Method for measuring fine bubble concentration, and apparatus for measuring fine bubble concentration

Abstract

This invention provides a method for easily measuring the number concentration of fine bubbles in a liquid. [Solution] The fine bubble concentration measurement method comprises a liquid preparation step (#10), an apparatus preparation step (#20), an infiltration step (#30), a mass measurement step (#40), and a concentration determination step (#50). The liquid preparation step (#10) prepares the liquid to be measured, which contains fine bubbles. The apparatus preparation step (#20) prepares an apparatus including powder and a support for the powder. The infiltration step (#30) infiltrates the powder with the liquid. The mass measurement step (#40) measures the infiltration mass, which is the mass of the liquid that has infiltrated the powder. The concentration determination step (#50) determines the number concentration of fine bubbles in the liquid based on the infiltration mass.

Description

[Technical Field]

[0001] This disclosure relates to a method for measuring the concentration of fine bubbles and a fine bubble concentration measuring apparatus. More specifically, this disclosure relates to a method for measuring the number concentration of fine bubbles in a liquid containing fine bubbles and a fine bubble concentration measuring apparatus. [Background technology]

[0002] Liquids containing fine bubbles are used in a variety of fields. For example, in machining processes such as material removal or cold plastic deformation, a processing fluid (coolant) is essential. Liquids containing fine bubbles are sometimes used as this processing fluid.

[0003] A technique using a processing fluid containing fine bubbles is described, for example, in Japanese Patent Publication No. 2007-331088 (Patent Document 1). Patent Document 1 states that by including microbubbles in the processing fluid during removal processing, processing accuracy and processing speed can be improved, and tool wear can be reduced. Thus, in processing, a processing fluid containing fine bubbles is useful in extending tool life and improving processing efficiency. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2007-331088 [Overview of the project] [Problems that the invention aims to solve]

[0005] In machining processes using liquids containing fine bubbles as processing fluids, it is necessary to control the number concentration of fine bubbles in the liquid (processing fluid) in order for the processing fluid to perform well. While it is possible to directly measure the number concentration of fine bubbles in a liquid using specialized precision measuring instruments, introducing such instruments into a machining environment is not practical. Therefore, it is desirable to be able to easily measure the number concentration of fine bubbles in a liquid without using precision measuring instruments.

[0006] The purpose of this disclosure is to provide a fine bubble concentration measurement method and a fine bubble concentration measurement device that can easily measure the number concentration of fine bubbles in a liquid. [Means for solving the problem]

[0007] The fine bubble concentration measurement method according to this disclosure comprises a liquid preparation step, an apparatus preparation step, an infiltration step, a mass measurement step, and a concentration determination step. The liquid preparation step involves preparing a liquid to be measured that contains fine bubbles. The apparatus preparation step involves preparing an apparatus including powder and a support for the powder. The infiltration step involves infiltrating the powder with liquid. The mass measurement step involves measuring the infiltration mass, which is the mass of the liquid that has infiltrated the powder. The concentration determination step involves determining the number concentration of fine bubbles in the liquid based on the infiltration mass.

[0008] The fine bubble concentration measuring device according to this disclosure is a measuring device for measuring the number concentration of fine bubbles in a liquid. The measuring device comprises a container, an instrument, a mass meter, and a calculation device. The container is capable of containing the liquid to be measured. The instrument includes powder and a support for the powder. The instrument is capable of permeating the powder supported by the support with liquid. The mass meter measures the permeation mass, which is the mass of the liquid that has permeated the powder. The calculation device calculates the number concentration of fine bubbles in the liquid to be measured based on the permeation mass. [Effects of the Invention]

[0009] According to the present disclosure, the number concentration of fine bubbles in a liquid can be easily measured.

Brief Description of the Drawings

[0010] [Figure 1] FIG. 1 is a schematic diagram showing an example of a processing apparatus. [Figure 2] FIG. 2 is a flowchart showing the fine bubble concentration measurement method of the first embodiment. [Figure 3] FIG. 3 is a schematic diagram showing a part of a fine bubble concentration measurement apparatus that can be used in the fine bubble concentration measurement method of the first embodiment. [Figure 4] FIG. 4 is a schematic diagram showing an example of the correlation between the permeation mass and the number concentration (FB concentration) of fine bubbles. [Figure 5] FIG. 5 is a schematic diagram showing a modification example 1 of the instrument in the first embodiment. [Figure 6] FIG. 6 is a schematic diagram showing a modification example 2 of the instrument in the first embodiment. [Figure 7] FIG. 7 is a schematic diagram showing a fine bubble concentration measurement apparatus that can be used in the fine bubble concentration measurement method of the second embodiment. [Figure 8] FIG. 8 is a flowchart showing the fine bubble concentration measurement method of the third embodiment. [Figure 9] FIG. 9 is a schematic diagram showing an example of the correlation between the permeation mass difference and the number concentration (FB concentration) of fine bubbles. [Figure 10] FIG. 10 is a schematic diagram showing a fine bubble concentration measurement apparatus that can be used in the fine bubble concentration measurement method of the fifth embodiment.

Modes for Carrying Out the Invention

[0011] To achieve the above objective, the inventors have diligently studied a method for easily measuring the number concentration of fine bubbles in a liquid, rather than directly measuring it using special precision measuring instruments. In this specification, the number concentration of fine bubbles in a liquid may be referred to as "FB concentration." In this specification, a fine bubble means a microbubble with an average diameter of less than 100.00 μm, as defined in JIS B 8741-1:2019. Microbubbles mean microbubbles with an average diameter of 1.00 μm or more and less than 100.00 μm, and ultrafine bubbles mean microbubbles with an average diameter of 0.01 μm or more and less than 1.00 μm. The average diameter of a fine bubble means the median diameter D50.

[0012] As a result of their investigation, the inventors discovered that the penetration rate of the liquid changes depending on the FB concentration. The penetration rate is determined from the change in the mass of the liquid that penetrates the powder by capillary action over time. In short, the penetration rate corresponds to the mass of the liquid that penetrates the powder in a predetermined time. In this specification, the mass of the liquid that penetrates the powder in such a predetermined time may be referred to as the penetration mass.

[0013] The permeation mass corresponds to the permeation rate and shows a negative correlation with the FB concentration. Specifically, as the FB concentration increases, the permeation of the liquid into the powder is inhibited by the fine bubbles, and the permeation mass (permeation rate) decreases. Conversely, as the FB concentration decreases, the permeation of the liquid into the powder is promoted, and the permeation mass (permeation rate) increases. When the FB concentration is zero, that is, when the liquid does not contain fine bubbles, the permeation mass (permeation rate) is at its maximum.

[0014] Therefore, it can be said that the FB concentration can be determined by measuring the osmotic mass. Thus, osmotic mass can serve as an indicator for managing FB concentration. Measuring osmotic mass is simpler than directly measuring FB concentration using specialized precision measuring instruments.

[0015] The fine bubble concentration measurement method and fine bubble concentration measurement apparatus according to the embodiments of this disclosure were completed based on the above findings.

[0016] The fine bubble concentration measurement method according to this embodiment comprises a liquid preparation step, an apparatus preparation step, an infiltration step, a mass measurement step, and a concentration determination step. The liquid preparation step involves preparing a liquid to be measured that contains fine bubbles. The apparatus preparation step involves preparing an apparatus including powder and a support for the powder. The infiltration step involves infiltrating the powder with the liquid. The mass measurement step involves measuring the infiltration mass, which is the mass of the liquid that has infiltrated the powder. The concentration determination step involves determining the number concentration of fine bubbles in the liquid based on the infiltration mass (first configuration).

