Measurement system and measurement method for water treatment device

Abstract

A measurement system 50 for a water treatment device has: a plurality of water collection pipes L4 for collecting water subject to measurement; a measurement pipe L5 formed by merging the plurality of water collection pipes L4; at least one measurement device 11 disposed on or connected to the measurement pipe L5, the at least one measurement device 11 measuring the water quality of the water subject to measurement; a plurality of blow pipes L8 respectively branched from each of the plurality of water collection pipes L4; and a plurality of water collection switching valves V3 that are respectively provided to each of the plurality of water collection pipes L4 and are positioned downstream of branching parts P3 at which the blow pipes L8 branch.

Description

Measurement system and measurement method for water treatment equipment

[0001] This application is based on and claims priority from Japanese Patent Application No. 2024-88901, filed May 31, 2024, which is incorporated herein by reference in its entirety.

[0002] The present invention relates to a measurement system and a measurement method for a water treatment device.

[0003] When measuring the quality of water flowing through a water treatment device at multiple measurement locations, it is desirable to share the same type of measurement device to prevent costs from increasing. Japanese Patent Application Laid-Open Publication No. 2014-185904 describes a method for measuring water sampled from two pipes using a common particle meter. Two water sampling pipes and a measurement pipe equipped with a particle meter are connected by a three-way valve, and by switching the three-way valve, the quality of the water flowing through either of the water sampling pipes can be measured. A blow-off pipe is connected to each water sampling pipe, and a portion of the water that flows into the water sampling pipe not being measured is discharged.

[0004] The measurement method described in JP 2014-185904 A uses a three-way valve to switch between two water sampling pipes, so when measuring the water to be measured sampled in the first water sampling pipe and then switching the three-way valve to measure the water to be measured in the second water sampling pipe, the water to be measured sampled in the first water sampling pipe may remain as pooled water inside the three-way valve, or the inside of the three-way valve may become contaminated by this pooled water, lengthening the start-up time until the water to be measured in the second water sampling pipe can be measured. The present invention aims to provide a measurement system for a water treatment device that can reduce the start-up time until the water to be measured can be measured.

[0005] The measurement system of the water treatment device of the present invention comprises a plurality of water sampling pipes for sampling the water to be measured, a measurement pipe formed by the merging of the plurality of water sampling pipes, at least one measurement device arranged or connected to the measurement pipes for measuring the water quality of the water to be measured, a plurality of blow pipes branching off from each of the plurality of water sampling pipes, and a plurality of water sampling switching valves provided on each of the plurality of water sampling pipes and located downstream of the branching portion of the blow pipe.

[0006] According to the present invention, it is possible to provide a measurement system for a water treatment device that can reduce the rise time required for measurement of the water to be measured.

[0007] The above and other objects, features, and advantages of the present application will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, which illustrate the present application.

[0008] FIG. 1 is a schematic diagram of a measurement system according to a first embodiment of the present invention. FIG. 2 is an enlarged view of part A in FIG. 1. FIG. 3 is an enlarged view of part A of a measurement system according to a second embodiment of the present invention. FIG. 4 is a schematic diagram showing the open / closed state of the inlet valve and the flow of the water to be measured in FIG. 3. FIG. 5 is a schematic diagram of a test device used in Example 1. FIG. 6 is a schematic diagram of a test device used in Example 2. FIG. 7 is a graph showing the relationship between the linear velocity of the water to be measured and water quality parameters in Example 2 (measurement results of UDI-20). FIG. 8 is a graph showing the relationship between the linear velocity of the water to be measured and water quality parameters in Example 2 (measurement results of UDI-50).

[0009] Referring to the drawings, an embodiment of a measurement system and a measurement method for a water treatment device according to the present invention will be described. FIG. 1 is a schematic diagram showing a portion of a water treatment device 100 according to a first embodiment of the present invention. The water treatment device 100 of this embodiment is an ultrapure water production device. The ultrapure water production device includes a pretreatment device (not shown), a primary pure water system (not shown) connected to the pretreatment device, and a secondary pure water system (hereinafter referred to as subsystem 1) connected to the primary pure water system, and produces ultrapure water used in the manufacturing process of electronic components such as semiconductors.

