Water quality measurement system and water quality measurement method

Abstract

Provided are a water quality measurement system and a water quality measurement method, which suppress the generation of pollutants from a device structure such as a switching valve and can measure the water quality of treated water of a measurement object with high precision. The water quality measurement system (10) comprises: a first pipe (11) for circulating first treated water; a first branch pipe (11a) branching from the first pipe (11) and having a first valve (V11); a second pipe (12) for circulating second treated water; a second branch pipe (12a) branching from the second pipe (12) and having a second valve (V12); a third pipe (13) connected to the first pipe (11) and the second pipe (12) for circulating the first treated water and the second treated water; and a water quality measurement device (14) for measuring the water quality of the treated water circulating in the third pipe (13).

Description

Technical Field

[0001] The present invention relates to a water quality measurement system and a water quality measurement method for treated water, and in particular to a water quality measurement system and a water quality measurement method for measuring the presence or absence of impurities such as particles and microorganisms in high-purity treated water such as medical water, pure water, and ultrapure water. Background Art

[0002] Ultrapure water used in semiconductor manufacturing processes, such as cleaning precision electronic components such as semiconductor wafers, is required to remove as much dissolved gases as possible that may promote the proliferation of microorganisms, in addition to dissolving electrolytes, particulates, colloids, high molecular weight organic matter, and heat-generating substances.

[0003] Then, in such ultrapure water, impurities, such as the number of particles, in the produced ultrapure water are measured to confirm whether the water quality satisfies the level required for the ultrapure water.

[0004] To measure the number of particles, ultrapure water collected for measurement from a production line is typically piped through a particle measuring device. To reduce particle count errors, a particle measuring device is known that utilizes a specific piping structure, connecting the branch point of the supply pipe to the particle detection unit solely via piping (see, for example, Patent Document 1).

[0005] In addition, there is known a water quality measuring system which, in measuring the water quality of such water, prevents the water retained in the flow path from mixing with the sample by switching the water in multiple pipelines using a valve and performing measurements using the same measuring device, thereby improving the measurement accuracy (for example, see Patent Document 2).

[0006] In this water quality measurement system, a switching valve is installed at the branching portion of the pipe to control the flow of the collected water, ensuring that the water flows through a predetermined piping structure and switching the flow path. This switching valve ensures that the water being measured flows accurately to the water quality measurement system during measurement.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Laid-Open No. 2001-124692

[0010] Patent Document 2: Japanese Patent Application Laid-Open No. 2014-185904 Summary of the Invention

[0011] Problems to be solved by the invention

[0012] However, as in Patent Document 2, water within multiple pipelines is measured, and if a switching valve is provided at a branching portion of the pipeline, the flow path can be altered by switching the valve. However, this switching valve can introduce contaminants such as particulate matter. Furthermore, when the flow path is switched by the switching valve, stagnant water may remain near the switching valve, potentially causing microbial growth and deteriorating water quality. This water may then flow through the water quality measuring device during the subsequent switching operation.

[0013] In addition, when a multi-way valve or the like is used, which is generally used as a switching valve, water may temporarily stop flowing during switching (for example, see Figure 7A and Figure 7B , Figure 7A Indicates that when water flows from the first flow path, Figure 7B Indicates that the flow path is in the process of switching.) Due to the flow fluctuation during this operation, the stability of the measuring device is lost, which may cause the operation of the measuring device to become temporarily unstable.

[0014] This phenomenon, particularly in the case of ultrapure water with very high purity, means the quality of the produced ultrapure water is not accurately reflected, leading to inaccurate evaluations. Furthermore, to eliminate this effect, a long wait is required until the measured value stabilizes, increasing evaluation time.

[0015] Therefore, the object of the present invention is to provide a water quality measuring system and a water quality measuring method, which, in the measurement of water quality such as ultrapure water, can measure the water quality of multiple treated waters by switching the pipelines flowing in the piping, thereby suppressing the generation of pollutants from device structures such as switching valves, and can measure the water quality of the treated water of the measurement object with high precision.

[0016] Means for solving problems

[0017] The water quality measuring system of the present invention is characterized in that it comprises: a first piping for circulating first treated water; a first branch pipe branching from the first piping and having a first valve; a second piping for circulating second treated water; a second branch pipe branching from the second piping and having a second valve; a third piping connected to the first piping and the second piping for circulating the first treated water and the second treated water; and a water quality measuring device for measuring the water quality of the treated water circulating in the third piping, wherein the third piping includes a connection portion with the first piping and the second piping and does not have a valve.

