Water treatment system, control device, control method, and program

Abstract

This water treatment system comprises: flowmeters (200) to (208) respectively provided at a plurality of measurement points; and a control device (100) that calculates individual target values of flow rates respectively measured by the flowmeters (200) to (208), controls the flow rates at the respective measurement points so that the measured values measured by the flowmeters (200) to (208) are the respective calculated individual target values, and calculates the individual target values using a system target value, which is a target value of the entire system including the plurality of measurement points, and coefficients of the respective measurement points.

Description

Water treatment system, control device, control method and program

[0001] The present invention relates to a water treatment system, a control device, an operation control method and a program.

[0002] The quality of treated water treated and supplied by a water treatment apparatus is required to satisfy predetermined conditions. A system is disclosed that increases the circulation flow rate of treated water by controlling a valve for passing treated water to a flow path that circulates treated water into the system when the measured quality of the treated water does not satisfy the conditions (see, for example, Patent Document 1).

[0003] Japanese Unexamined Patent Application Publication No. 2008-229506

[0004] In a general water treatment system, water treatment apparatuses that perform treatment (unit operations) on water to be treated are arranged in multiple stages, or a water flow path is branched into a plurality of flow paths such as a circulation flow path and a drainage flow path. Therefore, when controlling the flow rate of treated water supplied from the system, fine flow rate control can be achieved by performing flow rate control at each point. In such cases, it is necessary to individually set target values for individual flow rates at a plurality of locations based on the target flow rate value of the entire system and input them to the system. As a result, there is a problem that this takes time and effort. Furthermore, manual setting and input may lead to human error.

[0005] An object of the present invention is to provide a water treatment system, a control device, an operation control method and a program that can easily perform fine flow rate control of the system.

[0006] The water treatment system of the present invention comprises: a plurality of flow rate measuring means provided at each of a plurality of measurement points; an individual target value calculation unit that calculates individual target values ​​for the flow rate measured by each of the plurality of flow rate measuring means; and an individual flow rate control unit that controls the flow rate at each of the plurality of measurement points so that each of the measured values ​​measured by the plurality of flow rate measuring means becomes the individual target value calculated by the individual target value calculation unit, wherein the individual target value calculation unit calculates each of the individual target values ​​using a system target value which is a target value for the entire system including the plurality of measurement points and a coefficient for each of the plurality of measurement points.

[0007] Furthermore, the control device of the present invention includes: an individual target value calculation unit that calculates individual target values ​​for the flow rate measured by each of the multiple flow rate measuring means provided at each of the multiple measurement points; a measurement value acquisition unit that acquires each of the measurement values ​​measured by the multiple flow rate measuring means; and an individual flow rate control unit that controls the flow rate at each of the multiple measurement points so that each of the measurement values ​​acquired by the measurement value acquisition unit becomes the individual target value calculated by the individual target value calculation unit. The individual target value calculation unit calculates each of the individual target values ​​using a system target value which is a target value for the entire system including the multiple measurement points and a coefficient for each of the multiple measurement points.

[0008] Furthermore, the control method of the present invention includes the following processes: calculating individual target values ​​of the flow rate measured by each of the multiple flow rate measuring means provided at each of the multiple measurement points using a system target value which is a target value for the entire system including the multiple measurement points and a coefficient for each of the multiple measurement points; acquiring each of the measured values ​​measured by the multiple flow rate measuring means; and controlling the flow rate at each of the multiple measurement points so that each of the acquired measured values ​​becomes each of the individual target values ​​calculated.

[0009] Furthermore, the program of the present invention causes a computer to perform the following steps: calculate individual target values ​​for the flow rate measured by each of the multiple flow rate measuring means provided at each of the multiple measurement points using a system target value which is a target value for the entire system including the multiple measurement points and a coefficient for each of the multiple measurement points; acquire each of the measured values ​​measured by the multiple flow rate measuring means; and control the flow rate at each of the multiple measurement points so that each of the acquired measured values ​​becomes each of the individual target values ​​calculated.

[0010] In this invention, precise flow rate control of the system can be easily performed.

[0011] This figure shows a first embodiment of the water treatment system according to the present invention. This figure shows an example of the components of the control device shown in Figure 1. This is a flowchart illustrating an example of a control method performed by the control device shown in Figure 1. This figure shows a second embodiment of the water treatment system according to the present invention. This figure shows an example of the components of the control device shown in Figure 4. This is a flowchart illustrating an example of a control method performed by the control device shown in Figure 4. This figure shows a third embodiment of the water treatment system according to the present invention. This figure shows an example of the components of the control device shown in Figure 7. This is a flowchart illustrating an example of a control method performed by the control device shown in Figure 7. This figure shows a fourth embodiment of the water treatment system according to the present invention. This figure shows an example of the components of the control device shown in Figure 10. This is a flowchart illustrating an example of a control method performed by the control device shown in Figure 10. This figure shows an example of a system to which the water treatment system of the present invention is applied.

[0012] Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment)

[0013] Figure 1 shows a first embodiment of the water treatment system according to the present invention. As shown in Figure 1, the water treatment system according to this embodiment includes a raw water tank 10, reverse osmosis membrane devices 20 and 21, an RO treatment tank 11, an electro-deionized water production device 22, an EDI treatment tank 12, and a control device 100. Pumps 300 and 301 and a flow meter 200 are provided between the raw water tank 10 and the reverse osmosis membrane device 20. A flow meter 201 and a pump 302 are provided between the reverse osmosis membrane device 20 and the reverse osmosis membrane device 21. A valve 400 and a flow meter 202 are provided in the flow path for draining concentrated water from the reverse osmosis membrane device 20. A flow meter 203 and a valve 402 are provided between the reverse osmosis membrane device 21 and the RO treatment tank 11. A valve 401 and a flow meter 204 are provided in the flow path for returning concentrated water from the reverse osmosis membrane device 21 to the raw water tank 10. A valve 403 and a flow meter 205 are provided in the flow path for circulating permeate water from the reverse osmosis membrane device 21 to the raw water tank 10. A pump 303 is provided between the RO treatment tank 11 and the electric deionized water production device 22. A flow meter 206 is provided at the outlet of the electric deionized water production device 22. A valve 404 is provided between the electric deionized water production device 22 and the EDI treatment tank 12. A valve 405 and a flow meter 207 are provided in the flow path for circulating the treated water from the electric deionized water production device 22 to the RO treatment tank 11. A pump 304 and a flow meter 208 are provided at the outlet of the EDI treatment tank 12. Pumps 300-304 and valves 400-405 are individual flow control means that control the flow rate individually. In the configuration shown in Figure 1, the reverse osmosis membrane apparatus 20, 21 and the electro-deionized water production apparatus 22 are listed as devices that perform a predetermined treatment on the raw water, but other devices may be used.

