JP2016191605A - Residual chlorine measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a residual chlorine measurement device capable of accurately detecting deterioration of a Zero water purification device.SOLUTION: A residual chlorine measurement device includes; a detection electrode and counter electrode that are immersed in a liquid under measurement; a current measurement unit configured to measure target current that flows between the detection electrode and the counter electrode; path cutoff means capable of temporarily cutting off a current flow path for the target current to flow; and an arithmetic control unit that controls the path cutoff means. Zero calibration is performed based on a value of the current measured when the detection electrode and the counter electrode are immersed in Zero water with chlorine thereof removed by a Zero water purification device. The arithmetic control unit detects deterioration of the Zero water purification device based on a difference between the value of current measured when the detection electrode and the counter electrode are immersed in the zero water and a value of current measured by the current measurement unit while the current flow path is cutoff by the path cutoff means.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a residual chlorine measuring device. More specifically, the present invention relates to a residual chlorine measuring device that can detect deterioration of a zero water purifier that purifies zero water used for zero calibration.

  Conventionally, in order to monitor the residual chlorine concentration of tap water, sewage, pool water, food washing water, industrial water, waste water, etc., a polarographic method or galvanic cell type residual chlorine measuring device capable of continuous operation has been used. Yes.

  For example, in a polarographic residual chlorine measuring device, when a detection electrode (working electrode) made of platinum or gold and a counter electrode made of silver / silver chloride are immersed in sample water, and a predetermined voltage is applied between both electrodes The concentration of residual chlorine in the sample water can be determined by measuring the current (oxidation reduction current) flowing between the two electrodes.

  In the polarographic method and the galvanic cell method, detection sensitivity varies due to temporal and temporary alteration of the electrode, and an error may occur between the measured current value and the residual chlorine concentration. Therefore, in the residual chlorine measuring device, calibration is performed periodically (for example, every few days) (see, for example, Patent Document 1).

  For zero calibration of the residual chlorine measuring device, zero water (dechlorinated water) is used in which chlorine is removed from actual sample water (raw water) such as tap water and the residual chlorine concentration is almost zero. Examples of the zero water purifier include one that removes chlorine by filtering raw water using an activated carbon filter or a filter that combines an activated carbon filter and a hollow fiber filter, and one that irradiates raw water with ultraviolet rays to remove chlorine. Yes (see, for example, Patent Document 2).

  The chlorine removal capacity of such a zero water purifier may be reduced or lost at some point. For example, in the case of a filter type zero water purifier, the chlorine removal capability of the activated carbon filter gradually decreases as it is used, and eventually chlorine remains in the zero water. In addition, in the case of an ultraviolet irradiation type zero water purifier, the chlorine removal capability is reduced due to deterioration of the light source for ultraviolet irradiation and chlorine remains in the zero water, the life of the light source and the zero water purifier Zero water may not be purified due to its own electrical problems. When the zero water purifier is deteriorated as described above, correct zero calibration cannot be performed, and measurement errors and the like are adversely affected. For this reason, maintenance of the zero water purifier is important.

As maintenance of the zero water purifier, for example, in the case of a filter-type zero water purifier, a method of periodically replacing the filter is generally performed. However, in this method, when the frequency of use of the zero water purifier is low, even a sufficiently usable filter is replaced and discarded, resulting in waste. In addition, when the usage frequency is extremely high, or when the chlorine concentration of the sample water is high, the lifetime of the filter becomes shorter than planned, and zero water cannot be maintained in an appropriate state.
As a method for dealing with such a problem, in Patent Document 3, the light transmittance of clean water immediately after the start of use of the filter is used as a reference, and the deterioration of the filter is determined by comparison with the light transmittance of water for each calibration. A method is disclosed.

