JP2014108381A - Pure water producing apparatus and pure water producing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pure water producing apparatus and a pure water producing method capable of easily and safely adjusting the average operating pressure of a reverse osmosis membrane module.SOLUTION: A pure water producing apparatus 1 comprises: reverse osmosis membrane modules 11 and 12 for separating supply water W1 into permeated water W4 and concentrated water W5; a pressure pump 5 for discharging the supply water W1 to the reverse osmosis membrane modules 11 and 12; a supply water line L1 for circulating the supply water W1 to the reverse osmosis membrane modules 11 and 12; a permeated water line L3 for circulating the permeated water W4 to an electric deionization stack 20; an inverter 6 for driving the pressure pump 5; a control part 30 capable of controlling a drive frequency or a driving voltage output from the inverter 6; and an input interface part 32 for receiving manual input for adjustment in order to adjust the drive frequency or driving voltage and reception permission input to allow receiving input for adjustment.

Description

  The present invention relates to a pure water production apparatus and a pure water production method including a reverse osmosis membrane module that separates permeate from supply water, and an electrodeionization stack that demineralizes permeate to obtain demineralized water.

  In semiconductor manufacturing processes, electronic component cleaning, medical instrument cleaning, and the like, high-purity pure water that does not contain impurities is used. When manufacturing this kind of pure water, a pure water manufacturing apparatus may be used. As pure water production equipment, reverse osmosis membrane module (hereinafter also referred to as “RO membrane module”) that separates permeate from feed water, and permeate separated by reverse osmosis membrane module is desalted to obtain demineralized water. An electrodeionization stack to be obtained (hereinafter also referred to as “EDI stack”) is known (see, for example, Patent Document 1). In such a pure water production apparatus, in general, raw water such as groundwater or tap water is treated with an RO membrane module using a reverse osmosis membrane, so that permeated water from which most of the dissolved salts have been removed from the raw water. To separate. Thereafter, the purity is further increased by purifying the permeate with an EDI stack.

JP 2001-259376 A

  By the way, in order to separate the permeated water from the feed water using the RO membrane module, it is necessary to apply a pressure higher than the osmotic pressure of the feed water to the primary side of the membrane by a pressurizing pump. The pressure applied to the feed water in the RO membrane module is called the average operating pressure. In a system where the osmotic pressure difference and the secondary pressure do not change substantially, the average operating pressure (effective pressure) is kept constant. The production of permeated water at the required flow rate is maintained. However, if the temperature of the raw water used as the supply water decreases, the viscosity of the supply water increases and the water permeability coefficient of the RO membrane decreases, so it is necessary to keep the average operating pressure constant during the season when the raw water temperature decreases. There arises a problem that it becomes impossible to obtain a permeated water having a flow rate. Conventionally, various means and methods have been proposed for adjusting the average operating pressure in a pure water production apparatus, but a function that can be adjusted more easily and safely is desired.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a pure water production apparatus and a pure water production method capable of easily and safely adjusting the average operating pressure of a reverse osmosis membrane module. And

  The present invention includes a water storage tank that stores supply water, a reverse osmosis membrane module that separates supply water into permeate and concentrated water, a pressure pump that discharges supply water toward the reverse osmosis membrane module, and a permeation An electrodeionization stack for demineralizing water to obtain demineralized water, a feedwater line for flowing feedwater to the reverse osmosis membrane module, a permeate line for flowing permeate to the electrodeionization stack, An inverter for driving the pressurizing pump, a control unit capable of controlling the drive frequency or drive voltage output from the inverter, a manual adjustment input for adjusting the drive frequency or drive voltage, and the adjustment input It is related with a pure water manufacturing apparatus provided with the input interface part which receives the reception permission input for enabling accepting.

  The reverse osmosis membrane module includes a first reverse osmosis membrane module and a second reverse osmosis membrane module, and the first reverse osmosis membrane module separates supply water into first permeable water and first concentrated water. The pressurizing pump discharges supply water toward the first reverse osmosis membrane module, and the second reverse osmosis membrane module separates the first permeate into second permeate and second concentrated water. The electrodeionization stack demineralizes the second permeate to obtain demineralized water, the supply water line circulates the supply water to the first reverse osmosis membrane module, and the permeate line is , A first permeate line and a second permeate line, wherein the first permeate line allows the first permeate to flow through the second reverse osmosis membrane module, and the second permeate line includes a second permeate line. It is preferable to pass permeate through the electrodeionization stack.

  In addition, a temperature sensor that detects the temperature of the supplied water in the water storage tank or the temperature of the second permeated water in the second permeated water line, the control unit, based on the temperature detected by the temperature sensor, It is preferable to control the inverter so that the flow rate of the second permeated water becomes a preset target flow rate value.

  Moreover, this invention is a method of manufacturing a pure water using the pure water manufacturing apparatus provided with the said 1st reverse osmosis membrane module and the said 2nd reverse osmosis membrane module, Comprising: A part of 1st concentrated water is said water storage Adjusting a flow rate of the first concentrated water flowing through the first concentrated water return line to a first predetermined flow rate value by a first valve provided in the first concentrated water return line to be returned to the tank; The step of adjusting the flow rate of the first concentrated water flowing through the first concentrated water discharge line to a second predetermined flow rate value by the second valve provided in the first concentrated water discharge line for discharging the remaining water to the outside of the apparatus. And a third valve provided in a second concentrated water return line for returning the second concentrated water to the water storage tank, the flow rate of the second concentrated water flowing through the second concentrated water return line is set to a third predetermined flow rate value. Adjusting to the first And confirming whether or not the flow rate of the permeated water is a fourth predetermined flow rate value, and when the flow rate of the second permeated water is not the fourth predetermined flow rate value, the discharge of the pressurizing pump The present invention relates to a pure water production method further comprising a step of adjusting the flow rate of the feed water so that the flow rate of the second permeated water becomes a fourth predetermined flow rate value by the feed water valve provided on the side.

  A step of adjusting the flow rate of the demineralized water to a fifth predetermined flow rate value by a fourth valve provided in the demineralization chamber inflow line for allowing the second permeate to flow into the demineralization chamber of the electrodeionization stack; Adjusting the flow rate of the concentrated water to a sixth predetermined flow rate value by a fifth valve provided in the concentration chamber inflow line for allowing the 2 permeated water to flow into the concentration chamber of the electrodeionization stack; A step of adjusting the flow rate of the electrode water to the seventh predetermined flow rate value by a sixth valve provided in the electrode chamber inflow line for flowing into the electrode chamber of the electrodeionization stack; And confirming whether or not the flow rate of the desalted water is not the fifth predetermined flow rate value, the supply water valve so that the flow rate of the desalted water becomes the fifth predetermined flow rate value. To adjust the flow rate of the feed water. Preferably further comprising a.

  ADVANTAGE OF THE INVENTION According to this invention, the pure water manufacturing apparatus and the pure water manufacturing method which can adjust the average operation pressure of a reverse osmosis membrane module easily and safely can be provided.

It is a whole block diagram of the pure water manufacturing apparatus 1 which concerns on 1st Embodiment. It is a whole block diagram of the pure water manufacturing apparatus 1A which concerns on the modification of 1st Embodiment. It is a flowchart which shows the operation step of the 2nd permeate flow rate adjustment process of the pure water manufacturing method which concerns on 1st Embodiment. It is a flowchart which shows the operation step of the desalted water flow rate adjustment process of the pure water manufacturing method which concerns on 1st Embodiment.

  A pure water production apparatus 1 and a pure water production method according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an overall configuration diagram of a pure water production apparatus 1 according to the first embodiment. The pure water production apparatus 1 according to the present embodiment is applied to, for example, a pure water production apparatus that produces demineralized water from raw water (for example, tap water). The desalted water produced by the pure water production apparatus is sent as pure water to a demand location or the like. In the pure water production apparatus of the present embodiment, supplying pure water to a demand location or the like is also referred to as “water sampling”.

  As shown in FIG. 1, the pure water manufacturing apparatus 1 according to the present embodiment includes an activated carbon filter 2, a prefilter 3, a raw water tank 4 as a water storage tank, a pressurizing pump 5, an inverter 6, and a reverse First RO membrane module 11 and second RO membrane module 12 as osmotic membrane modules, EDI stack 20 as electrodeionization stack, control unit 30, notification unit 31, input operation unit 32, DC power supply device 33, Is provided.

