Water treatment system and method of operating a water treatment system

Abstract

The water treatment system includes: an EDI (100); a pump (200) that supplies treated water to the EDI (100); a pressure gauge (300) that measures the output pressure of the treated water from the pump (200); and a control unit (400) that controls the discharge pressure of the pump so that the output pressure measured by the pressure gauge (300) at a given time becomes a given value.

Description

Technical Field

[0001] This invention relates to a water treatment system and a method for operating the water treatment system. Background Technology

[0002] Typically, the discharge volume of treated water from a water treatment system is controlled to fall within a given range. For example, as a control method for an electro-deionized water manufacturing device installed in a water treatment system, a technique is known to control the volume of concentrated water by using a valve to maintain it at a certain level or above in order to suppress scale formation caused by a reduction in the water supply (see, for example, Patent Document 1).

[0003] Existing technical documents Patent documents Patent Document 1: Japanese Patent No. 7103467 Summary of the Invention The problem that the invention aims to solve In the technology described in Patent Document 1, the control mechanism is complex in order to suppress the amount of water processed by the electro-deionized water manufacturing device.

[0004] The purpose of this invention is to provide a water treatment system and a method for operating the water treatment system that can achieve high energy-saving effects with a simple control method while suppressing the discharge of treated water from the electro-deionized water production device.

[0005] Technical solutions for solving the problem This invention provides a water treatment system, comprising: Electrodeionized water manufacturing equipment; A pump that supplies the water to be treated to the electro-deionized water manufacturing apparatus; A pressure gauge that measures the output pressure of the water being treated from the pump; and The control unit controls the discharge pressure of the pump so that the output pressure value measured by the pressure gauge at a given time interval becomes a given value.

[0006] In addition, the present invention provides a method for operating a water treatment system, comprising the following steps: Obtain the output pressure value of the water to be treated from the pump that supplies the water to be treated to the electro-deionized water production unit; and The pump discharge pressure is controlled so that the output pressure value becomes a given value at a given time interval.

[0007] Invention Effects In this invention, a high energy-saving effect can be achieved with a simple control method while suppressing the discharge of treated water from the electro-deionized water manufacturing device. Attached Figure Description

[0008] Figure 1 This is a diagram illustrating a first embodiment of the water treatment system of the present invention.

[0009] Figure 2 It is used for Figure 1 The flowchart illustrates an example of how a water treatment system operates.

[0010] Figure 3 This is a diagram illustrating a second embodiment of the water treatment system of the present invention.

[0011] Figure 4 It means Figure 3 The graph shows an example of the relationship between the rate of reduction in the pump's output pressure and the rate of reduction in the flow rate discharged from the EDI.

[0012] Figure 5 It means Figure 3 The graph shows an example of the relationship between the reduction rate of the pump's output pressure and the reduction rate of its power consumption.

[0013] Figure 6 It means Figure 3 The graph shows an example of the relationship between the reduction rate of the pump's output pressure and the concentration ratio in the EDI.

[0014] Figure 7 This is a diagram illustrating a third embodiment of the water treatment system of the present invention.

[0015] Figure 8 This is a diagram illustrating a fourth embodiment of the water treatment system of the present invention. Detailed Implementation

[0016] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0017] (First Implementation) Figure 1 This is a diagram illustrating a first embodiment of the water treatment system of the present invention. (See diagram below.) Figure 1 As shown, the water treatment system of this method includes an EDI (electrodeionized water production device) 100, a pump 200, a pressure gauge 300, a control unit 400, and a DC power supply device 500. In addition, flow meters 600-1 to 600-3 are installed along the path from the EDI 100. Figure 1The configuration shown can also be implemented in the primary pure water system within a water treatment system typically consisting of a pretreatment system, a primary pure water system, and a subsystem (secondary pure water system). Alternatively, a water treatment device, conductivity meter, resistivity meter, on / off valve, flow regulating valve, or flow meter can be installed between pump 200 and EDI 100 to provide a specific treatment for the treated water. Alternatively, a conductivity meter, resistivity meter, on / off valve, flow regulating valve, or flow meter can be installed downstream of EDI 100. When a water treatment device or conductivity meter is installed between pump 200 and EDI 100 to provide a specific treatment for the treated water, the pressure gauge 300 is preferably positioned directly behind pump 200.

