Fluid device

Abstract

The present disclosure relates to a fluid device that efficiently removes or manages air bubbles in a flow path using a centrifugal force. The accumulation of air bubbles is prevented by providing a flow path equipped with an inlet and an outlet for fluid, and adjusting the distribution of an effective potential in a centrifugal force field. In some embodiments, a bubble trap for trapping air bubbles is provided in the flow path. Furthermore, the ends of the fluid-inlet flow path and the fluid-outlet flow path are designed with the same effective potential, resulting in a structure such that the fluid stands still under the centrifugal force field. This configuration improves the measurement accuracy and operation efficiency of the fluid device.

Description

Fluid device

[0001] This disclosure relates to a device for manipulating or controlling fluids.

[0002] Fluid devices are widely used in fields such as chemical analysis, medical diagnosis, and biotechnology, and are used to accurately control the movement, distribution, and mixing of fluids. In such devices, it may be desirable for the liquid to flow stably within the flow path.

[0003] However, bubbles may occur within the flow path. The causes of bubble generation include fluid properties, flow path shape, pressure changes, and environmental conditions. Conventional countermeasures for bubbles include methods of suppressing turbulent flow using a wide cross-section flow path, methods of using hydrophobic or hydrophilic materials on the inner wall of the flow path, methods of removing bubbles using centrifugal force and vacuum, methods of using defoaming agents, and the like.

[0004] One objective of this disclosure is to provide a configuration for effectively removing bubbles within the flow path, or managing or utilizing bubbles as control elements, in a fluid device that utilizes centrifugal force, for example.

[0005] One aspect of this disclosure includes a configuration for feeding a fluid using centrifugal force and adjusting the effective potential of the centrifugal force field in a flow path section in a fluid device having a flow path with a fluid inlet and an outlet. Specifically, in some embodiments, the balance between the propulsive force and the drag force acting on the bubbles is controlled by adjusting the geometric shape (such as inclination, spiral shape, etc.) and cross-sectional area of the flow path. Also, in some embodiments, a bubble trap is provided in the flow path section to guide and capture the bubbles at a specific position. Furthermore, in some embodiments, a valve mechanism is provided that opens, closes, or switches the flow path using the interfacial tension of the bubbles or the specific gravity difference between the gas and the liquid.

[0006] According to at least one embodiment of this disclosure, it may be possible to suppress the accumulation of bubbles in the flow path by appropriately adjusting the effective potential of the centrifugal force field. Furthermore, in embodiments in which a bubble trap is installed, it becomes easier to guide bubbles to specific locations and improve the overall operating efficiency of the fluid device. In addition, in embodiments in which bubbles are used as passive or active control factors, complex fluid delivery sequences can be realized without the use of external actuators.

[0007] Further aspects and advantages of the present disclosure will be readily apparent to those skilled in the art from the following detailed description, which shows and describes only exemplary embodiments of the present disclosure. As will be understood, other different embodiments are possible, and some of their details can be modified in various obvious ways without departing from the present disclosure. Accordingly, the drawings and description should be considered illustrative and not limiting in nature.

[0008] This section schematically illustrates comparative examples illustrating the behavior of bubbles in a fluid device, with (A) showing the state before centrifugal force is applied and (B) showing the state after centrifugal force is applied. This section schematically shows the internal structure of a fluid device having a straight channel arranged at an inclination with respect to the centrifugal force direction, according to one embodiment (Embodiment 1) of this disclosure. This diagram schematically shows the configuration of a constant-thrust spiral channel and the mechanical relationships within the channel, according to one embodiment (Embodiment 2) of this disclosure. This is an enlarged plan view showing the detailed structure of a detection chamber equipped with a sample introduction section, a throttling section, and a sensor, according to one embodiment (Embodiment 5) of this disclosure. This section schematically shows the structure of a fluid device having a bubble trap positioned at the effective potential maximum, according to one embodiment (Embodiment 7) of this disclosure. This section schematically shows a fluid stabilization structure (U-shaped channel) according to another embodiment (Embodiment 8) of this disclosure, configured such that the fluid introduction channel and the fluid discharge channel have equal effective potential under centrifugal force. This is a schematic diagram showing the operation sequence of a gas-liquid displacement valve mechanism according to one embodiment (Embodiment 9) of the present disclosure, where (a) shows the introduction of liquid and flow to the trap side (left direction), (b) shows the formation of a bubble stopper by gas-liquid displacement, and (c) shows the flow to the discharge side (right direction) by switching the flow path. This is a top view showing examples of the shape of a fluid device according to one embodiment (Embodiment 10) of the present disclosure, where (A) shows a circular disk-shaped fluid device having a plurality of measuring sections, (B) shows a fan-shaped fluid device, and (C) shows an irregularly shaped fluid device formed to fit within a fan-shaped region. Detailed description of the invention

[0009] As used herein, the term "flow channel" generally refers to a path formed for the movement of a fluid. A flow channel includes portions containing fluid inlets and outlets, as well as flow channel sections connecting them. The shape of the flow channel may be linear, curved, or nonlinear.

