Microfluidic experimental devices and methods with low residual volume

Abstract

The embodiment of the application provides a microfluidic experimental device with low residual volume and a method, and relates to the technical field of oil and gas development. The experimental device comprises a microfluidic chip, a micro-reactor, a delivery structure, and a bypass pipeline. The microfluidic chip is installed in the micro-reactor. The delivery structure comprises a valve needle, a delivery pipeline, and a bypass pipeline. The valve needle is inserted into the micro-reactor and is in sealed connection with the inlet of the microfluidic chip. The ports of the delivery pipeline and the bypass pipeline are connected with the valve needle. The delivery pipeline is used for delivering experimental medium into the microfluidic chip. When the valve needle is opened, the delivery pipeline is in communication with the microfluidic chip. When the valve needle is closed, the inlet of the microfluidic chip is closed, and the delivery pipeline is in communication with the bypass pipeline to discharge the experimental medium in the delivery pipeline, so as to prevent the mixed medium from entering the chip and to prevent the medium from reacting in advance in the microfluidic chip, thereby realizing pure displacement, ensuring experimental accuracy and repeatability.

Description

Technical Field

[0001] This application relates to the field of oil and gas development experimental technology, and in particular to a microfluidic experimental device and method with low residual volume. Background Technology

[0002] Microfluidic experiments, due to their microscopic visualization capabilities, are widely used in the study of reservoir multiphase flow and phase changes in the oil and gas development field. Specifically, microfluidic experimental setups are frequently used in research on reservoir multiphase flow or phase changes.

[0003] In related technologies, microfluidic experimental devices include a microreactor, a microfluidic chip, a delivery line, an output line, and two valves. The microfluidic chip is embedded inside the microreactor, and both valves are located outside the reactor. One valve is connected to the inlet of the microfluidic chip via the delivery line, and the other valve is connected to the outlet of the microfluidic chip via the output line. The valves control the injection and discharge of the experimental medium into and out of the microfluidic chip.

[0004] However, there is a pipeline between the valve and the microfluidic chip, in which experimental media remain. Furthermore, the volume of this pipeline is larger than the pore volume of the microfluidic chip. This causes the subsequently injected experimental media to mix with the residual experimental media in the pipeline before entering the microfluidic chip, affecting experimental accuracy and repeatability. Additionally, the subsequently injected experimental media prematurely extracts from the existing media within the microfluidic chip within the pipeline, altering the original experimental media before the formal reaction begins, thus affecting the purity of the experimental media and experimental accuracy. Summary of the Invention

[0005] This application provides a microfluidic experimental apparatus and method with low residual volume to overcome the problems in the prior art where there is a pipeline between the valve and the microfluidic chip, with residual experimental medium in the pipeline, and the volume of the pipeline is larger than the pore volume of the microfluidic chip. This causes the subsequently injected experimental medium to mix with the residual experimental medium in the pipeline before entering the microfluidic chip, affecting experimental accuracy and repeatability. Furthermore, the subsequently injected experimental medium may prematurely extract with the original medium in the microfluidic chip within the pipeline, causing changes in the original experimental medium in the microfluidic chip before the formal reaction begins, affecting the purity of the experimental medium and experimental accuracy.

[0006] In a first aspect, embodiments of this application provide a microfluidic experimental device with low residual volume, comprising: a microfluidic chip; a microreactor, wherein the microfluidic chip is installed inside the microreactor; and a delivery structure, wherein the delivery structure includes a valve needle, a delivery line, and a bypass line, the valve needle being inserted into the microreactor and sealed to the inlet of the microfluidic chip, the ports of the delivery line and the bypass line being connected to the valve needle, and the delivery line being used to deliver experimental media into the microfluidic chip.

[0007] The delivery structure is configured such that when the valve needle is open, the delivery line is connected to the microfluidic chip; when the valve needle is closed, the inlet of the microfluidic chip is sealed, and the delivery line is connected to the bypass line to discharge the experimental medium in the delivery line.

[0008] The microreactor is used to heat and pressurize the experimental medium within the microfluidic chip.

