JP2020020727A - Residual chlorine detector and residual chlorine detection method - Google Patents

Abstract

To provide a residual chlorine detector and a residual chlorine detection method, capable of detecting free residual chlorine with higher accuracy than before.SOLUTION: In a residual chlorine detector 10 and a residual chlorine detection method, a pair of electrodes 16A, 16B is immersed into tap water after elimination process of free residual chlorine to detect a first voltage. A voltage component consisting of inclusion other than free residual chlorine is subtracted from a second voltage detected by immersion of the pair of electrodes 16A, 16B into untreated tap water based on the first voltage to obtain a difference voltage.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a residual chlorine detection device and a residual chlorine detection method for detecting free residual chlorine in tap water.

  Conventionally, as this type of residual chlorine detection method, there is known a method of immersing a pair of electrodes having different ionization tendency in tap water and detecting free residual chlorine based on a voltage generated between the electrodes (for example, Patent Document 1).

JP-A-2006-114376 (paragraph [0008])

  By the way, in the above-mentioned conventional residual chlorine detection method, a technology has been developed in which the detection accuracy is increased by making it less susceptible to inclusions other than free residual chlorine in tap water. However, since the effect is not sufficient, there is a need for the development of a technology capable of detecting free residual chlorine with higher accuracy than before.

  The invention of claim 1 made in order to solve the above-mentioned problem is a residual chlorine detecting device for detecting free residual chlorine in tap water, which removes the free residual chlorine from tap water discharged from a water pipe. A removal processing unit to be performed, a pair of electrodes having different ionization tendencies, a first voltage generated between the pair of electrodes in a state where the pair of electrodes is immersed in the treated tap water after the removal processing, and the removal. A measuring unit that detects a second voltage generated between the pair of electrodes in a state where the pair of electrodes is immersed in untreated tap water that has not been treated; and a measuring unit that detects the free residual chlorine in the tap water from the second voltage. And a difference calculation unit that obtains a difference voltage by subtracting a voltage component due to other components based on the first voltage.

  The invention according to claim 2 is characterized in that the removal processing section has a storage section in which tap water discharged from the water pipe is stored for a predetermined reference time or more, and the removal processing is performed by storing the tap water for the reference time or more. 2. The residual chlorine detection device according to claim 1, wherein the first voltage and the second voltage are detected in a state where the pair of electrodes are fixed to the storage unit.

  The invention according to claim 3 is the residual chlorine detection according to claim 2, wherein the difference calculation unit obtains the difference voltage from the second voltage and a first voltage detected immediately before the detection of the second voltage. Device.

  The invention according to claim 4 is a water outlet that drains tap water from the reservoir and is opened and closed by a drain valve, and a water inlet that supplies tap water to the reservoir and is opened and closed by a valve for water supply. And a valve control unit that controls the drainage valve and the water supply valve so that the storage unit is always maintained substantially full, including when the treated tap water is replaced with the untreated tap water. The residual chlorine detection device according to claim 2 or 3, further comprising:

  The invention according to claim 5 is characterized in that the amount of water supplied from the water supply port when the water supply valve is fully opened is larger than the amount of water discharged from the water discharge port when the drainage valve is fully opened, and the valve control is performed. 5. The residual chlorine detection device according to claim 4, wherein when the inside of the storage section is replaced with the untreated tap water from the treated tap water, both the drain valve and the water supply valve are fully opened. 6.

  The invention of claim 6 is the residual chlorine detection device according to any one of claims 2 to 5, further comprising a stirrer for stirring tap water in the storage unit.

  The invention according to claim 7 is the residual chlorine detection device according to any one of claims 2 to 6, wherein an upper surface of the storage section is open.

  The invention of claim 8 is a residual chlorine detection method for detecting free residual chlorine in tap water, wherein the treated tap water which has been subjected to the removal treatment of free residual chlorine from tap water discharged from a water pipe is ionized. Immerses a pair of electrodes different from each other to detect a first voltage generated between the electrodes, and immerses the pair of electrodes in untreated tap water that has not been subjected to the removal treatment to generate a voltage between the electrodes. Detecting a second voltage, subtracting a voltage component due to a substance other than the free residual chlorine of tap water based on the first voltage from the second voltage to obtain a differential voltage, and using the differential voltage This is a residual chlorine detection method for detecting free residual chlorine.

