Surface tension measuring apparatus, purification apparatus, surface tension measuring method, and purification method

Abstract

The present invention provides a surface tension measuring device that enables highly accurate measurements when a series of processes, including supplying the measuring liquid into the device, measuring surface tension, and cleaning the measuring probe and confirming its cleanliness, are performed automatically and continuously. [Solution] The surface tension measuring device is equipped with a surface tension measuring means that measures the surface tension of a first liquid supplied into a first container using a plate method with a measuring probe connected to a load cell. The surface tension measuring means is also used to measure the surface tension of a second liquid contained in a second container when checking the cleanliness of the cleaned measuring probe. Furthermore, at least one of (i) the measuring probe and (ii) the first container and the second container is configured to be movable within the surface tension measuring device, and if the measuring probe is configured to be movable, the measuring probe is equipped with a vibration suppression mechanism.

Description

Technical Field

[0001] The present invention relates to a surface tension measuring device, a purification device, a surface tension measuring method, and a purification method.

Background Art

[0002] In recent years, for the purpose of improving productivity, production methods called "self-completion of each process" have been introduced in various fields, in which the quality in each process of the production line is completely managed for each process to prevent non-conforming products from flowing to the next process. As a means to efficiently execute such production methods and further improve productivity, automation of quality control in each process is one of the effective means.

[0003] For example, in the production of chemical products, in order to achieve productivity improvement, an in-line automatic analyzer is introduced in each process of the production line, and physical property values that affect quality are automatically measured in real time, and when the physical property value exceeds a predetermined value, it is automatically sent to the next process. As a result, self-completion of each process, optimization of process time, and labor saving are realized, and productivity improvement is realized.

[0004] On the other hand, as a coloring material used in an inkjet recording device, dyes are widely used. Dyes are excellent in color development and are also widely used in the dyeing of fibers and woven fabrics other than in the field of inkjet recording devices.

[0005] In an inkjet recording device that discharges ink containing a dye as a coloring material from a recording head of an inkjet system and applies it to a recording medium to record an image, if the dye contains impurities, the impurities may adhere near the discharge port of the recording head. When impurities adhere near the discharge port of the recording head of the inkjet recording device, the ink droplets do not fly straight from the discharge port toward the recording medium, so the droplets are not applied to the designated position on the recording medium, and defects such as white streaks and blurs occur in the image. Therefore, as a dye used in an inkjet recording device, usually, a purification process is performed, and a dye with few impurities as described above is used.

[0006] In the dye purification process, there is a method of controlling the amount of impurities by measuring surface tension. The surface tension of an aqueous dye solution is easily affected by impurities, and if impurities are present in the aqueous dye solution, the surface tension decreases. Therefore, by measuring the surface tension of the aqueous dye solution, the amount of impurities can be controlled.

[0007] Methods for measuring the surface tension of aqueous dye solutions include the plate method (Wilhelmi method), the ring method (Dunouy method), the pendant drop method, the bubble pressure method, and the capillary rise method. Among these, the plate method is a technique that determines the surface tension from the force acting on a plate-shaped measuring probe, such as a platinum plate, when it is brought into contact with the surface of the liquid being measured (see Patent Document 1). Due to its high measurement accuracy, it is used in various fields. Furthermore, a characteristic of the plate method for measuring surface tension is that it does not require the density value of the liquid being measured (hereinafter also referred to as the measuring liquid). [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2001-99772 [Overview of the project] [Problems that the invention aims to solve]

[0009] In a surface tension measuring device equipped with the plate method described above, a series of steps can be performed automatically: supplying the measuring liquid into the device, measuring the surface tension of the measuring liquid using the plate method, cleaning the measuring probe used for measurement, and confirming the cleanliness of the cleaned measuring probe. However, a surface tension measuring device that can be attached to a purification device to automatically measure surface tension in-line and feed the results back into the purification process conditions has not been realized until now.

[0010] When the above-mentioned supply of the measuring liquid into the device, measurement of the surface tension of the measuring liquid using the plate method, cleaning of the measuring probe used for measurement, and confirmation of the cleanliness of the cleaned measuring probe are performed continuously and automatically, it is necessary to move the measuring probe and change its position while performing measurement, cleaning, and confirmation of cleanliness. However, as a result of our investigation, we have found that there is a problem in that the accuracy of measuring the surface tension of the measuring liquid decreases due to the vibration of the measuring probe when it is moved.

[0011] Specifically, when the probe is not vibrating, the bottom surface of the probe is parallel to the surface of the liquid being measured, allowing for accurate measurement of the position where the bottom surface of the probe and the surface of the liquid are in parallel. On the other hand, when the probe is vibrating, the bottom surface of the probe may not be parallel to the surface of the liquid, and the corner of the probe may come into contact with the surface of the liquid. In this case, the accuracy of the surface tension measurement decreases because the precise position where the bottom surface of the probe and the liquid surface are in parallel cannot be read. Furthermore, when cleanliness is checked by measuring the surface tension of water or other liquids, not only does the accuracy of the surface tension measurement of the liquid decrease as described above, but the accuracy of the cleanliness check also decreases for the same reason, leading to a further decrease in the accuracy of the surface tension measurement.

[0012] Therefore, an object of the present invention is to provide a surface tension measuring device and a surface tension measuring method that enable highly accurate measurements when a series of steps, including supplying a measuring liquid into the device, measuring the surface tension of the measuring liquid, cleaning the measuring probe used for measurement, and confirming the cleanliness of the cleaned measuring probe, are performed continuously and automatically. Another object of the present invention is to provide a purification device and a purification method using the above-mentioned surface tension measuring device. [Means for solving the problem]

[0013] In other words, the present invention provides a surface tension measuring device comprising: a first container for containing a first liquid to be measured; a supply path for supplying the first liquid into the first container; a measuring probe connected to a load cell, for measuring the surface tension of the first liquid supplied into the first container by a plate method using the measuring probe; a cleaning means for cleaning the measuring probe used for measuring the surface tension; and a second container for containing a second liquid used to confirm the cleanliness of the measuring probe cleaned by the cleaning means, wherein the surface tension measuring means is also used to measure the surface tension of the second liquid contained in the second container when confirming the cleanliness of the measuring probe, and at least one of (i) the measuring probe and (ii) the first container and the second container is configured to be movable within the surface tension measuring device, and if the measuring probe is configured to be movable, the measuring probe is provided with a vibration suppression mechanism.