  The pure water production apparatus 1 includes a raw water replenishment valve 61, a first flow path switching valve 62, a second flow path switching valve 63, a third flow path switching valve 64, a desalted water return valve 65, 1 RO valve 101 to 4 RO valve 104, 1st EDI valve 201 to 6th EDI valve 206, water level sensor 41, in-tank electrical conductivity sensor 42, in-tank temperature sensor 43, and 1st electrical conductivity sensor 51 The pressure sensor 52, the first flow sensor 53, the second flow sensor 54, the second electrical conductivity sensor 55, the third flow sensor 56, the fourth flow sensor 57, the raw water pressure sensor 581, and the concentration A water pressure sensor 582, a first concentrated water flow sensor 591, a second concentrated water flow sensor 592, and a third concentrated water flow sensor 593 are provided.

  In FIG. 1, the electrical connection path is omitted, but the control unit 30 performs the raw water supply valve 61, the first flow path switching valve 62, the second flow path switching valve 63, the water level sensor 41, and the electric conductivity in the tank. Sensor 42, tank internal temperature sensor 43, first electrical conductivity sensor 51, second electrical conductivity sensor 55, pressure sensor 52, first flow sensor 53, second flow sensor 54, third flow sensor 56, fourth flow rate The sensor 57, the raw water pressure sensor 581, the concentrated water pressure sensor 582, the first concentrated water flow rate sensor 591, the second concentrated water flow rate sensor 592, and the third concentrated water flow rate sensor 593 are electrically connected. Moreover, in this embodiment, the 3rd flow-path switching valve 64, the desalted water return valve 65, the 1st RO valve 101-the 4th RO valve 104, and the 1st EDI valve 201-the 6th EDI valve 206 switch an open / close state by manual operation. Or the valve opening degree can be adjusted.

  The pure water production apparatus 1 also includes a raw water line L1 as a supply water line, a first permeate line L2 and a second permeate line L3 as permeate lines, and a first RO concentration as a first concentrate return line. A water return line L5, a first RO concentrated water discharge line L41 as a first concentrated water discharge line, a second RO concentrated water return line L6 as a second concentrated water return line, a second RO permeated water return line L7, 2 RO permeated water discharge line L42, a desalted water line L8, a desalted water return line L9, an EDI concentrated water return line L10, an EDI concentrated water discharge line L43, and an EDI electrode water discharge line L44. The “line” in the present specification is a general term for lines capable of flowing a fluid such as a flow path, a radial path, and a pipeline.

  Raw water W1 (supply water) flows through the raw water line L1. The raw water line L1 is a line through which the raw water W1 is circulated to the first RO membrane module 11. The raw water line L1 includes a first raw water line L11 and a second raw water line L12.

  The first raw water line L11 is a line connecting a supply source (not shown) of the raw water W1 and the raw water tank 4. The upstream end of the first raw water line L11 is connected to a supply source (not shown) of the raw water W1. Further, the downstream end of the first raw water line L <b> 11 is connected to the raw water tank 4.

  The first raw water line L11 is provided with a raw water supply valve 61, a raw water pressure sensor 581, an activated carbon filter 2, a prefilter 3, and a raw water tank 4 in order from the upstream side. The raw water supply valve 61 is a valve capable of opening and closing the first raw water line L11. The raw water supply valve 61 is electrically connected to the control unit 30. The opening / closing operation of the raw water supply valve 61 is controlled by a flow path opening / closing signal from the control unit 30.

  The activated carbon filter 2 is a device that removes a chlorine component (mainly free chlorine) contained in the raw water W1. The activated carbon filter 2 has a filter medium bed made of activated carbon in a pressure tank. The activated carbon filter 2 purifies the raw water W1 by decomposing and removing chlorine components contained in the raw water W1, and adsorbing and removing organic components and capturing suspended substances.

  The prefilter 3 is a filter that removes fine particles contained in the raw water W1 filtered by the activated carbon filter 2. The prefilter 3 is configured by accommodating a filter element in a housing. As the filter element, for example, a nonwoven fabric filter element or a thread wound filter element having a filtration accuracy of 1 to 50 μm is used. The raw water tank 4 is a tank that stores the raw water W1 purified through the activated carbon filter 2 and the prefilter 3 as supply water and supplies the raw water W1 to the pressurizing pump 5.

  The second raw water line L12 is a line connecting the raw water tank 4 and the first RO membrane module 11. The upstream end of the second raw water line L12 is connected to the raw water tank 4. Further, the downstream end of the second raw water line L12 is connected to the primary inlet port (the inlet of the raw water W1) of the first RO membrane module 11. The second raw water line L12 circulates raw water W1 as supply water to the first RO membrane module 11.

  In the second raw water line L12, a pressurizing pump 5, a first RO valve 101 as a supply water valve, and a first RO membrane module 11 are provided in this order from the upstream side. The first RO valve 101 is provided between the pressurizing pump 5 and the first RO membrane module 11 in the second raw water line L12. That is, the first RO valve 101 is provided on the discharge side of the pressurizing pump 5. The first RO valve 101 is a valve capable of adjusting the flow rate of the raw water W1 flowing through the second raw water line L12.

  The pressurizing pump 5 is a device that sucks raw water W1 as supply water flowing through the second raw water line L12, discharges the raw water W1 toward the first RO membrane module 11, and pumps it. Driving power having a converted frequency (or voltage) is supplied from the inverter 6 to the pressurizing pump 5. The pressurizing pump 5 is driven at a rotational speed corresponding to the supplied drive power frequency (hereinafter also referred to as “drive frequency”) or the drive power voltage (hereinafter also referred to as “drive voltage”).

  The inverter 6 is an electric circuit (or a device having the circuit) that supplies driving power whose frequency or voltage is converted to the pressure pump 5. The inverter 6 is electrically connected to the control unit 30. A command signal is input to the inverter 6 from the control unit 30. The inverter 6 drives the pressurization pump 5 by outputting the drive power of the drive frequency (or drive voltage) corresponding to the command signal (current value signal or voltage value signal) input by the control unit 30 to the pressurization pump 5. To do. That is, the control unit 30 can control the drive frequency or drive voltage output from the inverter 6.

  The first RO membrane module 11 as the first reverse osmosis membrane module is composed of the raw water W1 pumped by the pressurizing pump 5, the first permeated water W2 from which dissolved salts are removed, and the first concentrated water from which dissolved salts are concentrated. And W3. The first RO membrane module 11 is configured by accommodating a single or a plurality of spiral RO membrane elements in a pressure vessel (vessel). Examples of the RO membrane used in the RO membrane element include a crosslinked aromatic polyamide composite membrane. Examples of RO membrane elements composed of a crosslinked aromatic polyamide composite membrane include: Toray Industries, Inc .: model name “TMG20-400”, Eunjin Chemical Co., Ltd .: model name: “RE8040-BLF”, Nitto Denko Corporation: model name: “ESPA1” Are commercially available, and these elements can be suitably used.

  The first RO concentrated water return line L5 is a line for circulating a part of the first concentrated water W3 separated by the first RO membrane module 11 to the raw water tank 4 and returning it. The first RO concentrated water return line L5 includes an upstream first RO concentrated water return line L51 and a downstream first RO concentrated water return line L52.

  The upstream end of the upstream first RO concentrated water return line L51 is connected to the primary outlet port (the outlet of the first concentrated water W3) of the first RO membrane module 11. The downstream end of the upstream first RO concentrated water return line L51 is branched into a downstream first RO concentrated water return line L52 and a first RO concentrated water discharge line L41 at a branch portion J11.

  The upstream end of the downstream first RO concentrated water return line L52 is connected to the branch portion J11. The downstream end of the downstream first RO concentrated water return line L52 is connected to the raw water tank 4. The downstream first RO concentrated water return line L52 is provided with a second RO valve 102 as a first valve. The 2nd RO valve 102 is a valve which can adjust the flow volume of the 1st concentrated water W3 which distribute | circulates the downstream 1st RO concentrated water return line L52.

