Particle size distribution measuring device, particle analysis unit, program for particle size distribution measuring device, and bubble removal method

Abstract

In order to ensure measurement reproducibility and measurement accuracy, and in order to enable automatic execution of a bubble removal sequence as needed, this particle size distribution measurement device comprises: a circulation channel L in which a dispersion medium circulates; a flow cell 21 provided in the circulation channel L; an image capturing means 23 that captures a particle image being an image of particles in the flow cell 21; and a bubble removal execution unit 33 that acquires air bubble information and that executes a bubble removal sequence for removing air bubbles from the dispersion medium circulating in the circulation channel L if the air bubble information satisfies predetermined conditions, the air bubble information being information pertaining to the air bubbles in the dispersion medium and obtained on the basis of the particle image.

Description

[Technical field]

[0001] The present invention relates to a particle size distribution measuring device, a particle analysis unit, and a program and a bubble removing method used in the particle size distribution measuring device. [Background technology]

[0002] As shown in Patent Document 1, a conventional particle size distribution measuring device includes a circulation flow path in which a dispersion medium containing a particle group to be measured is circulated, and a flow cell provided in the circulation flow path, and irradiates light onto particles in the flow cell, and calculates the particle size distribution based on the light intensity of the diffracted / scattered light generated thereby.

[0003] In such a configuration, if air bubbles are present in the flow cell, a peak due to the air bubbles will appear in the particle size distribution of the object to be measured, resulting in a decrease in measurement accuracy, etc., and therefore, in order to ensure measurement accuracy, it is necessary to remove the air bubbles from the flow cell and the circulation flow path before starting measurement.

[0004] For this reason, in the past, the particle size distribution was displayed on a simple real-time monitor and the user would check it and, for example, if a peak appeared and disappeared around 100 μm, it would be determined that air bubbles had been mixed in and a bubble removal sequence would be executed to remove the air bubbles from the circulation flow path.

[0005] However, in the above-mentioned debubbling method, the user determines whether or not air bubbles have been mixed in, so whether or not bubbles have been removed to a degree sufficient to ensure measurement accuracy depends on the user's level of skill, which may result in a decrease in measurement reproducibility and measurement accuracy. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2006-71329 A Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, the present invention has been made to solve the above problems, and its main objective is to ensure the reproducibility and accuracy of measurements by automatically executing a bubble removal sequence when air bubbles are contained in the dispersion medium. [Means for solving the problem]

[0008] That is, the particle size distribution measuring device according to the present invention irradiates light onto a particle group to be measured that is dispersed in a dispersion medium, and calculates a particle size distribution of the particle group based on a light intensity signal indicating the light intensity of the diffracted / scattered light generated thereby, and is characterized in comprising: a circulation flow path through which the dispersion medium circulates; a flow cell provided in the circulation flow path; an imaging means for capturing a particle image that is an image of the particles in the flow cell; and a bubble removal execution unit that acquires bubble information that is information regarding bubbles in the dispersion medium, which is information obtained based on the particle image, and executes a bubble removal sequence for removing bubbles from the dispersion medium circulating through the circulation flow path when the bubble information satisfies a predetermined condition.

[0009] With a particle size distribution measuring device configured in this manner, if the air bubble information obtained based on the particle image satisfies predetermined conditions, the bubble removal execution unit automatically executes the bubble removal sequence, thereby ensuring measurement reproducibility and measurement accuracy compared to the conventional method in which the user determines the presence of air bubbles.

[0010] Incidentally, when judging the inclusion of air bubbles by displaying the particle size distribution on a simple real-time monitor as described in the Background Art section, air bubbles may not be detected if there are only a few bubbles. Therefore, if the inclusion of air bubbles is found after the start of measurement, it may be necessary to repeat the measurement. Furthermore, when the particles to be measured are around 100 μm in size, there is a problem in that even if the particle size distribution displayed on the real-time monitor is checked, it is not possible to distinguish between the particles to be measured and air bubbles, making it impossible to determine whether air bubbles are mixed in.

[0011] Therefore, in order to be able to detect even small air bubbles regardless of the particle size of the particle to be measured and to reliably execute a bubble removal sequence when bubble removal is necessary, it is preferable to further provide an air bubble discrimination unit that determines whether a particle shown in the particle image is an air bubble based on the particle image, and for the bubble removal execution unit to acquire the number or percentage of particles identified as bubbles by the air bubble discrimination unit as the bubble information, and to execute the bubble removal sequence when the number or percentage exceeds a predetermined threshold value. With this configuration, the difference between the particles captured in the particle image being air bubbles and the particles to be measured is conspicuous, and therefore by identifying air bubbles based on this particle image, it is possible to identify any air bubbles present, regardless of the particle size of the particles to be measured, as long as even a small amount of air bubbles are present. Then, when the number or ratio of particles identified in this way exceeds a predetermined threshold, the bubble removal sequence is executed, so that the bubble removal sequence can be executed reliably when bubble removal is required.