[0017] In the first configuration of the measurement method, during the penetration step, the liquid to be measured penetrates the powder, and the mass of the liquid penetrating the powder gradually increases. In the mass measurement step, the penetration mass is measured. Specifically, the mass of the liquid that has penetrated the powder is determined at a predetermined time after the liquid has begun to penetrate the powder. Alternatively, the mass of the liquid that has penetrated the powder is determined at a predetermined time after the powder and / or support comes into contact with the liquid. As described above, the penetration mass corresponds to the penetration rate and shows a negative correlation with the number concentration of fine bubbles (FB concentration) in the liquid. Therefore, in the concentration determination step, the FB concentration in the liquid to be measured can be determined based on the penetration mass measured in the mass measurement step. Furthermore, the measurement of the penetration mass does not require the use of special precision measuring instruments. Thus, according to the measurement method of the first configuration, the FB concentration can be easily measured.

[0018] The above fine bubble concentration measurement method preferably further includes a reference data setting step. In the reference data setting step, a permeation step and a mass measurement step are performed on a reference liquid whose number concentration of fine bubbles is known in advance, and the permeation mass corresponding to the reference liquid is obtained as reference data. In this case, in the concentration determination step, the permeation mass corresponding to the liquid to be measured, obtained in the mass measurement step, is compared with the reference data corresponding to the reference liquid obtained in the reference data setting step, and the number concentration of fine bubbles in the liquid to be measured may be determined (second configuration).

[0019] In the second configuration of the measurement method, the concentration determination step involves comparing the osmotic mass corresponding to the liquid to be measured with reference data to determine the FB concentration in the liquid to be measured. Here, as reference data, for example, the osmotic masses corresponding to two or more reference liquids with known and different FB concentrations can be used. In this case, in the reference data, a known FB concentration is assigned to the osmotic mass of each reference liquid. Hereafter, this reference data will also be referred to as individual reference data.

[0020] Furthermore, similar to individual reference data, when using the osmotic masses corresponding to two or more reference liquids with known and distinct FB concentrations, a calibration curve showing the correlation between osmotic mass and FB concentration may be established as reference data from the osmotic mass of each reference liquid and its FB concentration. Hereinafter, this reference data will also be referred to as the first calibration curve data. In the first calibration curve data, the FB concentration is expressed as a negative function of the osmotic mass. The number of reference liquids that form the basis of the first calibration curve data may be two or more, but preferably five or more.

[0021] Alternatively, the osmotic mass corresponding to a single reference liquid with a known FB concentration can be used as reference data. In this case, by focusing on the osmotic mass difference, which is the difference between the osmotic mass of the reference liquid and the osmotic mass of the liquid being measured, a calibration curve showing the correlation between the osmotic mass difference and the FB concentration can be established as reference data from the osmotic mass of the reference liquid and its FB concentration. Hereafter, this reference data will also be referred to as the second calibration curve data. In the second calibration curve data, the FB concentration is expressed as a positive function of the osmotic mass difference.

[0022] In the second configuration of the measurement method, when individual reference data is adopted in the concentration determination step, the permeation mass corresponding to the liquid to be measured is compared with the reference data. If a matching reference data is found as a result of the comparison, the FB concentration (known) assigned to that reference data can be determined as the FB concentration in the liquid to be measured. If no matching reference data is found as a result of the comparison in the concentration determination step, two reference data and their assigned FB concentrations (known) can be selected, and the FB concentration in the liquid to be measured can be determined by interpolation or extrapolation.

[0023] Furthermore, when the first calibration curve data is used in the concentration determination process, the osmotic mass corresponding to the liquid being measured is compared with the first calibration curve data. Through this comparison, the corresponding FB concentration in the first calibration curve data can be determined as the FB concentration in the liquid being measured. Furthermore, when the second calibration curve data is used in the concentration determination process, the osmotic mass difference, that is, the difference between the osmotic mass corresponding to the liquid being measured and the osmotic mass of the reference liquid, is compared with the second calibration curve data. Through this comparison, the corresponding FB concentration in the second calibration curve data can be determined as the FB concentration in the liquid being measured.

[0024] In the fine bubble concentration measurement method according to the second configuration, preferably, the reference liquid includes a lower limit reference liquid having a lower limit number concentration where the number concentration of fine bubbles is at the lower limit of control, and an upper limit reference liquid having an upper limit number concentration where the number concentration of fine bubbles is at the upper limit of control. The reference data includes lower limit reference data corresponding to the lower limit reference liquid and upper limit reference data corresponding to the upper limit reference liquid. In this case, in the concentration determination step, the permeation mass corresponding to the liquid to be measured, obtained in the mass measurement step, may be compared with the lower limit reference data and the upper limit reference data to determine the number concentration of fine bubbles in the liquid to be measured (third configuration).

[0025] In the third configuration of the measurement method, in the concentration determination step, the FB concentration in the liquid to be measured is determined by comparing the osmotic mass corresponding to the liquid to be measured with the lower limit reference data and the upper limit reference data. Here, the lower limit reference data is based on the osmotic mass corresponding to the lower limit reference liquid, and in the lower limit reference data, the lower limit reference liquid is assigned a known lower limit concentration of fine bubbles. On the other hand, the upper limit reference data is based on the osmotic mass corresponding to the upper limit reference liquid, and in the upper limit reference data, the upper limit reference liquid is assigned a known upper limit concentration of fine bubbles. For example, if the liquid to be measured is a processing fluid, the FB concentration of the lower limit reference liquid and the FB concentration of the upper limit reference liquid correspond to the lower limit and upper limit of the FB concentration range that can be suitably used as a processing fluid, respectively.

[0026] In the third configuration of the measurement method, in the concentration determination step, the permeation mass corresponding to the liquid to be measured is compared with the lower limit reference data and the upper limit reference data. If a matching reference data (lower limit reference data or upper limit reference data) is found as a result of the comparison, the FB concentration (lower limit number concentration or upper limit number concentration) assigned to that reference data can be determined as the FB concentration in the liquid to be measured. In the concentration determination step, if no matching reference data (lower limit reference data or upper limit reference data) is found as a result of the comparison, the FB concentration in the liquid to be measured can be determined by interpolation or extrapolation calculation by referring to the lower limit reference data, the upper limit reference data, and the FB concentrations (lower limit number concentration or upper limit number concentration) assigned to them. In this case, the lower limit reference data and the upper limit reference data are the individual reference data described above.

[0027] In the fine bubble concentration measurement method described above, in the penetration step, after a predetermined time has elapsed since the powder and / or support was brought into contact with the liquid, the instrument may be removed from the liquid, and a mass measurement step may be performed on the removed instrument (fourth configuration).

[0028] In the fourth configuration of the measurement method, the mass of the instrument is measured before the penetration process using a scale or similar device, and then the mass of the instrument is measured again using a scale or similar device in the mass measurement process after the penetration process. The difference between these measured values ​​can then be determined as the penetration mass.

[0029] In a fine bubble concentration measurement method relating to any one of the first to third configurations, the mass measurement step may be performed while the penetration step is being carried out (fifth configuration).

[0030] In the fifth configuration of the measurement method, it becomes possible to determine the number concentration of fine bubbles in the liquid being measured in a short amount of time.

[0031] In the fine bubble concentration measurement method described above, it is preferable that the powder is an inorganic powder (sixth configuration). In this case, it is preferable that the inorganic powder is a metal powder (seventh configuration).

[0032] If the powder is an inorganic powder, as in the configurations of the 6th and 7th models, the powder will not dissolve in the liquid as it permeates the powder, and the powder will not leak out of the filtration membrane. Examples of inorganic powders include metal powders, alumina (Al2O3) powders, and silica powders.