Japanese Patent Laid-Open No. 5-180799 JP 2005-283287 A JP-A-9-49763

However, although the method disclosed in Patent Document 2 is suitable for an optical measurement device, the residual chlorine measurement of a polarographic method or a galvanic cell method that is affected by the flow rate, electric conductivity, pH, etc. of the liquid to be measured. When trying to apply to the apparatus, there are problems that it becomes complicated and a sufficient effect cannot be obtained.
Polarographic and galvanic cell type residual chlorine measuring devices change their measured values when conditions such as the flow rate of the liquid to be measured, electrical conductivity, and pH are different. Therefore, when applying the method disclosed in Patent Document 2, it is necessary to match the conditions for obtaining the reference and determining the deterioration of the filter. For this reason, for example, if the flow rate of the liquid to be measured is changed after acquiring the reference, it must be temporarily returned to the flow rate at the time of reference acquisition every time it is determined that the filter is deteriorated. Become. Furthermore, when the electric conductivity and pH of raw water are different from those at the time of reference acquisition, the conditions cannot be matched and accurate determination cannot be performed.

  This invention solves the said subject, and the place made into the objective is providing the residual chlorine measuring apparatus which can detect deterioration of a zero water refinement | purification apparatus correctly.

  In order to solve the above problems, a residual chlorine measuring apparatus according to the present invention measures a detection electrode and a counter electrode immersed in a liquid to be measured, and a measurement current that is a current flowing between the detection electrode and the counter electrode. A zero current calibration unit based on a current value when the detection electrode and the counter electrode are immersed in zero water from which chlorine has been removed by a zero water purifier, and the detection electrode and the counter electrode However, in the residual chlorine measuring device for obtaining the residual chlorine concentration in the sample water based on the current value when immersed in the sample water, the path blocking means capable of temporarily blocking the current path through which the current to be measured flows, An arithmetic control unit for controlling the path blocking means, wherein the calculation control section interrupts the current path by the current value when the detection electrode and the counter electrode are immersed in the zero water, and the path blocking means. The Based on a difference between the current value of the current measuring unit is measured in state, and detecting the degradation of the zero water purifier.

  In the above configuration, the arithmetic control unit may output a signal for informing the deterioration of the zero water purifier when the difference exceeds a predetermined threshold.

  According to the configuration of the present invention, it is possible to obtain a current value in an electrically zero (open zero) state in which the current path through which the current to be measured flows is interrupted by the path interrupting unit. And the chlorine concentration of zero water is correctly detectable by taking the difference of the electric current value when measuring zero water, and the electric current value of an electrical zero state. Therefore, it is possible to provide a residual chlorine measuring device that can accurately detect deterioration of the zero water purification device.

It is a schematic diagram of the whole structure of the residual chlorine measuring apparatus which concerns on 1st embodiment of this invention. It is a flowchart of the deterioration detection of the zero water refiner | purifier of the residual chlorine measuring apparatus which concerns on 1st embodiment of this invention. It is a schematic diagram of the whole structure of the residual chlorine measuring apparatus which concerns on 2nd embodiment of this invention.

<First embodiment>
Hereinafter, the residual chlorine measuring apparatus according to the first embodiment of the present invention will be described in detail with reference to FIG.
As shown in FIG. 1, the residual chlorine measuring apparatus 1 according to the present embodiment is a polarographic residual chlorine measuring apparatus that is schematically composed of a detection unit 10 and a main body unit 20.

  The detection unit 10 includes a measurement cell 11 into which the measurement liquid S is introduced, a detection electrode support 12 whose lower part is immersed in the measurement liquid S, and a detection electrode 13 attached to the lower end surface of the detection electrode support 12. In order to vibrate the holder 14, which is formed in a cylindrical shape and whose lower part is immersed in the liquid S to be measured, the counter electrode 15 wound around the outer peripheral surface on the lower end side of the holder 14, and the detection electrode 13 in a circular motion. Motor 16, a flange 17 that supports the detection electrode support 12 inside the holder 14, and a large number of beads 18 for polishing (cleaning) the detection electrode 13.

The detection electrode 13 is made of gold, and the counter electrode 15 is made of silver / silver chloride. The detection electrode 13 and the counter electrode 15 are immersed in the liquid S to be measured in the measurement cell 11. The material of the detection electrode 13 may be a gold alloy or platinum.
The upper end of the detection pole support 12 is attached eccentrically to the rotating shaft 16a of the motor, and the upper end in the length direction is supported on the inner peripheral surface of the holder 14 via the flange 17. The detection pole support 12 precesses around the flange 17 in conjunction with the rotation of the motor 16, and the detection pole 13 vibrates (circulates).

