JP2001141692A - Residual chlorine concentration measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a residual chlorine concentration measuring device capable of constantly and continuously measuring without electrode contamination, and constantly and stably and accurately measuring an electrolytic current at a detection electrode and improving detection accuracy. It is in. SOLUTION: A pair of electrodes provided in a cell through which a liquid to be measured flows, a reference electrode, and the electrode pair are connected to each other,
A pair of switch units for selecting an electrode for detecting residual chlorine, a voltmeter capable of detecting the potential of any one of the selected electrodes with respect to the reference electrode, and controlling the voltmeter to a specific voltage. A variable power supply unit provided between the electrode pairs, a control unit that can alternately select an electrode for inverting and detecting an applied voltage between the electrode pairs through the connection of the switch unit, A residual chlorine concentration measuring device, comprising: an ammeter for detecting an incoming / outgoing current of the device; and a computing unit for computing a residual chlorine concentration from a current value of the ammeter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a residual chlorine concentration apparatus for determining the concentration of residual chlorine contained in a liquid to be measured by a reduction reaction at a detection electrode. High residual chlorine concentration measurement apparatus.

[0002]

2. Description of the Related Art In recent years, components to be measured contained in a liquid to be measured are electrolytically oxidized or reduced using a detection electrode provided in a flow path, and the concentration is measured by utilizing the concentration dependence of a current value flowing at that time. Various concentration measuring devices for continuous measurement have been developed.

[0003] One of the conventional concentration measuring devices is a residual chlorine concentration measuring device. In order to detect the concentration of residual chlorine contained in the liquid to be measured, the concentration of the residual chlorine contained in the liquid to be measured is extremely high. The reduction is to detect the electrolytic current flowing through the detection electrode to calculate the residual chlorine concentration in the liquid to be measured. However, in the conventional residual chlorine measuring apparatus, a deposit is easily attached to the detection electrode at which the residual chlorine is reduced, and contamination is likely to occur. This often deteriorates the electrode and deteriorates the detection accuracy of the electrolytic current.

The following method has conventionally been adopted as a method for recovering performance by regenerating an electrode deteriorated due to adhesion or the like in response to such deterioration of the detection electrode. (1) A method of electrolytic cleaning by applying a potential so that a reverse current flows to the detection electrode. (2) A method of cleaning and regenerating using an abrasive or the like to remove contaminants attached to the detection electrode ( 3) The detection electrode surface is brought into contact with a flowable-filled solid abrasive or the like, as typified by a rotating electrode method in which the detection electrode is rotated by an external drive source, and foreign substances adhere to the detection electrode surface. (4) A detection electrode is disposed on the inner wall of the cell, and a liquid to be measured including ceramic balls having abrasiveness is passed through the cell.
A method has been proposed in which a ceramic ball or the like is turned by using this flow rate to make direct contact with the detection electrode to polish the surface.

[0005]

However, the following problems exist in the conventional measures for deterioration of the concentration measuring apparatus. That is, in the method (1) of regenerating the detection electrode by electrolytic cleaning, it is necessary to apply a potential so that a current flows in the opposite direction to the detection electrode, and it is detected whether the detection electrode has deteriorated during the measurement. This is a point that requires a separate method. further,
When performing the washing, it is necessary to temporarily stop the concentration measuring device, so that continuous and stable measurement cannot be performed. Similarly, in the method (2) of cleaning using an abrasive, it was necessary to temporarily stop the concentration measuring device. In addition, the operation of polishing the detection electrode is complicated, and the method (2) has a problem that continuous and stable measurement cannot be performed.

Further, the method (3) of polishing the surface of the detection electrode with an abrasive or the like using a rotating electrode or the like can reduce the amount of deposits on the surface of the detection electrode, but on the other hand, the flowing abrasive is always uniform. It is difficult to keep the electrode in a stable state because it is difficult to make contact with the electrode surface, and the surface of the detection electrode changes due to the roughening and deformation of the electrode surface due to the abrasive polishing the electrode. The characteristics are easy to change, and the electrode life is shortened and frequent electrode replacement is required.
The measurement cannot be performed stably and accurately over a long period of time. In the method of (4) for polishing the surface by using the flow rate of the liquid to be measured containing an abrasive such as a ceramic ball, it is difficult to keep the electrode state constantly stable, as in (3). Since the abrasive sharpens the electrode, the area of the detection electrode changes to change the characteristics, the life of the electrode is short, and continuous stable and accurate measurement cannot be performed.