[0014] The raw water tank 10 is a tank in which the raw water to be treated is stored.

[0015] Pump 300 supplies raw water stored in raw water tank 10 to the downstream stage. The control device 100 controls the operating speed (output) of pump 300.

[0016] The flow meter 200 is a flow rate measuring means for measuring the flow rate of the water to be treated from the pump 300. The flow meter 200 can be any instrument that can measure the flow rate of the water to be treated from the pump 300.

[0017] Pump 301 supplies the water to be treated to the reverse osmosis membrane device 20. The control device 100 controls the operating speed (output) of pump 301.

[0018] The reverse osmosis membrane apparatus 20 is the first stage reverse osmosis membrane apparatus (RO). The reverse osmosis membrane apparatus 20 applies pressure to the water to be treated supplied by the pump 301, causing it to pass through the reverse permeate membrane and separating the water to be treated into permeate and concentrated water. The separated permeate is output to the treated water line where the pump 302 is installed. Meanwhile, the separated concentrated water is drained to the drainage line where the valve 400 is installed.

[0019] The flow meter 201 is a flow rate measuring means for measuring the flow rate of permeate from the reverse osmosis membrane device 20. The flow meter 201 can be any instrument that can measure the flow rate of permeate from the reverse osmosis membrane device 20.

[0020] The valve 400 adjusts the flow rate of concentrated water from the reverse osmosis membrane device 20 by adjusting its opening degree. The control device 100 controls the opening degree of the valve 400.

[0021] The flow meter 202 is a flow rate measuring means for measuring the flow rate of concentrated water from the reverse osmosis membrane device 20, whose flow rate is adjusted by the valve 400. The flow meter 202 can be any instrument that can measure the flow rate of concentrated water from the reverse osmosis membrane device 20, whose flow rate is adjusted by the valve 400.

[0022] Pump 302 supplies permeate from reverse osmosis membrane device 20 to reverse osmosis membrane device 21. The control device 100 controls the operating speed (output) of pump 302.

[0023] The reverse osmosis membrane apparatus 21 is a second-stage reverse osmosis (RO) membrane apparatus. The reverse osmosis membrane apparatus 21 applies pressure to the water to be treated supplied by the pump 302, causing it to pass through a reverse permeate membrane, separating the water into permeate and concentrated water. The separated permeate is output to the treated water line, which is equipped with valves 402 and 403. Meanwhile, the separated concentrated water is passed through the circulation line, which is equipped with valve 401.

[0024] The flow meter 203 is a flow rate measuring means for measuring the flow rate of permeate from the reverse osmosis membrane device 21. Any instrument capable of measuring the flow rate of permeate from the reverse osmosis membrane device 21 can be used as the flow meter 203.

[0025] Valve 401 adjusts the flow rate of concentrated water from the reverse osmosis membrane device 21 to the raw water tank 10 by adjusting its opening degree. The control device 100 controls the opening degree of valve 401.

[0026] The flow meter 204 is a flow rate measuring means for measuring the flow rate of concentrated water from the reverse osmosis membrane device 21, whose flow rate is adjusted by the valve 401. The flow meter 204 can be any instrument that can measure the flow rate of concentrated water from the reverse osmosis membrane device 21, whose flow rate is adjusted by the valve 401.

[0027] The valve 402 adjusts the flow rate of permeate from the reverse osmosis membrane device 21 to the RO treatment tank 11 by adjusting its opening degree. The control device 100 controls the opening degree of the valve 402.

[0028] The valve 403 adjusts the flow rate of permeate from the reverse osmosis membrane device 21 to the raw water tank 10 by adjusting its opening degree. The control device 100 controls the opening degree of the valve 403.

[0029] The flow meter 205 is a flow rate measuring means for measuring the flow rate of permeate from the reverse osmosis membrane device 21, whose flow rate is adjusted by the valve 403, to the raw water tank 10. The flow meter 205 can be any instrument that can measure the flow rate of permeate from the reverse osmosis membrane device 21, whose flow rate is adjusted by the valve 403, to the raw water tank 10.

[0030] The RO treatment tank 11 is a tank that stores permeate from the reverse osmosis membrane device 21, whose flow rate is adjusted by the valve 402. The RO treatment tank 11 also serves as a raw water tank for storing the water to be treated by the electro-deionized water production device 22 located downstream.

[0031] Pump 303 supplies treated water (water to be treated) stored in RO treatment tank 11 to electric deionized water production device 22. The control device 100 controls the operating speed (output) of pump 303.

[0032] The electric deionized water production device 22 is equipped with a positive electrode and a negative electrode. By passing an electric current between the positive electrode and the negative electrode in the electric deionized water production device 22, the electric deionized water production device 22 produces desalinated water and concentrated water from the supplied raw water.

[0033] The flow meter 206 is a flow rate measuring means for measuring the flow rate of demineralized water from the electric deionized water production device 22. The flow meter 206 can be any instrument that can measure the flow rate of demineralized water from the electric deionized water production device 22.

[0034] The valve 404 adjusts the flow rate of desalinated water from the electric deionized water production device 22 to the EDI treatment tank 12 by adjusting its opening degree. The control device 100 controls the opening degree of the valve 404.