A large number of beads 18 are arranged in a non-fixed state around the detection electrode 13 as a granular abrasive. When the detection electrode 13 vibrates (circulates), the bead 18 comes into contact with the detection electrode 13 to polish (clean) the detection electrode 13. The material of the beads 18 is ceramic or glass. The beads 18 are filled in a mesh cap (not shown) so as not to flow out of the measurement cell 11.
The motor 16 is controlled to rotate at a predetermined rotational speed by an arithmetic control unit 21 described later. The rotational speed of the motor 16 may be arbitrarily changed or may be a fixed value.

  The main body unit 20 includes an arithmetic control unit 21, a current measurement unit 22, a path interruption unit 23, and a display unit 24. A path L1 between the detection electrode 13 and the current measuring unit 22, a line L2 between the counter electrode 15 and the current measuring unit 22, and a line L3 between the motor 16 and the calculation control unit 21. The calculation control unit 21 is connected by a wiring L4, and the current measurement unit 22 and the calculation control unit 21 are connected by a wiring L5.

  The arithmetic control unit 21 controls the entire residual chlorine measuring device 1 and calculates the residual chlorine concentration of the liquid S to be measured from the current value (oxidation reduction current value) or the like input from the current measuring unit 22. Also, storage means (not shown) such as RAM and ROM for storing the input current value, calculation result (residual chlorine concentration, etc.), calibration data (current value at calibration, calibration curve, etc.), various settings, etc. are provided. ing. Furthermore, calculation results, settings, and the like can be displayed on the display unit 24 or output to an external device such as a computer, a data logger, a recorder, or a printer via an output unit (not shown). .

  The current measurement unit 22 has a voltage application mechanism, and applies a predetermined voltage between the detection electrode 13 and the counter electrode 15 via the wirings L1 and L2 based on a signal from the calculation control unit 21. The current measuring unit 22 includes an ammeter, and measures an oxidation-reduction current (current to be measured) flowing between the detection electrode 13 and the counter electrode 15 via the wirings L1 and L2, and the current value (hereinafter referred to as “current measurement value”) “Oxidation-reduction current value”) is output to the arithmetic control unit 21. Residual chlorine measuring apparatus 1 according to the present embodiment is a polarographic method, and the predetermined voltage refers to a voltage in a region (so-called plateau region) in which the current is substantially constant even when the applied voltage changes slightly.

  A normally closed relay 23 is used as the route blocking means 23. In the present embodiment, the relay 23 is disposed in the middle of the wiring L1, which is a current path through which the current to be measured flows. The relay 23 is opened and closed based on a signal from the arithmetic control unit 21. Therefore, the residual chlorine measuring apparatus 1 according to the present embodiment has a configuration in which the current path through which the current to be measured flows can be temporarily interrupted in the wiring L1. The relay 23 only needs to be in the current path through which the current to be measured flows, and may be disposed in the middle of the wiring L2, or may be disposed on the substrate to which the wiring L1 or the wiring L2 is connected. .

  The residual chlorine measuring apparatus 1 according to the present embodiment configured as described above performs various operations such as calibration, measurement of sample water, and detection of deterioration of the zero water purifier.

[Proofreading]
The residual chlorine measuring device 1 performs zero calibration and span calibration. Note that the calibration may be a mode in which the zero calibration is simply performed in a normal state and the zero calibration and the span calibration are continuously performed as necessary.
In the zero calibration, zero water having a residual chlorine concentration of substantially zero is used as the measured solution S, and the detection electrode 13 and the counter electrode 15 are immersed in the measured solution S (zero water). The current measuring unit 22 applies a predetermined voltage, measures the oxidation-reduction current value Iz, and outputs it to the calculation control unit 21. In span calibration, a span calibration solution selected in consideration of the measurement range is used as the measured solution S, and the detection electrode 13 and the counter electrode 15 are immersed in the measured solution S (span calibration solution). The current measuring unit 22 applies a predetermined voltage, measures the oxidation-reduction current value Is, and outputs the measured value to the calculation control unit 21.