  The 1st RO concentrated water discharge line L41 is a line which distribute | circulates so that the remainder of the 1st concentrated water W3 isolate | separated by the 1st RO membrane module 11 may be discharged | emitted out of the apparatus from the middle of the 1st RO concentrated water return line L5. . The upstream end of the first RO concentrated water discharge line L41 is connected to the branch portion J11. The downstream side of the first RO concentrated water discharge line L41 is connected or opened to a drain pit (not shown), for example. The first RO concentrated water discharge line L41 is provided with a third RO valve 103 as a second valve. The third RO valve 103 is a valve capable of adjusting the drainage flow rate of the first concentrated water W3 discharged out of the apparatus via the first RO concentrated water discharge line L41.

  The first permeate line L <b> 2 is a line through which the first permeate W <b> 2 separated by the first RO membrane module 11 flows to the second RO membrane module 12. The upstream end of the first permeate line L2 is connected to the secondary port (the outlet of the first permeate W2) of the first RO membrane module 11. The downstream end of the first permeate line L2 is connected to the primary inlet port (the inlet of the first permeate W2) of the second RO membrane module 12.

  The second RO membrane module 12 is composed of the first permeated water W2 separated by the first RO membrane module 11 and pumped by the pressurizing pump 5, and the second permeated water W4 from which dissolved salts are removed from the first permeated water W2. And the second concentrated water W5 in which the dissolved salts are concentrated. The second RO membrane module 12 is configured by accommodating a single or a plurality of spiral RO membrane elements in a pressure vessel (vessel). Also in the second RO membrane module 12, the same RO membrane element as that in the first RO membrane module 11 can be used.

  The second RO concentrated water return line L6 is a line through which the second concentrated water W5 separated by the second RO membrane module 12 is circulated to the raw water tank 4 and returned. The upstream end of the second RO concentrated water return line L6 is connected to the primary outlet port (the outlet of the second concentrated water W5) of the second RO membrane module 12. The downstream end of the second RO concentrated water return line L6 is connected to the raw water tank 4. The second RO concentrated water return line L6 is provided with a fourth RO valve 104 as a third valve. The fourth RO valve 104 is a valve capable of adjusting the flow rate of the second concentrated water W5 flowing through the second RO concentrated water return line L6.

  The second permeated water line L3 is a line through which the second permeated water W4 separated by the second RO membrane module 12 flows through the EDI stack 20. The second permeate line L3 includes a front-stage permeate line L31, a middle-stage permeate line L32, a desalting chamber inflow line L321, a concentration chamber inflow line L322, and an electrode chamber inflow line L323.

  The upstream end of the front-stage permeate line L31 is connected to the secondary port (the outlet of the second permeate W4) of the second RO membrane module 12. The downstream end of the front-stage permeate line L31 is connected to the middle-stage permeate line L32 and the second RO permeate return line L7 via the first flow path switching valve 62.

  The first flow path switching valve 62 allows the second permeated water W4 separated by the second RO membrane module 12 to flow toward the EDI stack 20 via the middle-stage permeated water line L32 (water sampling side flow path). ) Or a valve that can be switched to a flow path (circulation side flow path and drain side flow path) that flows toward the third flow path switching valve 64 via the second RO permeate return line L7. The first flow path switching valve 62 is configured by, for example, an electric or electromagnetic three-way valve. The first flow path switching valve 62 is electrically connected to the control unit 30. The switching of the flow path in the first flow path switching valve 62 is controlled by a flow path switching signal from the control unit 30.

  The second RO permeated water return line L7 is a line for returning the second permeated water W4 separated by the second RO membrane module 12 to the raw water tank 4 on the upstream side of the first RO membrane module 11. The second RO permeate return line L7 includes an upstream second RO permeate return line L71 and a downstream second RO permeate return line L72.

  The upstream end of the upstream second RO permeate return line L71 is connected to the first flow path switching valve 62. The downstream end of the upstream second RO permeate return line L71 is connected to the third flow path switching valve 64.

  The third flow path switching valve 64 allows the second permeated water W4 flowing through the upstream second RO permeate return line L71 to flow toward the raw water tank 4 via the downstream second RO permeate return line L72. This is a valve that can be switched to a channel (circulation side channel) or a channel (drainage side channel) that circulates so as to be discharged to the outside of the apparatus via the second RO permeated water discharge line L42. The third flow path switching valve 64 is a valve that can be manually switched between open and closed states.

  The upstream end of the downstream second RO permeate return line L72 is connected to the third flow path switching valve 64. The downstream end of the downstream second RO permeate return line L72 is connected to the raw water tank 4.

  The second RO permeate discharge line L42 is a line through which the second permeate W4 separated by the second RO membrane module 12 joins the second RO permeate return line L7 and is discharged out of the apparatus. The upstream end of the second RO permeate discharge line L42 is connected to the third flow path switching valve 64. The downstream side of the third flow path switching valve 64 is connected or opened to a drainage pit (not shown), for example.

  The second RO permeated water discharge line L42 is joined to the first RO concentrated water discharge line L41 at the connection portion J12. The connection part J12 is arrange | positioned rather than the 3rd RO valve 103 in the 1st RO concentrated water discharge line L41. The portion of the second RO permeated water discharge line L42 on the downstream side of the connection portion J12 is common to the portion of the first RO concentrated water discharge line L41 on the downstream side of the connection portion J12.

  The upstream end of the middle permeate line L32 is connected to the first flow path switching valve 62. The downstream end of the middle-stage permeate line L32 is branched into a desalting chamber inflow line L321, a concentration chamber inflow line L322, and an electrode chamber inflow line L323 at a branch portion J4.

  The downstream ends of the desalination chamber inflow line L321, the enrichment chamber inflow line L322, and the electrode chamber inflow line L323 are the primary ports of the EDI stack 20 (each inlet side of the desalination chamber 21, the concentration chamber 22, and the electrode chamber 23). )It is connected to the.

  The EDI stack 20 is a water treatment device that desalinates the second permeated water W4 separated from the first permeated water W2 by the second RO membrane module 12 to obtain desalted water W6, concentrated water W7, and electrode water W8. is there. The EDI stack 20 is electrically connected to the DC power supply device 33. A DC voltage is input from the DC power supply device 33 to the EDI stack 20. The EDI stack 20 is energized and operated by the DC voltage input from the DC power supply device 33.

  The DC power supply device 33 applies a DC voltage between the pair of electrodes of the EDI stack 20. The DC power supply device 33 is electrically connected to the control unit 30. The DC power supply device 33 outputs a DC voltage to the EDI stack 20 in response to the command signal input by the control unit 30.

  In the EDI stack 20, a cation exchange membrane and an anion exchange membrane (not shown) are alternately arranged between a pair of electrodes. The inside of the EDI stack 20 is partitioned into a desalting chamber 21, a concentration chamber 22, and an electrode chamber 23 by these ion exchange membranes. The desalting chamber 21 is filled with an ion exchanger (not shown). As the ion exchanger filled in the desalting chamber 21, for example, an ion exchange resin, an ion exchange fiber, or the like is used. In FIG. 1, a plurality of desalting chambers 21, concentration chambers 22, and electrode chambers 23 partitioned inside the EDI stack 20 are schematically shown.

  A desalting chamber inflow line L321 through which the second permeated water W4 flows is connected to the inlet side of the desalting chamber 21. On the outlet side of the desalting chamber 21, a desalting water line L <b> 8 through which the desalted water W <b> 6 discharged from the desalting chamber 21 is removed is connected. A concentrating chamber inflow line L322 through which the second permeated water W4 flows is connected to the inlet side of the concentrating chamber 22. An EDI concentrated water return line L10 that circulates the concentrated water W7 that has been concentrated and discharged is connected to the outlet side of the concentration chamber 22. An electrode chamber inflow line L323 through which the second permeated water W4 flows is connected to the inlet side of the electrode chamber 23. An electrode water discharge line L44 through which the electrode water W8 flows is connected to the outlet side of the electrode chamber 23.

