Liquid extraction device

Abstract

This technology provides a way to retain a region for the defoaming liquid inside the liquid tank while simultaneously drawing out a portion of the defoaming liquid to the outside of the liquid tank. [Solution] A liquid extraction device 10 according to one aspect of the present disclosure comprises a region forming member 18 having a cap portion 12 which has a bottom surface 122 and a wall surface 124 rising from the outer peripheral edge of the bottom surface 122, with an opening 12H formed at the end of the wall surface 124, and forming a liquid extraction region R surrounded by the bottom surface 122 and the wall surface 124; a pipe member which is arranged in the liquid extraction region R and has a pipe tip facing the bottom surface 122; and a suction portion 14 which sucks up the liquid L present in the liquid extraction region R through the pipe member. Inside the liquid tank 11 which contains the liquid L, the cap portion 12 is positioned so that the distance from the top of the tank 114 to the opening 12H is shorter than the distance from the top of the tank 114 to the bottom surface 122.

Description

[Technical Field]

[0001] This disclosure relates to a liquid extraction device. [Background technology]

[0002] Liquids contained in liquid tanks may contain air bubbles. Techniques are known for removing air bubbles from liquids containing air bubbles (hereinafter referred to as "defoamed liquid").

[0003] Patent Document 1 discloses a technique for removing air bubbles from a liquid in a liquid container. The technique described in Patent Document 1 involves injecting liquid from the bottom of a tilted liquid container, injecting the liquid from below the inlet point, and discharging air bubbles from the top of the liquid container.

[0004] Patent Document 2 discloses a technology relating to a cover for a sensor that measures the properties of a liquid containing air bubbles. In the technology described in Patent Document 2, micropores are formed in the cover body that allow the liquid to pass through and suppress the intrusion of air bubbles. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2015-20083 [Patent Document 2] International Publication No. 2020 / 009022 [Patent Document 3] International Publication No. 2023 / 286864 [Overview of the project] [Problems that the invention aims to solve]

[0006] It is required to simultaneously measure the liquid in a liquid tank using a sensor that requires immediate response (for example, the potential sensor shown in Patent Document 3) and a sensor that requires sensing accuracy (for example, an optical sensor). When using a sensor that requires immediate response, it is necessary to secure a region of defoaming liquid inside the liquid tank. When using a sensor that requires sensing accuracy, it is difficult to ensure sensing accuracy inside the liquid tank. Therefore, when using a sensor that requires sensing accuracy, it is desirable to withdraw a portion of the liquid outside the liquid tank for measurement. However, when a portion of the liquid is withdrawn outside the liquid tank, if air bubbles are mixed into the liquid delivery pipe, it can cause blockage of the liquid delivery pipe. Therefore, it is desirable to introduce the defoaming liquid into the liquid delivery pipe rather than installing a defoaming device outside the liquid tank. Thus, in order to simultaneously measure using a sensor that requires immediate response and a sensor that requires sensing accuracy, it is necessary to secure a region of defoaming liquid inside the liquid tank while withdrawing a portion of the defoaming liquid outside the liquid tank. Conventionally, there has been no device that can secure a region of defoaming liquid inside the liquid tank while withdrawing a portion of the defoaming liquid outside the liquid tank.

[0007] The technology described in Patent Document 1 removes air bubbles outside the liquid tank containing the liquid. Therefore, the technology described in Patent Document 1 cannot secure a region for the defoaming liquid inside the liquid tank. Furthermore, the technology described in Patent Document 1 introduces the liquid containing air bubbles into the liquid delivery pipe. The technology described in Patent Document 2 can secure a region for the defoaming liquid inside the liquid tank, but it cannot simultaneously draw out a portion of the defoaming liquid to the outside of the liquid tank.

[0008] Furthermore, in the technologies described in Patent Documents 1 and 2, it is difficult to ensure sufficient defoaming performance when a large amount of air bubbles are mixed in with the liquid volume. For example, in the technology described in Patent Document 1, the defoaming device outside the liquid supply pipe and liquid tank is filled with air bubbles. In the technology described in Patent Document 1, in order to ensure a sufficient amount of defoamed liquid, it is necessary to suppress the inflow of air bubbles into the defoaming device by adding a complex configuration such as a pump that returns liquid with a high air bubble ratio to the inside of the liquid tank. In the technology described in Patent Document 2, the inside of the cover is filled with air bubbles, making it impossible to ensure a sufficient amount of defoamed liquid. [Means for solving the problem]

[0009] A liquid extraction device according to one aspect of the present disclosure comprises a region forming member having a cap portion that has a bottom surface and a wall surface rising from the outer peripheral edge of the bottom surface, with an opening formed at the end of the wall surface, forming a liquid extraction region surrounded by the bottom surface and the wall surface; a pipe member disposed in the liquid extraction region and having a pipe tip facing the bottom surface; and a suction portion that sucks up the liquid present in the liquid extraction region via the pipe member. Inside a liquid tank containing liquid, the cap portion is positioned such that the distance from the top of the tank to the opening is shorter than the distance from the top of the tank to the bottom surface.