[0012] A specific embodiment of the air bubble determination unit is to calculate the circularity of a particle shown in the particle image, and determine that the particle is an air bubble if the circularity is equal to or greater than a reference value. In this case, since bubbles have a high degree of circularity, whereas particles to be measured are almost never perfectly circular, it is possible to more reliably determine whether or not a particle shown in a particle image is a bubble.

[0013] For example, in view of the fact that the higher the viscosity of the dispersion medium, the lower the circularity of the bubbles, it is preferable that the bubble determination unit obtains a physical property value of the dispersion medium and changes the reference value using the physical property value. In this case, the reference value can be set taking into account the physical properties of the dispersion medium, such as the viscosity, and the like, making it possible to more accurately identify air bubbles.

[0014] Incidentally, some conventional particle size distribution measuring devices are equipped with an autosampler that introduces a group of particles to be measured into a circulation flow path. With such a device, it is possible to introduce a number of prepared measurement targets one after another, so at first glance it may seem that as long as the prepared measurement targets are simply set in the autosampler, the introduction of the measurement targets and the measurement of particle size distribution will be automatically repeated, greatly reducing the effort required for the entire measurement. However, if measurement is started while air bubbles remain in the dispersion medium after the measurement target is introduced, the measurement result may contain voids. In actual measurements, however, it is necessary to check for air bubbles every time the measurement target is introduced, so it is difficult to say that the effort required for the overall measurement has been significantly reduced. Therefore, in a configuration further including an autosampler that introduces the particle group to be measured into the circulation flow path, it is preferable that the bubble removal sequence is executed by the bubble removal execution unit after the measurement target is introduced by the autosampler. With this configuration, not only can the autosampler introduce the object to be measured, but it can also automate the execution of the subsequent bubble removal sequence. Therefore, by setting the prepared object to be measured in the autosampler, the entire series of operations from introduction, bubble removal, and measurement can be automated, making it possible to significantly reduce the effort required for the entire measurement.

[0015] For example, in order to efficiently remove bubbles according to the number or particle size of the bubbles, it is preferable that the bubble removal sequence changes the operation content of the bubble removal sequence according to the bubble information.

[0016] A specific embodiment for changing the operation content of the bubble removal sequence includes a configuration further including an ultrasonic vibration device provided in the circulation flow path and operating when the bubble removal sequence is executed, and the bubble removal execution unit changes the vibration intensity or vibration time of the ultrasonic vibration generated by the ultrasonic vibration device in accordance with the bubble information.

[0017] It is preferable that the apparatus is configured so that a measurement sequence for measuring the particle size distribution is executed after the bubble removal sequence, and further includes a result storage unit that stores the bubble information acquired in the series of operations and the calculated particle size distribution in association with each other. This can improve the traceability of the measurement results.

[0018] Further, a particle analysis unit according to the present invention is used in a particle size distribution measuring device that irradiates light onto a particle group to be measured that is dispersed in a dispersion medium, and calculates a particle size distribution of the particle group based on a light intensity signal indicating the light intensity of diffracted / scattered light generated thereby. The particle size distribution measuring device is configured to acquire bubble information that is information on bubbles in the dispersion medium, and if the bubble information satisfies a predetermined condition, to execute a bubble removal sequence for removing bubbles from the dispersion medium circulating through the circulation flow path. The particle analysis unit is characterized in that the particle analysis unit includes an imaging means that captures a particle image that is an image of particles in a flow cell provided in the circulation flow path through which the dispersion medium circulates, an air bubble discrimination unit that discriminates whether or not particles shown in the particle image are air bubbles based on the particle image, and a counting unit that counts the number or proportion of particles discriminated as bubbles by the air bubble discrimination unit, and outputs the number or proportion of particles counted by the counting unit to the bubble removal execution unit as the air bubble information.