Accordingly, the present invention is to solve such a conventional problem, and provides a residual chlorine concentration measuring device which is less likely to cause electrode contamination, can perform continuous measurement, and can always measure accurately and stably. It is in.

[0008]

In order to achieve this object, a residual chlorine concentration measuring apparatus according to the present invention comprises a cell into which a liquid to be measured is introduced, a pair of electrodes and a reference electrode provided in the cell. A switch unit that can select one of the pair of electrodes as a detection electrode for detecting residual chlorine in the liquid to be measured, and the other as a counter electrode, and a voltmeter that detects the potential of the detection electrode with respect to the reference electrode. A variable power supply unit that adjusts the voltage between the pair of electrodes to control the voltmeter to a predetermined voltage, and a polarity of a voltage applied between the pair of electrodes is inverted by the switch unit to set a detection pole. It is characterized by comprising a control unit for alternately selecting, a current meter for detecting a current value flowing through the detection electrode, and a calculation unit for calculating a residual chlorine concentration from the current value.

According to this configuration, contamination of the electrode hardly occurs, continuous measurement is possible, and stable measurement can be always performed with high accuracy.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The invention according to claim 1 is a method for measuring a cell into which a liquid to be measured is introduced, a pair of electrodes and a reference electrode provided in the cell, and one of the pair of electrodes to be measured. A switch that can be used as a detection electrode for detecting residual chlorine in the liquid, and the other as a counter electrode, a voltmeter that detects the potential of the detection electrode with respect to the reference electrode, and controls the voltmeter to a predetermined voltage. A variable power supply unit for adjusting the voltage between the pair of electrodes, a control unit for inverting the polarity of the voltage applied between the pair of electrodes by the switch unit and alternately selecting a detection electrode, and the detection electrode. Since the residual chlorine concentration measurement device is provided with an ammeter for detecting a current value flowing through the device and a calculation unit for calculating the residual chlorine concentration from the current value, the control unit switches the switch unit. One of the pair of electrodes It is possible to select the output electrode and the other as the counter electrode, invert the polarity of the applied voltage and alternately select the detection electrode, wash the electrode while continuing measurement, improve accuracy, and enable continuous measurement .

The invention according to claim 2 of the present invention is characterized in that the pair of electrodes are made of an electrode material forming the same current density, and are arranged at the same distance from the reference electrode. Since the residual chlorine concentration measuring apparatus according to claim 1, the pair of electrodes are electrically equivalent to each other, and can measure accurately even if the polarity of the electrode applied to the electrode is reversed.

According to a third aspect of the present invention, when power is supplied for a predetermined continuous power supply time by the variable power supply unit, the control unit switches the switch unit to invert the detection pole. Since the residual chlorine concentration measuring device according to item 1, the detection electrode is automatically inverted after a predetermined continuous energizing time has elapsed, so that the two electrodes are deteriorated to the same extent and the electrodes are washed by the inversion. Accuracy is improved and continuous measurement is possible.

The invention according to claim 4 of the present invention is characterized in that when the timer means measures a predetermined time, the control unit switches the switch unit to invert the control unit.
Since the detection electrode is automatically inverted after a certain period of time, the degree of contamination of the two electrodes can be made the same with a simple device. Washing improves measurement accuracy and enables continuous measurement.