[0010] Subsystem 1 includes at least one pure water tank 2, at least one pure water supply pump 3, at least one heat exchanger 4, at least one ultraviolet oxidation device 5, at least one ion exchange device 6, at least one membrane degassing device 7, and ultrafiltration membrane device 8 (these may be referred to as devices 2 to 8), which are arranged in the above order on mother pipe L1 along the flow direction D of the water to be treated. When any of devices 2 to 8 includes multiple devices, the multiple devices are arranged in parallel, in series, or a combination thereof. Mother pipe L1 is connected to a use point 9, and ultrapure water produced in subsystem 1 is supplied to the use point 9. Ultrapure water not used at the use point 9 is returned to the pure water tank 2 through a return pipe L2 connected to mother pipe L1. The configuration of subsystem 1 is not limited to the above configuration; for example, the membrane degassing device 7 may be omitted.

[0011] The pure water tank 2 stores pure water produced in the primary pure water system. The pure water supply pump 3 supplies the pure water stored in the pure water tank 2 to the heat exchanger 4. The ultraviolet oxidation device 5 irradiates the pure water whose temperature has been adjusted in the heat exchanger 4 with ultraviolet light to decompose organic matter contained in the pure water. The ion exchange device 6 removes ionic components from the pure water. The ion exchange device 6 is a non-regenerative cartridge polisher filled with a mixed bed of cation exchange resin and anion exchange resin. The membrane degassing device 7 degasses the pure water, i.e., removes dissolved oxygen and carbon dioxide contained in the pure water. The ultrafiltration membrane device 8 finally removes fine particles contained in the pure water.

[0012] The water quality measurement system 50 provided in the subsystem 1 will be described with reference to Figure 2. Figure 2 shows an enlarged view of part A in Figure 1. In the subsystem 1, it is desirable not only to measure the quality of the ultrapure water supplied to the point of use 9, but also to monitor the status of the devices 2 to 8. If any of the devices 2 to 8 includes multiple devices, it is also desirable to monitor the status of each device. For this reason, the subsystem 1 has various types of measurement devices 11 at various measurement positions. Here, the measurement system 50 for measuring the outlet water of the ultrafiltration membrane device 8 will be described as an example.

[0013] The ultrafiltration membrane device 8 includes two ultrafiltration membrane modules 8A and 8B arranged in parallel. Specifically, the main pipe L1 branches into two pipes L3, each containing an ultrafiltration membrane module 8A or 8B. The two pipes L3 merge back into the main pipe L1 at a junction P1. The measurement system 50 includes multiple water sampling pipes L4 for sampling the water to be measured. The multiple water sampling pipes L4 branch off from the two pipes L3 at a water sampling point P2 between the ultrafiltration membrane modules 8A and 8B and the junction P1, and sample the outlet water of the ultrafiltration membrane modules 8A and 8B as the water to be measured. As described in Example 2, the linear velocity (hereinafter referred to as LV) of the water to be measured flowing through the water sampling pipes L4 is preferably 0.6 m / s or higher, and more preferably 0.8 m / s or higher. Even when there is only one water sampling point, the LV is preferably 0.6 m / s or more, and more preferably 0.8 m / s or more. The water sampling point P2 is set to monitor the operating state and deterioration of each of the ultrafiltration membrane modules 8A and 8B, but the water sampling point is not limited to this and can be set appropriately depending on the purpose. For example, to check the quality of the ultrapure water supplied to the use point 9, the water to be measured can be sampled downstream of the confluence P1 of the two pipes L3.

[0014] Multiple water sampling pipes L4 merge to form a single measurement pipe L5. When there are three or more water sampling pipes L4, the water sampling pipes L4 may merge at a single location or sequentially at multiple locations. The water sampling pipe L4 refers to a single section that does not merge with other water sampling pipes L4. In other words, the water sampling pipe L4 is a section downstream of the water sampling point P2 and upstream of the most upstream junction of the water sampling pipe L4 and other water sampling pipes L4. The measurement pipe L5 refers to a section downstream of the point where all water sampling pipes L4 merge. The measurement pipe L5 includes a main pipe L6 and at least one (multiple in this embodiment) branch pipe L7 connected to the main pipe L6. A measurement device 11 that measures the water quality of the measurement water is disposed in each of the at least one (multiple in this embodiment) branch pipe L7. In other words, the measurement system 50 includes at least one (multiple in this embodiment) measurement device 11 connected to the measurement pipe L5. The measurement device 11 may be disposed on the measurement pipe L5. In this embodiment, three different measuring devices 11 are arranged in the three branch pipes L7, but there are no limitations on the type or number of the measuring devices 11. Examples of the measuring devices 11 include, but are not limited to, a particle counter, a total organic carbon measuring device (hereinafter referred to as a TOC meter), an electrical resistivity meter, a dissolved oxygen concentration meter, and a urea concentration meter.