  The invention according to claim 9 performs the removing process by storing tap water discharged from the water pipe in a storage unit for a predetermined reference time or more, and fixes the pair of electrodes to the storage unit. The residual chlorine detection method according to claim 8, wherein the first voltage and the second voltage are detected by the method.

  A tenth aspect of the present invention is the residual chlorine detecting method according to the ninth aspect, wherein the difference voltage is obtained from the second voltage and the first voltage detected immediately before the detection of the second voltage.

  The invention according to claim 11 is the residual chlorine detection method according to claim 9 or 10, wherein the storage section is always kept substantially full, including when the treated tap water is replaced with the untreated tap water.

  According to the first and eighth aspects of the present invention, the first voltage is detected by immersing the pair of electrodes in tap water having been subjected to the removal treatment of free residual chlorine. Then, a voltage component due to substances other than free residual chlorine is subtracted from the second voltage detected by immersing the pair of electrodes in untreated tap water based on the first voltage to obtain a difference voltage. By utilizing the method, free residual chlorine can be detected with higher accuracy than before.

  According to the second and ninth aspects of the present invention, since the pair of electrodes is fixed to the storage section in which the treated tap water and the untreated tap water are stored, it is easy to make the detection conditions of the first voltage and the second voltage uniform. This also makes it possible to detect free residual chlorine with high accuracy.

  The difference voltage may be obtained from the second voltage and the first voltage detected immediately after the second voltage, or the second voltage and the first voltage detected immediately before the second voltage as in the inventions of claims 3 and 10. And may be obtained from In the former case, a removal time for removing free residual chlorine is required between the detection of the first voltage and the second voltage, and in the latter case, replacement time of tap water is required. Normally, the replacement time can be shortened as compared with the removal time. Therefore, according to the third and tenth aspects of the present invention, it becomes easy to make the detection conditions of the first voltage and the second voltage uniform.

  Electrodes have different surface states depending on whether they are in contact with air or water, which can be a disturbance factor for voltage detection. On the other hand, according to the inventions of claims 4 and 11, since the storage section is always kept substantially full, including when the treated tap water is replaced with untreated tap water, disturbance of the first voltage and the second voltage is reduced. It is possible to perform suppressed detection.

  According to the configuration of claim 5, the storage section can be maintained full and the treated tap water can be replaced with untreated tap water simply by fully opening both the drain valve and the water supply valve.

  According to the configuration of claim 6, the tap water in the storage unit is stirred by the stirrer, so that the removal of the residual chlorine detecting device can be promoted. When detecting the voltage, it is preferable to stop the stirrer to stop the flow in the tap water.

  According to the configuration of claim 7, since the upper surface of the storage section is open, the stored tap water comes into contact with air to facilitate removal of free residual chlorine.

Schematic diagram of the residual chlorine detector of the first embodiment Flow chart of control program Flow chart of control program Conceptual diagram of the residual chlorine detector of the second embodiment Conceptual diagram of the residual chlorine detector of the third embodiment

[First Embodiment]
Hereinafter, embodiments of the residual chlorine detection device 10 and the residual chlorine detection method shown in FIGS. 1 to 3 will be described. FIG. 1 conceptually shows a residual chlorine detection device 10 of the present embodiment. The residual chlorine detection device 10 includes a storage unit 11 having a tank structure with an open upper surface. The outlet of the water pipe 12 is arranged above the storage unit 11. The water pipe 12 is branched from a water pipe 13 which is a trunk pipe of a water pipe network, and an outlet of the water pipe 12 is a water supply port 12 </ b> A for the storage unit 11. The water supply port 12A is opened and closed by a water supply valve 12V. The water supply valve 12V includes, for example, a solenoid as a drive source, and is switched between a fully open state and a fully closed state.