According to a fifth aspect of the present invention, there is provided a cell into which a liquid to be measured is introduced, a pair of electrodes and a reference electrode provided in the cell, and one of the pair of electrodes being connected to the liquid to be measured. A contact reversing unit that can be used as a detection electrode for detecting residual chlorine therein, and the other can be selected as a counter electrode, a voltmeter that detects the potential of the detection electrode with respect to the reference electrode, and controls the voltmeter to a predetermined voltage. A variable power supply unit for adjusting the voltage between the pair of electrodes, a control unit for inverting the polarity of the voltage applied between the pair of electrodes by the contact inversion unit and alternately selecting a detection pole, and Since the residual chlorine concentration measuring device is provided with an ammeter for detecting a current value flowing through the pole and a calculating unit for calculating the residual chlorine concentration from the current value, the control unit drives the contact reversing unit. To detect one of the pair of electrodes. Electrode, and selects the other a counter electrode, reversing the polarity of the applied voltage can be selected alternately possible detection electrode, the electrode is cleaned while continuing the measurement, improved accuracy, allowing continuous measurement.

The invention according to claim 6 of the present invention is characterized in that, when the variable power supply unit supplies electricity for a predetermined continuous conduction time, the control unit switches the contact inversion unit to invert the detection pole. Since the residual chlorine concentration measuring apparatus according to claim 5, the detection electrode is automatically inverted after a predetermined continuous energizing time has elapsed, the two electrodes are substantially degraded to the same degree, and the life is extended. As a result, the electrode is washed, the accuracy is improved, and continuous measurement is possible.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

(Embodiment 1) FIG. 1 is a configuration diagram showing a residual chlorine concentration measuring apparatus according to Embodiment 1 of the present invention.

In FIG. 1, reference numeral 1 denotes a cell in which an electrode is provided for measuring the residual chlorine concentration in the liquid to be measured while passing the liquid to be measured, and 2a denotes a cell to be measured containing residual chlorine in the cell 1. An introduction pipe for introducing the liquid, a discharge pipe 2b for discharging the liquid to be measured containing residual chlorine in the cell 1, and 3, 4 provided in the cell 1 and connected to each other via a variable power supply unit 7 described later. One is a detection electrode, the other is a counter electrode, and a pair of electrodes, which can detect a residual chlorine concentration by measuring an oxidation-reduction current generated by an oxidation-reduction reaction on the surface, and 5 is a pair of electrodes 3 and 4. The reference electrode 6 is a reference electrode for providing a reference potential for measuring the potential of the electrode serving as the detection electrode. The reference electrode 6 is the electrode 3 serving as the detection electrode among the electrodes 3 and 4 with respect to the reference electrode 5.
A voltmeter indicating the potential difference between the voltmeter 4 and 7; a variable power supply unit provided between the electrodes 3 and 4 for controlling the voltmeter 6 to a predetermined voltage; and 8 a redox generated by an electrode reaction between the electrodes 3 and 4. A current detection unit 9 for measuring the current, a calculation unit 9 for calculating the residual chlorine concentration based on the oxidation-reduction current measured by the current detection unit 8, and a reference numeral 10 connected to the electrodes 3 and 4 provided in the cell 1 A switch unit that can select one of the electrodes 3 and 4 as a detection electrode and the other as a counter electrode, and reverse the selection to invert the polarity of the applied voltage;
Reference numeral 1 denotes a control unit that controls the switch unit 10 and the variable power supply unit 7, and controls the potential of the electrode serving as the detection electrode among the selected electrodes 3 and 4 to a predetermined potential.

The operation and details of the constituent elements of the thus configured residual chlorine concentration measuring apparatus will be described.

As shown in FIG. 1, the liquid to be measured containing residual chlorine is introduced into the cell 1 through the introduction pipe 2a. After the concentration measurement, the liquid to be measured is discharged from the discharge pipe 2b. In the cell 1, a pair of electrodes 3 and 4 for detecting the concentration of residual chlorine by causing the liquid to be measured to undergo an electrode reaction, and the potential of the electrode serving as a detection electrode among the electrodes 3 and 4 is set to a predetermined potential. The reference electrode 5 for giving a potential to be a reference for the adjustment is provided so as to protrude. Each of them is immersed in the liquid to be measured in flowing water. Electrodes 3 and 4 are switch unit 1
0, and the switch unit 10 is further connected to the variable power supply unit 7 and the current detection unit 8. The switch unit 10 inverts the polarity of the output of the variable power supply unit 7 and
Are provided with two contacts for the electrodes 3 and 4, respectively. By switching the switch unit 10, the electrode 4 becomes a counter electrode when the electrode 3 is a detection electrode, and the electrode 3 becomes a counter electrode when the electrode 4 is a detection electrode.