[0015] Some measuring devices 11 require the supply of measurement water at a predetermined flow rate. The flow rate of the water sampling pipe L4 may be affected by pressure and flow rate fluctuations in the main pipe L1. To suppress flow rate fluctuations of the measurement water supplied to the measuring devices 11, the main pipe L6 is equipped with a pressure regulating valve V1. The pressure regulating valve V1 is preferably located downstream of the connection point of each branch pipe L7 with the main pipe L6, thereby suppressing flow rate fluctuations for all measuring devices 11. A back-pressure valve that automatically operates to maintain constant pressure upstream is preferably used as the pressure regulating valve V1. Each of the multiple branch pipes L7 has a flow regulating valve V2 downstream of the measuring device 11. Pressure fluctuations in the measurement pipe L5 (e.g., pressure fluctuations during flow path switching, as described below) are suppressed by the pressure regulating valve V1, and the flow regulating valve V2 can adjust the flow rate of the measurement water supplied to each measuring device 11. More specifically, the pressure regulating valve V1 suppresses pressure fluctuations in the measurement pipe L5 during flow path switching, thereby reducing the impact on the measuring device 11. Since pressure fluctuations in the measurement pipe L5 are reduced when switching the flow path, the flow rate through the flow control valve V2 also becomes constant. If only the flow control valve V2 is provided, there is a possibility that a flow rate different from the set value will flow if the pressure in the measurement pipe L5 fluctuates significantly.

[0016] The measurement system 50 has multiple water sampling switching valves V3 provided on each of the multiple water sampling pipes L4. The measurement device 11 sequentially measures the water quality of the measurement water sampled at each water sampling point P2. Therefore, only one water sampling switching valve V3 of the multiple water sampling pipes L4 connected to the measurement pipe L5 is open, and the rest are closed. This prevents the measurement of the water quality of a mixture of measurement water sampled at multiple water sampling points P2. Alternatively, all water sampling switching valves V3 may be closed when the measurement device 11 is not performing measurements. The water sampling switching valves V3 may be switched manually or automatically. When the water sampling sequence is determined, it is preferable to automatically switch the water sampling switching valves V3 using the control device 12 of the measurement system 50. The control device 12 is connected to the measurement devices 11 and the water sampling switching valves V3, and the measurement times of each measurement device 11 are pre-stored in the control device 12. When the set measurement time has elapsed, the control device 12 closes the water sampling switching valve V3 of the water sampling pipe L4 for which water quality measurement has been completed, and according to the water sampling sequence, opens the water sampling switching valve V3 of the water sampling pipe L4 for which water quality measurement will be performed next, and commands the measuring device 11 for which water quality measurement will be performed next to perform measurement. When the water quality measurement of the water to be measured sampled at one water sampling point P2 has been completed, the measuring device 11 may notify the control device 12 of this fact.

[0017] A water sampling switching valve V3 is provided for each water sampling pipe L4. In other words, the water sampling switching valve V3 is not shared among multiple water sampling pipes L4. The water sampling switching valve V3 is not limited to any valve that functions as a stop valve (or shut-off valve, or shut-off valve) that can be fully closed, and examples of the valve type include a globe valve, gate valve, and ball valve. When the water sampling switching valve V3 is closed, the measured water is not supplied to the measurement pipe L5 from the water sampling pipe L4, and only the measured water from one water sampling pipe L4 is supplied to the measurement pipe L5. For example, in a configuration in which multiple water sampling pipes are switched using a multi-way valve as in Patent Document 1, the measured water is likely to mix within the multi-way valve. Because stop valves have a simpler structure and are less susceptible to leakage than multi-way valves, the measured water measured by the measurement device 11 is not mixed with the measured water from other water sampling pipes L4, making it easier to reduce measurement errors associated with mixing of multiple measured waters.