[0014] Furthermore, the present invention provides a surface tension measurement method comprising the steps of: supplying a first liquid to be measured into a first container; measuring the surface tension of the first liquid supplied into the first container using a plate method with a measuring probe connected to a load cell, provided by a surface tension measuring means; cleaning the measuring probe used for measuring the surface tension; and confirming the cleanliness of the measuring probe after cleaning using a second liquid contained in a second container, wherein the surface tension measuring means is also used to measure the surface tension of the second liquid contained in the second container when confirming the cleanliness of the measuring probe, and at least one of (i) the measuring probe and (ii) the first container and the second container is configured to be movable within the surface tension measuring device, and if the measuring probe is configured to be movable, the measuring probe is provided with a vibration suppression mechanism. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a surface tension measuring device and a surface tension measuring method that enable highly accurate measurements when a series of steps, including supplying the measuring liquid into the device, measuring the surface tension of the measuring liquid, cleaning the measuring probe used for measurement, and confirming the cleanliness of the cleaned measuring probe, are performed automatically and continuously. Furthermore, according to the present invention, it is possible to provide a purification device and a purification method using the above-mentioned surface tension measuring device. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic side view showing the general configuration of the surface tension measuring device according to the first embodiment. [Figure 2] This figure shows the initial state of the surface tension measuring device shown in Figure 1. [Figure 3] This diagram illustrates the operation of the surface tension measuring device shown in Figure 1 when supplying the first liquid to the first container. [Figure 4] This diagram illustrates the operation of the surface tension measuring device shown in Figure 1 when measuring the surface tension of a first liquid. [Figure 5] This figure shows the surface tension measuring device shown in Figure 1, in the process of measuring the surface tension of the first liquid. [Figure 6] This diagram illustrates the operation of the surface tension measuring device shown in Figure 1 after the measurement of the surface tension of the first liquid. [Figure 7] This diagram illustrates the operation of cleaning the measuring probe in the surface tension measuring device shown in Figure 1. [Figure 8] This figure shows the surface tension measuring device shown in Figure 1, in the state of cleaning the measuring probe. [Figure 9] This diagram illustrates the operation of the surface tension measuring device shown in Figure 1 after the measuring probe has been cleaned. [Figure 10] This diagram illustrates the operation of checking the cleanliness of the measuring probe in the surface tension measuring device shown in Figure 1. [Figure 11] This figure shows the surface tension measuring device shown in Figure 1, in the process of measuring the surface tension of the second liquid. [Figure 12] It is a side schematic view showing a schematic configuration of the surface tension measuring device of the second embodiment. [Figure 13] It is a side schematic view showing a schematic configuration of the surface tension measuring device of the third embodiment. [Figure 14] It is a side schematic view showing a schematic configuration of the purification device of the fourth embodiment. [Figure 15] It is a side schematic view showing a schematic configuration of the surface tension measuring device of the comparative example.

Embodiments for Carrying Out the Invention

[0017] <Surface Tension Measuring Device> The surface tension measuring device of one embodiment of the present invention includes a first container, a supply path, a surface tension measuring means, a cleaning means, and a second container. The first container is a container that houses the first liquid to be measured. The supply path is a flow path for supplying the first liquid into the first container. The surface tension measuring means has a measuring element connected to a load cell, and is a means for measuring the surface tension of the first liquid supplied into the first container by the plate method using the measuring element. The cleaning means is a means for cleaning the measuring element used for measuring the surface tension. The second container is a container that houses the second liquid. The second liquid is a liquid used for confirming the cleanliness of the measuring element cleaned by the cleaning means.

[0018] In the surface tension measuring device of the present embodiment, in addition to being used for measuring the surface tension of the first liquid, the above surface tension measuring means is further used for measuring the surface tension of the second liquid housed in the second container when confirming the cleanliness of the measuring element. Also, in the surface tension measuring device of the present embodiment, at least one of (i) the measuring element and (ii) the first container and the second container is configured to be movable within the surface tension measuring device. And when the measuring element is configured to be movable, the measuring element is provided with a vibration suppression mechanism.

[0019] In this disclosure, the fact that the measuring probe, the first container, and the second container are movable means that they can move in a parallel and vertical direction with respect to the liquid level of the first liquid in the first container provided in the surface tension measuring device. Examples of moving means include movable stages with two or more axes.

[0020] The surface tension measuring device of this embodiment is suitably used when a series of steps, including supplying a first liquid to a first container, measuring the surface tension of the first liquid, cleaning the measuring probe used for the measurement, and confirming the cleanliness of the cleaned measuring probe, are performed automatically and continuously. When the above series of steps are performed automatically and continuously, the surface tension of the first liquid supplied into the device can be measured while the vibration of the measuring probe is suppressed, and the cleanliness of the measuring probe after cleaning can be confirmed, thus providing a surface tension measuring device capable of highly accurate measurements. Furthermore, this surface tension measuring device can be used for in-line automated analysis, and a purification apparatus equipped with this surface tension measuring device can improve productivity.

[0021] A preferred embodiment of the surface tension measuring device described above will be explained below with reference to the attached drawings. Although several features are described in the embodiment, not all of these features are necessarily essential to the invention, and the features may be combined in any way. Furthermore, in the attached drawings, the same or similar configurations are given the same reference numeral, and redundant descriptions are omitted.

[0022] In this specification and the accompanying drawings, directions are indicated using an XYZ coordinate system, where the Z-axis is perpendicular to the surface of the first liquid in the first container of the surface tension measuring device, and the X-axis and Y-axis are two mutually orthogonal directions parallel to the plane perpendicular to the Z-axis. The directions along the X-axis, Y-axis, and Z-axis may also be described as the X direction, Y direction, and Z direction, respectively. The X and Y directions are parallel to the surface of the first liquid in the first container of the surface tension measuring device, with the X direction being the left-right direction in the drawing and the Y direction being perpendicular to the drawing. In the Z direction, the direction upward in the drawing may be described as the +Z direction, and the direction downward in the drawing may be described as the -Z direction.

[0023] [First Embodiment] Figure 1 is a schematic side view showing the general configuration of the surface tension measuring device 100 of the first embodiment. The surface tension measuring device 100 of the first embodiment comprises a first container 11, a supply passage 16, a surface tension measuring means having a measuring probe 19, a cleaning means 17 for cleaning the measuring probe 19, and a second container 12. The surface tension measuring device 100 is an example of a configuration in which (i) the measuring probe 19 does not move, and (ii) the first container 11 and the second container 12 are movable. In the surface tension measuring device 100, since the measuring probe 19 does not move, a vibration suppression mechanism is not provided, but a vibration suppression mechanism may be provided to suppress vibrations from the outside.

[0024] (Transfer of the first and second containers) In the surface tension measuring device 100 of the first embodiment, the first container 11, the second container 12, and the cleaning means 17 are mounted on a movable stage 10 that can move along two or more axes. The movable stage 10 moves at least in the horizontal X-axis direction and the vertical Z-axis direction with respect to the liquid surface of the first liquid 13 contained in the first container 11. The movable stage 10 may also move in the Y-axis direction, which is horizontal with respect to the liquid surface of the first liquid 13 contained in the first container 11.

[0025] (Exterior cover) It is preferable that the surface tension measurement using the surface tension measuring device 100 is performed inside the outer cover 1 so that the measuring probe 19 and the liquids used to measure surface tension (first liquid 13 and second liquid 14) are less susceptible to the effects of wind outside the device, at least during the surface tension measurement. By using the outer cover 1 at least during the surface tension measurement, the measuring probe 19 and the measuring liquids such as the first liquid 13 are less susceptible to the effects of wind from the outside and less prone to vibrations caused by wind, thereby improving the accuracy of surface tension measurement.

[0026] As the outer cover 1, a cover member that covers the measuring probe 19, the first container 11, the second container 12, the cleaning means 17, and the movable stage 10 on which they are installed can be suitably used. Alternatively, the outer cover 1 may be placed on a vibration isolation table to suppress external vibrations and reduce the influence of vibrations outside the device on the measuring probe 19, or a temperature control function may be provided to control the temperature of the measurement environment. Since surface tension is affected by the temperature of the liquid being measured (first liquid 13 and second liquid 14), controlling the temperature will enable more accurate measurements.

[0027] (First container) The first container 11 is a container for holding the first liquid 13. There may be one or more first containers 11. The first liquid 13 is the liquid whose surface tension is to be measured. The first liquid 13 is a liquid supplied to the first container 11 from an external source for the purpose of measuring surface tension. It may be any liquid, including water-containing liquid compositions such as aqueous solutions, or liquid compositions containing organic solvents.

