JP2001235443A - Ph sensor and ion water generator with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain performance for a long time with an efficient maintenance of the pH sensor by detecting a drop in electromotive force and degrading of response as caused by the 1 adhesion of scale to a glass electrode part, clogging of a liquid junction and the like. SOLUTION: The pH sensor 100 has a cell 112 to which a liquid to be detected is supplied, a glass electrode part 102 which has a measuring electrode 14 arranged in a standard liquid held therein and is provided with a hydrogen ion sensitive glass film 101 to be dipped into the liquid in the cell 112, a reference electrode part 107 which has a reference electrode 106 arranged in an internal liquid 105 held therein and is provided with a liquid junction 108 to be dipped into the liquid in the cell 112, an arithmetic part 110 to calculate a pH value from an electromotive force generated between the measuring electrode 104 and the reference electrode 106 and a detection part 114 to detect the degrading of a sensor performance caused by inorganic or organic material adhering to the hydrogen ion sensitive glass film 101 and/or the liquid junction 108.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a pH sensor for measuring the pH of a solution and an ionic water generator having the same, and more particularly, to detecting a failure of the pH sensor.

[0002]

2. Description of the Related Art As shown in FIG. 7, a conventional pH sensor has a glass electrode 701 having a hydrogen ion sensitive film which is in contact with a test solution and generates an electric potential according to the hydrogen ion concentration thereof, and a p-type electrode.
An internal standard solution 702 containing an H buffer and a supporting salt, a measuring electrode consisting of a signal extraction electrode 703, a reference electrode generating a constant potential regardless of the internal solution 704 consisting of a supporting salt and the hydrogen ion concentration of the test solution. A container 706 for accommodating the internal liquid 705, the internal liquid 704, and the reference electrode 705, a reference electrode formed of a liquid junction 707 in contact with the test liquid and the internal liquid 704, and measuring a potential difference between the measurement electrode and the reference electrode. Measuring unit 7
08 and an arithmetic unit 709 for converting the potential difference into pH. When using such a pH sensor, p
A pH standard calibration solution having a specified concentration of 4.01, 6.86, and 9.18, respectively, is passed through the container 706 to measure the electromotive force generated between the glass electrode 701 and the measurement electrode.
Deterioration of sensor performance was determined based on whether or not this measured value was within the range of normal values.

[0003] In addition, the conventional pH sensor is mounted, and the pH of ionic water (electrolyzed water) generated by electrolyzing water is adjusted.
As an ionized water generator for controlling the H value, a Japanese Utility Model Laid-Open No. 5-22
No. 093 (hereinafter referred to as “A”) discloses a pH sensor for measuring the pH and flow rate of the generated alkaline water and acidic water, and an ion for controlling the drive voltage to the electrolytic device based on the sensor output ratio from the flow rate sensor. A water generator is disclosed.

Japanese Patent Application Laid-Open No. 5-64785 (hereinafter referred to as “B”) discloses a method in which a measured pH value of ionic water to be electrolyzed is compared with a preset pH value, and a deviation signal thereof is used. There has been proposed an ionic water generator for producing ionic water by controlling power supplied between electrodes for generating ionic water.

[0005]

However, the conventional p-type ion water generators disclosed in Japanese Patent Application Publication Nos.
The H sensor has the following problems.

(1) The pH sensor is placed under a severe condition that ionic water is continuously passed through.
The adhesion of poorly soluble inorganic substances such as calcium carbonate, magnesium carbonate, and silica contained in the electrolyzed ionic water and organic substances such as bacteria, as a pH sensor,
Since the performance such as responsiveness and stability is deteriorated, there is a problem that the pH value of the generated ionic water cannot be properly controlled.

(2) To solve such a problem, p
Although maintenance for periodically cleaning the H sensor has been proposed, since the method of detecting deterioration of the sensor performance using the pH standard calibration solution as described above is used, the frequency of use of the ion water generator is restricted, There was a problem that convenience was lost.

(3) The timing of cleaning the sensor portion to maintain the accuracy and stability is set based on the usage time of the pH sensor, the amount of water flow, and the like. There was a problem that it was necessary to increase the safety factor in order to deal with it, it was not efficient, there was no means to confirm the cleaning effect, and there was a possibility that the sensor could continue to be used even if the sensor performance deteriorated due to failure etc. .

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, detects deterioration in sensor performance such as accuracy, responsiveness, and stability, appropriately determines the timing of maintenance, and applies ion water generation to be applied. It is an object of the present invention to provide a pH sensor capable of improving the convenience of a vessel and an ion water generator including the same.