[0018] The EDI100 is referred to as an electro-regenerated pure water system or a continuously regenerated pure water system. The EDI100 has a desalination chamber 100-1, a concentration chamber 100-2, and an electrode chamber 100-3 separated by cation exchange membranes and anion exchange membranes. The desalination chamber 100-1 is filled with at least one of a cation exchange resin and anion exchange resin. In the EDI100, a direct current flows from a direct current power supply 500 between the anode and cathode, continuously regenerating the ion exchange resins while removing ions contained in the treated water supplied to the EDI100 within the desalination chamber 100-1. Ions removed from the treated water within the desalination chamber 100-1 move to the concentration chamber 100-2 and are discharged as concentrated water. The treated water with ions removed in the desalination chamber 100-1 is discharged as desalinated water. The treated water discharged from the desalination chamber 100-1, concentration chamber 100-2, and electrode chamber 100-3 is supplied to the required locations via separate paths. Flow meter 600-1 measures the flow rate of desalinated water discharged from desalination chamber 100-1. Flow meter 600-2 measures the flow rate of concentrated water discharged from concentration chamber 100-2. Flow meter 600-3 measures the flow rate of electrode water discharged from electrode chamber 100-3. Furthermore, concentration chamber 100-2 of EDI100 also functions as electrode chamber 100-3; therefore, electrode chamber 100-3 may not be included in EDI100. In cases where the structure of EDI100 is such that concentration chamber 100-2 also functions as electrode chamber 100-3, the electrode water line passing from electrode chamber 100-3 through flow meter 600-3 is omitted.

[0019] Pump 200 draws in external water to be treated and supplies it to EDI 100. Pump 200 operates based on a drive signal from control unit 400. For example, pump 200 causes the motor to rotate at a speed based on the drive signal from control unit 400, drawing in the water to be treated and discharging it.

[0020] Pressure gauge 300 measures the output pressure of the water being treated from pump 200 at the outlet of pump 200. Pressure gauge 300 notifies the control unit 400 of the measured output pressure value.

[0021] The control unit 400 acquires the output pressure value measured by the pressure gauge 300. The control unit 400 controls the discharge pressure of the pump 200 via an inverter, ensuring that the output pressure value acquired from the pressure gauge 300 at a given time interval becomes a set value. When the maximum capacity value of the pump 200's discharge pressure is set to 100%, the control unit 400 controls the discharge pressure of the pump 200, resulting in a pressure reduction rate of 0-60%. This maximum capacity value can be a predetermined value based on the specifications of the pump 200, the maximum value that the pump 200 can discharge in the water treatment system in use, or the pump discharge pressure value in a normal mode other than the power-saving mode. If the pump 200 has a mechanism using an electric motor, the control unit 400 outputs a drive signal to the pump 200, which controls the motor's rotational speed, ensuring that the output pressure value measured by the pressure gauge 300 becomes a set value.

[0022] For example, upon receiving an external input indicating a switch to energy-saving mode, the control unit 400 acquires the output pressure value measured by the pressure gauge 300. The control unit 400 compares the acquired output pressure value with a value set for the energy-saving mode. Based on the comparison result, the control unit 400 calculates the rate at which the motor speed of the pump 200 is reduced. The control unit 400 outputs a control signal to the pump 200 corresponding to the calculated reduction rate. The method for calculating the rate at which the motor speed of the pump 200 is reduced could be, for example, pre-correlating the rate at which the output pressure value is reduced to the value set for the energy-saving mode with the rate at which the motor speed is reduced, and then performing the calculation based on this correlation. Alternatively, the method for calculating the rate at which the motor speed of the pump 200 is reduced could be a method that reduces the output pressure value by a certain percentage and adjusts it in stages to the output pressure value required for the requested water volume. This allows for the reduction of power consumption at a desired timing.