[0018] The water quality measuring method of the present invention is characterized in that it has: a first supply process, supplying first treated water to a first pipe having a first branch pipe with a first valve; a second supply process, supplying second treated water to a second pipe having a second branch pipe with a second valve; a switching process, closing the first valve and opening the second valve or opening the first valve and closing the second valve, so that one of the first treated water or the second treated water flows to a third pipe connected to the first pipe and the second pipe; and a water quality measuring process, measuring the water quality of the first treated water or the second treated water flowing in the third pipe, wherein the third pipe includes a connection part with the first pipe and the second pipe and does not have a valve.

[0019] Effects of the Invention

[0020] According to the water quality measuring system and water quality measuring method of the present invention, in the water quality measurement of the first treated water and the second treated water, when switching the measurement object, no valve such as a flow path switching valve is set on the flow path connected to the water quality measuring system of the treated water, thereby making the device structure simple and able to be carried out without going through the switching valve, so that the treated water supplied to the water quality measuring system will not be interrupted, and the water quality measurement can be carried out stably.

[0021] In addition, as described above, the water quality measuring system and water quality measuring method of the present invention do not generate particles or the like due to the operation of the switching valve because the treated water being measured does not pass through the switching valve of the flow path. In addition, it is not easy to generate accumulated water retained in the piping, and the contamination of the treated water caused by them can be suppressed, so that the water quality can be measured accurately and stably. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1A This is a diagram showing a schematic configuration of a water quality measurement system according to one embodiment of the present invention.

[0023] Figure 1B It means as Figure 1A A diagram showing a schematic configuration of a water quality measurement system according to a modified example.

[0024] Figure 2A It means Figure 1A Diagram of the flow of treated water in the water quality measurement system.

[0025] Figure 2B It means Figure 1A Diagram of the flow of treated water in the water quality measurement system.

[0026] Figure 3 This is a diagram showing a schematic configuration of a water quality measurement system according to another embodiment of the present invention.

[0027] Figure 4 This is a graph showing the measurement results of the number of fine particles in Example 1.

[0028] Figure 5 This is a graph showing the measurement results of the number of fine particles in Example 2.

[0029] Figure 6 This is a graph showing the measurement results of the number of fine particles in Example 3.

[0030] Figure 7A This is a diagram illustrating a problem when switching a flow path using a switching valve.

[0031] Figure 7B This is a diagram illustrating a problem when switching a flow path using a switching valve. DETAILED DESCRIPTION

[0032] Below, refer to Figures 1A to 3 A water quality measuring system and a water quality measuring method according to embodiments of the present invention will be described in detail.

[0033] (First embodiment)

[0034] [Water quality measurement system]

[0035] like Figure 1A As shown, the water quality measuring system 10 of this embodiment includes a first pipe 11 , a first branch pipe 11 a , a second pipe 12 , a second branch pipe 12 a , a third pipe 13 , and a water quality measuring device 14 .

[0036] The first pipe 11 allows the first treated water to flow through it, and a first branch pipe 11a is provided in the first pipe 11, which branches from the middle of the pipe. Figure 1A In FIG. 1 , the branching portion between the first pipe 11 and the first branch pipe 11 a is represented as a branching point C1 .

[0037] At this time, a first valve V11 is provided on the first branch pipe 11a. By opening and closing the first valve V11, the first treated water can be directed to flow directly through the first pipe 11 or to flow through the first branch pipe 11a. Therefore, it is possible to arbitrarily determine whether the first treated water flowing through the first pipe 11 flows directly into the first pipe 11 or into the first branch pipe 11a.

[0038] The first valve V11 basically allows the first treated water to flow through either the first piping 11 or the first branch pipe 11a by opening and closing. However, when a valve that can change the flow rate by adjusting its opening is used as the first valve V11, the amount of first treated water flowing in the first branch pipe 11a can also be adjusted to a desired amount.

[0039] In this case, for example, the first treated water can be directed primarily to the first pipe 11, with a portion directed to the first branch pipe 11a. Directing a portion of the first treated water to flow into the first branch pipe 11a effectively prevents the first treated water from stagnating in the first branch pipe 11a between the branch point C1 and the first valve V11.

[0040] In addition, even when the first valve V11 is set to a completely closed mode, in order to prevent stagnation, a first release pipe (drainage) that allows a small amount of first treated water to flow and be discharged can be set in the first branch pipe 11a. In this way, the stagnation of the first treated water can also be effectively prevented.

[0041] The second pipe 12 allows the second treated water to flow, and a second branch pipe 12a is provided in the second pipe 12, which branches from the middle of the pipe. Figure 1A In FIG. 1 , the branching portion between the second pipe 12 and the second branch pipe 12 a is represented as a branch point C2 .

[0042] At this time, a second valve V12 is provided on the second branch pipe 12a. By opening and closing the second valve V12, the second treated water can be changed to flow directly into the second pipe 12 or to flow into the second branch pipe 12a. Therefore, it is possible to arbitrarily determine whether the second treated water flowing through the second pipe 12 flows directly into the second pipe 12 or into the second branch pipe 12a.