[0010]

According to the pH sensor of the present invention, a cell to which a test solution is supplied, and a measuring electrode arranged in a standard solution held therein are immersed in the test solution in the cell. A glass electrode portion provided with a hydrogen ion sensitive glass film, a reference electrode portion provided with a liquid junction immersed in a test solution in the cell in which a reference electrode is arranged in an internal liquid to be held, and the measurement electrode and the measurement electrode A calculation unit for calculating a pH value from an electromotive force generated between the reference electrode and a detection unit for detecting deterioration of sensor performance caused by attachment of an inorganic substance or an organic substance to the hydrogen ion sensitive glass film and / or the liquid junction; And is configured.

[0011] Thereby, the deterioration of the sensor performance such as accuracy, responsiveness, stability, etc. is detected, the maintenance timing is appropriately determined, and the pH of the ion water generator to be applied can be improved. A sensor and an ion water generator can be provided.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The pH sensor according to the first aspect of the present invention has a cell to which a test liquid is supplied, and a test liquid in the cell in which a measuring electrode is arranged in a standard solution held inside. A glass electrode portion having a hydrogen ion sensitive glass film immersed in a reference electrode portion having a liquid junction immersed in a test solution in the cell, wherein a reference electrode is disposed in an internal liquid to be held, PH from the electromotive force generated between the measurement electrode and the reference electrode
The calculation unit includes a calculation unit for calculating a value, and a detection unit for detecting deterioration in sensor performance caused by the attachment of an inorganic substance or an organic substance to the hydrogen ion sensitive glass film and / or the liquid junction.

As a result, the following effects can be obtained.

(A) By detecting the attachment of an inorganic substance or an organic substance to the hydrogen ion sensitive glass film and / or the liquid junction, and knowing the deterioration state of the sensor performance such as accuracy, responsiveness and stability caused by the detection. By performing maintenance such as washing, the pH value of the water to be treated can always be properly measured.

(B) The maintenance timing can be properly determined by using the detection unit, and the convenience of the applied ion water generator can be improved.

(C) Deterioration of the sensor performance due to adhesion of foreign substances to the hydrogen ion sensitive glass membrane and clogging of the liquid junction can be detected, so that efficient and accurate cleaning can be performed.

A pH sensor according to a second aspect is the pH sensor according to the first aspect, further comprising a voltage application unit that applies a DC voltage or an AC voltage between the measurement electrode and the reference electrode, wherein the detection unit is the voltage application unit. It is configured to measure DC resistance or AC impedance between the measurement electrode and the reference electrode using an applied voltage to be applied, and to detect deterioration of sensor performance by an initial value or a change amount from a previous measurement value. .

As a result, the following operation can be obtained in addition to the operation of the first aspect.

(A) Since the deterioration of the sensor performance is detected by measuring the DC resistance or AC impedance between the measurement electrode and the reference electrode, the state of the hydrogen-sensitive glass film and the liquid junction can be quickly evaluated when necessary. The pH value of the supplied test liquid can be accurately obtained.

(B) Since the DC resistance or the AC impedance is measured, the pH can be measured only by adding a simple electrical configuration.
A sensor can be configured, and the convenience related to maintenance can be improved at low cost.

According to a third aspect of the present invention, in the pH sensor according to the first aspect, a DC voltage or an AC voltage is applied between the application electrode disposed in the cell and the application electrode and the measurement electrode or the reference electrode. A voltage application unit, wherein the detection unit measures a DC resistance or an AC impedance between the application electrode and the measurement electrode or the reference electrode using an applied voltage applied by the voltage application unit, and an initial value or It is configured to detect the deterioration of the sensor performance based on the amount of change from the previous measurement value.

As a result, the following operation can be obtained in addition to the operation of the first aspect.

Since the performance deterioration of the glass electrode portion and the performance deterioration of the liquid junction portion can be individually detected, a maintenance method such as cleaning corresponding to each portion can be selected, and more efficient cleaning can be performed.

According to a fourth aspect of the present invention, there is provided a pH sensor according to any one of the first to third aspects, further comprising an electric conductivity measuring unit for measuring the electric conductivity of the test liquid, wherein the detecting unit is configured to detect the DC resistance or the DC resistance. It is configured to detect deterioration of sensor performance using a correction value obtained by subtracting the contribution of the electrical conductivity from the value of the AC impedance.

Thus, the following operation is obtained in addition to the operation of any one of the first to third aspects.

Since the value of the DC resistance or the AC impedance is corrected using the conductivity of the test solution, the performance of the sensor caused by the adhesion of foreign matter to the hydrogen-sensitive glass film of the glass electrode and the clogging of the liquid junction of the reference electrode is reduced. Deterioration can be more accurately detected.

According to a fifth aspect of the present invention, there is provided a pH sensor according to the first aspect, further comprising a storage unit capable of holding the test liquid in the cell for a predetermined time, wherein the detection unit is provided in the storage unit. It is configured to detect the deterioration of the sensor performance based on the amount of change in the conductivity of the test solution.