[0023] Additionally, for example, the control unit 400 acquires the output pressure value measured by the pressure gauge 300. The control unit 400 compares the acquired output pressure value with the pressure value corresponding to the requested flow rate in the system downstream of EDI 100. Based on the comparison result, the control unit 400 calculates the rate at which the motor speed of pump 200 is reduced. The control unit 400 outputs a control signal to pump 200 corresponding to the calculated reduction rate. The pressure value corresponding to the requested flow rate at this time is obtained according to a preset correlation between the requested flow rate and the pressure value. The method for calculating the rate at which the motor speed of pump 200 is reduced could be, for example, a method that pre-correlates the rate at which the output pressure value is reduced to the pressure value corresponding to the requested flow rate with the rate at which the motor speed is reduced, and performs the calculation based on this correlation. Alternatively, the method for calculating the rate at which the motor speed of pump 200 is reduced could be a method that reduces the output pressure value by a certain percentage and adjusts it in stages to the output pressure value that corresponds to the requested water volume. In this way, the output of pump 200 is controlled to be an output pressure value suitable for the system request from downstream. This allows for the reduction of electricity consumption without excessive water production.

[0024] Additionally, for example, in a pre-set timetable, during a period when the system operates in a power-saving mode set for nighttime or holidays, the control unit 400 acquires the output pressure value measured by the pressure gauge 300. The control unit 400 compares the acquired output pressure value with a value set for the power-saving mode. Based on the comparison result, the control unit 400 calculates the rate by which the speed of the pump 200's motor decreases. The control unit 400 outputs a control signal to the pump 200 corresponding to the calculated decrease rate. The method for calculating the rate by which the speed of the pump 200's motor decreases at this time can also be the same as described above. Furthermore, when returning from the power-saving mode to the normal mode, the control unit 400 acquires the output pressure value measured by the pressure gauge 300, compares the acquired output pressure value with a value set for the normal mode, calculates the rate by which the speed of the pump 200's motor increases based on the comparison result, and outputs a control signal to the pump 200 corresponding to the calculated increase rate. In this way, the control unit 400 controls the output of the pump 200 to the output pressure value corresponding to the operating mode. Therefore, power consumption can be reduced according to the schedule used to reduce power consumption.

[0025] Alternatively, for example, the control unit 400 can also perform control based on the operating status of systems downstream of EDI 100 (e.g., the number of operating systems). The control unit 400 acquires the output pressure value measured by the pressure gauge 300. The control unit 400 compares the acquired output pressure value with the pressure value corresponding to the operating status. Based on the comparison result, the control unit 400 calculates the rate at which the motor speed of the pump 200 is reduced. The control unit 400 outputs a control signal to the pump 200 corresponding to the calculated reduction rate. The pressure value corresponding to the current operating status is obtained according to a preset correlation between the operating status and the pressure value. The method for calculating the rate at which the motor speed of the pump 200 is reduced could, for example, be a method of pre-correlating the rate at which the output pressure value is reduced to the pressure value corresponding to the operating status with the rate at which the motor speed is reduced, and then performing the calculation based on this correlation. Alternatively, the method for calculating the rate at which the motor speed of the pump 200 is reduced could be a method of gradually adjusting the output pressure value to the output pressure value corresponding to the operating status by reducing the output pressure value by a certain percentage. In this way, the control unit 400 controls the output of the pump 200 to an output pressure value suitable for the operating conditions of the downstream system. As a result, power consumption can be reduced without excessive water production.