[0033] In the fine bubble concentration measurement method described above, the average diameter of the fine bubbles may be 0.05 μm or more and 50.00 μm or less (8th configuration). That is, the fine bubbles may include ultrafine bubbles with an average particle size of 0.05 μm or more and less than 1.00 μm, or microbubbles with an average diameter of 1.00 μm or more and 50.00 μm or less.

[0034] In the fine bubble concentration measurement method described above, preferably, the median diameter D50 of the powder is 0.10 μm or more and 300.00 μm or less (composition 9).

[0035] As in the ninth configuration, if the median diameter D50 of the powder is between 0.10 μm and 300.00 μm, the penetration of the liquid into the powder due to capillary action is moderately suppressed. As a result, the penetration mass is stable, and it becomes possible to clearly distinguish it from liquids that do not contain fine bubbles.

[0036] In the fine bubble concentration measurement method described above, a typical example is the processing fluid used in machining (component 10). In this case, the FB concentration in the processing fluid can be controlled to an appropriate state. Therefore, the processing fluid can perform well during machining, which in turn extends tool life and improves machining efficiency.

[0037] The fine bubble concentration measuring device according to this embodiment is a measuring device for measuring the number concentration of fine bubbles in a liquid. The measuring device comprises a container, an instrument, a mass meter, and a calculation device. The container is capable of containing the liquid to be measured. The instrument includes powder and a support for the powder. The instrument is capable of permeating the powder supported by the support with liquid. The mass meter measures the permeation mass, which is the mass of the liquid that has permeated the powder. The calculation device calculates the number concentration of fine bubbles in the liquid to be measured based on the permeation mass (11th configuration).

[0038] According to the measuring device of the 11th configuration, the permeation mass of the liquid to be measured contained in a container can be measured using an instrument and a mass meter. That is, it is possible to determine the mass of the liquid that has permeated the powder at a predetermined time after the liquid has begun to permeate the powder. As described above, the permeation mass shows a negative correlation with the number concentration of fine bubbles (FB concentration) in the liquid, so the FB concentration in the liquid to be measured can be determined based on the permeation mass. Also, as described above, the difference in permeation mass shows a positive correlation with the FB concentration, so the FB concentration in the liquid to be measured can be determined based on that difference in permeation mass. Furthermore, the measurement of permeation mass does not require special precision measuring instruments. Therefore, the FB concentration can be measured easily.

[0039] The fine bubble concentration measuring device according to the 11th configuration may further include a memory device. The memory device stores data showing the correlation between the osmotic mass and the number concentration of fine bubbles. The calculation device determines the number concentration of fine bubbles in the liquid to be measured based on the osmotic mass and the data stored in the memory device (12th configuration).

[0040] In the 12th configuration of the measuring device, the osmotic mass of the liquid to be measured, measured by a mass meter, and data showing the correlation between the osmotic mass and the FB concentration, stored in a memory device, can be used by a calculation device to determine the FB concentration in the liquid to be measured.

[0041] The fine bubble concentration measurement method and fine bubble concentration measurement apparatus according to this embodiment will be described below with reference to the drawings. In each figure, the same or equivalent components are denoted by the same reference numerals, and redundant explanations will not be repeated.

[0042] [First Embodiment] The fine bubble concentration measurement method and fine bubble concentration measurement apparatus according to this embodiment are used to measure the number concentration of fine bubbles in a liquid containing fine bubbles. The following explanation will use the case where the liquid to be measured is a processing fluid (coolant) as an example. First, processing using a processing fluid will be described.

[0043] [Regarding processing using a liquid containing fine bubbles as a processing fluid] The processing includes material removal and cold plastic deformation. Material removal processes can be broadly classified into cutting, grinding, and polishing. Cold plastic deformation processes can be broadly classified into wire drawing, cold drawing, cold extrusion, and cold rolling. In these processes, the tool is brought into contact with the workpiece to perform the processing. The processing yields parts such as intermediate or final parts. The material of the workpiece is not particularly limited. For example, if the processing is material removal or cold plastic deformation, the material of the workpiece is metal. In this case, the workpiece is a metallic material, and the part manufactured by the processing is a metallic material. If the processing is material removal, the material of the workpiece may be ceramics, glass, or CFRP (carbon fiber reinforced plastic), etc. The processing is carried out by processing equipment.

[0044] Figure 1 is a schematic diagram showing an example of a processing apparatus. In the example shown in Figure 1, the processing apparatus 1000 is used for material removal. The processing apparatus 1000 comprises a tool 1001, a jig 1002, and a fine bubble generator 1003. Processing with the processing apparatus 1000 uses a processing fluid PF. This processing fluid PF is a liquid containing fine bubbles. The processing apparatus 1000 may also be used for cold plastic deformation.

[0045] Tool 1001 performs machining on the workpiece W. Jig 1002 fixes the workpiece W in place.

[0046] The fine bubble generator 1003 generates fine bubbles in the processing liquid PF. The fine bubble generator 1003 comprises, for example, a processing liquid storage container 1031, a fine bubble generator 1032, a supply pipe 1033, a discharge pipe 1034, and a processing liquid discharge mechanism 1035.

[0047] The processing fluid storage container 1031 is a container capable of storing the processing fluid PF. The processing fluid storage container 1031 is, for example, a tank or a bathtub. The fine bubble generator 1032 generates fine bubbles in the processing fluid PF.

[0048] The supply pipe 1033 is located between the processing fluid storage container 1031 and the fine bubble generator 1032, connecting the processing fluid storage container 1031 and the fine bubble generator 1032. The supply pipe 1033 supplies the processing fluid PF stored in the processing fluid storage container 1031 to the fine bubble generator 1032.

[0049] The discharge pipe 1034 is positioned between the processing fluid storage container 1031 and the fine bubble generator 1032, connecting the processing fluid storage container 1031 and the fine bubble generator 1032. The discharge pipe 1034 discharges the processing fluid PF, which has had fine bubbles generated by the fine bubble generator 1032, from the fine bubble generator 1032 to the processing fluid storage container 1031. As a result, the processing fluid PF containing fine bubbles is stored in the processing fluid storage container 1031.

[0050] The machining fluid PF is a water-soluble machining fluid (coolant). The machining fluid PF may also be a water-insoluble machining fluid. A water-soluble machining fluid is, for example, one selected from the group consisting of emulsion type, soluble type, and solution type. A water-insoluble machining fluid is, for example, a cutting oil.

[0051] Preferably, the processing fluid PF is an emulsion-type water-soluble processing fluid. The emulsion-type water-soluble processing fluid contains, for example, water and a surfactant. The surfactant can be any well-known surfactant. The surfactant is, for example, one or more selected from the group consisting of nonionic surfactants, anionic surfactants, amphoteric surfactants, and cationic surfactants.

[0052] If the processing fluid PF is an emulsion-type water-soluble processing fluid, it may contain other components besides water and surfactants. These other components may include, for example, extreme pressure additives, rust inhibitors, preservatives, friction reducers, etc.

[0053] In the processing fluid PF, the average diameter of the fine bubbles is, for example, between 0.05 μm and 50.00 μm.

[0054] The processing fluid discharge mechanism 1035 comprises a drive source 1351, piping 1352, and a nozzle 1353. One end of piping 1352 is immersed in the processing fluid PF stored in the processing fluid storage container 1031. The other end of piping 1352 is connected to the nozzle 1353. The drive source 1351 supplies the processing fluid PF from the processing fluid storage container 1031 to the nozzle 1353 via piping 1352. The drive source 1351 is, for example, a pump.