[0010] In a liquid extraction device according to one aspect of this disclosure, a liquid extraction region is formed by a cap portion having a bottom surface and walls. The opening of the cap portion is positioned closer to the top of the liquid tank than the bottom surface. That is, the cap portion is positioned in the liquid tank such that its opening is above the bottom surface. The opening of the cap portion promotes the inflow of liquid while suppressing the inflow of air bubbles mixed in the liquid. The liquid extraction region formed inside the cap portion can be said to be the region of the defoamed liquid. Furthermore, the tip of the pipe member is positioned in the liquid extraction region and faces the bottom surface of the cap portion. By suctioning through the pipe member, the liquid present in the liquid extraction region is drawn into the pipe member. This makes it possible to extract a portion of the defoamed liquid to the outside of the liquid tank while maintaining the region of the defoamed liquid inside the liquid tank. [Effects of the Invention]

[0011] According to the present disclosure, it is possible to provide a technique capable of securing a region of a defoaming liquid inside a liquid tank and extracting a part of the defoaming liquid outside the liquid tank.

Brief Description of the Drawings

[0012] [Figure 1] FIG. 1 is a schematic diagram showing an example of the overall configuration of a measurement system. [Figure 2] FIG. 2 is a schematic diagram partially showing an example of a liquid extraction device. [Figure 3] FIG. 3 is a schematic diagram showing an example of the control of the suction speed. [Figure 4] FIG. 4 is a schematic diagram showing an example of the flow inside a liquid tank. [Figure 5] FIG. 5 is a diagram showing a first simulation example of the liquid flow. [Figure 6] FIG. 6 is a diagram showing a second simulation example of the liquid flow. [Figure 7] FIG. 7 is a diagram showing a third simulation example of the liquid flow. [Figure 8] (a) of FIG. 8 is a diagram showing a first arrangement example of the cap portion 12. (b) of FIG. 8 is a diagram showing a second arrangement example of the cap portion 12. (c) of FIG. 8 is a diagram showing a third arrangement example of the cap portion 12. [Figure 9] FIG. 9 is a diagram showing an arrangement example of the region forming member. [Figure 10] (a) of FIG. 10 is a graph showing an example of the measurement result of the absorbance according to an embodiment. (b) of FIG. 10 is a graph showing an example of the measurement result of the absorbance according to a comparative example.

Modes for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the description of the drawings, the same reference numerals are assigned to the same elements, and duplicate descriptions are omitted.

[0014] Figure 1 is a schematic diagram showing an example of the overall configuration of the measurement system 1. The measurement system 1 comprises a liquid extraction device 10, a first measuring device 20, and a second measuring device 30.

[0015] The liquid extraction device 10 comprises a liquid tank 11, a pipe member 13 (liquid delivery pipe), a suction unit 14 (suction machine), a control device 15, and a region forming member 18. The region forming member 18 comprises a cap unit 12, a fixing unit 16 (fixing device), and a connecting unit 17.

[0016] The liquid tank 11 is a container for holding liquid L. The liquid tank 11 may be, for example, a culture tank for holding a culture medium used for culturing microorganisms. Liquid L may be a culture medium. Bubbles B are mixed into the liquid L by introducing any gas (e.g., air). There may or may not be a flow within the liquid tank 11.

[0017] The cap portion 12 is a bottomed cylindrical container (for example, a bottomed cylindrical shape) placed inside the liquid tank 11. The entire cap portion 12 is placed in the liquid L with its opening facing upwards towards the liquid tank 11. That is, the cap portion 12 is submerged in the liquid L. The liquid L flows into the interior of the cap portion 12. The cap portion 12 forms a liquid withdrawal region R near the bottom.

[0018] The tubing member 13 is a tube that moves liquid L. The tubing member 13 is inserted inside the cap portion 12. The tip of the tubing member 13 (tube tip) is positioned in the liquid withdrawal region R. The tubing member 13 takes in liquid L from the liquid withdrawal region R and moves liquid L to the outside of the liquid tank 11. For example, the tubing member 13 sends liquid L from the liquid tank 11 to the second measuring device 30. The tubing member 13 may also send liquid L from the second measuring device 30 to the liquid tank 11. In other words, the tubing member 13 may circulate liquid L. Liquid L moves inside the tubing member 13 along direction F.

[0019] The suction unit 14 is a device that sucks up the liquid L present in the liquid extraction region R via the tubular member 13. The suction unit 14 is, for example, a pump. The suction unit 14 may operate according to the control of the control device 15.

[0020] The control device 15 is a device that controls the suction speed of the suction unit 14. The control device 15 transmits, for example, a control signal to the suction unit 14 to adjust the suction speed. The control device 15 may be integrated into the suction unit 14.

[0021] The fixing part 16 is fixed to the liquid tank 11. The connecting part 17 connects the fixing part 16 and the cap part 12. The fixing part 16, the cap part 12, and the connecting part 17 may be integrally formed. The region forming member 18 fixes the fixing part 16 to the liquid tank 11 and places the cap part 12 inside the liquid tank 11 via the connecting part 17.

