A microbial spray-drying real-time sampling cup and sampling method

Abstract

The application discloses a kind of microbial spray drying real-time sampling cup, belong to the field of spray drying, adopt heat insulation magnetic paste to simultaneously isolate the heat and magnetic exchange between cup sampling cup inside and outside, further maintain the low temperature environment in inner cup, also prevent the magnetic field of strong magnet from penetrating outer cup and attracting dry particle droplets to affect the spray drying sampling process;By connecting magnet and spray drying tower fixed, to achieve the purpose of non-destructive installation;Upper portion of inner cup, lower portion of inner cup and outer cup are filled with frozen insulation layer, maintain the low temperature environment in inner cup;Strong magnet is placed in anti-freeze liquid at the bottom of outer cup, to achieve the purpose of stable sampling by strong magnetic field to attract spray drying particle droplets loaded with microorganism and high paramagnetic carboxyl iron powder simultaneously. A kind of sampling method is also disclosed, using staircase design, avoids the interference between each sampling cup in vertical arrangement method, plus the installation of arc baffle, greatly improves the stability and accuracy of dry and wet double samples.

Description

Technical Field

[0001] This invention belongs to the field of spray drying, specifically relating to a real-time sampling cup and sampling method for microbial spray drying. Background Technology

[0002] In the spray drying process of microorganisms and other bioactive substances, research on the damage mechanisms of microorganisms during spray drying faces challenges due to the extremely short drying time, complex trajectories of spray particles (droplets), and the closed, unobservable environment. Therefore, there is a lack of direct and reasonable methods to study the changes in biomaterials during spray drying, thus hindering accurate understanding of the damage mechanisms. Consequently, current research on microbial damage mechanisms during spray drying primarily relies on two indirect methods: single-droplet drying simulation experiments and mathematical modeling. However, the conditions in single-droplet simulation experiments—such as temperature, drying rate, residual moisture content, and the speed and size of spray particles (droplets)—differ significantly from the actual conditions in the spray drying process. For example, spray drying involves faster drying rates, shorter residence times, smaller droplet sizes, and more collisions compared to single-droplet simulation experiments. Therefore, the damage mechanisms obtained from single-droplet drying simulation experiments contain significant discrepancies with actual conditions. Mathematical modeling methods for damage mechanisms require simulation based on a large amount of experimental data (usually the results of single-droplet simulation experiments). Given the inaccuracy of single-droplet simulations, the predictions made will inevitably differ significantly from the actual situation. Therefore, how to achieve stable sampling of spray particles during the spray drying process and complete real-time rehydration becomes crucial for accurately studying the damage mechanisms of microbial spray drying. Summary of the Invention

[0003] In order to overcome the shortcomings of the prior art, the present invention aims to provide a real-time sampling method and sampling cup for microbial spray drying, so as to solve the problem that the damage mechanism obtained by the single droplet drying simulation experiment in the prior art has a large error with the actual situation, and the mathematical modeling method of damage mechanism relies too much on the single droplet drying experimental data.

[0004] To achieve the above objectives, the present invention employs the following technical methods:

[0005] Compared with the prior art, the present invention has the following beneficial effects:

[0006] This invention discloses a real-time sampling cup for microbial spray drying. It employs a heat-insulating and magnetically insulating patch to simultaneously isolate heat and magnetic exchange between the inside and outside of the sampling cup. This further maintains the low-temperature environment inside the inner cup while preventing the magnetic field of a strong magnet from penetrating the outer cup and attracting the drying droplets, thus affecting the spray drying sampling process. The cup is fixed to the spray drying tower via a magnet, achieving non-destructive installation. A cryogenic insulation layer is filled between the upper and lower parts of the inner cup and the outer cup to maintain the low-temperature environment inside the inner cup. A strong magnet is placed in the antifreeze at the bottom of the outer cup to attract the spray-dried droplets simultaneously loaded with microorganisms and highly paramagnetic carboxylated iron powder, achieving stable sampling.

