Flow control method for a microfluidic device based on pneumatic actuation

Abstract

The application relates to a flow control method based on a gas pressure driven microfluidic device, which comprises establishing a gas conveying device and a pressure loss calculation model inside a preparation chip, then calculating required gas pressure values according to set material flow, and then monitoring actual gas pressure in a gas tank through a pressure sensor to compare the required gas pressure values with the actual gas pressure, so as to adjust the gas amount adjusting valve in real time. The application establishes an accurate mapping relationship between pressure and flow, so that the gas pressure can be automatically adjusted by input flow during preparation, not only realizing automatic, real-time and accurate regulation and control of the material flow, but also reducing the operation difficulty, improving the preparation efficiency, saving the labor cost, and standardizing and unifying the preparation process, guaranteeing the product quality and improving the enterprise benefit.

Description

Technical Field

[0001] This invention relates to a flow control method for a pneumatically driven microfluidic device, applicable to the field of microfluidic control technology. Background Technology

[0002] Microfluidic liquid preparation devices are used for preparation processes such as biochemical reactions, rapid reagent mixing, and microparticle synthesis. In traditional microfluidic preparation devices, mechanical pumps are usually used to provide driving force for material mixing. However, due to the precision errors and dead angles of the mechanical structure, the accuracy of material delivery cannot be guaranteed, and contamination is also easy to occur. Therefore, some devices use gas-driven devices to replace mechanical structures, thereby overcoming the above defects.

[0003] However, due to the low density of gases, they are significantly compressed under pressure, making it difficult to accurately correlate gas pressure with material flow rate. Furthermore, the different structures and flow resistance parameters of different fabrication chips mean that, under the same gas pressure conditions, the flow rate of materials varies in different chips. This not only makes it difficult to achieve precise control of material flow rate but also means that pneumatic microfluidic devices can usually only set pressure parameters, not flow parameters, making it difficult to standardize process parameters. In actual production, extensive debugging is required before fabrication, and manual real-time adjustments are needed during the fabrication process. This results in low fabrication efficiency, high labor costs, and poor consistency and repeatability of the fabricated products, making it difficult to meet the quality requirements of enterprises. Summary of the Invention

[0004] To address the shortcomings of the existing technology, this invention proposes a flow control method for a pneumatically driven microfluidic device.

[0005] This invention provides a flow control method based on a pneumatically driven microfluidic device, wherein the microfluidic device includes:

[0006] A chip is fabricated using materials for mixing, and its surface has a first inlet and a second inlet that are respectively connected to an internal mixing channel.

[0007] A pneumatic conveying device for conveying materials to a chip fabrication unit includes a first conveying group and a second conveying group. The first conveying group includes a first infusion pipe connected to a first inlet at one end and a first gas cylinder connected to the other end of the first infusion pipe. The second conveying group includes a second infusion pipe connected to a second inlet at one end and a second gas cylinder connected to the other end of the second infusion pipe. Both the first gas cylinder and the second gas cylinder are connected to an external gas source.

[0008] The control component, used to control the operation of the device, includes a main controller, a first pressure sensor and a second pressure sensor for real-time monitoring of the internal pressure of the first and second gas tanks, respectively, and a first gas flow regulating valve and a second gas flow regulating valve for adjusting the amount of gas input from an external gas source into the first and second gas tanks, respectively. Before preparation, the materials to be mixed are filled into the first and second infusion tubes, respectively. Then, the first and second gas flow regulating valves are opened, allowing the external gas source to supply gas into the first and second gas tanks, increasing the pressure inside the two tanks. The pressure inside the first and second gas tanks is then applied to the first and second infusion tubes, respectively, driving the materials in the two infusion tubes to enter the chip through the first and second inlets, respectively, and to mix and incubate in the mixing channels within the chip, thereby completing the preparation.

