Particle size distribution measurement system, particle size distribution measurement method, and particle size distribution measurement program

Abstract

This particle size distribution measurement system comprises: a cell that accommodates a test liquid containing particles; a test liquid supply unit that samples the test liquid from a generation flow passage through which the test liquid flows, and supplies the test liquid to the cell via a flow passage; a particle size distribution measurement unit that measures the particle size distribution of the particles by irradiating the test liquid with light and detecting scattered light produced from the particles; a cleaning liquid supply unit that, after the measurement of the particle size distribution is complete, supplies a cleaning liquid to the cell via a flow passage, said cleaning liquid being a liquid that cleans the cell; and a contamination determination unit that determines contamination of the cell on the basis of transmitted light and / or scattered light from the cell during a condition in which the cleaning liquid is supplied to the cell.

Description

Particle size distribution measurement system, particle size distribution measurement method, and particle size distribution measurement program

[0001] The present invention relates to a particle size distribution measurement system, a particle size distribution measurement method, and a particle size distribution measurement program.

[0002] Conventionally, in order to monitor particle diameters, there has been an online particle diameter distribution measurement system in which a test liquid containing the particles is sampled from a production line where the test liquid is produced, and the particle diameters of the particles contained in the sampled test liquid are measured.

[0003] One such particle size distribution measurement system, as disclosed in Patent Document 1, samples a test liquid from a production line such as factory piping, supplies the sample to a flow cell, and measures the particle size distribution of particles contained in the test liquid while the flow cell contains the test liquid. In the above-described particle size distribution measurement system, a cleaning liquid is supplied to dilute the test liquid to a predetermined ratio as a pretreatment required for measuring the particle size distribution.

[0004] Japanese Patent Application Laid-Open No. 2002-22644

[0005] In the above-described particle size distribution measurement system, the wall surface of the flow cell becomes contaminated due to adhesion of the test liquid to the wall surface of the flow cell. If the wall surface of the flow cell becomes contaminated, there is a risk that the scattered light intensity detected by the detector during particle size distribution measurement will change. Therefore, in order to accurately measure particle size distribution, flow cell maintenance, such as cleaning or replacing the flow cell, is necessary.

[0006] However, because the above particle size distribution measurement system does not detect flow cell contamination, users only become aware of flow cell contamination once it has affected particle size distribution measurements. As a result, after performing flow cell maintenance, users must measure the particle size distribution again in a state where the flow cell is free from contamination, which requires time and effort.

[0007] Conversely, there are cases where flow cell maintenance is performed frequently even when the flow cell is not dirty enough to affect particle size distribution measurement, resulting in increased effort and costs due to cell maintenance. Therefore, with conventional particle size distribution measurement systems, users have been unable to recognize flow cell contamination that would affect particle size distribution measurement at the appropriate time.

[0008] When sampling a test liquid from a production line such as factory piping, as in the above-mentioned particle size distribution measurement system, the increased effort and frequency of cell maintenance may require the production line to be stopped each time, resulting in increased effort and costs due to unnecessary shutdowns of the production line for cell maintenance.

[0009] The present invention has been made in view of the above-mentioned problems, and its main object is to reduce the effort and cost associated with cell maintenance by recognizing, at an appropriate time, cell contamination that affects particle size distribution measurement.

[0010] That is, the particle size distribution measurement system according to the present invention is characterized by comprising: a cell that contains a test liquid that contains particles; a test liquid supply unit that samples the test liquid from a production flow path through which the test liquid flows and supplies the test liquid to the cell via the flow path; a particle size distribution measurement unit that measures the particle size distribution of the particles by irradiating the test liquid with light and detecting scattered light generated from the particles; a cleaning liquid supply unit that supplies a cleaning liquid, which is a liquid for cleaning the cell, to the cell via the flow path after measurement of the particle size distribution is completed; and a contamination determination unit that determines contamination of the cell based on transmitted light and / or scattered light from the cell while the cleaning liquid is being supplied to the cell.

[0011] In such a particle size distribution measurement system, the contamination determination unit determines the contamination of the cell based on at least one of transmitted light and scattered light while cleaning liquid is being supplied to the cell, allowing the user to know whether the cell is contaminated while cleaning liquid is being supplied. Therefore, the user can recognize the timing to perform cell maintenance, such as cleaning or replacing the cell, thereby reducing the effort and cost associated with cell maintenance. Furthermore, in online measurement, in which a test liquid is sampled from a production flow path to measure the particle size distribution of particles contained in the test liquid, the effort and cost of maintaining the cell can be reduced, thereby reducing the effort and cost associated with unnecessary shutdown of the production flow path.

[0012] A specific example of a method for enabling a user to reliably recognize the timing for cell maintenance is one in which the contamination determination unit outputs a maintenance recommendation signal, which is a signal recommending to the user to perform cell maintenance, when the light intensity obtained by detecting the transmitted light and / or the scattered light is below a predetermined value.

[0013] It is preferable that the device further includes a standard particle adding unit that adds standard particles to the flow path while the cleaning liquid is being supplied to the cell, the cleaning liquid supply unit supplies the cleaning liquid and the standard particles to the cell, and the contamination determining unit determines contamination of the cell based on the scattered light while the cleaning liquid and the standard particles are contained in the cell.