[0022] The first measuring device 20 is a device that performs measurements (first measurements) requiring immediate response inside the liquid tank 11. The first measuring device 20 comprises a potential sensor 21 and a potential measuring device 22.

[0023] The potential sensor 21 is a rod-shaped sensor that detects the potential difference between specific points. The potential sensor 21 is inserted inside the cap portion 12. The tip of the potential sensor 21 (sensor tip) is positioned in the liquid extraction region R. The potential sensor 21 performs measurements in the liquid extraction region R. The potential sensor 21 outputs the detected signal to the potential measuring device 22. The potential measuring device 22 is a device that processes the signal acquired from the potential sensor 21 and stores it as data.

[0024] The second measuring device 30 is a device that performs measurements (second measurements) requiring sensing accuracy outside the liquid tank 11. The second measuring device 30 comprises a flow cell 31, a light source 32, and a detection device 33.

[0025] The flow cell 31 is a measuring container made of glass or the like, which has high light transmittance. A tubular member 13 is connected to one end of the flow cell 31 and the other end. Liquid L flows into the flow cell 31 through one tubular member 13. The flow cell 31 discharges the liquid L through the other tubular member 13. The light source 32 irradiates the flow cell 31 with light. The detection device 33 measures the absorbance using the transmitted light from the flow cell 31.

[0026] Figure 2 is a schematic diagram partially showing an example of a liquid extraction device 10. Figure 2 shows a liquid tank 11, a cap section 12, a tubular member 13, and a suction section 14. The liquid tank 11 contains liquid L mixed with air bubbles B.

[0027] The liquid tank 11 comprises a tank bottom surface 111, a tank inner surface 112, a tank side surface 113 (tank outer surface), and a tank top surface 114. The tank bottom surface 111 is the surface corresponding to the bottom surface of the container. The tank inner surface 112 is the surface corresponding to the inner surface of the container. The tank side surface 113 is the surface opposite to the tank inner surface 112. The tank top surface 114 is the region facing the tank bottom surface 111. An opening may be formed in the tank top surface 114, or a lid may be attached. A pipe member 13 or the like may be inserted from the tank top surface 114.

[0028] The cap portion 12 comprises a lower surface 121, a bottom surface 122, a wall surface 124, and an upper end portion 125. The lower surface 121 is a surface that intersects the central axis of the cap portion 12. The bottom surface 122 is the surface opposite to the lower surface 121. The bottom surface 122 faces the pipe tip 131 of the pipe member 13, which will be described later. The wall surface 124 rises from the outer peripheral edge 123 of the bottom surface 122. The wall surface 124 extends in a direction away from the bottom surface 122. The wall surface 124 surrounds the central axis of the cap portion 12. The upper end portion 125 is the end of the wall surface 124 in the direction away from the bottom surface 122. An opening 12H is formed in the upper end portion 125.

[0029] One end of the cap portion 12 is closed by the bottom surface 121. The other end of the cap portion 12 is open by the opening 12H. The cap portion 12 forms a liquid extraction region R surrounded by the bottom surface 122 and the wall surface 124. The liquid extraction region R may be, for example, a region closer to the bottom surface 122 than to the center of the cap portion 12 in the axial direction.

[0030] The cap portion 12 is positioned inside the liquid tank 11. Its lower surface 121 faces the bottom surface 111 of the liquid tank 11. Its wall surface 124 faces the inner surface 112 of the liquid tank 11. The opening 12H is directed toward the upper part 114 of the liquid tank 11. The opening 12H is directed toward the surface of the liquid L. Liquid L constantly flows in through the opening 12H. The cap portion 12 is positioned such that the distance from the upper part 114 of the liquid tank 11 to the opening 12H is shorter than the distance from the upper part 114 to the bottom surface 122. The cap portion 12 may be positioned in the center of the liquid tank 11, or it may be positioned closer to the inner surface 112 of the liquid tank 11.

[0031] The tubular member 13 may be inserted into the liquid tank 11, for example, from the upper part 114 of the liquid tank 11. Alternatively, the tubular member 13 may be inserted into the cap portion 12 through the opening 12H of the cap portion 12. The tip 131 of the tubular member 13 is positioned in the liquid withdrawal area R and faces the bottom surface 122.

[0032] In the axial direction of the cap portion 12, the tip of the tube 131 is positioned near the bottom surface 122. The area near the bottom surface 122 may be, for example, a region closer to the bottom surface 122 than the center in the axial direction of the cap portion 12. That is, the area near the bottom surface 122 may be the area from a position half the height of the cap portion 12 to the bottom surface 122. Furthermore, the tip of the tube 131 is positioned so as not to obstruct the inflow of liquid L into the liquid withdrawal region R. Specifically, the tip of the tube 131 may be positioned near the bottom surface 122 while maintaining a distance from the bottom surface 122 that is greater than or equal to the radius of the tube member 13. In the radial direction of the cap portion 12, the tip of the tube 131 may or may not coincide with the axis of the central axis of the cap portion 12.