[0009] Control methods include:

[0010] S1. Establish a pressure loss calculation model inside the pneumatic conveying device, and calculate the pressure loss ΔP of the first conveying group. A,device Satisfy the following Formula 1:

[0011] ΔP A,device =8η A L A Q A ÷(πr A 4 )+K A ×ρ A v A 2 ÷2;

[0012] Pressure loss ΔP of the second conveyor group B,device The following formula two is satisfied:

[0013] ΔP B,device =8η B L B Q B ÷(πr B 4 )+K B ×ρ B v B 2 ÷2;

[0014] Where, η A η B L represents the dynamic viscosity of the material in the first and second infusion tubes, respectively. A L B Q represents the lengths of the first and second infusion tubes, respectively. A Q B r represents the material flow rate at the first inlet and the second inlet, respectively.A r B K represents the pipe radii of the first and second infusion tubes, respectively. A K B These represent the local resistance coefficients of the first and second infusion tubes, respectively. Specifically, 0 < K. A =K B ≤2,K A K B Related to factors such as changes in pipe diameter and the number of bends in the pipe, generally, as the pipe diameter decreases and the number of bends in the pipe increases, K... A K B The larger the value of ρ, the better. A ρ B v represents the density of the material in the first and second infusion tubes. A v B These represent the material flow rates at the first and second inlets, respectively.

[0015] S2. Establish a pressure loss calculation model for the inside of the fabricated chip, and calculate the pressure loss ΔP on the side corresponding to the first inlet. A,chip The following formula three must be satisfied:

[0016] ΔP A,chip = C1×Q total +C2;

[0017] Among them, Q total Q represents the total flow rate of the materials used to fabricate the chip. total =Q A +Q B C1 and C2 are coefficients;

[0018] Pressure loss ΔP on the side corresponding to the second inlet B,chip The following formula four must be satisfied:

[0019] ΔP B,chip =(Q B -C4)÷C3×ΔP A,chip ;

[0020] C3 and C4 are coefficients.

[0021] S3. Set the required material flow rate Q in the main controller according to the preparation process. A and Q B The value is then calculated by the main controller to achieve Q. A Required air pressure value P A =ΔP A,device +ΔP A,chip =8η A L A Q A ÷(πrA 4 )+K A ×ρ A v A 2 ÷2+C1×Q total +C2, and reaching Q B Required air pressure value P B =ΔP B,device +ΔP B,chip =8η B L B Q B ÷(πr B 4 )+K B ×ρ B v B 2 ÷2+(Q B -C4)÷C3×ΔP A,chip .

[0022] S4. The real-time pressure P inside the first gas tank is collected using the first pressure sensor and the second pressure sensor, respectively. a and the real-time pressure P in the second gas tank b and respectively P a With P A P b With P B Comparison:

[0023] If P a <P A If the gas volume is increased, the amount of gas input from the external gas source to the first gas tank will be increased through the first gas volume regulating valve; otherwise, the amount of gas input from the external gas source to the first gas tank will be decreased.

[0024] If P b <P B If the flow rate is increased, the amount of gas input from the external gas source to the second gas tank will be increased through the second gas volume regulating valve; conversely, if the flow rate is decreased, the amount of gas input from the external gas source to the second gas tank will be decreased.

[0025] When pressure-driven materials flow within pneumatic conveying devices or chip fabrication systems, pressure losses occur due to factors such as the material's fluid characteristics, flow channel structure, and flow resistance. The core of pneumatic actuation lies in overcoming these pressure losses with air pressure to drive material flow. Therefore, by establishing pressure loss calculation models for both pneumatic conveying devices and chip fabrication systems, a precise mapping relationship can be established between pressure and material flow rate, device structure, and chip fabrication structure. Once this precise mapping is obtained, the required air pressure to achieve the desired flow rate can be calculated in real-time during the fabrication process. The real-time pressure in the first and second air tanks can be monitored by first and second pressure sensors, respectively, allowing for real-time adjustment of the gas flow rate. This ultimately achieves automatic, real-time, and precise control of material flow rate. This control method not only improves the traditional pneumatic microfluidic equipment operation mode, which only allows setting pressure parameters, to one that allows direct setting of flow parameters, simplifying operation and reducing difficulty, but also eliminates the need for pre-fabrication debugging and manual adjustments during fabrication. This improves fabrication efficiency, reduces labor costs, ensures product consistency and repeatability, thereby improving quality and guaranteeing the company's production efficiency.