As described above, since the electrode 3 and the electrode 4 are connected to the variable power supply unit 7, the liquid to be measured is introduced into the cell 1 and the potential for reducing the residual chlorine in the liquid to be measured is variable. When the voltage is applied by the power supply unit 7, an oxidation-reduction reaction occurs on the surfaces of the electrodes 3 and 4 according to the concentration of the liquid to be measured, and the electrodes 3 and 4
During this time, an oxidation-reduction current flows, which can be measured by the current detection unit 8. In the first embodiment, the potential at which the reduction reaction of Cl2 + 2e- → 2Cl- occurs in the residual chlorine is applied, and the residual residual chlorine ion, hypochlorous acid, etc. Although the chlorine concentration is determined by conversion, the overall residual chlorine concentration may be determined by conversion from the oxidation-reduction reaction of hypochlorite ion or hypochlorous acid by changing the applied potential. This is because the proportion of these residual chlorine components is determined if the pH is constant, so that if one component is measured, the concentration of the other component and the whole can be estimated. In the case of the above potential for reducing chlorine, an electrolytic reduction reaction occurs on the detection electrode surface, and an electrolytic oxidation reaction occurs on the counter electrode surface.

Since the oxidation-reduction current flowing between the detection electrode and the counter electrode has a concentration dependency with respect to the residual chlorine concentration as described above, by utilizing this relationship, the residual chlorine of the first embodiment is utilized. The concentration measuring device calculates the concentration of residual chlorine contained in the liquid to be measured.

Meanwhile, in the detection electrode, a reduction reaction must be caused on the electrode surface. In the present invention, a reference electrode 5 for generating a reference potential is used in order to accurately apply a potential for causing this reaction to a target substance. First, after detecting the potential of the detection electrode with the voltmeter 6, the control unit 11 adjusts the potential of the detection electrode to a predetermined potential at which the residual chlorine is reduced when viewed from the reference electrode 5. In addition,
The control unit 11 controls the variable power supply unit 7 and also controls the switch unit 10 for selecting a detection electrode and a counter electrode.

The electrode 3 and the electrode 4 are connected to one of the electrodes 3 and 4
It is desirable that both the electrodes 3 and 4 are arranged at the same distance from the reference electrode 5 so that the potentials from the reference electrode 5 are equal and a detection current is obtained when is selected as the detection electrode. The electrode materials used for the electrodes 3 and 4 are as follows:
All of them are electrically equivalent, and it is sufficient that an electrode material that forms the same current density when the same potential is applied to the reference electrode 5 is used and is disposed in the cell 1. There is no particular limitation.

If only one of the electrodes is continuously used as a detection electrode, scale, slime, or other ionic components adhere to the electrode surface, and the electrodes 3 and 4 are contaminated and deteriorated, and a predetermined current value is reduced. This makes it difficult to obtain accurate measurements. Therefore, in such a case, the connection of the switch unit 10 provided on the electrodes 3 and 4 is switched so that the electrode used as the counter electrode is reversed so as to be used as the detection electrode, and the other electrode is used as the counter electrode. At this time, the voltage applied between the electrodes 3 and 4 is inverted. In other words, since the electrode switched from the counter electrode to the detection electrode is a clean electrode in which deposits such as salts are eluted because an oxidation reaction has occurred on the surface as a counter electrode, this is selected as the detection electrode. Accurate and accurate detection current can be obtained. In addition, the electrode that has been used as a detection electrode until now can be used as a counter electrode,
A reverse current can be passed, and the surface of the electrode deteriorated by contamination can be oxidized and cleaned.

By thus switching the switch section 10 provided to be connected to the pair of electrodes 3 and 4 alternately,
Since the electrodes 4 and 4 can be used alternately as the detection electrode and the counter electrode, the electrodes 3 and 4 are alternately regenerated while the measurement is continued, so that a stable detection current can always be detected, and the accuracy in the measurement can be increased.

