JP2010172806A - Pure water production system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pure water production system where pure water stored in a pure water tank is constantly maintained with a desired high purity, and the pure water having high purity can be always fed to an external apparatus. <P>SOLUTION: The on/off control of a pure water device is performed (S1). The present water position is detected by a water position sensor 12 (S2), whether a timer counts a prescribed time or not is judged, and, when the prescribed time is passed, whether water position variation is caused or not is judged (S3→S4). Then, in the case water position variation is caused, the on/off control of the pure water device is performed (S4→S1), on the other hand, in the case water position variation is not caused, when the water position of a treatment water tank is less than the stop water position of a circulation pump, the pure water device is forcibly driven, and on the other hand, when the water position is more than the stop water position of the circulation pump, the circulation pump is driven, and at the point of time of lowering to the stop water position, the circulation pump is stopped, the pure water device is forcibly driven, and thereafter, the on/off control of the pure water device is performed, and the above treatments are repeated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pure water production system, and more specifically, stores pure water produced by a pure water device such as a membrane filtration device or an electric regenerative desalination device (hereinafter referred to as “EDI device”) in a pure water tank. The present invention also relates to a pure water production system for supplying pure water stored in the pure water tank to an external device such as a heat exchanger.

  Conventionally, pure water purified to high purity has been used for heat exchangers, cooling towers, boiler water, cleaning water for medical instruments, and the like.

  In this type of pure water production system, raw water such as ground water and well water is usually treated with a membrane filtration device such as a reverse osmosis membrane device (hereinafter referred to as “RO device”) or an EDI device, and pure water (treated water). And the generated pure water is stored in a treated water tank (pure water tank).

  For example, in Patent Document 1, as shown in FIG. 19, a treated water supply line 103 and a treated water supply line 103 are connected to a treated water outlet line 102 provided on the treated water outlet side of an EDI device 101 that deionizes the permeated water of the RO device 107. A treated water circulation line 104 is branched and connected, and a flow path switching means 105 for switching the treated water flow path to the treated water supply line 103 or the treated water circulation line 104 is installed, and the treated water tank 106 is disposed in the treated water supply line 102. And the treated water stored in the treated water tank 106 is sent to an external device, the EDI apparatus 101 is continuously operated, and the amount of treated water sent to the treated water supply line 102 is The treatment of the water to be treated by the electrodeionization method in which the control to send the treated water to the treated water supply line 102 and the control to send the treated water to the treated water circulation line 103 are performed. Methods have been proposed.

  That is, when the EDI device 101 is turned on / off according to the amount of water passing through the water supply line 108 connected to an external device, when the operation time of the EDI device 101 is short, the EDI device 101 is accommodated in a desalination chamber in the EDI device 101. The regeneration of the ion exchange resin is incomplete. Therefore, when the operation of the EDI apparatus 101 is resumed in this state, the operation is restarted in a state in which the ion exchange capacity of the ion exchange resin is lowered, which may cause a decrease in the purity of the treated water.

  Therefore, in Patent Document 1, while the EDI apparatus 101 is continuously operated, when the water level in the treated water tank 101 reaches a predetermined level, the treated water flow path is switched to the treated water circulation line 104 by the flow path switching means 105, The treated water is returned to the treated water supply line 109. As a result, the ion exchange resin accommodated in the desalination chamber in the EDI apparatus 101 can always be kept in a regenerated state, thereby preventing the purity of the treated water from being lowered.

Japanese Patent No. 3273718

However, in Patent Document 1, when the treated water tank 106 is in contact with the outside air, if the residence time of the treated water in the treated water tank 106 becomes longer due to, for example, a long stoppage of an external device connected to the water supply line 108, Atmospheric CO ₂ is dissolved in the treated water, or impurities such as metal ions are eluted from the inner wall of the treated water tank 106 and mounting parts such as a water level sensor arranged in the treated water tank 106. There is a risk of water quality degradation.

  The present invention has been made in view of such circumstances, and always maintains pure water stored in a pure water tank at a desired high purity, and constantly supplies such high purity pure water to an external device. It is an object of the present invention to provide a pure water production system capable of producing water.

  In order to achieve the above object, a pure water production system according to the present invention includes at least one or more pure water apparatuses that generate pure water, a pure water tank that stores pure water generated by the pure water apparatus, Water level detection means for detecting the water level of the pure water tank, circulation means for circulating the pure water in the pure water tank into the system, and judgment means for judging whether or not the water level has fluctuated within a predetermined time; And a drive means for driving the circulation means when the judgment means judges that the water level fluctuation has not occurred.

  Moreover, the pure water production system according to the present invention includes at least one or more pure water devices that generate pure water, a pure water tank that stores pure water generated by the pure water device, and the pure water tank. A flow rate output means for detecting the flow rate of pure water interposed between the external equipment and supplied to the external equipment, a circulation means for circulating pure water in the pure water tank in the system, and the flow rate detection means Determining means for determining whether or not the pure water flow rate has been detected within a predetermined time, and drive means for driving the circulation means when the determination means determines that the pure water flow rate has not been detected. It is characterized by having.

  Further, the pure water production system according to the present invention includes at least one or more pure water devices that generate pure water, a pure water tank that stores pure water generated by the pure water device, and an inside of the pure water tank. Water quality detection means for detecting the quality of the pure water, circulation means for circulating the pure water in the pure water tank in the system, and control for controlling the driving of the circulation means according to the detection result of the water quality detection means And a means.