[0043] The second valve V12 basically allows the second treated water to flow through either the second piping 12 or the second branch pipe 12a by opening and closing. However, when a valve whose opening degree can be adjusted to change the flow rate is used as the second valve V12, the amount of second treated water flowing in the second branch pipe 12a can also be adjusted to a desired amount.

[0044] In this case, for example, the second treated water can be directed primarily to the second pipe 12, with a portion directed to the second branch pipe 12a. Directing a portion of the second treated water to flow to the second branch pipe 12a effectively prevents the second treated water from stagnating in the second branch pipe 12a between the branch point C2 and the second valve V12.

[0045] In addition, even when the second valve V12 is set to a completely closed mode, in order to prevent stagnation, a second release pipe (drainage) that allows a small amount of second treated water to flow and be discharged can be set in the second branch pipe 12a. In this way, the stagnation of the second treated water can also be effectively prevented.

[0046] The third pipe 13 is connected to the first pipe 11 and the second pipe 12 and is a pipe that allows the first treated water and the second treated water to flow. Figure 1AIn FIG, the connection portion with the first pipe 11 and the second pipe 12 is shown as a connection point C3.

[0047] The third pipe 13 is connected to the water quality measuring device 14, described below, and allows the treated water to flow for measurement. This third pipe generally allows either the first treated water or the second treated water to flow. However, when switching between the first and second treated water flow paths, a mixed water mixture of the first and second treated waters may temporarily flow.

[0048] This third piping also includes a connection portion with the first piping 11 and the second piping 12, and does not include a valve such as a switching valve that changes the flow path. Specifically, as described in the prior art, when switching between multiple treated water streams, a switching valve is typically provided at the piping connection portion, and the flow path is switched by using this switching valve to circulate the treated water being measured. Regarding this point, in this embodiment, no such switching valve is provided, thereby suppressing the generation of pollutants (such as particulates) caused by the operation of the switching valve. Furthermore, during switching, the treated water can always flow to the water quality measuring device, enabling stable water quality measurement using the water quality measuring device.

[0049] The water quality measuring device 14 is connected to the third pipe 13 and is a device for measuring the water quality of the treated water flowing through the third pipe 13. That is, in this embodiment, the water quality of both the first treated water and the second treated water can be measured separately.

[0050] As the water quality measuring device 14 , a known water quality measuring system can be used without particular limitation, and the type of the device can be appropriately selected according to desired measurement items in the treated water to be measured.

[0051] In addition, in this embodiment, it is preferred to use highly purified water such as medical water, pure water and ultrapure water as treated water. As the water quality measuring system used at this time, for example, a particle measuring device (particle counter), a microorganism measuring device, etc. can be preferably cited.

[0052] Pharmaceutical water (e.g., purified water, sterilized purified water, water for injection) used in the manufacture of pharmaceuticals and the like is produced by, for example, passing tap water, etc., through a water treatment system such as a reverse osmosis membrane device or an electrical deionizer to remove impurities from the raw water. Pharmaceutical water is subject to specific water quality requirements in accordance with each country's pharmacopoeia, and daily or regular water quality management is required.

[0053] Pure water and ultrapure water are produced by, for example, using tap water as raw water, treating it with a primary pure water device, and further treating it with a secondary pure water device as needed. For example, the resistivity of pure water (primary pure water) is above 17MΩ·cm, and the resistivity of ultrapure water (secondary pure water) is above 18MΩ·cm.

[0054] The primary pure water device and the secondary pure water device for producing pure water and ultrapure water only need to have the same structure as the devices used in the known pure water production devices (ultrapure water production devices). For example, the primary pure water device can be composed of a reverse osmosis membrane device, a degassing device (decarbonation, etc., vacuum degassing device, degassing membrane device, etc.), an ion exchange device (cation exchange resin device, anion exchange resin device, mixed bed ion exchange resin device, etc., electrodeionization device, etc.), and an ultraviolet oxidation device. For example, the secondary pure water device can be composed of an appropriate combination of one or more of the following devices: an ultrafiltration membrane device, a heat exchanger, an ultraviolet oxidation device, a hydrogen peroxide removal device, a degassing membrane device, a non-regenerative mixed bed ion exchange resin device (Polisher), etc., and these devices can be appropriately selected to form the device.

[0055] In addition, in the case where the first branch pipe 11a has the first release pipe and the second branch pipe 12a has the second release pipe, as described above, Figure 1B As shown. Figure 1B The water quality measuring system 10a shown in the figure has the following components in addition to the first release pipe 11b and the second release pipe 12b: Figure 1A The water quality measuring system 10 shown has the same structure.

[0056] [Water quality measurement method]

[0057] Next, the water quality measurement method of this embodiment is described. In this water quality measurement method, the water quality measurement method is described. Figure 1A As an example, the water quality measurement system 10 shown in FIG. Figure 2A and Figure 2B Provide explanation.