By the way, the switching of the switch unit 10 is as follows.
The detection may be performed when the magnitude of the detection current when the detection electrode is selected drops. Since the detection current drops because the adhesion of the scale or the like proceeds in proportion to the continuous energizing time, by detecting the continuous energizing time of the variable power supply unit 7 provided between the pair of electrodes 3 and 4, the application time is determined. The control unit 11 may switch the switch unit 10 when a predetermined time has passed.

In addition, in order to control the potential orientation of the pair of electrodes 3 and 4, a timer may be provided in the control unit 11 and the switch unit 10 may be automatically switched by the control unit 11 at predetermined time intervals. Switching can be performed by simpler means than detecting the continuous energizing time, and contamination of the electrodes 3 and 4 can be prevented.

As described above, the polarity of the electrodes 3 and 4 is alternately inverted by switching the switch section 10 alternately.
The electrode selected as the detection electrode can always detect the detection current stably in a clean and stable manner, and the counter electrode can wash and regenerate the electrode, enabling continuous detection and accurate detection of residual chlorine concentration. .

As described above, according to the first embodiment of the present invention, the pair of electrodes 3 and 4 are provided at positions symmetrical with respect to the reference electrode 5, and the switch unit connected to the pair of electrodes 3 and 4 is provided. Since the electrodes are alternately switched, deterioration of the electrodes 3 and 4 can be prevented, the redox current can be detected easily and stably continuously, and a residual chlorine concentration measuring device with high detection accuracy can be obtained.

(Embodiment 2) FIG. 2 is a block diagram showing a residual chlorine concentration measuring apparatus according to Embodiment 2 of the present invention.

In FIG. 2, a cell 1, an inlet tube 2a, an outlet tube 2b, a pair of electrodes 3, 4, a reference electrode 5, a voltmeter 6, a variable power supply unit 7, a current detection unit 8, a calculation unit 9, and a control unit 11 Are the same as those in FIG. Reference numeral 12 denotes a contact reversing unit such as a motor for rotating the electrodes 3 and 4 for alternately reversing the arrangement positions of the electrodes 3 and 4 provided in the cell 1. Reference numeral 13 denotes an integrated contact reversing unit 12 and the electrodes 3 and 4. The supporting members 14a and 14b are electrode contacts with the electrodes 3 and 4.

The arrangement and operation of the constituent elements of the residual chlorine concentration measuring apparatus according to the second embodiment will be described.

As shown in FIG. 2, in the cell 1 through which the liquid to be measured flows, the inner ends of the electrodes 3 and 4 for detecting the residual chlorine due to the electrode reaction of the liquid to be measured are connected to the liquid to be measured. It is immersed inside and protrudes inward. This electrode 3,
Numeral 4 is integrally formed with supporting members 13 having insulating properties. The support member 13 is rotationally driven together with the electrodes 3 and 4 by the contact inverting portion 12 while the space between the support member 13 and the cell 1 is sealed by a sealing material. The outer ends of the electrodes 3 and 4 are connected to the electrode contacts 14a, 14
The structure is such that the connection can be made alternately by the rotation of b and the contact reversing section 12.

The rotation of the contact reversing section 12 causes the electrode contacts 14
One of the electrodes 3 and 4 connected to “a” becomes a detection electrode, and a voltage is applied to the reference electrode 5 so as to have a predetermined potential. On the other hand, the electrode 3 connected to the electrode contact 14b,
The other one of 4 is a counter electrode. Also in the second embodiment, since the reference electrode 5 is used, the potential of the electrode serving as the detection electrode can be accurately detected by the voltmeter 6, and the control unit 11 controls the variable power supply unit 7 to output the voltmeter 6 to a predetermined value. Therefore, the potential for reducing residual chlorine is accurately applied to the detection electrode. Since the electrode contact 14a and the electrode contact 14b are connected to the variable power supply unit 7, when the liquid to be measured flows through the cell 1, an electrode reaction occurs at the detection electrode connected to the electrode contact 14a. The current flowing due to the reaction is detected by the current detection unit 8, and from the current value, the calculation unit 9 can calculate the residual chlorine concentration by conversion. As described above, the residual chlorine concentration measuring apparatus according to the second embodiment includes the support 1
By rotating the electrodes 3 and 4 integrally connected by 3, one electrode is connected to the electrode contact 14 a to serve as a detection electrode, and the other electrode is connected to the electrode contact 14 b and serves as a counter electrode. 4 can be used as a detection electrode to measure the residual chlorine concentration.