  Furthermore, in the pure water production system of the present invention, the water quality detection means has specific resistance detection means for detecting a specific resistance of the pure water in the pure water tank, and the control means has the specific resistance It has a judging means for judging whether or not it is a predetermined value or less, and a driving means for driving the circulating means when the judging means judges that the specific resistance is not more than the predetermined value.

  Further, in the pure water production system of the present invention, the water quality detection means has electrical conductivity detection means for detecting the electrical conductivity of the pure water in the pure water tank, and the control means Determining means for determining whether or not conductivity is greater than or equal to a predetermined value; and drive means for driving the circulation means when the determining means determines that the electrical conductivity is equal to or greater than the predetermined value. It is characterized by being.

Further, in the pure water production system of the present invention, the water quality detection means includes a specific resistance detection means for detecting a specific resistance of the pure water in the pure water tank, and a CO ₂ concentration contained in the pure water. A CO ₂ concentration detecting means for detecting; and a pH detecting means for detecting a pH value of the pure water, wherein the control means is configured to perform comparison based on the detection results of the CO ₂ concentration detecting means and the pH detecting means. A specific resistance estimation means for estimating resistance; and a drive means for driving the circulation means when the detection result of the specific resistance detection means is smaller than the estimation result of the specific resistance estimation means. Yes.

Further, in the pure water production system of the present invention, the water quality detection means includes a specific resistance detection means for detecting the electrical conductivity of the pure water in the pure water tank, and a CO ₂ concentration contained in the pure water. CO ₂ concentration detection means for detecting the pH value, and pH detection means for detecting the pH value of the pure water. The control means is based on the detection results of the CO ₂ concentration detection means and the pH detection means. Electrical conductivity estimation means for estimating electrical conductivity; and drive means for driving the circulation means when the detection result of the electrical conductivity detection means is greater than the estimation result of the electrical conductivity estimation means. It is characterized by being.

  In the pure water production system of the present invention, the pure water device includes at least one of an EDI device, a membrane filtration device, and an ion exchange resin tower.

  Furthermore, the pure water production system of the present invention is characterized in that a treated water tank is provided upstream of the pure water device, and the circulating means is connected to the treated water tank.

  Further, in the pure water production system of the present invention, when a plurality of the pure water devices are provided, a water tank to be treated is provided upstream of the most upstream pure water device or between the pure water devices, and the circulation The means is connected to the water tank to be treated.

According to the pure water production system, at least one or more pure water devices (RO device, EDI device, ion exchange resin tower, etc.) that generate pure water and the pure water generated by the pure water device are stored. A pure water tank, a water level detecting means for detecting the water level of the pure water tank, a circulating means for circulating the pure water in the pure water tank into the system, and whether or not the water level has changed within a predetermined time. Since there is a judging means for judging and a driving means for driving the circulating means when the judging means judges that the water level fluctuation has not occurred, the water level in the pure water tank does not fluctuate for a predetermined time. In this case, the pure water in the pure water tank can be circulated in the system for reprocessing. Therefore, pure water does not stay in the pure water tank for a long time, so that CO _{2 in} the atmosphere dissolves in pure water or metal ions from parts attached to the inner wall of the pure water tank or the pure water tank. It is possible to suppress elution of impurities such as, and to always supply pure water having a desired high purity to an external device such as a heat exchanger.

Further, a flow rate detecting means is interposed between the pure water tank and the external device, and if the pure water flow rate is not detected for a predetermined time, it is determined that the water level has not changed for the predetermined time, and the circulating means is driven by the driving means. Therefore, the pure water in the pure water tank can be circulated in the system for reprocessing. That is, when the flow rate detection means is provided instead of the water level detection means, as described above, CO _{2 in} the atmosphere is dissolved in pure water or from the parts attached to the inner wall of the pure water tank or the pure water tank. Elution of impurities such as metal ions can be suppressed, and pure water having a desired high purity can be constantly supplied to an external device such as a heat exchanger.

Further, there is provided a specific resistance detecting means or an electric conductivity detecting means, and when the specific resistance is not more than a predetermined value or when the electric conductivity is not less than the predetermined value, it is judged that the quality of the pure water has deteriorated, and the circulating means by the driving means Therefore, the pure water in the pure water tank can be circulated in the system for reprocessing. That is, instead of detecting fluctuations in the water level and detecting the flow rate, by controlling the driving of the circulating means in accordance with the detected value of specific resistance or electrical conductivity, CO _{2 in} the atmosphere can be dissolved in pure water as described above. It is possible to suppress the elution of impurities such as metal ions from the inner wall of the pure water tank and the parts attached to the pure water tank, and always use the pure water having the desired high purity as an external device such as a heat exchanger. Can be supplied with water.

In addition to the specific resistance detection means or the electrical conductivity detection means, a CO ₂ concentration detection means and a pH detection means are provided to estimate the specific resistance or electrical conductivity based on the CO ₂ concentration or pH value, while the actual ratio By detecting the resistance or electrical conductivity, comparing the estimated value and the detected value, and controlling the driving of the circulating means according to the comparison result, it is possible to supply pure water of desired water quality to the external device. .