[0058] The water quality measurement method of this embodiment comprises: a first supply step of supplying first treated water to a first pipe; a second supply step of supplying second treated water to a second pipe; a switching step of flowing either the first treated water or the second treated water through a third pipe connected to the first and second pipes; and a water quality measurement step of measuring the quality of the treated water flowing through the third pipe. Each step is described in detail below.

[0059] (First Supply Step and Second Supply Step)

[0060] The first supply step in this embodiment is a step of supplying first treated water to the first pipe 11, which has a first branch pipe 11a equipped with a first valve V11. Furthermore, the second supply step in this embodiment is a step of supplying second treated water to the second pipe 12, which has a second branch pipe 12a equipped with a second valve V12.

[0061] The first treated water and the second treated water supplied here are both subject to water quality measurement and are supplied as needed. For example, if the treated water is ultrapure water and water quality measurement is performed in multiple ultrapure water lines, it is preferable to constantly monitor the water quality. Therefore, the first treated water and the second treated water are constantly supplied to the first pipe 11 and the second pipe 12, respectively.

[0062] The first treated water and the second treated water may be the same treated water or different treated water. In the case of different treated water, for example, in multiple ultrapure water production lines, a portion of ultrapure water (treated water) may be sampled from different production lines for water quality measurement and supplied to the first pipe and the second pipe, respectively.

[0063] (Switching process)

[0064] Next, the first valve V11 is closed and the second valve V12 is opened, or the first valve V11 is opened and the second valve V12 is closed, so that either the first treated water or the second treated water flows through the third pipe 13 connected to the first pipe 11 and the second pipe 12. In this specification, "closing" the first valve V11 and the second valve V12 includes not only completely closing them but also throttling the flow path by adjusting the opening and discharging a portion of the treated water.

[0065] That is, when the first valve V11 is closed and the second valve V12 is open, the flow of the first branch pipe 11a is stopped, so the first treated water flows through the first pipe 11 to the third pipe 13. At this time, the second treated water flows through the second pipe 12 to the second branch pipe 12a. Figure 2A As shown, the main flow of the treated water is represented by a thick solid line. Regarding the opening and closing of the valves, the blackened valve (first valve V11) represents closing, and the hollow valve (second valve V12) represents opening.

[0066] In addition, at this time, it is preferable to set the piping structure, flow rate, pressure and other conditions so that the second treated water does not mix into the third piping 13. That is, a part of the first treated water is diverted from the connection point C3 to the branch point C2 ( Figure 2AFor example, a flow sensor (such as a clamp-on flow sensor) can be installed between the branch point C2 and the connection point C3. If such mixing does not occur, it can be confirmed that the first treated water flows from the connection point C3 to the branch point C2.

[0067] The first treated water flowing through the third pipe 13 undergoes water quality measurement via the water quality measuring device 14. As the first treated water flows from the first pipe 11 to the third pipe 13, there are no valves, such as switching valves, on the flow path to the water quality measuring device 14. Therefore, the water quality is not contaminated by valve opening and closing. Furthermore, it is more preferable that the treated water, after being introduced into the water quality measuring system, have no such valves on the flow path until it reaches the water quality measuring device 14.

[0068] Furthermore, since the first treated water flows between connection point C3 and branch point C2, impurities do not adhere to the piping in that section or deteriorate the water quality due to stagnant water caused by flow cessation. This prevents deterioration in measured values ​​due to such contamination when the flow path is subsequently switched to measure the second treated water. Furthermore, the second treated water is directly discharged from the second branch pipe 12a.

[0069] In addition, when the first valve V11 is opened and the second valve V12 is closed, the flow of the second branch pipe 12a is stopped, so the second treated water flows through the second pipe 12 to the third pipe 13. At this time, the first treated water flows through the first pipe 11 to the first branch pipe 11a. Figure 2B As shown, the thick solid line represents the main flow of the treated water. Regarding the opening and closing of the valves, the blackened valve (the second valve V12) represents closing, and the hollow valve (the first valve V11) represents opening.

[0070] In addition, at this time, it is preferable to set the piping structure, flow rate, pressure and other conditions so that the first treated water does not mix into the third piping 13. That is, a part of the second treated water is diverted from the connection point C3 to the branch point C1 ( Figure 2B For example, a flow sensor (such as a clamp-on flow sensor) can be installed between the branch point C1 and the connection point C3. If no such mixing occurs, it can be confirmed that the second treated water flows from the connection point C3 to the branch point C1.

[0071] The second treated water flowing through the third pipe 13 undergoes water quality measurement via the water quality measuring device 14. Since the second treated water flows from the second pipe 12 to the third pipe 13, and there are no valves on the flow path to the water quality measuring device 14, the water quality is not contaminated by the opening and closing of valves. Furthermore, it is more preferable that the treated water, after being introduced into the water quality measuring system, have no such valves on the flow path until it reaches the water quality measuring device 14.