  A drain port 11A is provided at a lower portion of the storage section 11, and is opened and closed by a drain valve 11V. The drain valve 11V also includes a solenoid as a drive source, and can be switched between a fully open state and a fully closed state. In addition, the amount of water supplied from the water supply port 12A when the water supply valve 12V is opened is set to be slightly larger than the amount of water discharged from the water discharge port 11A when the drainage valve 11V is opened when the storage unit 11 is full. Has become. One or both of the water supply valve 12V and the drainage valve 11V may be a flow control valve capable of controlling the flow.

  A drain pan 14 is provided below the storage unit 11. Then, the tap water overflowing from the storage unit 11 and the tap water discharged from the drain port 11 </ b> A are received by the drain pan 14. The tap water received by the drain pan 14 is discharged from, for example, an outlet 14A of the drain pan 14 to sewage or the like.

  The storage unit 11 is provided with a stirrer 15. The stirrer 15 includes, for example, a rotating blade 15A that includes a motor as a drive source and is submerged in tap water in the storage unit 11 in a full state. The driving source is arranged above the storage unit 11 by a bracket (not shown). Then, for example, the rotary blade 15A rotates at such a low speed that the tap water is not foamed, and stirs the tap water.

  A pair of electrodes 16 </ b> A and 16 </ b> B are fixed to the storage unit 11, and are immersed in tap water in the storage unit 11. The electrodes 16A and 16B are made of metals having different ionization tendencies from each other. One electrode 16A is made of a metal (for example, platinum, iridium, gold or palladium) which easily reacts with free residual chlorine, while the other is made of the other metal. The electrode 16B is made of a metal that hardly reacts with free residual chlorine (for example, SUS316, SUS316L, SUS430, tungsten, tantalum, titanium, molybdenum, or zirconium).

  The pair of electrodes 16A and 16B are connected to the measuring unit 17, and a voltage generated between the electrodes 16A and 16B is detected by the measuring unit 17.

  The measuring unit 17 includes a resistance element connected between the electrodes 16A and 16B and detects a voltage between both terminals of the resistance element. A switch is provided between the electrodes 16A and 16B so that the contents other than the free residual chlorine in the tap water do not disappear due to the above, so that the connection between the electrodes 16A and 16B is cut off except at the time of detecting the voltage. Is also good.

  The control unit 20 controls the timing of voltage detection by the measuring unit 17 and the operation timing of the agitator 15, the water supply valve 12V, and the drainage valve 11V described above. The control unit 20 has a microcomputer and a storage unit, and the storage unit stores the control program PG1 shown in FIGS. When the residual chlorine detection device 10 is started, the control program PG1 is executed by the microcomputer, and each part is controlled as described below.

  That is, as shown in FIG. 2, the control program PG1 is executed with the activation of the residual chlorine detection device 10, and the storage process (S11) is executed. When the storage process (S11) is executed, the state in which the drain valve 11V is closed and the water supply valve 12V is opened is maintained for a predetermined first water supply time. 12V is closed. Thereby, the storage part 11 is made full.

  In addition, as a configuration other than filling the storage unit 11 with water based on the water supply time as described above, a pair of detection terminals is provided at the upper end of the storage unit 11 and whether the detection terminals are short-circuited by tap water. Whether or not the storage unit 11 is full may be detected depending on whether or not the water supply unit 11 is full, and the water supply valve 12V may be closed.

  Next, time measurement by the main timer is started (S12), and the stirrer 15 is started (S13). Then, the stirrer 15 is continuously operated until the main timer measures a predetermined first check time (for example, 22 hours from the start) (NO loop of S14). This completes the process of removing the free residual chlorine in the tap water stored in the storage unit 11, fills the storage unit 11 with the treated tap water, and immerses the pair of electrodes 16A and 16B in the treated tap water. It will be in the state that was done.