[0019] Further, a program for a particle size distribution measuring apparatus according to the present invention is a program used in a particle size distribution measuring apparatus that irradiates light onto a particle group to be measured that is dispersed in a dispersion medium, and calculates a particle size distribution of the particle group based on a light intensity signal indicating the light intensity of diffracted / scattered light generated thereby, the particle size distribution measuring apparatus comprising: a circulation flow path through which the dispersion medium circulates; a flow cell provided in the circulation flow path; and an imaging means for capturing a particle image that is an image of particles in the flow cell, the program acquiring information obtained based on the particle image, the bubble information being information regarding bubbles in the dispersion medium, and causing a computer to function as a bubble removal executing unit that executes a bubble removal sequence for removing bubbles from the dispersion medium circulating through the circulation flow path when the bubble information satisfies a predetermined condition.

[0020] In addition, the bubble removal method according to the present invention is a bubble removal method used in a particle size distribution measuring device that irradiates light onto a particle group to be measured that is dispersed in a dispersion medium, and calculates the particle size distribution of the particle group based on a light intensity signal indicating the light intensity of the diffracted / scattered light generated thereby, the particle size distribution measuring device comprising: a circulation flow path through which the dispersion medium circulates; a flow cell provided in the circulation flow path; and an imaging means for capturing a particle image that is an image of the particles in the flow cell; and a computer acquires bubble information that is information regarding bubbles in the dispersion medium, which is information obtained based on the particle image, and, when the bubble information satisfies a predetermined condition, executes a bubble removal sequence for removing bubbles from the dispersion medium circulating through the circulation flow path.

[0021] Such a particle analysis unit and program for a particle size distribution measuring device can also achieve the same effects as those of the above-mentioned particle size distribution measuring device. Effect of the Invention

[0022] According to the present invention described above, when bubbles are contained in the dispersion medium, a bubble removal sequence is automatically executed, and this bubble removal sequence can ensure the reproducibility and measurement accuracy of the measurement. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a diagram showing a schematic diagram of an overall configuration of a particle size distribution measuring device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing a schematic configuration of an autosampler according to the embodiment. [Diagram 3] FIG. 2 is a functional block diagram illustrating functions of the information processing apparatus according to the embodiment. [Figure 4] 4 is a flowchart showing the operation of the particle size distribution measuring device of the embodiment. [Diagram 5] FIG. 2 is a diagram illustrating a schematic diagram of particles appearing in a particle image. [Figure 6] FIG. 11 is a functional block diagram illustrating functions of an information processing device according to another embodiment. [Figure 7] FIG. 11 is a functional block diagram illustrating functions of an information processing device according to another embodiment. [Explanation of symbols]

[0024] 100...Particle size distribution measuring device L Circulation flow path AS: Autosampler X...Ultrasonic vibration device P...Circulation pump 11 Static cell 12...Light source 13 Photodetector 14...Arithmetic unit 20 Particle Analysis Unit 21 Image Cell 22...Light source 23 Imaging means 24 Information processing device 31 Air bubble detector 32 Counting section 33....Bubble removal execution section 34 Dispersion medium information receiving section 41...Result storage unit Z Automatic bubble removal judgment mechanism DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0026] As shown in FIG. 1, the particle size distribution measuring device 100 according to this embodiment measures particle size distribution based on the so-called static light scattering theory. Specifically, light is irradiated onto a particle group to be measured that is dispersed in a dispersion medium, and the particle size distribution of the particle group is calculated based on a light intensity signal indicating the light intensity of the diffracted / scattered light thus generated.

[0027] This particle size distribution measuring device includes a circulation flow path L through which a sample liquid, which is prepared by dispersing a group of particles to be measured in a dispersion medium (water or alcohol), circulates, a scattering cell 11 provided in the circulation flow path L, a light source 12 that irradiates light onto the particles in the scattering cell 11, a photodetector 13 that receives diffracted / scattered light generated by the irradiation of the light, and a calculation device 14 that obtains a light intensity signal of the received light and calculates the particle size distribution.

[0028] The scattering cell 11 is a flow cell through which the sample liquid circulates. In addition to this scattering cell 11, the circulation flow path L is provided with a circulation pump P for circulating the sample liquid, and an ultrasonic vibration device X for separating particles when they aggregate.