[0033] Figure 3 is a schematic diagram showing an example of suction speed control. Figure 3 shows a liquid tank 11, a cap section 12, a tubing member 13, a suction section 14, and a control device 15. The liquid tank 11 contains a liquid L mixed with bubbles B and suspended matter G. Bubbles B rise (float) along the direction D1 toward the upper part 114 of the liquid tank 11. Suspended matter G sinks along the direction D2 toward the lower part of the liquid tank 11. Suspended matter G is, for example, microorganisms or debris.

[0034] The suction unit 14 draws out the liquid L, causing the liquid L present in the liquid drawout region R to flow into the pipe member 13. Additionally, the suction unit 14 draws out the liquid L, causing the liquid L present outside the cap portion 12 to flow into the cap portion 12 through the opening 12H. Assuming there is no inflow of liquid L from the opening 12H, the liquid level of the liquid L near the opening 12H will descend along the direction D3 toward the bottom surface 122 of the cap portion 12.

[0035] The control device 15 may control the suction speed so that the rising speed of the bubbles B in the liquid L is greater than or equal to the falling speed of the liquid level caused by the suction of the suction unit 14. For example, the control device 15 may control the suction speed so as to satisfy the following condition (1).

[0036]

number

[0037] The left-hand side of condition (1) is the rising velocity (floating velocity) of bubble B, derived from Stokes' equation. Here, r B [mm] is the radius of bubble B, which we want to prevent from being introduced. ρ L [g / L] is the density of the liquid L drawn. B [g / L] is the density of bubble B. g[m / s 2 ] is the acceleration due to gravity. μ[mPa·s] is the viscosity of liquid L.

[0038] The right side in conditional expression (1) is the descending speed of the liquid L near the opening 12H of the cap portion 12 caused by the extraction of the liquid L by the suction portion 14. Here, V p [mL / s] is the suction speed by the suction portion 14. S [mm 2 is the cross-sectional area obtained by subtracting the exclusive area fraction by the pipe member 13 and the potential sensor 21 from the cross-sectional area horizontally cut near the opening 12H of the cap portion 12.

[0039] In the cultivation of microorganisms, the density ρ of the bubbles B B [g / L] is significantly smaller compared to the density ρ of the liquid L to be extracted L [g / L]. Therefore, the density ρ of the bubbles B B [g / L] may be treated as zero.

[0040] The suction speed V p [mL / s] can practically remove almost all the bubbles B over a wide range. When strict removal of the bubbles B is necessary, the suction speed V p [mL / s] may be directly determined by judgment based on the measurement system of the liquid L. For example, when measurements are made a sufficient number of times within a certain time by the measurement system of the liquid L, the suction speed V p [mL / s] under the condition that 50% or more of the measurement times indicate the true value may be directly determined. The true value is the same as the value measured under the condition of completely removing the bubbles B.

[0041] The radius r of the bubbles B B [mm] may be determined by prior confirmation. For example, when it is possible to extract the liquid L without the bubble B removal function in advance, or when the size of the bubble B can be confirmed, the size of the main bubble B may be visually confirmed or confirmed under a microscope. Also, based on the radius r of the bubble B B [mm] determined by prior confirmation, the range of the suction speed V p [mL / s] may be determined.

[0042] The control device 15 may control the suction speed so that the settling speed of the suspended matter G in the liquid L is less than or equal to the rate at which the liquid level drops due to the suction of the suction unit 14. For example, the control device 15 may control the suction speed so as to satisfy the following condition (2).

[0043]

number

[0044] The left-hand side of condition (2) is the settling velocity of the suspended matter G (particles) derived from Stokes' equation. Here, r G [mm] is the radius of the suspension G. L [g / L] is the density of the liquid L drawn. G [g / L] is the density of the suspended substance G. g[m / s] 2 ] is the acceleration due to gravity. μ[mPa·s] is the viscosity of liquid L.

[0045] The right-hand side of conditional equation (2) is the downward velocity of the liquid L near the opening 12H of the cap portion 12, which is caused by the withdrawal of the liquid L by the suction portion 14. Here, V p [mL / s] is the suction speed by the suction unit 14. S[mm 2 This is the cross-sectional area obtained by subtracting the area occupied by the pipe member 13 and the potential sensor 21 from the cross-sectional area obtained by horizontally cutting off the area near the opening 12H of the cap portion 12.

[0046] The control device 15 may control the suction speed according to the conditions for culturing microorganisms. For example, in condition equation (1), the radius r of the bubble B that you want to prevent from entering is B The density may be 0.05 [mm] or greater. Density ρ of the liquid L to be drawn. L The concentration may be in the range of 1000 to 1400 [g / L]. The liquid viscosity μ of liquid L may be in the range of 0.8 to 100 [mPa·s]. This range is based on water at 30°C and 90% concentration glycerin at 30°C, etc. The conditions for culturing microorganisms may be appropriately applied to condition formula (2).