[0028] (Second container) The second container 12 is a container for holding the second liquid 14. There may be one or more second containers 12. The second liquid 14 is a liquid used to check the cleanliness of the measuring probe 19 after washing. The second liquid 14 may be contained in the second container 12 from the beginning, or a means for supplying the second liquid 14 may be provided to supply the second liquid 14 to the second container 12 at the necessary timing.

[0029] (supply route) The first liquid 13 is supplied into the first container 11 through the supply passage 16. The method of supplying the first liquid 13 can be as follows: if supplied from a pressurized pipe, a valve can be installed and opened / closed to control the pressure; or, as shown in Figure 1, a pump 15 can be used. Using a pump 15 is preferable from the viewpoint of easily controlling the amount and speed of liquid supplied.

[0030] (pump) As described above, the surface tension measuring device 100 may be equipped with a pump 15. The pump 15 can supply the first liquid 13 into the first container 11 through the supply passage 16. The type of pump 15 is not particularly limited, but from the viewpoint of high accuracy in liquid delivery speed and volume, it is preferable to use a syringe pump.

[0031] (Surface tension measurement means) The surface tension measuring device 100 comprises a surface tension measuring means having a measuring probe 19 connected to a load cell 18. The surface tension measuring means is a means for measuring the surface tension of a first liquid 13 supplied into a first container 11 by the plate method using the measuring probe 19.

[0032] Surface tension is measured using a surface tension measuring device by the plate method. The measurement of surface tension by the plate method is based on Wilhelmi's principle. According to this principle, when the measuring probe comes into contact with the surface of the liquid being measured, the probe is drawn into the liquid, and in that state, the following relationship (1) holds true. F = mg + Lγ - shρg ···(1) In equation (1) above, F is the force that pulls the probe in, m is the mass of the probe, g is the acceleration due to gravity, L is the circumference of the probe, γ is the surface tension, s is the cross-sectional area of ​​the probe, h is the distance from the bottom of the probe to the liquid surface, and ρ is the density of the liquid being measured.

[0033] In the measurement of surface tension using the plate method described above, if the measuring probe is raised until h in equation (1) becomes 0, F = mg + Lγ Therefore, the surface tension γ is, γ = (F - mg) / L It can be calculated using this method. Thus, in the plate method, surface tension can be calculated without using the density of the measurement solution when measuring at the h=0 position. Therefore, in measuring the surface tension of an aqueous dye solution in a purification process that has density variations due to variations in dye concentration, the plate method can measure surface tension with greater accuracy than the other measurement methods mentioned above.

[0034] (Measuring element) The material of the measuring probe 19 is not particularly limited, but it is preferably made of platinum or glass from the viewpoint that its surface properties are less likely to change due to chemical reactions. The shape of the measuring probe 19 is a plate, and it is structured so that its bottom surface is horizontal when connected to the load cell 18. If the bottom surface of the measuring probe 19 is not horizontal, it becomes difficult to accurately measure the surface tension.

[0035] In the aforementioned formula for calculating surface tension, the value of F at the position where h=0 is required for the calculation. That is, the position where the bottom surface of the measuring probe 19 contacts the surface of the liquid being measured when the bottom surface of the measuring probe 19 is perfectly horizontal. If the bottom surface of the measuring probe 19 is perfectly horizontal, this position can be determined from the change in the measured value of the load cell 18 at the moment it contacts the liquid surface. On the other hand, if the bottom surface of the measuring probe 19 is not horizontal, the corner (edge) of the bottom surface of the measuring probe 19 will first contact the liquid surface. Therefore, if this position is recognized as the position where h=0, a difference will arise between this position and the position where the bottom surface of the measuring probe 19 contacts the liquid surface when the bottom surface of the measuring probe 19 is perfectly horizontal, making it difficult to accurately measure the surface tension. Furthermore, if the measuring probe 19 is vibrating during surface tension measurement, the bottom surface of the measuring probe 19 may not contact the liquid surface even when the bottom surface of the measuring probe 19 is perfectly horizontal, making it difficult to accurately measure the surface tension.

[0036] (Load cell) The surface tension measuring device 100 may include a load cell 18 provided on the surface tension measuring means. The load cell 18 measures the mass of the measuring probe 19 and the force that pulls the measuring probe 19 in. The load cell 18 is not particularly limited, but from the viewpoint of high measurement accuracy, it is preferable to use an electronic balance capable of underfloor weighing.

[0037] (Cleaning method) The surface tension measuring device 100 includes a cleaning means 17 for cleaning the measuring probe 19 used to measure surface tension. The cleaning means 17 is a means for removing impurities adhering to the measuring probe 19 after surface tension measurement. Therefore, it is preferable to appropriately select a suitable cleaning means 17 depending on the object to be measured. Examples of cleaning means 17 include cleaning liquids and heat, and multiple types of cleaning means may be used in combination. Preferably, the cleaning means 17 is a cleaning means that cleans the measuring probe 19 using at least one selected from the group consisting of heat, water, and organic solvents.

[0038] If the first liquid 13 to be measured contains an aqueous liquid, it is preferable to wash the measuring element 19 with water as the washing solution. If the first liquid 13 contains an organic solvent liquid, it is preferable to wash the measuring element 19 with an organic solvent as the washing solution. Furthermore, if the first liquid 13 contains insoluble impurities, it is preferable to wash the measuring element 19 by using heat as the washing means 17 to thermally decompose the insoluble impurities attached to it. Multiple types of these washing means 17 may be used in combination.

[0039] When a cleaning solution such as water or an organic solvent is used as the cleaning means 17, for example, a cleaning container and the cleaning solution contained in the cleaning container can be used. The measuring probe 19 can be cleaned by immersing the measuring probe 19 in the cleaning solution contained in the cleaning container, using the cleaning solution contained in the cleaning container as the cleaning means 17. The cleaning solution may be contained in the cleaning container from the beginning, or a means for supplying the cleaning solution may be provided to supply the cleaning solution to the cleaning container at the necessary timing. Water or an alcohol-based solvent is preferred as the cleaning solution. From the viewpoint of safety, ethanol or isopropyl alcohol is more preferred as the alcohol-based solvent. The surface tension measuring device 100 may be equipped with multiple cleaning containers depending on the type of cleaning solution that can be used, so that an appropriate cleaning means 17 can be selected depending on the type of first liquid 13 to be measured.

[0040] When heat is used as the cleaning means 17, the cleaning means using heat is not particularly limited, but from a safety standpoint, a small electric furnace capable of heating the measuring element 19 electrically is preferred.

[0041] The cleaning means 17 is preferably installed on the movable stage 10 together with the first container 11 and the second container 12. The aforementioned cleaning container when a cleaning liquid is used as the cleaning means 17, or the aforementioned small electric furnace when heat is used as the cleaning means 17, can be installed on the movable stage 10. In the surface tension measuring device 100 of the first embodiment, a cleaning container 17b containing water 17a, which is the cleaning liquid used as the cleaning means 17, is installed on the movable stage 10 (see Figure 2).

[0042] When the measuring probe 19 is cleaned with the cleaning solution described above, it is preferable to dry the measuring probe 19 before proceeding with the next operation in order to ensure that no cleaning solution remains on the measuring probe 19 so that accurate measurements can be obtained in the next surface tension measurement. As a means of drying the measuring probe 19 after cleaning, the cleaning solution adhering to the measuring probe 19 may be vaporized or evaporated by using a blower to blow air onto the measuring probe 19 or a heating device to heat the measuring probe 19, or it may be allowed to air dry naturally over time. Whether or not the measuring probe 19 is dry can be determined by measuring the mass of the measuring probe 19 with the load cell 18. If it is not completely dry, the mass will be greater than the original mass of the measuring probe 19.