[0009] In one possible implementation, the valve needle includes a valve needle body and a valve handle. The valve needle body is inserted into the microreactor, and the end of the valve needle body has a tapered sealing surface, which is hard-sealed to the inlet of the microfluidic chip.

[0010] The valve handle is connected to the valve needle body, and the valve handle is located outside the microreactor.

[0011] In one possible implementation, the valve needle body has micro-nano channels, the microfluidic chip has micro-reaction channels, and the central hole at the end of the valve needle body is connected to the micro-nano channels through the micro-nano channels and the micro-reaction channels.

[0012] In one possible implementation, the valve needle further includes an elastic guide, which is mounted on the valve needle body and connected to the microreactor. The elastic guide is used to limit the offset of the valve needle body.

[0013] In one possible implementation, a detector is also included, which is connected to the bypass pipeline and is used to detect whether residual experimental medium in the delivery pipeline is discharged through the bypass pipeline.

[0014] In one possible implementation, the detector is a flow meter or a spectrometer.

[0015] In one possible implementation, the system further includes a controller. The delivery structure is provided in at least two sets. The valves of the delivery structure are connected to the inlet and outlet of the microfluidic chip respectively. Each set of delivery structures is electrically connected to the controller. The controller is used to control the valves to open or close the inlet and outlet of the microfluidic chip.

[0016] In one possible implementation, the valve needle is a steel valve needle.

[0017] In one possible implementation, the device further includes an etching element for etching the surface of the microfluidic chip to form micro-reaction channels for receiving the experimental medium.

[0018] Secondly, this application provides a microfluidic experimental method with low residual volume, employing the microfluidic experimental apparatus with low residual volume as provided in the first aspect. The microfluidic experimental apparatus with low residual volume includes a microfluidic chip, a microreactor, and a delivery structure. The delivery structure includes a valve needle, a delivery line, and a bypass line. The method includes the following steps.

[0019] The microfluidic chip is installed inside the microreactor. The valve needle is opened, the delivery line is opened, and the bypass line is closed. The first experimental medium is delivered into the microfluidic chip through the delivery line.

[0020] The valve needle is closed, the inlet of the microfluidic chip is sealed, the bypass line is opened, the delivery line is connected to the bypass line, and the second experimental medium is delivered into the delivery line, which drives the first experimental medium and the second experimental medium in the delivery line to be discharged through the bypass line until the delivery line is filled with the second experimental medium.

[0021] Open the valve needle and close the bypass line, and the second experimental medium is delivered into the microfluidic chip via the delivery line.

[0022] This application provides a microfluidic experimental apparatus and method with low residual volume. The low residual volume microfluidic experimental apparatus inserts a valve needle into a microreactor and seals it to the inlet of the microfluidic chip, eliminating the need for additional connecting tubing between the valve needle and the microfluidic chip, thus minimizing the flow path length from the valve needle to the microfluidic chip inlet. Furthermore, closing the valve needle seals the microfluidic chip, and the delivery line is directly connected to the bypass line, allowing residual experimental medium in the delivery line to be discharged. This prevents residual experimental medium from mixing with newly injected experimental medium and entering the microfluidic chip, ensuring that only the newly injected experimental medium reacts with the experimental medium within the microfluidic chip during the experiment, thereby improving experimental accuracy and repeatability. On the other hand, it prevents the newly injected experimental medium from interacting with the experimental medium within the microfluidic chip before entering the chip, avoiding changes in the composition and properties of the experimental medium within the microfluidic chip before the formal reaction begins, ensuring the purity and concentration accuracy of the experimental medium in each experiment, and thus guaranteeing experimental precision. Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0024] Figure 1 A schematic diagram of the microfluidic experimental device with low residual volume provided in this application;

[0025] Figure 2 A partial structural schematic diagram of the microfluidic experimental device with low residual volume provided in this application;

[0026] Figure 3 A partial structural schematic diagram of the microfluidic experimental device with low residual volume provided in this application;

[0027] Figure 4 for Figure 3 A bottom view of point A in the middle.