[0055] During machining, the nozzle 1353 sprays a machining fluid PF containing fine bubbles and supplies the sprayed machining fluid PF to the workpiece W and the tool 1001. Specifically, the nozzle 1353 flows the machining fluid PF over the part of the tool 1001 that is in contact with the workpiece W, and / or over the part of the workpiece W that is in contact with the tool 1001. In other words, when machining is being performed, the nozzle 1353 flows and supplies the machining fluid PF to the machining point P0.

[0056] The processing apparatus 1000 may further include a processing fluid recovery device 1004. The processing fluid recovery device 1004 includes a recovery pan 1041 and a recovery pipe 1042. The recovery pan 1041 functions as a receptacle for recovering the processing fluid PF discharged from the nozzle 1353 and flowing down to the processing point P0. The recovery pipe 1042 is positioned between the recovery pan 1041 and the processing fluid storage container 1031, connecting the recovery pan 1041 and the processing fluid storage container 1031. The recovery pipe 1042 discharges the processing fluid PF stored in the recovery pan 1041 to the processing fluid storage container 1031. The processing fluid recovery device 1004 allows the processing fluid PF to be circulated and utilized. However, the processing apparatus 1000 does not necessarily have to include the processing fluid recovery device 1004.

[0057] In machining using such a machining apparatus 1000, the tool 1001 is brought into contact with the workpiece W to perform machining and manufacture parts. The parts manufactured are intermediate or final parts. While machining is being performed, a machining fluid PF containing fine bubbles is sprayed from the nozzle 1353 and supplied to the machining point P0. This improves the life of the tool 1001 and improves machining efficiency.

[0058] In processing using a processing fluid PF containing fine bubbles, the number concentration of fine bubbles (FB concentration) in the processing fluid PF is controlled so that the processing fluid PF exhibits good performance. For example, a lower limit number concentration and an upper limit number concentration are set as control standards for the FB concentration of the processing fluid PF. The lower limit number concentration is, for example, 5,000 bubbles / mL, preferably 10,000 bubbles / mL. The upper limit number concentration is, for example, 5,000,000,000 bubbles / mL, preferably 1,000,000,000 bubbles / mL.

[0059] If the FB concentration in the processing fluid PF falls below the lower limit number concentration, for example, the processing speed is reduced and processing continues. In some cases, processing is stopped and the fine bubble generator 1032 is cleaned. On the other hand, if the PB concentration in the processing fluid PF exceeds the upper limit number concentration, new processing fluid PF is added to the processing fluid storage container 1031.

[0060] The following describes a method and apparatus for measuring the fine bubble concentration for controlling the FB concentration in the processing fluid PF.

[0061] [Regarding methods and devices for measuring fine bubble concentration] Referring to Figures 2 and 3, the fine bubble concentration measurement method and fine bubble concentration measurement apparatus of this embodiment will be described. Figure 2 is a flow chart showing the fine bubble concentration measurement method of this embodiment. As shown in Figure 2, the fine bubble concentration measurement method of this embodiment comprises a liquid preparation step (#10), an apparatus preparation step (#20), an infiltration step (#30), a mass measurement step (#40), and a concentration determination step (#50).

[0062] The liquid preparation step (#10) involves preparing the liquid ML (Figure 3) to be measured, which contains fine bubbles. In this embodiment, the liquid ML to be measured is the processing fluid PF used in processing by the processing apparatus 1000. The processing fluid PF stored in the processing fluid storage container 1031 is taken as the liquid ML to be measured.

[0063] Figure 3 is a schematic diagram showing a part of the fine bubble concentration measuring device 100 that can be used in the fine bubble concentration measuring method of this embodiment. Referring to Figure 3, the fine bubble concentration measuring device 100 comprises a container 1 and an instrument 2. Although Figure 3 shows the container 1 and the instrument 2 in a relatively close position, the container 1 and the instrument 2 can be separated.

[0064] Container 1 is, for example, cylindrical with an open top. The container 1 only needs to have an open top; its shape is not particularly limited. The liquid to be measured, ML, i.e., the collected processing liquid PF, is contained in container 1.

[0065] Returning to Figure 2, the apparatus preparation step (#20) involves preparing apparatus 2. Referring again to Figure 3, apparatus 2 includes powder 21 and a support 22 that supports the powder 21. In the example shown in Figure 3, the support 22 is composed of a filtration membrane 221.

[0066] The filtration membrane 221 is impermeable to powder 21 but permeable to liquid ML. In a typical example, the filtration membrane 221 is a nylon mesh. In the example shown in Figure 3, the filtration membrane 221 is sheet-like and encloses the powder 21. The powder 21 enclosed by the filtration membrane 221 is maintained in a conical shape overall. Therefore, the powder 21 is arranged on the filtration membrane 221. That is, the powder 21 is layered on the bottom portion 221a of the filtration membrane 221.

[0067] Returning to Figure 2, the infiltration process (#30) involves bringing the apparatus 2 into contact with the liquid ML and allowing the liquid ML to permeate the powder 21. Specifically, the container 1 is placed below the apparatus 2, and the bottom portion 221a of the filter membrane 221 of the apparatus 2 is brought into contact with the liquid ML in the container 1. When the filter membrane 221 comes into contact with the liquid ML, the liquid ML begins to permeate the powder 21 through the filter membrane 221 due to capillary action. That is, the liquid ML permeates the powder 21 via the filter membrane 221, and the mass of liquid ML permeating the powder 21 gradually increases.

[0068] The mass measurement step (#40) measures the permeation mass me. Specifically, it determines the mass of liquid ML that has permeated the powder 21 at a predetermined time tp elapsed since the liquid ML began to permeate the powder 21. In this embodiment, the total mass of the apparatus 2 and the liquid ML that has permeated the powder 21 is measured at a predetermined time tp elapsed since the apparatus 2, specifically the support 22 (filtration membrane 221) that supports the powder 21, came into contact with the liquid ML. Then, the mass of liquid ML that has permeated the powder 21 is determined from the measured total mass. This mass of liquid ML that has permeated the powder 21 corresponds to the permeation mass me of the liquid ML being measured.

[0069] In this embodiment, the mass measurement step (#40) is performed separately from the penetration step (#30). Specifically, in the penetration step (#30), the instrument 2 is withdrawn from the liquid ML after a predetermined time tp has elapsed since the liquid ML began to penetrate the powder 21. In this embodiment, the instrument 2 is withdrawn from the liquid ML after a predetermined time tp has elapsed since the instrument 2 came into contact with the liquid ML. The predetermined time tp can be constant and is not particularly limited. For example, the predetermined time tp is 61 seconds. Here, the timing at which the liquid ML begins to penetrate the powder 21 can be considered as the timing at which the instrument 2 comes into contact with the liquid ML. The timing at which the instrument 2 comes into contact with the liquid ML can be determined by visual inspection.

[0070] After removing the instrument 2 from the liquid ML, a mass measurement step (#40) is performed on the removed instrument 2. In this case, the mass mt of the instrument 2 containing the powder 21 that has been permeated with liquid ML is measured in the mass measurement step (#40). This mass mt is the total mass of the instrument 2 and the liquid ML that has been permeated with the powder 21. In this embodiment, the mass mt0 of the instrument 2 before the permeation step (#30) is measured in advance, before the liquid ML has been permeated. This mass mt0 is the mass of the instrument 2 before the liquid ML permeates the powder 21. The masses mt and mt0 of the instrument 2 can be measured using a simple mass measuring device such as a balance. The difference between these measured masses mt and mt0 (mt-mt0) is then determined as the permeation mass me.

[0071] The concentration determination step (#50) determines the number concentration of fine bubbles in the liquid ML being measured, based on the osmotic mass me obtained in the mass measurement step (#40). Here, the osmotic mass corresponds to the osmotic rate and shows a negative correlation with the number concentration of fine bubbles in the liquid ML (FB concentration). That is, the FB concentration is expressed as a negative function of the osmotic mass.