That is, when the specific resistance detection value is smaller than the specific resistance estimated value, or if the electrical conductivity detected value is greater than the electrical conductivity estimated value, a reduction factor of pure water purity is determined to be due to CO ₂ dissolution be able to. Therefore, in the case of water quality requirements that can be tolerated if CO _{2 is} dissolved, energy is saved by avoiding the wasteful circulation of pure water in the system, while the detected resistivity value is less than the estimated resistivity value. If the detected conductivity value is equal to or higher than the estimated conductivity value, it is determined that the water quality is reduced for reasons other than CO ₂ dissolution, such as elution of metal ions from a pure water tank. Can be circulated in the system, so that it is always possible to supply pure water having a desired water quality to an external device.

1 is a system configuration diagram showing an embodiment (first embodiment) of a pure water production system according to the present invention. It is the figure which showed the internal structure of the EDI apparatus typically. It is a block block diagram which shows the control system of the said pure water manufacturing system. It is a front view of the treated water tank for demonstrating a 1st water level setting pattern. It is a flowchart (1/2) which shows the control procedure in the 1st water level setting pattern of the said pure water manufacturing system. It is a flowchart (2/2) which shows the control procedure in the 1st water level setting pattern of the said pure water manufacturing system. It is a front view of the treated water tank for demonstrating a 2nd water level pattern. It is a flowchart (1/2) which shows the control procedure in the 2nd water level setting pattern of the said pure water manufacturing system. It is a flowchart (2/2) which shows the control procedure in the 2nd water level setting pattern of the said pure water manufacturing system. It is a system configuration figure showing a 2nd embodiment of a pure water manufacturing system concerning the present invention. It is a principal part flowchart of the control procedure of the said 2nd Embodiment. It is a system block diagram which shows 3rd Embodiment of the pure water manufacturing system which concerns on this invention. It is a principal part flowchart of the control procedure of the said 3rd Embodiment. It is a system configuration figure showing a 4th embodiment of a pure water manufacturing system concerning the present invention. It is a principal part flowchart of the control procedure of the said 4th Embodiment. It is a system configuration figure showing a 5th embodiment of a pure water manufacturing system concerning the present invention. It is a system configuration figure showing a 6th embodiment of a pure water manufacturing system concerning the present invention. It is a system configuration figure showing a 7th embodiment of a pure water manufacturing system concerning the present invention. 1 is a schematic system configuration diagram of a pure water production system described in Patent Document 1. FIG.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a system configuration diagram showing an embodiment of a pure water production system according to the present invention.

  The pure water production system includes a soft water device 2 that softens raw water from the raw water supply line 1 to generate treated water, a treated water tank 3 that stores treated water generated by the soft water device 2, and A pure water device 5 that generates pure water by treating the water to be treated supplied from the water to be treated line 4, and treated water that stores the pure water produced by the pure water device 5 via the treated water line 6. And a tank (pure water tank) 7.

  The treated water tank 7 is connected to an external device such as a cooling / heating device via a water supply line 8 and supplies pure water to the external device, while the pure water in the treated water tank 7 is covered via a circulating water line 9. It is configured to be able to return to the treated water tank 3. That is, the circulating water line 9 is provided with a circulation valve 10 and a circulation pump (circulation means) 11, and pure water in the treated water tank 7 is returned to the treated water tank 3 as necessary.

  In addition, a pressure detection type water level sensor (water level detection means) 12 is provided below the treated water tank 7 to detect the water head in the treated water tank 7 and transmit the detection signal to a control unit described later.

  The water softener 2 contains a sodium-type cation exchange resin (not shown) in an ion exchange resin tower, and a saturated saline solution is placed in a salt water tank (not shown) attached to the ion exchange resin tower. Is stored. In this water softener 2, raw water is supplied from the raw water supply line 1 in the water flow mode. Then, the hardness components contained in the raw water, that is, calcium ions and magnesium ions are ion-exchanged with sodium ions of the cation exchange resin to be removed, softened, and become treated water stored in the treated water tank 3. The Moreover, when the exchange capacity of the cation exchange resin of the water softener 2 is saturated, the water softener 2 is switched from the water flow mode to the regeneration mode, and saturated saline is supplied from the salt water tank, whereby the cation exchange resin. Is played. When the regeneration process is completed, the water supply mode is entered again, and raw water can be supplied.

  Moreover, the pure water apparatus 5 is comprised by the RO apparatus 13 and the EDI apparatus 14 in this Embodiment.

  The RO device 13 includes, for example, an RO module 15 including an RO membrane element (hereinafter referred to as “RO membrane”) 15 a wound in a spiral shape, and a pressure pump 16. The RO module 15 is separated into a primary side to which treated water is supplied and a secondary side that outputs permeated water that has passed through the RO membrane 15a. Furthermore, the RO device 13 includes an RO circulating water line 17 that circulates a part of the concentrated water that has not permeated the RO membrane 15a to the raw water side, and a drain line 18 that drains the remainder of the concentrated water outside the system. It is connected. Specifically, the RO circulating water line 17 is branched from the middle of the drainage line 18 and connected to the upstream side of the pressurizing pump 16, and a constant flow control valve (not shown) is connected to the RO circulating water line 17. ) Is interposed, and part of the concentrated water is combined with the water to be treated from the water tank 3 to be treated and supplied to the RO module 15. A drain valve 19 is interposed in the drain line 18.