[0035] Valve 405 adjusts the flow rate of demineralized water from the electric deionized water production device 22 to the RO treatment tank 11 by adjusting its opening degree. The control device 100 controls the opening degree of valve 405.

[0036] The flow meter 207 is a flow rate measuring means for measuring the flow rate of demineralized water from the electric deionized water production device 22, whose flow rate is adjusted by the valve 405, to the RO treatment tank 11. The flow meter 207 can be any instrument that can measure the flow rate of demineralized water from the electric deionized water production device 22, whose flow rate is adjusted by the valve 405, to the RO treatment tank 11.

[0037] The EDI treatment tank 12 is a tank that stores desalinated water from the electro-deionized water production device 22, whose flow rate is adjusted by a valve 404.

[0038] The pump 304 supplies treated water (desalted water) stored in the EDI treated water tank 12 to a supply destination. The control device 100 controls the operating rotation speed (output) of the pump 304.

[0039] The flowmeter 208 is a flow rate measuring means that measures the flow rate of treated water from the pump 304. The flowmeter 208 may be any instrument as long as it can measure the flow rate of treated water from the pump 304.

[0040] The control device 100 controls the outputs of the pumps 300 to 304 and the opening degrees of the valves 400 to 405 based on the flow rates measured by the flowmeters 200 to 208 respectively provided at a plurality of measurement points. FIG. 2 is a diagram showing an example of components included in the control device 100 shown in FIG. 1. As shown in FIG. 2, the control device 100 shown in FIG. 1 includes an individual target value calculation unit 110, a measured value acquisition unit 120, and an individual flow rate control unit 130. Note that FIG. 2 only shows main components related to the present embodiment among the components included in the control device 100 shown in FIG. 1.

[0041] The individual target value calculation unit 110 calculates individual target values for the flow rates respectively measured by the flowmeters 200 to 208. The individual target value calculation unit 110 calculates each individual target value, which is an individual target, by using a system target value that is a preset target flow rate of the system and coefficients for each of the plurality of measurement points where the flowmeters 200 to 208 are respectively arranged. Specifically, for example, the individual target value calculation unit 110 calculates each individual target value by multiplying the system target value by the coefficient of each of the plurality of measurement points. Note that, when calculating each individual target value, the individual target value calculation unit 110 may calculate each individual target value using not only such multiplication but also addition, subtraction, division, or any combination thereof.

[0042] This coefficient is determined based on the water balance in the water treatment system, the performance of each arranged water treatment device, the required water quality and water volume, and the configured trains. For example, if it is known that scaling does not occur when the recovery rate is 80% with respect to an assumed amount of treated water, the coefficient may be set to "0.8". The system target value is 100 (m3 If the coefficient at the measurement point of flowmeter 203 is "0.8" and the coefficient at the measurement point of flowmeter 204 is "0.2", then the individual target value calculation unit 110 calculates the individual target value at the measurement point of flowmeter 203 as 100 × 0.8 = 80 (m 3 The calculation is performed as follows: ( / h), and the individual target value at the measurement point of the flow meter 204 is set to 100 × 0.2 = 20 (m 3 The calculation is performed as follows: ( / h). After that, the system target value is 120m 3 If changed to / h, the individual target value calculation unit 110 calculates the individual target value at the measurement point of the flow meter 203 as 120 × 0.8 = 96 (m 3 The calculation is performed as follows: ( / h), and the individual target value at the measurement point of the flow meter 204 is 120 × 0.2 = 24 (m 3 It is calculated as ( / h).

[0043] Furthermore, this coefficient may be set specifically for the system. Also, this coefficient may be a value that can be changed according to the operating conditions of the system (water quality, flow rate, power consumption, etc.). For example, if it is determined that the risk of scaling has increased based on the water quality of the treated water from the reverse osmosis membrane device 21, the coefficient of the measurement point of the flow meter 204 may be lowered in order to reduce the opening of the valve 401 and lower the recovery rate (making it less likely for scale to form). Also, if the amount and quality of treated water supplied from the system are stable (the fluctuation range is within a predetermined range), the coefficients of each measurement point on the circulation line and each measurement point on the supply line may be lowered to achieve energy-saving operation. Also, if it is determined that the water quality has deteriorated based on the water quality of the treated water from the electric deionized water production device 22, the coefficient of the measurement point of the flow meter 206 may be lowered and the output of the pump 303 may be lowered in order to improve the water quality. This makes it possible to increase the current applied per unit flow rate in the electric deionized water production device 22. By making the coefficients changeable, it becomes easier to understand the system target value and its distribution status through the changed coefficients, even if the coefficients are altered.

[0044] The individual target value calculation unit 110 notifies the individual flow control unit 130 of each of the individual target values ​​it has calculated.

[0045] The measured value acquiring unit 120 acquires measured values (flow rate values) measured by each of flowmeters 200 to 208 from each of the flowmeters 200 to 208. There is no particular limitation on the timing at which the measured value acquiring unit 120 acquires the measured values (flow rate values), but in consideration of the individual flow rate control unit 130 performing control in accordance with the measured values (flow rate values), shorter acquisition time intervals are preferable. The measured value acquiring unit 120 notifies the acquired measured values (flow rate values) to the individual flow rate control unit 130.