[0018] The measurement system 50 has multiple blow pipes L8 branching from each of the multiple water intake pipes L4. Because each water intake switching valve V3 is closed for a long period of time, non-fluidized stagnant water forms within the water intake pipes L4. When stagnant water forms within the water intake pipes L4, impurities derived from the piping materials (metal, plastic, etc.) leach out from the liquid-contacting portions of the water intake pipes L4 and remain in the stagnant water, gradually deteriorating the quality of the stagnant water. Therefore, as described in Example 1, after switching the water intake pipes L4, it takes a long time for the quality of the measurement water to stabilize. This is particularly problematic when ultrapure water is being measured. When the water intake switching valve V3 of a water intake pipe L4 that is not being measured is closed, a portion of the water in that water intake pipe L4 is discharged through the blow pipe L8, fluidizing the water in that water intake pipe L4. This allows impurities resulting from leaching to be discharged from the water intake pipes L4, stabilizing the quality of the measurement water within a short time after opening the water intake switching valve V3.

[0019] The water sampling switch valve V3 is located downstream of the branch point P3 of the blow pipe L8. Therefore, even after the water sampling switch valve V3 is closed, water is always in a flowing state in the section from the water sampling point P2 of the water sampling pipe L4 to the branch point P3 of the blow pipe L8. Conversely, after the water sampling switch valve V3 is closed, the section in the water sampling pipe L4 where water does not flow and remains is limited to the section from the branch point P3 of the blow pipe L8 to the measurement pipe L5. Therefore, after the water sampling switch valve V3 is opened, the water quality of the water sampling pipe L4 quickly stabilizes, making it possible to measure the water quality in a short time.

[0020] The measurement system 50 has multiple blow-off switching valves V4 provided on each blow-off pipe L8. When the measurement water flowing through the water sampling pipe L4 that is not connected to the measurement pipe L5 is discharged, the blow-off switching valve V4 provided on the water sampling pipe L4 that is not connected to the measurement pipe L5 is opened. For example, by keeping the blow-off switching valve V4 constantly open, even when the water sampling switching valve V3 is closed, water always flows in the section of the water sampling pipe L4 from the water sampling point P2 to the branch point P3 of the blow-off pipe L8. As an alternative, the blow-off switching valve V4 can be closed when the water sampling pipe L4 is not connected to the measurement pipe L5, and then opened before the water sampling pipe L4 is connected to the measurement pipe L5. For example, when a single measurement device 11 performs measurements by switching between multiple water sampling pipes L4, water is wastefully discharged from the blow-off pipe L8 of each water sampling pipe L4 for a long period of time. Furthermore, when the water sampling pipes L4A and L4B sample water from different subsystems 1, it is preferable not to open the blow selector valve V4 of the blow pipe L8 branching off from the water sampling pipe L4A and the blow selector valve V4 of the blow pipe L8 branching off from the water sampling pipe L4B simultaneously. If both valves are open, water may backflow into the water sampling pipe L4A or L4B of the subsystem 1 with lower water pressure. In this embodiment, because the water sampling pipes L4A and L4B sample water from the same subsystem 1, backflow is virtually eliminated. The amount of water discharged can be reduced by starting water discharge from the blow pipe L8 in accordance with the timing of measurement. Because the timing for starting water discharge from the blow pipe L8 varies depending on the measuring device 11, it is preferable to measure the time required for water quality stabilization in advance. When the water sampling sequence is determined, it is preferable for the control device 12 to control the timing for opening the blow selector valve V4 connected to the control device 12.

[0021] The measurement system 50 has a recovery pipe L9 connected to at least one of the main pipe L6, the plurality of branch pipes L7, and the plurality of blow pipes L8. As shown in Fig. 1, the recovery pipe L9 is connected to the pure water tank 2, and water discharged from at least one of the main pipe L6, the plurality of branch pipes L7, and the plurality of blow pipes L8 is returned to the pure water tank 2 as recovered water. The return destination of the recovered water is not limited to the pure water tank 2, and may be any location upstream of the pure water tank 2. A recovery tank 51 may be provided in the recovery pipe L9, and the recovered water may be temporarily stored in the recovery tank 51.