[0072] Figure 4 is a schematic diagram showing an example of the correlation between osmotic mass and the number concentration of fine bubbles (FB concentration). In the example shown in Figure 4, the FB concentration is expressed as a negative linear function of the osmotic mass. This function can be used as a calibration curve. This calibration curve corresponds to the first calibration curve data described above. Therefore, in the concentration determination step (#50), the FB concentration in the liquid ML to be measured can be determined based on this calibration curve and the osmotic mass me obtained in the mass measurement step (#40). Furthermore, the measurement of osmotic mass does not require the use of special precision measuring instruments. Therefore, according to this embodiment, the FB concentration can be measured easily.

[0073] In this embodiment, liquid ML is the machining fluid PF used for processing. In this case, the FB concentration in the machining fluid PF can be controlled to an appropriate state. Therefore, the machining fluid PF can perform well during processing, which in turn extends the life of the tool 1001 and improves processing efficiency.

[0074] In the concentration determination step (#50) of this embodiment, as described above, the FB concentration in liquid ML is determined using the permeation mass me, which corresponds to the permeation rate. However, in the concentration determination step (#50) of this embodiment, the permeation mass me may be converted to a permeation rate, and the FB concentration in liquid ML may be determined using this permeation rate. In this case, the permeation rate can be converted by dividing the permeation mass me by a predetermined time tp.

[0075] [Preferred conditions] The following describes preferred conditions in this embodiment.

[0076] The powder 21 only needs to be insoluble in liquid ML. Preferably, the powder 21 is an inorganic powder. If the powder 21 is an inorganic powder, it will not dissolve in the liquid ML during the process of the liquid ML permeating through it, and the powder 21 will not leak out of the filter membrane 221, which is the support 22. Examples of inorganic powders include metal powder, alumina (Al2O3) powder, and silica powder. An example of a metal powder is iron powder. Iron powder is inexpensive, readily available, and highly practical. Preferably, the powder 21 is a metal powder, and more preferably iron powder. However, the powder 21 may be an organic powder, as long as it is insoluble in liquid ML.

[0077] The median diameter D50 of the powder 21 is preferably between 0.10 μm and 300.00 μm. If the median diameter D50 of the powder 21 is too small, the penetration of liquid ML into the powder 21 due to capillary action is excessively suppressed. In this case, the penetration mass me tends to become unstable. On the other hand, if the median diameter D50 of the powder 21 is too large, the penetration of liquid ML into the powder 21 is excessively promoted. In this case, the penetration mass me tends to become equivalent to that of a liquid that does not contain fine bubbles. If the median diameter D50 of the powder 21 is between 0.10 μm and 300.00 μm, the penetration of liquid ML into the powder 21 due to capillary action is moderately suppressed. As a result, the penetration mass me is stable, and it becomes possible to clearly distinguish it from that of a liquid that does not contain fine bubbles. More preferably, the lower limit of the median diameter D50 of the powder 21 is 1.00 μm, and the upper limit is 100.00 μm.

[0078] [Modified version of the first embodiment] Figure 5 is a schematic diagram showing a modified example 1 of the apparatus 2 in this embodiment. Referring to Figure 5, in modified example 1, the apparatus 2 includes powder 21A and a support 22A. The support 22A is composed of a filtration membrane 221A and a tube 222A. The tube 222A has properties that prevent liquid ML from penetrating it. The tube 222A is, for example, cylindrical and has an open upper end. A glass tube can be used as the tube 222A. The filtration membrane 221A is positioned to close the lower end of the tube 222A. The powder 21A is filled inside the tube 222A and layered on top of the filtration membrane 221A.

[0079] In the case of Modification 1, during the penetration step (#30), the filtration membrane 221A of the support 22A comes into contact with the liquid ML. As a result, the liquid ML penetrates into the powder 21A via the filtration membrane 221A.

[0080] Figure 6 is a schematic diagram showing a modified example 2 of the apparatus 2 in this embodiment. Referring to Figure 6, in modified example 2, the apparatus 2 includes powder 21B and a support 22B. The support 22B is composed of a rod 223B. The rod 223B has properties that prevent liquid ML from penetrating it. The material of the rod 223B is, for example, glass. The shape of the rod 223B is, for example, plate-like. The shape of the rod 223B may also be cylindrical, prismatic, or tubular. The powder 21B is laminated on the surface of the rod 223B. The method of laminating the powder 21B is not particularly limited. For example, the powder 21B can be laminated on the surface of the rod 223B by applying powder 21B dissolved in water to the surface of the rod 223B and then drying it.

[0081] In the case of modified example 2, during the penetration process (#30), a portion of the powder 21B laminated on the rod material 223B (support 22B) comes into contact with the liquid ML. As a result, the liquid ML penetrates directly into the powder 21B.

[0082] [Second Embodiment] Figure 7 is a schematic diagram showing a fine bubble concentration measuring device 100A that can be used in the fine bubble concentration measuring method of the second embodiment. The fine bubble concentration measuring device 100A differs from the fine bubble concentration measuring device 100 of the first embodiment in that it includes a mass meter 3 connected to the instrument 2. The mass meter 3 can suspend the instrument 2 and measure the mass of the instrument 2.

[0083] In this embodiment, the mass measurement process (#40) is performed while the penetration process (#30) is carried out. Specifically, in the penetration process (#30), the mass of the device 2, which increases as the liquid ML penetrates the powder 21, that is, the mass of the liquid ML that penetrates the powder 21, is continuously measured by the mass meter 3.

[0084] In this case, during continuous measurement by the mass meter 3, the process moves to the mass measurement step (#40) when a predetermined time tp has elapsed since the liquid ML began to permeate the powder 21, and the permeation mass me is measured. In this embodiment, the process moves to the mass measurement step (#40) when a predetermined time tp has elapsed since the instrument 2 came into contact with the liquid ML, and the permeation mass me is measured. At this time, for example, the mass mt of the instrument 2 containing the powder 21 that the liquid ML has permeated is measured. On the other hand, at the start of the permeation step (#30), the mass mt0 of the instrument 2 in a state where the liquid ML has not yet permeated is measured by the mass meter 3. Therefore, the difference (mt-mt0) between these measured masses mt and mt0 can be obtained as the permeation mass me. However, if the mass mt0 of the instrument 2 in a state where the liquid ML has not yet permeated is reset to zero in the mass meter 3, the mass mt0 of the instrument 2 at the time when a predetermined time tp has elapsed since the instrument 2 came into contact with the liquid ML can be used as the permeation mass me. Here, the timing at which the liquid ML begins to penetrate the powder 21 can be considered as the timing at which the instrument 2 comes into contact with the liquid ML, similar to the first embodiment. However, in this embodiment, if the mass change of the instrument 2 is monitored by the mass meter 3 from the moment the instrument 2 comes into contact with the liquid ML, the timing at which the mass of the instrument 2 begins to increase can be considered as the timing at which the liquid ML begins to penetrate the powder 21. In this case, the timing at which the liquid ML begins to penetrate the powder 21 may be considered as a few seconds after the mass of the instrument 2 begins to increase.

[0085] In this embodiment, the mass measurement step (#40) is performed during the infiltration step (#30). Therefore, compared to the first embodiment in which the mass measurement step (#40) is performed separately from the infiltration step (#30), it is possible to determine the number concentration of fine bubbles in the liquid ML being measured in a shorter time.