[0047] Figure 4 is a schematic diagram showing an example of the flow within the liquid tank 11. The liquid extraction device 10 may further include a stirring unit 19 (agitator) for stirring the liquid L contained in the liquid tank 11. Figure 4 shows the liquid tank 11, cap unit 12, pipe member 13, suction unit 14, control device 15, and stirring unit 19.

[0048] The stirring unit 19 is attached, for example, to the top of the liquid tank 11 (e.g., the top of the tank 114). The stirring unit 19 rotates its shaft in direction D4 around the axis of the shaft using power from a motor or the like. The stirring unit 19 stirs the liquid L with an impeller attached to the shaft. The stirring creates a flow within the liquid tank 11. Figure 4 shows the flow from left to right in the liquid tank 11 due to stirring.

[0049] The cap portion 12 is directly affected by the flow within the liquid tank 11. For example, a cavity flow C is generated by the contact between the liquid L filling the cap portion 12 and the flow near the opening 12H. The cavity flow C creates a downward flow inside the cap portion 12. The cavity flow C varies greatly depending on the size of the opening 12H and the kinematic viscosity coefficient of the liquid L.

[0050] Figures 5 to 7 show the first to third simulation examples of the liquid L flow. Figures 5 to 7 show the aspect ratio of the cap portion 12 and the kinematic viscosity coefficient of liquid L [cm 2 The results of the simulation of the liquid L flow for each combination of [ / s] are shown. The aspect ratio of the cap portion 12 is the ratio of the height (depth) of the cap portion 12 to the diameter of the opening 12H. The height (depth) of the cap portion 12 refers to the height of the wall surface 124, or the distance from the bottom surface 122 to the upper end portion 125. Figures 5 to 7 show a comparison of the vertical velocity of the liquid L inside the cap portion 12 and the flow velocity (1 m / s) of the liquid tank 11 using color bars. The arrows in Figures 5 to 7 indicate the flow vectors.

[0051] Figure 5 shows a pattern with an aspect ratio of 2:1. Figure 6 shows a pattern with an aspect ratio of 1:1. Figure 7 shows a pattern with an aspect ratio of 0.5:1. In other words, the aspect ratio of the cap portion 12 can be 2:1, 1:1, or 0.5:1. The kinematic viscosity can be 0.01 (similar to water), 0.1, 1, or 10 (similar to glycerin) in four patterns. The combinations of aspect ratio and kinematic viscosity result in 3 x 4 = 12 patterns.

[0052] If the aspect ratio of the cap portion 12 is 2:1 or 1:1, then the diameter of the opening 12H is less than or equal to the height (depth). In this case, the flow velocity near the bottom surface 122 of the cap portion 12 is 1 / 100 or less (approximately 1 / 1000 to 1 / 100) of the flow velocity in the liquid tank 11. Here, the tip 131 of the pipe member 13 may be positioned in a region where the flow velocity is 1 / 100 or less (approximately 1 / 1000 to 1 / 100) of the flow velocity in the liquid tank 11.

[0053] Figure 8(a) shows a first arrangement example of the cap portion 12. The first arrangement example omits the fixing portion 16 and the connecting portion 17. In the first arrangement example, the cap portion 12 is directly fixed to the liquid tank 11. For example, the lower surface 121 of the cap portion 12 may be fixed to the bottom surface 111 of the liquid tank 11.

[0054] Figure 8(b) shows a second arrangement example of the cap portion 12. In the second arrangement example, the region forming member 18A includes a fixing portion 16 and a connecting portion 17A. The region forming member 18A is an example of the region forming member 18.

[0055] The fixing portion 16 is formed, for example, in a cylindrical shape and fixed to the liquid tank 11. The fixing portion 16 may hold the potential sensor 21 and the tubular member 13. The connecting portion 17A is an example of the connecting portion 17. The connecting portion 17A is formed in the shape of a rod, plate, or column. The connecting portion 17A connects the upper end portion 125, which has an opening 12H, to the fixing portion 16. For example, the connecting portion 17A connects the edge of the upper end portion 125 to the edge of the fixing portion 16. The connecting portion 17A may connect the upper end portion 125 and the fixing portion 16 at multiple locations. At least a part of the connecting portion 17A may be placed in the liquid L. The region forming member 18A allows the cap portion 12 to be placed in the liquid tank 11 with a simple configuration.

[0056] Figure 8(c) shows a third arrangement example of the cap portion 12. In the third arrangement example, the region forming member 18B includes a fixing portion 16 and a connecting portion 17B. The region forming member 18B is an example of the region forming member 18.

[0057] The fixing portion 16 is the same as in Figure 8(b). The connecting portion 17B is an example of the connecting portion 17. The connecting portion 17B is formed in a cylindrical shape. For example, the connecting portion 17B is hollow and integrated with the wall surface 124 of the cap portion 12. It connects the upper end portion 125, where the opening 12H is formed, to the fixing portion 16. For example, the connecting portion 17B connects the edge of the upper end portion 125 to the edge of the fixing portion 16. At least a part of the connecting portion 17B may be placed in the liquid L.