[0026] Furthermore, the calculation methods for coefficients C1, C2, C3, and C4 include:

[0027] a. Establishing a coefficient calculation model C i =C i,1 ×ΔP A,chip 2 + C i,2 ×ΔP A,chip + C i,3 ×ΔP A,chip , where C i,1 C i,2 C i,3 All are constant coefficients, i = 1, 2, 3 or 4;

[0028] b. Substitute C1, C2, C3, and C4 into the coefficient calculation model and construct the calculation polynomial:

[0029] Q A = C1×ΔP B,chip ÷ΔP A,chip + C2

[0030] C1=C 1,1 ×ΔP A,chip 2 + C 1,2 ×ΔP A,chip + C 1,3 ×ΔP A,chip

[0031] C2=C 2,1×ΔP A,chip 2 + C 2,2 ×ΔP A,chip + C 2,3 ×ΔP A,chip

[0032] Q B = C3×ΔP B,chip ÷ΔP A,chip + C4

[0033] C3=C 3,1 ×ΔP A,chip 2 + C 3,2 ×ΔP A,chip + C 3,3 ×ΔP A,chip

[0034] C4=C 4,1 ×ΔP A,chip 2 + C 4,2 ×ΔP A,chip + C 4,3 ×ΔP A,chip ;

[0035] c. Data was collected through multiple experiments, and C was calculated based on the polynomial fitting. 1,1 C 1,2 C 1,3 C 2,1 C 2,2 C 2,3 C 3,1 C 3,2 C 3,3 And C 4,1 C 4,2 C 4,3 The constant value;

[0036] d. Calculate C1, C2, C3, and C4 based on the constant values ​​obtained in step c.

[0037] Of the coefficients calculated above, coefficients C1, C2, C3, and C4 are variables that change with air pressure, while the constant coefficient C... 1,1 C 1,2 C 1,3 C 2,1 C 2,2 C 2,3 C 3,1 C 3,2 C 3,3 And C 4,1 C 4,2 C 4,3The constant coefficients mentioned above will not change once the device is finalized, as determined by the chip's structure. Therefore, by establishing a coefficient calculation model, C can be constructed. i With C i,1 C i,2 C i,3 The functional relationship between them was determined, and then actual data such as flow rate and pressure loss were collected through multiple experiments. Based on the experimental data, fitting was performed to obtain the specific values ​​of the constant coefficients, thereby determining the calculation methods of coefficients C1, C2, C3, and C4, and finally realizing ΔP. A,chip and ΔP B,chip Real-time calculation.

[0038] Furthermore, the first infusion tube has a first section connecting to the first inlet and a second section connecting to the first gas tank. The diameter of the first section is smaller than the diameter of the second section, and a first solenoid valve is installed between the first and second sections. The second infusion tube has a third section connecting to the second inlet and a fourth section connecting to the second gas tank. The diameter of the third section is smaller than the diameter of the fourth section, and a second solenoid valve is installed between the third and fourth sections. Before preparation, the first and second solenoid valves are first closed. Then, the material is added into the second and fourth sections respectively. Gas is then introduced through an external gas source to increase the gas pressure in the first and second gas tanks. Once the pressure in the two gas tanks stabilizes, the first and second solenoid valves are opened to drive the material into the chip preparation area. Dividing the first and second infusion tubes into coarse and fine sections respectively, adding material through the coarse section improves the ease of material addition; delivering material to the chip preparation area through the fine section avoids the generation of air bubbles.

[0039] Furthermore, the first infusion tube and the first gas tank, as well as the second infusion tube and the second gas tank, are designed to be detachable for easy material addition.

[0040] Furthermore, the control component also includes a first flow sensor and a second flow sensor for monitoring the amount of material input into the fabrication chip from the first inlet and the second inlet, respectively; the control method further includes:

[0041] S5. Based on the manufacturing process, set the total amount L of material input for chip fabrication from the first inlet in the main controller. A And the total amount L of materials input from the second inlet for chip fabrication B ;

[0042] S6. The actual amount of material L input into the chip preparation process from the first inlet is monitored in real time using the first flow sensor and the second flow sensor, respectively. a And the actual value L of the material input for chip fabrication from the second inlet. b and respectively L a With L A Lb With L B Comparison:

[0043] If L a <L A And L b <L B If the material is in the correct state, proceed to step S4; otherwise, the main controller will stop the device. The amount of material already involved in the preparation is monitored in real time by the first and second flow sensors, facilitating control of the preparation process and preventing the equipment from running idle.

[0044] Furthermore, the control assembly also includes a first pressure relief valve and a second pressure relief valve respectively disposed on the first gas tank and the second gas tank;

[0045] The control method also includes: setting a first air pressure safety threshold F in the main controller. A Second atmospheric pressure safety threshold F B Then P respectively a With F A P b With F B Comparison:

[0046] If P a >F A or P b >F B If the main controller shuts down the device and opens the first or second pressure relief valve to release pressure, the system can set a safe pressure threshold and monitor the pressure in the tank in real time. This allows for timely shutdown and alarm in case of equipment malfunctions such as pipeline blockage, and prompt pressure relief to prevent accidents such as explosions.

