Exhaust treatment structure, microfluidic chip and microfluidic system
By introducing an exhaust treatment structure into a microfluidic chip and using a magnetic bead switch to control liquid flow, the problem of gas removal from the fluid was solved, improving fluid control accuracy and experimental reliability, and achieving fluid stability and reliability of experimental results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- BEIJING YUSHENG ZHIYUAN TECHNOLOGY CO LTD
- Filing Date
- 2025-07-03
- Publication Date
- 2026-06-09
AI Technical Summary
Existing technologies struggle to effectively remove gas from fluids within microfluidic chips, leading to unstable fluid control, low experimental accuracy, and poor reliability, particularly impacting experimental results in high-precision biomedical and chemical analyses.
An exhaust treatment structure is adopted, including a liquid inlet, a liquid outlet, a flow channel, and a drip chamber cavity. The liquid flow is controlled by a magnetic bead switch, and the gas is automatically discharged through the drip chamber cavity. The structure is simple and low in cost.
This technology enables the effective removal of gas from fluids, ensuring fluid stability and experimental reliability, and improving the fluid control accuracy and experimental repeatability of microfluidic chips.
Smart Images
Figure CN224331568U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of microfluidics, and in particular to an exhaust treatment structure, a microfluidic chip, and a microfluidic system. Background Technology
[0002] Microfluidics is a technology that uses microchannels to process and manipulate tiny fluids. It can integrate basic units such as sample preparation, reaction, separation, and detection in fields such as biology, chemistry, and medicine onto a micron-scale microfluidic disk, and automatically complete the entire analysis process through a microfluidic analyzer. It has a wide range of applications in the field of in vitro diagnostics.
[0003] Microfluidic chips are a crucial component of microfluidic technology. In microfluidic chips, the fluids flowing into them (such as culture media) should be kept free of gas (or air bubbles). For example, two reasons are given, and there are certainly more: On a physical level, a gas-free fluid ensures the stability of the microchannels. Because the channels in a chip are only on the micrometer scale, air bubbles can easily form "gas embolisms," clogging the channels or disrupting laminar flow, leading to uneven fluid distribution and affecting the precision of fluid control within the chip. On a biochemical level, a gas-free fluid ensures experimental accuracy and reliability. For example, in some cell-related experiments (such as single-cell studies and organ-on-a-chip culture), the shear force from bursting air bubbles can damage cells, and the space they occupy can lead to cell hypoxia or nutrient deficiency, affecting cell viability and experimental reproducibility. In summary, air bubbles have a significant negative impact on the fluid control, experimental system stability, and detection accuracy of microfluidic chips. Therefore, in high-precision biomedical and chemical analysis applications, it is essential to strictly eliminate gas from the fluid to ensure the reliability and reproducibility of experiments.
[0004] Currently, the common techniques for removing gas from fluids are degassing and filtration, such as vacuum degassing, heating degassing, and microporous membrane filtration. Given the importance of removing gas from fluids, this application provides another technical method for doing so. Utility Model Content
[0005] Therefore, this application provides an exhaust treatment structure, a microfluidic chip, and a microfluidic system, providing another technical means to remove gas from fluids, and the structure is simple and the cost is low.
[0006] In a first aspect, this application provides an exhaust treatment structure, including a liquid inlet, a first liquid outlet, and a second liquid outlet; the liquid inlet is used to connect to an external liquid source, the first liquid outlet is used to connect to a microfluidic chip, and the second liquid outlet is used to connect to a waste liquid tank.
[0007] The exhaust treatment structure has a first flow channel, a second flow channel, a third flow channel, a fourth flow channel, and a drip chamber cavity. The liquid inlet is connected to the top of the drip chamber cavity through the first flow channel. The second flow channel is connected to the bottom of the drip chamber cavity at one end and to the first liquid outlet through the third flow channel and also to the second liquid outlet through the fourth flow channel. A first switch is provided on the third flow channel, and a second switch is provided on the fourth flow channel.