[0046] The individual flow rate control unit 130 controls the outputs of pumps 300 to 304 and the opening degrees of valves 400 to 405 such that each of the measured values notified from the measured value acquiring unit 120 matches each of the individual target values notified from the individual target value calculating unit 110. For example, when the measured value measured by the flowmeter 200 is lower than the individual target value, the individual flow rate control unit 130 increases the output of the pump 300. When the measured value measured by the flowmeter 200 is higher than the individual target value, the individual flow rate control unit 130 reduces the output of the pump 300. When the measured value measured by the flowmeter 202 is lower than the individual target value, the individual flow rate control unit 130 increases the opening degree of the valve 400. When the measured value measured by the flowmeter 202 is higher than the individual target value, the individual flow rate control unit 130 reduces the opening degree of the valve 400. With the individual flow rate control unit 130 controlling the outputs of the pumps 300 to 304 and the opening degrees of the valves 400 to 405 in this manner, each of the measured values notified from the measured value acquiring unit 120 gradually approaches each of the individual target values notified from the individual target value calculating unit 110. When the individual flow rate control unit 130 controls the outputs of the pumps 300 to 304, it may output a control signal to an inverter that controls the rotation speed of each of the pumps 300 to 304.

[0047] Furthermore, in the case of a system in which multiple series are arranged in parallel, a valve may be provided at the inlet of each series, and the individual flow control unit 130 may increase or decrease the number of operating series by controlling the opening and closing of the valve based on the relationship between the measured value and the individual target value measured at the branching point where the treated water branches into multiple series. In this case, if the measured value exceeds the individual target value and the difference between the measured value and the individual target value exceeds a predetermined range, the valve is opened and the number of operating series is increased. On the other hand, if the measured value falls below the individual target value and the difference between the measured value and the individual target value exceeds a predetermined range, some valves are closed and the number of operating series is decreased. This increase or decrease in the number of series may be done using valve opening and closing control, or by an operator (installation and removal of series).

[0048] The following describes the specific control performed by the individual flow control unit 130 in the configuration shown in Figure 1. The individual flow control unit 130 controls the output of the pump 300 so that the flow rate measured by the flow meter 200, acquired by the measurement value acquisition unit 120, becomes the flow rate calculated by the individual target value calculation unit 110 using a coefficient at the measurement point of the flow meter 200. The individual flow control unit 130 also controls the output of the pump 301 so that the flow rate measured by the flow meter 201, acquired by the measurement value acquisition unit 120, becomes the flow rate calculated by the individual target value calculation unit 110 using a coefficient at the measurement point of the flow meter 201. Furthermore, the individual flow control unit 130 controls the opening degree of the valve 400 so that the flow rate measured by the flow meter 202, acquired by the measurement value acquisition unit 120, becomes the flow rate calculated by the individual target value calculation unit 110 using a coefficient at the measurement point of the flow meter 202. Furthermore, the individual flow control unit 130 controls the output of the pump 302 so that the flow rate measured by the flow meter 203, acquired by the measurement value acquisition unit 120, becomes the flow rate calculated by the individual target value calculation unit 110 using a coefficient at the measurement point of the flow meter 203. Furthermore, the individual flow control unit 130 controls the opening degree of the valve 401 so that the flow rate measured by the flow meter 204, acquired by the measurement value acquisition unit 120, becomes the flow rate calculated by the individual target value calculation unit 110 using a coefficient at the measurement point of the flow meter 204. Furthermore, the individual flow control unit 130 controls the opening degree of the valve 403 so that the flow rate measured by the flow meter 205, acquired by the measurement value acquisition unit 120, becomes the flow rate calculated by the individual target value calculation unit 110 using a coefficient at the measurement point of the flow meter 205. Furthermore, the individual flow control unit 130 controls the output of the pump 303 so that the flow rate measured by the flow meter 206, acquired by the measurement value acquisition unit 120, becomes the flow rate calculated by the individual target value calculation unit 110 using a coefficient at the measurement point of the flow meter 206. Also, the individual flow control unit 130 controls the opening degree of the valve 405 so that the flow rate measured by the flow meter 207, acquired by the measurement value acquisition unit 120, becomes the water level calculated by the individual target value calculation unit 110 using a coefficient at the measurement point of the flow meter 207. Furthermore, the individual flow control unit 130 controls the opening degree of the valve 404 and the output of the pump 304 so that the flow rate measured by the flow meter 208, acquired by the measurement value acquisition unit 120, becomes the water level calculated by the individual target value calculation unit 110 using a coefficient at the measurement point of the flow meter 208.

[0049] The control method for the control device 100 shown in Figure 1 will be described below. Figure 3 is a flowchart illustrating an example of the control method for the control device 100 shown in Figure 1.

[0050] The individual target value calculation unit 110 calculates individual target values ​​for the flow rates measured by each of the flow meters 200 to 208 based on the system target value and coefficients at each measurement point (step S1). The measurement value acquisition unit 120 acquires the measurement values ​​measured by each of the flow meters 200 to 208 from each of the flow meters 200 to 208 (step S2). The processes of step S1 and step S2 may be performed in either order or simultaneously. Then, the individual flow rate control unit 130 controls the flow rate by controlling the output of the pumps 300 to 304 and the opening of the valves 400 to 405 so that each measurement value acquired by the measurement value acquisition unit 120 matches the individual target value calculated by the individual target value calculation unit 110 (step S3).

[0051] Generally, when changing the flow rate of a system, a target flow rate is individually set at each point within the system based on the changed value. Then, the flow rate at each point is individually adjusted using flow control means such as pumps and valves so that it reaches the set target value. As a result, flow rate adjustment is time-consuming, and water quality fluctuations may occur before the adjustment can be made. Furthermore, it is not possible to handle cases where the system target value is changed in real time, as in the second to fourth embodiments. In addition, there are cases where the flow rate at each point is individually controlled using flow control means such as pumps and valves based on the water level in a tank provided in the system. In this case, there is a risk that the flow rate ratio between each point will fluctuate if each point is controlled individually.