[0014] With this configuration, the contamination determining unit determines the contamination of the cell based on the scattered light when the cleaning liquid and the standard particles are contained in the cell, and therefore the intensity of the scattered light is greater when the standard particles are contained in the cell than when the contamination is determined when only the cleaning liquid is contained in the cell, and as a result, the contamination determining unit can accurately determine the presence or absence of contamination in the cell based on the intensity of the scattered light.

[0015] In a particle size distribution measurement system including a pretreatment unit that is provided in the flow path downstream of a cleaning liquid supply unit and that pretreatments the test liquid with a cleaning liquid, if the cleaning liquid supply unit adds standard particles to the flow path upstream of the pretreatment unit, contamination by the standard particles may occur. Therefore, it is preferable that the standard particle addition unit add the standard particles from the flow path downstream of the pretreatment unit.

[0016] The cell has a plurality of wall surfaces, and the particle size distribution measurement system further includes a transmitted light detection unit that detects the transmitted light emitted from the wall surface of the cell, and a scattered light detection unit that detects the scattered light emitted from a wall surface of the cell different from the wall surface from which the transmitted light is emitted, and the contamination determination unit determines contamination on the wall surface of the cell based on the transmitted light intensity obtained from the transmitted light and / or the scattered light intensity obtained from the scattered light.

[0017] With this configuration, the wall surface of the cell where the transmitted light is detected and the wall surface of the cell where the scattered light is detected are different wall surfaces, so the dirt determination unit can determine whether the dirt is present based on the transmitted light intensity and / or the scattered light intensity, thereby identifying which wall surface is dirty, the wall surface where the transmitted light is detected or the wall surface where the scattered light is detected.

[0018] Since the scattered light intensity affects particle size distribution measurement, it is desirable that the contamination determination unit outputs a maintenance recommendation signal, which is a signal recommending maintenance of the cell to the user, at least when the scattered light intensity is below a predetermined value.

[0019] With this configuration, the contamination determination unit outputs a maintenance recommendation signal when the scattered light intensity is below a predetermined value, so that the user can be reliably notified of the need for cell maintenance if the cell has an effect on particle size distribution measurement. Furthermore, for example, if the transmitted light intensity is below a predetermined value but the scattered light intensity is greater than a predetermined value, the user can decide whether or not to output a maintenance recommendation signal, thereby minimizing the effort and cost of cell maintenance.

[0020] Immediately after the cleaning liquid supply unit starts supplying the cleaning liquid to the cell, the test liquid remains in the cell, and the transmitted light intensity and the scattered light intensity change due to the remaining test liquid. Therefore, it is desirable that the contamination determination unit determine the contamination of the cell based on at least one of the transmitted light and the scattered light after a predetermined time has elapsed since the cleaning liquid supply unit started supplying the cleaning liquid to the cell.

[0021] The device may further include a scattering plate insertion mechanism that inserts a scattering plate into the cell when the cleaning liquid is supplied to the cell, and the dirt determination unit may determine the dirt of the cell based on at least one of the transmitted light and the scattered light when the scattering plate is inserted into the cell by the scattering plate insertion mechanism.

[0022] With this configuration, the contamination assessment unit assesses the contamination of the cell with the scattering plate inserted in the cell, and the scattering plate increases the scattered light intensity compared to when the contamination assessment unit assesses contamination with only cleaning liquid contained in the cell, allowing the contamination assessment unit to accurately assess the presence or absence of contamination in the cell based on the scattered light intensity.

[0023] A particle size distribution measurement method used in a particle size distribution measurement system including a cell that contains a test liquid containing particles includes the steps of: sampling the test liquid from a production flow path through which the test liquid flows; supplying the test liquid to the cell via the flow path; measuring the particle size distribution of the particles by irradiating the test liquid with light and detecting scattered light generated from the particles; supplying a cleaning liquid that is a liquid for cleaning the cell to the cell via the flow path after the measurement of the particle size distribution is completed; and determining whether the cell is contaminated based on the transmitted light and / or scattered light from the cell while the cleaning liquid is being supplied to the cell. Furthermore, a particle size distribution measurement program used in a particle size distribution measurement system including a cell that contains a test liquid containing particles, a test liquid supply unit that samples the test liquid from a production flow path through which the test liquid flows and supplies the test liquid to the cell via the flow path, and a cleaning liquid supply unit that supplies a cleaning liquid, which is a liquid for cleaning the cell, to the cell via the flow path after measurement of the particle size distribution of the particles is completed is characterized in that it causes a computer to perform the functions of a particle size distribution measurement unit that measures the particle size distribution of the particles by irradiating the test liquid with light and detecting scattered light generated from the particles, and a contamination determination unit that determines contamination of the cell based on transmitted light and / or scattered light from the cell while the cleaning liquid is being supplied to the cell.

[0024] With this configuration, it is possible to obtain the same effects as those of the particle size distribution measuring system described above.

[0025] According to the present invention configured as described above, by recognizing at an appropriate time any contamination of the cell that affects particle size distribution measurement, it is possible to reduce the effort and cost associated with cell maintenance.