[0008] When the external liquid source injects liquid, both the first switch and the second switch are in the closed state. When a preset volume of liquid accumulates in the drip chamber cavity, the second switch is opened. When the liquid in the drip chamber cavity forms a stable liquid surface, the second switch is closed and the first switch is opened.
[0009] In some embodiments, the first switch and / or the second switch are both bead switches;
[0010] The third and fourth flow channels are both divided into a pre-stage flow channel, a cylindrical cavity, and a post-stage flow channel, which flow sequentially according to the flow direction. The radius of the cylindrical cavity is larger than the radius of the pre-stage flow channel and the radius of the post-stage flow channel. The connection between the pre-stage flow channel and the cylindrical cavity is located on the cavity wall of the cylindrical cavity, and the connection between the post-stage flow channel and the cylindrical cavity is located in the central region of the bottom surface of the cylindrical cavity.
[0011] The magnetic bead switch includes a controllable magnet, a permanent magnet, a ball, and a first rubber ring; the controllable magnet and the permanent magnet are both embedded in the exhaust treatment structure and are located on the top and bottom of the cylindrical cavity, respectively; the radius of the first rubber ring and the radius of the ball are adapted to the radius of the cylindrical cavity, the first rubber ring is located on the bottom surface of the cylindrical cavity, and the ball is disposed in the cylindrical cavity and located above the first rubber ring;
[0012] When the controllable magnet is not magnetic, the ball is attracted by the permanent magnet and presses against the first rubber ring to close the flow channel; when the controllable magnet is magnetic, the ball moves upward under the attraction of the controllable magnet to open the flow channel, wherein the magnetic force generated by the controllable magnet is greater than the magnetic force of the permanent magnet.
[0013] In some embodiments, the connection between the pre-stage flow channel and the cylindrical cavity is below the horizontal plane of the center of the bead.
[0014] In some embodiments, the lower surface of the exhaust treatment structure is provided with a connecting magnet groove, and the exhaust treatment structure further includes a connecting magnet disposed in the connecting magnet groove;
[0015] The connecting magnet is used to attach to the substrate of the microfluidic chip to fix the position of the exhaust treatment structure on the substrate.
[0016] In some embodiments, the bottom of the exhaust treatment structure is provided with two inwardly recessed connecting notches, and both the waste liquid pool and the microfluidic chip are provided with connecting protrusions whose shape is adapted to the connecting notches.
[0017] The upper surface of the connecting boss is provided with a first rubber ring hole formed by inward indentation, and the surface of the connecting recess facing the substrate is provided with a second rubber ring hole formed by inward indentation.
[0018] The first liquid outlet and the second liquid outlet are both located in the central area of the corresponding second rubber ring hole, and the liquid inlet of the waste liquid pool and the liquid inlet of the microfluidic chip are both located in the central area of the corresponding first rubber ring hole.
[0019] A second rubber ring is provided inside the first rubber ring hole. The size of the second rubber ring is adapted to the first rubber ring hole, and the sum of the depth of the first rubber ring hole and the depth of the second rubber ring hole is adapted to the thickness of the second rubber ring.
[0020] The second rubber ring is used to form a seal when the connecting recess abuts against the connecting boss.
[0021] In some embodiments, the upper surface of the connecting boss is provided with a positioning post, and the surface of the connecting recess facing the substrate is provided with a positioning hole adapted to the positioning post.
[0022] In some embodiments, the number of positioning posts is two, and they are symmetrically arranged according to the first rubber ring hole.
[0023] In some embodiments, the bottom of the drip chamber is funnel-shaped.
[0024] Secondly, this application provides a microfluidic chip including an exhaust treatment structure as described in any of the first aspects.
[0025] Thirdly, this application provides a microfluidic system, including the microfluidic chip as described in the second aspect.