[0052] Therefore, in this embodiment, coefficients are set in advance for each of the multiple measurement points in the system, and the individual flow rate control means controls the flow rate at each measurement point individually so that the measured value at that measurement point approaches the individual target value calculated using the system's target value and the coefficient. This eliminates the need for manual input of each individual flow rate target value, making it easy to perform fine-tuned flow rate control of the system. The speed at which the individual flow rate control unit 130 controls the output of pumps 300 to 304 and the opening of valves 400 to 405 is not specifically defined. For example, the speed at which the individual flow rate control unit 130 controls the output of pump 301 so that the flow rate measured by flow meter 201 approaches the individual flow rate value calculated by the individual target value calculation unit 110 is faster than the speed at which the individual flow rate control unit 130 controls the output of pump 303 so that the flow rate measured by flow meter 206 approaches the individual flow rate value calculated by the individual target value calculation unit 110. The same applies to the timing of the start of control. This is because the effects on the water quality fluctuations of the treated water when the flow rate is changed by the unit operation performed by the reverse osmosis membrane device 20 and the electro-deionized water production device 22 are different from those of the other. In addition, control may be performed using other measured values ​​that are linked to the flow rate (for example, the water pressure value measured by the pressure gauge, the rate of increase or decrease of the water level of the treated water stored in the tank, the opening degree of the valve, etc.) in addition to the flow rate value measured by the flow meter. (Second Embodiment)

[0053] Figure 4 shows a second embodiment of the water treatment system according to the present invention. As shown in Figure 4, the water treatment system according to this embodiment has a control device 101 instead of the control device 100 in the embodiment shown in Figure 1. In addition to the functions of the control device 100 in the first embodiment, the control device 101 has a function to calculate a system target value according to the demand for treated water. Figure 5 shows an example of the components of the control device 101 shown in Figure 4. As shown in Figure 5, the control device 101 shown in Figure 4 has an individual target value calculation unit 111, a measurement value acquisition unit 120, an individual flow rate control unit 130, a demand flow rate value acquisition unit 141, and a system target value calculation unit 151. The measurement value acquisition unit 120 and the individual flow rate control unit 130 are the same as those in the first embodiment. Note that Figure 5 shows only the main components related to this embodiment among the components of the control device 101 shown in Figure 4.

[0054] The demand flow rate acquisition unit 141 acquires a flow rate value indicating the flow rate of treated water supplied from the water treatment system. In the configuration shown in Figure 4, the demand flow rate acquisition unit 141 acquires the flow rate value measured by the flow meter 208. The demand flow rate acquisition unit 141 notifies the system target value calculation unit 151 of the acquired flow rate value.

[0055] The system target value calculation unit 151 calculates the system target value based on the flow rate value notified by the demand flow rate value acquisition unit 141. For example, if the flow rate value measured by the flow meter 208 notified by the demand flow rate value acquisition unit 141 is 100 (t / h), the system target value calculation unit 151 calculates 105 (t / h) as the system target value by adding 5% to 100 (t / h). The system target value calculation unit 151 notifies the individual target value calculation unit 111 of the calculated system target value.

[0056] The individual target value calculation unit 111 calculates individual target values, which are individual targets, using the system target value notified by the system target value calculation unit 151 and the coefficients of each of the multiple measurement points where the flow meters 200 to 208 are located. The coefficients and calculation methods are the same as those in the first embodiment. For example, if the system target value calculated by the system target value calculation unit 151 is 105 (t / h), and the coefficient for the measurement point of flow meter 201 is set to "1.5" and the coefficient for the measurement point of flow meter 203 is set to "1.2", the individual target value calculation unit 111 calculates the individual target value for the flow rate measured by flow meter 201 as 105 × 1.5 = 157.5 (t / h) and the individual target value for the flow rate measured by flow meter 203 as 105 × 1.2 = 126 (t / h). The individual target value calculation unit 110 notifies the individual flow control unit 130 of each of the calculated individual target values.

[0057] The control method for the control device 101 shown in Figure 4 will be described below. Figure 6 is a flowchart illustrating an example of the control method for the control device 101 shown in Figure 4.

[0058] The demand flow rate value acquisition unit 141 acquires a flow rate value indicating the flow rate of treated water supplied from the water treatment system (step S11). Next, the system target value calculation unit 151 calculates a system target value based on the flow rate value acquired by the demand flow rate value acquisition unit 141 (step S12). Then, the individual target value calculation unit 111 calculates individual target values ​​for the flow rates measured by each of the flow meters 200 to 208 based on the system target value calculated by the system target value calculation unit 151 and coefficients at each measurement point (step S13).

[0059] Furthermore, the measurement value acquisition unit 120 acquires the measurement values ​​measured by each of the flow meters 200 to 208 from each of the flow meters 200 to 208 (step S14). Then, the individual flow control unit 130 controls the flow rate by controlling the output of the pumps 300 to 304 and the opening of the valves 400 to 405 so that each measurement value acquired by the measurement value acquisition unit 120 becomes each of the individual target values ​​calculated by the individual target value calculation unit 111 (step S15).

[0060] Thus, in this embodiment, in addition to the first embodiment, the necessary system target value is calculated according to the flow rate of treated water supplied by the system. Therefore, real-time individual flow rate control according to the operating conditions can be performed. (Third Embodiment)

[0061] Figure 7 shows a third embodiment of the water treatment system according to the present invention. As shown in Figure 7, the water treatment system according to this embodiment has a control device 102 instead of the control device 100 in the embodiment shown in Figure 1. In addition, water level gauges 500 and 501 are provided in the RO treatment tank 11 and the EDI treatment tank 12, respectively.

[0062] The water level gauge 500 is a water level measuring means for measuring the water level of the treated water stored in the RO treatment tank 11. The water level gauge 500 can be any instrument that can measure the water level of the treated water stored in the RO treatment tank 11. The water level gauge 501 is a water level measuring means for measuring the water level of the treated water stored in the EDI treatment tank 12. The water level gauge 501 can be any instrument that can measure the water level of the treated water stored in the EDI treatment tank 12.

[0063] In addition to the functions of the control device 100 in the first embodiment, the control device 102 also has a function to calculate a system target value according to the water level of the treated water stored in the treated water tank. Figure 8 is a diagram showing an example of the components of the control device 102 shown in Figure 7. As shown in Figure 8, the control device 102 shown in Figure 7 has an individual target value calculation unit 112, a measurement value acquisition unit 120, an individual flow rate control unit 130, a system target value calculation unit 152, and a water level value acquisition unit 162. The measurement value acquisition unit 120 and the individual flow rate control unit 130 are the same as those in the first embodiment. Note that Figure 8 shows only the main components of the control device 102 shown in Figure 7 that are relevant to this embodiment.