Zero water is purified by a zero water purifier (not shown). Zero water purification equipment, for example, removes residual chlorine by filtering sample water or tap water (raw water) with an activated carbon filter or a filter that combines an activated carbon filter and a hollow fiber filter, or irradiates raw water with ultraviolet rays. However, the present invention is not limited to these, and it may be a pure water production apparatus that produces pure water by filtering tap water or the like.
As the span calibration solution, for example, an aqueous solution obtained by diluting a sodium hypochlorite solution with zero water to a predetermined concentration is used. Sample water or tap water may be used as the span calibration solution.

  The residual chlorine concentration Cz of zero water and the residual chlorine concentration Cs of the span calibration solution can be confirmed using, for example, the DPD method (diethyl-p-phenylenediamine colorimetric method). This confirmation is performed manually. Note that the residual chlorine concentration Cz of zero water may be regarded as zero, and in this case, confirmation of the residual chlorine concentration Cz by manual operation can be omitted.

  The arithmetic control unit 21 creates a calibration curve from the oxidation / reduction current value Iz and residual chlorine concentration Cz of zero water and the oxidation / reduction current value Is and residual chlorine concentration Cs of the span calibration solution. The calibration curve, measured values of zero water and span calibration solution (oxidation reduction current value Iz, residual chlorine concentration Cz, oxidation reduction current value Is, residual chlorine concentration Cs) are stored in the calculation control unit 21.

[Measurement of sample water]
The residual chlorine measuring device 1 measures the residual chlorine concentration Cx using sample water such as clean water to be measured as the liquid S to be measured.
In the measurement of the sample water, the detection electrode 13 and the counter electrode 15 are immersed in the measured solution S (sample water) introduced into the measurement cell 11. The current measuring unit 22 applies a predetermined voltage, measures the oxidation-reduction current value Ix, and outputs it to the calculation control unit 21. The arithmetic control unit 21 obtains the residual chlorine concentration Cx corresponding to the input oxidation-reduction current value Ix based on the calibration curve stored at the time of calibration.
The obtained residual chlorine concentration Cx is output to the display unit 24, and the residual chlorine concentration Cx is displayed on the display unit 24. The residual chlorine concentration Cx may be output to an external device (not shown) such as a computer.

[Detection of deterioration of zero water purification equipment]
The residual chlorine measuring device 1 detects the deterioration of the zero water purification device using the zero water oxidation-reduction current value Iz (hereinafter referred to as “zero water current value Iz”). Degradation detection of the zero water purifier is performed by executing the following steps.
Step A1) The relay 23 is opened (opened) to cut off a current path (hereinafter simply referred to as “current path”) through which the current to be measured flows.
Step A2) A current value Iez in a state where the current path is interrupted (hereinafter referred to as “electrical zero current value Iez”) is measured.
Step A3) The relay 23 is closed (closed) to release the interruption of the current path.
Step A4) A difference ΔI between the zero water current value Iz stored at the time of zero calibration and the electrical zero current value Iez obtained in step A2 is calculated.
Step A5) It is determined whether or not the difference ΔI exceeds a preset threshold value It. If the difference ΔI is exceeded, the process proceeds to Step A6. If not, the deterioration detection of the zero water purifier is terminated.
Step A6) A signal (deterioration notification signal) for notifying deterioration of the zero water purifier is generated and output, and the detection of deterioration of the zero water purifier is terminated.

The detection of deterioration of the zero water purifier is started by a predetermined sequence or manual operation. Usually this is done following calibration.
Hereinafter, each step will be further described with reference to FIGS. 1 and 2.

  In step A1, the arithmetic control unit 21 outputs a signal for opening the relay 23. When the relay 23 is opened, the current path is temporarily interrupted.

  In step A2, the calculation control unit 21 captures and stores the current value Iez measured by the current measurement unit 22 in a state where the current path is interrupted.