  The desalination chamber inflow line L321 is provided with a first EDI valve 201 as a fourth valve. The first EDI valve 201 is a valve capable of adjusting the flow rate of the second permeated water W4 flowing through the demineralization chamber inflow line L321 (that is, the flow rate of the demineralized water W6 flowing through the demineralization chamber 21). A second EDI valve 202 as a fifth valve is provided in the concentrating chamber inflow line L322. The second EDI valve 202 is a valve capable of adjusting the flow rate of the second permeated water W4 flowing through the concentration chamber inflow line L322 (that is, the flow rate of the concentrated water W7 flowing through the concentration chamber 22). The electrode chamber inflow line L323 is provided with a third EDI valve 202 as a sixth valve. The third EDI valve 203 is a valve capable of adjusting the flow rate of the second permeated water W4 flowing through the electrode chamber inflow line L323 (that is, the flow rate of the electrode water W8 flowing through the electrode chamber 23).

  The second permeated water W4 flowing through the second permeated water line L3 flows into each of the desalting chamber 21, the concentration chamber 22, and the electrode chamber 23. Residual ions contained in the second permeated water W4 are captured by an ion exchanger (not shown) filled in the desalting chamber 21 to become desalted water W6. The desalted water W6 is sent to the demand point via the desalted water line L8 (described later). Further, residual ions captured by the ion exchanger in the desalting chamber 21 move to the concentration chamber 22 by the applied electric energy. And the water containing a residual ion is discharged | emitted as the concentrated water W7 from the concentration chamber 22 via the EDI concentrated water return line L10 and the EDI concentrated water discharge line L43 (after-mentioned). The second permeated water W4 that has flowed into the electrode chamber 23 is discharged out of the apparatus as electrode water W8 from the electrode chamber 23 via the EDI electrode water discharge line L44.

  The desalted water line L8 is a line that sends the desalted water W6 obtained in the EDI stack 20 as pure water toward the demand point. The demineralized water line L8 includes an upstream demineralized water line L81 and a downstream demineralized water line L82.

  The upstream end of the upstream demineralized water line L81 is connected to the secondary port of the EDI stack 20 (the outlet side of the demineralized chamber 21). The downstream end of the upstream demineralized water line L81 is connected to the downstream demineralized water line L82 and the demineralized water return line L9 (described later) via the second flow path switching valve 63.

  The second flow path switching valve 63 is a flow path (water sampling side flow path) for sending the desalted water W6 obtained in the desalination chamber 21 of the EDI stack 20 toward the demand point via the downstream desalted water line L82. ) Or a valve that can be switched to a flow path (circulation side flow path) that circulates toward the raw water tank 4 via the desalted water return line L9. The second flow path switching valve 63 is configured by, for example, an electric or electromagnetic three-way valve. The second flow path switching valve 63 is electrically connected to the control unit 30. Switching of the flow path in the second flow path switching valve 63 is controlled by a flow path switching signal from the control unit 30.

  The second flow path switching valve 63 performs a process of sending the demineralized water W6 obtained in the EDI stack 20 from the demineralized water line L8 to the demand point by being switched to the water sampling side flow path by the control unit 30. It functions as an executable sending means.

  An upstream end portion of the downstream demineralized water line L <b> 82 is connected to the second flow path switching valve 63. The downstream end of the downstream desalted water line L82 is connected to a device or the like (not shown) at the demand point.

  The desalted water return line L9 is a line for returning the desalted water W6 obtained in the desalting chamber 21 of the EDI stack 20 to the raw water tank 4 on the upstream side of the first RO membrane module 11 from the middle of the desalted water line L8. . In the present embodiment, the upstream end of the desalted water return line L9 is connected to the second flow path switching valve 63. The downstream end of the desalted water return line L9 is connected to the raw water tank 4. The desalted water return line L <b> 9 returns the desalted water W <b> 6 obtained in the desalting chamber 21 of the EDI stack 20 to the raw water tank 4. A desalted water return valve 65 is provided in the desalted water return line L9.

  The EDI concentrated water return line L10 is a line that joins the concentrated water W7 discharged from the concentration chamber 22 of the EDI stack 20 to the desalted water return line L9 and returns it to the raw water tank 4. The upstream end of the EDI concentrated water return line L10 is connected to the secondary port of the EDI stack 20 (the outlet side of the concentration chamber 22). The downstream end of the EDI concentrated water return line L10 is connected to the raw water tank 4.

  The EDI concentrated water return line L10 is joined to the demineralized water return line L9 at the connection J13. The connecting portion J13 is disposed between the raw water tank 4 and the desalted water return valve 65 in the desalted water return line L9. The portion downstream of the connection portion J13 in the EDI concentrated water return line L10 is common to the portion from the connection portion J13 to the raw water tank 4 in the desalted water return line L9. A fifth EDI valve 205 is provided on the upstream side of the connection portion J13 in the EDI concentrated water return line L10.

  The EDI concentrated water discharge line L43 is a line through which the concentrated water W7 discharged from the concentration chamber 22 of the EDI stack 20 is circulated so as to be discharged out of the apparatus from the middle of the EDI concentrated water return line L10. The upstream end portion of the EDI concentrated water discharge line L43 is connected to the connection portion J9. The connecting portion J9 is disposed between the concentrating chamber 22 and the fifth EDI valve 205 in the EDI concentrated water return line L10. The downstream side of the EDI concentrated water discharge line L43 is connected or opened to a drain pit (not shown), for example. A sixth EDI valve 206 is provided in the EDI concentrated water discharge line L43.

  The electrode water discharge line L44 is a line through which the electrode water W8 discharged from the electrode chamber 23 of the EDI stack 20 is circulated out of the apparatus. The upstream end of the electrode water discharge line L44 is connected to the electrode chamber 23 of the EDI stack 20. The electrode water discharge line L44 is joined to the EDI concentrated water discharge line L43 at the connection portion J10. The connecting portion J10 is disposed on the downstream side of the sixth EDI valve 206 in the EDI concentrated water discharge line L43. A portion of the electrode water discharge line L44 on the downstream side of the connection portion J10 is common to a portion of the EDI concentrated water discharge line L43 on the downstream side of the connection portion J10.

  The water level sensor 41 is a device that measures the water level of the raw water W1 stored in the raw water tank 4. The water level sensor 41 is disposed on the lower side inside the raw water tank 4. Further, the water level sensor 41 is electrically connected to the control unit 30. The water level of the raw water tank 4 measured by the water level sensor 41 is transmitted to the control unit 30 as a detection signal. In the present embodiment, the water level sensor 41 is a continuous level sensor, and for example, a capacitive sensor, a pressure sensor, an ultrasonic sensor, or the like is used. FIG. 1 shows an example in which a pressure sensor is provided on the outer wall surface near the bottom of the raw water tank 4 as the water level sensor 41. The water level sensor 41 is not limited to a continuous level sensor, and may be a level switch, for example. The level switch is a preset liquid level position detector, and is configured to detect, for example, a plurality of liquid level positions. As the level switch, for example, a float type or an electrode type is used.

  The in-tank electrical conductivity sensor 42 is a device that measures the electrical conductivity of the raw water W1 stored in the raw water tank 4. The in-tank electrical conductivity sensor 42 is disposed on the lower side inside the raw water tank 4.

  The 1st electrical conductivity sensor 51 is an apparatus which measures the electrical conductivity of the 2nd permeated water W4 which distribute | circulates the 2nd permeated water line L3. The first electrical conductivity sensor 51 is connected to the second permeated water line L3 at the connection portion J1. The connection portion J1 is disposed between the second RO membrane module 12 and the first flow path switching valve 62 in the second permeated water line L3. The 2nd electrical conductivity sensor 55 is an apparatus which measures the electrical conductivity of the desalted water W6 which distribute | circulates the desalted water line L8. The second electrical conductivity sensor 55 is connected to the demineralized water line L8 at the connection portion J6. The connecting portion J6 is disposed between the EDI stack 20 and the fourth EDI valve 204 in the desalted water line L8.

  The in-tank electrical conductivity sensor 42, the first electrical conductivity sensor 51, and the second electrical conductivity sensor 55 are electrically connected to the control unit 30. The electrical conductivity of the raw water W1 measured by the in-tank electrical conductivity sensor 42, the electrical conductivity of the second permeated water W4 measured by the first electrical conductivity sensor 51, and the second electrical conductivity sensor 55 were measured. The electrical conductivity of the desalted water W6 is transmitted to the control unit 30 as a detection signal.