[0064] The water level acquisition unit 162 acquires a water level value indicating the water level of the treated water stored in the treatment tank. In the configuration shown in Figure 7, the water level acquisition unit 162 acquires the water level value measured by the water level gauge 501. The water level acquisition unit 162 notifies the system target value calculation unit 152 of the acquired water level value. Alternatively, the water level acquisition unit 162 may acquire the water level value measured by the water level gauge 500 and notify the system target value calculation unit 152 of the acquired water level value.

[0065] The system target value calculation unit 152 calculates the system target value of the flow rate based on the water level value notified by the water level acquisition unit 162. The system target value calculation unit 152 may also calculate the system target value using a predetermined algorithm. In this case, for example, if the water level value notified by the water level acquisition unit 162 is lower than a preset reference value, the system target value calculation unit 152 calculates a higher value as the system target value of the flow rate. Also, if the water level value notified by the water level acquisition unit 162 is higher than a preset reference value, the system target value calculation unit 152 calculates a lower value as the system target value of the flow rate. The system target value calculation unit 152 may also pre-associate the water level value with the target value and calculate the target value associated with the water level value notified by the water level acquisition unit 162 as the system target value. This association may be on a straight line represented by a linear function in which the target value decreases as the water level value increases. Alternatively, this association may be such that the target value decreases curvilinearly as the water level value increases. Furthermore, this correspondence may be such that the target value decreases in stages as the water level increases. The system target value calculation unit 152 may also calculate the system target value based on the rate of change of the water level notified by the water level acquisition unit 162, and the magnitude of the difference between the water level notified by the water level acquisition unit 162 and the reference value. In this case, the faster the rate of increase of the water level notified by the water level acquisition unit 162, the smaller the system target value calculated by the system target value calculation unit 152 may be. Also, the greater the water level notified by the water level acquisition unit 162 is greater than the reference value, the smaller the system target value calculated by the system target value calculation unit 152 may be. The system target value calculation unit 152 notifies the individual target value calculation unit 112 of the calculated system target value.

[0066] The individual target value calculation unit 112 calculates individual target values, which are individual targets, using the system target value notified by the system target value calculation unit 152 and the coefficients for each of the multiple measurement points where the flow meters 200 to 208 are located. The coefficients and calculation methods are the same as those in the first embodiment.

[0067] The control method for the control device 102 shown in Figure 7 will be described below. Figure 9 is a flowchart illustrating an example of the control method for the control device 102 shown in Figure 7.

[0068] The water level acquisition unit 162 acquires the water level value indicating the water level measured by the water level gauge 501 (Step S21). Next, the system target value calculation unit 152 calculates the system target value of the flow rate based on the water level value acquired by the water level acquisition unit 162 (Step S22). Then, the individual target value calculation unit 112 calculates the individual target values ​​of the flow rates measured by each of the flow meters 200 to 208 based on the system target value calculated by the system target value calculation unit 152 and the coefficients at each measurement point (Step S23).

[0069] Furthermore, the measurement value acquisition unit 120 acquires the measurement values ​​measured by each of the flow meters 200 to 208 from each of the flow meters 200 to 208 (step S24). Then, the individual flow control unit 130 controls the flow rate by controlling the output of the pumps 300 to 304 and the opening of the valves 400 to 405 so that each measurement value acquired by the measurement value acquisition unit 120 becomes each of the individual target values ​​calculated by the individual target value calculation unit 112 (step S25).

[0070] Thus, in this embodiment, in addition to the first embodiment, the necessary system target value is calculated according to the water level in the tank supplied by the system. Therefore, real-time individual flow rate control can be performed in accordance with the balance between the supply and demand of the treated water generated by the system. (Fourth Embodiment)

[0071] Figure 10 shows a fourth embodiment of the water treatment system according to the present invention. As shown in Figure 10, the water treatment system according to this embodiment has a control device 103 instead of the control device 100 in the embodiment shown in Figure 1. In addition, a water quality meter 600 is provided in the flow path that supplies raw water to the raw water tank 10.

[0072] The water quality meter 600 is a water quality measuring device for measuring the water quality of the raw water stored in the raw water tank 10. The water quality meter 600 can be any instrument that can measure the water quality of the raw water stored in the raw water tank 10. The water quality meter 600 may also be a concentration meter that measures the concentration of impurities contained in the raw water. For example, the water quality meter 600 measures the TOC (Total Organic Carbon), turbidity (SS), ion concentration, silica concentration, etc. of the raw water stored in the raw water tank 10 as water quality values.

[0073] In addition to the functions of the control device 100 in the first embodiment, the control device 103 has a function to calculate a system target value based on at least one of the water quality and flow rate of the raw water (water to be treated) supplied to the water treatment system. Figure 11 is a diagram showing an example of the components of the control device 103 shown in Figure 10. As shown in Figure 11, the control device 103 shown in Figure 10 has an individual target value calculation unit 113, a measurement value acquisition unit 120, an individual flow rate control unit 130, a system target value calculation unit 153, and a raw water information acquisition unit 173. The measurement value acquisition unit 120 and the individual flow rate control unit 130 are the same as those in the first embodiment. Note that Figure 11 shows only the main components related to this embodiment from the components of the control device 103 shown in Figure 10.

[0074] The raw water information acquisition unit 173 acquires water quality values ​​indicating the water quality of the raw water (water to be treated) supplied to the water treatment system. In the configuration shown in Figure 10, the raw water information acquisition unit 173 acquires the water quality values ​​measured by the water quality meter 600. The water level value acquisition unit 162 notifies the system target value calculation unit 153 of the acquired water quality values.