[0047] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0048] The flow control method of the pneumatically driven microfluidic device of the present invention establishes a precise mapping relationship between pressure and flow rate, so that the air pressure can be automatically adjusted by inputting the flow rate during preparation. This not only realizes automatic, real-time and precise control of material flow rate, but also reduces the difficulty of operation, improves preparation efficiency, saves labor costs, and standardizes and unifies the preparation process, ensuring product quality and improving enterprise benefits. Attached Figure Description

[0049] The following sections will describe some specific embodiments of the invention in a detailed manner, by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar components or parts. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0050] Figure 1This is a schematic diagram of the structure of a microfluidic device according to an embodiment of the present invention;

[0051] Figure 2 This is a schematic diagram of the microfluidic device from another direction in the embodiment;

[0052] The annotations in the attached figures are explained as follows:

[0053] 1. Chip fabrication; 11. First inlet; 12. Second inlet; 2. Pneumatic conveying device; 21. First infusion tube; 211. First tube segment; 212. Second tube segment; 213. First solenoid valve; 22. First gas tank; 23. Second infusion tube; 231. Third tube segment; 232. Fourth tube segment; 233. Second solenoid valve; 24. Second gas tank. Detailed Implementation

[0054] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. 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.

[0055] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0056] Reference Appendix Figure 1-2This embodiment provides a flow control method for a pneumatically driven microfluidic device. The microfluidic device includes a preparation chip 1 for mixing and preparing materials, a pneumatic conveying device 2 for conveying materials to the preparation chip 1, and a control component (not shown in the figures) for controlling the operation of the device. The preparation chip 1 has a first inlet 11 and a second inlet 12 on its surface, which are respectively connected to the internal mixing channel. The pneumatic conveying device 2 includes a first conveying group and a second conveying group. The first conveying group includes a first infusion pipe 21 connected to the first inlet 11 at one end and a first gas tank 22 connected to the other end of the first infusion pipe 21. The second conveying group includes a second infusion pipe 23 connected to the second inlet 12 at one end and a second gas tank 24 connected to the other end of the second infusion pipe 23. Both the first gas tank 22 and the second gas tank 24 are connected to an external gas source. The control component includes a main controller, a first pressure sensor and a second pressure sensor for real-time monitoring of the internal gas pressure of the first gas tank 22 and the second gas tank 24, and a first gas flow regulating valve and a second gas flow regulating valve for adjusting the amount of gas input from the external gas source to the first gas tank 22 and the second gas tank 24, respectively. Before preparation, the materials to be mixed are filled into the first infusion tube 21 and the second infusion tube 23 respectively. Then, the first gas flow regulating valve and the second gas flow regulating valve are opened to allow the external gas source to supply gas into the first gas tank 22 and the second gas tank 24 respectively, increasing the pressure inside the two gas tanks. Then, the gas pressure in the first gas tank 22 and the second gas tank 24 is used to apply pressure to the first infusion tube 21 and the second infusion tube 23 respectively, driving the materials in the two infusion tubes to enter the chip from the first inlet and the second inlet 12 of the chip preparation 1 respectively, and to be mixed and incubated in the mixing channel inside the chip preparation 1, thereby completing the preparation.

[0057] Control methods include:

[0058] S1. Establish a pressure loss calculation model inside the pneumatic conveying device 2, and calculate the pressure loss ΔP of the first conveying group. A,device Satisfy the following Formula 1:

[0059] ΔP A,device =8η A L A Q A ÷(πr A 4 )+K A ×ρ A v A 2 ÷2;

[0060] Pressure loss ΔP of the second conveyor group B,device The following formula two is satisfied:

[0061] ΔP B,device =8η B LB Q B ÷(πr B 4 )+K B ×ρ B v B 2 ÷2;

[0062] Where, η A η B The dynamic viscosity (Pa·s) of the material in the first infusion tube 21 and the second infusion tube 23 are respectively represented; L A L B Q represents the length (m) of the first infusion tube 21 and the second infusion tube 23, respectively; A Q B These represent the material flow rates (m³ / s) at the first inlet 11 and the second inlet 12, respectively; r A r B K represents the pipe radius (m) of the first infusion tube 21 and the second infusion tube 23, respectively. A K B These represent the local resistance coefficients of the first infusion tube 21 and the second infusion tube 23, respectively. Specifically, 0 < K. A =K B ≤2,K A K B Related to factors such as changes in pipe diameter and the number of bends in the pipe, generally, as the pipe diameter decreases and the number of bends in the pipe increases, K... A K B The larger the value of ρ is, the greater its relative value. A ρ B V represents the density (kg / m³) of the material in the first infusion tube 21 and the second infusion tube 23. A v B These represent the material flow velocities (m / s) at the first inlet 11 and the second inlet 12, respectively.