[0026] Alternatively, for example, the control unit 400 can also perform control based on the upstream water production volume of the EDI 100. The control unit 400 acquires the output pressure value measured by the pressure gauge 300. The control unit 400 compares the acquired output pressure value with the pressure value corresponding to the upstream water production volume. Based on the comparison result, the control unit 400 calculates the rate at which the motor speed of the pump 200 is reduced. The control unit 400 outputs a control signal corresponding to the calculated reduction rate to the pump 200. The pressure value corresponding to the upstream water production volume at this time is obtained according to a pre-set correlation between the upstream water production volume and the pressure value. The method for calculating the rate at which the motor speed of the pump 200 is reduced can be, for example, a method that pre-correlates the rate at which the output pressure value is reduced to the pressure value corresponding to the upstream water production volume with the rate at which the motor speed is reduced, and performs the calculation based on this correlation. Alternatively, the method for calculating the rate at which the motor speed of the pump 200 is reduced can be a method that reduces the output pressure value by a certain percentage and adjusts it in stages to the output pressure value corresponding to the upstream water production volume. In this way, the control unit 400 controls the output of pump 200 to an output pressure value suitable for the water production volume upstream. As a result, power consumption can be reduced without producing excessive water.

[0027] The following is about Figure 1 The operation method of the water treatment system shown in the diagram is explained. Figure 2 It is used for Figure 1The flowchart illustrates an example of how the water treatment system operates. The following describes an example of the process during a time period in a pre-set timetable when the system is in power-saving mode.

[0028] First, the control unit 400 determines whether the current time is for the energy-saving mode (step S1). This determination is based on a preset schedule and the date and time shown on the clock. In this schedule, for each time period or date (e.g., weekday or season), it is set which operating mode the water treatment system should operate in, either the normal mode or the energy-saving mode.

[0029] When the timing determines that the current mode is power-saving, the control unit 400 acquires the output pressure value of the pump 200 measured by the pressure gauge 300 (step S2). Next, the control unit 400 compares the acquired output pressure value with the value set for the output pressure during power-saving mode. Based on the comparison result, the control unit 400 calculates the rate at which the motor speed of the pump 200 is reduced (step S3). At this time, the control unit 400 can also calculate the rate at which the motor speed of the pump 200 is reduced based on a preset target pressure value. The control unit 400 outputs a control signal corresponding to the calculated reduction rate to the pump 200, controlling the discharge pressure of the pump 200 (step S4).

[0030] In this way, the control unit 400 controls the discharge pressure of the pump 200, so that the output pressure value of the pump 200, measured by the pressure gauge 300 installed at the discharge port of the pump 200 that supplies treated water to the EDI 100, becomes a given value. The timing of this control is based on external requests, the operating status of the downstream system, the water supply from the upstream system, or a schedule with set operating modes. Therefore, when suppressing the discharge of treated water from the electro-deionized water production unit to provide an appropriate volume of treated water, the power consumption of the pump 200 can be reduced, resulting in high energy savings. In cases where there is no water demand from the supply destination or other external sources, the system typically operates by circulating the treated water within the system to suppress the discharge of treated water from the electro-deionized water production unit. In this case, the water temperature rises due to the heat input from the pump. It is known that the boron removal performance of the EDI deteriorates when the water temperature rises. On the other hand, in this method, the speed of the motor of the pump 200 is reduced to suppress the discharge of treated water from the electro-deionized water production unit. This control prevents water temperature from rising due to pump heat input during circulation, and avoids a decrease in boron removal rate by maintaining continuous operation within the normal temperature range.

[0031] (Second Implementation) Figure 3 This is a diagram illustrating a second embodiment of the water treatment system of the present invention. (See diagram below.) Figure 3 As shown, in this water treatment system, in addition to being equipped with Figure 1 The components of the first embodiment shown also include a branch path 700 and flow regulating valves 800-1 to 800-3.