[0026] Based on the above technical solution, it can be seen that this application achieves the technical purpose of venting through the cavity of the drip pot, providing another technical means to remove gas from the fluid, and the structure is simple and the cost is low. Attached Figure Description
[0027] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0028] Figure 1 This is a schematic diagram of the exhaust treatment structure in an embodiment of this application from one perspective;
[0029] Figure 2 This is a schematic diagram of the exhaust treatment structure in an embodiment of this application from another perspective;
[0030] Figure 3 This is a schematic diagram of the internal flow channel of the exhaust treatment structure in the embodiments of this application;
[0031] Figure 4 This is a schematic diagram showing the connection relationship of the flow channels in the embodiments of this application;
[0032] Figure 5 for Figure 1 Enlarged view of point A in the middle;
[0033] Figure 6 To be Figure 5 A schematic diagram of the structure of the second rubber ring after disassembly.
[0034] Figure 7 for Figure 2 Enlarged view of point B in the middle;
[0035] Figure 8 for Figure 2 Enlarged view of point C in the middle;
[0036] Figure 9 When the bead switch is closed Figure 1 XX cross-sectional view in the middle;
[0037] Figure 10 When the bead switch is turned on Figure 1 XX cross-sectional view in the middle;
[0038] Figure 11 This is an exemplary cross-sectional view of the connecting boss and the connecting recess when they abut together. Detailed Implementation
[0039] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0040] It should be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.
[0041] It should also be understood that the terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, or the above-mentioned drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence, and should not be construed as indicating or implying their relative importance or implicitly indicating the number of technical features indicated.
[0042] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.
[0043] This application provides an exhaust treatment structure 100, which can be applied to a microfluidic system. Exemplarily, the microfluidic system may include a microfluidic chip and a waste liquid tank, and may also include other components, such as a control system, a liquid source (e.g., a culture medium liquid source), etc. Exemplarily, the microfluidic chip may be an organoid high-throughput culture chip, a cell high-throughput culture chip, an organoid interaction chip, a cell interaction chip, an organoid drug screening chip, a cell drug screening chip, a DNA information storage / extraction chip, etc. Furthermore, the microfluidic chip may include a substrate, and the modules in the microfluidic chip are disposed on the substrate.
[0044] like Figure 1-11 As shown, the exhaust treatment structure 100 includes a liquid inlet 110, a first liquid outlet 120, and a second liquid outlet 130. The liquid inlet 110 is used to connect to an external liquid source, the first liquid outlet 120 is used to connect to a microfluidic chip, and the second liquid outlet 130 is used to connect to a waste liquid tank. That is, the exhaust treatment structure 100 has a one-inlet, two-outlet structure.
[0045] like Figure 3 and Figure 4 As shown, the exhaust treatment structure 100 has a first flow channel 141, a second flow channel 142, a third flow channel 143, a fourth flow channel 144, and a drip chamber cavity 145.
[0046] In this embodiment, the inlet 110 is connected to the top of the drip chamber 145 via a first flow channel 141; one end of the second flow channel 142 is connected to the bottom of the drip chamber 145, and the other end of the second flow channel 142 is connected to the first outlet 120 via a third flow channel 143. Furthermore, the other end of the second flow channel 142 is also connected to the second outlet 130 via a fourth flow channel 144. That is, external liquid enters the drip chamber 145 and then flows from the drip chamber 145 to the microfluidic chip or waste liquid pool. Additionally, a first switch 146 is provided on the third flow channel 143, and a second switch 147 is provided on the fourth flow channel; that is, the switches control whether liquid is allowed to flow through the channels. Exemplarily, the bottom of the drip chamber 145 is funnel-shaped.
[0047] Therefore, when liquid is injected from an external liquid source, both the first switch 146 and the second switch 147 are in the closed state. When a preset volume of liquid accumulates in the drip chamber 145, the second switch 147 is opened. When a stable liquid surface is formed in the drip chamber, the second switch 147 is closed and the first switch 146 is opened.
[0048] It should be noted that drip chambers are commonly used in human infusion applications. The liquid flowing from a drip chamber is bubble-free because the structure of the drip chamber and the pressure balance suppress bubble formation. Since drip chambers are existing technology, their working principle will be briefly explained here. By controlling the liquid level in the drip chamber, for example, to half full, gravity and the pressure balance at the vent ensure that the liquid flows down at a uniform speed. At the same time, the surface tension of the liquid at the drip chamber outlet forms a "film" that prevents air from entering the outlet tube above the drip chamber, ensuring a continuous, bubble-free flow of liquid. In view of this, the embodiments of this application utilize the drip chamber structure to achieve the technical purpose of venting.