[0007] Furthermore, the upper part of the inner cup is a triple Bezier curved surface sampling cup, which further reduces the heat exchange between the inner cup and the outside world while ensuring sampling stability, thereby ultimately ensuring the water retention and constant temperature of the sampling cup.

[0008] Furthermore, wireless temperature and humidity sensors are used to record the sampling temperature and humidity at the sampling points in real time.

[0009] The present invention also discloses a sampling method for real-time sampling cups of microbial spray drying, which adopts a staircase design to avoid interference between sampling cups in the vertical arrangement method. In addition, the installation of arc baffles greatly improves the stability and accuracy of simultaneous sampling of dry and wet samples. Attached Figure Description

[0010] Figure 1 This is a diagram showing the arrangement of sampling cups in the sampling method of the present invention;

[0011] Figure 2 This is a schematic diagram of the sampling cup structure for the dried particles of the present invention;

[0012] Figure 3 This is a schematic diagram of the sampling principle;

[0013] Figure 4 This is a schematic diagram of the sampling cup used for rehydration sampling;

[0014] Figure 5 It is a 3D model of the sampling cup;

[0015] Figure 6 These are comparison diagrams of finite element analysis of curved sampling cups and straight sampling cups. Among them, (a) is the finite element analysis diagram of the straight sampling cup, and (b) is the cubic Bezier curved surface sampling cup.

[0016] Figure 7 This is a schematic diagram of the optimization of the cubic Bezier curve group on the upper surface of the inner cup;

[0017] Figure 8These are nine cubic Bezier curves and their experimental optimization designs 1-4;

[0018] Figure 9 These are nine cubic Bezier curves and their experimental optimization design diagrams 5-8;

[0019] Figure 10 It consists of nine cubic Bezier curves and their experimental optimization design diagram;

[0020] Figure 11 This is a design drawing for the optimal depth of the sampling cup with a low-strength magnet.

[0021] Figure 12 This is a preferred design drawing for the thickness of the low-strength magnet in the sampling cup.

[0022] The components are: 1-Sampling cup; 2-Arc-shaped baffle; 3-Heat insulation and magnetic shielding sticker; 4-Strong connecting magnet; 5-Outer cup; 6-Freezing insulation layer (automotive antifreeze); 7-Wireless temperature sensor; 8-Upper part of inner cup; 9-Lower part of inner cup; 10-Strong magnet; 11-Physiological saline; 12-Magnetic field line of action; 13-Strong magnet; 14-Spray droplets (particles). Detailed Implementation

[0023] To enable those skilled in the art to better understand the method of the present invention, the technical methods of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0024] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0025] The present invention will now be described in further detail with reference to the accompanying drawings:

[0026] This invention discloses a real-time sampling cup for microbial spray drying, comprising: a heat-insulating and magnetically shielding patch 3, a connecting magnet 4, an outer cup 5, a cryogenic insulation layer 6, an upper inner cup 8, a lower inner cup 9, and a powerful magnet 10; the upper inner cup 8 and the lower inner cup 9 are fitted inside the outer cup 5, the cryogenic insulation layer 6 is disposed between the upper inner cup 8 and the lower inner cup 9 and the outer cup 5, a powerful magnet 10 is disposed at the bottom of the outer cup 5 within the cryogenic insulation layer 6, the connecting magnet 4 is disposed on the outer wall of the outer cup 5, and a heat-insulating and magnetically shielding patch 3 is disposed on the outer surface of the outer cup 5. The connecting magnet 4, except for the end face connected to the spray drying tower, also has a heat-insulating and magnetically shielding patch 3 disposed on its outer surface. The sampling cup is used for sampling dried particles and rehydrated samples, respectively.