[0010] In some embodiments, the channel may be configured to perform measurements on the fluid inside it. A sensor may be placed in the channel. The sensor may be an electrochemical sensor. The channel may be an optical channel and configured to measure the optical properties of the fluid inside it. For example, the channel may be an optical channel for measuring the absorbance of the fluid inside it. When the channel is used for sensing, bubbles inside it may make the measurement inaccurate or impossible. Removing bubbles from the channel can ensure that the measurement is performed and improve its accuracy.

[0011] In some embodiments, the fluid introduced into the channel may not contain an antifoaming agent. Antifoaming agents may be introduced to prevent the formation of bubbles in the microfluidic system. However, antifoaming agents can interfere with the detection or measurement of the electrical, optical, chemical, or biological properties of the fluid. The channel and centrifugal force of this disclosure enable sensing that is unaffected or minimally affected by bubbles, even when antifoaming agents are not included.

[0012] As used herein, the term "inertial force field" generally refers to a force field formed by apparent forces or gravity acting as volume forces on a mass. This includes centrifugal force fields associated with rotational motion, acceleration fields associated with linear motion, gravitational fields, and combinations thereof.

[0013] As used herein, the term “centrifugal force field” refers to a type of inertial force field, generally a force field formed by apparent forces generated in rotational motion. In many embodiments of this disclosure, this centrifugal force field influences the movement of fluids and bubbles, and is used as an important factor in determining the direction of bubble movement or accumulation location, particularly through interaction with the geometric shape of the flow path.

[0014] As used herein, the term "effective potential" refers to the combined potential of centrifugal force, gravity, and other forces. The effective potential U(s) is defined as a function of coordinate s along the flow path. It may have local maxima or minimums at specific locations, and its distribution is an important indicator of the fluid and bubble motion.

[0015] The core concept of this disclosure is to configure the geometric shape of the flow path (flow path vector) to have a specific angular relationship with the inertial force field (force vector), and to adjust the cross-sectional area profile of the flow path. This intentionally manipulates the "propulsion component" that contributes to the discharge of bubbles throughout the entire length of the flow path.

[0016] The movement of bubbles is determined by the balance between (1) the thrust due to inertial buoyancy and (2) the drag due to fluid viscosity. In conventional designs, the control of this "drag" was not adequately considered, which sometimes resulted in bubbles becoming stationary due to changes in flow velocity, or conversely, bubbles splitting due to excessive acceleration.

[0017] In some embodiments of this disclosure, the geometric profile of the flow path employs a configuration in which the width (cross-sectional area) of the flow path is varied according to the position. For example, by increasing the width of the flow path, the flow velocity is reduced, decreasing the drag force acting on the bubbles (making buoyancy relatively dominant), thereby promoting bubble coalescence and discharge. Conversely, by reducing the width of the flow path, the flow velocity is locally increased, generating strong momentum (jet flow), which can forcibly replace stagnant fluid. In this way, by simultaneously designing not only the "mechanical gradient (potential)" but also the "hydrodynamic resistance (drag)" through geometric shape, more advanced bubble control and fluid delivery control than conventional methods can be achieved.

[0018] As used herein, the term “coordinates s along the flow path” may be defined as follows: In some embodiments, “coordinates s along the flow path” is defined based on the centerline of the flow path. In this case, the centerline represents the path along which the fluid primarily moves, and the effective potential U(s) is determined based on the position on this centerline. In some other embodiments, “coordinates s along the flow path” is defined based on the inner wall in the direction of centrifugal force within the flow path. In this case, the effective potential U(s) is calculated relative to the position on the inner wall. This definition is suitable for identifying the potential distribution in areas where bubbles are likely to accumulate.

[0019] As used herein, the term "monotonically decreasing" refers to a state in which the effective potential U(s) continuously decreases along the flow path without any local maxima or local increase. This condition is determined by satisfying the following equation: This equation shows that the effective potential gradient is negative or constant, ensuring that no bubbles accumulate within the flow channel. To further emphasize the absence of a maximum value, the following equation may be referenced: This condition indicates that the effective potential is convex, supplementing the characteristics of the potential distribution.

[0020] As used herein, the term "bubble trap" refers to a structure designed to capture or accumulate bubbles within a flow channel. Bubble traps include, but are not limited to, recesses, grooves, and surfaces with hydrophobic coatings. Bubble traps are installed at specific locations within a flow channel and are used to control the flow of bubbles.

[0021] As used herein, the term "specific location" generally refers to a location where a maximum value of the effective potential occurs within the flow path, or a location where bubbles tend to accumulate. This location may be determined by the centrifugal force field or the flow path geometry.

[0022] As used herein, the term “fluid device” generally refers to an apparatus designed for the transfer, processing, or analysis of fluids. Fluid devices include channels, inlets, outlets, and the structures that comprise them.

[0023] In this specification, when the term "passive" is used in relation to a fluid control mechanism, it primarily refers to a method in which the behavior of the fluid is determined by the interaction between the geometric shape of the flow path, surface characteristics, or the physical properties of the fluid (specific gravity, viscosity, interfacial tension, etc.) and a uniform field applied from the outside (centrifugal field, gravitational field, etc.). In contrast, "active" generally refers to a method of manipulating the fluid using local actuators (piezoelectric elements, heaters, electrodes, etc.) embedded within the device.