The electrode materials used for the electrodes 3 and 4 only need to be electrically equivalent. Electrode materials which form the same current density when the same potential is applied to the reference electrode 5 Is used. Regardless of which of the electrodes 3 and 4 is selected as the detection electrode, the same detection current can be obtained if the potentials with respect to the reference electrode 5 are equal. Is relatively free, and is not particularly limited.

By the way, if either the electrode 3 or the electrode 4 is connected to the electrode contact 14a without rotating the contact reversing section 12, and the electrode contact 14a is used for a long time as the detection electrode, the scale, slime, or other Ion components and the like adhere and contaminate, and the deterioration proceeds, making it difficult to obtain a predetermined current value, and making it impossible to detect a detection current with high accuracy. In such a state, the residual chlorine measuring apparatus according to the second embodiment rotates the contact reversing unit 12 to rotate the electrode contacts 14a, 14b.
By switching the connection of the electrodes 3 and 4 to be connected, the electrode used as the counter electrode is used as the detection electrode, the other electrode is changed from the detection electrode to the counter electrode, and the polarity of the applied voltage applied between the electrodes 3 and 4 is reversed. Good. As a result, the electrode switched from the counter electrode to the detection electrode is an electrode that has been washed by the oxidation reaction until immediately before, so that a low contamination state and a highly accurate and accurate detection current can be obtained. In addition, since the polarity of the applied voltage has been repeatedly inverted before use, contamination is not originally so advanced. Further, after that, a current in the opposite direction is caused to flow by using the electrode used as the detection electrode as a counter electrode, so that the surface of the electrode that has been contaminated up to that time can be cleaned by an oxidation reaction occurring on the surface. As described above, the electrodes 3 and 4 connected to the electrode contacts 14a and 14b are alternately switched by driving the contact inverting unit 12, and the electrodes 3 and 4 are alternately selected and used as the detection electrode and the counter electrode.
No. 4 contamination, a stable detection current can always be obtained, and accuracy in measurement can be improved.

The switching of the combination of the electrode contacts 14a, 14b and the electrodes 3, 4 by the contact inverting section 12 may be performed when the magnitude of the detection current of the electrodes 3, 4 selected as the detection electrodes drops. . The detection current drops because the adhesion of the scale or the like proceeds in proportion to the continuous energizing time. Therefore, by detecting the continuous energizing time of the variable power supply unit 7 provided between the electrodes 3 and 4, the application time is determined by a predetermined time. What is necessary is just to make the control part 11 switch the contact inversion part 12 when the time is exceeded.

In addition, in order to control the potential orientation of the pair of electrodes 3 and 4, a timer may be provided to control the contact inversion unit 12 by the control unit 11 at predetermined time intervals. The electrodes 3 and 4 can be switched by simpler means for detecting the continuous energization time, and contamination of the electrodes 3 and 4 can be prevented.

As described above, by alternately switching the contact inverting portions 12 to alternately invert the polarities of the electrodes 3 and 4,
The electrode selected as the detection electrode is always clean and can stably detect the detection current.The electrode can be washed and regenerated as the counter electrode, eliminating the need to pause for regeneration, enabling continuous detection and high accuracy. Residual chlorine concentration can be detected.

As described above, according to the embodiment of the present invention, the pair of electrodes are rotated by the contact inverting section, alternately inverted and connected to the two electrode contacts, and the detection electrode and the counter electrode are used alternately. With a simple device, deterioration of the electrode 3 can be prevented, the oxidation-reduction current can be measured easily and continuously, and a highly accurate residual chlorine concentration measuring device can be obtained.