[0028] Explanation of reference numerals in the attached figures:

[0029] 100-Microfluidic chip;

[0030] 200-microreactor;

[0031] 300 - Delivery structure; 310 - Valve needle; 311 - Valve needle body; 3111 - Conical sealing surface; 312 - Valve handle; 313 - Micro / nano channel; 314 - Elastic guide; 320 - Delivery line; 330 - Bypass line;

[0032] 400-detector;

[0033] 500-Controller.

[0034] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0035] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0036] The terms "first," "second," "third," etc. (if present) in the specification, claims, and accompanying drawings of this application 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 this application described herein can be implemented in orders other than those illustrated or described herein.

[0037] Secondly, it should be noted that in the description of this application, the terms "inner", "outer", "first direction", "second direction", etc., indicating the direction or positional relationship are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this application.

[0038] Furthermore, it should be noted that, in the description of this application, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0039] As shown in the background section, the microfluidic experimental apparatus includes a reaction vessel, a microfluidic chip, a delivery line, an output line, and two valves. The microfluidic chip is embedded inside the reaction vessel, and both valves are located outside the reaction vessel. One valve is connected to the inlet of the microfluidic chip via the delivery line, and the other valve is connected to the outlet of the microfluidic chip via the output line. The valves control the injection and discharge of the experimental medium into and out of the microfluidic chip.

[0040] Specifically, for example, during displacement experiments, water and crude oil can be injected into the microfluidic chip through delivery pipelines, and pressurized and heated using a reactor to simulate the actual formation environment; then, displacement media (such as carbon dioxide) can be injected into the microfluidic chip through delivery pipelines. Taking advantage of the properties of carbon dioxide, such as causing crude oil volume expansion, viscosity reduction, and extraction of light components from crude oil, more crude oil can be displaced.

[0041] It is evident that during the experiment, various experimental media (such as crude oil and carbon dioxide) need to be delivered to the microfluidic chip through the delivery pipeline, and different experimental media will interact with each other.

[0042] However, there is a delivery line between the valve and the microfluidic chip. The experimental medium remains in the delivery line. When the valve is opened, the experimental medium injected later mixes or is retained with the residual experimental medium in the delivery line before entering the microfluidic chip. As a result, the microfluidic chip contains the original experimental medium (saturated oil) and the displacement medium mixed in the delivery line, resulting in an impure displacement experiment and affecting the experimental accuracy.

[0043] Furthermore, the wall thickness of the microreactor is large. In microfluidic displacement experiments of crude oil in tight oil reservoirs, the pore volume inside the microfluidic chip is smaller than the volume of a section of delivery pipeline that penetrates the reactor wall. Moreover, the residence time of the subsequently injected experimental medium in this delivery pipeline is long. This causes the subsequently injected experimental medium (such as carbon dioxide) to prematurely extract from the original medium (saturated oil) in the microfluidic chip, changing the composition and properties of the saturated oil in the microfluidic chip. As a result, the initial conditions in the microfluidic chip are difficult to accurately control and reproduce, affecting the reliability and comparability of the experimental results.

[0044] In addition, the experimental media injected later cannot completely replace the media in the delivery pipeline at one time. Therefore, during the displacement process, both new and old experimental media are injected at the same time, which affects the experimental accuracy and the observation of the experimental process.

[0045] To address the aforementioned technical problems, this application provides a microfluidic experimental device with low residual volume, comprising: a microfluidic chip; a microreactor, wherein the microfluidic chip is installed inside the microreactor; a delivery structure, comprising a valve needle, a delivery line, and a bypass line, wherein the valve needle is inserted into the microreactor and is sealed to the inlet of the microfluidic chip, and the ports of the delivery line and the bypass line are both connected to the valve needle, the delivery line being used to deliver experimental media into the microfluidic chip; the delivery structure is configured such that, when the valve needle is open, the delivery line is connected to the microfluidic chip, and when the valve needle is closed, the inlet of the microfluidic chip is sealed, and the delivery line is connected to the bypass line to discharge the experimental media within the delivery line; the microreactor is used to heat and pressurize the experimental media within the microfluidic chip.