  The in-tank temperature sensor 43 is a device that measures the temperature of the raw water W <b> 1 as supply water stored in the raw water tank 4. The tank internal temperature sensor 43 is disposed on the lower side of the raw water tank 4. The tank internal temperature sensor 43 is electrically connected to the control unit 30. The temperature of the raw water W1 measured by the tank temperature sensor 43 is transmitted to the control unit 30 as a detection signal.

  The first flow rate sensor 53 is a device that measures the flow rate of the second permeated water W4 flowing through the second permeated water line L3. The first flow rate sensor 53 is connected to the second permeated water line L3 at the connection portion J3. The connecting portion J3 is disposed between the second RO membrane module 12 and the first flow path switching valve 62 in the second permeated water line L3. The second flow rate sensor 54 is a device that measures the flow rate of the desalted water W6 that flows through the desalted water line L8. The second flow rate sensor 54 measures the flow rate of the water flowing through the desalting chamber 21 by measuring the flow rate of the desalted water W6 flowing through the desalted water line L8. The second flow rate sensor 54 is connected to the desalted water line L8 at the connection portion J5. The connecting portion J5 is disposed between the EDI stack 20 and the fourth EDI valve 204 in the desalted water line L8.

  The third flow rate sensor 56 is a device that measures the flow rate of the second permeated water W4 flowing through the concentration chamber inflow line L322. The third flow rate sensor 56 measures the flow rate of the water flowing through the concentration chamber 22 by measuring the flow rate of the second permeated water W4 flowing through the concentration chamber inflow line L322. The third flow sensor 56 is connected to the enrichment chamber inflow line L322 at the connection portion J7. The connecting portion J7 is disposed between the EDI stack 20 and the second EDI valve 202 in the concentration chamber inflow line L322. The fourth flow rate sensor 57 is a device that measures the flow rate of the second permeated water W4 flowing through the electrode chamber inflow line L323. The fourth flow rate sensor 57 measures the flow rate of the water flowing through the electrode chamber 23 by measuring the flow rate of the second permeated water W4 flowing through the electrode chamber inflow line L323. The fourth flow rate sensor 57 is connected to the electrode chamber inflow line L323 at the connection portion J8. The connecting portion J8 is disposed between the electrode chamber 23 of the EDI stack 20 and the third EDI valve 203 in the electrode chamber inflow line L323.

  The first concentrated water flow sensor 591 is a device that measures the flow rate of the first concentrated water W3 flowing through the downstream first RO concentrated water return line L52. The first concentrated water flow sensor 591 is connected to the downstream side first RO concentrated water return line L52 at the connection portion J22. The connecting portion J22 is disposed between the second RO valve 102 in the downstream first RO concentrated water return line L52 and the raw water tank 4. The second concentrated water flow sensor 592 is a device that measures the flow rate of the first concentrated water W3 flowing through the first RO concentrated water discharge line L41. The second concentrated water flow sensor 592 is connected to the first RO concentrated water discharge line L41 at the connection portion J23. The connection part J23 is arrange | positioned between the 3rd RO valve 103 in the 1st RO concentrated water discharge line L41, and the connection part J12. The third concentrated water flow rate sensor 593 is a device that measures the flow rate of the second concentrated water W5 flowing through the second RO concentrated water return line L6. The third concentrated water flow rate sensor 593 is connected to the second RO concentrated water return line L6 at the connection portion J24. The connecting portion J24 is disposed between the fourth RO valve 104 and the second RO membrane module 12 in the second RO concentrated water return line L6.

  The first flow sensor 53, the second flow sensor 54, the third flow sensor 56, the fourth flow sensor 57, the first concentrated water flow sensor 591, the second concentrated water flow sensor 592, and the third concentrated water flow sensor 593 are: The control unit 30 is electrically connected. The flow rate of the second permeate water W4 measured by the first flow rate sensor 53, the flow rate of the desalted water W6 measured by the second flow rate sensor 54, the flow rate of the second permeate water W4 measured by the third flow rate sensor 56, 4, the flow rate of the second permeate W 4 measured by the flow sensor 57, the return flow rate of the first concentrate W 3 measured by the first concentrate flow sensor 591, and the first concentration measured by the second concentrate flow sensor 592. The discharge flow rate of the water W3 and the return flow rate of the second concentrated water W5 measured by the third concentrated water flow rate sensor 593 are transmitted to the control unit 30 as detection signals.

  The pressure sensor 52 is a device that measures the pressure of the second permeated water W4 flowing through the second permeated water line L3. The pressure sensor 52 is connected to the second permeated water line L3 at the connection portion J2. The pressure sensor 52 is electrically connected to the control unit 30. The connecting portion J2 is disposed between the second RO membrane module 12 and the first flow path switching valve 62. The pressure of the second permeated water W4 measured by the pressure sensor 52 is transmitted to the control unit 30 as a detection signal.

  The raw water pressure sensor 581 is a device that measures the pressure of the raw water W1 flowing through the first raw water line L11. The raw water pressure sensor 581 is connected to the first raw water line L11 at the connection portion J21. The raw water pressure sensor 581 is electrically connected to the control unit 30. The connecting portion J21 is disposed between the raw water supply valve 61 and the activated carbon filter 2. The pressure of the raw water W1 measured by the raw water pressure sensor 581 is transmitted to the control unit 30 as a detection signal.

  The concentrated water pressure sensor 582 is a device that measures the pressure of the first concentrated water W3 flowing through the upstream first RO concentrated water return line L51. The concentrated water pressure sensor 582 is connected to the upstream first RO concentrated water return line L51 at the connection portion J25. The concentrated water pressure sensor 582 is electrically connected to the control unit 30. The connecting part J25 is disposed between the first RO membrane module 11 and the branch part J11. The pressure of the first concentrated water W3 measured by the concentrated water pressure sensor 582 is transmitted to the control unit 30 as a detection signal.

  The notification unit 31 notifies a predetermined alarm. The notification unit 31 is electrically connected to the control unit 30. The notification is, for example, one or more of display, sound, light emission, and the like. That is, the notification unit 31 includes one or more of a display device (liquid crystal display or the like), a buzzer, a speaker, a lamp, and the like.

  The input operation unit 32 is an input for accepting an input operation of a user or an administrator for selection related to the operation mode of the device (for example, selection of operation / stop, release of alarm, etc.) and various settings related to the operation condition of the device. It is an interface part. The input operation unit 32 includes an operation panel that combines a display and button switches, a touch panel that allows direct input operation on the display, and the like. The input operation unit 32 is electrically connected to the control unit 30. Information input from the input operation unit 32 is transmitted to the control unit 30.

  In changing various settings related to the operating conditions of the apparatus, the control unit 30 requests an input for accepting setting change, specifically, input of a password via the input operation unit 32. This password is determined in advance by a user or an administrator and registered in the control unit 30. When an accurate password is input via the input operation unit 32, the control unit 30 permits acceptance of setting changes. On the other hand, when an incorrect password is input via the input operation unit 32, the control unit 30 rejects acceptance of the setting change.

  When the control unit 30 allows the setting change to be accepted, the user or the administrator can perform adjustment input for adjusting the drive frequency or drive voltage of the pressurizing pump 5. Specifically, the control unit 30 receives the target output value (0 to 100%) of the inverter 6 input via the input operation unit 32, and stores this setting information in the memory. And the control part 30 performs control which adjusts the drive frequency or drive voltage of the pressurization pump 5 based on the setting information which concerns on the target output value of the inverter 6 at the time of sampling of pure water. The target output value of the inverter 6 is determined so that the flow rate of the second permeated water W4 becomes a target flow rate value (including a nearby value) under the temperature conditions of the raw water W1 and the second permeated water W4. For example, it is determined on the basis of a functional expression or a data table that is 100% when the temperature is 5 ° C. and 25% when the temperature is 35 ° C.

  Next, the control unit 30 will be described. The control unit 30 is configured by a microprocessor (not shown) including a CPU and a memory. In the control unit 30, various programs for controlling the pure water production apparatus 1 are stored in the memory of the microprocessor. Further, in the microprocessor memory, for example, a password necessary for permission to accept the setting change, setting information related to the target output value of the inverter 6, a function expression or data for adjusting the driving frequency or driving voltage of the pressurizing pump 5. A table or the like is stored.