[0024] Some fluid devices according to certain embodiments of this disclosure employ a "passive" configuration that does not require an external power supply or wiring, while utilizing bubbles and displacement fluid to realize complex fluid delivery sequences (pause, switching, constant flow rate, etc.) that were previously difficult to achieve without active control. Therefore, each embodiment in this specification is not strictly limited to either the passive or active category, and configurations that use external triggers (sudden changes in rotational speed, temperature changes, etc.) as needed are not excluded.

[0025] Reference Example: Bubble Retention Phenomenon Figure 1 schematically shows the configuration of a device that performs rotational motion as an example of a fluid device 100. This figure does not show the entire fluid device 100, but only the sector-shaped portion is extracted and shown for the sake of brevity of explanation.

[0026] The fluid device 100 is configured to rotate about a rotation axis O, and a flow channel 110 is formed inside it. This flow channel 110 is located within a sector-shaped portion, and both ends are located on the equipotential lines 151. A fluid 111 is contained within the flow channel 110. Bubbles 112 are also present within the flow channel 110, and their behavior is affected by the centrifugal force Fc.

[0027] Figure 1(A) schematically shows the state before a centrifugal force Fc is applied to the fluid device 100. In this state, the bubbles 112 are dispersed at arbitrary positions within the flow path 110. A maximum value point A in the effective potential distribution is shown in the figure, and this maximum value point determines the movement of the bubbles after the centrifugal force is applied.

[0028] Figure 1(B) schematically shows the state after a centrifugal force Fc is applied. In this state, the bubbles 112 move due to the influence of the centrifugal force and accumulate at the effective potential maximum point A, where the centrifugal force Fc and the center line of the flow path are perpendicular. If the effective potential maximum point A is located near the center of the flow path 110, the bubbles 112a remain at that position and accumulate without being discharged from the flow path. This phenomenon can degrade the overall performance of the fluid device and adversely affect measurement and analysis.

[0029] Referring to Figure 1, it can be understood that the distribution of effective potential in a rotating fluid device directly affects the movement and accumulation location of bubbles. When a point of maximum effective potential exists within the flow path, it becomes clear that bubbles accumulate at that location and accumulate without being discharged, which presents a problem.

[0030] This figure is presented as a comparative example to illustrate the technical background of this disclosure and aims to clarify the challenges of the current technology. The present invention provides a new configuration to solve these challenges.

[0031] Embodiment 1: Diagram 2 of the inclined linear flow path schematically shows one embodiment of the present disclosure and illustrates the configuration of a fluid device 200 that performs rotational motion. This figure does not show the entire fluid device 200, but only the sector-shaped portion is extracted and shown for the sake of brevity of the explanation.

[0032] The fluid device 200 is configured to rotate about a rotation axis O, and a flow channel 210 is formed inside it. This flow channel 210 is positioned diagonally within a sector-shaped portion, with one end positioned on the first equipotential line 251 and the other end on the second equipotential line 252, which has a higher potential than the first equipotential line 251. Fluid 211 is contained inside the flow channel 210. In addition, multiple bubbles 212 exist inside the flow channel 210, and their behavior is affected by the centrifugal force Fc.

[0033] In Figure 2, the point of maximum effective potential A is located near the exit of the channel rather than in the middle of the channel 210, because there is no point where the centrifugal force Fc and the center line of the channel are perpendicular. With this configuration, the bubbles 212 are affected by the centrifugal force Fc, pass through the channel 210, and are eventually discharged outside the channel beyond the point of maximum potential A.

[0034] The direction of movement of the bubbles 212 in Figure 2 is indicated by the arrows. This movement is controlled by the shape of the flow path 210 and the effective potential distribution under the centrifugal force field. The effective potential maximum point A is located near the flow path outlet, ensuring that bubbles do not remain in the flow path and are efficiently discharged.

[0035] Referring to Figure 2, it can be understood that the design of the effective potential distribution in this embodiment improves the efficiency of bubble removal. This embodiment of the disclosure effectively resolves the problem of bubbles continuing to accumulate in the flow path in conventional devices.

[0036] As shown in Figure 2, in this embodiment, the flow path is linear and extends at a predetermined inclination angle with respect to the direction of centrifugal force (radial direction). This configuration is particularly suitable for applications involving optical measurements such as absorbance and fluorescence measurements.

[0037] In optical measurements, a straight flow path is sometimes preferable to ensure sufficient optical path length or to maintain a linear measurement area. However, in a simple radially straight flow path, the fluid movement due to centrifugal force may become too rapid. Therefore, in this embodiment, the flow path is intentionally inclined from the radial direction to adjust (reduce) the effective centrifugal force component acting on the fluid, thereby achieving appropriate flow velocity control.

[0038] Specifically, the angle between the centerline of the flow path and the radius line passing through a point on that centerline is set to a range of 10 degrees to 80 degrees, more preferably 30 degrees to 60 degrees. This angle range is effective in suppressing excessive flow velocity while ensuring the potential difference (potential energy difference) necessary for fluid delivery.

[0039] Furthermore, by employing such a sloping straight channel, the rate of change in distance from the center of rotation can be made more gradual. This has the advantage of reducing the change in centrifugal force per unit time, making it easier to control the liquid level and reaction time in the detection unit.