[0049] Therefore, when liquid is injected from an external liquid source, both the first switch 146 and the second switch 147 are closed, allowing liquid to accumulate in the dripper cavity 145. Once the liquid in the dripper cavity 145 has accumulated to a certain amount, such as about half full, the second switch 147 opens, and the liquid flows through the second flow channel 142 and the fourth flow channel 144 to the waste liquid pool. At this point, a pressure balance is established, and the liquid level may change. It can be understood that the liquid flowing out of the dripper cavity 145 during this process is not necessarily bubble-free, and therefore not necessarily usable; hence, the liquid flows to the waste liquid pool. Once pressure equilibrium is established, the liquid level in the dripper cavity 145 remains essentially constant. At this point, the liquid flowing out of the dripper cavity 145 is no longer bubble-free. Therefore, the second switch 147 can be closed while the first switch 146 is opened. The liquid in the dripper cavity 145 then flows through the second flow channel 142 and the third flow channel 143 to the microfluidic chip. It can be understood that the liquid flowing into the microfluidic chip is now bubble-free. Thus, this embodiment of the application achieves the technical objective of venting gas through the dripper cavity 145, providing another technical means to remove gas from fluids. Furthermore, it has a simple structure and low cost.
[0050] It should also be noted that the liquid entering the exhaust treatment structure 100 usually contains air bubbles, so it is not necessary to provide an air intake structure for the dripper cavity 145. However, by way of example, an air intake structure may be provided for the dripper cavity 145, for example, by providing a vent hole at the top of the dripper cavity 145 that connects the dripper cavity 145 to the outside.
[0051] In some embodiments, the first switch 146 and / or the second switch 147 can both be bead switches, that is, one can be a bead switch, or both can be bead switches. It should be noted that in this embodiment, the bead switch at the first switch 146 is used as an example for illustration.
[0052] like Figure 9 and Figure 10 As shown, the third and fourth flow channels are divided into a pre-flow channel 210, a cylindrical cavity 220, and a post-flow channel 230, flowing sequentially. The radius of the cylindrical cavity 220 is larger than the radius of both the pre-flow channel 210 and the post-flow channel 230. Furthermore, the connection between the pre-flow channel 210 and the cylindrical cavity 220 is located on the cavity wall of the cylindrical cavity 220, and the connection between the post-flow channel 230 and the cylindrical cavity 220 is located in the central region of the bottom surface of the cylindrical cavity 220. This structural arrangement is primarily for the implementation of a magnetic bead switch. Therefore, the magnetic bead switch includes a controllable magnet 240, a permanent magnet 250, a ball bead 260, and a first rubber ring 270.
[0053] Both the controllable magnet 240 and the permanent magnet 250 are embedded within the exhaust treatment structure 100, and are located above and below the cylindrical cavity 220, respectively. Exemplarily, the controllable magnet 240, the permanent magnet 250, and the cylindrical cavity 220 can be coaxially arranged. It should be noted that this embodiment does not limit the way the controllable magnet 240 generates magnetic force. For example, a current coil may be provided inside the controllable magnet 240 near the cylindrical cavity 220. When the current coil is energized, it generates magnetic force; when de-energized, it loses its magnetic force. The permanent magnet 250 is an object that always possesses magnetism under normal circumstances.
[0054] The radii of the first rubber ring 270 and the ball 260 are both adapted to the radius of the cylindrical cavity 220. The first rubber ring 270 is located on the bottom surface of the cylindrical cavity 220, and the ball 260 is disposed inside the cylindrical cavity 220 and above the first rubber ring 270. This structural arrangement is mainly for the reliability of the magnetic bead switch's off function. For example, since the ball 260 and the first rubber ring 270 are disposed inside the cylindrical cavity 220, they will come into contact with liquid during application. Therefore, the ball 260 and the first rubber ring 270 can be made of corrosion-resistant materials; for example, the ball 260 can be a steel ball, and the first rubber ring 270 can be a rubber ring. Furthermore, the shape of the first rubber ring 270 can be referenced... Figure 6 The second rubber ring is 162.