[0063] S2. Establish a pressure loss calculation model inside the fabricated chip 1, and calculate the pressure loss ΔP on the side corresponding to the first inlet 11. A,chip The following formula three must be satisfied:

[0064] ΔP A,chip = C1×Q total +C2;

[0065] Among them, Q total Q represents the total flow rate (m³ / s) of the material used to prepare chip 1; total =Q A +Q B C1 and C2 are coefficients;

[0066] Pressure loss ΔP on the side corresponding to the second inlet 12 B,chip The following formula four must be satisfied:

[0067] ΔP B,chip =(Q B -C4)÷C3×ΔP A,chip ;

[0068] C3 and C4 are coefficients.

[0069] S3. Set the required material flow rate Q in the main controller according to the preparation process. A and Q B The value is then calculated by the main controller to achieve Q. A Required air pressure value P A =ΔP A,device +ΔP A,chip =8η A L A Q A ÷(πr A 4 )+K A ×ρ A v A 2 ÷2+C1×Q total +C2, and reaching Q B Required air pressure value P B =ΔP B,device +ΔP B,chip =8η B L B Q B ÷(πr B 4 )+K B ×ρ B v B 2 ÷2+(Q B -C4)÷C3×ΔP A,chip .

[0070] S4. The real-time pressure P inside the first gas tank 22 is collected by the first pressure sensor and the second pressure sensor, respectively. a and the real-time pressure P in the second gas tank 24 b and respectively P a With P A P b With P B Comparison:

[0071] If P a <P AIf the gas volume is increased, the gas volume input to the first gas tank 22 from the external gas source is increased through the first gas volume regulating valve; otherwise, the gas volume input to the first gas tank 22 from the external gas source is decreased.

[0072] If P b <P B If the gas volume is increased, the amount of gas input from the external gas source to the second gas tank 24 will be increased through the second gas volume regulating valve; conversely, if the gas volume is decreased, the amount of gas input from the external gas source to the second gas tank 24 will be decreased.

[0073] When pressure-driven materials flow inside the pneumatic conveying device 2 or the fabrication chip 1, a certain degree of pressure loss will occur due to factors such as the fluid characteristics of the materials, the flow channel structure, and the flow resistance. The core of pneumatic drive lies in overcoming these pressure losses through air pressure, thereby driving the material flow. Therefore, by establishing pressure loss calculation models for the pneumatic conveying device 2 and the fabrication chip 1 respectively, a precise mapping relationship between pressure and material flow rate, device and fabrication chip structure and other factors can be established. After obtaining the precise mapping, the required air pressure can be calculated in real time during the fabrication process to achieve the current required flow rate. The real-time pressure in the first air tank 22 and the second air tank 24 can be monitored by the first pressure sensor and the second pressure sensor respectively, thereby adjusting the amount of gas introduced into the air tank in real time, and finally realizing automatic, real-time and precise control of material flow rate. By improving the control method, the traditional pneumatic microfluidic equipment, which can only set pressure parameters, can now directly set flow parameters, simplifying the operation and reducing the difficulty of operation. It also eliminates the debugging work before each preparation and eliminates the need for manual adjustment during the preparation process, thereby improving preparation efficiency, reducing labor costs, ensuring product consistency and repeatability, and thus improving quality and ensuring the production efficiency of enterprises.