[0058] The connecting portion 17B has at least one or more holes 17H formed therein. Liquid L and bubbles B flow into the region forming member 18B through at least one or more holes 17H. The region forming member 18B allows liquid L and bubbles B to flow out through at least one or more holes 17H. The area of ​​at least one or more holes 17H may be made large enough to allow sufficient inflow and outflow of liquid L and bubbles B. At least one or more holes 17H are formed above the upper end portion 125.

[0059] In the first to third configuration examples shown in Figures 8(a) to 8(c), the height H of the cap portion 12 is the same. When there is flow in the liquid tank 11, in the example shown in Figure 8(a) or 8(b), liquid L easily flows into the inside of the cap portion 12 through the opening 12H. In contrast, in the region-forming member 18B shown in Figure 8(c), the flow in the liquid tank 11 collides with the side surface of the connecting portion 17B. Therefore, with the region-forming member 18B, it is difficult for liquid L to flow into the inside of the cap portion 12. Because flow contact is suppressed, the region-forming member 18B can suppress cavity flow.

[0060] Figure 9 shows an example of the arrangement of the region-forming member 18B. The region-forming member 18B is inserted at an angle to the bottom surface 111 of the liquid tank 11, with its central axis X. At least one or more holes 17H face the upper part 114 of the liquid tank 11. For example, the region-forming member 18B is inserted at an angle into the liquid tank 11 from the side surface 113 of the liquid tank 11.

[0061] The connecting portion 17B may have a pair of holes 17H formed on either side of the central axis X. For example, in the connecting portion 17B, the pair of holes 17H may be provided at symmetrical positions with respect to the central axis X.

[0062] Figure 10(a) is a graph showing an example of absorbance measurement results related to the embodiment. In the embodiment, the liquid extraction device 10 is applied to a culture tank used for culturing microorganisms. Figure 10(a) shows the results of measuring the absorbance of the culture medium extracted from the culture tank. In Figure 10(a), the horizontal axis represents time and the vertical axis represents absorbance. In Figure 10(a), there is little variation in the data. That is, it is shown that the measurement is stable.

[0063] Figure 10(b) is a graph showing an example of absorbance measurement results for the comparative example. In the comparative example, the liquid extraction device 10 is not applied to the culture tank used for culturing microorganisms. Figure 10(b) shows the results of measuring the absorbance of the culture medium extracted from the culture tank. In Figure 10(b), the horizontal axis represents time and the vertical axis represents absorbance. In Figure 10(b), the data is scattered up and down. That is, it indicates that the measurement is unstable. The data scattering is due to light scattering by air bubbles in the liquid L flowing into the flow cell 31, or changes in light transmittance, etc.

[0064] As described above, the liquid extraction device 10 forms a region of defoamed liquid inside the liquid tank 11. The liquid extraction device 10 also extracts the defoamed liquid from the region of defoamed liquid to the outside of the liquid tank 11.

[0065] A liquid extraction device 10 according to one aspect of the present disclosure comprises a region forming member 18 having a cap portion 12 having a bottom surface 122 and a wall surface 124 rising from the outer peripheral edge of the bottom surface 122, with an opening 12H formed at the end of the wall surface 124, forming a liquid extraction region R surrounded by the bottom surface 122 and the wall surface 124; a pipe member disposed in the liquid extraction region R and having a pipe tip facing the bottom surface 122; and a suction portion 14 that sucks up the liquid L present in the liquid extraction region R through the pipe member. Inside the liquid tank 11 containing the liquid L, the cap portion 12 is positioned so that the distance from the top of the tank 114 to the opening 12H is shorter than the distance from the top of the tank 114 to the bottom surface 122.

[0066] In the liquid extraction device 10 according to one aspect of this disclosure, a liquid extraction region R is formed by a cap portion 12 having a bottom surface 122 and a wall surface 124. The opening 12H of the cap portion 12 is positioned closer to the upper part 114 of the liquid tank 11 than the bottom surface 122. That is, the cap portion 12 is positioned in the liquid tank 11 such that the opening 12H is higher than the bottom surface 122. The opening 12H of the cap portion 12 promotes the inflow of liquid L while suppressing the inflow of air bubbles B mixed in the liquid L. The liquid extraction region R formed inside the cap portion 12 can be said to be the region of the defoaming liquid. In addition, the tip 131 of the pipe member 13 is positioned in the liquid extraction region R and faces the bottom surface 122 of the cap portion 12. The suction portion 14 sucks through the pipe member 13, and the liquid L present in the liquid extraction region R is taken into the pipe member 13. This allows a portion of the defoaming liquid to be drawn out of the liquid tank 11 while maintaining a region for the defoaming liquid inside the liquid tank 11.

[0067] Furthermore, the cap portion 12 functions as a cover surrounding the tip 131 of the pipe member 13. Even if a large amount of air bubbles B are mixed in the liquid L, the inside of the cap portion 12 will not be filled with air bubbles B. Therefore, the liquid extraction device 10 can extract the defoamed liquid stably. In addition, the cap portion 12 can be made to take up little space, making it easy to handle. Since the defoamed liquid is taken into the pipe member 13, clogging of the pipe member 13 can also be prevented.