[0055] Based on this, such as Figure 9 As shown, when the controllable magnet 240 is not magnetic, the ball 260, under the attraction of the permanent magnet 250, presses against the first rubber ring 270 to close the flow channel. Specifically, when the controllable magnet 240 is not magnetic, the ball 260 will tend to move downwards under the attraction of the permanent magnet 250. At the same time, since the ball 260, the first rubber ring 270, and the cylindrical cavity 220 are compatible in shape, the ball 260 will press against the first rubber ring 270 to form a seal, thus preventing liquid from passing through.
[0056] like Figure 10As shown, when the controllable magnet 240 generates magnetism, and the magnetic force generated by the controllable magnet 240 is greater than the magnetic force of the permanent magnet 250, the ball 260 moves upward under the attraction of the controllable magnet 240. For example, the ball 260 moves upward until it abuts other components to open the flow channel. Specifically, when the controllable magnet 240 generates magnetism, its magnetic force is greater than that of the permanent magnet 250. Of course, the magnetic force of the controllable magnet 240 is greater than the magnetic force of the permanent magnet 250 plus the weight of the ball 260, but because it is a miniature device, the weight of the ball 260 can be ignored in this scenario. Therefore, the ball 260 will move upward under the attraction of the controllable magnet 240 and will no longer press against the first rubber ring 270, at which point the liquid can flow normally. For example, the magnetic force generated by the controllable magnet 240 can be twice that of the permanent magnet 250, which makes the control more agile, the response faster, and the latency lower.
[0057] Therefore, it can be seen that the magnetic bead switch in the embodiments of this application has a simple structure, small size, and is more conducive to miniaturization, that is, more conducive to improving integration.
[0058] In some embodiments, such as Figure 9 and Figure 10 As shown, the connection point between the pre-stage flow channel 210 and the cylindrical cavity 220 is lower than the horizontal plane of the center of the ball 260; that is, this connection point is higher than the first rubber ring 270, but lower than the horizontal plane including the center of the ball 260. Thus, in... Figure 10 When the switch is in the open state, the liquid flows very smoothly and will not flow into the space above the ball 260. Therefore, there is basically no liquid accumulation. In other words, the magnetic bead switch in this embodiment can be said to be a switch with zero dead volume.
[0059] In some embodiments, such as Figure 2 As shown, the lower surface of the exhaust treatment structure 100 has a connecting magnet groove (not shown), and the exhaust treatment structure 100 also includes a connecting magnet 150 located within the connecting magnet groove. The connecting magnet 150 is used to adhere to the substrate of the microfluidic chip to fix the position of the exhaust treatment structure 100 on the substrate. Therefore, this embodiment uses magnetic attraction to fix the exhaust treatment structure 100, making operation more flexible. Exemplarily, the number of connecting magnets 150 can be reasonably set, such as two, four, etc., and they can be arranged symmetrically.
[0060] In some embodiments, such as Figure 2 , Figure 7 and Figure 8As shown, the bottom of the exhaust treatment structure 100 is also provided with two inwardly recessed connecting notches 170. Both the waste liquid tank and the microfluidic chip are provided with connecting protrusions 160 whose shape is adapted to the connecting notches 170. It should be noted that although the connecting protrusions 160 of the waste liquid tank and the microfluidic chip are not shown in the attached figure, they can be used as a reference. Figure 1 , Figure 5 and Figure 6 That is, one connecting notch 170 is used in conjunction with the connecting boss 160 of the waste liquid pool, and the other connecting notch 170 is used in conjunction with the connecting boss 160 of the microfluidic chip.