[0040] Embodiment 2: Constant Thrust Spiral Flow Path FIG. 3 is a diagram showing a flow path configuration according to a specific embodiment of the present disclosure. In this embodiment, the basic configuration shown in FIG. 2 described above is further optimized, and the flow path is configured in a “constant thrust spiral shape”. This shape is designed to precisely control the behavior of bubbles particularly in optical measurements and electrochemical sensing where high measurement accuracy is required.

[0041] As shown in FIG. 3, on the substrate 300 of the microfluidic device, the flow path 310 extends from the first radius position 351 on the inner peripheral side to the second radius position 352 on the outer peripheral side. In a centrifugal force field, the centrifugal force Fc acting on an object (bubble or fluid) with mass m increases proportionally to the distance (radius) r from the center of rotation O (Fc = mrω^2). Therefore, when the flow path has a simple linear shape and extends in the radial direction, the force acting on the bubble increases acceleratively towards the outer peripheral part (downstream side). This rapid increase in force gives an excessive shear force to the bubble and causes the bubble to split. The generated fine bubbles are difficult to be discharged due to their small buoyancy and adhere to the sensor surface to generate noise.

[0042] To solve this problem, the flow path 310 shown in FIG. 3 is curved such that the inclination angle α of the flow path with respect to the radial direction gradually increases as it goes from the center of rotation towards the outer periphery. The driving force (Fdrive) that pushes the bubble along the flow path is the tangential component of the centrifugal force Fc in the flow path direction, and is represented by the following formula:

[0043] In this embodiment, the shape of the flow path 310 is designed such that in the section from the first radius position 351 to the second radius position 352, the increase in the centrifugal force due to the increase in the radius r is offset by the decrease in cos(α) due to the increase in the angle α. That is, the following relationship holds or is approximately satisfied over the entire length of the flow path: (Here, C is a constant.)

[0044] As shown by arrow 312 in FIG. 3, due to this geometric configuration, the magnitude of the driving force Fdrive is maintained substantially constant from the inner peripheral side (starting point) to the outer peripheral side (ending point). As a result, the bubbles are gently discharged at a constant speed without being overly accelerated. Thereby, the splitting of the bubbles is prevented, and it is possible to effectively avoid scattering on the optical path in optical measurement, a decrease in sensitivity (deterioration of the liquid exchange rate) due to the attachment of minute bubbles to the electrode surface in an electrochemical sensor, and the like.

[0045] Embodiment 3: Logarithmic spiral flow path The curved flow path has a shape that gently curves from the inlet to the outlet. In some embodiments, the center line of the curved flow path may描绘 an arc-shaped, elliptical arc-shaped, or spiral-shaped curve.

[0046] In some embodiments, the curved shape of the curved flow path is based on a logarithmic spiral. Here, the logarithmic spiral refers to a curve in polar coordinate representation where the relationship between the radius r and the angle θ is expressed as r = a · exp(bθ) using constants a and b.

[0047] By making the curved flow path logarithmic spiral in shape, it becomes possible to keep the inflow angle of the fluid constant throughout the entire area from the inlet to the outlet. Thereby, an effect of suppressing the separation of the fluid and the generation of vortices in the curved flow path is obtained. Note that the curved shape is not limited to a logarithmic spiral and may be an Archimedes spiral or a clothoid curve.

[0048] [[ID=(此处原文可能有误,推测为ID=12)]] Embodiment 4: Variable cross-section flow path In some embodiments, the cross-sectional area of the flow path may vary along the longitudinal direction of the flow path. Thereby, it becomes possible to locally control the flow velocity and pressure of the fluid in the flow path. The change in the cross-sectional area is achieved by changing the width, depth, or both of the flow path.

[0049] (1) Widened Flow Channel (Tapered Out) In one embodiment, the cross-sectional area of ​​the flow channel gradually increases from the inlet to the outlet. This configuration has the effect of reducing the fluid velocity and restoring static pressure (diffuser effect). By reducing the flow velocity, it is possible to ensure a longer contact time between the fluid and the flow channel wall (or functional layer placed at the bottom). This is advantageous in general chemical reactions with relatively slow reaction rates, or in applications where a reduction in flow channel resistance is required.

[0050] (2) Tapered Inflow Channel In another embodiment, the cross-sectional area of ​​the flow channel gradually decreases from the inlet to the outlet. This configuration has the effect of accelerating the fluid velocity (nozzle effect). This configuration is particularly useful in applications involving electrochemical measurements or electrochemical reactions.

[0051] Specifically, increasing the flow velocity can reduce the thickness of the diffusion layer near the electrode surface. Thinning the diffusion layer improves the mass transfer rate, thereby increasing the electrochemical response sensitivity or reaction efficiency. Furthermore, the high shear force is expected to suppress the adhesion of bubbles or the accumulation of fouling on the electrode surface.

[0052] Embodiment 5: Structural diagram 4 of the sample introduction and detection section is a plan view of a fluid device according to one embodiment of the present disclosure. The fluid device 400 comprises an introduction channel 410 for receiving a sample (for example, a biological sample such as blood, urine, or saliva) and a detection chamber 401 located downstream thereof.