[0043] (Checking cleanliness) The cleanliness of the measuring probe 19, which has been cleaned by the cleaning means 17 described above, is confirmed by measuring the surface tension of a second liquid 14, which is a liquid with a known surface tension. If the measuring probe 19 is sufficiently cleaned, the surface tension will be a known value. It is preferable to use water as the second liquid 14, which is a liquid with a known surface tension. That is, it is preferable that the second liquid 14 is water, and that the cleanliness is confirmed by measuring the surface tension of the water as the second liquid 14. Since the surface tension of water is greatly affected by impurities, by measuring the surface tension of water to confirm the cleanliness of the measuring probe 19 after cleaning, a highly accurate confirmation of cleanliness can be performed.

[0044] (Automatic measurement) The surface tension measuring device 100 can automatically perform a series of operations, including supplying the first liquid 13 to the first container 11, measuring the surface tension of the first liquid 13, cleaning the measuring probe 19 used for the measurement with the cleaning means 17, and confirming the cleanliness of the measuring probe 19 after cleaning. In other words, the first liquid 13 can be automatically supplied to the first container 11 of the surface tension measuring device 100 from an external device. Furthermore, the surface tension of the first liquid 13 supplied to the first container 11 can be automatically measured using the plate method, and the measuring probe 19 used for the measurement can be automatically cleaned with the cleaning means 17. In addition to these operations, the device can automatically confirm the cleanliness of the cleaned measuring probe 19, enabling it to be ready for the next measurement, and all of these processes can be performed continuously and automatically.

[0045] Furthermore, when checking the cleanliness of the measuring probe 19, if the cleanliness of the measuring probe 19 is insufficient, the cleaning means 17 can be used to clean the measuring probe 19 again, and this process can be automatically repeated until the cleanliness is sufficient.

[0046] When performing continuous automatic surface tension measurements, multiple first containers 11 for holding the measuring liquid may be provided, allowing the measuring liquid to be supplied to a different container each time. Alternatively, a mechanism may be provided to discharge the liquid from the first container 11 when the measurement is complete, and the supply and discharge of the next measuring liquid may be automatically repeated several times to replace the liquid in the first container 11 with the next measuring liquid. Similarly, multiple containers for holding the second liquid 14 or the cleaning liquid used as a cleaning means 17 may be provided, or the liquids may be changed at any time.

[0047] [Operation of the first embodiment] Next, with reference to Figures 2 to 11, the operation of the surface tension measuring device 100 according to the first embodiment will be described as an example of the operation of the series of steps described above, and the method for measuring surface tension by that operation. Figures 2 to 11 are schematic side views illustrating an example of the operation of the surface tension measuring device 100 in the schematic configuration of the surface tension measuring device 100 according to the first embodiment. The dashed arrows in Figures 4 to 11 indicate the direction of movement of the movable stage 10.

[0048] (Initial state) Figure 2 is a schematic side view showing the initial state of the surface tension measuring device 100. The surface tension measuring device 100 comprises a first container 11 for containing a first liquid 13, a second container 12 for containing a second liquid 14, and a cleaning means 17 (a cleaning container 17b containing cleaning liquid 17a) within an outer cover 1, as well as a movable stage 10 on which these are installed. The surface tension measuring device 100 also includes a surface tension measuring means having a supply passage 16 for supplying the first liquid 13 into the first container 11, a load cell 18, and a measuring probe 19 connected to the load cell 18. Furthermore, the surface tension measuring device 100 includes the first liquid 13 and a pump 15 for supplying the first liquid 13 outside the outer cover 1.

[0049] (Supply of the first liquid) First, the surface tension measuring device 100 is used to supply the first liquid 13, which is to be measured, into the first container 11 from outside the device. Specifically, as shown in Figure 3, with the first container 11 positioned directly below the liquid outlet of the supply passage 16, the pump 15 is used to send the first liquid 13 to the first container 11 through the supply passage 16. If the first container 11 is not positioned directly below the liquid outlet of the supply passage 16, the movable stage 10 is used to move the first container 11 to directly below the liquid outlet of the supply passage 16.

[0050] (Moving the first container) After supplying the first liquid 13 into the first container 11, the process proceeds to measuring the surface tension of the first liquid 13 in the first container 11 using a surface tension measuring device. When measuring the surface tension of the first liquid 13, as shown in Figure 4, the movable stage 10 on which the first container 11 is installed is moved in the horizontal X direction (+X direction in the figure) so that the first container 11 is positioned directly below the measuring probe 19. At this time, the movable stage 10 may also be moved in the horizontal Y direction so that the first container 11 is positioned directly below the measuring probe 19.

[0051] (Measurement of the surface tension of the first liquid) The first step involves measuring the surface tension of the first liquid 13 supplied to the first container 11 using the plate method with a measuring probe 19 connected to a load cell 18, which is provided by a surface tension measuring means. In this step, the first container 11 containing the first liquid 13 is placed directly below the measuring probe 19, and then, as shown in Figure 5, the movable stage 10 is raised vertically (in the +Z direction in the figure). This brings the measuring probe 19 into contact with the surface of the first liquid 13 in the first container 11, and the surface tension of the first liquid 13 is measured using the plate method.

[0052] (Movement of the movable stage) After measuring the surface tension of the first liquid 13 using the surface tension measuring means equipped with the measuring probe 19, the movable stage 10 is lowered vertically (in the -Z direction in the figure) as shown in Figure 6. Next, the process proceeds to cleaning the measuring probe 19 used to measure the surface tension. When cleaning the measuring probe 19, first, the movable stage 10 is moved horizontally (in the -X direction in the figure) so that the cleaning means 17 is positioned directly below the measuring probe 19, as shown in Figure 7.

[0053] (Cleaning of the measuring element) A step is performed to clean the measuring probe 19 used to measure the surface tension. In this step, a cleaning means 17 is placed directly below the measuring probe 19, and then, as shown in Figure 8, the measuring probe 19 used to measure the surface tension of the first liquid 13 is cleaned by the cleaning means 17. When a cleaning solution 17a contained in a cleaning container 17b is used as the cleaning means 17, the measuring probe 19 can be cleaned by raising the movable stage 10 vertically (in the +Z direction in the figure) and immersing the measuring probe 19 in the cleaning solution 17a. At this time, the cleaning effect of the measuring probe 19 can be enhanced by moving the movable stage 10 up and down in small increments in the vertical direction (in the +Z and -Z directions in the figure).

[0054] (Movement of the movable stage) After cleaning the measuring probe 19 with the cleaning means 17, the movable stage 10 is lowered vertically (in the -Z direction in the figure) as shown in Figure 9. Next, the process proceeds to confirm the cleanliness of the cleaning measuring probe 19. To confirm the cleanliness of the measuring probe 19, first, as shown in Figure 10, the movable stage 10 is moved horizontally in the X direction (in the -X direction in the figure) so that the second container 12 containing the second liquid 14 is positioned directly below the measuring probe 19.

[0055] (Checking cleanliness) A step is performed to check the cleanliness of the measuring probe 19 after cleaning using the second liquid 14 contained in the second container 12. In this step, the second container 12 containing the second liquid 14 is placed directly below the measuring probe 19, and then the movable stage 10 is raised vertically (in the +Z direction in the figure) as shown in Figure 11. This brings the measuring probe 19 into contact with the liquid surface of the second liquid 14 in the second container 12, and the surface tension of the second liquid 14 is measured by the plate method, thereby confirming the cleanliness of the measuring probe 19. If the cleanliness of the measuring probe 19 is insufficient, the cleaning of the measuring probe 19 using the cleaning means 17 (see Figure 8) and the confirmation of the cleanliness of the measuring probe 19 using the second liquid 14 (see Figure 11) can be repeated by moving the movable stage 10 horizontally and vertically.