  In the control unit 30, the CPU of the microprocessor executes various controls described later according to a predetermined program read from the memory. In the control unit 30, an integrated timer unit for managing time measurement and the like is incorporated in the microprocessor.

  The control unit 30 controls the inverter 6 and changes the driving frequency or driving voltage output from the inverter 6 to the pressurizing pump 5. This control includes a first inverter control based on the setting information related to the target output value of the inverter 6 and a second inverter control based on the temperature detected by the in-tank temperature sensor 43. It is operated selectively in consideration of the characteristics. Each will be described below.

<First inverter control>
In this control, the output (drive frequency or drive voltage) from the inverter 6 to the pressure pump 5 is adjusted so as to be the target output value (0 to 100%). As described above, the target output value of the inverter 6 is the setting information input by the user or the administrator via the input operation unit 32 through the input of the password, and the maximum drive frequency (for example, 60 Hz) of the pressure pump 5. ) Or as a percentage of the maximum drive voltage (eg, 200V). The rotational speed control of the pressurization pump 5 includes frequency control and voltage control. When frequency control is used, the target output value is set as a percentage with respect to the maximum drive frequency of the pressurization pump 5. . On the other hand, when using voltage control, the target output value is set as a percentage of the maximum drive voltage of the pressurizing pump 5.

  In executing this control, the user or administrator periodically (for example, every month) refers to the temperature detected by the tank temperature sensor 43 to grasp the seasonal temperature change of the raw water W1. When a change of, for example, 5 ° C. or more is observed with respect to the previous detected temperature, the target output value of the inverter 6 is reviewed based on the current detected temperature. In this review, regarding the target output value at which the flow rate of the second permeated water W4 becomes the target flow rate value (including the vicinity value), the relationship between the temperature of the raw water W1 and the target output value obtained experimentally in advance (for example, a functional equation) And provided in the data table), the target output value setting information is changed. The relationship between the temperature of the raw water W1 and the target output value is such that the lower the temperature, the higher the output. As illustrated above, when the temperature is 5 ° C., 100%, and when the temperature is 35 ° C. The relationship is 25%.

<Second inverter control>
In this control, the output (drive frequency or drive voltage) from the inverter 6 to the pressure pump 5 is adjusted based on the temperature detected by the tank temperature sensor 43. That is, the control unit 30 controls the temperature feedforward water amount for the inverter 6 so that the value of the flow rate of the second permeated water W4 becomes a preset target flow rate value based on the temperature detected by the tank temperature sensor 43. Take control. The rotation speed control of the pressurizing pump 5 has two types of frequency control and voltage control. When frequency control is used, the drive frequency is within a range below the maximum drive frequency (for example, 60 Hz) of the pressurization pump 5. Automatically adjusted. On the other hand, when the voltage control is performed, the drive voltage is automatically adjusted in a range equal to or less than the maximum drive voltage (for example, 200 V) of the pressure pump 5.

  In executing this control, the user or the administrator sets the target flow rate value of the second permeated water W4 via the input operation unit 32 in advance. This target flow rate value is determined, for example, by adding the drainage flow rate generated in the EDI stack 20 to the maximum flow rate of pure water required at the demand point. In addition, in the memory of the microprocessor of the control unit 30, the temperature of the raw water W1 obtained experimentally in advance for the drive frequency or drive voltage at which the flow rate of the second permeated water W4 becomes the target flow rate value (including the vicinity value). (For example, function formulas and data tables) are stored. In the temperature feedforward water amount control, the control unit 30 refers to the detected temperature of the in-tank temperature sensor 43 in real time (for example, in a cycle of 100 ms) and determines a driving frequency or a driving voltage according to the detected temperature. And the control part 30 controls the inverter 6 so that the pressurization pump 5 may be driven with the determined drive frequency or drive voltage. The relationship between the temperature of the raw water W1 and the inverter output (drive frequency or drive voltage) is such that the output increases as the temperature decreases.

  According to the pure water manufacturing apparatus 1 which concerns on this embodiment mentioned above, the following effects are show | played, for example. The pure water production apparatus 1 includes a control unit 60 that can control the drive frequency or drive voltage output from the inverter 6, a manual target output value (adjustment input) for adjusting the drive frequency or drive voltage, a target An input operation unit 32 (input interface unit) that receives a password (acceptance permission input) for enabling an output value is provided. For this reason, the average operating pressure of the reverse osmosis membrane module can be easily adjusted simply by resetting the target output value of the inverter 6 according to the temperature change of the raw water W1. In addition, a password is required to change the setting of the target output value, and only those who are familiar with the characteristics of the apparatus can change the setting. Therefore, the average operating pressure of the RO membrane module can be adjusted safely without causing a shortage of pure water flow.

  Moreover, the control part 30 can also perform temperature feedforward water volume control instead of the control adjusted so that an inverter output may become a target output value. In the temperature feedforward water amount control, the control unit 30 controls the inverter 6 so that the flow rate value of the second permeate water W4 becomes a preset target flow rate value based on the temperature detected by the tank temperature sensor 43. Control is performed. If the temperature of the raw water W1 is low, the viscosity of the feed water increases and the water permeability coefficient of the RO membrane decreases. Moreover, if the temperature of raw | natural water W1 is high, the viscosity of feed water will become low and the water permeability coefficient of RO membrane will improve. When the drive frequency or drive voltage output from the inverter 6 is constant, the rotation speed of the pressure pump 5 is driven at a constant value, so that the average operating pressure is maintained, but the temperature change of the raw water W1 The value of the flow rate of the second permeated water W4 changes due to the change in the water permeation coefficient due to the above.

  However, if the temperature detected by the in-tank temperature sensor 43 is high, the control unit 30 controls the inverter 6 to lower the drive frequency or drive voltage output from the inverter 6. Conversely, if the temperature detected by the in-tank temperature sensor 43 is low, the control unit 30 controls the inverter 6 to increase the drive frequency or drive voltage output from the inverter 6. For this reason, even if the water permeability coefficient of the RO membrane changes, the average operating pressure of the RO membrane module can be easily adjusted. As a result, the flow rate value of the second permeated water W4 can be maintained at a preset target flow rate value.

  Next, a pure water producing apparatus 1A according to a modification of the first embodiment will be described with reference to the drawings. FIG. 2 is an overall configuration diagram of a pure water producing apparatus 1A according to a modification of the first embodiment. The pure water manufacturing apparatus 1A is different from the pure water manufacturing apparatus 1 according to the first embodiment in that it does not include the tank temperature sensor 43 and includes the second permeate line temperature sensor 43A. Then, the controller 30A controls the inverter 6 so that the flow rate value of the second permeate water W4 becomes a preset target flow rate value based on the temperature detected by the second permeate line temperature sensor 43A. The point which controls is different from the pure water manufacturing apparatus 1 which concerns on 1st Embodiment. Except these points, it is the same as that of the pure water manufacturing apparatus 1 which concerns on 1st Embodiment. Therefore, about the same member as the pure water manufacturing apparatus 1 which concerns on 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The second permeate line temperature sensor 43A is a device that measures the temperature of the second permeate water W4 flowing through the front-stage permeate line L31. The second permeate line temperature sensor 43A is connected to the front-stage permeate line L31 at the connection portion J26. The second permeate line temperature sensor 43 </ b> A is electrically connected to the control unit 30. The connecting portion J26 is disposed between the second RO membrane module 12 and the first flow path switching valve 62. The temperature of the second permeate water W4 measured by the second permeate line temperature sensor 43A is transmitted to the control unit 30 as a detection signal.

  Based on the temperature detected by the second permeate line temperature sensor 43A, the controller 30 feeds a temperature feedforward to the inverter 6 so that the flow rate value of the second permeate water W4 becomes a preset target flow rate value. Control water volume. The rotation speed control of the pressurizing pump 5 has two types of frequency control and voltage control. When frequency control is used, the drive frequency is within a range below the maximum drive frequency (for example, 60 Hz) of the pressurization pump 5. Automatically adjusted. On the other hand, when the voltage control is performed, the drive voltage is automatically adjusted in a range equal to or less than the maximum drive voltage (for example, 200 V) of the pressure pump 5.