[0053] The introduction channel 410 is located upstream of the detection chamber 401 with respect to the direction of the centrifugal force Fc. At the upstream end of the introduction channel 410, a wide sample reservoir 411 is provided for spot-applying and temporarily holding the sample (a spot-applying section may be located upstream of it). Along the path downstream from the sample reservoir 411, a constricted section 412 is formed where the cross-sectional area of ​​the channel is locally reduced. This constricted section 412 acts as a valve to prevent unintended outflow of the sample or as a trap to prevent the inclusion of air bubbles by increasing the flow resistance.

[0054] The sample that has passed through the throttling section 412 flows into the detection chamber 401 via the connecting channel 402. Inside the detection chamber 401 is a sensor 403, such as an electrochemical sensor, an optical sensor, or a color-developing reagent pad. As shown in Figure 4, the sensor 403 is positioned in the U-shaped curved section (bottom) of the detection chamber 401, and is configured so that the sample delivered by centrifugal force Fc reliably covers the surface of the sensor 403.

[0055] Furthermore, even if bubbles 405 (not shown, or see Figure 3) are introduced into the sample during the centrifugation process, the bubbles 405 tend to remain on the inner circumference side (connecting channel 402 side) due to buoyancy, thus suppressing their adhesion to the sensor 403 on the outer circumference side. In addition, the connecting channel 402 extends along the direction of the centrifugal force Fc, while the discharge channel after passing through the detection chamber 401 extends in a direction intersecting the centrifugal force Fc. This configuration makes it possible to allow sufficient time for the sample to remain in the sensor 403 portion.

[0056] Embodiment 6: Bubble Control Mechanism The fluid device of this disclosure may have a structure that not only removes bubbles generated or mixed into the flow path, but also actively utilizes them as an element of fluid control. In this embodiment, a passive control mechanism that utilizes the interfacial tension of bubbles will be described.

[0057] (1) Physical trap and valve sequence As shown in Figure 5, a trap section is provided in a part of the flow path (e.g., a branch section, the inner circumference side, etc.) to physically capture air bubbles. The trap section is formed, for example, as a recess provided in the ceiling of the flow path, a chamber in which the width of the flow path is locally widened, or a branching point of the flow path.

[0058] Under the influence of centrifugal force, lighter bubbles move toward the center of rotation (inner circumference) and are held in this trap section. This phenomenon can be used to control the sequence of liquid delivery. For example, while bubbles remain in the trap section, the flow of liquid through that path is blocked (valve function). This delay time can be used to ensure sufficient time for reagent dissolution or to synchronize the mixing timing of multiple reagents.

[0059] Embodiment 7: Bubble Trap to the Effective Potential Maximum Figure 5 is a schematic diagram illustrating one embodiment of the present disclosure and explains the configuration of a rotational fluid device 500. This figure does not show the entire fluid device 500, but only the sector-shaped portion is extracted and shown for the sake of brevity of the explanation.

[0060] The fluid device 500 is configured to rotate about a rotation axis O, and a flow channel 510 is formed inside it. This flow channel 510 is located within a sector-shaped portion, and both ends are located on the equipotential lines 551. It is positioned diagonally within the device plane and contains a fluid 511. Bubbles 512 are also present in the flow channel 510, and their behavior is affected by the centrifugal force Fc.

[0061] The bubbles 512 move based on the distribution of the effective potential under the influence of the centrifugal force Fc, and in particular have the property of gathering at the maximum value point A where the centrifugal force Fc and the center line of the flow path are perpendicular. In this embodiment, the bubble trap 520 is provided at this maximum value point A to efficiently capture the bubbles 512.

[0062] A structure (bubble trap) 520 is positioned in the central part of the flow path 510, perpendicular to the flow path 510 (in the device plane), and an opening 521 is formed at its end on the side of the rotation axis O. This opening 521 functions as an inlet for the fluid 511. It also acts as a vent when bubbles 512 move to the bubble trap 520, and by expelling existing air when fluid is introduced, it provides a mechanism that efficiently guides bubbles into the bubble trap 520.

[0063] The direction of movement of the bubbles 512 shown in Figure 5 is indicated by arrows. This movement is due to the shape of the flow path 510 and the effective potential distribution under the centrifugal force field. By appropriately designing the effective potential distribution, the bubbles 512 are efficiently guided to the bubble trap 520.

[0064] Referring to Figure 5, it can be understood that the adjustment of the effective potential distribution and the flow path design in this embodiment improve the efficiency of bubble removal. This embodiment provides a configuration that efficiently captures bubbles simultaneously with fluid introduction and prevents bubble accumulation in the flow path.

[0065] Embodiment 8: Fluid stabilization structure by equipotential connection Figure 6 schematically shows another embodiment of the present disclosure and illustrates the configuration of a fluid device 600 that performs rotational motion. This figure does not show the entire fluid device 600, but only the sector-shaped portion is extracted and shown for the sake of brevity of the explanation.

[0066] The fluid device 600 is configured to rotate about a central axis O, and a flow channel 610 is formed inside it. This flow channel 610 is arranged in a U shape and contains a fluid 611. In addition, bubbles 612 exist within the flow channel 610, and their behavior is affected by the centrifugal force Fc.

[0067] A vertical structure 620 is positioned in the central part of the flow path 610, perpendicular to the flow path 610 within the device plane, and an opening 621 is formed at its top. This opening 621 functions as an inlet for introducing the fluid 611 into the flow path 610. In this embodiment, the design ensures that existing air generated during fluid introduction is efficiently discharged, thereby enabling the stable arrangement of the fluid 611 within the flow path 610.