  In addition, although the tap water in the storage part 11 may be left without providing the stirrer 15, the stirring process with the stirrer 15 promotes the process of removing free residual chlorine. The upper surface of the storage unit 11 may be closed, but if the upper surface is open as in the storage unit 11 of the present embodiment, the stored tap water comes into contact with air to remove free residual chlorine. Is promoted. Further, in order to promote the removal treatment of free residual chlorine, a substance which easily binds to free residual chlorine and which hardly binds to other components of tap water may be added to tap water. As such a substance, for example, a metal (iron, iron alloy, or the like) which is easily corroded by binding to free residual chlorine can be used. Further, the rotating blade 15A of the stirrer 15 may be made of such easily corroded metal. Here, since the solubility of metal ions is much smaller than the solubility of ions of non-metallic substances, it is presumed that the influence of oxidation products of metals on the voltage measurement is small. In addition, when it is not necessary to accelerate the process of removing free residual chlorine, the cathode protection may be performed on the rotor 15A, and the cathode protection may be released only when necessary.

  The main timer measures the first check time (YES in S14), and when the stirrer 15 is stopped (S15), the main timer measures a predetermined second check time (for example, 15 minutes from the first check time). (NO loop of S16). Thereby, the treated tap water in the storage unit 11 is hydrostaticized.

  When the main timer measures the second check time (YES in S16), the voltage between the pair of electrodes 16A and 16B immersed in the treated tap water is detected as the first voltage E1 (S17). This voltage detection is performed a plurality of times (for example, 10 times) at predetermined intervals (for example, 1 second), and the average is stored as the first voltage E1.

  After the detection of the first voltage E1, a water replacement process (S18) is performed. In the water replacement process (S18), the state where both the water supply valve 12V and the drainage valve 11V are open is maintained for the second water supply time, and thereafter, both valves 11V and 12V are closed. As a result, the tap water in the storage unit 11 is replaced with untreated tap water that has not been subjected to the treatment for removing free residual chlorine, and the pair of electrodes 16A and 16B is immersed in the untreated tap water. Become.

  Here, the second water supply time is, for example, about 30 minutes, and is obtained experimentally. Specifically, for example, the tap water in the storage unit 11 is colored, and both the water supply valve 12V and the drain valve 11V are opened. It is experimentally determined as 2 water supply times.

  Further, as described above, since the amount of water supplied through the water supply valve 12V is larger than the amount of water discharged through the drainage valve 11V, the tap water is replaced while the tap water overflows from the storage unit 11. Thereby, the storage part 11 is always maintained in a full state, and the immersion state of the electrodes 16A and 16B is maintained constant.

  Next, the process waits until the main timer measures the third check time (for example, 15 minutes after the water replacement process (S18)), and waits for the untreated tap water in the storage unit 11 to be quiescent (NO in S19). ), A voltage between the pair of electrodes 16A and 16B immersed in untreated tap water is detected as the second voltage E2 (S20).

  Next, the absolute value of the value obtained by subtracting the first voltage E1 from the second voltage E2 is calculated as the difference voltage ΔE (S21). Then, depending on whether or not the difference voltage ΔE is equal to or greater than a preset reference difference voltage L1, the free residual chlorine of the tap water is equal to or higher than a reference concentration stipulated by law (for example, 0.1 [ppm] or higher). ) Is determined (S22). If the density is not equal to or higher than the reference density, an abnormality is notified to, for example, a detection main body in a remote place (S23). Then, the main timer is stopped and reset (S24), the process returns to step S12, and the above operation is repeated.

  In the present embodiment, the microcomputer of the control unit 20 executing step S21 corresponds to a “difference calculation unit” described in the claims. Further, in the present embodiment, whether or not the free residual chlorine is equal to or higher than the reference concentration is detected. However, the concentration of the free residual chlorine may be detected from the differential voltage ΔE and a preset data table. Alternatively, the configuration may be such that the value itself of the differential voltage ΔE is output or stored as a detection result which is a substitute value of the concentration of free residual chlorine. Further, the first voltage E1 and the second voltage E2 may be transmitted to the detection main body, and the difference voltage ΔE may be obtained by the detection main body. In this case, the detection main body corresponds to a “difference calculation unit”, The "residual chlorine detector" described in the claims is constituted by the residual chlorine detector 10 and the detection main body.