[0046] By inserting the valve needle into the microreactor and sealing it with the inlet of the microfluidic chip, the additional connecting tubing between the valve needle and the microfluidic chip is eliminated, minimizing the flow path length from the valve needle to the microfluidic chip inlet. Furthermore, closing the valve needle seals the microfluidic chip, allowing direct connection between the delivery line and the bypass line. This removes residual experimental media from the delivery line, preventing mixing, extraction, or phase interference between the residual experimental media and the newly injected experimental media. This ensures the purity and concentration accuracy of the experimental media in each experiment, thereby guaranteeing experimental precision.

[0047] Furthermore, the valve needle is sealed to the inlet of the microfluidic chip, and the delivery line is directly connected to the bypass line when the valve is closed. This ensures that when carbon dioxide is injected for displacement experiments, the carbon dioxide does not carry oil into the microfluidic chip and does not prematurely extract the saturated oil in the microfluidic chip, thus ensuring the purity and concentration accuracy of the experimental medium and ensuring the accuracy of subsequent experimental results.

[0048] In addition, it should be noted that the flushing of the delivery pipeline can be completed without additional disassembly, which shortens the preparation time between experiments, improves the continuity of the experimental process, and avoids the residual medium from deteriorating under high temperature and high pressure and affecting subsequent experiments.

[0049] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0050] In a first aspect, embodiments of this application provide a microfluidic experimental device with low residual volume, combined with Figures 1 to 3 As shown, it includes: a microfluidic chip 100; a microreactor 200, wherein the microfluidic chip 100 is installed inside the microreactor 200.

[0051] The delivery structure 300 includes a valve needle 310, a delivery line 320, and a bypass line 330. The valve needle 310 is inserted into the microreactor 200 and is sealed to the inlet of the microfluidic chip 100. The ports of the delivery line 320 and the bypass line 330 are both connected to the valve needle 310. The delivery line 320 is used to deliver experimental media into the microfluidic chip 100.

[0052] The delivery structure 300 is configured such that when the valve needle 310 is open, the delivery line 320 is connected to the microfluidic chip 100; when the valve needle 310 is closed, the inlet of the microfluidic chip 100 is sealed, and the delivery line 320 is connected to the bypass line 330 to discharge the experimental medium in the delivery line 320.

[0053] The microreactor 200 is used to heat and pressurize the experimental medium inside the microfluidic chip 100.

[0054] Understandably, by inserting the valve needle 310 into the microreactor 200 and sealing it with the inlet of the microfluidic chip 100, the additional connecting pipe between the valve needle 310 and the microfluidic chip 100 is eliminated, minimizing the flow path length from the valve needle 310 to the inlet of the microfluidic chip 100. Furthermore, closing the valve needle 310 seals the microfluidic chip 100, isolating it from the delivery structure 300. The delivery line 320 is directly connected to the bypass line 330, allowing residual experimental medium in the delivery line 320 to be discharged. This prevents the residual experimental medium from mixing with the newly injected experimental medium and entering the microfluidic chip 100, ensuring that only the newly injected experimental medium itself reacts with the experimental medium in the microfluidic chip 100 during the experiment, thereby improving experimental accuracy and repeatability.

[0055] Furthermore, the valve needle 310 is sealed to the inlet of the microfluidic chip 100, and the delivery line 320 is directly connected to the bypass line 330 when the valve needle 310 is closed. This ensures that when carbon dioxide is injected for displacement experiments, carbon dioxide does not carry oil into the microfluidic chip 100 and does not prematurely extract the saturated oil in the microfluidic chip 100, thus ensuring the purity and concentration accuracy of the experimental medium and ensuring the accuracy of subsequent experimental results.

[0056] In addition, it should be noted that flushing of the delivery pipeline 320 can be completed without additional disassembly of the pipeline, which shortens the preparation time between experiments, improves the continuity of the experimental process, and avoids the residual medium from deteriorating under high temperature and high pressure and affecting subsequent experiments.

[0057] In one possible implementation, combining Figure 3 and Figure 4 As shown, the valve needle 310 includes a valve needle body 311 and a valve handle 312. The valve needle body 311 is inserted into the microreactor 200, and the end of the valve needle body 311 has a conical sealing surface 3111, which is hard-sealed to the inlet of the microfluidic chip 100.