[0026] 1 is a schematic diagram showing a particle size distribution measurement system according to one embodiment of the present invention; FIG. 1 is a schematic diagram showing (a) a cell in a normal state, (b) a cell when maintenance is required, (c) a cell in another case where maintenance is required, and (d) a cell when maintenance is optional in the same embodiment; FIG. 2 is a schematic diagram showing functional blocks of an arithmetic and control device in the same embodiment; FIG. 3 is a flowchart showing a particle size distribution measurement method in the same embodiment; and FIG. 4 is a schematic diagram showing light irradiation to a cell and detection of transmitted light in another embodiment.

[0027] <Present Embodiment> A particle size distribution measurement system 100 according to one embodiment of the present invention will be described below with reference to the drawings. Note that in all of the drawings shown below, some parts may be omitted or exaggerated as appropriate for ease of understanding. Identical components will be assigned the same reference numerals and descriptions thereof will be omitted as appropriate.

[0028] <Particle Size Distribution Measurement System> The particle size distribution measurement system 100 in this embodiment periodically monitors the state of generated particles. Specifically, the particle size distribution measurement system 100 performs online measurement by sampling a test liquid containing particles to be monitored from a production flow path P through which the test liquid flows and measuring the particle size distribution of the particles. Here, the production flow path P is a flow path, such as a factory piping, that is provided in a process for producing the particles to be monitored. In this embodiment, the particle size distribution measurement system 100 measures the particle size distribution by dynamic light scattering, but the particle size distribution may also be measured by laser diffraction scattering, or by other methods.

[0029] In this embodiment, the particle size distribution measurement system 100 monitors particle sizes by carrying out the following steps in order: a sampling step of sampling a test liquid, a measurement step of measuring the particle size distribution of the particles, a cleaning step of cleaning the cell 10, and a standby step of waiting until the start of the next sampling step. Note that the cleaning step here refers to withdrawing the test liquid, whose particle size distribution has been measured in the measurement step, from the cell 10 in order to prevent the test liquid sampled in the next sampling step from being mixed with the test liquid sampled in the previous sampling step.

[0030] 1 , the particle size distribution measurement system 100 includes a cell 10 that contains a test liquid containing particles, a test liquid supply unit 20 that samples the test liquid and supplies the test liquid to the cell 10, a cleaning liquid supply unit 30 that supplies a cleaning liquid for cleaning the cell 10 to the cell 10, a pretreatment unit 40 that is provided in a flow path L downstream of the cleaning liquid supply unit 30, a standard particle addition unit 50 that adds standard particles to the flow path L, a light irradiation unit 60 that irradiates the cell 10 with light, a transmitted light detection unit 70 that detects transmitted light from the cell 10, a scattered light detection unit 80 that detects scattered light from the cell 10, an arithmetic and control device 90 that controls and performs calculations on various devices that constitute the particle size distribution measurement system 100, and a display unit D, such as a display, that displays various data. In this embodiment, the test liquid, cleaning liquid, and standard particles are supplied to the cell 10 via a flow path L connected to a production flow path P. The configuration of each unit will be described below.

[0031] The cell 10 is a flow cell type cell that is provided on the flow path L, contains a test liquid containing particles to be monitored, and discharges the test liquid into the flow path L after the measurement process is completed. The cell 10 is hollow and formed of transparent walls having multiple wall surfaces, and in this embodiment, is roughly rectangular shaped. Opening and closing valves (not shown) are provided on the flow path L upstream and downstream of the cell 10. By opening and closing these opening and closing valves, the test liquid is intermittently introduced into and discharged from the cell 10. Note that in the measurement process of this embodiment, the cell 10 contains the test liquid and a cleaning liquid, but the cell 10 does not necessarily contain a cleaning liquid.

[0032] The test liquid supply unit 20 supplies the test liquid from the production flow path P to the cell 10 via the flow path L. Specifically, the test liquid supply unit 20 has a sampling pump 21 that samples the test liquid from the production flow path P, a sampling switching valve 22 that opens and closes to introduce the test liquid from the production flow path P to the flow path L and to stop sampling, and a supply pump 23 that draws out the cleaning liquid and test liquid from the pretreatment unit 40 and supplies them to the cell 10.

[0033] The cleaning liquid supply unit 30 supplies the cleaning liquid to the cell 10 via the flow path L after the measurement process is completed. Specifically, the cleaning liquid supply unit 30 has a cleaning liquid storage unit 31 that stores the cleaning liquid, a cleaning liquid outlet pump 32 that discharges the cleaning liquid from the cleaning liquid storage unit 31, and a cleaning liquid outlet valve 33 that opens and closes to discharge and stop the discharge of the cleaning liquid from the cleaning liquid storage unit 31 to the pretreatment unit 40. The cleaning liquid referred to here may be, for example, water, physiological saline, or an organic solvent such as ethanol.

[0034] The pretreatment unit 40 is provided in the flow path L downstream of the cleaning liquid supply unit 30 and is, for example, a mixer that mixes the cleaning liquid and the test liquid. In this embodiment, the mixer that constitutes the pretreatment unit 40 is, for example, a static mixer, but is not limited to this and may be a tank that mixes the cleaning liquid and the test liquid, a pH adjuster that adjusts the pH of the test liquid, or other device that pretreats the test liquid.