  In step A3, the arithmetic control unit 21 outputs a signal for closing the relay 23. When the relay 23 is closed, the interruption of the current path is released.

In step A4, the arithmetic control unit 21 reads the latest zero water current value Iz stored at the time of zero calibration and the electrical zero current value Iez stored in step A2. And the calculation control part 21 calculates difference (DELTA) I of the zero water current value Iz and the electrical zero current value Iez using following Formula, and memorize | stores difference (DELTA) I.
ΔI = Iz−Iez
That is, the difference ΔI is obtained by subtracting the base electrical zero current value Iez from the zero water current value Iz, which is the redox current value of zero water purified by the zero water purifier, It is a value according to the concentration.

In step A5, the calculation control unit 21 compares the preset threshold value It stored in the calculation control unit 21 with the difference ΔI calculated in step A4. As a result, when the difference ΔI exceeds the threshold It, it is determined that the zero water purifier is deteriorated, and the process proceeds to Step A6. On the other hand, when the difference ΔI does not exceed the threshold value It, the detection of deterioration of the zero water purifier is terminated.
The threshold value It is a value that is set as appropriate depending on the environment in which the residual chlorine measuring device 1 is used.

In step A6, the arithmetic control unit 21 generates and outputs a deterioration notification signal. The output deterioration notification signal is sent to the display unit 24, and the display unit 24 displays that the zero water purifier is deteriorated. In addition, the deterioration notification signal is sent to an external device such as a computer, data logger, recorder, printer, etc. via an output unit (not shown), and it is notified that the zero water purifier is deteriorated by display or voice. Is done. Note that the display unit 24 and the external device may display that the zero water purifier is deteriorated and may indicate that the maintenance of the zero water purifier is necessary.
After step A6, the detection of deterioration of the zero water purifier is terminated.

Since the sample water cannot be measured while the relay 23 is in the open state, the arithmetic control unit 21 outputs a signal indicating that the deterioration of the zero water purifier is being detected (detecting signal). Also good.
For example, in step A5, the arithmetic control unit 21 further compares the difference ΔI with a determination reference value Ij smaller than the threshold It, and generates a warning signal if threshold It> difference ΔI> determination reference value Ij. May be output. Further, for example, in step 6, a zero calibration error signal may be output instead of the deterioration notification signal.
Note that the arithmetic control unit 21 may send the deterioration notification signal or the like only to the external device without sending it to the display unit 24. The arithmetic control unit 21 may not generate or output a deterioration notification signal or the like immediately, but may generate or output a deterioration notification signal or the like in response to an external request. Only the difference ΔI may be output without generating a signal or the like.
Step A3 may be performed in parallel with any of steps A4 to A6, or may be performed after any of them.

In the detection of the deterioration of the zero water purification device, the zero water current value Iz stored at the time of zero calibration is used, and therefore, the detection of the deterioration of the zero water purification device is preferably started without leaving a time interval with the calibration. It is preferable to start in synchronization with the end of calibration.
Moreover, the aspect by which the deterioration detection of a zero water refiner | purifier is performed between zero calibration and span calibration may be sufficient.

[Function and effect]
In the present embodiment, by providing the relay 23, the current path through which the current to be measured flows is temporarily interrupted, and the current value (zero) as a base value for obtaining the difference ΔI ( An electrical zero current value Iez) can be obtained. Since the electrical zero current value Iez is a value that is not related to the flow rate, temperature, pH, or the like of the liquid S to be measured, a stable base value can always be obtained.

  The difference ΔI between the zero water current value Iz and the electrical zero current value Iez is a value corresponding to the chlorine concentration of zero water, and depends on the chlorine removal capability of the zero water purifier. Therefore, by monitoring this difference ΔI, it is possible to accurately detect the state of reduced residual chlorine removal capability of the zero water purifier.