[0056] (Transition to initial state) After confirming the cleanliness of the measuring probe 19, the movable stage 10 is lowered vertically (in the -Z direction in the figure) and then moved horizontally (in the +X direction in the figure) to return the surface tension measuring device 100 to its initial state (see Figures 2 and 3). After confirming the cleanliness of the measuring probe 19, if necessary, the second liquid 14 adhering to the measuring probe 19 may be vaporized or evaporated by means of drying the measuring probe 19 or by natural drying.

[0057] In the surface tension measuring device 100 of the first embodiment, the above series of steps can be performed continuously without moving the measuring probe 19 by moving the first container 11 and the second container 12, thus making it possible to suppress vibration of the measuring probe 19. Therefore, when the above series of steps are performed continuously and automatically using the surface tension measuring device 100 of the first embodiment, highly accurate surface tension measurement is possible.

[0058] In another embodiment of the present invention, the movable stage 10 can be operated so that the positional relationship between the liquid outlet of the supply passage 16, the measuring probe 19, the first container 11, the second container 12, and the cleaning means 17 is the same as in the operation flow described above. This makes it possible to perform a series of operations in the other embodiment as well, including supplying the first liquid 13, measuring the surface tension, cleaning the measuring probe 19, and confirming the cleanliness.

[0059] [Second Embodiment] Figure 12 is a schematic side view showing the general configuration of the surface tension measuring device 200 of the second embodiment. The surface tension measuring device 200 of the second embodiment differs from the surface tension measuring device 100 of the first embodiment in that (ii) the first container 11 and the second container 12 do not move within the surface tension measuring device 200, and (i) the measuring probe 19 is configured to be movable. Furthermore, since the measuring probe 19 of the second embodiment is configured to be movable, the surface tension measuring device 200 also differs from the surface tension measuring device 100 of the first embodiment in that the measuring probe 19 is equipped with a vibration suppression mechanism 21. In addition, the surface tension measuring device 200 of the second embodiment also differs from the surface tension measuring device 100 of the first embodiment in that it is equipped with a small electric furnace 17c as a cleaning means 17 that can heat the measuring probe 19 by electricity. The following describes the differences between the surface tension measuring device 200 of the second embodiment and the surface tension measuring device 100 of the first embodiment described above, and the same configuration as the surface tension measuring device 100 of the first embodiment will not be described.

[0060] The surface tension measuring device 200 of the second embodiment includes, within the outer cover 1, a first container 11 for containing the first liquid 13, a second container 12 for containing the second liquid 14, a supply passage 16 for the first liquid 13, and a cleaning means 17 (small electric furnace 17c). The surface tension measuring device 200 includes a non-movable stage 20, on which the first container 11, the second container 12, and the cleaning means 17 are arranged. The surface tension measuring device 200 also includes, within the outer cover 1, a load cell 18, a measuring probe 19 connected to the load cell 18, a movable stage 10 to which the load cell 18 is fixed, and a vibration suppression mechanism 21 capable of suppressing vibration of the measuring probe 19. Furthermore, outside the outer cover 1, the surface tension measuring device 200 includes the first liquid 13 and a pump 15 for supplying the first liquid 13.

[0061] (Movement of the measuring probe) In the surface tension measuring device 200, the load cell 18 is mounted on a movable stage 10 that can move along two or more axes. The movable stage 10 moves at least in the horizontal X-axis direction and the vertical Z-axis direction with respect to the liquid surface of the first liquid 13 contained in the first container 11. The movable stage 10 may also move in the Y-axis direction, which is horizontal with respect to the liquid surface of the first liquid 13 contained in the first container 11. In the surface tension measuring device 200, since the load cell 18 is fixed to the movable stage 10, the measuring probe 19 connected to the load cell 18 is configured to be movable.

[0062] (Vibration suppression mechanism) The vibration suppression mechanism 21 is provided when the measuring element 19 is configured to be movable. The vibration suppression mechanism 21 is a mechanism capable of suppressing vibration of the measuring element 19. Preferably, the vibration suppression mechanism 21 is a mechanism that provides a support body that can suppress vibration by contacting the measuring element 19 when it vibrates, either on the measuring element 19 or at the point between the measuring element 19 and the load cell 18. The contact point between the support body and the measuring element 19, or the point between the measuring element 19 and the load cell 18, may be one point or more.

[0063] On the other hand, in the surface tension measuring device 100 of the first embodiment shown in Figure 1, the load cell 18 to which the measuring probe 19 is connected is fixed so as not to move, and the first container 11 and the second container 12 are moved. Therefore, although the movement of the first container 11 and the second container 12 causes slight fluctuations in the liquid surface of the liquid contained in each container, these fluctuations are far smaller than the vibration of the measuring probe 19 when the measuring probe 19 is moved, and their effect on the measurement of surface tension becomes negligible. Thus, the surface tension measuring device 100 of the first embodiment can measure surface tension accurately even without a vibration suppression mechanism.

[0064] [Operation of the second embodiment] Next, we will describe the differences in operation between the surface tension measuring device 200 of the second embodiment and the surface tension measuring device 100 of the first embodiment described above, as an example of the operation of the second embodiment.

[0065] (Supply of the first liquid) First, the first liquid 13 is supplied into the first container 11 from outside the surface tension measuring device 200. As shown in Figure 12, with the first container 11 positioned below the liquid outlet of the supply passage 16, the first liquid 13 is sent by the pump 15 and supplied to the first container 11 through the supply passage 16. In the surface tension measuring device 200, since the first container 11 and other components are provided on the non-movable stage 20, the first container 11 can be positioned below the liquid outlet of the supply passage 16 in the initial state of the surface tension measuring device 200.

[0066] (Movement of the measuring probe) After supplying the first liquid 13 into the first container 11, the process proceeds to measuring the surface tension of the first liquid 13 in the first container 11 using a surface tension measuring means. To measure the surface tension of the first liquid 13, the movable stage 10 to which the load cell 18, to which the measuring probe 19 is attached, is moved in the horizontal X direction (-X direction in the figure) so that the measuring probe 19 is positioned above the first container 11 containing the first liquid 13. At this time, the movable stage 10 may also be moved in the horizontal Y direction so that the measuring probe 19 is positioned directly above the first container 11.

[0067] (Measurement of the surface tension of the first liquid) The movable stage 10 is moved to position the measuring probe 19 above the first container 11, and then the movable stage 10 is lowered vertically (in the -Z direction in the figure). This brings the measuring probe 19 into contact with the surface of the first liquid 13 in the first container 11, and the surface tension of the first liquid 13 is measured using the plate method. When the movable stage 10 is moved horizontally (in the -X direction in the figure) and vertically (in the -Z direction in the figure), the vibration of the measuring probe 19 is suppressed by the vibration suppression mechanism 21, thereby improving the accuracy of the measurement of the surface tension of the first liquid 13.

[0068] (Movement of the movable stage) After measuring the surface tension of the first liquid 13 using the surface tension measuring means equipped with a measuring probe 19, the movable stage 10 is raised vertically (in the +Z direction in the figure). Next, the process proceeds to cleaning the measuring probe 19 used to measure the surface tension. To clean the measuring probe 19, the movable stage 10 is moved horizontally (in the +X direction in the figure) so that the measuring probe 19 is positioned above the cleaning means 17.