[0022] Next, a measurement method for a water treatment device, particularly a method for measuring the quality of ultrapure water, using the measurement system 50 described above will be described. Specifically, the water intake switching valve V3 of the water intake pipe L4 to be measured is opened, measurement water is sampled from the water intake pipe L4, and the sampled measurement water is supplied to the measurement pipe L5. Next, the measurement device 11 disposed on the measurement pipe L5 measures the quality of the measurement water. When the measurement is completed, the water intake switching valve V3 is closed, and the water intake switching valve V3 of the next measurement target water intake pipe L4 is opened, and the same process is performed. Thereafter, the same process is repeated until measurements of all measurement targets are completed. That is, measurement water is sequentially sampled from multiple water intake pipes L4, and the measurement water sampled from the multiple water intake pipes L4 is sequentially supplied to the measurement pipe L5. At this time, the water intake switching valves V3 provided on each of the multiple water intake pipes L4 are opened and closed to sequentially switch the water intake pipe L4 communicating with the measurement pipe L5. The water to be measured flowing through the water sampling pipe L4, which does not communicate with the measurement pipe L5, is discharged through the blow pipe L8, which branches off from the water sampling pipe L4 upstream of the water sampling switching valve V3. Note that the pressure adjustment valve V1 and the flow rate adjustment valve V2 do not generally require operation except during maintenance.

[0023] Second Embodiment FIG. 3 shows an enlarged view of portion A in FIG. 1 of a water treatment device according to a second embodiment. The configuration and effects not described are the same as those of the first embodiment. Each of the multiple water intake pipes L4 has an inlet valve V5 between the water intake point P2 of the water intake pipe L4 and the water intake switching valve V3. The blow-off pipe L8 branches off from the water intake pipe L4 downstream of the inlet valve V5. In this embodiment, as in the first embodiment, measurement water is sequentially sampled from the multiple water intake pipes L4, and the sampled measurement water from the multiple water intake pipes L4 is sequentially supplied to the measurement pipes L5. In this case, the multiple inlet valves V5 provided on each of the multiple water intake pipes L4 are opened and closed to sequentially switch the water intake pipes L4 communicating with the measurement pipes L5. The water intake switching valve V3 and the blow-off switching valve V4 are open except during maintenance, and therefore can be omitted.

[0024] Figure 4 shows the open / closed states of multiple inlet valves V5 and the flow of water to be measured at one point during measurement. Hereinafter, the inlet valves V5 and the water sampling pipe L4 corresponding to the ultrafiltration membrane modules 8A and 8B are distinguished by the designations A and B. In Figure 4, the inlet valve V5A is open and the inlet valve V5B is closed. A portion of the water to be measured flowing through the water sampling pipe L4A flows into the measurement pipe L5, while the remainder flows into the water sampling pipe L4B, flows into the blow pipe L8 just before the inlet valve V5B, and is then discharged. The section of the water sampling pipe L4B where water does not flow and remains is limited to the section from the water sampling point P2 to the branch point P3 of the blow pipe L8. Therefore, after opening the inlet valve V5B, the water quality of the water sampling pipe L4B quickly stabilizes, enabling water quality measurement in a short time. In this embodiment, both the blow switch valve V4 of the blow pipe L8 branching from the water sampling pipe L4A and the blow pipe L8 branching from the water sampling pipe L4B are open. However, in order to reduce the amount of drainage from the blow pipe L8, the blow switching valve V4 of the blow pipe L8 branching off from the water sampling pipe L4A may be closed.

[0025] Example 1 The present invention will be described in more detail with reference to an example. Figure 5 shows a schematic diagram of the test equipment used in Example 1. Water to be treated flowing through a 65A diameter ultrapure water polyvinylidene fluoride pipe L11 was treated by an ultrafiltration membrane device 8, and a portion of the treated water from the ultrafiltration membrane device 8 was collected as measurement water through a branch pipe L12 made of hard polyvinyl chloride for ultrapure water. The flow rate of the measurement water was set to 12 L / min. The branch pipe L12 branched into a first polypropylene pipe L13 and a second polypropylene pipe L14, which merged downstream to form the measurement pipe L15. The measurement water was alternately supplied to the first pipe L13 and the second pipe L14 by operating a first valve V11 and a second valve V12 provided in the first pipe L13 and the second pipe L14, respectively. The first pipe L13 was made by combining bent pipes and had a total length of approximately 100 m to evaluate the influence of stagnant water. The first pipe L13 simulated the water sampling pipe L4 of the embodiment, and the second pipe L14 simulated another water sampling pipe L4. The first valve V11 and the second valve V12 simulated the water sampling switching valve V3 of the embodiment. The volume of the first pipe L13 was 20 L, and the volume of the second pipe L14 was 0.2 L. Because the capacity of the second pipe was sufficiently smaller than that of the first pipe, the influence of stagnant water in the second pipe L14 was negligible. A blow pipe L18 was provided branching off from the first pipe L13 immediately upstream of the first valve V11, and a blow switching valve V13 was provided in the blow pipe L18.