  Thus, according to the residual chlorine measuring apparatus 1 which concerns on this Embodiment, by calculating | requiring difference (DELTA) I, the chlorine concentration of zero water can be detected correctly and deterioration of a zero water refinement | purification apparatus can be detected correctly. . Therefore, the user accurately grasps the maintenance timing of the zero water purifier that varies depending on the state of the liquid S to be measured and the usage status of the residual chlorine measuring device 1, and maintains the zero water purifier at an appropriate timing. can do. Therefore, the residual water measuring device 1 can be used in a state in which the zero water used for zero calibration is kept in an appropriate state and accurate zero calibration is performed. For example, the waste of the filter which comprises a zero water refiner | purifier can be eliminated.

<Second Embodiment>
Next, a residual chlorine measuring apparatus according to the second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The residual chlorine measuring device 2 according to the present embodiment includes a detection unit 10, a main body unit 20, and a supply unit 30 that supplies the liquid S to be measured to the measurement cell 11.

  As shown in FIG. 3, the supply unit 30 includes a sample water supply channel 31 that supplies the sample water S1 to the measurement cell 11, a zero water purification device 32 that purifies the zero water S2, and a zero water purification device 32. A zero water supply channel 33 that is connected and supplies zero water S2 to the measurement cell 11, and a solenoid valve 34 that is provided in the sample water supply channel 31 and the zero water supply channel 33 and opens and closes the channels 31, 33. It is equipped with.

The zero water purifier 32 is a filter capable of removing chlorine, and includes, for example, a filter filled with activated carbon. The zero water S2 is obtained by using the sample water S1 or tap water as raw water and filtering it through the zero water purifier 32. The zero water purifier 32 may include a filter such as a hollow fiber that removes turbidity and the like. The zero water purification device 32 may be an ultraviolet irradiation type device, a pure water production device, or the like.
The zero water S2 preferably has the same conditions such as electrical conductivity and pH that affect the measurement of residual chlorine as the sample water S1, so that the sample water S1 can be activated carbon filter or activated carbon filter and hollow fiber filter. It is preferable that it is what filtered with the filter which combined.

The electromagnetic valve 34 has an electromagnetic valve 34 a provided in the sample water supply flow path 31 and an electromagnetic valve 34 b provided in the zero water supply flow path 33. The electromagnetic valve 34 may be constituted by a single three-way electromagnetic valve connected to both flow paths 31 and 33.
The electromagnetic valve 34 (electromagnetic valve 34a, electromagnetic valve 34b) and the arithmetic control unit 21 are connected by a wiring L6. The electromagnetic valve 34 is opened and closed based on a signal from the arithmetic control unit 21. Thereby, the measured liquid S introduced into the measurement cell 11 can be switched to either the sample water S1 or the zero water S2.

The residual chlorine measuring apparatus 2 according to the present embodiment performs operations of calibration, measurement of sample water, and detection of deterioration of the zero water purifier. In any operation, the open / close state of the electromagnetic valve 34 is switched by a signal from the arithmetic control unit 21, and the measured liquid S to be introduced into the measurement cell 11 is automatically switched to either the sample water S1 or the zero water S2. Except for this, it is performed in the same manner as in the first embodiment.
Moreover, the residual chlorine measuring device 2 can automatically perform zero calibration without any manual intervention.

[Automatic zero calibration]
The residual chlorine measuring apparatus 2 according to the present embodiment omits span calibration at normal times and automatically performs only zero calibration simply. The automatic zero calibration is started by interrupting the measurement of the sample water at predetermined time intervals by a timer or the like built in the calculation control unit 21. Hereinafter, automatic zero calibration will be described.

  The arithmetic control unit 21 closes the electromagnetic valve 34a and outputs a signal for opening the electromagnetic valve 34b. Thereby, the introduction of the sample water S1 into the measurement cell 11 is stopped, and the introduction of the zero water S2 is started. Then, it waits for a predetermined time until the inside of the measurement cell 11 is completely replaced with zero water S2 (step B1).

  Next, the arithmetic control unit 21 takes in and stores the redox current value (zero water current value) Iz of the zero water S2 measured by the current measuring unit 22 (step B2).

