) is formed in the outer wall of the upper end of the linkage pipe (39). An annular guiding groove is formed in the upper end surface of the end head plate (313), the inner diameter of the guiding groove decreases successively from top to bottom, the end surface of the large-diameter end of the guiding groove is flush with the upper surface of the end head plate (313), and the end surface of the small-diameter end of the guiding groove is flush with the upper end surface of the linkage pipe (39). A magnetic shielding cover is provided in the middle of the upper end surface of the rotating column (52), an electromagnet (512) is provided inside the magnetic shielding cover, a permanent magnet (510) which cooperates with the electromagnet (512) is provided on the lower end surface of the discharge pipe (51), a magnetic shielding bellows (511) is sleeved on the outer wall of the permanent magnet (510), and two ends of the magnetic shielding bellows (511) are respectively connected to the bottom inner wall of the mixing tank (4) and the lower end surface of the discharge pipe (51). In the initial state, the lower surface of the end head plate (313) is in contact with the upper surface of the clamping block (311), and a gap is left between the lower end of the sliding groove (310) and the lower surface of the clamping block (311).

4. The biomimetic structure preparation system based on microbial-induced calcium carbonate precipitation according to claim 2, wherein: A connecting ring (56) is provided in the mixing tank (4), and the outer ends of a plurality of stirring blades (55) are connected to the inner circumferential wall of the connecting ring (56); further included are a plurality of spiral-shaped dispersing blades (53), the upper end of each dispersing blade (53) is connected to the outer wall of the discharge pipe (51), and the lower end of the dispersing blade (53) is connected to the upper end surface of the connecting ring (56).

5. The biomimetic structure preparation system based on microbial-induced calcium carbonate precipitation according to claim 4, wherein: An exhaust pipe (41) which is internally communicated with the mixing tank (4) is further provided at the top of the mixing tank (4).

6. The biomimetic structure preparation system based on microbial-induced calcium carbonate precipitation according to claim 1, wherein: A constant-temperature heating sheet is wrapped around the outer wall of each mixing tank (4).

7. A biomimetic structure preparation system based on microbial-induced calcium carbonate precipitation according to claim 5, characterized in that: Further included is a cooling table (7), two cooling tanks (9) corresponding to the two mixing tanks (4) are provided on the cooling table (7), the mixing tank (4) is communicated with the cooling tank (9) through a liquid delivery pipeline (8), the cooling tank (9) is communicated with the storage tank (61) through a liquid inlet pipeline (10); stirrers are provided in both cooling tanks (9); a rectangular groove is formed in the lower surface of the cooling table (7), and a plurality of heat dissipation fins are arranged side by side in the rectangular groove.

8. A biomimetic structure preparation system based on microbial-induced calcium carbonate precipitation according to any one of claims 1 to 7, characterized in that: Further included is a mixing cavity. Feeding pipes are provided on each storage tank (61), peristaltic pumps are provided on the feeding pipes, the two feeding pipes are respectively communicated with the two feeding ports of the mixing cavity, and the discharging port of the mixing cavity is communicated with a connecting hose.

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