[0086] The fine bubble concentration measuring device 100A of this embodiment may also be equipped with a lifting table (not shown). The lifting table is positioned below the container 1 containing the liquid ML to be measured and supports the container 1. At the start of the immersion process (#30), raising the lifting table brings the container 1 and the instrument 2 closer together, allowing the instrument 2 to come into contact with the liquid ML. During the immersion process (#30), gradually lowering the lifting table causes the container 1 and the instrument 2 to gradually move further apart, maintaining the contact state of the instrument 2 with the liquid ML. At the end of the immersion process (#30), lowering the lifting table causes the container 1 and the instrument 2 to move further apart, allowing the instrument 2 to be separated from the container 1.

[0087] [Third Embodiment] Figure 8 is a flowchart showing the fine bubble concentration measurement method of the third embodiment. Referring to Figure 8, the fine bubble concentration measurement method of this embodiment differs from the fine bubble concentration measurement method of the first embodiment mainly in that it includes a reference data setting step (#5).

[0088] As shown in Figure 8, the fine bubble concentration measurement method of this embodiment includes a liquid preparation step (#10), an apparatus preparation step (#20), an infiltration step (#30), a mass measurement step (#40), and a concentration determination step (#50), in addition to a reference data setting step (#5) before each of these steps (#10 to #50). In the reference data setting step (#5), the infiltration step (#30) and the mass measurement step (#40) are performed on two or more reference liquids L1, L2, ... whose number concentrations of fine bubbles are known and different from each other, and the infiltration masses m1, m2, ... corresponding to each of the reference liquids L1, L2, ... are determined as reference data.

[0089] For example, the reference data is the individual reference data described above. Specifically, the reference data uses the osmotic masses m1, m2, ... corresponding to two or more reference liquids L1, L2, ... whose FB concentrations are known. In this case, the FB concentrations of the reference liquids L1, L2, ... are known, and in the reference data, the FB concentration (known) is assigned to the osmotic masses m1, m2, ... of each reference liquid L1, L2, ....

[0090] The known FB concentrations of the reference liquids L1, L2, ... can be obtained using special precision measuring instruments. These instruments include, for example, a laser diffraction particle size distribution analyzer (product name: SALD-7500nano, manufactured by Shimadzu Corporation). In this embodiment, the FB concentrations of the reference liquids L1, L2, ... are not particularly limited and can be arbitrarily selected. One of the reference liquids L1, L2, ... may be a liquid with zero FB concentration, i.e., a liquid that does not contain fine bubbles.

[0091] In the measurement method of this embodiment, the permeation mass me is determined for the liquid ML to be evaluated by following the liquid preparation step (#10), equipment preparation step (#20), permeation step (#30), and mass measurement step (#40) as described above. Then, in the concentration determination step (#50), the permeation mass me is compared with the reference data (permeation mass m1, m2, ...) corresponding to each of the reference liquids L1, L2, ... obtained in the reference data setting step (#5), and the number concentration of fine bubbles in the liquid ML to be measured is determined.

[0092] Specifically, the osmotic mass me corresponding to the liquid ML being measured is compared with reference data (osmotic masses m1, m2, ...). If a matching reference data is found, the FB concentration (known) assigned to that reference data can be determined as the FB concentration in the liquid ML being measured. On the other hand, if no matching reference data is found, two reference data points (osmotic masses m1, m2, ...) are selected, along with the FB concentrations (known) assigned to them. By referring to these selected values, the FB concentration in the liquid ML being measured can be determined by interpolation or extrapolation.

[0093] The reference data may be the first calibration curve data described above. Specifically, similar to the individual reference data, the osmotic masses m1, m2, ... corresponding to two or more reference liquids L1, L2, ... whose FB concentrations are known are used. In this case, the first calibration curve data showing the correlation between osmotic mass and FB concentration is determined as reference data from the osmotic masses m1, m2, ... of each reference liquid L1, L2, ... and their FB concentrations. In the first calibration curve data, the FB concentration is expressed as a negative function of the osmotic mass (Figure 4).

[0094] In this case, the osmotic mass me corresponding to the liquid ML being measured is compared with the first calibration curve data. Through this comparison, the corresponding FB concentration in the first calibration curve data can be determined as the FB concentration in the liquid ML being measured.

[0095] Furthermore, the reference data may be the second calibration curve data described above. Specifically, in the reference data setting step (#5), the permeation step (#30) and the mass measurement step (#40) are performed on one reference liquid Lx whose number concentration of fine bubbles is known in advance, and the permeation mass mx corresponding to the reference liquid Lx is determined as the reference data. That is, the permeation mass mx corresponding to one reference liquid Lx whose FB concentration is known is used. In this case, the permeation mass difference, which is the difference between the permeation mass mx of the reference liquid Lx and the permeation mass me of the liquid ML to be measured, is focused on, and the second calibration curve data showing the correlation between the permeation mass difference and the FB concentration is determined as the reference data from the permeation mass mx of the reference liquid Lx and its FB concentration.

[0096] Figure 9 is a schematic diagram illustrating an example of the correlation between the osmotic mass difference and the number concentration of fine bubbles (FB concentration). In the example shown in Figure 9, the FB concentration is expressed as a positive quadratic function of the osmotic mass difference. In this case, the osmotic mass difference, that is, the difference between the osmotic mass me corresponding to the liquid ML being measured and the osmotic mass mx of the reference liquid Lx, is compared with the second calibration curve data. Through this comparison, the corresponding FB concentration in the second calibration curve data can be determined as the FB concentration in the liquid ML being measured.

[0097] The configuration of this embodiment may also be applied to a second embodiment.

[0098] [Fourth Embodiment] Referring to Figure 8, the fine bubble concentration measurement method of the fourth embodiment will be described. The fine bubble concentration measurement method of this embodiment differs from the fine bubble concentration measurement method of the third embodiment in that the reference data used in the reference data setting step (#5) is limited.

[0099] In the reference data setting step (#5) of this embodiment, the reference liquid includes a lower limit reference liquid LL having a lower limit number concentration where the number concentration of fine bubbles is the lower limit of control, and an upper limit reference liquid LU having an upper limit number concentration where the number concentration of fine bubbles is the upper limit of control. The reference data includes lower limit reference data corresponding to the lower limit reference liquid LL and upper limit reference data corresponding to the upper limit reference liquid LU.

[0100] Specifically, in the reference data setting step (#5), the permeation step (#30) and mass measurement step (#40) are performed on the lower limit reference liquid LL in advance to determine the permeation mass ml corresponding to the lower limit reference liquid LL as the lower limit reference data. Similarly, in the reference data setting step (#5), the permeation step (#30) and mass measurement step (#40) are performed on the upper limit reference liquid LU in advance to determine the permeation mass mu corresponding to the upper limit reference liquid LU as the upper limit reference data.

[0101] The FB concentration of the lower limit reference liquid LL is a known lower limit number concentration, and in the lower limit reference data, the lower limit number concentration is assigned to the permeation mass ml of the lower limit reference liquid LL. On the other hand, the FB concentration of the upper limit reference liquid LU is a known upper limit number concentration, and in the upper limit reference data, the upper limit number concentration is assigned to the permeation mass mu of the upper limit reference liquid LU. The known FB concentrations of the lower limit reference liquid LL and the upper limit reference liquid LU can be obtained using special precision measuring instruments. One example of such a precision measuring instrument is a laser diffraction particle size distribution analyzer (product name: SALD-7500nano, manufactured by Shimadzu Corporation).

[0102] In the measurement method of this embodiment, similar to the third embodiment, the permeation mass me is determined for the liquid ML to be evaluated through a liquid preparation step (#10), an apparatus preparation step (#20), a permeation step (#30), and a mass measurement step (#40). Then, in the concentration determination step (#50), the permeation mass me is compared with the lower limit reference data (permeation mass ml) corresponding to the lower limit reference liquid LL, and the upper limit reference data (permeation mass mu) of the upper limit reference liquid LU, respectively, obtained in the reference data setting step (#5), to determine the number concentration of fine bubbles in the liquid ML to be measured.