[0032] Branch path 700 branches off from the path originating from pump 200 to the desalination chamber 100-1, concentration chamber 100-2, and electrode chamber 100-3 of EDI 100. The branching point of branch path 700 is located near EDI 100 at the point where pressure gauge 300 measures the output pressure of pump 200. The treated water discharged from pump 200 is supplied to desalination chamber 100-1, concentration chamber 100-2, and electrode chamber 100-3 respectively via branch path 700. Furthermore, in the case where the structure of EDI 100 is such that concentration chamber 100-2 also serves as electrode chamber 100-3, the electrode water line from flow regulating valve 800-3 through electrode chamber 100-3 and flow meter 600-3 is omitted.

[0033] Flow regulating valve 800-1 is installed in branch path 700 supplying treated water to desalination chamber 100-1. Flow regulating valve 800-1 is a valve that regulates the flow rate of the treated water supplied to desalination chamber 100-1. Alternatively, flow regulating valve 800-1 can also be installed at the outlet of desalination chamber 100-1. Flow regulating valve 800-2 is installed in branch path 700 supplying treated water to concentration chamber 100-2. Flow regulating valve 800-2 is a valve that regulates the flow rate of the treated water supplied to concentration chamber 100-2. Alternatively, flow regulating valve 800-2 can also be installed at the outlet of concentration chamber 100-2. Flow regulating valve 800-3 is installed in branch path 700 supplying treated water to electrode chamber 100-3. Flow regulating valve 800-3 is a valve that regulates the flow rate of the treated water supplied to electrode chamber 100-3. Alternatively, the flow regulating valve 800-3 can also be installed at the outlet of the electrode chamber 100-3.

[0034] Figure 4 It means Figure 3 The graph shows an example of the relationship between the rate of reduction in the output pressure of pump 200 and the rate of reduction in the flow rate discharged from EDI 100. Figure 4 This indicates the rate at which the flow rates of desalinated water discharged from desalination chamber 100-1 (measured by flow meter 600-1) and concentrated water discharged from concentration chamber 100-2 (measured by flow meter 600-2) decrease according to the reduction rate of the output pressure of pump 200. This is the result obtained experimentally. Figure 4As shown, when the reduction rate of the output pressure of pump 200 increases, the reduction rate of the flow rate of demineralized water and concentrate also increases. The proportion of the increase in the flow rate reduction rate relative to the increase in the reduction rate of the output pressure of pump 200 differs between demineralized water and concentrate. It can be seen that even the reduction rate of the discharge flow rate of demineralized water, which is most easily affected by the flow rate of the treated water supplied to EDI 100, is lower than the reduction rate of the output pressure of pump 200. Therefore, as long as the pressure reduction does not exceed 60% of the maximum capacity of pump 200 in this water treatment system, the flow rate of treated water discharged from EDI 100 can be controlled without monitoring.

[0035] Figure 5 It means Figure 3 The graph shows an example of the relationship between the reduction rate of the output pressure value of pump 200 and the reduction rate of power consumption. (See example graph.) Figure 5 As shown, when the reduction rate of the output pressure value of pump 200 increases, the reduction rate of the power consumption of pump 200 also increases. Therefore, it can be seen that the reduction rate of the power consumption of pump 200 is higher than the reduction rate of the output pressure value. Thus, it is evident that reducing the output pressure value of pump 200 results in significant power savings.

[0036] Figure 6 It means Figure 3 The graph shows an example of the relationship between the reduction rate of the output pressure of pump 200 and the concentration ratio in EDI 100. The concentration ratio refers to the proportion of the inlet water volume to the concentrate volume of EDI 100. Figure 6 As shown, when the reduction rate of the output pressure of pump 200 increases, the concentration ratio does not increase, but remains unchanged or decreases. This is a result obtained through experiments. Therefore, it is possible to maintain or reduce the concentration ratio in EDI100 without using flow control valves 800-1 to 800-3 to control the supply of treated water to EDI100. By monitoring the pump discharge pressure and reducing the pump output, the risk of problems (such as scale or sludge) caused by the increase in concentration ratio can be reduced.