[0061] The upper surface of the connecting boss 160 has a first inwardly recessed adhesive ring hole 161, and the surface of the connecting recess 170 facing the substrate has a second inwardly recessed adhesive ring hole 171. The first adhesive ring hole 161 and the second adhesive ring hole 171 are compatible. Based on this, the first liquid outlet 120 and the second liquid outlet 130 are both located in the central region of the corresponding second adhesive ring hole 171, and the liquid inlet of the waste liquid pool and the liquid inlet of the microfluidic chip are both located in the central region of the corresponding first adhesive ring hole 161.
[0062] A second rubber ring 162 is disposed within the first rubber ring hole 161, and the size of the second rubber ring 162 is adapted to the first rubber ring hole 161. Please refer to... Figure 11 The sum of the depths of the first rubber ring hole 161 and the second rubber ring hole 171 is adapted to the thickness of the second rubber ring 162. For example, the thickness of the second rubber ring 162 is slightly greater than the sum of the depths of the first rubber ring hole 161 and the second rubber ring hole 171. It should be noted that... Figure 11 The above is merely an example to illustrate the relationship between the depth of the first rubber ring hole 161, the depth of the second rubber ring hole 171, and the thickness of the second rubber ring 162.
[0063] Based on this, such as Figure 11 As shown, the second rubber ring 162 is used to form a seal when the connecting recess 170 of the exhaust treatment structure 100 abuts against the connecting boss 160 in the microfluidic chip or waste liquid pool, so that there will be no leakage when the liquid flows in the exhaust treatment structure 100 and the waste liquid pool or the microfluidic chip.
[0064] As discussed above, the exhaust treatment structure 100 can be fixed using magnetic attraction, making operation more flexible. Based on this, in order to further enhance flexibility, this embodiment of the application allows the exhaust treatment structure 100 to be connected to the waste liquid pool and the microfluidic chip when it is magnetically attracted to the substrate, that is, to connect the inlet and outlet and achieve a seal.
[0065] It is understandable that the process of the exhaust treatment structure 100 adsorbing onto the substrate involves a roughly vertical movement towards the substrate. Therefore, this embodiment of the application provides a pair of snap-fit structures, namely the connecting boss 160 and the connecting recess 170, to facilitate connection.
[0066] Furthermore, in order to achieve a seal between the inlet and outlet of the liquid after the connecting boss 160 and the connecting recess 170 abut against each other, the embodiment of this application adopts the first rubber ring hole 161, the second rubber ring hole 171 and the second rubber ring 162 described above. In this way, when the connecting boss 160 and the connecting recess 170 abut against each other, they will form a tight pressure on the second rubber ring 162, thereby achieving the technical purpose of sealing.
[0067] In some embodiments, the upper surface of the connecting boss 160 is provided with a positioning post (not shown), and the surface of the connecting recess 170 facing the substrate is provided with a positioning hole adapted to the positioning post 163. This facilitates the connection between the exhaust treatment structure 100 and the waste liquid pool and the microfluidic chip in this embodiment. Exemplarily, there are two positioning posts, which can be symmetrically arranged according to the first rubber ring hole 161. Correspondingly, there are also two positioning holes, which are symmetrically arranged according to the second rubber ring hole 171.
[0068] This application also provides a microfluidic chip and a microfluidic system. The microfluidic chip includes the exhaust treatment structure 100 as described in any of the above embodiments, and the microfluidic system includes the microfluidic chip. For specific implementation details of the microfluidic chip and microfluidic system, please refer to the preceding discussion; these details will not be repeated here.
[0069] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. An exhaust treatment structure, characterized in that, It includes an inlet, a first outlet, and a second outlet; the inlet is used to connect to an external liquid source, the first outlet is used to connect to a microfluidic chip, and the second outlet is used to connect to a waste liquid tank. The exhaust treatment structure has a first flow channel, a second flow channel, a third flow channel, a fourth flow channel, and a drip chamber cavity. The liquid inlet is connected to the top of the drip chamber cavity through the first flow channel. The second flow channel is connected to the bottom of the drip chamber cavity at one end and to the first liquid outlet through the third flow channel and also to the second liquid outlet through the fourth flow channel. A first switch is provided on the third flow channel, and a second switch is provided on the fourth flow channel. When the external liquid source injects liquid, both the first switch and the second switch are in the closed state. When a preset volume of liquid accumulates in the drip chamber cavity, the second switch is opened. When the liquid in the drip chamber cavity forms a stable liquid surface, the second switch is closed and the first switch is opened.