[0027] Sampling cup 1 for drying particles Figure 2 As shown, it mainly includes an upper inner cup 8, a lower inner cup 9, a strong magnet 10, an outer cup 5, a heat-insulating and magnetically insulating patch 3, a wireless temperature sensor 7, and a connecting magnet 4; the space between the upper inner cup 8, the lower inner cup 9, and the outer cup 5 is filled with automotive-grade -40℃ antifreeze as a freezing insulation layer 6, and is placed in a -40℃ refrigerator to be rapidly frozen into a solid state to maintain the low-temperature environment inside the inner cup; a strong magnet 10 is placed in the antifreeze at the bottom of the outer cup 5 to attract spray-dried droplets that are simultaneously loaded with microorganisms and highly paramagnetic carboxylated iron powder with a strong magnetic field to achieve the purpose of stable sampling; Heat-insulating and magnetic-insulating stickers 3 are evenly applied to the outer surface of the outer cup 5 to simultaneously isolate the heat and magnetic exchange between the inside and outside of the sampling cup. This further maintains the low-temperature environment inside the inner cup and prevents the magnetic field of the strong magnet from penetrating the outer cup and attracting dry particle droplets, thus affecting the spray drying sampling process. The sampling cup 1 is fixed to the spray drying tower by connecting magnets 4 to achieve non-destructive installation. All three surfaces of the connecting magnets 4, except for the three surfaces connected to the outer cup 5 and the spray drying tower wall, are covered with heat-insulating and magnetic-insulating stickers 3 to prevent the magnet from attracting dry particle droplets and affecting the spray drying process.

[0028] The sampling cup is made of niobium-titanium alloy for the upper part 8 and lower part 9 of the inner cup, which increases the magnetic and thermal conductivity, which is beneficial for sampling and constant temperature water retention. Meanwhile, the outer cup 5 is made of plastic, which not only ensures thermal insulation and magnetic insulation but also increases the material's ductility and prevents the cup from breaking during freeze-thaw cycles.

[0029] Meanwhile, a wireless temperature and humidity sensor 7, attached to the outer opening of the sampling cup 2, records the sampling temperature and humidity at the sampling point in real time and plots a temperature change curve. Combined with the moisture content measurement value of the particles sampled from the drying particle sampling cup, the movement trajectory of the spray particles inside the spray drying tower can be roughly obtained. Then, through mathematical modeling and fluid dynamics analysis, the flow model of the fluid inside the entire drying tower can be obtained. Based on the flow model of the airflow, mechanical structures such as bulges and baffles are added to improve the inner wall of the spray drying tower. On the one hand, this optimizes the airflow inside the spray drying tower to improve the drying quality; on the other hand, it can also improve the problem of wall adhesion during spray drying.

[0030] Sampling cup 1 for rehydrated samples, such as Figure 4 As shown, this is a modified sample cup for dried particles, with physiological saline added (11). The rest of the structure is identical to the original sample cup. The purpose of adding physiological saline is to achieve real-time and rapid rehydration of the sampled microbial particles.

[0031] See Figure 5 Here is a 3D model of sampling cup 1. The sampling principle of sampling cup 1 is as follows:

[0032] ① The strong paramagnetism of the carboxylated iron powder particles added in the microbial suspension in a pre-proportioned manner is utilized. The strong magnetic field formed by the strong magnet 10 at the bottom of the sampling cup draws the spray droplets loaded with both carboxylated iron powder and microorganisms into the bottom of the sampling cup to complete the sampling.

[0033] ② By attaching heat-insulating and magnetic-insulating stickers 3 from the inside to the outside of the outer cup, the magnetic field inside the sampling cup is isolated, thereby preventing the magnetic attraction of microbial drying particles on the surface of the outer cup and blocking the heat exchange between the inside and outside of the sampling cup, thus preventing the temperature inside the sampling cup from rising and reducing the constant temperature capacity of the sampling cup.

[0034] ③ Through heat exchange between the freezing insulation layer 6 and the upper part 8 and the lower part 9 of the inner cup, the temperature inside the inner cup is kept below 4℃ before the sampling is completed, thereby further ensuring the constant temperature capability of the dry particle sampling cup and the water retention capability of the rehydrated sample sampling cup.