[0035] In this embodiment, for example, when a high-concentration test liquid containing a high concentration of particles to be measured is sampled, the cleaning liquid also functions as a diluting liquid for diluting the high-concentration test liquid. In this case, in the sampling process, after the cleaning liquid outlet valve 33 is opened and the cleaning liquid outlet pump 32 is driven, the cleaning liquid from the cleaning liquid reservoir 31 and the test liquid sampled by the sampling pump 21 are mixed in the pre-treatment unit 40. Then, the mixed cleaning liquid and test liquid are discharged from the pre-treatment unit 40.

[0036] The standard particle adding unit 50 adds standard particles to the flow path L while the cleaning liquid is being supplied to the cell 10. As a result, during the cleaning process, the cell 10 contains the cleaning liquid and the standard particles. Specifically, the standard particle adding unit 50 includes a standard liquid reservoir 51 for storing a standard liquid containing standard particles, a standard liquid outlet pump 52 for discharging the standard liquid from the standard liquid reservoir 51 to the flow path L, and a standard liquid outlet valve 53 for opening and closing the valve to discharge and stop the standard liquid from the standard liquid reservoir 51 to the flow path L. In this embodiment, it is desirable that the concentration of the standard particles in the standard liquid be appropriately adjusted according to the range of scattered light intensity detected by the scattered light detecting unit 80. Examples of standard particles include polyethylene latex (PSL) standard particles. The standard liquid may be the same as the cleaning liquid in the cleaning liquid reservoir 31, or may be a different liquid from the cleaning liquid.

[0037] In this embodiment, the standard particle adding unit 50 adds standard particles to the flow path L downstream of the position where the cleaning liquid supply unit 30 injects the cleaning liquid into the flow path L. More specifically, the standard particle adding unit 50 is connected to the flow path L between the cell 10 and the pre-treatment unit 40, and adds standard particles to the cleaning liquid delivered from the pre-treatment unit 40.

[0038] The light irradiating unit 60 irradiates the cell 10 with light through the lens R1. In this embodiment, the light irradiating unit 60 irradiates the cell 10 with light at least during the measurement step and the cleaning step.

[0039] The transmitted light detection unit 70 detects transmitted light emitted from the wall surface of the cell 10. Specifically, the transmitted light detection unit 70 detects transmitted light, which is light irradiated from the light irradiating unit 60 and transmitted through the cell 10. In this embodiment, as shown in FIG. 2( a), the transmitted light detection unit 70 detects transmitted light emitted from the wall surface opposite the wall surface of the cell 10 irradiated with light by the light irradiating unit 60. Note that in this embodiment, the transmitted light detection unit 70 detects transmitted light at least during the cleaning process, but may also detect transmitted light in other processes. Furthermore, the transmitted light detection unit 70 may detect transmitted light, for example, through a lens.

[0040] The scattered light detection unit 80 detects scattered light emitted from the wall surface of the cell 10. Specifically, the scattered light detection unit 80 detects scattered light from particles and / or standard particles generated by light irradiated from the light irradiation unit 60. Here, the scattered light detection unit 80 detects scattered light emitted from a wall surface different from the wall surface of the cell 10 from which the transmitted light detected by the transmitted light detection unit 70 is emitted. Specifically, as shown in FIG. 2( a), the scattered light detection unit 80 detects scattered light emitted from a wall surface perpendicular to the wall surface of the cell 10 from which the transmitted light detected by the transmitted light detection unit 70 is emitted. In this embodiment, the scattered light detection unit 80 detects scattered light at least during the measurement process and the cleaning process, but may also detect scattered light in other processes. In this embodiment, the scattered light detection unit 80 detects scattered light via lens R2, but may also detect scattered light without via lens R2.

[0041] The arithmetic and control device 90 is a general-purpose or dedicated computer equipped with a CPU, memory, etc. Specifically, the arithmetic and control device 90 functions as a control unit 91 that controls the valves, pumps, and other devices that constitute the particle size distribution measurement system 100, a particle size distribution measurement unit 92 that measures the particle size distribution of particles contained in the test liquid, a light intensity data storage unit 93 that stores the light intensity of transmitted light and / or scattered light, and a contamination determination unit 94 that determines contamination of the cell 10, by the CPU and its peripheral devices working together in accordance with a program stored in a predetermined area of ​​the memory.

[0042] The particle size distribution measuring section 92 measures the particle size distribution of particles contained in the test liquid based on the scattered light intensity, which is the light intensity obtained by the scattered light detecting section 80 during the measurement step.

[0043] The light intensity data storage unit 93 stores the transmitted light intensity obtained from the transmitted light and / or the scattered light intensity obtained from the scattered light. In this embodiment, the transmitted light intensity and scattered light intensity stored in the light intensity data storage unit 93 are the transmitted light intensity and scattered light intensity when the cell 10 contains a standard particle and is irradiated with light when it is clear that the cell 10 is not dirty or damaged.

[0044] The contamination determination unit 94 determines the contamination of the cell 10 based on the transmitted light and scattered light from the cell 10 while the cleaning liquid is being supplied to the cell 10. The contamination of the cell 10 determined by the contamination determination unit 94 here refers to contamination that has accumulated on the wall of the cell 10 for a long period of time, such that the test liquid adhering to the wall of the cell 10 cannot be completely removed even by the cleaning liquid in the cleaning process.