In the RO device 13 configured as described above, when the pressurization pump 16 is driven and a high pressure higher than the osmotic pressure is applied to the RO membrane 15a from the primary side, dissolved salts and silica (SiO ₂ ) are removed. Purified permeate flows out to the secondary side, thereby producing treated water. A part of the concentrated water that has not permeated the RO membrane 15 a is returned to the upstream side of the pressurizing pump 16 through the RO circulating water line 17, and the rest is drained from the drain valve 19.

  Further, the EDI device 14 has an EDI device body 20 for processing the permeated water supplied from the RO device 13 via the permeate water line 21, and a water feed pump 22 is interposed in the permeate water line 21. .

  Specifically, as shown in FIG. 2, the EDI apparatus main body 20 includes an anode 23 and a cathode 24, and an anion exchange membrane 25 and a cation exchange membrane 26 are interposed between the anode 23 and the cathode 24. Many rows are arranged alternately. An anode chamber 27 is formed by the anode 23 and the anion exchange membrane 25 adjacent to the anode 23, and a cathode chamber 28 is formed by the cathode 24 and the cation exchange membrane 26 adjacent to the cathode 24. 25 and the cation exchange membrane 26, a desalting chamber 29 and a concentration chamber 30 are alternately formed from the left side in the figure, and each desalting chamber 29 is composed of a mixture of a cation exchanger and an anion exchanger. An ion exchanger 31 is filled. The desalting chamber 29 is connected to the treated water line 6, while the anode chamber 27 and the cathode chamber 28 are connected to the electrode water line 32, and the electrode water is drained outside the system through the drain valve 33. Further, the concentrating chamber 30 is connected to a concentrated water line 34, a part of the concentrated water is collected in the permeated water line 21, and the remaining part is drained outside the system through a drain valve 35. The concentrated water from the concentrated water line 34 has higher purity than the water to be treated, so that it can be combined with the water tank 3 to be treated or the water line 4 to be collected to collect the entire amount.

  In the EDI apparatus 14 configured as described above, when a DC voltage is applied between the anode 23 and the cathode 24, ionic components in the permeated water that has entered the desalting chamber 29 have a potential on the surface of the ion exchanger 31. Move in the direction. That is, the anion passes through the anion exchange membrane 25 and moves to the anode chamber 27 or the concentration chamber 30, while the cation passes through the cation exchange membrane 26 to the cathode chamber 28 or the concentration chamber 30, Concentrated water containing these ionic components is discharged out of the system via the electrode water line 32 or the concentrated water line 34.

  In FIG. 1, the electrode water in the anode chamber 27 or the cathode chamber 28 is drained from the electrode water line 32, but the purity is higher than the water to be treated, like concentrated water. Or you may comprise so that the whole quantity may join the to-be-treated water tank 3 or the to-be-treated water line 4. FIG.

  In this way, the permeated water containing a small amount of ionic components supplied to the desalting chamber 29 becomes deionized high-purity pure water and is supplied from the treated water line 6 to the treated water tank 7.

  FIG. 3 is a block diagram showing the control system of the pure water production system.

  The control unit 36 performs interface operations with the water softener 2, the RO device 13, and the EDI device 14, receives an electrical signal from the water level sensor 12, and transmits a drive signal to the circulation valve 10 and the circulation pump 11. An input / output unit 37, a ROM 38 storing a predetermined calculation program, a RAM 39 for temporarily storing calculation results and used as a work area, and a CPU 40 incorporating a timer 40a for controlling the entire system. ing.

  In the pure water production system, the RO device 13 and the EDI device 14 are driven in conjunction, and when these pure water devices 5 are driven, pure water is supplied to the treated water tank 7 via the treated water line 6. In addition, when the water level of the treated water tank 7 reaches a predetermined upper limit water level LH due to, for example, stoppage of water supply to the water supply line 8, the drive of the pure water device 5 is stopped.

  In the present embodiment, the control unit 36 determines whether or not the water level in the treated water tank 7 has fluctuated within a predetermined time, and the determination means determines that the water level has not changed. Drive means for driving the circulation means.

  FIG. 4 is a diagram showing an example of the water level pattern (first water level setting pattern) of the treated water tank 7, and the stop position L of the circulation pump 11 is set higher than the drive water level LL of the pure water device 5.

  5 and 6 are flowcharts showing a control procedure in the first water level setting pattern.

  In step S1, on / off control of the pure water device 5 is performed. That is, the deionized water device 5 is turned off when the water level of the treated water tank 7 reaches the upper limit water level LH, and the water level is changed to the driving water level LL of the deionized water device 5 due to the outflow of pure water to the water supply line 8 or the circulating water line. Turns on when reaching.

  Next, in step S2, the current water level is detected by the water level sensor 12, and in step S3, it is determined whether or not the timer 40a has counted a predetermined time (for example, 1 hour). If the answer to step S3 is negative (No), the process waits for a predetermined time to elapse. If the predetermined time elapses, the process proceeds to step S4 to determine whether or not a water level change has occurred.

  And when the answer is affirmative (Yes), it returns to step S1, performs on-off control of the pure water apparatus 5, and repeats the process of the said step S2-step S4 after that.

  On the other hand, if the answer to step S4 is negative (No) and it is determined that the water level does not fluctuate, the process proceeds to step S5 in FIG. 6 to determine whether the water level is equal to or higher than the stop water level L of the circulation pump 11. .

  And when the answer is affirmative (Yes), it progresses to step S6, the circulation pump 11 is driven, and the pure water in the treated water tank 7 is recirculated to the treated water tank 3.