[0068] A fluid inlet channel 631 and a fluid outlet channel 632 are connected to both ends of the flow path 610, respectively. These channels are designed so that the fluid 611 in the flow path 610 remains stationary under centrifugal force. Specifically, the ends of the fluid inlet channel 631 and the fluid outlet channel 632 are designed to have the same effective potential, thereby preventing the fluid 611 from moving within the flow path 610. In contrast, if the potentials at both ends are different, the fluid 611 may move within the flow path 610 due to the effect of centrifugal force, potentially causing an unstable state.

[0069] Furthermore, the outer equieffective potential surface 651 and the inner equieffective potential surface 652 surrounding the flow path 610 function as elements that control the movement of the fluid 611 and bubbles 612 within the flow path. This design, based on these equieffective potential surfaces, ensures that the fluid within the flow path 610 remains stationary and that the bubbles 612 are efficiently controlled.

[0070] In this embodiment, the design optimizes the shape of the flow path 610 and the arrangement of the fluid introduction flow path 631 and the fluid discharge flow path 632 to improve the management of bubbles 612. With this configuration, the fluid 611 in the flow path 610 remains stationary, while the bubbles 612 are appropriately moved by centrifugal force Fc and efficiently captured or removed within the flow path 610.

[0071] Embodiment 9: Gas-Liquid Replacement Valve Mechanism Figures 7(a) to (c) are schematic diagrams showing the operation sequence of a gas-liquid replacement valve mechanism 700 that utilizes the difference in specific gravity between gas and liquid in a centrifugal force field (see arrow Fc).

[0072] Figure 7(a) shows the initial waiting state for filling. Due to the rotation of the fluid device, the introduced liquid 721 is supplied from the introduction channel 711 by centrifugal force Fc. At the branching point, the introduced liquid 721 is distributed to the retention channel 712 and the liquid trap channel 713 (arch-shaped channel in the figure). At this time, the liquid component that flows into the retention channel 712 and remains there temporarily is designated as the waiting liquid 722, and the liquid component that fills the liquid trap channel 713 is designated as the replacement liquid 723. Any excess liquid that does not fit into these channels is discharged into the first branch channel 714 (drain channel).

[0073] At this stage, both the displacement valve 731 at the inlet (upper part) of the displacement chamber 740 and the downstream discharge valve 732 are in a closed state. In this embodiment, these valves 731 and 732 are composed of, for example, a destructible sealing member (film, thin film, etc.) that blocks the flow path. Therefore, the captured gas 741 (air, etc.) inside the displacement chamber 740 has nowhere to escape, and the liquid cannot flow into the displacement chamber 740. In order to ensure gas-liquid displacement in a later step, it is preferable that the volume of the displacement chamber 740 be set to be larger than the liquid trap flow path 713 (holding volume of displacement liquid 723).

[0074] Next, in the filling (replacement) process shown in Figure 7(b), the replacement valve 731 is opened (or destroyed). This opening is performed, for example, by using a physical projection member (such as a pin) that can be operated from outside the device to puncture or destroy the sealing member (destructive opening method). The valve opening mechanism is not limited to this, and a heat-meltable wax valve, a laser-irradiated melting valve, etc., may also be used.

[0075] As a result, due to the interaction of centrifugal force Fc and buoyancy, the high-density replacement liquid 723 in the liquid trap channel 713 attempts to flow into the replacement chamber 740 (black arrow), and at the same time, the low-density captured gas 741 that was in the replacement chamber 740 moves into the liquid trap channel 713 (gray arrow). At this time, the replacement liquid 723 in the liquid trap channel 713 near the first branch channel 714 is pushed out in the direction of the first branch channel 714 by the captured gas 741. This driving force causes a rapid exchange of captured gas 741 and replacement liquid 723, and the replacement chamber 740 is filled with replacement liquid 723.

[0076] Next, in the discharge process shown in Figure 7(c), the discharge valve 732 is opened. As a result, the waiting liquid 722 in the retention channel 712 is sent to the second branch channel 715 (main channel) by centrifugal force Fc. At this time, the replacement liquid 723 that has moved into the replacement chamber 740 is retained in the chamber 740 (does not flow out) due to the action of centrifugal force.

[0077] In some embodiments, the fluid device is configured to utilize centrifugal force, in which case the entire device or a part thereof is designed to rotate. For example, the fluid device may be circular in shape, have a rotation axis at its center, and be configured to rotate around this axis. Alternatively, the fluid device may have a circular shape, but only a part of it, and may be formed in a fan shape.

[0078] In some embodiments, the fluid device has a disc shape with multiple measuring sections, and the disc may be divided into multiple sector-shaped measuring sections. Each measuring section may be shaped to evenly divide the entire disc, for example, forming sectors of 72, 90, 120, or 180 degrees. Such a configuration makes it possible to efficiently perform multiple measurements on a single disc.

[0079] In another embodiment, the fluid device may have a fan-shaped disc body with a portion of a circle cut off, and be mounted at a predetermined position on a rotary table. Such a fan-shaped structure allows for an efficient design limited to the required measurement area, and can also be used as a disposable device that can be replaced after each measurement.