[0045] When the transmitted light intensity obtained by the transmitted light detection unit 70 and / or the scattered light intensity obtained by the scattered light detection unit 80 are equal to or less than a predetermined value, the contamination determination unit 94 determines that the cell 10 is contaminated. Specifically, as shown in FIG. 3 , the contamination determination unit 94 acquires the transmitted light intensity and / or the scattered light intensity stored in the light intensity data storage unit 93. Also as shown in FIG. 3 , the contamination determination unit 94 acquires the transmitted light intensity obtained by the transmitted light detection unit 70 and / or the scattered light intensity obtained by the scattered light detection unit 80 when the cleaning solution and standard particles are contained in the cell 10. Then, when the transmitted light intensity acquired from the light intensity data storage unit 93 is equal to or less than a predetermined value relative to the transmitted light intensity obtained by the transmitted light detection unit 70, the contamination determination unit 94 determines that the wall surface of the cell 10 from which the transmitted light is emitted or the wall surface of the cell 10 onto which the irradiated light is incident is contaminated. Furthermore, if the scattered light intensity obtained from the light intensity data storage unit 93 is less than a predetermined value relative to the scattered light intensity obtained by the scattered light detection unit 80, the dirt determination unit 94 determines that the wall surface of the cell 10 from which the scattered light is emitted or the wall surface of the cell 10 onto which the irradiated light is incident is dirty.

[0046] Here, when the transmitted light intensity and / or scattered light intensity is equal to or lower than a predetermined value, the contamination determination unit 94 outputs a maintenance recommendation signal, which is a signal recommending maintenance of the cell 10 to the user. Specifically, as shown in FIGS. 2B and 2C, when at least the scattered light intensity obtained by the scattered light detection unit 80 is equal to or lower than a predetermined value relative to the scattered light intensity obtained from the light intensity data storage unit 93 (for example, when the scattered light intensity obtained by the scattered light detection unit 80 is 60% of the scattered light intensity obtained from the light intensity data storage unit 93 when it is clear that the cell 10 is not contaminated or scratched), the contamination determination unit 94 outputs the maintenance recommendation signal. Note that in this embodiment, FIG. 2B illustrates a case where there is contamination on the wall surface of the cell 10 onto which the irradiated light is incident. Also, FIG. 2C illustrates a case where there is contamination on the wall surface of the cell 10 from which the scattered light is emitted.

[0047] On the other hand, as shown in FIG. 2( d ), even if the transmitted light intensity obtained by the transmitted light detection unit 70 is equal to or less than a predetermined value relative to the transmitted light intensity obtained from the light intensity data storage unit 93 (for example, the transmitted light intensity obtained by the transmitted light detection unit 70 is 60% of the transmitted light intensity obtained from the light intensity data storage unit 93 when it is clear that the cell 10 is not dirty or damaged), the scattered light intensity obtained by the scattered light detection unit 80 may not be equal to or less than a predetermined value relative to the scattered light intensity obtained from the light intensity data storage unit 93 (for example, the scattered light intensity obtained by the scattered light detection unit 80 is 100% of the scattered light intensity obtained from the light intensity data storage unit 93 when it is clear that the cell 10 is not dirty or damaged). In this case, the user can arbitrarily set whether or not the contamination determination unit 94 outputs a maintenance recommendation signal. Note that in this embodiment, FIG. 2( d ) illustrates a case where contamination is present on the wall surface of the cell 10 from which the transmitted light is emitted.

[0048] Furthermore, in this embodiment, the contamination determination unit 94 determines the contamination of the cell 10 after a predetermined time has elapsed since the cleaning liquid supply unit 30 started supplying the cleaning liquid to the cell 10. The start of the supply of cleaning liquid here refers to a state in which the control unit 91 opens the cleaning liquid outlet valve 33 and starts driving the cleaning liquid outlet pump 32. When the supply of cleaning liquid starts, the control unit 91 outputs a cleaning start signal, which is a signal indicating that the supply of cleaning liquid has started, to the contamination determination unit 94. Then, the contamination determination unit 94 determines the contamination of the cell 10 after a predetermined time has elapsed since receiving the cleaning start signal.

[0049] <Particle Size Distribution Measuring Method> Next, a particle size distribution measuring method using the particle size distribution measuring system 100 of this embodiment will be described with reference to FIG.

[0050] First, the test liquid supply unit 20 samples the test liquid containing particles to be monitored from the production flow path P (S1). Specifically, the control unit 91 opens the sampling switch valve 22 and starts driving the sampling pump 21, thereby sampling the test liquid from the production flow path P to the flow path L.

[0051] Next, the sampled test liquid is pre-treated in the pre-treatment unit 40 (S2). Specifically, when the sampled test liquid is introduced into the pre-treatment unit 40, the control unit 91 opens the cleaning liquid outlet valve 33 and drives the cleaning liquid outlet pump 32. This introduces the cleaning liquid from the cleaning liquid reservoir 31 into the pre-treatment unit 40, and the cleaning liquid and the test liquid are mixed within the pre-treatment unit 40.