[0072] Furthermore, since the second treated water flows between connection point C3 and branch point C1, impurities adhering to the piping in that section or deteriorating water quality due to stagnant water due to flow cessation are not caused. This prevents deterioration in measured values ​​due to such contamination when the flow path is subsequently switched to measure the first treated water. Furthermore, the first treated water is directly discharged from the first branch pipe 11a.

[0073] In this embodiment, the water quality measurement of the first treated water and the second treated water can determine which treated water is to be flowed into the third pipe 13 by switching the opening and closing of the first valve V11 and the second valve V12 .

[0074] When measuring the quality of the first treated water, the first valve V11 is closed. At this time, the flow rate Q flowing from the branch point C1 to the first pipe 11 is 11 The flow rate Q flowing through the first branch pipe 11a 11a The flow ratio (Q 11 :Q 11a ) is preferably set to 10:0 to 8:2, more preferably to 10:0 to 9:1.

[0075] Similarly, when measuring the water quality of the second treated water, the second valve V12 is closed. At this time, the flow rate Q flowing from the branch point C2 to the second pipe 12 is 12 The flow rate Q flowing through the second branch pipe 12a 12a The flow ratio (Q 12 :Q 12a ) is preferably set to 10:0 to 8:2, more preferably to 10:0 to 9:1.

[0076] It should be noted that, in the above case, the flow rate Q 11a and flow Q 12a It can also be said that it is the flow rate discharged from the branch pipe to the outside by adjusting the opening of the valve or releasing the piping.

[0077] (Water quality measurement process)

[0078] Next, the water quality measuring device 14 measures the water quality of the treated water (first treated water or second treated water) flowing through the third pipe 13 .

[0079] The items to be measured are not particularly limited as long as they can be used as water quality measurement items. For example, the microparticles and microorganisms described in the description of the water quality measurement device 14 are preferred. The items to be measured correspond to the items that can be measured by the water quality measurement device 14 and can be appropriately selected based on the desired water quality of the treated water.

[0080] In this water quality measurement, when measuring microparticles, for example, microparticles with a particle size of 0.2 μm or more, or microparticles with a particle size of 0.05 μm or more, the size of the microparticles to be measured can be determined by setting desired characteristics based on the performance of the measuring device.

[0081] In the above, as a first embodiment, a water quality measurement system and a water quality measurement method have been described. By being able to perform water quality measurement as described above, when switching between the first treated water and the second treated water to measure the water quality, it is possible to do so without setting a switching valve in the branch part, etc., thereby simplifying the device structure.

[0082] Furthermore, since no switching valve is required, no pollutants such as particles are generated by the switching valve. In the water quality measurement of this embodiment, the measurement results can be considered to directly reflect the quality of the treated water, and the measurement results are highly reliable.

[0083] Moreover, when an existing switching valve is installed, there will be many times when the treated water does not flow through the water quality measuring device at the timing of switching the switching valve. However, in the water quality measuring method of this embodiment, there is no such timing when the treated water does not flow, and stable measurement can be performed.

[0084] In this embodiment, the opening and closing of the first valve V11 and the second valve V12 determine which of the first and second treated water flows to the water quality measuring device 14. Therefore, a switching unit is preferably provided to open one of these valves and switch the flow. The switching unit can be switched each time an opening or closing instruction is given, or it can be set to automatically switch at a predetermined time. Furthermore, this switching is preferably performed alternately at predetermined time intervals.

[0085] (Second embodiment)

[0086] Next, refer to Figure 3 A water quality measurement system and a water quality measurement method according to a second embodiment will be described.

[0087] like Figure 3As shown, the water quality measuring system of the second embodiment is a water quality measuring system 20, which is constructed to have: a first pipe 11; a first branch pipe 11a; a second pipe 12; a second branch pipe 12a; a third pipe 13; a water quality measuring device 14; a fourth pipe 21, which can supply the same treated water to the first pipe 11 and the second pipe 12, and has a supply valve V21; and a filter 22, which is arranged on the second pipe 12.

[0088] Here, the same reference numerals are given to the same configurations as those in the first embodiment, and their description is omitted. That is, the characteristic configuration of the second embodiment is the fourth pipe 21 having the supply valve V21 and the filter 22, and the description will focus on the different characteristic portions.

[0089] In this second embodiment, both the first pipe 11 and the second pipe 12 are connected to the fourth pipe 21 on their upstream sides. This connection point is indicated as connection point C4. Furthermore, the fourth pipe 21 is a treated water supply pipe capable of supplying treated water to be measured. That is, in this embodiment, the treated water flowing through the fourth pipe 21 is separated into treated water flowing through the first pipe 11 and treated water flowing through the second pipe 12, resulting in the same treated water flowing through them together. Therefore, in this embodiment, the first treated water and the second treated water are the same treated water.