[0035] ④ Based on the Bezier curve model, after optimization, a cubic curve with control points P0 = (0, 0), P1 = (12, 9), P2 = (24, -16), and P3 = (48, 8) is constructed (curve set as attached). Figure 7 The design of the first 20mm of the rotating curved surface (as shown) forms the upper part 8 of the inner cup. This design further reduces heat exchange between the inner cup and the outside environment while ensuring sampling stability, thus ultimately guaranteeing the water retention and temperature control capabilities of the sampling cup (see attached comparison with a straight-cylinder sampling cup). Figure 6 (as shown);

[0036] ⑥ By using a dedicated connecting magnet 4, the sampling cup is placed inside the spray drying tower, achieving the purpose of non-destructive installation.

[0037] ⑦ The sampling temperature at the sampling point is recorded in real time by an adhesive wireless temperature sensor 7 placed at the outer mouth of the sampling cup. A temperature change curve is plotted based on the recorded sampling temperature. Combined with the moisture content measurement value of the particles sampled from the drying particle sampling cup, the movement trajectory of the spray particles inside the spray drying tower can be roughly obtained. Then, through mathematical modeling and fluid dynamics analysis, the flow model of the fluid inside the entire drying tower can be obtained. Based on the flow model of the airflow, the inner wall of the spray drying tower is improved (by adding mechanical structures such as bulges and baffles, which optimizes the airflow inside the spray drying tower to improve the drying quality and also improves the problem of wall adhesion during spray drying).

[0038] This invention also discloses a real-time sampling method for microbial spray drying, the sampling method comprising:

[0039] S1: The sampling cup 1 for dry particles and the sampling cup 1 for rehydrated samples are arranged on the same step with a 50mm gap between them. They are responsible for collecting dry particles and rehydrating the dry particles in real time, and for non-destructive preservation.

[0040] S2: Divide the drying tower into 6 equal heights according to its height, and then divide the drying tower into 7 circular arcs according to its circumference. Arrange each step at the midpoint between the height and the circular arc, thus completing the 7-stage sampling arrangement.

[0041] S3: In order to prevent spray particles (droplets) from directly entering the sampling cup and affecting the sampling stability, arc-shaped baffles were installed 50mm directly above the mouth of each sampling cup, thus completing the design of the step-type dry and wet dual sample sampling arrangement method.

[0042] The sampling implementation steps are as follows:

[0043] 1. Inoculate the microorganisms into 12 groups of 200ml novel N medium at an inoculation ratio of 0.5%, and then place them in a constant temperature shaking incubator at 28℃ and incubate at a speed of 180r / min for 12h.

[0044] 2. Centrifuge the culture medium in batches at 4000 rpm for 10 min, remove the supernatant, collect the bacterial cells, and wash them twice with physiological saline.

[0045] 3. Resuspend the collected bacterial cells in 20 mL of PBS buffer. Then add 180 mL of culture medium containing 30% RSM to the cell suspension, and then add CIP at a ratio of CIP:RSM = 1:8 and stir well.

[0046] 4. Arrange the new curved double-cup sampling cups according to the above-mentioned new step-ladder layout scheme.

[0047] 5. Before each test, thoroughly clean all components of the spray drying system according to the cleaning requirements. Then, preheat the spray drying system for 10 minutes at the predetermined test inlet hot air temperature and flow rate to obtain stable test conditions.

[0048] 6. Set the feed pump parameters according to the predetermined material flow rate, then start the feed pump to begin the test.

[0049] 7. Record the temperature and humidity values ​​of each sampling point displayed by the acquisition system. After the test is completed, immediately remove the sample from the sampling cup, number it, and put it in a refrigerator at 4°C for later testing.

[0050] 8. Determine parameters such as moisture content, particle size distribution, and water-powder state of the dried particle samples, and parameters such as microbial survival rate, morphology, and cell damage of the rehydrated samples in the sampling cup.

[0051] 9. Mathematical modeling based on measured parameters reveals changes, movement trajectories, and damage mechanisms of microorganisms during the spray drying process.

[0052] 10. Develop a protection plan targeting the damage mechanism, and conduct a spray drying sampling test again after the protection treatment to reveal the protective mechanism of the protectant on microorganisms.