[0042]

According to the first aspect of the present invention, the control unit switches the switch unit to select one of the pair of electrodes as the detection electrode and the other as the counter electrode, and invert the polarity of the applied voltage. The detection electrode can be alternately selected, the electrode is washed while the measurement is continued, the accuracy is improved, and continuous measurement is possible.

According to the second aspect of the present invention,
The pair of electrodes becomes electrically equivalent to each other, and can be accurately measured even if the polarity of the electrode applied to the electrodes is reversed.

According to the third aspect of the present invention,
After a predetermined continuous energizing time has elapsed, the detection electrodes are automatically inverted, so that the two electrodes are deteriorated to the same degree, and the electrodes are washed by the inversion to improve the accuracy, thereby enabling continuous measurement.

According to the invention described in claim 4 of the present invention,
When the timer measures a certain period of time, the detection electrodes are automatically inverted, so that the degree of contamination of the two electrodes can be made the same with a simple device, and the electrodes are washed by the inversion to improve the measurement accuracy. Then, continuous measurement becomes possible.

According to the invention described in claim 5 of the present invention,
The control unit drives the contact inversion unit to select one of the pair of electrodes as the detection electrode and the other as the counter electrode, and it is possible to invert the polarity of the applied voltage. While the electrode is cleaned, accuracy is improved and continuous measurement is possible.

According to the invention described in claim 6 of the present invention,
When the variable power supply unit energizes for a predetermined continuous energizing time, the detection electrodes are automatically inverted, so that the two electrodes are deteriorated to the same degree and the electrodes are cleaned by the inversion to improve the accuracy and enable continuous measurement. become.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a residual chlorine concentration measuring device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a residual chlorine concentration measuring device according to a second embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 cell 2a inlet tube 2b discharge tube 3,4 electrode 5 reference electrode 6 voltmeter 7 variable power supply unit 8 current detection unit 9 calculation unit 10 switch unit 11 control unit 12 contact inversion unit 13 support material 14a, 14b electrode contact

Claims (6)

[Claims] 1. A cell into which a liquid to be measured is introduced, a pair of electrodes and a reference electrode provided in the cell, and one of the pair of electrodes for detecting residual chlorine in the liquid to be measured. A switch unit that can select the other electrode as a counter electrode, a voltmeter that detects the potential of the detection electrode with respect to the reference electrode, and a voltage between the pair of electrodes to control the voltmeter to a predetermined voltage. A variable power supply unit, a control unit that inverts the polarity of a voltage applied between the pair of electrodes by the switch unit and alternately selects a detection pole, and an ammeter that detects a current value flowing through the detection pole. A residual chlorine concentration measuring device, comprising: a calculation unit for calculating a residual chlorine concentration from the current value. 2. The residual chlorine concentration measurement according to claim 1, wherein said pair of electrodes are made of an electrode material forming the same current density, and are arranged at the same distance from said reference electrode. apparatus. 3. The residual chlorine concentration measuring apparatus according to claim 1, wherein when the variable power supply unit supplies electricity for a predetermined continuous conduction time, the control unit switches the switch unit to invert the detection pole. . 4. The residual chlorine concentration measuring apparatus according to claim 1, wherein when the time measuring means measures a predetermined time, the control section switches the switch section to invert the residual chlorine concentration. 5. A cell into which a liquid to be measured is introduced, a pair of electrodes and a reference electrode provided in the cell, and one of the pair of electrodes for detecting residual chlorine in the liquid to be measured. A contact inverting portion that can be selected as a pole and the other as a counter electrode, a voltmeter that detects the potential of the detection electrode with respect to the reference electrode, and a voltage between the pair of electrodes to control the voltmeter to a predetermined voltage. A variable power supply section for adjusting; a control section for inverting the polarity of a voltage applied between the pair of electrodes by the contact inverting section to alternately select a detection pole; and an ammeter for detecting a current value flowing through the detection pole. A residual chlorine concentration measuring device, comprising: a calculation unit for calculating a residual chlorine concentration from the current value. 6. The residual chlorine concentration measurement according to claim 5, wherein when the variable power supply unit supplies electricity for a predetermined continuous conduction time, the control unit switches the contact inversion unit to invert the detection pole. apparatus.