[0074] In a more preferred embodiment, the coefficients C1, C2, C3, and C4 are calculated using the following method:

[0075] a. Establishing a coefficient calculation model C i =C i,1 ×ΔP A,chip 2 + C i,2 ×ΔP A,chip + C i,3 ×ΔP A,chip , where C i,1 C i,2 C i,3 All are constant coefficients, i = 1, 2, 3 or 4;

[0076] b. Substitute C1, C2, C3, and C4 into the coefficient calculation model and construct the calculation polynomial:

[0077] Q A = C1×ΔPB,chip ÷ΔP A,chip + C2

[0078] C1=C 1,1 ×ΔP A,chip 2 + C 1,2 ×ΔP A,chip + C 1,3 ×ΔP A,chip

[0079] C2=C 2,1 ×ΔP A,chip 2 + C 2,2 ×ΔP A,chip + C 2,3 ×ΔP A,chip

[0080] Q B = C3×ΔP B,chip ÷ΔP A,chip + C4

[0081] C3=C 3,1 ×ΔP A,chip 2 + C 3,2 ×ΔP A,chip + C 3,3 ×ΔP A,chip

[0082] C4=C 4,1 ×ΔP A,chip 2 + C 4,2 ×ΔP A,chip + C 4,3 ×ΔP A,chip ;

[0083] c. Data was collected through multiple experiments, and C was calculated based on the polynomial fitting. 1,1 C 1,2 C 1,3 C 2,1 C 2,2 C 2,3 C 3,1 C 3,2 C 3,3 And C 4,1 C 4,2 C 4,3 The constant value;

[0084] d. Calculate C1, C2, C3, and C4 based on the constant values ​​obtained in step c.

[0085] Of the coefficients calculated above, coefficients C1, C2, C3, and C4 are variables that change with air pressure, while the constant coefficient C... 1,1 C 1,2 C 1,3 C 2,1 C 2,2 C 2,3 C 3,1 C 3,2 C 3,3 And C 4,1 C 4,2 C 4,3 The constant coefficients mentioned above will not change once the device is finalized, as determined by the chip's structure. Therefore, by establishing a coefficient calculation model, C can be constructed. i With C i,1 C i,2 C i,3 The functional relationship between them was determined, and then actual data such as flow rate and pressure loss were collected through multiple experiments. Based on the experimental data, fitting was performed to obtain the specific values ​​of the constant coefficients, thereby determining the calculation methods of coefficients C1, C2, C3, and C4, and finally realizing ΔP. A,chip and ΔP B,chip Real-time calculation.

[0086] In a more preferred embodiment, the first infusion tube 21 has a first section 211 connecting to the first inlet 11 and a second section 212 connecting to the first gas tank 22. The diameter of the first section 211 is smaller than the diameter of the second section 212, and a first solenoid valve 213 is provided between the first section 211 and the second section 212. The second infusion tube 23 has a third section 231 connecting to the second inlet 12 and a fourth section 232 connecting to the second gas tank 24. The diameter of the third section 231 is smaller than the diameter of the fourth section 232, and a second solenoid valve 233 is provided between the third section 231 and the fourth section 232. Before preparation, the first solenoid valve 213 and the second solenoid valve 233 are closed. Then, materials are added into the second pipe section 212 and the fourth pipe section 232, respectively. Gas is then introduced through an external gas source to increase the gas pressure in the first gas tank 22 and the second gas tank 24. Once the pressure in both gas tanks stabilizes, the first solenoid valve 213 and the second solenoid valve 233 are opened to drive the materials into the prepared chip 1. The first infusion tube 21 and the second infusion tube 23 are respectively divided into coarse and fine sections. Adding materials through the coarse section improves the ease of filling; delivering materials to the prepared chip through the fine section avoids the generation of air bubbles.

[0087] In a more preferred embodiment, the first infusion tube 21 and the first gas tank 22, and the second infusion tube 23 and the second gas tank 24 are both provided as detachable connections to facilitate the addition of materials.

[0088] In a more preferred embodiment, the control component further includes a first flow sensor and a second flow sensor for monitoring the amount of material input into the fabrication chip 1 from the first inlet 11 and the second inlet 12, respectively; the control method further includes:

[0089] S5. According to the manufacturing process, set the total amount L of material for manufacturing chip 1 to be input from the first input 11 in the main controller. A And the total amount L of material for preparing chip 1 input from the second inlet 12 B ;

[0090] S6. The actual amount of material L input into the chip preparation 1 from the first inlet 11 is monitored in real time by the first flow sensor and the second flow sensor respectively. a And the actual value L of the material quantity for preparing chip 1 is input from the second inlet 12. b and respectively L a With L A L b With L B Comparison:

[0091] If L a <L A And L b <L B If the material is in the correct state, proceed to step S4; otherwise, the main controller will stop the device. The amount of material already involved in the preparation is monitored in real time by the first and second flow sensors, facilitating control of the preparation process and preventing the equipment from running idle.