[0029] The particle size distribution measuring device 100 of this embodiment further includes an autosampler AS that introduces a particle group to be measured into the circulation flow path L, as shown in FIG. The autosampler AS is configured to sequentially input a plurality of types of measurement objects into the circulation flow path L. Specifically, as shown in FIG. 2, the autosampler AS includes a plurality of containers C in which the measurement objects are stored and a sample input section D into which the measurement objects are input from the containers C, and is configured to guide the measurement objects input into the sample input section D to a dispersion bath B that forms a part of the circulation flow path L. More specifically, the container C above the sample input section D is tilted to input the measurement object into the sample input section D, and then the adjacent container C moves above the sample input section D, and this operation is repeated. The autosampler AS may be configured to automatically adjust the concentration of the sample liquid stored in the dispersion bath B using, for example, a water level sensor not shown. The particle size distribution measuring device 100 may also be configured to automatically adjust the concentration of the sample using a water level sensor or the like provided in the dispersion bath B.

[0030] In addition, the particle size distribution measuring device 100 of this embodiment is capable of analyzing various particle characteristics other than particle size distribution, and specifically, further includes a particle analysis unit 20 that measures physical property values ​​that indicate the physical properties of the particles.

[0031] The particle analysis unit 20 of this embodiment is used to determine whether the dispersion medium flowing through at least the circulation flow path L contains air bubbles. The causes of air bubbles being present in the dispersion medium include, for example, foaming caused by a surfactant introduced to prevent aggregation of the particle group to be measured, air remaining in the device, and the use of a highly viscous dispersion medium.

[0032] 1, the particle analysis unit 20 includes an image cell 21 serving as a flow cell provided in the above-mentioned circulation flow path L, a light source 22 such as an LED that emits light to particles in the image cell 21, an imaging means 23 such as a camera that captures a particle image that is an image of the particles in the image cell 21, and an information processing device 24 that analyzes the above-mentioned particle characteristics by, for example, image processing from the particle image obtained by the imaging means 23. Note that the particle image is not limited to a still image and may be a moving image.

[0033] 3, the particle size distribution measuring device 100 of this embodiment has a function as a bubble removal execution unit 33 that, when particle information obtained based on a particle image satisfies a predetermined condition, executes a bubble removal sequence for removing bubbles from the dispersion medium circulating through the circulation flow path L. In this embodiment, this bubble removal execution unit 33 and the above-mentioned imaging means 23 constitute an automatic bubble removal determination mechanism Z for determining the necessity of executing a bubble removal sequence.

[0034] More specifically, in this embodiment, the above-mentioned calculation device 14 is, physically speaking, a general-purpose or dedicated computer equipped with a CPU, memory, input / output interface, etc., and is configured to perform at least the function of the above-mentioned bubble removal execution unit 33 by causing the CPU and peripheral devices to cooperate in accordance with a specified program stored in a specified area of ​​the memory.

[0035] 3, the information processing device 24 is, physically speaking, a general-purpose or dedicated computer equipped with a CPU, memory, an input / output interface, etc., and is configured to function as an air bubble discriminating unit 31, a counting unit 32, etc. by making the CPU and peripheral devices cooperate with each other in accordance with a predetermined program stored in a predetermined area of ​​the memory. Note that, in this embodiment, the air bubble discriminating unit 31, the counting unit 32, etc. also constitute the automatic bubble removal determination mechanism Z described above.

[0036] Hereinafter, the operation of the particle size distribution measuring apparatus 100 of this embodiment will be described with reference to FIGS. 3 and 4, together with an explanation of each part.

[0037] [Sample introduction sequence] First, when a measurement start signal is input to the particle size distribution measuring device 100, the dispersion medium is introduced into the circulation flow path L. Then, when the water level of the dispersion medium stored in the above-mentioned dispersion bath reaches a predetermined level or higher, the above-mentioned autosampler AS operates to automatically introduce the measurement object into the circulation flow path L (S1). Note that the measurement object may be introduced manually, for example, when the particle size distribution measuring device 100 does not include the autosampler AS.

[0038] [Bubble Check Sequence] In this manner, after the dispersion medium and the measurement target are introduced into the circulation flow path L, the particle analysis unit 20 automatically checks whether or not the sample liquid, in which the particle group to be measured is dispersed in the dispersion medium, contains any air bubbles.

[0039] Specifically, in this air bubble confirmation sequence, first, the imaging means 23 captures a particle image, which is an image of a particle in the imaging cell 21, and this particle image is output from the imaging means 23 to the air bubble discriminating section 31 (S2).

[0040] When the air bubble discriminating unit 31 acquires the particle image, it discriminates whether or not the particle shown in the particle image is an air bubble based on the particle image (S3).

[0041] Here, the way particles appear in the particle image differs (hereinafter referred to as image difference) depending on whether they are air bubbles or particles to be measured. For example, air bubbles have a high degree of circularity (often being almost perfectly round), whereas particles to be measured are almost never perfectly round, so the circularity of the particles appearing in the particle image appears as an image difference.