[0090] Furthermore, the fourth pipe 21 includes a supply valve V21 . The supply valve V21 is a valve that can determine whether or not the treated water can be supplied to the water quality measurement system 20 by opening and closing the valve.

[0091] The filter 22 is provided in the second piping 12 and is a filter capable of capturing the item being measured by the water quality measuring device 14. Specifically, if the water quality measuring device 14 is a particle measuring device, the filter 22 is capable of capturing the target particles, and examples thereof include a microfiltration membrane (MF) and an ultrafiltration membrane (UF). Furthermore, if the water quality measuring device 14 is a microbiological measuring device, the filter 22 is capable of capturing the target microorganisms, and examples thereof include a microfiltration membrane (e.g., a nuclepore membrane, specifically, an HCPS cartridge (manufactured by Nomura Microscience Co., Ltd., trade name)).

[0092] In this embodiment, by adopting the above-described device structure, for the same treated water, the first treated water remains unchanged, while the second treated water is passed through the filter 22 for treatment. Furthermore, the flow of the treated water thereafter is the same as that described in the first embodiment. The first treated water or the second treated water is delivered to the water quality measuring device 14 by opening and closing the first valve V11 and the second valve V12, and the water quality of the treated water is measured.

[0093] With such a configuration, changes in the water quality due to the presence or absence of treatment by the filter 22 can be measured for the treated water.

[0094] By performing water quality measurement in this way, for example, if an adverse condition occurs in the ultrapure water manufacturing process and particles that should not be contained are mixed in, the particles are detected in the first treated water that has not been treated by the filter, and no particles are detected in the second treated water treated by the filter 22 (the number of particles is reduced), thereby determining whether there is an adverse condition in the ultrapure water manufacturing device.

[0095] Furthermore, by performing the water quality measurement described above, it is also possible to cope with fluctuations in the noise level (detection level) of the water quality measuring device 14. Specifically, when a particle measuring device is used as the water quality measuring device 14, if the noise level in the particle measurement results of very pure treated water, such as ultrapure water, is high, it may be difficult to distinguish whether it is noise or the presence of particles.

[0096] However, in this embodiment, even in such a case, it is possible to determine whether the measurement result is a problem with the noise level or a problem with the ultrapure water production device. That is, if there is no problem with the ultrapure water production device, the supplied ultrapure water meets the specified conditions and contains very few particles.

[0097] In this case, if the noise level of the water quality measuring device 14 is very low, both the first treated water and the second treated water will be measured as having very low particle counts. On the other hand, if the noise level of the water quality measuring device 14 is high, both the first treated water and the second treated water will have a slight particle count, but there will be no difference in water quality (particle count) due to the treatment in the filter 22, and the particle count measurement results will be similar.

[0098] On the other hand, if a problem exists in the ultrapure water production apparatus, as described above, particles are detected in the first treated water, but are captured and removed by the filter 22 in the second treated water, resulting in no particles being detected. Furthermore, if the noise level of the water quality measuring device 14 is high, particles may appear to be detected in both the first and second treated waters. However, in this case, the number of particles present in the first treated water is detected in addition to the noise, while only the noise is detected in the second treated water. By comparing these measurement results, it can be determined that a problem has occurred in the ultrapure water production apparatus.

[0099] As described above, in this embodiment, by comparing the water quality measurement results of the first treated water and the second treated water, it is possible to determine whether a malfunction has occurred in the ultrapure water production apparatus without being affected by the noise level of the water quality measurement device.

[0100] In this embodiment, as described above, in order to compare the water quality of the first treated water and the second treated water, it is preferable to alternately measure the water quality of each treated water. To perform such alternating measurements, it is preferable to include a control unit that controls a switching unit that switches the opening and closing of the first valve V11 and the second valve V12 so that they alternately switch at a predetermined time.

[0101] At this time, by setting the first valve V11 and the second valve V12 as automatic valves such as solenoid valves, their opening and closing are switched and controlled at a specified time, the water quality of the first treated water and the second treated water are compared. When the difference in their water quality exceeds the specified range, a notification unit is set to notify and warn, thereby automatically measuring the water quality of the treated water.

[0102] When switching alternately at predetermined intervals, the time interval can be set to a desired length. For example, when continuously monitoring the quality of ultrapure water, the control unit preferably switches the first valve V11 and the second valve V12 alternately every 30 minutes to 24 hours, alternately delivering the treated water for water quality measurement to the water quality measurement device 14. Alternatively, the first treated water and the second treated water may be measured at different times. For example, it is preferable to set the measurement time for the first treated water to 1 day to 1 week, and the measurement time for the second treated water to 30 minutes to 2 hours, with the water being delivered alternately.