[0026] The measurement pipe L15 has a main pipe L16 and a plurality of branch pipes L17 branching from the main pipe L16, and a plurality of measurement devices 11 consisting of a TOC meter and a particle counter are arranged in the branch pipe L17. An M500e manufactured by Sievers was used as the TOC meter, and a UDI-20 manufactured by PMS was used as the particle counter.

[0027] Table 1 shows the results of Example 1. The measuring device 11 whose measurement results were affected is indicated by a circle. First, starting with the first valve V11 open, the second valve V12 closed, and the blow-off switching valve V13 closed, the first valve V11 was closed, the second valve V12 was opened, and the water quality of the measured water flowing through the second pipe L14 was measured. After this state was maintained for 44 hours, the first valve V11 was opened, the second valve V12 was closed, and the water quality of the measured water flowing through the first pipe L13 was measured (operation pattern 1). The blow-off switching valve V13 was kept closed. The measuring device 11 whose measurement results were affected was the particle counter. The water quality stabilized in approximately 5 hours.

[0028] Next, the first valve V11 was closed, the second valve V12 was opened, and the quality of the measurement water flowing through the second pipe L14 was measured. After this state was maintained for 15 hours, the first valve V11 was opened, the second valve V12 was closed, and the quality of the measurement water flowing through the first pipe L13 was measured (operation pattern 2). The blow-down switching valve V13 was kept closed. The measuring device 11 that affected the measurement results was the TOC meter, and the water quality stabilized in about 2 hours.

[0029] Next, the first valve V11 was closed, the second valve V12 and the blow-off switching valve V13 were opened, and the water quality of the measurement water flowing through the second pipe L14 was measured. The discharge flow rate from the blow-off pipe L18 was set to 1 / 10 of the water intake flow rate. After this state was maintained for 8 hours, the first valve V11 was opened, the second valve V12 was closed, and the water quality of the measurement water flowing through the first pipe L13 was measured (operation pattern 3). No measurement device 11 affected the measurement results, and the water quality stabilized in about 2 minutes.

[0030] As can be seen from the above results, when the measurement water was not discharged from the blow pipe L18 (operation patterns 1 and 2), it took a long time for the measurement results of the measurement water in the first pipe L13 to stabilize. Furthermore, comparing operation patterns 1 and 2, the longer the time that water flowed through the second pipe L14 (i.e., the time that water flow stopped in the first pipe L13), the longer the time until the water quality stabilized. This suggests that the main cause of the deterioration in water quality was the piping material eluting from the first pipe L13. In contrast, when water was discharged from the blow pipe L18 (operation pattern 3), it took very little time for the water quality to stabilize. This is thought to be because the piping material eluted from the first pipe L13 flowed within the first pipe L13 and was largely discharged. Therefore, in order to shorten the time until the measurement results stabilize, it is effective to discharge a portion of the water in the first pipe L13 that is not being measured from the blow pipe L18.

[0031] Next, as in operation patterns 1 and 2, water was not discharged from the blow pipe L18. Instead, water was passed through the second pipe L14 for 5 minutes, and then switched to the first pipe L13 and passed through for 7 minutes (operation pattern 4). The water quality immediately stabilized. This indicates that if the time during which water is not flowing through the first pipe L13 is short, it is not necessary to discharge water from the blow pipe L18. However, this method is practically difficult when switching between multiple first pipes L13 sequentially, because it is difficult to shorten the time during which water is not flowing through the first pipe L13.

[0032]

[0033] Example 2 Next, the relationship between the LV and water quality of the measurement water flowing through the first pipe L13 was investigated. Figure 6 shows a schematic diagram of the test equipment used in Example 2. The configuration of the test equipment was generally the same as in Example 1, except that the second pipe L14 and the blow pipe L18 were omitted, and the same measuring device 11 was placed at the inlet and outlet of the first pipe L13. The LV of the first pipe L13 was varied from 0.2 to 1.2 m / s by changing the flow rate of the measurement water. The water quality parameter was the number of particles. PMS UDI-20 and UDI-50 particle counters were used. The UDI-20 and UDI-50 have different minimum measurable particle sizes, the former being 20 nm and the latter being 50 nm. Figures 7A and 7B show the results. The vertical axis represents the water quality parameter at the outlet of the first pipe L13 minus the water quality parameter at the inlet of the first pipe L13.