[0042] Therefore, the air bubble discrimination unit 31 is configured to discriminate whether or not a particle shown in a particle image is an air bubble based on the image difference, and here, the circularity of the particle shown in the particle image is used to discriminate whether or not the particle is an air bubble.

[0043] More specifically, the air bubble discrimination unit 31 calculates the circularity of a particle appearing in a particle image, compares the calculated circularity with a predetermined reference value, and determines that the particle is an air bubble if the calculated circularity is equal to or greater than the reference value.

[0044] Incidentally, the higher the viscosity of the dispersion medium, the more the bubbles contained in the dispersion medium stretch in the direction of the flow of the dispersion medium, and therefore the lower the circularity of the bubbles in the particle image. In other words, the circularity of the bubbles is affected by the physical properties of the dispersion medium, such as the viscosity, composition, concentration, and temperature.

[0045] Therefore, in this embodiment, as shown in FIG. 3, the physical property values ​​such as the viscosity of the dispersion medium can be input via an input means such as a mouse, a keyboard, or a touch panel, and the input physical property values ​​are received by the dispersion medium information receiving unit 34.

[0046] The air bubble discriminating unit 31 of this embodiment is configured to acquire the physical property value received by the dispersion medium information receiving unit 34 and change the above-mentioned reference value using the physical property value. Specifically, for example, the reference value can be calculated using a calculation formula or a lookup table with at least one physical property value (e.g., viscosity) as a parameter, and more specifically, for example, the reference value can be changed to a lower value as the viscosity becomes higher.

[0047] Next, the counting unit 32 counts the number of particles that are determined to be air bubbles by the air bubble discriminator 31 (S4). In other words, the counting unit 32 counts the number of particles whose roundness calculated by the air bubble discriminator 31 is equal to or greater than a reference value. The counting unit 32 may count the particles that are determined to be air bubbles by the air bubble discriminator 31 for one particle image, or may count the particles that are determined to be air bubbles by the air bubble discriminator 31 for multiple particle images (a predetermined number of images or a predetermined period of time). The counting unit 32 may also calculate the ratio of particles determined to be air bubbles to the total number of particles determined by the air bubble discriminator 31. The number and / or ratio of particles counted in this manner is output to the bubble removal executing unit 33 as information on air bubbles obtained based on the particle images (hereinafter referred to as air bubble information). The particle size and particle size distribution of the particles determined to be air bubbles by the air bubble discriminator 31 may be included in the air bubble information.

[0048] When the bubble removal execution unit 33 acquires the above-mentioned bubble information, it judges whether the bubble information satisfies a predetermined condition (S5). The predetermined condition is set so that the measurement accuracy of the particle size distribution measuring device 100 can be guaranteed, in other words, the bubble condition is set so as to satisfy the predetermined condition when the measurement accuracy cannot be guaranteed. More specifically, the bubble information is set so as to satisfy the predetermined condition when there is a high probability that a bubble peak will appear in the particle size distribution calculated by the above-mentioned arithmetic device 14.

[0049] Specifically, the bubble removal executing unit 33 judges whether the number of bubbles (bubble information) acquired as the bubble information exceeds a predetermined threshold (satisfies a predetermined condition), and if the number of bubbles exceeds the threshold, executes a bubble removal sequence for removing bubbles from the dispersion medium circulating through the circulation flow path L (S6). When the proportion of bubbles is acquired as the bubble condition, it may be determined whether the proportion exceeds a predetermined threshold. In other words, the bubble removal executing unit 33 may be configured to execute the bubble removal sequence when one or both of the number and proportion of bubbles exceed a predetermined threshold.

[0050] [Bubble removal sequence] When the bubble removal sequence is executed by the bubble removal execution unit 33, the ultrasonic vibration device X described above operates, and bubbles are removed from the sample liquid (dispersion medium) flowing through the circulation flow path L automatically.

[0051] A more specific example of this bubble removal sequence may be a procedure in which the circulation pump P is first operated and the ultrasonic vibration device X is also operated, the ultrasonic vibration device X is stopped when a predetermined first time has elapsed, and then the circulation pump P is stopped when a predetermined second time has elapsed. The first time may be set to be the same length as the second time, or may be set to be shorter or longer than the second time.