2. The exhaust treatment structure according to claim 1, characterized in that, The first switch and / or the second switch are both bead switches; The third and fourth flow channels are both divided into a pre-stage flow channel, a cylindrical cavity, and a post-stage flow channel, which flow sequentially according to the flow direction. The radius of the cylindrical cavity is larger than the radius of the pre-stage flow channel and the radius of the post-stage flow channel. The connection between the pre-stage flow channel and the cylindrical cavity is located on the cavity wall of the cylindrical cavity, and the connection between the post-stage flow channel and the cylindrical cavity is located in the central region of the bottom surface of the cylindrical cavity. The magnetic bead switch includes a controllable magnet, a permanent magnet, a ball, and a first rubber ring; the controllable magnet and the permanent magnet are both embedded in the exhaust treatment structure and are located on the top and bottom of the cylindrical cavity, respectively; the radius of the first rubber ring and the radius of the ball are adapted to the radius of the cylindrical cavity, the first rubber ring is located on the bottom surface of the cylindrical cavity, and the ball is disposed in the cylindrical cavity and located above the first rubber ring; When the controllable magnet is not magnetic, the ball is attracted by the permanent magnet and presses against the first rubber ring to close the flow channel; when the controllable magnet is magnetic, the ball moves upward under the attraction of the controllable magnet to open the flow channel, wherein the magnetic force generated by the controllable magnet is greater than the magnetic force of the permanent magnet.
3. The exhaust treatment structure according to claim 2, characterized in that, The connection point between the pre-stage flow channel and the cylindrical cavity is below the horizontal plane of the center of the bead.
4. The exhaust treatment structure according to claim 1, characterized in that, The lower surface of the exhaust treatment structure is provided with a connecting magnet groove, and the exhaust treatment structure also includes a connecting magnet disposed in the connecting magnet groove; The connecting magnet is used to attach to the substrate of the microfluidic chip to fix the position of the exhaust treatment structure on the substrate.
5. The exhaust treatment structure according to claim 4, characterized in that, The bottom of the exhaust treatment structure is provided with two inwardly recessed connecting notches, and both the waste liquid pool and the microfluidic chip are provided with connecting protrusions whose shape is adapted to the connecting notches. The upper surface of the connecting boss is provided with a first rubber ring hole formed by inward indentation, and the surface of the connecting recess facing the substrate is provided with a second rubber ring hole formed by inward indentation. The first liquid outlet and the second liquid outlet are both located in the central area of the corresponding second rubber ring hole, and the liquid inlet of the waste liquid pool and the liquid inlet of the microfluidic chip are both located in the central area of the corresponding first rubber ring hole. A second rubber ring is provided inside the first rubber ring hole. The size of the second rubber ring is adapted to the first rubber ring hole, and the sum of the depth of the first rubber ring hole and the depth of the second rubber ring hole is adapted to the thickness of the second rubber ring. The second rubber ring is used to form a seal when the connecting recess abuts against the connecting boss.
6. The exhaust treatment structure according to claim 5, characterized in that, The upper surface of the connecting boss is provided with a positioning post, and the surface of the connecting recess facing the substrate is provided with a positioning hole that matches the positioning post.
7. The exhaust treatment structure according to claim 6, characterized in that, The number of positioning pins is two, and they are symmetrically arranged according to the first rubber ring hole.
8. The exhaust treatment structure according to claim 1, characterized in that, The bottom of the drip pot cavity is funnel-shaped.
9. A microfluidic chip, characterized in that, Includes the exhaust treatment structure as described in any one of claims 1-8.
10. A microfluidic system, characterized in that, Including the microfluidic chip as described in claim 9.