[0103] Specifically, the osmotic mass me corresponding to the liquid ML being measured is compared with the lower limit reference data (osmotic mass ml) and the upper limit reference data (osmotic mass mu). If a matching reference data (lower limit reference data or upper limit reference data) is found as a result of the comparison, the FB concentration (lower limit number concentration or upper limit number concentration) assigned to that reference data can be determined as the FB concentration in the liquid ML being measured.

[0104] On the other hand, if no matching reference data (lower limit reference data or upper limit reference data) is found as a result of the comparison, the FB concentration in the liquid ML being measured can be determined by interpolation or extrapolation calculation by referring to the lower limit reference data (osmotic mass ml) and upper limit reference data (osmotic mass mu), as well as the FB concentrations (lower limit number concentration, upper limit number concentration) assigned to them.

[0105] Furthermore, if, as a result of the comparison, no matching reference data (lower limit reference data or upper limit reference data) is found, the osmotic mass me corresponding to the liquid being measured may be determined to be within the control range if it falls between the lower limit reference data (osmotic mass ml) and the upper limit reference data (osmotic mass mu). In other words, if the osmotic mass me is smaller than the lower limit reference data (osmotic mass ml), the FB concentration of the liquid ML may be determined to be greater than the lower limit of control (lower limit number concentration). Moreover, if the osmotic mass me is larger than the upper limit reference data (osmotic mass mu), the FB concentration of the liquid ML may be determined to be less than the upper limit of control (upper limit number concentration). In this specification, such determination is included in determining the FB concentration of the liquid being measured.

[0106] [Fifth Embodiment] Figure 10 is a schematic diagram showing a fine bubble concentration measuring device 100B that can be used in the fine bubble concentration measuring method of the fifth embodiment. The fine bubble concentration measuring device 100B differs from the fine bubble concentration measuring device 100A of the second embodiment in that it further includes a storage device 4 and an arithmetic unit 5.

[0107] Specifically, the storage device 4 and the arithmetic unit 5 are components of the computer. The storage device 4 is memory. The arithmetic unit 5 is a CPU on which programs for performing various processes are installed. The arithmetic unit 5 is connected to the storage device 4. The arithmetic unit 5 is connected to the mass scale 3. The arithmetic unit 5 may also be connected to a display device 6, such as a display monitor, via an interface.

[0108] The storage device 4 stores data showing the correlation between osmotic mass and the number concentration of fine bubbles (FB concentration). This data is, for example, individual reference data showing a negative correlation between osmotic mass and FB concentration, as described above. This individual reference data is, for example, the osmotic masses m1, m2, ... of each reference liquid L1, L2, ... and the FB concentration assigned to them, as described above. This individual reference data may also be, for example, the osmotic mass ml of the lower limit reference liquid LL and the osmotic mass mu of the upper limit reference liquid LU, and the FB concentration (lower limit number concentration, upper limit number concentration) assigned to them, as described above.

[0109] The data stored in the storage device 4 may be the first calibration curve data described above. The data stored in the storage device 4 may also be the second calibration curve data described above.

[0110] In the concentration determination step (#50), the calculation unit 5 acquires the osmotic mass me measured by the mass meter 3, and determines the number concentration of fine bubbles in the liquid ML being measured based on the acquired osmotic mass me and the data stored in the storage device 4. This calculation to determine the FB concentration is performed by a program installed in the calculation unit 5. The determined FB concentration is displayed on the display device 6.

[0111] In the measuring device 100B of this embodiment, the osmotic mass me of the liquid ML to be measured, measured by the mass meter 3, and the data showing the correlation between the osmotic mass and the FB concentration, stored in the storage device 4, can be used by the calculation device 5 to determine the FB concentration in the liquid ML to be measured. [Examples]

[0112] The present disclosure will be further described below with reference to examples. However, the present disclosure is not limited to the following examples.

[0113] A test was conducted to confirm that the penetration rate of a liquid changes depending on the FB concentration. Specifically, the penetration rate coefficient was used as the penetration rate. A dynamic wettability tester (manufactured by Resca Co., Ltd., model: 6200TN) was used as the device for measuring the penetration rate coefficient. Iron powder with a median diameter D50 of 46 μm (manufactured by Kyowa Junyaku Kogyo Co., Ltd.) was used as the powder, and its mass was 5 g. A nylon mesh was used as the filtration membrane constituting the support, and its mesh opening was 20 μm. The mass of the device was set to 0 1 second after the filtration membrane came into contact with the liquid, and the mass of the device was measured until the mass of the liquid penetrating the powder reached saturation. The penetration rate coefficient was determined from the mass measured during the time it took to reach 2 / 3 of saturation. The predetermined time tp was 61 seconds. The penetration rate coefficient was calculated using the known Lucasucas-Washburn equation.

[0114] In Example 1, a processing solution containing 5% by volume of Sugimura Chemical Industry Co., Ltd.'s processing solution concentrate (product name: Sugicut CE14SZ) was prepared as the liquid to be measured. This processing solution was placed in the processing solution storage container shown in Figure 1, and fine bubbles were introduced into the processing solution using a fine bubble generator. Then, a processing solution was prepared after standing for 10 minutes after the introduction of fine bubbles. In addition, a processing solution without the introduction of fine bubbles was prepared. Hereinafter, the processing solution containing fine bubbles, as in the former, will be referred to as "FB processing solution," and the processing solution without fine bubbles, as in the latter, will be referred to as "non-FB processing solution."

[0115] For the FB (fine bubble) processing solution, two types of FB processing solutions were prepared by changing the introduction time of fine bubbles using a fine bubble generator. The FB concentration of the first FB processing solution was 900,000,000 (bubbles / mL). The FB concentration of the second FB processing solution was 1,800,000,000 (bubbles / mL). The FB concentration of the FB-free processing solution was zero.

[0116] In Example 1, the penetration rate coefficient of the FB-free processing liquid (FB concentration: zero) was 3.038 (g 2 / s·10 -2 ). The penetration rate coefficient of the first FB processing liquid (FB concentration: 900,000,000 (per mL)) was 2.605 (g 2 / s·10 -2 ). The penetration rate coefficient of the second FB processing liquid (FB concentration: 1,800,000,000 (per mL)) was 2.115 (g 2 / s·10 -2 ). In the case of such processing liquids, when comparing the FB-free processing liquid with the second FB processing liquid, the penetration rate coefficient changed by 69.6% due to the inclusion of fine bubbles. Also, from these results, it was confirmed that the liquid penetration rate changed according to the FB concentration, and the FB concentration showed a negative correlation with the penetration mass.

Example

[0117] A test was conducted under the same conditions as in Example 1 to confirm that the liquid penetration rate (penetration rate coefficient) changes according to the FB concentration.

[0118] In Example 2, as the liquid to be measured, a processing liquid containing 7% by volume of the processing liquid stock solution (trade name: Daphne Milk Cool AL) manufactured by Idemitsu Kosan Co., Ltd. was prepared. Other conditions were the same as in Example 1. However, the FB concentration of the first FB processing liquid was 400,000,000 (per mL). The FB concentration of the second FB processing liquid was 800,000,000 (per mL).