[0052] In this embodiment, the above-mentioned bubble removal executing unit 33 is configured to change the operation content of the bubble removal sequence in response to the bubble information, and here, the vibration intensity or vibration time of the ultrasonic vibration generated by the ultrasonic vibration device X is changed in response to the bubble information. When changing the vibration time, the above-mentioned first time (i.e., the time of one ultrasonic vibration) may be changed, or the second time (i.e., the interval time of repeated ultrasonic vibration) may be changed, or both of these times may be changed. Furthermore, the bubble removal executing unit 33 may change the number of repetitions of the operation of the circulation pump P or the operation of the ultrasonic vibration device X in response to the bubble information. In addition, the bubble removal executing unit 33 may be configured to introduce a defoaming agent into the circulation flow path L in response to the bubble information.

[0053] More specifically, the bubble removal execution unit 33 is configured to change the vibration strength and / or vibration time continuously or in stages according to the number and proportion of bubbles obtained as the bubble information; for example, the greater the number or proportion of bubbles, the stronger the vibration strength or the longer the vibration time.

[0054] When the bubble removal sequence in S6 is thus completed, in this embodiment, the process returns to S2 again, and the bubble confirmation sequence up to S5 is repeated.

[0055] [Measurement sequence] On the other hand, if, in S5, one or both of the number and proportion of air bubbles are equal to or lower than a predetermined threshold value, the measurement sequence is automatically started and the particle size distribution is calculated by the above-mentioned calculation device 14 or the like (S7).

[0056] After the particle size distribution of the measurement target is calculated in this manner, the above-mentioned autosampler then introduces another measurement target into the circulation flow path L (i.e., returns to S1), and the above-mentioned series of operations is repeated.

[0057] According to the particle size distribution measuring device 100 configured in this manner, whether or not a particle shown in a particle image is a bubble is determined based on the roundness, so that even a small number of bubbles can be determined regardless of the particle size of the particle to be measured. Moreover, when the number or ratio of determined bubbles exceeds a threshold value, the bubble removal executing unit 33 automatically executes a bubble removal sequence, so that the execution of this bubble removal sequence can ensure the reproducibility and measurement accuracy of the measurement.

[0058] Furthermore, since the air bubble determination unit 31 changes the reference value against which the calculated circularity is compared, for example, by using a physical property value such as the viscosity of the dispersion medium, it is possible to more accurately determine whether or not a particle shown in the particle image is an air bubble.

[0059] Furthermore, since the bubble removal executing unit 33 changes the operation content of the bubble removal sequence in accordance with the bubble information, an efficient bubble removal sequence can be executed in accordance with, for example, the number or proportion of bubbles.

[0060] In addition, since the particle size distribution measuring device 100 is equipped with an autosampler AS, it is possible to fully automate a series of operations from the sample introduction sequence, through the bubble removal confirmation sequence and bubble removal sequence performed as necessary, to the particle size distribution measurement sequence. Moreover, since the introduction of the measurement target and the calculation of the particle size distribution are repeated sequentially, it is possible to automate the measurement of multiple types of measurement targets, and the effort required for measurement can be significantly reduced.

[0061] The present invention is not limited to the above-described embodiment.

[0062] For example, in the above embodiment, the circularity of a particle shown in a particle image is taken as an example of the image difference between an air bubble and a particle to be measured, but an image difference other than circularity may be used. One example of this is an image difference caused by the difference in refractive index between the air bubble and the measurement target. Specifically, as shown in Fig. 5, a particle captured in a particle image can be distinguished into a bright area (bright area S1) in the center and a dark area (dark area S2) on the periphery, and the size, ratio, area, etc. of the bright area S1 and the dark area S2 may be used as the image difference. As another example, when the particle image is a moving image, the air bubbles shown in the particle image rise to the surface over time, so the movement of the particle, such as the moving direction and moving speed, may be used as the image difference. The air bubble discrimination unit 31 may be configured to compare one or more of the various image differences described above with a predetermined reference value to discriminate whether or not a particle shown in the particle image is an air bubble.

[0063] The particle analysis unit 20 may be used to analyze the physical properties of the particle group to be measured, in addition to determining whether or not the dispersion medium contains air bubbles. Specific examples of the physical properties include the particle diameter (area equivalent circle diameter), aspect ratio, measurement magnification, length, width, maximum distance, circumference, major axis, area (actual measurement μm 2 ), area (pixels), circularity, HS circularity, convexity, solidity, flattening, elongation, intensity average, intensity standard deviation, central coordinate position, particle size distribution, and aggregation rate.