[0052] Next, the test liquid and the cleaning liquid after being mixed in the pretreatment unit 40 are supplied to the cell 10 (S3). Specifically, the supply pump 23 draws out the cleaning liquid and the test liquid from the pretreatment unit 40, and the cleaning liquid and the test liquid are supplied to the measurement position where the light irradiation unit 60 irradiates the cell 10 with light.

[0053] When the test liquid and the cleaning liquid reach the measurement position of the cell 10, the particle size distribution measurement unit 92 measures the particle size distribution of the particles (S4).

[0054] When the measurement of the particle size distribution of the particles is completed, the test liquid and the cleaning liquid are discharged from the cell 10, and the cleaning liquid is injected into the flow path L by the cleaning liquid supply unit 30 (S5). Specifically, the valve on the downstream side of the cell 10 is opened, and the test liquid and the cleaning liquid contained in the cell 10 are discharged from the cell 10. Then, the control unit 91 opens the cleaning liquid discharge valve 33 and drives the cleaning liquid discharge pump 32, and the cleaning liquid is injected from the cleaning liquid reservoir 31 into the flow path L. The injected cleaning liquid is supplied to the cell 10 by the supply pump 23.

[0055] After the washing liquid is injected into the flow path L, the standard particles are added to the flow path L (S6). The standard particles and the washing liquid are supplied at least up to the measurement position of the cell 10.

[0056] When the standard particles and cleaning solution are supplied to the measurement position of the cell 10, the contamination determination unit 94 determines whether the cell 10 is contaminated (S7). Specifically, the contamination determination unit 94 determines whether the scattered light intensity obtained by the scattered light detection unit 80 is equal to or lower than a predetermined value (S8). As shown in Figure 2(b) or 2(c), if the scattered light intensity obtained by the scattered light detection unit 80 is equal to or lower than the predetermined value, the contamination determination unit 94 outputs a maintenance recommendation signal (S9).

[0057] On the other hand, if the scattered light intensity obtained by the scattered light detection unit 80 is not equal to or less than the predetermined value, it is determined whether the transmitted light intensity obtained by the transmitted light detection unit 70 is equal to or less than the predetermined value (S10). As shown in FIG. 2(d), if the transmitted light intensity obtained by the transmitted light detection unit 70 is equal to or less than the predetermined value, the contamination determination unit 94 may or may not output a maintenance recommendation signal based on whether or not a maintenance recommendation signal is output, as set by the user (S11). On the other hand, if the transmitted light intensity obtained by the transmitted light detection unit 70 is not equal to or less than the predetermined value, the contamination determination unit 94 does not output a maintenance recommendation signal (S12).

[0058] Effect of the Present Embodiment According to the particle size distribution measurement system 100 of the present embodiment, while a cleaning liquid is being supplied to the cell 10, the contamination determination unit 94 determines whether the cell 10 is contaminated based on at least one of transmitted light and scattered light. As a result, the user can know whether the cell 10 is contaminated while the cleaning liquid is being supplied. Therefore, the user can recognize the timing to perform maintenance on the cell 10, such as cleaning or replacing the cell 10, thereby reducing the effort and cost of maintaining the cell 10. Particularly in the case of online measurement in which a test liquid is sampled from the production flow path P to measure a particle size distribution, as in the particle size distribution measurement system 100 of the present embodiment, the effort and cost of maintaining the cell 10 are reduced, thereby reducing the effort and cost incurred by unnecessary shutdown of the production flow path P.

[0059] Furthermore, the contamination determination unit 94 outputs a maintenance recommendation signal when the transmitted light intensity and / or scattered light intensity is below a predetermined value, so that the user can reliably recognize when it is time to perform maintenance on the cell 10.

[0060] Furthermore, since the standard particle adding unit 50 adds standard particles to the flow path L while the cleaning liquid is being supplied to the cell 10, the contamination determining unit 94 determines contamination of the cell 10 based on scattered light when the cleaning liquid and standard particles are contained in the cell 10. Therefore, compared to determining contamination when only the cleaning liquid is contained in the cell, the presence of standard particles in the cell 10 increases the scattered light intensity, allowing the contamination determining unit 94 to accurately determine contamination of the cell 10 based on the scattered light intensity. In particular, when the cleaning liquid is water, the addition of standard particles increases the scattered light intensity, allowing the contamination determining unit 94 to accurately determine contamination of the cell 10.

[0061] In addition, the standard particle adding unit 50 adds the standard particles to the flow path downstream of the position where the cleaning liquid supply unit 30 injects the cleaning liquid into the flow path, thereby preventing contamination from occurring due to the addition of the standard particles.

[0062] Furthermore, since the wall surface of the cell 10 where the transmitted light is detected and the wall surface of the cell 10 where the scattered light is detected are different wall surfaces, the dirt determination unit 94 determines dirt based on the transmitted light intensity and the scattered light intensity, and it is possible to identify which wall surface is dirty, the wall surface where the transmitted light is detected or the wall surface where the scattered light is detected.

[0063] Furthermore, the contamination determination unit 94 outputs a maintenance recommendation signal at least when the scattered light intensity is below a predetermined value, so that the user can be reliably notified of the need for maintenance of the cell 10 if the scattered light intensity is affected by the contamination determination unit 94. Furthermore, in this embodiment, for example, even if the transmitted light intensity is below a predetermined value, if the scattered light intensity is greater than a predetermined value, the user is free to decide whether or not to output a maintenance recommendation signal. Therefore, the effort and cost required for maintaining the cell 10 can be kept to a minimum.