[0080] In yet another embodiment, the fluid device may be designed to fit within a sector-shaped region on a rotary table. In this case, the fluid device may have an irregular shape that fits into a specific sector-shaped region, rather than being the entire circle or part of a sector. This configuration increases the design flexibility of the fluid device and allows for the accommodating of diverse measurement requirements.

[0081] The fluid devices of this disclosure may be configured to move fluid using centrifugal force, and the flow path or inlet is designed to function properly under the influence of centrifugal force. The fluid devices may also have a structure that includes inlets and outlets for introducing and discharging fluid, thereby improving measurement accuracy and operability.

[0082] The fluid device of the present invention may have a structure that includes sectors formed by dividing an entire circle or a part of a circle into equal parts. In this case, the sectors may be formed with central angles of 90 degrees, 120 degrees, or 180 degrees, but are not limited thereto.

[0083] These configuration examples illustrate one embodiment of the present invention and do not limit the scope of the invention. Each component and shape can be modified as appropriate depending on the object to be measured and the design requirements.

[0084] Embodiment 10: Device Shape Figure 8 shows an example of the shape of a fluid device according to the present invention, illustrating a specific structure of a fluid device that can be attached to the aforementioned rotating disk or rotary table.

[0085] In some embodiments, a disc-shaped fluid device for rotational motion comprises a circular disc-shaped body positioned on a rotary table and configured to be rotatable; and a plurality of fan-shaped measuring sections provided on the disc-shaped body; each of the plurality of measuring sections having an internal flow path for containing fluid.

[0086] The fluid device 810 shown in Figure 8(A) is a circular, disc-shaped device with a central axis of rotation, configured to perform rotational motion. This device is provided with a plurality of measuring sections 811 to 814, each functioning as an independent area for fluid storage and measurement. Each measuring section is arranged to divide the disc equally, for example, by dividing the entire disc into four 90-degree sectors. This configuration makes it possible to perform multiple measurements simultaneously or sequentially on a single disc.

[0087] In some embodiments, the disc-shaped fluid device for rotational motion comprises a fan-shaped disc body formed by cutting off a portion of a circle and arranged on a rotary table, the disc body having an internal flow path for containing fluid.

[0088] The fluid device 820 shown in Figure 8(B) has a fan-shaped form. This device is shaped like a portion of a circular disk and is used by mounting it in a predetermined position on a rotary table. The fan-shaped design allows only the necessary measuring section to be attached, and it can be replaced for each measurement as a disposable device. This enables material savings and miniaturization of the device.

[0089] In some embodiments, the disc-shaped fluid device for rotational motion comprises (a) a disc-shaped body arranged on a rotary table and configured to be rotatable; the disc-shaped body is formed to fit within a fan-shaped region on the rotary table.

[0090] Figure 8(C) shows that the fluid device 830 has an irregular shape and is not necessarily limited to a circular or sector shape. This device is designed to fit a specific measurement section on a rotating disk and its shape and size can be flexibly changed depending on the measurement purpose and the characteristics of the fluid.

[0091] This disclosure includes the following embodiments: A001. A fluid device according to any embodiment, comprising a flow path having a fluid inlet and an outlet, wherein the flow path is configured to prevent bubble accumulation by utilizing centrifugal force. A011. A fluid device according to A001 or any embodiment, wherein the effective potential of the centrifugal force field in the flow path section between the inlet and the outlet does not have a maximum value. A012. A fluid device according to A011 or any embodiment, wherein the effective potential of the centrifugal force field in the flow path section is configured to decrease monotonically. A013. A fluid device according to A011 or any embodiment, wherein the flow path has a curved or nonlinear shape in the flow path section, and is configured to eliminate a maximum value of the effective potential within the flow path section. A014. A fluid device according to A001 or any embodiment, wherein the centrifugal force field is 5G (G = 9.80665 m / s²). ２A015. A fluid device configured to act in an acceleration range of 20G to 150G. A016. A fluid device according to A011 or any embodiment, wherein the centrifugal force field is configured to act in an acceleration range of 20G to 150G. A017. A fluid device according to A011 or any embodiment, wherein the flow path section extends in a straight line, and the angle between the central axis of the flow path section and the radius of rotation line passing through a point on the central axis is set in the range of 10 degrees to 80 degrees. A018. A fluid device according to A011 or any embodiment, wherein the flow path section has a curved shape in which the angle of inclination with respect to the radius of rotation increases as it moves away from the center of rotation, thereby configuring the tangential component of the centrifugal force acting on the fluid or bubbles in the flow path to be substantially constant over the entire length of the flow path section. A017 or any embodiment of a fluid device, wherein the curved shape is based on a logarithmic spiral. A019. A011 or any embodiment of a fluid device, wherein the cross-sectional area of ​​the flow channel is configured to increase or decrease monotonically from upstream to downstream. A021. A001 or any embodiment of a fluid device, wherein a bubble trap is located in the flow channel between the inlet and the outlet. A022. A021 or any embodiment of a fluid device, wherein the bubble trap is located in the flow channel at a position where the effective potential of the centrifugal force field has a maximum value. A023. A021 or any embodiment of a fluid device, wherein the bubble trap has a hydrophobic coated surface. A024. A021 or any embodiment of a fluid device, wherein the bubble trap is located along the radial inner wall of the flow channel. A025. A fluid device according to the embodiment of A021, A022, or any of the embodiments, wherein the bubble trap has a recess or groove and is shaped to physically capture bubbles.A026. A fluid device according to A021 or any embodiment, wherein a plurality of bubble traps are provided in the flow path section, each positioned at a different flow path location. A027. A fluid device according to A021 or any embodiment, wherein the flow path section is branched into a first branch flow path for capturing bubbles and a second branch flow path for delivering liquid, and the bubbles captured in the first branch flow path are configured to obstruct the inflow of liquid into the first branch flow path and guide the subsequent liquid to the second branch flow path. A031. A fluid device according to A001 or any embodiment, wherein the flow path section has a U-shape, and the inlet and outlet are configured to have the same effective potential. A032. A fluid device according to A031 or any embodiment, wherein the fluid in the flow path is configured to remain stationary under a centrifugal force field. A041. A001 or any embodiment of the fluid device, wherein the flow path section comprises, in order from upstream, a sample reservoir, a constricted section with a reduced flow path cross-sectional area, and a detection chamber, and a sensor is located at the bottom of the detection chamber. A051. A001 or any embodiment of the fluid device, comprising a liquid trap flow path for holding a displacement liquid, a displacement chamber filled with gas, and a displacement valve capable of opening and closing the inlet of the displacement chamber, wherein when the displacement valve is opened in a centrifugal field, the displacement liquid and the gas are replaced by the difference in specific gravity between them, and the displacement liquid fills the displacement chamber. A052. A051 or any embodiment of the fluid device, wherein the volume of the displacement chamber is set to be larger than the volume of the liquid trap flow path.