[0064] Furthermore, in the above embodiment, the calculation device 14 has the function of the bubble removal execution unit 33, and the information processing device 24 has the functions of the bubble determination unit 31 and the counting unit 32. However, as shown in FIG. 6, the functions of the bubble determination unit 31, the counting unit 32, and the bubble removal execution unit 33 may be performed by a common CPU, for example, the CPU of the calculation device 14 or the CPU of the information processing device 24.

[0065] Moreover, the functions of the bubble discriminating unit 31 and the counting unit 32 of the above embodiment may be provided in a computer other than the particle size distribution measuring device 100 according to the present invention. In this case, the bubble removal executing unit 33 may be configured to acquire bubble information output from the external computer and execute the bubble removal sequence when the acquired bubble information satisfies a predetermined condition. That is, the automatic bubble removal determination mechanism Z in this case does not include the bubble discriminating unit 31 or the counting unit 32, but at least has the functions of the bubble removal executing unit 33.

[0066] The particle size distribution measuring apparatus 100 in the above embodiment is configured to return to S2 after the bubble removal sequence is completed, but the measurement sequence may be automatically executed without returning to S2 after the bubble removal sequence is completed.

[0067] Furthermore, the air bubble discriminating unit 31 may be configured to calculate the diameter of the air bubbles based on the particle image, and in this case, the bubble removal executing unit 33 may be configured to obtain the diameter of the air bubbles as bubble information and change the operation content of the bubble removal sequence accordingly. Specifically, one example of a mode is one in which the vibration intensity or vibration time of the ultrasonic vibration by the ultrasonic vibration device X is increased as the diameter of the air bubbles calculated by the air bubble discriminating unit 31 increases.

[0068] In addition, in a configuration in which a measurement sequence is executed after a bubble removal sequence, the particle size distribution measuring device 100 may further include a function as a result storage unit 41 that associates and stores the bubble information acquired in this series of operations with the measured particle size distribution (see FIG. 7). Note that, although the result storage unit 41 in FIG. 7 is provided in the arithmetic device 14, it may be provided in the information processing device 24, or may be set in a predetermined area of ​​the memory of another device.

[0069] Specifically, the result storage unit 41 may store bubble information, such as the number, ratio, or particle size of bubbles, acquired by the bubble removal executing unit 33 in the bubble checking sequence, in association with the particle size distribution calculated in the measurement sequence corresponding to this bubble checking sequence. Alternatively, the result storage unit 41 may store the number of bubble removal sequences executed before the measurement sequence is started in association with the particle size distribution. With this configuration, the traceability of the measurement results can be improved.

[0070] Furthermore, the bubble removal execution unit 33 in the above embodiment executes the bubble checking sequence before the measurement sequence, but the bubble checking sequence may be executed during the execution of the measurement sequence. In this case, it is possible to check whether or not the dispersion medium contains air bubbles during the measurement of the particle size distribution, and by providing a function as an alarm that notifies the user if the number or proportion of air bubbles exceeds a predetermined value, it is possible to restart the measurement before it is completed, thereby making the measurement more efficient.

[0071] The computer that performs the function of the bubble removal executing unit 33 may be provided in a remote location away from the measurement site of the particle size distribution. In this case, for example, a particle image captured by an imaging means is uploaded to a server or the like, and the computer in the remote location acquires the particle image, and the bubble removal executing unit 33 performs its function based on the particle image.

[0072] In addition, various modifications and combinations of the embodiments may be made as long as they do not go against the spirit of the present invention. [Industrial Applicability]

[0073] According to the present invention, in order to ensure the reproducibility and accuracy of the measurement, the bubble removal sequence can be automatically executed as necessary.

Claims

1. A particle size distribution measuring device that irradiates a particle group to be measured, which is dispersed in a dispersion medium, with light and calculates a particle size distribution of the particle group based on a light intensity signal indicating the light intensity of diffracted / scattered light generated by the irradiation, a circulation flow path through which the dispersion medium circulates; A flow cell provided in the circulation flow path; An imaging means for capturing a particle image which is an image of particles in the flow cell; a bubble removal execution unit that acquires bubble information, which is information regarding bubbles in the dispersion medium, based on the particle image, and executes a bubble removal sequence for removing bubbles from the dispersion medium circulating through the circulation flow path when the bubble information satisfies a predetermined condition; and an air bubble determination unit that determines whether or not a particle shown in the particle image is an air bubble based on the particle image, The bubble removal execution unit acquires, as the bubble information, the number or ratio of particles identified as bubbles by the bubble discrimination unit, and executes the bubble removal sequence when the number or ratio exceeds a predetermined threshold.