  Next, in step S7, it is determined whether or not the water level in the processing tank 7 has dropped to the stop water level L of the circulation pump 11. When the answer is negative (No), the process waits for the water level of the processing tank 7 to drop to the stop water level L. When the water level drops to the stop water level L, the process proceeds to step S8 and the circulation pump 11 Then, the process proceeds to step S9 to forcibly drive the pure water device 5.

  On the other hand, when the answer to step S5 is negative (No), that is, when the water level of the processing tank 7 is lower than the stop water level L of the circulation pump 11, the process proceeds to step S9 to forcibly drive the pure water device 5.

  Thus, immediately after the circulation pump 11 is stopped and when the water level in the treated water tank 7 is less than the stop water level L of the circulation pump 11 even if there is no fluctuation in the water level, the pure water device 5 is forcibly driven. This makes it possible to supply pure water of desired water quality to the external device while maintaining high purity even when a water supply request is generated from the external device during this period.

  Then, it returns to step S1 of FIG. 5, performs on-off control of the pure water apparatus 5, and repeats the process mentioned above.

As described above, in this embodiment, when the water level of the treated water tank 7 does not change even after a predetermined time has elapsed, the circulating pump 11 is driven to forcibly return to the treated water tank 3 for reprocessing. Therefore, it is possible to prevent the deionized water from staying in the treated water tank 7 for a long time. Therefore, it is possible to avoid as much as possible that CO ₂ in the atmosphere is dissolved in pure water, or metal ions are eluted from the inner wall of the treated water tank 7 and mixed into the pure water. And it becomes possible to always maintain the pure water in the treated water tank 7 with high purity, and it becomes possible to always supply pure water having a desired water quality to an external device.

  FIG. 7 is a diagram showing a second water level setting pattern of the treated water tank 7, in which the stop position L of the circulation pump 11 is set lower than the drive water level LL of the pure water device 5.

  8 and 9 are flowcharts showing a control procedure in the second water level setting pattern.

  In step S11, on / off control of the deionized water device 5 is performed as described above. In step S12, the current water level is detected by the water level sensor 12, and whether or not a predetermined time (for example, 1 hour) has elapsed in step S13. Determine whether. If the answer to step S13 is negative (No), the process waits for a predetermined time to elapse. If the predetermined time elapses, the process proceeds to step S14 to determine whether the water level has changed.

  If the answer is negative (No) and the water level does not fluctuate, the process proceeds to step S15 in FIG. 9, the circulation valve 10 is opened and the circulation pump 11 is driven, and the process is continued in step S16. It is determined whether or not the water tank water level has dropped to the driving water level LL of the pure water device 5.

  When the answer is negative (No), the process waits for the treated water tank water level to drop to the driving water level LL of the pure water device 5, and when the water level drops to the driving water level LL, the process proceeds to step S17 and goes to the pure water device. 5 is driven, and the process proceeds to step S18.

  On the other hand, if the answer to step S14 of FIG. 8 is affirmative (Yes), that is, if the water level fluctuates during a predetermined time, the process immediately proceeds to step S18.

  Next, in step S <b> 18, it is determined whether or not the treated water tank water level has decreased to the stop water level L of the circulation pump 11. If the answer is negative (No), that is, if the water level has not dropped to the stop water level L of the circulation pump 11, the process returns to step S11, the on / off control of the pure water device 5 is performed, and the above-described processing is repeated. .

  On the other hand, if the answer to step S18 is affirmative (Yes), the process proceeds to step S19 to determine whether or not the circulation pump 11 is in operation. If the answer is negative (No), it is determined that the water level of the treated water tank has dropped due to a water supply request from an external device, and the process returns to step S11 to repeat the above-described processing.

  If the answer to step S19 is affirmative (Yes), since the pure water device 5 is driven in step S17, the process proceeds to step S20, the drive of the circulation pump 11 is stopped, and the process returns to step S11. The above process is repeated.

Thus, also in the case of the second water level setting pattern, when the water level of the treated water tank 7 has not changed for a predetermined time, the circulating pump 11 is driven to force the water to be treated to be returned to the treated water tank 3 for reprocessing. Therefore, it is possible to prevent the deionized water from staying in the treated water tank 7 for a long time. Accordingly, as in the case of the first water level setting pattern, CO _{2 in} the atmosphere is dissolved in pure water, or metal ions are eluted from the inner wall of the treated water tank 7 and mixed in the pure water as much as possible. Accordingly, the pure water in the treated water tank 7 can always be maintained at a high purity, and the pure water having a desired water quality can be always supplied to the external device.

  Next, various modifications will be described in detail for the case where the drive water level LL of the pure water device 5 and the stop water level L of the circulation pump 11 are the first water level setting pattern. The drive water level LL and the stop water level L are The same applies to the second water level setting pattern.

  FIG. 10 is a system configuration diagram showing a second embodiment of the pure water production system according to the present invention.

  In the second embodiment, a flow meter (flow rate detection means) 41 is interposed in the water supply line 8, and a detection signal of the flow meter 41 is transmitted to the control unit 36, and the detection result of the flow meter 41 is displayed. Accordingly, the driving of the circulation pump 11 is controlled.

  FIG. 11 is a main part flowchart of the control procedure of the second embodiment.

  In step S21, on / off control of the deionized water device 5 is performed as in FIG. 5 of the first embodiment. Next, in step S22, it is determined whether or not the timer 40a has counted a predetermined time (for example, 1 hour). If the answer to step S22 is negative (No), the process waits for a predetermined time to elapse. If the predetermined time elapses, the process proceeds to step S23 to determine whether the flow meter 41 has detected a flow rate.