[0069] (Cleaning of the measuring element) After placing the measuring probe 19 on the cleaning means 17, the measuring probe 19 used to measure the surface tension of the first liquid 13 is cleaned by the cleaning means 17. In this case, if the small electric furnace 17c described above is used as the cleaning means 17, the movable stage 10 does not need to be lowered vertically (in the -Z direction in the figure) if sufficient heat from the small electric furnace 17c is applied to the measuring probe 19. Alternatively, in order to enhance the cleaning effect of the measuring probe 19, the movable stage 10 may be lowered vertically (in the -Z direction in the figure) so that the measuring probe 19 is closer to the small electric furnace 17c.

[0070] (Movement of the movable stage) After cleaning the measuring probe 19 with the cleaning means 17, the process proceeds to the step of checking the cleanliness of the cleaning measuring probe 19. To check the cleanliness of the measuring probe 19, the movable stage 10 is moved in the horizontal direction, the X direction (+X direction in the figure), so that the measuring probe 19 is positioned above the second container 12 containing the second liquid 14.

[0071] (Checking cleanliness) After positioning the measuring probe 19 above the second container 12 containing the second liquid 14, the movable stage 10 is lowered vertically (in the -Z direction in the figure). This brings the measuring probe 19 into contact with the surface of the second liquid 14 in the second container 12, allowing the surface tension of the second liquid 14 to be measured by the plate method, thereby confirming the cleanliness of the measuring probe 19. When moving the movable stage 10 horizontally (in the +X direction in the figure) and vertically (in the -Z direction in the figure), the vibration of the measuring probe 19 is suppressed by the vibration suppression mechanism 21, thereby improving the accuracy of the measurement of the surface tension of the second liquid. If the cleanliness of the measuring probe 19 is insufficient, the cleaning of the measuring probe 19 using the cleaning means 17 and the confirmation of the cleanliness of the measuring probe 19 using the second liquid 14 can be repeatedly performed by moving the movable stage 10 horizontally and vertically.

[0072] (Transition to initial state) After confirming the cleanliness of the measuring probe 19, the movable stage 10 is raised vertically (in the +Z direction in the figure) and then moved horizontally (in the -X direction in the figure) to return the surface tension measuring device 200 to its initial state (see Figure 12).

[0073] In the surface tension measuring device 200 of the second embodiment, as the movable stage 10 to which the load cell 18 is fixed moves horizontally and vertically, the measuring probe 19 connected to the load cell 18 also moves horizontally and vertically. During the horizontal and vertical movement of the measuring probe 19, the measuring probe 19 is equipped with a vibration suppression mechanism 21, so that vibration of the measuring probe 19 can be suppressed. Therefore, with the surface tension measuring device 200 of the second embodiment, highly accurate surface tension measurement is possible when the above series of steps are performed continuously and automatically.

[0074] [Third Embodiment] Figure 13 is a schematic side view showing the general configuration of the surface tension measuring device 300 of the third embodiment. The surface tension measuring device 300 of the third embodiment differs from the first and second embodiments in that (i) the measuring probe 19 and (ii) the first container 11 and the second container 12 are configured to be movable within the surface tension measuring device 300. The surface tension measuring device 300 of the third embodiment also differs from the first and second embodiments in that it includes a cleaning container 17b containing ethanol 17d, which is a cleaning solution, as a cleaning means 17. Below, the differences between the surface tension measuring device 300 of the third embodiment and the surface tension measuring devices 100 and 200 of the first and second embodiments described above will be explained, and similar configurations will not be described.

[0075] (composition) The surface tension measuring device 300 of the third embodiment includes, within the outer cover 1, a first container 11 for containing a first liquid 13, a second container 12 for containing a second liquid 14, a supply passage 16 for the first liquid 13, and a cleaning means 17. The surface tension measuring device 300 also includes a movable stage 10 (10A) on which the first container 11, the second container 12, and the cleaning means 17 are provided. The first container 11, the second container 12, and the cleaning means 17 are configured to be movable by being installed on the movable stage 10A.

[0076] The surface tension measuring device 300 includes, within the outer cover 1, a load cell 18, a measuring probe 19 connected to the load cell 18, a movable stage 10 (10B) to which the load cell 18 is fixed, and a vibration suppression mechanism 21 capable of suppressing vibration of the measuring probe 19. The measuring probe 19 is configured to be movable because it is connected to the load cell 18 and the load cell 18 is fixed to the movable stage 10B. Furthermore, outside the outer cover 1, the surface tension measuring device 300 includes a first liquid 13 and a pump 15 for supplying the first liquid 13.

[0077] (operation) In the surface tension measuring device 300 of the third embodiment, the first container 11, the second container 12, and the cleaning means 17 are configured to be movable, so it is possible to perform operations similar to those of the surface tension measuring device 100 of the first embodiment. Furthermore, in the surface tension measuring device 300 of the third embodiment, the measuring probe 19 is also configured to be movable, so it is possible to perform operations similar to those of the surface tension measuring device 200 of the second embodiment. Moreover, in the surface tension measuring device 300 of the third embodiment, the measuring probe 19, as well as the first container 11 and the second container 12, are all configured to be movable, so it is possible to perform operations that appropriately combine the operations described in the first and second embodiments.

[0078] The surface tension measuring device 300 of the third embodiment can also perform the same operations as the first and second embodiments, so when the above-described series of steps are performed automatically in a continuous manner, highly accurate surface tension measurement is possible. In the surface tension measuring device 300 of the third embodiment, for example, when the above-described series of steps are performed by moving the first container 11 and the second container 12, etc., without moving the measuring probe 19, the vibration suppression mechanism 21 can suppress the shaking of the measuring probe 19 due to external vibrations and wind. Therefore, it is expected that the accuracy of surface tension measurement will be further improved.

[0079] [Other components] The surface tension measuring devices 100, 200, and 300 of each embodiment described above may include a control unit including a CPU that automatically executes a series of processes, including the operation of the movable stage 10 described above. The control unit can be communicated with the movable stage 10, load cell 18, pump 15, etc. In addition to the CPU, the control unit may also include ROM, RAM, and storage. For example, the CPU can be configured to execute the series of processes described above by loading a computer program corresponding to the operation of the series of processes stored in ROM or storage into RAM and executing it.

[0080] <Purification equipment> A purification apparatus according to one embodiment of the present invention includes a surface tension measuring device according to the present invention described above. This purification apparatus is configured to feed back the surface tension of a first liquid measured by the surface tension measuring device to the purification processing conditions. Furthermore, a purification method according to one embodiment of the present invention includes a step of feeding back the surface tension of a first liquid measured by the surface tension measuring device to the purification processing conditions.

[0081] In this disclosure, a purification apparatus is a device capable of removing impurities from a solution. Examples of purification methods for removing impurities include methods of adsorption removal using activated carbon, zeolite, or silica gel, and methods of filtering out impurities using filtration methods such as ultrafiltration and nanofiltration. As mentioned above, it is preferable to use an aqueous solution of dye as the solution, and the purification apparatus is preferably a purification apparatus for the aqueous solution of dye.

[0082] [Fourth Embodiment] An example of a purification apparatus will be described below with reference to Figure 14. Figure 14 is a schematic side view showing the general configuration of the purification apparatus 400 of the fourth embodiment. In Figure 14, a configuration in which the purification apparatus 400 is equipped with the surface tension measuring device 100 of the first embodiment described above is illustrated. This purification apparatus 400 may also be equipped with the surface tension measuring device 200 of the second embodiment or the surface tension measuring device 300 of the third embodiment instead of the surface tension measuring device 100 of the first embodiment.