[0119] In Example 2, the penetration rate coefficient of the FB-free processing liquid (FB concentration: zero) was 4.315 (g 2 / s·10 -2 ). The penetration rate coefficient of the first FB processing liquid (FB concentration: 400,000,000 (per mL)) was 4.205 (g 2 / s·10 -2 ). The penetration rate coefficient of the second FB processing liquid (FB concentration: 800,000,000 (per mL)) was 4.105 (g2 / s·10 -2 ) was the result. In the case of such processing fluids, when comparing a processing fluid without FB with a second FB processing fluid, the penetration rate coefficient changed by 95.1% due to the inclusion of fine bubbles. Furthermore, these results confirmed that the penetration rate of the liquid changes depending on the FB concentration, and that the FB concentration shows a negative correlation with the penetration mass. [Examples]

[0120] Under the same conditions as in Example 1, a test was conducted to confirm that the permeation rate (permeation rate coefficient) of the liquid changes depending on the FB concentration.

[0121] In Example 3, a processing solution containing 5% by volume of Daido Chemical Co., Ltd.'s processing solution concentrate (product name: Similon SCF500) was prepared as the liquid to be measured. Other conditions were the same as in Example 1. However, the FB concentration of the first FB processing solution was 1,200,000,000 (particles / mL). The FB concentration of the second FB processing solution was 2,400,000,000 (particles / mL).

[0122] In Example 3, the penetration rate coefficient of the non-FB processing solution (FB concentration: zero) was 3.812 (g 2 / s·10 -2 The first FB processing solution (FB concentration: 1,200,000,000 (particles / mL)) had a penetration rate coefficient of 3.415 (g 2 / s·10 -2 The second FB processing solution (FB concentration: 2,400,000,000 (particles / mL)) had a penetration rate coefficient of 3.001 (g 2 / s·10 -2 ) was the result. In the case of such processing fluids, when comparing a processing fluid without FB with a second FB processing fluid, the penetration rate coefficient changed by 78.7% due to the inclusion of fine bubbles. Furthermore, these results confirmed that the penetration rate of the liquid changes depending on the FB concentration, and that the FB concentration shows a negative correlation with the penetration mass. [Examples]

[0123] Under the same conditions as in Example 1, a test was conducted to confirm that the permeation rate (permeation rate coefficient) of the liquid changes depending on the FB concentration.

[0124] In Example 4, a processing solution containing 5% by volume of Daido Chemical Co., Ltd.'s processing solution concentrate (product name: Similon EX173) was prepared as the liquid to be measured. Other conditions were the same as in Example 1. However, the FB concentration of the first FB processing solution was 1,100,000,000 (particles / mL). The FB concentration of the second FB processing solution was 2,200,000,000 (particles / mL).

[0125] In Example 4, the penetration rate coefficient of the non-FB processing solution (FB concentration: zero) was 3.158 (g 2 / s·10 -2 The first FB processing solution (FB concentration: 1,100,000,000 (particles / mL)) had a penetration rate coefficient of 2.855 (g 2 / s·10 -2 The second FB processing solution (FB concentration: 2,200,000,000 (particles / mL)) had a permeation rate coefficient of 2.604 (g 2 / s·10 -2 ) was the result. In the case of such processing fluids, when comparing a processing fluid without FB with a second FB processing fluid, the penetration rate coefficient changed by 82.5% due to the inclusion of fine bubbles. Furthermore, these results confirmed that the penetration rate of the liquid changes depending on the FB concentration, and that the FB concentration shows a negative correlation with the penetration mass.

[0126] The embodiments of this disclosure have been described above. However, the embodiments described above are merely examples for implementing this disclosure. Therefore, this disclosure is not limited to the embodiments described above, and the embodiments described above can be modified as appropriate without departing from the spirit of the disclosure.

[0127] For example, the liquid to be measured only needs to contain fine bubbles and may be a liquid used in fields other than processing (e.g., ethanol, oleic acid). [Explanation of Symbols]

[0128] 100, 100A, 100B: Fine bubble concentration measuring device 1: Container 2: Equipment 21,21A,21B: Powder 22,22A,22B:Support 3: Mass meter 4:Storage device 5: Arithmetic device

Claims

1. A liquid preparation step involves preparing a liquid to be measured that contains fine bubbles, A device preparation step involves preparing an apparatus that includes a powder and a support for the powder, An impregnation step in which the liquid is permeated into the powder, A mass measurement step is to measure the permeation mass, which is the mass of the liquid that has permeated the powder. The system includes a concentration determination step of determining the number concentration of the fine bubbles in the liquid based on the aforementioned permeation mass. Method for measuring fine bubble concentration.

2. A method for measuring the fine bubble concentration according to claim 1, further, The system includes a reference data setting step in which the permeation step and the mass measurement step are performed on a reference liquid in which the number concentration of fine bubbles is known in advance, and the permeation mass corresponding to the reference liquid is obtained as reference data. In the concentration determination step, the permeation mass corresponding to the liquid to be measured, obtained in the mass measurement step, is compared with the reference data corresponding to the reference liquid, obtained in the reference data setting step, to determine the number concentration of fine bubbles in the liquid to be measured. Method for measuring fine bubble concentration.

3. A method for measuring the fine bubble concentration according to claim 2, The reference liquid includes a lower limit reference liquid having a lower limit number concentration where the number concentration of the fine bubbles is the lower limit of control, and an upper limit reference liquid having an upper limit number concentration where the number concentration of the fine bubbles is the upper limit of control. The aforementioned standard data includes lower limit standard data corresponding to the lower limit standard liquid and upper limit standard data corresponding to the upper limit standard liquid. In the concentration determination step, the permeation mass corresponding to the liquid to be measured, obtained in the mass measurement step, is compared with the lower limit reference data and the upper limit reference data to determine the number concentration of fine bubbles in the liquid to be measured. Method for measuring fine bubble concentration.

4. A method for measuring the fine bubble concentration according to claim 1, In the penetration step, after the powder and / or the support has been in contact with the liquid and the predetermined time has elapsed, the instrument is removed from the liquid. The mass measurement process is performed on the retrieved instrument. Method for measuring fine bubble concentration.

5. A method for measuring the fine bubble concentration according to claim 1, The mass measurement process is carried out while the aforementioned penetration process is performed. Method for measuring fine bubble concentration.

6. A method for measuring the fine bubble concentration according to claim 1, The aforementioned powder is an inorganic powder. Method for measuring fine bubble concentration.

7. A method for measuring the fine bubble concentration according to claim 6, The inorganic powder is a metal powder. Method for measuring fine bubble concentration.

8. A method for measuring the fine bubble concentration according to claim 1, The average diameter of the fine bubbles is between 0.05 μm and 50.00 μm. Method for measuring fine bubble concentration.

9. A method for measuring the fine bubble concentration according to claim 1, The median diameter D50 of the aforementioned powder is 0.10 μm or more and 300.00 μm or less. Method for measuring fine bubble concentration.

10. A method for measuring the concentration of fine bubbles according to any one of claims 1 to 9, The aforementioned liquid is a processing fluid used in processing. Method for measuring fine bubble concentration.

11. A fine bubble concentration measuring device for measuring the number concentration of fine bubbles in a liquid, A container capable of holding the liquid to be measured, An apparatus comprising a powder and a support for the powder, wherein the liquid can be impregnated into the powder supported by the support, A mass measuring instrument for measuring the permeation mass, which is the mass of the liquid that has permeated the powder, The system includes a calculation device that calculates the number concentration of fine bubbles in the liquid to be measured based on the aforementioned osmotic mass. Fine bubble concentration measuring device.

12. A fine bubble concentration measuring device according to claim 11, further, The device includes a storage device that stores data showing the correlation between the permeation mass and the number concentration of fine bubbles. The calculation device calculates the number concentration of fine bubbles in the liquid to be measured based on the osmotic mass and the data stored in the storage device. Fine bubble concentration measuring device.

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