  If the answer is affirmative (Yes), that is, if the flow rate is detected by the flow meter 41, it is determined that the pure water in the treated water tank 7 is supplied to the external device via the water supply line 8. Returning to step S21, the above-described processing is repeated.

  On the other hand, if the answer to step S23 is negative (No), that is, if the flow rate is not detected by the flow meter 41, pure water is not supplied to the external device, and the water level does not change for a predetermined time. The process proceeds to step S5 in FIG. 6, and thereafter, the same processing as in the first embodiment is executed. That is, when the water level of the treated water tank 7 is less than the stop water level L of the circulation pump 11, the pure water device 5 is forcibly driven (S5 → S9), while the water level is equal to or higher than the stop water level L of the circulation pump 11. In this case, the circulation pump 11 is driven, the circulation pump is stopped when the water level drops to the stop water level L, and the pure water device 5 is forcibly driven (S5 → S6 → S7 → S8 → S9), and then step S21. Return to.

As described above, in the second embodiment, when the flow rate is not detected for a predetermined time by the flow meter 41, it is determined that the water level of the treated water tank 7 has not fluctuated for a predetermined time, and the circulation pump 11 is driven. Since the reprocessing is performed by forcibly returning to the water tank 3 to be treated, it is possible to prevent the deionized water from staying in the water tank 7 for a long time. Therefore, as in the first embodiment, it is avoided that CO _{2 in} the atmosphere is dissolved in pure water or metal ions are eluted from the inner wall of the treated water tank 7 and mixed in the pure water. As a result, the pure water in the treated water tank 7 can always be maintained at a high purity, and the pure water having a desired water quality can be constantly supplied to the external device.

  FIG. 12 is a system configuration diagram showing a third embodiment of the pure water production system according to the present invention.

  In the third embodiment, a specific resistance meter (specific resistance detection means) 42 is attached to the treated water tank 7, and a detection signal of the specific resistance meter 42 is transmitted to the control unit 36 to detect the specific resistance meter 42. The driving of the circulation pump 11 is controlled according to the result.

  FIG. 13 is a main part flowchart of the control procedure of the third embodiment.

  In step S31, the on / off control of the pure water apparatus 5 is performed as in FIG. 5 of the first embodiment. Next, in step S32, it is determined whether or not the specific resistance detected by the specific resistance meter 42 is a predetermined value (for example, 10 MΩ · cm) or less. If the answer to step S32 is negative (No), it is determined that the pure water in the treated water tank 7 maintains the desired purity, and the process returns to step S31 to perform on / off control of the pure water device 5.

  On the other hand, if the answer to step S32 is affirmative (Yes), it is determined that the purity of the pure water in the treated water tank 7 is lowered, and the process proceeds to step S5 in FIG. 6, and the same as in the first embodiment. Execute the process. That is, when the water level of the treated water tank 7 is less than the stop water level L of the circulation pump 11, the pure water device 5 is forcibly driven (S5 → S9), while the treated water tank water level is the stop water level L of the circulation pump 11. In the above case, the circulation pump 11 is driven, the circulation pump is stopped when the water level drops to the stop water level L, the pure water device 5 is forcibly driven (S5 → S6 → S7 → S8 → S9), and then Return to step S21.

As described above, in the third embodiment, when the specific resistance is equal to or lower than the predetermined value, it is determined that the purity of pure water has decreased to the predetermined value or lower, the circulation pump 11 is driven, and the water tank 3 is treated. Since the reprocessing is performed by forcibly refluxing, it is possible to prevent the deionized water from staying in the treated water tank 7 for a long time. Therefore, as in the first and second embodiments, it is as much as possible that CO _{2 in} the atmosphere is dissolved in pure water or metal ions are eluted from the inner wall of the treated water tank 7 and mixed into the pure water. This makes it possible to always maintain the pure water in the treated water tank 7 with a high purity, and to always supply the pure water having a desired high purity to an external device.

  FIG. 14 is a system configuration diagram showing a fourth embodiment of the pure water production system according to the present invention.

In the fourth embodiment, in addition to the resistivity meter 42, a CO ₂ sensor (CO ₂ concentration detection means) 43 and a pH sensor (pH detection means) 44 are attached to the treated water tank 7, and these resistivity meters 42, The detection signals of the CO ₂ sensor 43 and the pH sensor 44 are transmitted to the control unit 36, and the drive of the circulation pump 11 is controlled according to these detection results.

That is, in the fourth embodiment, when the decrease in the purity of pure water is caused only by the dissolution of CO ₂ , the factor of the decrease in purity is estimated in the case of a water quality requirement that is within the allowable range, and the treated water is The circulation of pure water in the tank 7 to the treated water tank 3 is controlled.

  FIG. 15 is a main part flowchart of the control procedure of the fourth embodiment.

  In step S41, on / off control of the pure water apparatus 5 is performed as in FIG. 5 of the first embodiment.

Then, in step S42, detects the CO ₂ concentration and pH value in the CO ₂ sensor 43 and the pH sensor 44, these detected CO ₂ value, HCO ₃ based on the detected pH value ^- to estimate the ^- concentration [HCO _3].

That is, when CO ₂ in the atmosphere is dissolved in pure water, an equilibrium reaction represented by the chemical formula (A) occurs.