[0068] The liquid extraction device 10 includes a control device 15 that controls the suction speed of the suction section 14. The control device 15 controls the suction speed so that the rate at which bubbles rise in the liquid L is greater than or equal to the rate at which the liquid level falls due to the suction of the suction section 14. When suction is performed by the suction section 14, the liquid level (liquid level) inside the cap section 12 falls, and liquid L constantly flows in from the opening 12H. By controlling the suction speed so that the rate at which the liquid level falls (assuming no inflow of liquid L from the opening 12H) is less than or equal to the rate at which bubbles B rise, the mixing of bubbles B into the pipe member 13 can be further reduced.

[0069] The control device 15 controls the suction speed so that the settling speed of the suspended matter G in the liquid L is less than or equal to the rate at which the liquid level drops due to suction from the suction unit 14. By controlling the suction speed so that the rate at which the liquid level drops, assuming no inflow of liquid L from the opening 12H, is less than or equal to the settling speed of the suspended matter G, it is possible to suppress the settling of the suspended matter G at the bottom surface 122 of the cap unit 12. As a result, the uneven distribution of suspended matter G in the liquid L taken into the pipe member 13 can be reduced.

[0070] The liquid extraction device 10 includes a stirring unit 19 for stirring the liquid L contained in the liquid tank 11. The diameter of the opening 12H is less than or equal to the height from the bottom surface 122 to the opening 12H. The stirring by the stirring unit 19 creates a flow in the liquid L in the liquid tank 11. The cap portion 12 is directly affected by the flow in the liquid tank 11. For example, a cavity flow C is generated by the contact between the liquid L filling the cap portion 12 and the flow near the opening 12H. The cavity flow C creates a downward flow from the opening 12H to the bottom surface 122. The cavity flow C varies greatly depending on the size of the opening 12H and the kinematic viscosity coefficient of the liquid L. Here, if the diameter of the opening 12H is less than or equal to the height, the downward flow due to the cavity flow C can be suppressed. For example, the flow velocity near the bottom surface 122 of the cap portion 12 becomes 1 / 100 or less of the flow velocity in the liquid tank 11. This suppresses the movement of air bubbles B from the opening 12H to the vicinity of the bottom surface 122 in conjunction with the cavity flow C. As a result, the incorporation of air bubbles B into the pipe member 13 can be further reduced.

[0071] The region-forming member 18 comprises a fixing portion 16 fixed to the liquid tank 11 and a connecting portion 17 connecting the fixing portion 16 and the cap portion 12. The fixing portion 16, the cap portion 12, and the connecting portion 17 are integrated. The fixing portion and the cap portion 12 are connected by the connecting portion 17, and because they are integrated, they can be treated as a single region-forming member 18. By inserting the region-forming member 18 from the outside in accordance with the structure of the liquid tank 11, it becomes easy to place it inside the liquid tank 11. In addition, the stability of the cap portion 12 is improved.

[0072] The connecting portion 17B has a hollow shape that is integrated with the wall surface 124 of the cap portion 12. At least one hole 17H ​​is formed in the connecting portion 17B. Because the connecting portion 17B has a hollow shape that is integrated with the wall surface 124, the connection strength between the connecting portion 17B and the cap portion 12 is improved. In addition, the connecting portion 17B functions as a cover that surrounds the central axis X of the region forming member 18B. Even when there is flow in the liquid tank 11, the inflow of liquid L into the cap portion 12 can be suppressed. Furthermore, because at least one hole 17H ​​is formed in the connecting portion 17B, the inflow of liquid L and the discharge of air bubbles B can be promoted.

[0073] The region-forming member 18B is inserted at an angle to the bottom surface 111 of the liquid tank 11, with its central axis X. At least one hole 17H ​​faces the upper part 114 of the liquid tank 11. If the liquid tank 11 is large, it may be difficult to position the cap portion 12 from the upper part 114 of the liquid tank 11. By inserting the region-forming member 18 at an angle from the side surface 113 of the liquid tank 11, the cap portion 12 can be easily positioned. In addition, since at least one hole 17H ​​faces the upper part 114 of the liquid tank 11, the inflow of liquid L and the discharge of air bubbles B can be promoted.

[0074] [Differentiation] This disclosure is not necessarily limited to the embodiments described above, and various modifications are possible without departing from its essence.

[0075] In this embodiment, an example has been described in which measurements are taken inside the liquid tank 11 using a potential sensor and outside the liquid tank 11 using a light sensor, taking into consideration responsiveness and accuracy, but the invention is not limited to this. Various types and arrangements of sensors may be selected according to the measurement needs. For example, an image monitor camera, a dissolved oxygen (DO) sensor, or an RGB sensor for measuring the color of the liquid may be placed inside the liquid tank 11. A microscope camera may be placed outside the liquid tank 11. Furthermore, the various sensors may be placed only inside the liquid tank 11, or only outside the liquid tank 11.