[0058] The valve handle 312 is connected to the valve needle body 311, and the valve handle 312 is located outside the micro reactor 200.

[0059] It is understandable that, such as Figure 3The diagram shows a cross-sectional view of the entire microfluidic experimental device with low residual volume along the horizontal axis. The inlet of the microfluidic chip 100 can be fitted with a tapered orifice at the end of the valve needle body 311. The tapered sealing surface 3111 of the valve needle body 311 is hard-sealed to the inlet of the microfluidic chip 100. The tapered structure can increase the sealing pressure through surface contact, forming a tightly fitting sealing interface. The hard seal can withstand the high temperature and high pressure environment inside the microreactor 200, avoiding leakage caused by aging and deformation of the valve needle 310 under high temperature and high pressure conditions. This ensures that when the valve needle 310 is closed, it completely blocks the leakage of experimental media or the intrusion of external gases into the microfluidic chip 100, guaranteeing the stability and safety of experimental conditions.

[0060] Furthermore, combined Figure 3 and Figure 4 As shown, the valve handle 312 is located outside the microreactor 200, allowing direct control of the valve needle body 311 from outside the microreactor 200, simplifying the experimental operation process. The valve handle 312 is designed to provide clear torque feedback for operation, facilitating precise control of the opening and closing degree of the valve needle body 311, so as to open or close the microfluidic chip 100 and avoid gaps between the valve needle body 311 and the microfluidic chip 100.

[0061] Furthermore, such as Figure 2 As shown, the valve needle body 311 has a micro-nano channel 313, and the microfluidic chip 100 has a micro-reaction channel. The central hole at the end of the valve needle body 311 is connected to the micro-reaction channel through the micro-nano channel 313.

[0062] Understandably, referring to Figure 2 The figure shows a cross-sectional view of the entire microfluidic experimental device with low residual volume along the vertical axis. The microfluidic chip 100 has a micro-reaction channel, which is connected to the inlet of the microfluidic chip 100. The diameter of the conical inlet hole of the microfluidic chip 100 is slightly larger than the diameter of the micro-reaction channel, so that the conical sealing surface 3111 of the valve needle body 311 fits tightly with the conical inlet hole of the microfluidic chip 100, thereby avoiding sealing failure and leakage of experimental medium under high temperature and high pressure.

[0063] Furthermore, a micro-nano channel 313 is connected to the central hole at the end of the valve needle body 311. The micro-nano channel 313 is inserted into the micro-reaction channel to achieve precise delivery and distribution of trace experimental media.

[0064] Furthermore, the outlet aperture of the micro-nano channel 313 is consistent with the aperture of the micro-reaction channel, and the volume of the micro-nano channel 313 is much smaller than the volume of the micro-reaction channel inside the microfluidic chip 100. This avoids mixing of experimental media within the micro-nano channel 313, effectively reduces the flow volume between the valve and the microfluidic chip 100, and ensures the purity and concentration accuracy of the experimental media in each experiment, thereby guaranteeing experimental accuracy.

[0065] In one possible implementation, such as Figure 3 As shown, the valve needle 310 also includes an elastic guide 314, which is mounted on the valve needle body 311 and connected to the microreactor 200. The elastic guide 314 is used to limit the offset of the valve needle body 311.

[0066] Specifically, such as Figure 3 As shown, the elastic guide 314 is sleeved on the valve needle body 311 and abuts against the microreactor 200, providing radial support for the valve needle body 311. This can limit the radial offset or tilt of the valve needle body 311 during high temperature, pressure fluctuations or operation, ensuring that the conical sealing surface 3111 of the valve needle body 311 is always aligned with the inlet center of the microfluidic chip 100, avoiding sealing failure caused by offset.

[0067] Furthermore, the elastic guide 314 has elastic deformation capability, which can absorb the stress caused by vibration and temperature cycling in the microreactor 200, reduce the impact of these disturbances on the positioning accuracy of the valve needle body 311, and avoid gaps between the valve needle body 311 and the inlet of the microfluidic chip 100.