[0034] The number of particles decreased as the LV increased. In other words, the water quality improved as the LV increased. The number of particles varied slightly depending on the measuring device 11. With the UDI-20, the increase in the number of particles was suppressed at an LV of 0.8 m / s or more, and with the UDI-50, the increase in the number of particles was suppressed at an LV of 0.6 m / s or more.

[0035] Although several embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. For example, although not shown, the water treatment device 100 may include multiple parallel subsystems 1 shown in FIG. 1 . In this case, the measuring device 11 may be shared by multiple subsystems 1. That is, the water intake pipe L4 may be the water intake pipe L4 of one subsystem 1, or may be the water intake pipe L4 of multiple subsystems 1. For example, if two subsystems 1 are provided, each of which includes three ultrafiltration membrane devices 8, the present invention also includes measuring the water quality of the outlet water from six ultrafiltration membrane devices 8 with a single measuring device 11.

[0036] While several preferred embodiments of the present invention have been shown and described in detail, it will be understood that various changes and modifications can be made therein without departing from the spirit or scope of the appended claims.

[0037] REFERENCE SIGNS LIST 1 Subsystem 11 Measuring device 12 Control device 50 Measuring system 100 Water treatment device L4 Water sampling pipe L5 Measuring pipe L6 Main pipe L7 Branch pipe L8 Blow pipe L9 Recovery pipe V1 Pressure regulating valve V2 Flow rate regulating valve V3 Water sampling switching valve V4 Blow switching valve V5 Inlet valve

Claims

1. A measurement system for a water treatment device comprising: a plurality of water sampling pipes for sampling water to be measured; a measurement pipe formed by the merging of the plurality of water sampling pipes; at least one measurement device disposed on or connected to the measurement pipes for measuring the water quality of the water to be measured; a plurality of blow pipes branching off from each of the plurality of water sampling pipes; a plurality of water sampling switching valves provided on each of the plurality of water sampling pipes and located downstream of the branching portion of the blow pipe; and a plurality of blow switching valves provided on each of the plurality of blow pipes.

2. The measurement system according to claim 1, wherein the measurement pipe has a main pipe and at least one branch pipe connected to the main pipe, the at least one measurement device is disposed in the at least one branch pipe, and the main pipe has a pressure regulating valve downstream of a connection point between the at least one branch pipe and the main pipe.

3. The measurement system of claim 2, wherein said at least one branch pipe has a flow control valve downstream of said measurement device.

4. A measurement system as described in claim 2 or 3, which has a recovery pipe connected to at least one of the main pipe, the at least one branch pipe, and the plurality of blow pipes, and the recovery pipe returns water discharged from at least one of the main pipe, the at least one branch pipe, and the plurality of blow pipes upstream of the water sampling points of the plurality of water sampling pipes.

5. A measurement system according to any one of claims 1 to 4, wherein each of the plurality of water sampling pipes has an inlet valve, and the blow pipe branches off from the water sampling pipe downstream of the inlet valve.

6. A measurement system as described in any one of claims 1 to 5, which has a control device that controls the blow switching valve provided on the water sampling pipe so that the blow switching valve is closed when the water sampling pipe is not connected to the measurement pipe, and the blow switching valve provided on the water sampling pipe is opened before the water sampling pipe is connected to the measurement pipe.

7. A measurement method for a water treatment device, comprising: sequentially collecting water to be measured from a plurality of water sampling pipes; sequentially supplying the water to be measured collected from the plurality of water sampling pipes to a measurement pipe; and measuring the water quality of the water to be measured using at least one measuring device arranged in the measurement pipe, wherein the water sampling pipes communicating with the measurement pipes are sequentially switched by opening and closing a plurality of water sampling switching valves provided in each of the plurality of water sampling pipes, the water to be measured flowing through the water sampling pipes not communicating with the measurement pipes is discharged through a blow pipe branching from the water sampling pipe upstream of the water sampling switching valve, and a blow switching valve is provided in each of the blow pipes, and when the water to be measured flowing through the water sampling pipes not communicating with the measurement pipes is discharged, the blow switching valve provided in the water sampling pipe not communicating with the measurement pipe is opened.

8. The measurement method according to claim 7, wherein the linear velocity of the water to be measured flowing through the water sampling pipe is 0.6 m / sec or more.

9. A measurement method according to claim 7 or 8, wherein the blow-off switching valve is closed when the water sampling pipe is not in communication with the measurement pipe, and is opened before the water sampling pipe is in communication with the measurement pipe.

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