  In executing this control, the user or the administrator sets the target flow rate value of the second permeated water W4 via the input operation unit 32 in advance. This target flow rate value is determined, for example, by adding the drainage flow rate generated in the EDI stack 20 to the maximum flow rate of pure water required at the demand point. In addition, in the memory of the microprocessor of the control unit 30, the temperature of the raw water W1 obtained experimentally in advance for the drive frequency or drive voltage at which the flow rate of the second permeated water W4 becomes the target flow rate value (including the vicinity value). (For example, function formulas and data tables) are stored. In the temperature feedforward water amount control, the control unit 30 refers to the detected temperature of the second permeated water line temperature sensor 43A in real time (for example, in a cycle of 100 ms), and determines a driving frequency or a driving voltage corresponding to the detected temperature. And the control part 30 controls the inverter 6 so that the pressurization pump 5 may be driven with the determined drive frequency or drive voltage. The relationship between the temperature of the raw water W1 and the inverter output (drive frequency or drive voltage) is such that the output increases as the temperature decreases.

  The second permeate line temperature sensor 43A as a temperature sensor detects the temperature of the second permeate water W4 in the second permeate line L3. Generally, in the measurement of electrical conductivity, simultaneous measurement of temperature is also required for temperature compensation. Therefore, by providing the first electrical conductivity sensor 51 and the second permeated water line temperature sensor 43A in the second permeated water line L3, temperature compensation is possible in measuring the electrical conductivity of the second permeated water W4. For this reason, the control part 30 can measure the electrical conductivity of the 2nd permeate water W4 correctly, performing the control which maintains the value of the flow volume of the 2nd permeate water W4 to the preset target flow rate value. .

  Next, the pure water manufacturing method according to the first embodiment will be described. In the pure water manufacturing method here, the pure water manufacturing apparatus 1 or the pure water manufacturing apparatus 1A is used. In the pure water production method, the second permeated water flow rate adjustment process for adjusting the flow rate of the second permeated water W4 flowing through the second permeated water line L3 to the fourth predetermined flow rate value and the demineralized water line L8 are circulated. And a desalted water flow rate adjustment process for adjusting the flow rate of the desalted water W6 to a fifth predetermined flow rate value. FIG. 3 is a flowchart showing operation steps of the second permeate flow rate adjustment process. FIG. 4 is a flowchart showing the operation steps of the desalted water flow rate adjustment process.

  In the second permeated water flow rate adjustment process shown in FIG. 3, first, in step ST10, the first valve is operated to adjust the flow rate of the first concentrated water flowing through the first concentrated water return line to the first predetermined flow rate value. . Specifically, the second RO valve 102 is operated to adjust the flow rate of the first concentrated water W3 flowing through the first RO concentrated water return line L5 to the first predetermined flow rate value.

  In step ST11, the second valve is operated to adjust the flow rate of the first concentrated water flowing through the first concentrated water discharge line to the second predetermined flow rate value. Specifically, the third RO valve 103 is operated to adjust the flow rate of the first concentrated water W3 flowing through the first RO concentrated water discharge line L41 to the second predetermined flow rate value.

  In step ST12, the third valve is operated to adjust the flow rate of the second concentrated water flowing through the second concentrated water return line to the third predetermined flow rate value. Specifically, the fourth RO valve 104 is operated to adjust the flow rate of the second concentrated water W5 flowing through the second RO concentrated water return line L6 to the third predetermined flow rate value.

  In step ST13, it is confirmed whether or not the flow rate of the second permeated water W4 is the fourth predetermined flow rate value. When the flow rate of the second permeate water W4 is equal to the fourth predetermined flow rate value (YES), the second permeate flow rate adjustment process is finished and the process proceeds to step ST20 of the desalted water flow rate adjustment process. On the other hand, when the flow rate of the second permeated water W4 is not equal to the fourth predetermined flow rate value (NO), the process proceeds to step ST14.

  In step ST14, it is determined whether the flow rate of the second permeated water W4 is less than the fourth predetermined flow rate value or exceeds the fourth predetermined flow rate value. When the flow rate of the second permeated water W4 is less than the fourth predetermined flow rate value (YES), the process proceeds to step ST15. On the other hand, when the flow rate of the second permeated water W4 exceeds the fourth predetermined flow rate value (NO), the process proceeds to step ST16.

  In step ST15, the supply water valve provided on the discharge side of the pressurization pump is operated so that the flow rate of the second permeate flowing through the second permeate line becomes the fourth predetermined flow rate value. Adjust the flow rate. Specifically, by increasing the opening of the first RO valve 101 and increasing the flow rate of the raw water W1 flowing through the second raw water line L12, the second permeated water W4 flowing through the second permeated water line L3 is increased. The flow rate is adjusted to a fourth predetermined flow rate value. After the operation of step ST15, the process returns to step ST10, and the operation of adjusting the flow rate of each line is performed again.

  In step ST16, the supply water valve provided on the discharge side of the pressure pump is operated so that the flow rate of the second permeate flowing through the second permeate line becomes the fourth predetermined flow rate value. Adjust the flow rate. Specifically, by reducing the opening of the first RO valve 101 and decreasing the flow rate of the raw water W1 flowing through the second raw water line L12, the second permeated water W4 flowing through the second permeated water line L3 is reduced. The flow rate is adjusted to a fourth predetermined flow rate value. After the operation of step ST16, the process returns to step ST10, and the operation of adjusting the flow rate of each line is performed again.

  In the desalted water flow rate adjustment process shown in FIG. 4, first, in step ST20, the fourth valve provided in the desalting chamber inflow line is operated to adjust the flow rate of the desalted water to the fifth predetermined flow rate value. Specifically, the first EDI valve 201 provided in the desalting chamber inflow line L321 is operated to adjust the flow rate of the desalted water W6 to the fifth predetermined flow rate value.

  In step ST21, the fifth valve provided in the concentrating chamber inflow line is operated to adjust the flow rate of the concentrated water to the sixth predetermined flow rate value. Specifically, the second EDI valve 202 provided in the concentration chamber inflow line L322 is operated to adjust the flow rate of the concentrated water W7 to the sixth predetermined flow rate value.

  In step ST22, the sixth valve provided in the electrode chamber inflow line is operated to adjust the flow rate of the electrode water to the seventh predetermined flow rate value. Specifically, the third EDI valve 203 provided in the electrode chamber inflow line L323 is operated to adjust the flow rate of the electrode water W8 to the seventh predetermined flow rate value.

  In step ST23, it is confirmed whether or not the flow rate of the demineralized water W6 is the fifth predetermined flow rate value. When the flow rate of the desalted water W6 is equal to the fifth predetermined flow rate value (YES), the desalted water flow rate adjustment process is finished, and preparation for pure water sampling is performed. On the other hand, when the flow rate of the demineralized water W6 is not equal to the fifth predetermined flow rate value (NO), the process proceeds to step ST24.

  In step ST24, it is determined whether the flow rate of the desalted water W6 is less than a fifth predetermined flow rate value or exceeds a fifth predetermined flow rate value. When the flow rate of the desalted water W6 is less than the fifth predetermined flow rate value (YES), the process proceeds to step ST25. On the other hand, when the flow rate of the desalted water W6 exceeds the fifth predetermined flow rate value (YES), the process proceeds to step ST26.

  In step ST25, the supply water valve provided on the discharge side of the pressurization pump is operated to adjust the flow rate of the supply water so that the flow rate of the desalted water flowing through the desalination chamber becomes the fifth predetermined flow rate value. . Specifically, by increasing the opening of the first RO valve 101 and increasing the flow rate of the second permeated water W4 flowing through the second permeated water line L3, the desalted water W6 flowing through the desalted water line L8 is increased. The flow rate is adjusted to the fifth predetermined flow rate value. After the operation of step ST25, the process returns to step ST10, and an operation for adjusting the flow rate of each line is performed again.