[0092] Preferred embodiments of the present invention have been shown and described herein, but it will be apparent to those skilled in the art that such embodiments are provided only as examples. The present invention is not intended to be limited by the specific examples provided herein. Although the present invention has been described with reference to the foregoing specification, the descriptions and illustrations of embodiments herein are not intended to be constrained. Those skilled in the art will be able to conceive of numerous variations, modifications, and substitutions without departing from the present invention. Furthermore, it should be understood that all aspects of the present invention are not limited to the specific descriptions, configurations, or relative proportions described herein, which depend on various conditions and variables. It should be understood that various alternative forms of the embodiments of the present invention described herein may be used when carrying out the present invention. Accordingly, the present invention is intended to cover such alternatives, modifications, variations, or equivalents. The claims of this application define the scope of the present invention, and the methods and structures within these claims, as well as their equivalents, are intended to be covered thereby.

Claims

1. A fluid device comprising a fluid channel having a fluid inlet and a fluid outlet, wherein the fluid channel is configured to prevent the accumulation of bubbles by utilizing centrifugal force.

2. A fluid device according to claim 1, wherein the effective potential of the centrifugal force field in the flow path section between the inlet and the outlet does not have a maximum value.

3. A fluid device according to claim 2, wherein the flow channel section extends in a straight line, and the angle between the central axis of the flow channel section and the radius of rotation line passing through a point on the central axis is set to a range of 10 degrees or more and 80 degrees or less.

4. A fluid device according to claim 2, wherein the flow channel section has a curved shape in which the angle of inclination with respect to the radius of rotation increases as it moves away from the center of rotation, and thereby the tangential component of the centrifugal force acting on the fluid or bubbles in the flow channel is substantially constant over the entire length of the flow channel section.

5. A fluid device according to claim 4, wherein the curved shape is based on a logarithmic spiral.

6. A fluid device according to claim 2, wherein the cross-sectional area of ​​the flow channel section is configured to increase or decrease monotonically from upstream to downstream.

7. A fluid device according to claim 1, wherein a bubble trap is disposed in the flow path section between the inlet and the outlet.

8. A fluid device according to claim 7, wherein the bubble trap is located in the flow channel section at a position where the effective potential of the centrifugal force field has a maximum value.

9. A fluid device according to claim 7, wherein the bubble trap has a recess or groove and is shaped to physically capture bubbles.

10. A fluid device according to claim 7, wherein the flow channel section is branched into a first branch channel for capturing bubbles and a second branch channel for delivering liquid, and the bubbles captured in the first branch channel are configured to obstruct the inflow of liquid into the first branch channel and guide the subsequent liquid into the second branch channel.

11. A fluid device according to claim 1, wherein the flow channel section has a U-shape, and the inlet and outlet are configured to have the same effective potential.

12. A fluid device according to claim 1, wherein the flow path section comprises, in order from upstream, a sample reservoir, a constricted section with a reduced flow path cross-sectional area, and a detection chamber, and a sensor is located at the bottom of the detection chamber.

13. A fluid device according to claim 1, comprising a liquid trap channel for holding a displacement liquid, a displacement chamber filled with gas, and a displacement valve capable of opening and closing the inlet of the displacement chamber, wherein when the displacement valve is opened in a centrifugal field, the displacement liquid and the gas are replaced by the difference in specific gravity between them, and the displacement liquid fills the displacement chamber.

14. A fluid device according to claim 13, wherein the volume of the displacement chamber is set to be larger than the volume of the liquid trap channel.

15. A fluid device according to claim 1, wherein the centrifugal force field is configured to act in an acceleration range of 20G to 150G.

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