[0075] The system target value calculation unit 153 calculates the system target value of the flow rate based on the water quality values ​​notified by the raw water information acquisition unit 173. The system target value calculation unit 153 may also calculate the system target value using a predetermined algorithm. In this case, for example, if the water quality values ​​notified by the raw water information acquisition unit 173 are higher (worse) than a pre-set standard value, the system target value calculation unit 153 calculates a lower value as the system target value of the flow rate. Also, if the water quality values ​​notified by the raw water information acquisition unit 173 are lower (better) than a pre-set standard value, the system target value calculation unit 153 calculates a higher value as the system target value of the flow rate. The system target value calculation unit 153 may also pre-associate water quality values ​​with target values ​​and calculate the target value associated with the water quality values ​​notified by the raw water information acquisition unit 173 as the system target value. This association may be on a straight line represented by a linear function where the target value decreases as the water quality value deteriorates. Alternatively, this association may be on a curve where the target value decreases as the water quality value deteriorates. Furthermore, this correspondence may be such that the target value decreases in stages as the water quality value deteriorates. The system target value calculation unit 153 may also calculate the system target value based on the rate of change in the water quality value notified by the raw water information acquisition unit 173, and the magnitude of the difference between the water quality value notified by the raw water information acquisition unit 173 and the standard value. In this case, the system target value calculation unit 153 may calculate a smaller system target value the faster the rate of deterioration of the water quality value notified by the raw water information acquisition unit 173. Also, the system target value calculation unit 153 may calculate a smaller system target value the worse the water quality value notified by the raw water information acquisition unit 173 is than the standard value, and the larger the difference between the water quality value and the standard value. The system target value calculation unit 153 notifies the individual target value calculation unit 113 of the calculated system target value.

[0076] The individual target value calculation unit 113 calculates individual target values, which are individual targets, using the system target value notified by the system target value calculation unit 153 and the coefficients for each of the multiple measurement points where the flow meters 200 to 208 are located. The coefficients and calculation methods are the same as those in the first embodiment.

[0077] The control method for the control device 103 shown in Figure 10 will be described below. Figure 12 is a flowchart illustrating an example of the control method for the control device 103 shown in Figure 10.

[0078] The raw water information acquisition unit 173 acquires water quality values ​​indicating the water quality measured by the water quality meter 600 (Step S31). Next, the system target value calculation unit 153 calculates the system target value of the flow rate based on the water quality values ​​acquired by the raw water information acquisition unit 173 (Step S32). Then, the individual target value calculation unit 113 calculates the individual target values ​​of the flow rates measured by each of the flow meters 200 to 208 based on the system target value calculated by the system target value calculation unit 153 and the coefficients at each measurement point (Step S33).

[0079] Furthermore, the measurement value acquisition unit 120 acquires the measurement values ​​measured by each of the flow meters 200 to 208 from each of the flow meters 200 to 208 (step S34). Then, the individual flow control unit 130 controls the flow rate by controlling the output of the pumps 300 to 304 and the opening of the valves 400 to 405 so that each measurement value acquired by the measurement value acquisition unit 120 becomes each of the individual target values ​​calculated by the individual target value calculation unit 113 (step S35).

[0080] Thus, in this embodiment, in addition to the first embodiment, the necessary system target values ​​are calculated according to the water quality of the raw water supplied to the system. Therefore, real-time individual flow rate control can be performed in response to load fluctuations of the system due to fluctuations in the water quality of the raw water.

[0081] Furthermore, system target values ​​may be set based on the operational performance (hereinafter referred to as "operational performance") of this system, the plants to which this system is applied, and the recipients of treated water supplied from this system. In this case, a learning model may be trained to predict the demand for treated water based on operational performance for each operating time period, day of the week, and season, and the system target values ​​may be set using the demand forecast for treated water output from the learning model by inputting the operating time period, day of the week, and season into the learning model.

[0082] Figure 13 shows an example of a system to which the water treatment system of the present invention is applied. The system shown in Figure 13 has a pretreatment system 30, a primary pure water production system 40, and a secondary pure water production system 50, which is a so-called subsystem. The pretreatment system 30 may be a system used in a general water treatment system. The pretreatment system 30 is a water treatment facility that removes fine particles from the supplied raw water. The primary pure water production system 40 performs predetermined treatment on the treated water treated in the pretreatment system 30 and supplies the treated water to the secondary pure water production system 50. The secondary pure water production system 50 may be a secondary pure water production system used in a general water treatment system. The secondary pure water production system 50 removes trace amounts of ions and total organic carbon that could not be removed by the primary pure water production system 40. The treated water treated in the secondary pure water production system 50 is supplied to the use point, which is the destination of the treated water.

[0083] The water treatment system of the present invention is applied to the primary pure water production system 40 shown in Figure 13. For example, the raw water tank 10 shown in Figures 1, 4, 7, and 10 may be applied to the desalination tank 41 in the primary pure water production system 40 shown in Figure 13, the reverse osmosis membrane devices 20 and 21 shown in Figures 1, 4, 7, and 10 may be applied to the reverse osmosis membrane device 42 shown in Figure 13, and the RO treatment tank 11 shown in Figures 1, 4, 7, and 10 may be applied to the RO permeate tank 43 shown in Figure 13. Alternatively, the electric deionized water production device 22 shown in Figures 1, 4, 7, and 10 may be applied to the EDI 44 shown in Figure 13, and the EDI treatment tank 12 shown in Figures 1, 4, 7, and 10 may be applied to the EDI treatment tank 45 shown in Figure 13. Furthermore, these may be applied in any combination. For example, the desalination tank 41, reverse osmosis membrane device 42, RO permeation tank 43, EDI 44, and EDI treatment tank 45 shown in Figure 13 may be treated as a single device group, and individual target values ​​calculated according to the present invention may be set for this device group. Alternatively, the desalination tank 41, reverse osmosis membrane device 42, RO permeation tank 43, EDI 44, EDI treatment tank 45, UV oxidation device 46, and ultrapure water tank 51 shown in Figure 13 may be treated as a single device group, and individual target values ​​calculated according to the present invention may be set for this device group.