[0083] The purification apparatus 400 includes a purification processing unit 50, a surface tension measuring device 100 that supplies a measuring liquid (first liquid) from the purification processing unit 50 to the surface tension measuring device 100 to measure the surface tension, and a signal line 60 that transmits the measured surface tension to the purification processing unit 50.

[0084] The surface tension measuring device 100 is connected to the purification processing unit 50, and the measuring liquid (first liquid) in the purification processing unit 50 is supplied to the first container 11 in the surface tension measuring device 100 through the supply passage 16 by the pump 15, and the surface tension is measured by the operation described above. As mentioned above, in the surface tension measuring device 100, a series of processes can be carried out continuously without moving the measuring probe 19 by moving the first container 11, the second container 12, and the washing means 17. Therefore, it is possible to suppress vibration of the measuring probe 19, and highly accurate surface tension measurement is possible. In the purification apparatus 400, it is also possible to configure the measuring probe 19 to be movable, and if the measuring probe 19 is configured to be movable, highly accurate surface tension measurement is possible by providing a vibration suppression mechanism to the measuring probe 19.

[0085] The purification unit 50 is a device that purifies the measurement solution, such as an aqueous dye solution, by the purification method described above. In the purification device 400, instead of transmitting the surface tension measurement value to the purification unit 50 via the signal line 60, the measurement value of the load cell 18 may be transmitted directly to the purification unit 50 via the signal line 60 and converted into a surface tension value in the purification unit 50.

[0086] As described above, by transmitting surface tension measurements and load cell measurements to the purification processing unit 50, the measured surface tension can be fed back into the purification processing conditions, enabling purification to be performed under appropriate processing conditions. Specifically, methods for feeding back into the purification processing conditions include setting the purification process to an endpoint when a certain surface tension is exceeded, or predicting the target surface tension from the change in surface tension to determine the endpoint of the purification process. This enables self-contained processing, optimization of process time, and reduction of manpower in the purification process, thereby improving productivity.

[0087] The purification processing unit 50 may include a purification control unit that provides instructions to feed back the surface tension measured by the surface tension measuring device 100 to the purification processing conditions. The purification control unit can be connected to the load cell 18 and pump 15 of the surface tension measuring device 100 in a communicative manner. The purification control unit may be composed of a CPU, as well as ROM, RAM, and storage. For example, data related to the endpoint of the purification process described above, and a computer program that determines the purification processing conditions based on the fed-back surface tension can be stored in the ROM or storage. Furthermore, the CPU can be configured to load the above computer program into RAM and execute it, thereby enabling the purification processing unit to execute the purification process under appropriate processing conditions. [Examples]

[0088] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited in any way by the following examples unless it exceeds the gist of the invention.

[0089] (Example 1) A surface tension measuring device 100 configured similarly to the surface tension measuring device 100 of the first embodiment described with reference to Figures 1 to 11 was used. The surface tension measuring device 100 of Example 1 is configured such that the measuring probe 19 does not move, and the first container 11, the second container 12, and the cleaning means 17 are installed on a movable stage 10, making them movable. In addition, in the surface tension measuring device 100 of Example 1, water 17a contained in a cleaning container 17b was used as the cleaning means 17 (see Figures 2 and 8). In Example 1, the above-described series of steps were performed by driving the movable stage 10 to move the first container 11, the second container 12, and the cleaning means 17.

[0090] (Example 2) A surface tension measuring device 200 configured similarly to the surface tension measuring device 200 of the second embodiment described with reference to Figure 12 was used. In the surface tension measuring device 200 of Example 2, the first container 11, the second container 12, and the cleaning means 17 do not move, and the load cell 18 is installed on a movable stage 10, so that the load cell 18 and the measuring probe 19 connected to it are movable. In addition, in the surface tension measuring device 200 of Example 2, a small electric furnace 17c capable of heating the measuring probe 19 by electricity was used as the cleaning means 17. In Example 2, the above-described series of steps were performed by driving the movable stage 10 to move the measuring probe 19 connected to the load cell 18.

[0091] (Example 3) A surface tension measuring device 300 configured similarly to the surface tension measuring device 300 of the third embodiment described with reference to Figure 13 was used. In the surface tension measuring device 300 of Example 3, the first container 11, the second container 12, and the cleaning means 17 are installed on a movable stage 10A and are configured to be movable. In addition, in the surface tension measuring device 300 of Example 3, the load cell 18 is installed on the movable stage 10B, so that the load cell 18, the measuring probe 19 connected to the load cell 18, and the vibration suppression mechanism 21 provided on the measuring probe 19 are configured to be movable. In the surface tension measuring device 300 of Example 3, ethanol 17d contained in a cleaning container 17b was used as the cleaning means 17. In Example 3, as in Example 1, a series of steps were performed by driving the movable stage 10A to move the first container 11, the second container 12, and the cleaning means 17.

[0092] (Comparative Example 1) The surface tension measuring device 5 of Comparative Example 1, shown in Figure 15, was used. The surface tension measuring device 5 of Comparative Example 1 differs from the surface tension measuring device 200 of Example 2 (second embodiment), shown in Figure 12, only in that it does not have the vibration suppression mechanism 21 of the surface tension measuring device 200 of Example 2 (second embodiment).

[0093] Specifically, the surface tension measuring device 5 of Comparative Example 1 includes, within its outer cover 1, a first container 11 for containing the first liquid 13, a second container 12 for containing the second liquid 14, a supply passage 16 for the first liquid 13, and a small electric furnace 17c as a cleaning means 17. In the surface tension measuring device 5 of Comparative Example 1, the first container 11, the second container 12, and the cleaning means 17 are arranged on a non-movable stage 20. Furthermore, the surface tension measuring device 5 of Comparative Example 1 includes, within its outer cover 1, a load cell 18, a measuring probe 19 connected to the load cell 18, and a movable stage 10 to which the load cell 18 is fixed. In addition, the surface tension measuring device 5 of Comparative Example 1 includes, outside the outer cover 1, the first liquid 13 and a pump 15 for supplying the first liquid 13. In Comparative Example 1, the corresponding series of steps were performed in the same operation as in Example 2, except that a vibration suppression mechanism was not provided.

[0094] (Measurement of surface tension) The dye aqueous solution was extracted during the purification process and used as the sample (first liquid) for surface tension measurement. In each surface tension measuring device of Examples 1-3 and Comparative Example 1, the surface tension of the extracted dye aqueous solution was measured five times automatically using the same device, and the range of variation in the measured surface tension (unit: mN / m) was confirmed. The range of variation was calculated from the difference between the maximum and minimum values ​​in the five measurements. The results are shown in Table 1.

[0095] TIFF2026102510000002.tif52170

[0096] As shown in Table 1, in the surface tension measuring device of Comparative Example 1, the variation range of the measured surface tension exceeded 2.0 mN / m. In contrast, in the surface tension measuring devices of Examples 1 to 3 (1st to 3rd embodiments), the variation range of the measured surface tension was within 1.0 mN / m, confirming that these surface tension measuring devices can accurately measure the surface tension of the liquid being measured.

[0097] (Example 4) A purification apparatus 400 configured similarly to the purification apparatus 400 of the fourth embodiment described with reference to Figure 14 was used. The purification apparatus 400 of Example 4 is a purification apparatus that adsorbs and removes impurities from an aqueous dye solution using activated carbon. The surface tension measuring device 100 provided in the purification apparatus 400 was the same as the surface tension measuring device 100 of Example 1 (first embodiment). This surface tension measuring device 100 is connected to the purification processing unit 50, and the aqueous dye solution in the purification processing unit 50 is supplied to the first container 11 of the surface tension measuring device 100 through the supply line 16 by the pump 15, and the surface tension is measured by the operation described above. After measuring the surface tension of the aqueous dye solution with the surface tension measuring device 100, the purification apparatus 400 can feed back the measured surface tension value or the measured value of the load cell to the purification processing unit 50 through the signal line 60 to adjust the purification processing conditions.