[0092] In a more preferred embodiment, the control assembly further includes a first pressure relief valve and a second pressure relief valve respectively disposed on the first gas tank 22 and the second gas tank 24;

[0093] The control method also includes: setting a first air pressure safety threshold F in the main controller. A Second atmospheric pressure safety threshold F B Then P respectively a With F A P b With F B Comparison:

[0094] If P a >F A or P b >F B If the main controller shuts down the device and opens the first or second pressure relief valve to release pressure, the system can set a safe pressure threshold and monitor the pressure in the tank in real time. This allows for timely shutdown and alarm in case of equipment malfunctions such as pipeline blockage, and prompt pressure relief to prevent accidents such as explosions.

[0095] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0096] The flow control method of the pneumatically driven microfluidic device of the present invention establishes a precise mapping relationship between pressure and flow rate, so that the air pressure can be automatically adjusted by inputting the flow rate during preparation. This not only realizes automatic, real-time and precise control of material flow rate, but also reduces the difficulty of operation, improves preparation efficiency, saves labor costs, and standardizes and unifies the preparation process, ensuring product quality and improving enterprise benefits.

[0097] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A flow control method based on a pneumatically driven microfluidic device, the microfluidic device comprising: The chip (1) is used to mix the preparation materials and has a first inlet (11) and a second inlet (12) on its surface that are respectively connected to the internal mixing channel. A pneumatic conveying device (2) is used to convey materials to the chip preparation (1). It includes a first conveying group and a second conveying group. The first conveying group includes a first infusion pipe (21) connected to a first inlet (11) at one end and a first gas tank (22) connected to the other end of the first infusion pipe (21). The second conveying group includes a second infusion pipe (23) connected to a second inlet (12) at one end and a second gas tank (24) connected to the other end of the second infusion pipe (23). Both the first gas tank (22) and the second gas tank (24) are connected to an external gas source. The control components are used to control the operation of the device, including a main controller, a first pressure sensor and a second pressure sensor for real-time monitoring of the internal air pressure of the first gas tank (22) and the second gas tank (24), and a first gas volume regulating valve and a second gas volume regulating valve for adjusting the amount of gas input from the external gas source into the first gas tank (22) and the second gas tank (24), respectively. The control method is characterized by comprising: S1. Establish a pressure loss calculation model inside the pneumatic conveying device (2), and calculate the pressure loss ΔP of the first conveying group. A,device Satisfy the following Formula 1: ΔP A,device =8η A L A Q A ÷(πr A 4 )+K A ×ρ A v A 2 ÷2; Pressure loss ΔP of the second conveying group B,device satisfies the following equation two: ΔP B,device =8η B L B Q B ÷(πr B 4 )+K B ×ρ B v B 2 ÷2; Where, η A η B L represents the dynamic viscosity of the material in the first infusion tube (21) and the second infusion tube (23), respectively. A L B Q represents the lengths of the first infusion tube (21) and the second infusion tube (23), respectively. A Q B r represents the material flow rate at the first inlet (11) and the second inlet (12), respectively. A r B K represents the pipe radius of the first infusion tube (21) and the second infusion tube (23), respectively. A K B ρ represents the local resistance coefficient of the first infusion tube (21) and the second infusion tube (23), respectively. A ρ B v represents the density of the material in the first infusion tube (21) and the second infusion tube (23). A v B These represent the material flow velocities at the first inlet (11) and the second inlet (12), respectively. S2. Establishing a pressure loss calculation model inside the preparation chip (1), and the pressure loss ΔP of the side corresponding to the first inlet (11) A,chip Satisfying the following formula three: ΔP A,chip = C1x Q total + C2; where Q total represents the total flow of material input into the production chip (1), Q total = Q A + Q B , C1 and C2 are coefficients; Pressure loss ΔP on the side corresponding to the second inlet (12) B,chip Satisfy Equation Four below: ΔP B,chip =(Q B -C4)÷C3×ΔP A,chip ; Where C3 and C4 are coefficients; S3. Set the required material flow rate Q in the main controller. A and Q B The value is then calculated by the main controller to achieve Q. A Required air pressure value P A =ΔP A,device +ΔP A,chip =8η A L A Q A ÷(πr A 4 )+K A ×ρ A v A 2 ÷2+ C1×Q total +C2, and reaching Q B Required air pressure value P B =ΔP B,device +ΔP B,chip =8η B L B Q B ÷(πr B 4 )+K B ×ρ B v B 2 ÷2+(Q B -C4)÷C3×ΔP A,chip ; S4. Collect the real-time pressure P in the first gas tank (22) respectively. a and the real-time pressure P in the second gas tank (24) b and respectively P a With P A P b With P B Comparison: If P a If P A If P If P b <P B If the gas volume is increased, the amount of gas input from the external gas source to the second gas tank (24) will be increased through the second gas volume regulating valve; otherwise, the amount of gas input from the external gas source to the second gas tank (24) will be decreased. 2.The flow control method of a gas pressure-driven microfluidic device according to claim 1, wherein, The calculation methods for coefficients C1, C2, C3, and C4 include: a. Establishing a coefficient calculation model C i =C i,1 ×ΔP A,chip 2 + C i,2 ×ΔP A,chip + C i,3 ×ΔP A,chip , where C i,1 C i,2 C i,3 All are constant coefficients, i = 1, 2, 3 or 4; b. Substitute C1, C2, C3, and C4 into the coefficient calculation model and construct the calculation polynomial: Q A = C1×ΔP B,chip ÷ΔP A,chip + C2 C1 = C 1,1 x ΔP A,chip 2 + C 1,2 x ΔP A,chip + C 1,3 x ΔP A,chip C2=C 2,1 ×ΔP A,chip 2 + C 2,2 ×ΔP A,chip + C 2,3 ×ΔP A,chip Q B = C3×ΔP B,chip ÷ΔP A,chip + C4 C3=C 3,1 ×ΔP A,chip 2 + C 3,2 ×ΔP A,chip + C 3,3 ×ΔP A,chip C4 = C 4,1 x ΔP A,chip 2 + C 4,2 x ΔP A,chip + C 4,3 x ΔP A,chip ; c. Data was collected through multiple experiments, and C was calculated based on the polynomial fitting. 1,1 C 1,2 C 1,3 C 2,1 C 2,2 C 2,3 C 3,1 C 3,2 C 3,3 And C 4,1 C 4,2 C 4,3 The constant value; d. Calculate C1, C2, C3, and C4 based on the constant values ​​obtained in step c.