2. 2. The particle size distribution measuring device according to claim 1, wherein the air bubble discriminator calculates a circularity of a particle shown in the particle image, and discriminates the particle as an air bubble when the circularity is equal to or greater than a reference value.

3. 3. The particle size distribution measuring device according to claim 2, wherein the bubble determining section acquires a physical property value of the dispersion medium and changes the reference value using the physical property value.

4. 4. The particle size distribution measuring device according to claim 1, further comprising an autosampler that introduces a particle group to be measured into the circulation flow path, and wherein the bubble removal sequence is executed by the bubble removal execution unit after the measurement target is introduced by the autosampler.

5. The particle size distribution measuring device according to claim 1 , wherein the bubble removal sequence changes an operation content of the bubble removal sequence in response to the bubble information.

6. The apparatus further includes an ultrasonic vibration device that is provided in the circulation flow path and operates when the bubble removal sequence is performed, 6. The particle size distribution measuring apparatus according to claim 5, wherein the bubble removal executing unit changes a vibration intensity or a vibration time of the ultrasonic vibration generated by the ultrasonic vibration device in response to the bubble information.

7. A measurement sequence for measuring the particle size distribution is executed after the bubble removal sequence, The particle size distribution measuring device according to claim 1 , further comprising a result storage unit that stores the air bubble information acquired in the series of operations and the calculated particle size distribution in association with each other.

8. A particle analysis unit for use in a particle size distribution measuring device that irradiates a particle group to be measured, the particle group being dispersed in a dispersion medium, with light and calculates a particle size distribution of the particle group based on a light intensity signal indicating the light intensity of the diffracted / scattered light generated thereby, comprising: a bubble removal execution unit that acquires bubble information, which is information about bubbles in the dispersion medium, and executes a bubble removal sequence for removing bubbles from the dispersion medium circulating through a circulation flow path when the bubble information satisfies a predetermined condition, an imaging means for capturing a particle image, which is an image of particles in a flow cell provided in a circulation flow path through which the dispersion medium circulates; an air bubble determination unit that determines whether or not a particle shown in the particle image is an air bubble based on the particle image; a counting unit that counts the number or the ratio of particles that are determined to be bubbles by the bubble determining unit; outputting the number or ratio of particles counted by the counting unit as the bubble information to the bubble removal executing unit; The bubble removal execution unit acquires the number or percentage of particles identified as bubbles by the bubble discrimination unit as the bubble information, and executes the bubble removal sequence when the number or percentage exceeds a predetermined threshold value.

9. A program used in a particle size distribution measuring device that irradiates a particle group to be measured, which is dispersed in a dispersion medium, with light and calculates a particle size distribution of the particle group based on a light intensity signal indicating the light intensity of diffracted / scattered light generated thereby, the particle size distribution measuring device comprising: a circulation flow path through which the dispersion medium circulates; a flow cell provided in the circulation flow path; and an imaging means that captures a particle image that is an image of particles in the flow cell, a function as an air bubble discrimination unit that discriminates whether or not a particle shown in the particle image is an air bubble based on the particle image; acquires bubble information, which is information regarding bubbles in the dispersion medium, based on the particle image, and, when the bubble information satisfies a predetermined condition, causes the computer to function as a bubble removal execution unit that executes a bubble removal sequence for removing bubbles from the dispersion medium circulating through the circulation flow path; the bubble removal execution unit acquires, as the bubble information, the number or ratio of particles identified as bubbles by the bubble discrimination unit, and executes the bubble removal sequence when the number or ratio exceeds a predetermined threshold.

10. A bubble removal method used in a particle size distribution measuring device that irradiates a particle group to be measured, which is dispersed in a dispersion medium, with light and calculates a particle size distribution of the particle group based on a light intensity signal indicating the light intensity of diffracted / scattered light generated thereby, the particle size distribution measuring device comprising: a circulation flow path through which the dispersion medium circulates; a flow cell provided in the circulation flow path; and an imaging means that captures a particle image that is an image of particles in the flow cell; The computer determining whether or not the particle shown in the particle image is an air bubble based on the particle image; A bubble removal method comprising: acquiring the number or proportion of particles identified as bubbles as bubble information, which is information regarding bubbles in the dispersion medium, based on the particle image; and, when the number or proportion exceeds a predetermined threshold, executing a bubble removal sequence for removing bubbles from the dispersion medium circulating through the circulation flow path.

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