  Next, the arithmetic control unit 21 compares the zero water current value Iz stored in step B2 with the zero water current value Iz at the previous calibration, and corrects the zero point when there is a deviation (shifts the calibration curve). Stored) (step B3).

Next, the arithmetic control unit 21 outputs a signal for closing the electromagnetic valve 34b and opening the electromagnetic valve 34a. Thereby, the introduction of the zero water S2 into the measurement cell 11 is stopped, and the introduction of the sample water S1 is started. Then, it waits for a predetermined time until the inside of the measurement cell 11 is completely replaced with the sample water S1 (step B4).
After step B4, the automatic zero calibration operation is terminated.
Note that step B3 may be performed in parallel with step B4, or may be performed after step B4.

  In the present embodiment, detection of deterioration of the zero water purifier is performed following the automatic zero calibration. At this time, the zero water current value Iz stored by the automatic zero calibration is read, and a difference ΔI from the electrical zero current value Iez is calculated.

Note that the automatic zero calibration and the detection of deterioration of the zero water purifier need not be independent operations, and both steps may be combined. Moreover, both may be performed in parallel. For example, it can be executed in the following manner.
(1) First, Steps A1 to A3 for detecting deterioration of the zero water purifier are performed.
(2) Next, Steps B1 to B2 of automatic zero calibration are performed.
(3) Next, steps A4 to A6 for detecting the deterioration of the zero water purifier are performed.
(4) Next, Steps B3 to B4 of automatic zero calibration are performed.
For example, the following aspects may be sufficient.
(1) First, the automatic zero calibration step B1 and the zero water purification device deterioration detection step A1 to step A3 are performed in parallel.
(2) Next, steps B2 to B3 of automatic zero calibration are performed.
(3) Next, steps A4 to A6 for detecting the deterioration of the zero water purifier and step B4 for automatic zero calibration are performed in parallel.

<Other embodiments>
The residual chlorine measuring devices 1 and 2 according to the respective embodiments are of a polarographic type, and the detection electrode support 12 precesses and the detection electrode 13 vibrates in a circular motion. The pole support 12 may be of a type that rotates about its axis or a type that vibrates.
Moreover, the residual chlorine measuring devices 1 and 2 may be a galvanic cell system that performs measurement of the oxidation-reduction current without applying an applied voltage, instead of the polarographic system.

  In the second embodiment, the residual chlorine measuring device 2 includes the zero water purification device 32 in the supply unit 30, but the zero water purification device 32 is connected to the sample water supply channel 31 (supply unit 30). It may be provided separately outside the upstream side).

  As mentioned above, although embodiment of this invention was described with reference to drawings, each embodiment is not restricted to the said description, It can change in the range which does not deviate from the meaning of this invention.

DESCRIPTION OF SYMBOLS 1, 2 ... Residual chlorine measuring device, 13 ... Detection electrode, 15 ... Counter electrode, 21 ... Calculation control part, 22 ... Current measurement part, 23 ... Relay (path | route interruption | blocking means), 32 ... Zero water purification apparatus,
S: Liquid to be measured, S1: Sample water, S2: Zero water.

Claims (2)

A detection electrode and a counter electrode immersed in the liquid to be measured, and a current measurement unit that measures a measurement current that is a current flowing between the detection electrode and the counter electrode,
Zero calibration was performed based on the current value when the detection electrode and the counter electrode were immersed in zero water from which chlorine was removed by a zero water purifier, and the detection electrode and the counter electrode were immersed in sample water. In the residual chlorine measuring device for determining the residual chlorine concentration in the sample water based on the current value at the time,
A path blocking means capable of temporarily blocking a current path through which the current to be measured flows;
An arithmetic control unit for controlling the route blocking means,
The calculation control unit includes a current value when the detection electrode and the counter electrode are immersed in the zero water, and a current value measured by the current measurement unit in a state where the current path is blocked by the path blocking unit. The residual chlorine measuring device which detects deterioration of the zero water refining device based on the difference of these.   The residual chlorine measuring device according to claim 1, wherein the arithmetic control unit outputs a signal notifying deterioration of the zero water purifier when the difference exceeds a predetermined threshold.

Images