[0068] Furthermore, it should be noted that the mating surfaces of the elastic guide 314, the valve needle body 311, and the microreactor 200 can form an auxiliary sealing effect, preventing external impurities from entering the microreactor 200 and reducing wear on the insertion surfaces of the valve needle body 311 and the microreactor 200. Together with the valve needle body 311, this forms a dual guarantee of "guidance + sealing," further preventing leakage of the experimental medium under high temperature and pressure, and enhancing the long-term stability of the seal.

[0069] In one possible implementation, such as Figure 2 As shown, it also includes a detector 400, which is connected to the bypass line 330. The detector 400 is used to detect whether the experimental medium remaining in the delivery line 320 is discharged through the bypass line 330.

[0070] Specifically, refer to Figure 2 As shown, both the delivery line 320 and the bypass line 330 are connected to the valve needle 310. When the valve needle 310 is closed, the microfluidic chip 100 is sealed. The delivery line 320 and the bypass line 330 are connected. Cleaning fluid can be injected into the delivery line 320. The cleaning fluid flows along the delivery line 320 to the bypass line 330 and is discharged to the outside.

[0071] The detector 400 is connected to the bypass line 330. The detector 400 can directly monitor the discharge status of the residual experimental medium through the bypass line 330. The detector 400 can be preset with a threshold. When the discharged experimental medium reaches the threshold, the cleaning is determined to be complete, thus avoiding "blind discharge".

[0072] Furthermore, by replacing subjective human judgment with objective feedback from the detector 400, the criteria for determining complete residue removal are clearly defined, making the experimental process more standardized and facilitating experimental reproduction and data traceability. Simultaneously, the removal progress can be monitored in real time, eliminating the need for prolonged waiting periods; the next round of experiments can be started immediately after residue removal, shortening the process cycle and improving experimental efficiency.

[0073] In addition, it should be noted that the cleaning solution can be used to inject new experimental media. After the residual experimental media is discharged through the bypass line 330, the delivery line 320 is filled with the new experimental media to be injected. The valve needle 310 can be used to directly deliver the new experimental media into the microfluidic chip 100, thereby reducing delivery time and improving efficiency.

[0074] Furthermore, detector 400 is a flow meter or a spectrometer.

[0075] Specifically, detector 400 can be a flow meter to quantify the flow rate and volume of the experimental medium discharged through bypass line 330. When the threshold set in advance by detector 400 is reached, the cleaning is confirmed to be complete, preventing residue from mixing with the next round of experimental medium and affecting the accuracy of the experiment.

[0076] Of course, detector 400 can also be a spectrometer, which can qualitatively detect changes in the composition of the experimental medium discharged through bypass line 330 and accurately identify whether there is any target residual experimental medium.

[0077] In one possible implementation, such as Figure 1 and Figure 2 As shown, it also includes a controller 500, and at least two sets of conveying structures 300 are provided. The valve needles 310 of the conveying structures 300 are connected to the inlet and outlet of the microfluidic chip 100. Each set of conveying structures 300 is electrically connected to the controller 500. The controller 500 is used to control the valve needles 310 to open or close the inlet and outlet of the microfluidic chip 100.

[0078] Specifically, such as Figure 1 and Figure 2 As shown, the conveying structure 300 can be configured in two sets, with its valve needle 310 connected to the inlet and outlet of the microfluidic chip 100 respectively, and the valve needle 310 of each set of conveying structures 300 is electrically connected to the controller 500.

[0079] Understandably, the controller 500 can preset different control logics and set the opening and closing intervals and synchronous / asynchronous control modes of the valve needles 310 at the inlet and outlet of the microfluidic chip 100 to meet the stringent requirements of different reaction systems for experimental medium delivery and residence time, without the need for manual adjustment, thus improving the flexibility and adaptability of the experiment.

[0080] In addition, it should be noted that a driving component is also included. The driving component is connected to the valve needle 310 and is electrically connected to the controller 500. The controller 500 can control the driving component to move the corresponding valve needle 310 to open or close the inlet or outlet of the microfluidic chip 100. The driving component can be a motor, stepper motor, or electromagnetic actuator, etc., without specific limitations.