  Therefore, the equilibrium constant K is expressed by Equation (1).

Therefore, HCO ₃ ^- concentration [HCO ₃ ^-] is represented by the equation (2).

Then, pH, since a pH = -log ^{[H +],} HCO ₃ ^- concentration [HCO ₃ ^-] is represented by the CO ₂ concentration [CO _2] and pH values is as in Equation (3).

Here, the equilibrium constant K, since it is a constant inherent (1.0 × 10 ^6.4 at25 ℃) to the reaction system, HCO from the detected CO ₂ value and the detected pH value ₃ ^- concentration [HCO ₃ ^-] to estimate the Can do.

Thus HCO from the detected CO ₂ value and the detected pH value based on at step S42 Equation (3) ₃ ^- to estimate the ^- concentration [HCO _3].

In step S43, the specific resistance ρ is estimated. That, HCO _3, which is estimated in step S42 ^- the HCO ₃ ^- concentration [HCO _3] ^- Estimate electric conductivity κ because extreme molar conductivity ^{_{Λ 0 (= 44.5S · cm 2}} / mol) and of the The specific resistance ρ1 (= 1 / κ) is calculated from the electrical conductivity κ.

In step S44, the actual resistivity ρ2 is detected by the resistivity meter 42, and in the subsequent step S45, the estimated value (ρ1) and the detected value (ρ2) are compared. If the detected value is greater than or equal to the estimated value, it is determined that the decrease in purity of pure water is due only to CO ₂ dissolution, and the process returns to step S41 without performing circulation control to the treated water tank 3 with pure water. Repeat the process.

On the other hand, if the answer to step S45 is affirmative (Yes), that is, if the detected value is less than the estimated value, factors other than CO ₂ dissolution, for example, the inner wall of the treated water tank 7 or the parts attached to the treated water tank 7 It is determined that the purity of pure water is reduced due to elution of metal ions (water level sensor 12, specific resistance meter 42, CO ₂ sensor 43, pH sensor 44, etc.), and the process proceeds to step S5 in FIG. Control processing similar to that in the embodiment is executed. That is, when the water level of the treated water tank 7 is less than the stop water level L of the circulation pump 11, the pure water device 5 is forcibly driven (S5 → S9), while the water level is equal to or higher than the stop water level L of the circulation pump 11. In this case, the circulation pump 11 is driven, the circulation pump is stopped when the water level drops to the stop water level L, and the pure water device 5 is forcibly driven (S5 → S6 → S7 → S8 → S9), and then step S41. Return to.

As described above, in the fourth embodiment, when the specific resistance detection value is less than the specific resistance estimation value, the circulation pump 11 is driven and the water tank 3 to be treated is driven as in the first to third embodiments. Reprocessing is performed by forcibly refluxing, but if the specific resistance detection value is equal to or greater than the specific resistance estimation value, it is determined that the purity reduction of pure water is caused only by CO ₂ dissolution, and the driving of the circulation pump 11 is stopped. Therefore, the circulation control according to the required quality of the water quality can be performed. That is, unnecessary driving of the circulation pump 11 can be eliminated to save energy, and pure water having a desired water quality can be constantly supplied to the external device.

  Furthermore, in the said embodiment, although the pure water apparatus 5 is comprised by the RO apparatus 13 and the EDI apparatus 14, it cannot be overemphasized that it is not limited to these.

  FIG. 16 is a system configuration diagram showing a fifth embodiment of the pure water production system according to the present invention.

  In the fifth embodiment, the deionized water device 5 ′ is composed of a double bed type or mixed bed type ion exchange resin tower 45 and an EDI device 14. In other words, an ion exchange resin tower 45 is provided in place of the RO device 12, and in this case as well, by performing any of the controls described in the first to fourth embodiments, the pure water having a desired water quality is always obtained. It becomes possible to supply water to an external device.

  As described above, various types of pure water devices can be used. For example, in each of the above embodiments, the RO device 12 is used as the membrane filtration device. However, the same applies when a nanofiltration membrane is used instead of the RO membrane 15a. It goes without saying that the same applies when using a pure water apparatus.

  Moreover, the pure water apparatus should just be equipped with at least 1 or more, and single or several various combinations are possible.

  FIG. 17 is a system configuration diagram showing a sixth embodiment of the pure water production system according to the present invention.

  In the sixth embodiment, the treated water tank 3 is interposed between the RO device 12 and the EDI device 14.

  That is, in the first to fourth embodiments, the treated water tank 3 is provided on the upstream side of the uppermost stream of the two pure water devices (RO device 12 and EDI device 14). In the embodiment, the water tank 3 to be treated is interposed between two pure water apparatuses.

  As long as the pure water in the treated water tank 7 can be reprocessed in this way, it is not necessarily required to be upstream of the most upstream pure water device, and the pure water is returned to the upstream side of at least one pure water device. I can do it.

  FIG. 18 is a system configuration diagram showing a seventh embodiment of the pure water production system according to the present invention.

  In the seventh embodiment, pure water is recirculated to the treated water line 7 without providing a treated water tank. That is, the circulating water line 9 ′ is provided with a branch line 46 in the middle, and a drain valve 47 is interposed in the branch line 46. For example, when the circulating pump 11 is driven while the pure water device 5 is stopped, the drain valve 47 is opened to drain water, and when the circulating pump 11 is driven while the pure water device 5 is driven, The valve 47 is closed to return to the water line 7 to be treated, thereby controlling the circulation of pure water.