3. The flow control method of the pneumatically driven microfluidic device according to claim 1, characterized in that: The first infusion tube (21) has a first pipe section (211) connected to the first inlet (11) and a second pipe section (212) connected to the first gas tank (22). The diameter of the first pipe section (211) is smaller than the diameter of the second pipe section (212), and a first solenoid valve (213) is provided between the first pipe section (211) and the second pipe section (212). 4.The flow control method of the barometric pressure-driven microfluidic device according to claim 1, wherein: The second infusion tube (23) has a third tube section (231) connected to the second inlet (12) and a fourth tube section (232) connected to the second gas tank (24). The diameter of the third tube section (231) is smaller than the diameter of the fourth tube section (232), and a second solenoid valve (233) is provided between the third tube section (231) and the fourth tube section (232). 5.The flow control method of the barometric pressure-driven microfluidic device according to claim 1, wherein: The first infusion tube (21) and the first gas tank (22), and the second infusion tube (23) and the second gas tank (24) are both detachably connected. 6.The flow control method of the barometric pressure-driven microfluidic device according to claim 1, wherein: The control component also includes a first flow sensor and a second flow sensor for monitoring the amount of material input into the preparation chip (1) from the first inlet (11) and the second inlet (12), respectively; The control method further includes: S5. Set the total amount L of material input into the preparation chip (1) from the first inlet (11) in the master controller according to the preparation process A and the total amount L of material input into the preparation chip (1) from the second inlet (12) according to the preparation process B ; S6. The actual amount of material L input into the chip preparation (1) from the first inlet (11) is monitored in real time by the first flow sensor and the second flow sensor respectively. a And the actual value L of the material quantity input from the second inlet (12) for preparing the chip (1) b and respectively L a With L A L b With L B Comparison: If L a <L A , and L b <L B , then the step S4 is continued, otherwise the main controller controls the device to stop. 7.The flow control method of the barometric pressure-driven microfluidic device according to claim 1, wherein: The control assembly also includes a first pressure relief valve and a second pressure relief valve respectively disposed on the first gas tank (22) and the second gas tank (24); The control method further includes: setting a first air pressure safety threshold F in the main controller. A Second atmospheric pressure safety threshold F B Then P respectively a With F A P b With F B Comparison: If P a >F A or P b >F B If the main controller stops the device and opens the first or second pressure relief valve to release pressure.

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