  The description of the residual chlorine detection device 10 and the residual chlorine detection method of the present embodiment is as above. Next, their effects will be described. As described above, in the residual chlorine detection device 10 and the residual chlorine detection method of the present embodiment, the pair of electrodes 16A and 16B is immersed in the treated tap water that has been subjected to the free residual chlorine removal treatment, and the first voltage E1 is set. To detect. Then, a voltage component due to substances other than free residual chlorine is subtracted from the second voltage E2 detected by immersing the pair of electrodes 16A and 16B in untreated tap water based on the first voltage E1, and a difference voltage ΔE is obtained. Therefore, free residual chlorine can be detected with higher accuracy than before by using the difference voltage ΔE.

  Here, since the pair of electrodes 16A and 16B are fixed to the storage section 11, the detection conditions for the first voltage E1 and the second voltage E2 can be easily made uniform. The surface condition of the pair of electrodes 16A and 16B differs depending on whether they are in contact with air or water, which may be a disturbance factor for voltage detection. Since the storage unit 11 is always kept almost fully filled even when it is replaced with the treated tap water, it is possible to detect the voltage while suppressing disturbance. Further, the flow of tap water can also be a disturbance factor for voltage detection. However, in the present embodiment, the voltage is detected in a state where tap water is hydrostatic, so that voltage detection with reduced disturbance can be performed.

  In the present embodiment, the difference voltage ΔE is obtained from the second voltage E2 and the first voltage E1 detected immediately before the second voltage E2. However, the difference voltage ΔE is obtained from the second voltage E2 and the first voltage E1 detected immediately after the second voltage E2. The difference voltage ΔE may be obtained. In that case, a long processing time for removing free residual chlorine is required between the detection of the first voltage E1 and the second voltage E2. However, as in the present embodiment, the second voltage E2 and its When the difference voltage ΔE is obtained from the first voltage E1 detected immediately before, both the first voltage E1 and the second voltage E2 can be detected in a short time, and the detection conditions can be easily made uniform. Become.

[Second embodiment]
The residual chlorine detection device 10V of the present embodiment is shown in FIG. 4, and mainly differs from the first embodiment in the structure of the storage unit 30. That is, the residual chlorine detector 10V of the present embodiment is provided with the water supply valve 12V and the drainage valve 11V at the upstream and downstream of the branch passage 31 branched from the water supply pipe 13, and stores the portion between them. This is the part 30. The electrodes 16A and 16B are fixed so as to penetrate the storage unit 30. Note that the stirrer 15 and the drain pan 14 are not provided in the residual chlorine detection device 10V of the present embodiment. Other configurations are the same as those of the first embodiment. According to the configuration of the present embodiment, the same operation and effect as those of the first embodiment can be obtained.

[Third embodiment]
The residual chlorine detection device 10W of the present embodiment is shown in FIG. 5 and is a modification of the second embodiment, and separately from the pair of electrodes 16A and 16B penetrating the storage unit 30, a water pipe 13 is provided. Is provided with a pair of electrodes 16C and 16D penetrating through. Then, the first voltage E1 is detected by the electrodes 16A and 16B fixed to the storage unit 30, and the second voltage E2 is detected by the electrodes 16C and 16D fixed to the water pipe 13. Further, based on the difference between when the electrodes 16A and 16B fixed to the reservoir 30 and the electrodes 16C and 16D fixed to the water pipe 13 are immersed in the same tap water and the voltage is detected, the correction coefficient is experimentally determined. In advance, the control unit 20 calculates the difference voltage ΔE by subtracting the value obtained by correcting the first voltage E1 with the correction coefficient from the second voltage E2. Other configurations are the same as those of the second embodiment, and the configuration of the present embodiment also provides the same functions and effects as those of the first and second embodiments.

[Other embodiments]
(1) In the residual chlorine detector 10 of the first embodiment, after detecting the second voltage E2 in step S20, the apparatus is stopped and reset after waiting for the main timer to measure 24 hours (S24). By returning to step S12, the first voltage E1 and the second voltage E2 may be detected at the same time each day. Alternatively, a plurality of storage units 11 and electrodes 16A and 16B may be provided, and the first voltage E1 and the second voltage E2 may be detected a plurality of times every day at predetermined intervals.