[0103] Example

[0104] Hereinafter, the present invention will be further described with reference to examples.

[0105] (Example 1)

[0106] As the water quality measurement system used in this embodiment, a basic structure is prepared. Figure 3 The water quality measuring system 20 described in.

[0107] The water quality measurement system used here includes a first release pipe and a second release pipe, respectively, installed in the first branch pipe 11a and the second branch pipe 12a, which allow the treated water to be discharged and continue to flow when the first valve V11 and the second valve V12 are closed. Flowmeters are installed in these release pipes, the first branch pipe 11a, the second branch pipe 12a, and the third pipe 13. The flowmeters are located after the valves in the first branch pipe 11a and the second branch pipe 12a, and after the water quality measurement device (particle measurement device) 14 in the third pipe. Furthermore, sandwich flow sensors are installed between the branch point C1 and the connection point C3, and between the branch point C2 and the connection point C3.

[0108] The devices and components that make up the water quality measurement system are as follows.

[0109] Water quality measuring device (particle measuring device) 14: PMS, Ultra DI 50 (trade name; minimum measurable particle size 0.05 μm)

[0110] First valve V11, second valve V12: ADK11-15A (trade name; solenoid valve) manufactured by CKD Corporation

[0111] Filter 22: Ultipleat SP DR (trade name; small capsule type (5 nm)) manufactured by Pall Corporation, Japan

[0112] Flow meter: P-060 (trade name) manufactured by Tokyo Keiso Co., Ltd.

[0113] Clamp-on flow sensor: KEYENCE Corporation, FD-X (trade name)

[0114] Separately, ultrapure water was treated in the order of an ultraviolet oxidizer (manufactured by Japan Photoscience Co., Ltd., trade name: JPW2×2; TOC-UV), a polisher (filled with 200 L of N-Lite MBSP), and an ultrafiltration membrane (manufactured by Asahi Kasei Corporation, trade name: OLT-6036VA; UF) at 10 m 3 / hr produces ultrapure water.

[0115] The water quality measuring system is attached to a sampling valve provided at the outlet of the ultrafiltration membrane of the ultrapure water production apparatus, and the ultrapure water produced by the ultrapure water production apparatus is introduced into the water quality measuring system through a fourth pipe.

[0116] The introduced ultrapure water is branched into the first and second pipes as first treated water and second treated water, respectively. With the first valve of the water quality measurement system closed and the second valve open, the first treated water flows into the third pipe. The second treated water, after being treated by the filter, flows into the second branch pipe. The quality of the first treated water is then measured using the water quality measurement device.

[0117] At this time, the clamp-on flow sensor confirmed that the first treated water was flowing from branch point C1 to connection point C3, and that the remaining first treated water was flowing from connection point C3 to branch point C2 at a rate of 0.2 L / min. Furthermore, the flow rate confirmed by the flow meter was approximately 0.1 L / min in the first discharge pipe, 0 L / min in the first branch pipe, 1 L / min in the third pipe, 1.5 L / min in the second branch pipe, and 0.1 L / min in the second discharge pipe.

[0118] Next, the first valve and the second valve are switched on and off in a manner such that the first valve is open and the second valve is closed. The first treated water flows to the first branch pipe side, and the second treated water is treated by the filter and flows to the third pipe. The water quality of the second treated water is measured using a water quality measuring device.

[0119] At this time, the clamp-on flow sensor confirmed that the second treated water was flowing from branch point C2 to connection point C3, and that the remaining second treated water was flowing from connection point C3 to branch point C1 at a rate of 0.2 L / min. Furthermore, the flow rate confirmed by the flow meter was approximately 0.1 L / min in the first discharge pipe, 1.5 L / min in the first branch pipe, 1 L / min in the third pipe, 0 L / min in the second branch pipe, and 0.1 L / min in the second discharge pipe.

[0120] As described above, the operation of switching the first valve and the second valve was repeated every 8 hours, and the number of particles at this time was measured at intervals of 1 minute using a particle counting device. The measurement results are shown in FIG. Figure 4 At this time, the diameter of the particle measuring device is set to 0.05 μm to detect particles with a diameter greater than 0.05 μm. Figure 4 In FIG. 1 , the time during which the water quality of the first treated water is measured is set as W1, and the time during which the water quality of the second treated water is measured is set as W2, and their lengths are represented by the lengths of the lines indicated by the two arrows.

[0121] The measurement results showed that almost no particles were detected in the ultrapure water, regardless of whether or not the water was filtered. The average particle count of the first treated water without filtering was approximately 0.5 particles / L, indicating very good water quality. This indicates that the ultrapure water production equipment is functioning normally.