[0053] Features: This sampling method adopts a staircase-like design, which avoids interference between the sampling cups 1 in the vertical arrangement method. In addition, the installation of the arc-shaped baffle 2 greatly improves the stability and accuracy of simultaneous sampling of dry and wet samples.

[0054] Working principle:

[0055] like Figure 1 As shown, in this spray drying real-time sampling method, the dried particle sampling cup and the rehydrated sample sampling cup are arranged 50mm apart on the same step, respectively responsible for collecting dried particles and rehydrating them in real time for non-destructive preservation. The drying tower is then divided into six equal heights, and further divided into seven arcs based on its circumference. Each step is positioned at the midpoint of the height and arc, completing the seven-stage sampling arrangement. To prevent spray particles (droplets) from directly entering the sampling cups and affecting sampling stability, an arc-shaped baffle is installed 50mm directly above the opening of each sampling cup, thus completing the design of the step-type dry and wet dual-sample sampling arrangement. This sampling method, employing a step-type design, avoids interference between sampling cups in vertical arrangements. Furthermore, the installation of arc-shaped baffles greatly improves the stability and accuracy of simultaneous dry and wet sample collection.

[0056] Its overall sampling principle is as follows: Figure 3 As shown in the schematic diagram of the sampling principle, the sampling principle of this invention is to add a certain proportion of carboxylated iron powder to the spray-drying liquid so that the droplets sprayed from the nozzle and the particles in the drying process have sufficient paramagnetism; then, the spray droplets (particles) are drawn into the sampling cup by the strong magnetic field formed by the magnet at the bottom of the sampling cup at the inner cup and the cup mouth to complete the entire sampling process; at the same time, an arc-shaped baffle is arranged 50mm above the sampling cup to prevent the spray droplets (particles) from directly entering the sampling cup and affecting the sampling stability.

[0057] The combination of the staircase-shaped sampling method and the non-standard curvature sampling cup 1 structure ultimately achieved real-time stable sampling of the spray drying process, providing an effective solution for accurately studying the damage mechanism of microorganisms and other active substances during the spray drying process.

[0058] The three-dimensional model of the sampling cup is as follows Figure 5 As shown.

[0059] Finite element analysis of hot air flow field and pressure in a spray drying tower for a novel non-standard curved double-cup sampling cup and a conventional straight-cylinder sampling cup, as shown below. Figure 6 As shown in Figure (b), observing the wind speed field distribution reveals that there are almost no blue wind speed field arrows at the bottom of the curved sampling cup. This is likely because after high pressure is formed inside the sampling cup, the curved surface prevents almost any hot air from flowing into the inner cup, resulting in minimal heat exchange between the inside and outside of the cup. In contrast, the straight-cylinder sampling cup, as shown in Figure (a), although it can also form high pressure, still exhibits a small number of blue wind speed field arrows due to the absence of a curved surface, indicating heat exchange caused by hot air inflow. On the other hand, observing the pressure distribution cloud map shows that the curved sampling cup forms an outward-expanding high-pressure field along the curved surface, preventing hot air from entering the cup body from the fan-shaped area around the cup opening. In contrast, the straight-cylinder sampling cup only forms a near-straight-cylinder high-pressure field along the cup opening, failing to prevent hot air from entering the cup body from the area around the cup opening. In conclusion, under the same sampling cup size, the curved sampling cup has a higher temperature-holding capacity than the straight-cylinder sampling cup.

[0060] Figures 8-10The diagram shows nine cubic Bezier curves and their optimal experimental design. Based on the pressure cloud map, the pressure inside the cup is ordered as c>f>b>a>>d>e>g>i>h, and the diffusion range of the high-pressure zone at the cup opening is ordered as i>g>h>>d>e>f>>c>a>b. Based on the comprehensive analysis of the intermediate plane and 3D wind speed streamline diagrams, the convection rates of the hot air inside the spray tower and the air inside the cup are ordered as a>b>c>>g>d>e>h>i>f. Therefore, the optimal ranking based on the weighted ratio of air convection rate: inner cup pressure: cup opening diffusion range = 5:3:2 is: f>i>h>g>e>d>c>b>a. Therefore, this application intends to select the surface f sampling cup, which is formed by rotating the cubic Bezier two-dimensional curve determined by the control point group P0=(0,0), P1=(12,9), P2=(24,-16) and P3=(48,8), as the final experimental preferred sampling cup.