[0064] Furthermore, the contamination determination unit 94 determines the contamination of the cell 10 after a predetermined time has elapsed since the cleaning liquid supply unit 30 started to supply the cleaning liquid to the cell 10, so that less of the test liquid remains in the cell 10 compared to immediately after the start of the supply of the cleaning liquid. Therefore, the contamination determination unit 94 can accurately determine the contamination of the cell 10 based on the transmitted light intensity and / or the scattered light intensity.

[0065] Other Embodiments The present invention is not limited to the above-described embodiment.

[0066] In the above embodiment, the particle size distribution measurement system 100 is configured to include the standard particle adding unit 50 in order to increase the scattered light intensity when the contamination determining unit 94 determines contamination of the cell 10. However, the present invention is not limited to this. For example, the particle size distribution measurement system 100 may further include a scattering plate insertion mechanism that inserts a scattering plate into the cell 10 while a cleaning liquid is being supplied to the cell 10, and the contamination determining unit 94 may determine contamination of the cell 10 based on at least one of transmitted light and scattered light while the scattering plate is inserted into the cell 10.

[0067] With this configuration, the contamination determining unit 94 determines whether the cell 10 is contaminated with the scattering plate inserted in the cell 10, and therefore the intensity of the scattered light is increased by the scattering plate compared to when the contamination determining unit 94 determines whether the cell 10 is contaminated with only cleaning liquid contained in the cell 10. As a result, the contamination determining unit 94 can accurately determine whether the cell 10 is contaminated or not based on the intensity of the scattered light.

[0068] In the above embodiment, the contamination determination unit 94 determines the contamination of the cell 10, but it may also determine the success or failure of the cleaning process. Specifically, while the cleaning liquid is being supplied to the cell 10, the light irradiation unit 60 irradiates the cell 10 with light, the scattered light detection unit 80 detects scattered light from the cell 10, and the particle size distribution measurement unit 92 measures the particle size distribution during the cleaning process based on the scattered light. The contamination determination unit 94 then determines whether the test liquid remains in the cell 10 by comparing the particle size distribution during the measurement process with the particle size distribution during the cleaning process. If the particle size distribution during the cleaning process is similar to the particle size distribution during the measurement process, the contamination determination unit 94 determines that the test liquid remains in the cell 10 and that the cleaning process is defective. On the other hand, if the particle size distribution during the cleaning process is not similar to the particle size distribution during the measurement process, it determines that the test liquid does not remain in the cell 10 and that the cleaning process is successful.

[0069] In the above embodiment, the contamination determination unit 94 uses both transmitted light intensity and scattered light intensity, but it may determine contamination of the cell 10 using only one of the light intensities. For example, as shown in FIG. 5 , when the contamination determination unit 94 determines contamination of the cell 10 using only transmitted light intensity, multiple transmitted light detection units 70 are disposed facing different wall surfaces of the cell 10. Then, a light irradiation unit 60 irradiates light onto the wall surfaces of the different cells 10, and the multiple transmitted light detection units 70 detect transmitted light from the wall surfaces of the different cells 10. Thereafter, the contamination determination unit 94 determines which wall surface of the cell 10 is contaminated based on the multiple transmitted light intensities obtained by the multiple transmitted light detection units 70.

[0070] With this configuration, the contamination determining unit 94 can determine contamination of the cell 10 without using scattered light, which eliminates the need for a configuration to increase the scattered light intensity, such as adding standard particles or inserting a scattering plate into the cell 10. As a result, the cost of the devices that make up the particle size distribution measuring system 100 can be reduced.

[0071] In the above embodiment, the particle size distribution measurement system 100 is configured to include the standard particle adding unit 50. However, in order for the contamination determining unit 94 to determine contamination of the cell 10, the particle size distribution measurement system 100 may be configured not to include the standard particle adding unit 50.

[0072] In the above embodiment, the standard particle adding unit 50 adds standard particles to the flow path L downstream of the position where the cleaning liquid supply unit 30 injects the cleaning liquid into the flow path L, but this is not limiting. For example, the standard particle adding unit 50 may add standard particles to the flow path L upstream of the position where the cleaning liquid supply unit 30 injects the cleaning liquid into the flow path L.

[0073] In the above embodiment, the cell 10 has a plurality of wall surfaces, but the cell 10 does not have to have a plurality of wall surfaces in order for the contamination determining unit 94 to simply determine whether the cell 10 is contaminated. For example, the cell 10 may have a generally cylindrical shape with a single wall surface.

[0074] In the above embodiment, whether or not the dirt determining unit 94 outputs a maintenance recommendation signal when the intensity of the transmitted light is equal to or less than a predetermined value but the intensity of the scattered light is greater than a predetermined value is left to the discretion of the user, but this is not limiting. For example, the dirt determining unit 94 may be configured to output a maintenance recommendation signal when the intensity of the transmitted light is equal to or less than a predetermined value regardless of the magnitude of the intensity of the scattered light.