[0122] (Example 2)

[0123] The same ultrapure water production apparatus and water quality measurement system as in Example 1 were used to perform water quality measurement in the same manner. In addition, this example is an example of a case where particles are mixed into the ultrapure water produced by the ultrapure water production apparatus. The results of the particle measurement are shown in FIG. Figure 5 .

[0124] According to the measurement results, almost no particles were detected in the second treated water, which had been filtered, but a large number of particles were detected in the first treated water, which had not been filtered. The average particle count in the first treated water, which had not been filtered, was approximately 500 particles / L, indicating a high concentration of particles. This is believed to be due to a malfunction in the ultrapure water production equipment, which has led to the incorporation of particles. This can be used to determine the timing for repairs and maintenance of the ultrapure water production equipment.

[0125] (Example 3)

[0126] The same ultrapure water production device and water quality measurement system as in Example 1 were used to perform water quality measurement in the same manner. The results of the particle measurement are shown in FIG. Figure 6 .

[0127] The measurement results show that minute amounts of particles were detected in the ultrapure water, regardless of whether or not the water was filtered. In this case, the average particle count of the unfiltered first-processed water was approximately 25 particles / L, making it difficult to determine whether this was due to noise from the particle measurement device or the presence of minute particles. However, in this example, the same trend was observed in the filtered first-processed water, indicating that the noise level of the water quality measurement device was high. This suggests that the ultrapure water production system itself is functioning normally.

[0128] Based on the above, according to this embodiment, in the water quality measurement of the first treated water and the second treated water, when switching the measurement object, a flow path switching valve is not provided on the flow path connected to the water quality measurement device of the treated water, thereby simplifying the device structure and being able to perform the measurement without going through the flow path switching valve, so that the treated water supplied to the water quality measurement device will not be interrupted, and the water quality measurement can be performed stably.

[0129] In addition, according to this embodiment, as described above, the treated water to be measured does not pass through the flow path switching valve, so particles caused by the operation of the flow path switching valve will not be generated. In addition, it is not easy to generate accumulated water retained in the piping, and the contamination of the treated water caused by them can be suppressed, so the water quality can be measured accurately and stably.

[0130] Explanation of symbols

[0131] 10, 20…Water quality measurement system

[0132] 11…First piping

[0133] 11a…First branch pipe

[0134] 11b…First release pipe

[0135] V11…the first valve

[0136] 12…Second piping

[0137] 12a…Second branch pipe

[0138] 12b…Second release pipe

[0139] V12…Second valve

[0140] 13…Third piping

[0141] 14…Water quality measuring device

[0142] 21…Fourth pipe

[0143] Ⅴ21…Supply valve

[0144] 22…Filter

[0145] C1, C2…branch points

[0146] C3, C4...connection points

Claims

1. A water quality measurement system, characterized in that: The invention comprises: a first pipe for circulating first treated water; a first branch pipe branching from the first pipe and having a first valve; a second pipe for circulating second treated water; a second branch pipe branching from the second pipe and having a second valve; a third pipe connected to the first pipe and the second pipe for circulating the first treated water and the second treated water; and a water quality measuring device for measuring the water quality of the treated water circulating in the third pipe, wherein the third pipe includes a connection portion with the first pipe and the second pipe and does not have a valve.

2. The water quality measurement system according to claim 1, characterized in that: A switching unit is provided for switching the opening and closing of the first valve and the second valve so that one is open and the other is closed.

3. The water quality measurement system according to claim 1, characterized in that: The water quality measuring device is a particle measuring device or a microorganism measuring device.

4. The water quality measurement system according to claim 1, characterized in that: The first pipe and the second pipe are connected to a fourth pipe for supplying one treated water so as to flow the same treated water, and the second pipe is provided with a filter capable of capturing particles and microorganisms.

5. The water quality measurement system according to claim 4, characterized in that: The filter is a microfiltration membrane or an ultrafiltration membrane capable of capturing particles, and the water quality measuring device is a particle measuring device.

6. The water quality measurement system according to any one of claims 1 to 5, characterized in that: A control unit is provided for repeatedly switching the opening and closing of the first valve and the second valve alternately at a predetermined time.

7. A method for measuring water quality, characterized in that: The invention comprises: a first supply process of supplying first treated water to a first pipe having a first branch pipe with a first valve; a second supply process of supplying second treated water to a second pipe having a second branch pipe with a second valve; a switching process of closing the first valve and opening the second valve, or opening the first valve and closing the second valve, so that one of the first treated water or the second treated water flows to a third pipe connected to the first pipe and the second pipe; and a water quality measuring process of measuring the water quality of the first treated water or the second treated water flowing in the third pipe, wherein the third pipe includes a connection portion with the first pipe and the second pipe and does not have a valve.

8. The water quality determination method according to claim 7, characterized in that: The switching step includes a control step of alternately repeating a state in which the first valve is closed and the second valve is opened, and a state in which the first valve is opened and the second valve is closed, at a predetermined time.

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