[0081] In one possible implementation, the valve needle 310 is a steel valve needle.

[0082] Understandably, the valve needle 310 is made of high-temperature and high-pressure resistant steel to ensure that the valve needle 310 inserted into the microreactor 200 can be sealed to the inlet of the microfluidic chip 100, thus avoiding sealing failure due to material fatigue or thermal expansion of the valve needle 310.

[0083] In one possible implementation, an etching element is also included, which is used to etch the surface of the microfluidic chip 100 to form micro-reaction channels for receiving experimental media.

[0084] Understandably, the etching components can be used to etch corresponding micro-reaction channels in the microfluidic chip 100 according to the actual geological structure. The inlet and outlet of the etched microfluidic chip 100 are connected to the valve needle 310 of the delivery structure 300 so as to control the opening and closing of the microfluidic chip 100 through the valve needle 310 to realize the injection and discharge of the experimental medium.

[0085] Secondly, this application provides a microfluidic experimental method with low residual volume, employing the low residual volume microfluidic experimental apparatus as provided in the first aspect. The low residual volume microfluidic experimental apparatus includes a microfluidic chip 100, a microreactor 200, and a delivery structure 300. The delivery structure 300 includes a valve needle 310, a delivery line 320, and a bypass line 330. The experimental method includes the following steps:

[0086] The microfluidic chip 100 is installed inside the microreactor 200. The valve needle 310 is opened, the delivery line 320 is opened, and the bypass line 330 is closed. The first experimental medium is delivered into the microfluidic chip 100 through the delivery line 320.

[0087] The valve needle 310 is closed, the inlet of the microfluidic chip 100 is sealed, the bypass line 330 is opened, the delivery line 320 is connected to the bypass line 330, the second experimental medium is delivered into the delivery line 320, and the first and second experimental media in the delivery line 320 are discharged through the bypass line 330 until the delivery line 320 is full of the second experimental medium.

[0088] Open valve needle 310 and close bypass line 330. The second experimental medium is delivered into microfluidic chip 100 via delivery line 320.

[0089] Understandably, the low residual volume microfluidic experimental device achieves a closed-loop operation effect of "medium delivery - pipeline cleaning and replacement - secondary delivery" by controlling the coordinated switching of the valve needle 310 and the bypass line 330. This enables precise alternating delivery of two or more experimental media without cross-mixing, ensuring the purity and data accuracy of the microfluidic experiment.

[0090] Specifically, when the first experimental medium is being delivered, the valve needle 310 can be opened to connect the delivery line 320 with the inlet of the microfluidic chip 100, thereby delivering the first experimental medium into the microfluidic chip 100.

[0091] When switching to deliver the second experimental medium, valve needle 310 can be closed to seal the inlet of microfluidic chip 100. This not only prevents the first experimental medium remaining in delivery line 320 from flowing back into microfluidic chip 100, but also prevents the experimental medium in microfluidic chip 100 from flowing back into delivery line 320. At the same time, bypass line 330 is opened to connect delivery line 320 and bypass line 330, and the second experimental medium is injected. With its driving force, the first experimental medium remaining in delivery line 320 is completely pushed into bypass line 330 and discharged.

[0092] After the delivery line 320 is filled with the second experimental medium, open the valve needle 310, close the bypass line 330, and then deliver the second experimental medium to the microfluidic chip 100.

[0093] This setup eliminates the possibility of pre-mixing the two experimental media, ensuring the purity of the experimental media entering the microfluidic chip 100 each time. Furthermore, the entire process requires no additional cleaning solution; the second experimental media itself cleans the delivery line 320. After cleaning, the valve needle 310 can be opened to directly deliver the second experimental media into the microfluidic chip 100, shortening the experimental media switching delivery time and facilitating continuous reactions.