  The present invention can be further modified in various ways. Although the specific resistance meter 42 is used in the third and fourth embodiments, an electrical conductivity sensor (electric conductivity detection means) may be provided in place of the specific resistance meter 42. In this case, since the electric conductivity is the reciprocal of the specific resistance, for example, in step S32 of FIG. 13 in the third embodiment, the circulation pump 11 is driven when the specific resistance is equal to or less than a predetermined value. When the conductivity sensor is used, the circulation pump 11 may be driven when the electrical conductivity is equal to or higher than a predetermined value. Similarly, in step S45 of FIG. 15 in the fourth embodiment, the circulation pump 11 is driven when the detected specific resistance value is less than the estimated specific resistance value. However, when the electrical conductivity sensor is used, the electrical conduction is performed. What is necessary is just to drive the circulation pump 11 when a rate detection value exceeds an electrical conductivity estimated value.

  INDUSTRIAL APPLICABILITY The present invention is useful for a system that always maintains pure water in a treated water tank at a desired purity and supplies pure water having a desired water quality to an external device such as a cooling / heating device.

5 Pure water equipment 7 Treated water tank (pure water tank)
11 Circulation pump (circulation means)
12 Water level sensor (water level detection means)
13 RO device 14 EDI device 36 Control unit (determination means, drive means, drive control means)
41 Flow meter (flow rate detection means)
42 Resistivity meter (resistivity detection means)
43 CO ₂ sensor (CO ₂ detection means)
44 pH sensor (pH detection means)
45 Ion exchange resin tower

Claims (10)

  At least one or more pure water apparatuses that generate pure water, a pure water tank that stores pure water generated by the pure water apparatus, a water level detection unit that detects a water level of the pure water tank, and the pure water A circulating means for circulating pure water in the tank into the system; a judging means for judging whether or not the water level has fluctuated within a predetermined time; and when the judging means determines that the water level has not fluctuated. A pure water production system comprising drive means for driving the circulation means.   At least one or more pure water devices that generate pure water, a pure water tank that stores pure water generated by the pure water device, and the external device interposed between the pure water tank and an external device. A flow rate detecting means for detecting a flow rate of pure water supplied to the device, a circulating means for circulating pure water in the pure water tank into the system, and the flow rate detecting means detected the pure water flow rate within a predetermined time. A pure water production comprising: a judging means for judging whether or not the pure water flow rate is not detected by the judging means; and a driving means for driving the circulating means system.   At least one or more pure water devices that generate pure water, a pure water tank that stores pure water generated by the pure water device, and water quality detection means that detects the quality of pure water in the pure water tank A pure means for circulating pure water in the pure water tank into the system; and a control means for controlling the driving of the circulating means in accordance with the detection result of the water quality detecting means. Water production system. The water quality detection means has a specific resistance detection means for detecting a specific resistance of the pure water in the pure water tank,
The control means includes a judging means for judging whether or not the specific resistance is not more than a predetermined value, and a driving means for driving the circulation means when the judging means judges that the specific resistance is not more than the predetermined value. The pure water production system according to claim 3, wherein the pure water production system is provided. The water quality detection means has electrical conductivity detection means for detecting electrical conductivity of the pure water in the pure water tank,
The control means determines whether or not the electrical conductivity is greater than or equal to a predetermined value, and drives the circulation means when the determination means determines that the electrical conductivity is greater than or equal to the predetermined value. The pure water manufacturing system according to claim 3, further comprising a driving unit. The water quality detection means, said a specific resistance detecting means, wherein detecting the resistivity of the pure water in the pure water tank, a CO ₂ concentration detection means for detecting a CO ₂ concentration contained in the pure water, the pure PH detecting means for detecting the pH value of water,
The control means includes a specific resistance estimation means for estimating specific resistance based on detection results of the CO ₂ concentration detection means and the pH detection means, and a detection result of the specific resistance detection means is estimated by the specific resistance estimation means. 4. The pure water production system according to claim 3, further comprising a drive unit that drives the circulation unit when the result is smaller than the result. The water quality detection means, the electrical conductivity detecting unit operable to detect the electrical conductivity of the pure water in the pure water tank, a CO ₂ concentration detection means for detecting a CO ₂ concentration contained in the pure water, PH detecting means for detecting the pH value of the pure water,
The control means includes an electrical conductivity estimation means for estimating electrical conductivity based on the detection results of the CO ₂ concentration detection means and the pH detection means, and the detection result of the electrical conductivity detection means indicates the electrical conductivity. 4. The pure water production system according to claim 3, further comprising a drive unit that drives the circulation unit when the estimation result is larger than an estimation result of the estimation unit.   The pure water apparatus according to any one of claims 1 to 7, wherein the pure water apparatus includes at least one of an electric regenerative desalting apparatus, a membrane filtration apparatus, and an ion exchange resin tower. Water production system.   The pure water according to any one of claims 1 to 8, wherein a water tank to be treated is provided upstream of the pure water device, and the circulation means is connected to the water tank to be treated. Manufacturing system.   In the case where a plurality of the pure water devices are provided, a treated water tank is provided upstream of the most upstream pure water device or between the pure water devices, and the circulating means is connected to the treated water tank. The pure water production system according to any one of claims 1 to 8, wherein the pure water production system is provided.

Images