[0037] In this way, the treated water from pump 200 to EDI 100 branches from the main path to branch paths, and is supplied to desalination chamber 100-1, concentration chamber 100-2 and electrode chamber 100-3 via each branch path. If the supply to desalination chamber 100-1, concentration chamber 100-2 and electrode chamber 100-3 is pre-adjusted by the flow regulating valves 800-1 to 800-3 installed in each branch path, then the supply of treated water to EDI 100 can be changed (reduced) in the direction of reducing the concentration ratio simply by controlling the output pressure value of pump 200 without significantly changing the ratio of desalinated water to concentrated water.

[0038] (Third implementation method) Figure 7 This is a diagram illustrating a third embodiment of the water treatment system of the present invention. (See diagram below.) Figure 7 As shown, the water treatment system of this method is Figure 3 The system shown in the second embodiment replaces the control unit 400 with the control unit 401.

[0039] In addition to having, the control unit 401 has Figure 1 or Figure 3 In addition to the functions of the control unit 400 shown, it also has the function of calculating the rate of reduction of the current flowing from the DC power supply device 500 to the EDI 100 based on the rate of reduction of the output pressure value of the pump 200. This calculation method can be a method of pre-calculating the correlation between the rate of reduction of the output pressure value of the pump 200 and the rate of reduction of the current flowing from the DC power supply device 500 to the EDI 100 (e.g., a formula or an algorithm deriving one from the other), and using the calculated correlation to calculate the rate of reduction of the current flowing from the DC power supply device 500 to the EDI 100. Alternatively, the calculation method can also be a method of pre-associating (establishing a correlation) the rate of reduction of the output pressure value of the pump 200 and the rate of reduction of the current flowing from the DC power supply device 500 to the EDI 100, and calculating the rate of reduction of the current flowing from the DC power supply device 500 to the EDI 100 based on this correlation. The timing for the control unit 401 to control based on the calculated rate of reduction of the current value can be the timing of receiving an input from an external source indicating a switch to a power-saving mode. Furthermore, the timing for the control unit 401 to control based on the calculated rate of decrease in current value can also be the timing for switching to power-saving mode within a preset timetable. Additionally, the timing for the control unit 401 to control based on the calculated rate of decrease in current value can be the same as, or different from, the timing for reducing the output pressure of pump 200.

[0040] In this way, the control unit 401 reduces the output pressure of the pump 200 and, based on the rate of reduction, reduces the current flowing from the DC power supply device 500 to the EDI 100. This results in greater energy savings. Furthermore, the control unit 401 of this method can also be applied to the EDI 100 of the first embodiment.

[0041] (Fourth Implementation) Figure 8 This is a diagram illustrating a fourth embodiment of the water treatment system of the present invention. (See diagram below.) Figure 8 As shown, the water treatment system in this method consists of three groups. Figure 3 The system shown is a parallel connection of EDI100s.

[0042] The treated water from pump 200 is supplied to the three EDIs 100-102. Additionally, direct current flows from each of the DC power supply units 500-502 to EDIs 100-102. Treated water is supplied from pump 200 to the desalination chamber 100-1, concentration chamber 100-2, and electrode chamber 100-3 of EDI 100 via flow control valves 800-1-800-3 located in branch path 700. Treated water is also supplied from pump 200 to the desalination chamber 101-1, concentration chamber 101-2, and electrode chamber 101-3 of EDI 101 via flow control valves 801-1-801-3 located in branch path 700. Water to be treated is supplied from pump 200 to the desalination chamber 102-1, concentration chamber 102-2, and electrode chamber 102-3 of EDI 102 via flow regulating valves 802-1 to 802-3 located in branch path 700. The treated water discharged from the desalination chamber 100-1 of EDI 100, the desalination chamber 101-1 of EDI 101, and the desalination chamber 102-1 of EDI 102 is combined and supplied downstream as desalinated water. The treated water discharged from the concentration chamber 100-2 of EDI 100, the concentration chamber 101-2 of EDI 101, and the concentration chamber 102-2 of EDI 102 is combined and supplied downstream as concentrated water. The treated water discharged from the electrode chamber 100-3 of EDI 100, the electrode chamber 101-3 of EDI 101, and the electrode chamber 102-3 of EDI 102 is combined and supplied downstream as electrode water. Furthermore, the location of flow control valves 800-1 to 800-3 is not limited to upstream of EDI100. For example, flow control valve 800-1 may also be located at the outlet of desalination chamber 100-1. Additionally, flow control valve 800-2 may be located at the outlet of concentration chamber 100-2. Flow control valve 800-3 may also be located at the outlet of electrode chamber 100-3. Alternatively, flow control valves may be installed at the upstream section (before the branch point) or downstream section (merging point) of branch path 700, instead of flow control valves 800-1 to 800-3. Furthermore, in the case where the structure of EDI100 is such that concentration chamber 100-2 also serves as electrode chamber 100-3, the electrode water line from flow control valve 800-3 through electrode chamber 100-3 and flow meter 600-3 is omitted.