[0084] Alternatively, the amount of ultrapure water supplied to the use point 60 shown in Figure 13 may be the same as the supply amount of the system described in the second embodiment. In this case, based on the amount of ultrapure water supplied to the use point 60, the target flow rate value for each device may be calculated using the coefficients of each device constituting the primary pure water production system 40.

[0085] The above explanation describes how each component is assigned a specific function (process), but this assignment is not limited to those described above. Furthermore, the configurations of the components described above are merely examples and are not limited to them. Also, the embodiments described above may be combined in any combination.

[0086] The processing performed by each of the control devices 100 to 103 described above may be carried out by logic circuits created according to their respective purposes. Alternatively, a computer program (hereinafter referred to as "program") describing the processing content as a procedure may be recorded on a recording medium readable by each of the control devices 100 to 103, and the program recorded on this recording medium may be read and executed by each of the control devices 100 to 103. The recording media readable by each of the control devices 100 to 103 include portable recording media such as floppy disks, magneto-optical disks, DVDs (Digital Versatile Discs), CDs (Compact Discs), Blu-ray Discs, USB (Universal Serial Bus) memory, and SD cards, as well as built-in memory such as ROM (Read Only Memory) and RAM (Random Access Memory), and HDDs (Hard Disk Drives) in each of the control devices 100 to 103. Programs recorded on these recording media are read by the CPU (not shown) provided in each of the control devices 100 to 103, and the same processing as described above is performed under the control of the CPU. In this context, the CPU acts as a computer that executes programs read from a recording medium on which those programs are stored.

[0087] This application claims priority based on Japanese Patent Application No. 2025-051006, filed on 26 March 2025, and incorporates all of its disclosures herein.

[0088] 10 Raw water tank 11 RO treatment tank 12 EDI treatment tank 20, 21, 42 Reverse osmosis membrane device 22 Electric deionized water production device 30 Pretreatment system 40 Primary pure water production system 41 Desalination tank 43 RO permeate tank 44 EDI 45 EDI treatment tank 46 UV oxidation device 50 Secondary pure water production system 51 Ultrapure water tank 60 Use point 100-103 Control device 110-113 Individual target value calculation unit 120 Measurement value acquisition unit 130 Individual flow control unit 141 Demand flow rate acquisition unit 151-153 System target value calculation unit 162 Water level value acquisition unit 173 Raw water information acquisition unit 200-208 Flow meter 300-304 Pump 400-405 Valve 500,501 Water level gauge 600 Water quality meter

Claims

1. A water treatment system comprising: a plurality of flow rate measuring means provided at each of a plurality of measurement points; an individual target value calculation unit that calculates individual target values ​​for the flow rates measured by each of the plurality of flow rate measuring means; and an individual flow rate control unit that controls the flow rate at each of the plurality of measurement points so that each of the measured values ​​measured by the plurality of flow rate measuring means becomes the individual target value calculated by the individual target value calculation unit, wherein the individual target value calculation unit calculates each of the individual target values ​​using a system target value which is a target value for the entire system including the plurality of measurement points and a coefficient for each of the plurality of measurement points.

2. A water treatment system according to claim 1, comprising a system target value calculation unit for calculating the system target value, wherein the individual target value calculation unit calculates each of the individual target values ​​by multiplying the system target value calculated by the system target value calculation unit by the coefficient of each of the plurality of measurement points.

3. A water treatment system according to claim 2, wherein the system target value calculation unit calculates the system target value based on the flow rate of treated water supplied from the water treatment system.

4. A water treatment system according to claim 2, comprising: a tank for storing treated water supplied from the water treatment system and supplying the stored treated water to a recipient upon request; and a water level measuring means for measuring the water level of the treated water stored in the tank, wherein the system target value calculation unit calculates the system target value based on the water level measured by the water level measuring means.

5. A water treatment system according to claim 2, comprising a water quality measuring means for measuring the water quality of water to be treated supplied to the water treatment system, wherein the system target value calculation unit calculates the system target value based on the water quality measured by the water quality measuring means.

6. A water treatment system according to any one of claims 1 to 5, wherein the individual flow control unit controls the output of a pump or the opening or closing of a valve provided in the flow path.

7. A control device comprising: an individual target value calculation unit that calculates individual target values ​​for the flow rate measured by each of a plurality of flow rate measuring means provided at each of a plurality of measurement points; a measurement value acquisition unit that acquires each of the measurement values ​​measured by the plurality of flow rate measuring means; and an individual flow rate control unit that controls the flow rate at each of the plurality of measurement points so that each of the measurement values ​​acquired by the measurement value acquisition unit becomes the individual target value calculated by the individual target value calculation unit, wherein the individual target value calculation unit calculates each of the individual target values ​​using a system target value which is a target value for the entire system including the plurality of measurement points and a coefficient for each of the plurality of measurement points.

8. A control method comprising: a process of calculating individual target values ​​for the flow rate measured by each of the multiple flow rate measuring means provided at each of the multiple measurement points, using a system target value which is a target value for the entire system including the multiple measurement points and a coefficient for each of the multiple measurement points; a process of acquiring each of the measured values ​​measured by the multiple flow rate measuring means; and a process of controlling the flow rate at each of the multiple measurement points so that each of the acquired measured values ​​becomes each of the individual target values ​​calculated.

9. A program for causing a computer to execute the following steps: a procedure for calculating individual target values ​​of the flow rate measured by each of the multiple flow rate measuring means provided at each of the multiple measurement points, using a system target value which is a target value for the entire system including the multiple measurement points and a coefficient for each of the multiple measurement points; a procedure for acquiring each of the measured values ​​taken by the multiple flow rate measuring means; and a procedure for controlling the flow rate at each of the multiple measurement points so that each of the acquired measured values ​​becomes each of the individual target values ​​calculated.

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