[0098] (Measurement of surface tension) Using the purification apparatus of Example 4, the surface tension of the dye aqueous solution during the purification process was measured automatically five times, and the range of variation in the measured surface tension (unit: mN / m) was confirmed. The range of variation was calculated from the difference between the maximum and minimum values ​​in the five measurements. The results are shown in Table 2.

[0099] TIFF2026102510000003.tif52170

[0100] As shown in Table 2, in the purification apparatus of Example 4, the range of variation in the measured surface tension was within 1.0 mN / m, confirming that this purification apparatus can accurately measure the surface tension of the measurement solution.

[0101] Furthermore, the disclosure of this embodiment includes the following configurations and methods. (Composition 1) A first container containing the first liquid to be measured, A supply channel for supplying the first liquid into the first container, A surface tension measuring means having a measuring probe connected to a load cell, which measures the surface tension of the first liquid supplied into the first container by a plate method using the measuring probe, A cleaning means for cleaning the measuring probe used for measuring the surface tension, A second container for containing a second liquid used to confirm the cleanliness of the measuring probe after it has been cleaned by the cleaning means, A surface tension measuring device comprising: The surface tension measuring means is also used to measure the surface tension of the second liquid contained in the second container when confirming the cleanliness of the measuring probe. (i) The measuring probe and (ii) at least one of the first container and the second container are configured to be movable within the surface tension measuring device. A surface tension measuring device characterized in that, when the measuring probe is configured to be movable, the measuring probe is equipped with a vibration suppression mechanism. (Configuration 2) The surface tension measuring device according to configuration 1, wherein the vibration suppression mechanism is a mechanism that provides a support body capable of suppressing vibration by contacting the measuring element when the measuring element vibrates, either on the measuring element or at a location between the measuring element and the load cell. (Composition 3) The surface tension measuring device according to configuration 1 or 2, wherein the first liquid is supplied into the first container through the supply channel by a syringe pump. (Composition 4) The surface tension measuring device according to any one of configurations 1 to 3, wherein the cleaning means is a cleaning means that cleans the measuring element using at least one selected from the group consisting of heat, water, and an organic solvent. (Composition 5) A surface tension measuring device according to any one of configurations 1 to 4, wherein the second liquid is water, and the cleanliness is confirmed by measuring the surface tension of the water. (Composition 6) A surface tension measuring device according to any one of configurations 1 to 5, configured to automatically perform a series of operations including supplying the first liquid to the first container, measuring the surface tension of the first liquid, cleaning the measuring probe, and confirming the cleanliness of the measuring probe after cleaning. (Composition 7) A purification apparatus equipped with a surface tension measuring device according to any one of configurations 1 to 6, A purification apparatus characterized in that it is configured to allow the surface tension of the first liquid, measured by the surface tension measuring device, to be fed back into the purification treatment conditions. (Composition 8) The purification apparatus according to configuration 7, wherein the purification apparatus is a purification apparatus for an aqueous dye solution. (Method 1) A step of supplying the first liquid to be measured into the first container, The process involves measuring the surface tension of the first liquid supplied into the first container using a plate method with a surface tension measuring means and a measuring probe connected to a load cell, A step of cleaning the measuring probe used for measuring surface tension, A surface tension measurement method comprising the step of confirming the cleanliness of the measuring probe after washing using a second liquid contained in a second container, The surface tension measuring means is also used to measure the surface tension of the second liquid contained in the second container when confirming the cleanliness of the measuring probe. (i) The measuring probe and (ii) at least one of the first container and the second container are configured to be movable within the surface tension measuring device. A surface tension measurement method characterized in that, when the measuring probe is configured to be movable, the measuring probe is equipped with a vibration suppression mechanism. (Method 2) A purification method using a surface tension measuring device described in any one of items 1 to 6, A purification method characterized by comprising a step of feeding back the surface tension of the first liquid, measured by the surface tension measuring device, to the purification treatment conditions. [Explanation of Symbols]

[0102] 1. Exterior cover 10 movable stages 11 The first container 12 Second container 13 The first liquid 14. The second liquid 15 pumps 16 Supply route 17. Cleaning means 18 Load cell 19 measuring element 20 Non-movable stages 21 Vibration suppression mechanism 50 Purification Processing Section 60 signal line

Claims

1. A first container containing the first liquid to be measured, A supply channel for supplying the first liquid into the first container, A surface tension measuring means having a measuring probe connected to a load cell, which measures the surface tension of the first liquid supplied into the first container by a plate method using the measuring probe, A cleaning means for cleaning the measuring probe used for measuring the surface tension, A second container for containing a second liquid used to confirm the cleanliness of the measuring probe after it has been cleaned by the cleaning means, A surface tension measuring device comprising: The surface tension measuring means is also used to measure the surface tension of the second liquid contained in the second container when confirming the cleanliness of the measuring probe. (i) The measuring probe and (ii) at least one of the first container and the second container are configured to be movable within the surface tension measuring device. A surface tension measuring device characterized in that, when the measuring probe is configured to be movable, the measuring probe is equipped with a vibration suppression mechanism.

2. The surface tension measuring device according to claim 1, wherein the vibration suppression mechanism is a mechanism that provides a support body capable of suppressing vibration by contacting the measuring element when the measuring element vibrates, either on the measuring element or at a location between the measuring element and the load cell.

3. The surface tension measuring device according to claim 1, wherein the first liquid is supplied into the first container through the supply channel by a syringe pump.

4. The surface tension measuring device according to claim 1, wherein the cleaning means is a cleaning means that cleans the measuring element using at least one selected from the group consisting of heat, water, and an organic solvent.

5. The surface tension measuring device according to claim 1, wherein the second liquid is water, and the cleanliness is confirmed by measuring the surface tension of the water.

6. The surface tension measuring device according to claim 1, configured to automatically perform a series of operations: supplying the first liquid to the first container, measuring the surface tension of the first liquid, cleaning the measuring probe, and confirming the cleanliness of the measuring probe after cleaning.

7. A purification apparatus equipped with a surface tension measuring device according to any one of claims 1 to 6, A purification apparatus characterized in that it is configured to allow the surface tension of the first liquid, measured by the surface tension measuring device, to be fed back into the purification treatment conditions.

8. The purification apparatus according to claim 7, wherein the purification apparatus is a purification apparatus for an aqueous dye solution.

9. A step of supplying the first liquid to be measured into the first container, The process involves measuring the surface tension of the first liquid supplied into the first container using a plate method with a measuring probe connected to a load cell, provided by a surface tension measuring means. A step of cleaning the measuring probe used for measuring surface tension, A surface tension measurement method comprising the step of confirming the cleanliness of the measuring probe after washing using a second liquid contained in a second container, The surface tension measuring means is also used to measure the surface tension of the second liquid contained in the second container when confirming the cleanliness of the measuring probe. (i) The measuring probe and (ii) at least one of the first container and the second container are configured to be movable within the surface tension measuring device. A surface tension measurement method characterized in that, when the measuring probe is configured to be movable, the measuring probe is equipped with a vibration suppression mechanism.

10. A purification method using a surface tension measuring device according to any one of claims 1 to 6, A purification method characterized by comprising a step of feeding back the surface tension of the first liquid, measured by the surface tension measuring device, to the purification treatment conditions.

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