[0043] Thus, in a system with multiple EDIs connected in parallel, by controlling the pumps 200 of the first to third embodiments solely through the control unit 400, the ratio of demineralized water to concentrated water discharged from each of the multiple EDIs can be changed (reduced) in the direction of decreasing the concentration ratio. In this way, even in systems where multiple EDIs are connected in parallel or series, excess water production can be eliminated, and power consumption can be reduced. Furthermore, in the parallel configuration of multiple EDIs 100 in the first embodiment, the second embodiment, and the third embodiment (EDIs 100-102), various control methods can naturally be implemented.

[0044] The present invention has been described above with reference to the embodiments, but the present invention is not limited to the above embodiments. Various modifications that can be understood by those skilled in the art to the structure or details of the present invention can be made within the scope of the present invention.

[0045] The application claims priority based on Japanese Application Special Hoc 2023-216824 filed on December 22, 2023, and all of its disclosures are incorporated herein by reference.

Claims

1. A water treatment system, comprising: Electrodeionized water manufacturing equipment; A pump that supplies the water to be treated to the electro-deionized water manufacturing apparatus; A pressure gauge that measures the output pressure of the water being treated from the pump; and The control unit controls the discharge pressure of the pump so that the output pressure value measured by the pressure gauge at a given time interval becomes a given value.

2. The water treatment system according to claim 1, wherein, The water treatment system has the following features: Branch paths, which branch off from the path initiated by the pump to the desalination chamber and concentration chamber of the electro-deionized water production apparatus, respectively; and A flow regulating valve, which is disposed on at least one of the branch paths. The pressure gauge is positioned closer to the pump than the branch point from the path to the branch path.

3. The water treatment system according to claim 1 or 2, wherein, When the control unit receives a given input from the outside, it controls the discharge pressure of the pump so that the output pressure value measured by the pressure gauge becomes a given value.

4. The water treatment system according to claim 1 or 2, wherein, The control unit controls the pump's discharge pressure based on at least one of the requested flow rate in the system downstream of the electro-deionized water manufacturing device, the water production rate upstream of the electro-deionized water manufacturing device, and the operating status of the system downstream of the electro-deionized water manufacturing device, so that the output pressure value measured by the pressure gauge becomes a given value.

5. The water treatment system according to claim 1 or 2, wherein, The control unit controls the pump's discharge pressure based on a given schedule, such that the output pressure value measured by the pressure gauge becomes a given value.

6. The water treatment system according to claim 1 or 2, wherein, The control unit controls the pump's discharge pressure so that, when the maximum capacity of the discharge pressure is set to 100%, the pressure reduction rate is 0 to 60%.

7. The water treatment system according to claim 1 or 2, wherein, The water treatment system has multiple electro-deionized water manufacturing devices, which are connected in parallel or in series.

8. A method for operating a water treatment system, comprising the following steps: Obtain the output pressure value of the water to be treated from the pump that supplies the water to be treated to the electro-deionized water production unit; and The pump discharge pressure is controlled so that the output pressure value becomes a given value at a given time interval.

Images