  In step ST26, the supply water valve provided on the discharge side of the pressurizing pump is operated to adjust the flow rate of the supply water so that the flow rate of the desalted water flowing through the desalination chamber becomes the fifth predetermined flow rate value. . Specifically, by reducing the opening of the first RO valve 101 and reducing the flow rate of the second permeated water W4 flowing through the second permeated water line L3, the desalted water W6 flowing through the desalted water line L8 is reduced. The flow rate is adjusted to the fifth predetermined flow rate value. After the operation of step ST26, the process returns to step ST10, and the operation of adjusting the flow rate of each line is performed again.

  According to the second permeated water flow rate adjustment process of the pure water production method according to the present embodiment described above, for example, the following effects are exhibited. In the second permeate flow rate adjustment process, the flow rate of the first concentrated water W3 flowing through the first RO concentrated water return line L5, the flow rate of the first concentrated water W3 flowing through the first RO concentrated water discharge line L41, and the second RO concentrated concentration. The flow rate of the second concentrated water W5 flowing through the water return line L6 is sequentially adjusted so that these flow rates coincide with the respective predetermined flow rate values.

  In the adjustment of the flow rate of the RO membrane module, from the viewpoint of preventing the RO membrane fouling, it is most important to secure the circulation flow rate of the supply water on the primary side of the first RO membrane module 11 located in the foremost stage, and then the first RO membrane. Management of the concentration factor on the primary side of the module 11 is important. Therefore, by adjusting the flow rate in the above-described order, the required concentrated water return flow rate and discharge flow rate can be obtained reliably, and stable operation can be continued.

  Moreover, according to the demineralized water flow rate adjustment process of the pure water manufacturing method according to the present embodiment described above, for example, the following effects are exhibited. In the desalted water flow rate adjustment process, the desalted water W6 that flows through the desalting chamber 21, the flow rate of the concentrated water W7 that flows through the concentrating chamber 22, and the flow rate of the electrode water W8 that flows through the electrode chamber 23 are sequentially adjusted, These flow rates are made to coincide with the respective predetermined flow rate values.

  In the flow rate adjustment of the EDI stack, the production flow rate of demineralized water is the most important from the viewpoint of ensuring the required flow rate of pure water at the demand point, and then the management of the concentration rate in the concentration chamber is important. Therefore, by adjusting the flow rate in the order described above, the required flow rate of pure water can be reliably obtained, and stable operation can be continued.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and can be implemented in various forms. In the embodiment, the pure water production apparatus 1 has a configuration in which the first RO membrane module 11 and the second RO membrane module 12 are arranged in two stages in series so that the permeated water in the previous stage becomes the feed water in the subsequent stage. However, it is not limited to this. For example, the pure water production apparatus 1 may be configured such that three or more reverse osmosis membrane modules are connected in series.

  In the embodiment, the EDI stack 20 is configured such that the second permeated water W4 is individually supplied to the concentration chamber 22 and the electrode chamber 23, and the concentrated water W7 and the electrode water W8 are separated and discharged. However, it is not limited to this. For example, the EDI stack 20 may have a common distribution channel to the concentrating chamber 22 and the electrode chamber 23 in the inside thereof, and a common collecting channel from the concentrating chamber 22 and the electrode chamber 23. May be.

1 Pure water production equipment 4 Raw water tank (water storage tank)
5 Pressure pump 6 Inverter 11 1st RO membrane module (reverse osmosis membrane module, 1st reverse osmosis membrane module)
12 Second RO membrane module (reverse osmosis membrane module, second reverse osmosis membrane module)
20 EDI stack (Electrodeionization stack)
30 Control unit 32 Input operation unit (interface unit)
43 Tank temperature sensor 43
43A Second permeate line temperature sensor 101 First RO valve (supply water valve)
102 2nd RO valve (1st valve)
103 3rd RO valve (2nd valve)
104 4th RO valve (3rd valve)
201 1st EDI valve (4th valve)
202 2nd EDI valve (5th valve)
203 3rd EDI valve (6th valve)
L1 Raw water line (supply water line)
L2 1st permeate line (permeate line)
L3 Second permeate line (permeate line)
L5 1st RO concentrated water return line (1st concentrated water return line)
L6 2nd RO concentrated water return line (2nd concentrated water return line)
L41 1st RO concentrated water discharge line (1st concentrated water discharge line)
W1 Raw water (supply water)
W2 First permeate (permeate)
W3 1st concentrated water (concentrated water)
W4 Second permeated water (permeated water)
W5 Second concentrated water W6 Demineralized water W7 Concentrated water W8 Electrode water

Claims (5)

A water storage tank for storing the supply water;
A reverse osmosis membrane module that separates supply water into permeate and concentrated water;
A pressurizing pump for discharging supply water toward the reverse osmosis membrane module;
An electrodeionization stack for demineralizing the permeate to obtain demineralized water;
A supply water line for distributing supply water to the reverse osmosis membrane module;
A permeate line for allowing permeate to flow through the electrodeionization stack;
An inverter for driving the pressure pump;
A control unit capable of controlling the drive frequency or drive voltage output from the inverter;
An apparatus for producing pure water, comprising: an input for manual adjustment for adjusting the drive frequency or drive voltage; and an input interface unit for receiving an acceptance permission input for accepting the adjustment input. The reverse osmosis membrane module comprises a first reverse osmosis membrane module and a second reverse osmosis membrane module,
The first reverse osmosis membrane module separates supply water into first permeate and first concentrated water,
The pressurizing pump discharges supply water toward the first reverse osmosis membrane module,
The second reverse osmosis membrane module separates the first permeate into the second permeate and the second concentrated water,
The electrodeionization stack obtains demineralized water by demineralizing the second permeated water,
The supply water line distributes supply water to the first reverse osmosis membrane module,
The permeate line includes a first permeate line and a second permeate line,
The first permeate line distributes the first permeate to the second reverse osmosis membrane module,
The said 2nd permeated water line is a pure water manufacturing apparatus of Claim 1 which distribute | circulates a 2nd permeated water to the said electrodeionization stack. A temperature sensor for detecting the temperature of the supplied water in the water storage tank or the temperature of the second permeated water in the second permeated water line;
3. The control unit according to claim 2, wherein the control unit controls the inverter based on a temperature detected by the temperature sensor so that a flow rate of the second permeated water becomes a preset target flow rate value. Pure water production equipment. A method for producing pure water using the pure water production apparatus according to claim 2,
A flow rate of the first concentrated water flowing through the first concentrated water return line is set to a first predetermined flow rate by a first valve provided in the first concentrated water return line for returning a part of the first concentrated water to the water storage tank. Adjusting to the value,
The flow rate of the 1st concentrated water which distribute | circulates the said 1st concentrated water discharge line is made into the 2nd predetermined flow rate value by the 2nd valve provided in the 1st concentrated water discharge line which discharges the remainder of the 1st concentrated water outside the apparatus. Adjusting steps,
A flow rate of the second concentrated water flowing through the second concentrated water return line is adjusted to a third predetermined flow rate value by a third valve provided in the second concentrated water return line for returning the second concentrated water to the water storage tank. And steps to
Checking whether the flow rate of the second permeated water is a fourth predetermined flow rate value,
When the flow rate of the second permeated water is not the fourth predetermined flow rate value, the flow rate of the second permeated water becomes the fourth predetermined flow rate value by the supply water valve provided on the discharge side of the pressurizing pump. Thus, the pure water manufacturing method which further includes the step which adjusts the flow volume of supply water. Adjusting the flow rate of the demineralized water to a fifth predetermined flow rate value by a fourth valve provided in the demineralization chamber inflow line for allowing the second permeated water to flow into the demineralization chamber of the electrodeionization stack;
Adjusting the flow rate of the concentrated water to a sixth predetermined flow rate value by a fifth valve provided in the concentration chamber inflow line for allowing the second permeate to flow into the concentration chamber of the electrodeionization stack;
Adjusting the flow rate of the electrode water to a seventh predetermined flow rate value by a sixth valve provided in the electrode chamber inflow line for allowing the second permeated water to flow into the electrode chamber of the electrodeionization stack;
Checking whether the flow rate of the demineralized water is a fifth predetermined flow rate value,
When the flow rate of the desalted water is not the fifth predetermined flow rate value, the method further includes a step of adjusting the flow rate of the supplied water by the supply water valve so that the flow rate of the desalted water becomes the fifth predetermined flow rate value. The pure water manufacturing method of Claim 4.

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