(2) In the second and third embodiments, as shown in FIG. 4 and FIG. 5, the cross section of the branch portion 31 that is the storage portion 30 is larger than the cross sections of the other portions. However, the entire storage section 30 may have a pipe structure having a uniform diameter, and the storage section 30 may have the same pipe structure as both end portions of the branch passage 31.

10, 10V, 10W Residual chlorine detector 11, 30 Storage unit 11A Drain port 11V Drain valve 12 Water pipe 12A Water supply port 12V Water supply valve 13 Water pipe 15 Stirrer 16A to 16D Electrode 17 Measurement unit 20 Control unit (Difference calculation Section, valve control section)
E1 first voltage E2 second voltage ΔE differential voltage

Claims (11)

A residual chlorine detector for detecting free residual chlorine in tap water,
A removal treatment unit that removes the free residual chlorine from tap water discharged from a water pipe,
A pair of electrodes having different ionization tendencies,
A first voltage generated between the pair of electrodes in a state where the pair of electrodes is immersed in the treated tap water having been subjected to the removal treatment, and a pair of electrodes disposed in the untreated tap water in which the removal treatment has not been performed. A measuring unit for detecting a second voltage generated between the electrodes in a state in which is immersed,
A difference calculation unit that obtains a difference voltage by subtracting a voltage component due to a substance other than the free residual chlorine from tap water from the second voltage based on the first voltage;
A residual chlorine detection device comprising: The removal processing unit has a storage unit in which tap water discharged from the water pipe is stored for a predetermined reference time or more, and the removal processing is performed by storing the reference time or more,
The residual chlorine detection device according to claim 1, wherein the first voltage and the second voltage are detected in a state where the pair of electrodes are fixed to the storage unit.   3. The residual chlorine detection device according to claim 2, wherein the difference calculation section calculates the difference voltage from the second voltage and a first voltage detected immediately before the detection of the second voltage. 4. A drain port that drains tap water from the reservoir and is opened and closed by a drain valve,
A water supply port that supplies tap water to the storage section and is opened and closed by a water supply valve,
A valve control unit that controls the drain valve and the water supply valve so that the storage unit is always maintained substantially full, including when the treated tap water is replaced with the untreated tap water. The residual chlorine detection device according to claim 2 or 3. The amount of water supplied from the water supply port when the water supply valve is fully open is larger than the amount of water discharged from the water discharge port when the drain valve is fully open,
The residual chlorine detection device according to claim 4, wherein the valve control unit fully opens both the drain valve and the water supply valve when the inside of the storage unit is replaced with the untreated tap water from the treated tap water. .   The residual chlorine detection device according to any one of claims 2 to 5, further comprising a stirrer for stirring tap water in the storage unit.   The residual chlorine detection device according to claim 2, wherein an upper surface of the storage unit is open. A residual chlorine detection method for detecting free residual chlorine in tap water,
While immersing a pair of electrodes having different ionization tendencies in treated tap water that has been subjected to the removal treatment of free residual chlorine from tap water discharged from a water pipe and detecting a first voltage generated between the electrodes, Immersing the pair of electrodes in untreated tap water that has not been subjected to the removal treatment, and detecting a second voltage generated between the electrodes;
From the second voltage, a voltage component due to a substance other than the free residual chlorine in tap water is subtracted based on the first voltage to obtain a differential voltage, and the residual voltage for detecting the free residual chlorine using the differential voltage. Chlorine detection method. The removal treatment is performed by storing tap water discharged from the water pipe in a storage unit for a predetermined reference time or more,
The residual chlorine detection method according to claim 8, wherein the pair of electrodes are fixed to the storage unit to detect the first voltage and the second voltage.   The residual chlorine detection method according to claim 9, wherein the difference voltage is obtained from the second voltage and a first voltage detected immediately before the detection of the second voltage.   The residual chlorine detection method according to claim 9 or 10, wherein the storage section is always kept substantially full, including when the treated tap water is replaced with the untreated tap water.

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