[0061] Figure 11 The optimal design for the sampling cup depth experiment was developed. After experimental comparison, the optimal sampling cup depth for this sampling method was determined to be 35mm.

[0062] Figure 12 The optimal design drawing for the thickness of the strong magnet at the bottom of the sampling cup is presented. After testing and comparison, the optimal thickness of the strong magnet at the bottom of the sampling cup used in this sampling method is 3mm.

[0063] Based on the novel dry particle sampling cup and rehydrated sample sampling cup designed according to the above-mentioned innovative spray drying sampling principle, the sampling cups were arranged in accordance with the above-mentioned real-time spray drying sampling method. After experimental verification, it can complete dual sampling of complex, rapid and closed spray drying processes of microorganisms and other active substances, laying the foundation for studying the damage mechanism of spray drying of microorganisms and other active substances.

[0064] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on the technical concept and method proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A microbial spray-drying in-process sampling cup characterized by, It comprises a heat and magnetism isolation paste (3), a connecting magnet (4), an outer cup (5), a freezing and heat preservation layer (6), an inner cup upper part (8), an inner cup lower part (9) and a strong magnet (10); the inner cup upper part (8) and the inner cup lower part (9) are sleeved in the outer cup (5), the freezing and heat preservation layer (6) is arranged between the inner cup upper part (8) and the inner cup lower part (9) and the outer cup (5), the outer cup (5) is provided with the strong magnet (10) at the bottom, the strong magnet (10) is located in the freezing and heat preservation layer (6), the connecting magnet (4) is arranged on the outer wall of the outer cup (5), the outer surface of the outer cup (5) is provided with the heat and magnetism isolation paste (3), and the heat and magnetism isolation paste (3) is also arranged on the outer surface of the connecting magnet (4) except the end surface connected with the spray drying tower; the inner cup upper part (8) is a cubic Bezier curve sampling cup; a wireless temperature sensor (7) is arranged outside the cup mouth of the outer cup (5); The freezing and heat preservation layer (6) is automobile antifreeze with a freezing point of -40℃. The inner cup upper part (8) is connected with the outer cup (5) at one end and connected with the inner cup lower part (9) at the other end; the non-standard rotary curved surface in the inner cup upper part (8) is obtained by rotating the first 20mm of the Bezier cubic curve with control points 、 、 and around the center. The inner cup upper part (8) and the inner cup lower part (9) are made of niobium-titanium alloy, and the outer cup (5) is made of plastic.

2. A microbial spray-drying in-line sampling cup according to claim 1, characterized in that The microorganism spray drying real-time sampling cup based on any one of claims 1-2 comprises:

3. A method of real-time sampling of a microbial spray-drying process, characterized in that, S1: arranging a plurality of sampling cups (1) in a stair shape; two sampling cups (1) are arranged on the same step, one is used for sampling and drying particles and performing nondestructive preservation, and the other is used for real-time rehydration of the sample and nondestructive preservation; S2: arranging an arc baffle (2) above the sampling cup (1) except the sampling cup (1) on the first step; S3: setting the parameters of the feeding pump, then starting the feeding pump, and starting the test. The sampling cup (1) for drying particles and the sampling cup (1) for rehydrated samples are arranged on the same step with a distance of 50mm.

4. A method of real-time sampling of microorganisms spray-dried, according to claim 3, characterized in that, In S1, the spray drying tower is equally divided into 6 heights according to the height, divided into 7 circular arcs according to the circumference, and each step is arranged at the middle value of each height and circular arc, completing the arrangement of 7 steps.

5. The method of claim 3, wherein the microorganism is a bacteria. ​

Images