[0076] In this embodiment, the tubing member 13 is described as circulating the liquid L that has been moved outside the liquid tank 11 by returning it to the inside of the liquid tank 11, but this is not limited to this. For example, the tubing member 13 may move the liquid L that has been measured by the second measuring device 30 to another liquid tank. The liquid L that has been measured by the second measuring device 30 may be discarded.

[0077] [Note] The gist of this disclosure is as follows: [1] A region forming member having a cap portion having a bottom surface and a wall surface rising from the outer peripheral edge of the bottom surface, with an opening formed at the end of the wall surface, the cap portion forming a liquid extraction region surrounded by the bottom surface and the wall surface, A pipe member is provided, which is located in the liquid extraction region and has a pipe tip facing the bottom surface, The system includes a suction unit that sucks up the liquid present in the liquid extraction region via the aforementioned tubular member, Inside the liquid tank containing the liquid, the cap portion is positioned such that the distance from the top of the liquid tank to the opening is shorter than the distance from the top of the tank to the bottom surface. Liquid extraction device. [2] The system includes a control device for controlling the suction speed of the suction unit, The control device controls the suction speed such that the rate at which bubbles rise in the liquid is greater than or equal to the rate at which the liquid level falls due to suction from the suction unit. [1] The liquid extraction device described above. [3] The liquid extraction device according to [2], wherein the control device controls the suction speed such that the settling speed of the suspended matter in the liquid is less than or equal to the rate at which the liquid level drops due to the suction of the suction unit. [4] The liquid tank is equipped with a stirring unit for stirring the liquid contained within it. The diameter of the opening is less than or equal to the height from the bottom surface to the opening. A liquid extraction device as described in any of [1] to [3]. [5] The region-forming member comprises a fixing portion fixed to the liquid tank and a connecting portion connecting the fixing portion and the cap portion. The fixing part, the cap part, and the connecting part are integrated into one unit. A liquid extraction device as described in any of [1] to [4]. [6] The connecting portion has a hollow shape that is integrated with the wall surface of the cap portion. At least one hole is formed in the connecting portion. [5] The liquid extraction device described above. [7] The region-forming member has the central axis of the connecting portion inserted diagonally to the bottom surface of the liquid tank, The at least one of the holes is directed towards the top of the liquid tank. [6] The liquid extraction device described above. [Explanation of Symbols]

[0078] 1...Measurement system, 10...Liquid extraction device, 11...Liquid tank, 12...Cap section, 13...Tube member, 14...Suction section, 15...Control device, 16...Fixing section, 17, 17A, 17B...Connecting section, 18, 18A, 18B...Region forming member, 19...Agitation section, 20...First measuring device, 21...Potential sensor, 22...Potential measuring device, 30...Second measuring device, 31...Flow cell, 32...Light Source, 33...Detection device, 111...Bottom of tank, 112...Inner surface of tank, 113...Side of tank, 114...Top of tank, 121...Bottom surface, 122...Bottom, 123...Outer edge, 124...Wall surface, 125...Upper end, 131...Tube tip, 12H...Opening, 17H...Hole, B...Air bubble, C...Cavity flow, F...Direction, G...Suspension, H...Height, L...Liquid, D1, D2, D3, D4...Direction, X...Central axis.

Claims

1. A region forming member having a cap portion having a bottom surface and a wall surface rising from the outer peripheral edge of the bottom surface, with an opening formed at the end of the wall surface, the cap portion forming a liquid extraction region surrounded by the bottom surface and the wall surface, A pipe member is provided, which is located in the liquid extraction region and has a pipe tip facing the bottom surface, The system includes a suction unit that sucks up the liquid present in the liquid extraction region via the aforementioned tubular member, Inside the liquid tank containing the liquid, the cap portion is positioned such that the distance from the top of the liquid tank to the opening is shorter than the distance from the top of the tank to the bottom surface. Liquid extraction device.

2. The system includes a control device for controlling the suction speed of the suction unit, The control device controls the suction speed such that the rate at which bubbles rise in the liquid is greater than or equal to the rate at which the liquid level falls due to suction from the suction unit. The liquid extraction device according to claim 1.

3. The liquid extraction device according to claim 2, wherein the control device controls the suction speed such that the settling speed of the suspended matter in the liquid is less than or equal to the rate at which the liquid level drops due to the suction of the suction unit.

4. The liquid tank is equipped with a stirring unit for stirring the liquid contained within it. The diameter of the opening is less than or equal to the height from the bottom surface to the opening. The liquid extraction device according to claim 1.

5. The region-forming member comprises a fixing portion fixed to the liquid tank and a connecting portion connecting the fixing portion and the cap portion. The fixing part, the cap part, and the connecting part are integrated into one unit. The liquid extraction device according to claim 1.

6. The connecting portion has a hollow shape that is integrated with the wall surface of the cap portion. At least one hole is formed in the connecting portion. The liquid extraction device according to claim 5.

7. The region-forming member has the central axis of the connecting portion inserted diagonally to the bottom surface of the liquid tank, The at least one of the holes is directed towards the top of the liquid tank. The liquid extraction device according to claim 6.

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