[0094] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A microfluidic experimental device with low residual volume, characterized in that, include: Microfluidic chip (100); Microreactor (200), wherein the microfluidic chip (100) is installed inside the microreactor (200); The delivery structure (300) includes a valve needle (310), a delivery line (320), and a bypass line (330). The valve needle (310) is inserted into the microreactor (200) and is sealed to the inlet of the microfluidic chip (100). The ports of the delivery line (320) and the bypass line (330) are both connected to the valve needle (310). The delivery line (320) is used to deliver experimental media into the microfluidic chip (100). The delivery structure (300) is configured such that when the valve needle (310) is open, the delivery line (320) is connected to the microfluidic chip (100); when the valve needle (310) is closed, the inlet of the microfluidic chip (100) is sealed, and the delivery line (320) is connected to the bypass line (330) to discharge the experimental medium in the delivery line (320); The microreactor (200) is used to heat and pressurize the experimental medium inside the microfluidic chip (100); The valve needle (310) includes a valve needle body (311) and a valve handle (312). The valve needle body (311) is inserted into the microreactor (200), and the end of the valve needle body (311) has a conical sealing surface (3111). The inlet of the microfluidic chip (100) is provided with a conical hole adapted to the end of the valve needle body (311). The conical sealing surface (3111) is hard-sealed to the inlet of the microfluidic chip (100). The valve handle (312) is connected to the valve needle body (311), and the valve handle (312) is located outside the microreactor (200); The valve needle body (311) has a micro-nano channel (313), and the microfluidic chip (100) has a micro-reaction channel. The central hole at the end of the valve needle body (311) is connected to the micro-reaction channel through the micro-nano channel (313). The micro-reaction channel is connected to the inlet of the microfluidic chip (100), and the diameter of the tapered hole is slightly larger than the diameter of the micro-reaction channel.

2. The microfluidic experimental apparatus with low residual volume according to claim 1, characterized in that, The valve needle (310) also includes an elastic guide (314), which is mounted on the valve needle body (311) and connected to the microreactor (200). The elastic guide (314) is used to limit the offset of the valve needle body (311).

3. The microfluidic experimental apparatus with low residual volume according to claim 1, characterized in that, It also includes a detector (400) connected to the bypass line (330), the detector (400) being used to detect whether the experimental medium remaining in the delivery line (320) is discharged through the bypass line (330).

4. The microfluidic experimental apparatus with low residual volume according to claim 3, characterized in that, The detector (400) is a flow meter or a spectrometer.

5. The microfluidic experimental apparatus with low residual volume according to any one of claims 1-4, characterized in that, It also includes a controller (500), and the delivery structure (300) is provided in at least two sets. The valve needle (310) of the delivery structure (300) is connected to the inlet and outlet of the microfluidic chip (100). Each set of the delivery structure (300) is electrically connected to the controller (500). The controller (500) is used to control the valve needle (310) to open or close the inlet and outlet of the microfluidic chip (100).

6. The microfluidic experimental apparatus with low residual volume according to any one of claims 1-4, characterized in that, The valve needle (310) is a steel valve needle.

7. The microfluidic experimental apparatus with low residual volume according to claim 1, characterized in that, It also includes an etching element for etching the surface of the microfluidic chip (100) to form micro-reaction channels for receiving the experimental medium.

8. A microfluidic experimental method with low residual volume, characterized in that, Using the low residual volume microfluidic experimental apparatus as described in any one of claims 1-7, the low residual volume microfluidic experimental apparatus includes a microfluidic chip (100), a microreactor (200), and a delivery structure (300), the delivery structure (300) including a valve needle (310), a delivery line (320), and a bypass line (330), the method includes the following steps: The microfluidic chip (100) is installed inside the microreactor (200), the valve needle (310) is opened, the delivery line (320) is opened, the bypass line (330) is closed, and the first experimental medium is delivered into the microfluidic chip (100) through the delivery line (320). The valve needle (310) is closed, the inlet of the microfluidic chip (100) is sealed, the bypass line (330) is opened, the delivery line (320) is connected to the bypass line (330), the second experimental medium is delivered into the delivery line (320), the first experimental medium and the second experimental medium in the delivery line (320) are discharged through the bypass line (330) until the first experimental medium is emptied from the delivery line (320) and the second experimental medium is filled. Open the valve needle (310) and close the bypass line (330), and the second experimental medium is delivered into the microfluidic chip (100) through the delivery line (320).

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