[0075] In the above embodiment, the contamination determining unit 94 determines whether the cell 10 is contaminated after a predetermined time has elapsed since the cleaning liquid supply unit 30 started to supply the cleaning liquid to the cell 10. However, this is not limited to this. For example, the contamination determining unit 94 may determine whether the cell 10 is contaminated approximately at the same time as the cleaning liquid supply unit 30 starts to supply the cleaning liquid to the cell 10.

[0076] 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.

[0077] According to the present invention, by recognizing cell contamination that affects particle size distribution measurement at an appropriate time, it is possible to reduce the effort and cost required for cell maintenance.

[0078] REFERENCE SIGNS LIST 100 Particle size distribution measurement system 10 Cell 20 Test liquid supply section 30 Cleaning liquid supply section 40 Mixer 50 Standard particle addition section 60 Light irradiation section 70 Transmitted light detection section 80 Scattered light detection section 90 Arithmetic and control device 92 Particle size distribution measurement section 94 Contamination determination section L Flow path

Claims

1. A particle size distribution measurement system comprising: a cell for containing a test liquid containing particles; a particle size distribution measurement unit for measuring a particle size distribution of the particles by irradiating the test liquid with light and detecting scattered light generated from the particles; a test liquid supply unit for sampling the test liquid from a production flow path through which the test liquid flows and supplying the test liquid to the cell via the flow path; a cleaning liquid supply unit for supplying a cleaning liquid for cleaning the cell to the cell via the flow path after measurement of the particle size distribution is completed; and a contamination determination unit for determining contamination of the cell based on transmitted light and / or scattered light from the cell while the cleaning liquid is being supplied to the cell.

2. A particle size distribution measuring system as described in claim 1, wherein the contamination determination unit outputs a maintenance recommendation signal that recommends maintenance of the cell to a user when the light intensity obtained by detecting the transmitted light and / or the scattered light is below a predetermined value.

3. A particle size distribution measuring system as described in claim 1 or 2, further comprising a standard particle adding unit that adds standard particles to the flow path while the cleaning liquid is being supplied to the cell, the cleaning liquid supply unit supplies the cleaning liquid and the standard particles to the cell, and the contamination determining unit determines contamination of the cell based on the scattered light while the cleaning liquid and the standard particles are contained in the cell.

4. The particle size distribution measuring system according to claim 3, further comprising a pre-treatment unit provided in the flow path downstream of the cleaning liquid supply unit and pre-treating the test liquid using the cleaning liquid, wherein the standard particle adding unit adds the standard particles from the flow path downstream of the pre-treatment unit.

5. A particle size distribution measuring system as described in any one of claims 1 to 4, wherein the cell has a plurality of wall surfaces, the particle size distribution measuring system further comprises a transmitted light detection unit which detects the transmitted light emitted from the wall surface of the cell, and a scattered light detection unit which detects the scattered light emitted from a wall surface of the cell different from the wall surface from which the transmitted light is emitted, and the contamination determination unit determines contamination of the wall surface of the cell based on the transmitted light intensity obtained from the transmitted light and / or the scattered light intensity obtained from the scattered light.

6. A particle size distribution measuring system as described in claim 5, wherein the contamination determination unit outputs a maintenance recommendation signal that recommends maintenance of the cell to a user at least when the scattered light intensity is below a predetermined value.

7. A particle size distribution measuring system as described in any one of claims 1 to 6, wherein the contamination determination unit determines contamination of the cell based on at least one of the transmitted light and the scattered light after a predetermined time has elapsed since the cleaning liquid supply unit started supplying the cleaning liquid to the cell.

8. A particle size distribution measuring system as described in any one of claims 1 to 7, further comprising a scattering plate insertion mechanism that inserts a scattering plate into the cell when the cleaning liquid is supplied to the cell, and the contamination determination unit determines the contamination of the cell based on at least one of the transmitted light and the scattered light when the scattering plate is inserted into the cell by the scattering plate insertion mechanism.

9. A particle size distribution measuring method used in a particle size distribution measuring system having a cell for containing a test liquid containing particles, comprising the steps of: sampling the test liquid from a production flow path through which the test liquid flows, supplying the test liquid to the cell via the flow path, measuring the particle size distribution of the particles by irradiating the test liquid with light and detecting scattered light generated from the particles, supplying a cleaning liquid for cleaning the cell to the cell via the flow path after the measurement of the particle size distribution is completed, and determining whether the cell is dirty based on the transmitted light and / or scattered light from the cell while the cleaning liquid is being supplied to the cell.

10. A particle size distribution measurement program for use in a particle size distribution measurement system comprising a cell for containing a test liquid containing particles, a test liquid supply unit for sampling the test liquid from a production flow path through which the test liquid flows and supplying the test liquid to the cell via the flow path, and a cleaning liquid supply unit for supplying a cleaning liquid for cleaning the cell to the cell via the flow path after measurement of the particle size distribution of the particles is completed, the program causing a computer to perform a function as a particle size distribution measurement unit that measures the particle size distribution of the particles by irradiating the test liquid with light and detecting scattered light generated from the particles, and a function as a contamination determination unit that determines contamination of the cell based on the transmitted light and / or scattered light from the cell while the cleaning liquid is being supplied to the cell.

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