As a result, the following operation can be obtained in addition to the operation of the first aspect.

(A) By measuring the value of the electric conductivity of the test liquid stored in the storage unit for a certain period of time, it is possible to easily detect the clogging of the liquid junction from the change in the measured value.

(B) In addition to the adhesion of inorganic substances such as calcium carbonate, magnesium carbonate, and silica in the test liquid and the organic substances such as bacteria, the clogging of the liquid junction portion is caused by the drying of the liquid junction and the fixing of the supporting salt in the internal liquid. Therefore, it is likely to occur earlier than the performance deterioration of the glass electrode portion using the hydrogen-sensitive glass film. By detecting the state of deterioration of the liquid junction, which is considered to be the main cause of such sensor performance deterioration, maintenance of the pH sensor can be performed accurately and promptly.

A pH sensor according to a sixth aspect of the present invention includes a storage unit for storing a response waveform of the electromotive force generated when the measurement electrode and the reference electrode are immersed in the test solution according to the first aspect, The detection unit is configured to detect a deterioration in sensor performance based on an initial slope change of the response waveform stored in the storage unit.

Thus, in addition to the function of the first aspect, the following function can be obtained.

(A) Since the required pH measurement can be performed after directly confirming the response of the pH sensor, the measurement can always be performed under appropriate conditions.

(B) Since the storage unit for storing the data of the responsiveness of the pH sensor is provided, it is possible to grasp the temporal change of the deterioration state and perform the maintenance management with good visibility in a proper manner.

According to a seventh aspect of the present invention, in the pH sensor according to the first aspect, a drift of a response waveform of the electromotive force generated when the detection unit immerses the measurement electrode and the reference electrode in the test solution. It is configured to detect a deterioration in sensor performance due to a change in the amount.

Thus, in addition to the function of the first aspect, the following function can be obtained.

Since the stability as a pH sensor is directly detected, performance degradation can be accurately detected.

[0038] The pH sensor according to claim 8 includes, in claim 1, a light emitting unit for irradiating the hydrogen ion sensitive glass film with light, and a light receiving unit for receiving the light emitted from the light emitting unit. The detection unit is configured to detect the performance deterioration of the glass electrode unit based on a change in the amount of light received by the light receiving unit.

Thus, the following operation can be obtained in addition to the operation of the first aspect.

(A) Adhesion of inorganic substances such as calcium carbonate, magnesium carbonate and silica in the test liquid and organic substances such as bacteria to the glass electrode can be directly detected optically.

(B) Since no current is applied to the test solution, p is maintained without electrochemically disturbing the state of the test solution.
The deterioration state of the H sensor can be detected.

A ninth aspect of the present invention is the pH sensor according to the eighth aspect, wherein the light emitted from the light emitting section includes an ultraviolet ray.

Thus, in addition to the function of claim 8, the following function can be obtained.

Organic substances and bacteria, which are one of the causes of performance deterioration of the hydrogen ion-sensitive glass membrane, are killed by the irradiation of ultraviolet rays. Therefore, their adhesion can be effectively prevented, and the number of maintenance of the pH sensor can be reduced. Can be.

According to a tenth aspect of the present invention, in the ionic water generator provided with the pH sensor, an electrolytic cell for electrolyzing supplied water into ionic water having a predetermined pH value is provided, and the ionic water generator is disposed in a drain passage of the electrolytic cell. The pH sensor according to any one of 1 to 9, and a sensor cleaning unit for cleaning the pH sensor are provided. Thereby, the following operation is obtained. (A) Since the performance of the pH sensor can be properly maintained, the pH value of the discharged ionic water can be accurately controlled.

(B) Deterioration of sensor performance such as accuracy, responsiveness, and stability is detected, maintenance timing is appropriately determined, and the convenience of the applied ion water generator can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a configuration diagram of a pH sensor according to Embodiment 1 of the present invention.

In FIG. 1, reference numeral 100 denotes p in the first embodiment.
H sensor, 101 is a hydrogen ion sensitive glass film that generates an electric potential depending on the hydrogen ion concentration, 102 is a glass electrode part provided with the hydrogen ion sensitive glass film 101, 103 is a standard solution containing a pH buffer solution and a supporting salt, 104 is calomel Electrode, P
A measurement electrode for signal extraction provided with a t electrode, an Ag / AgCl electrode, etc., 105 is an internal solution in which a supporting salt is dissolved, 1
Reference numeral 06 denotes a reference electrode for generating a constant potential irrespective of the hydrogen ion concentration of the test solution, reference numeral 107 denotes a reference electrode portion containing the internal solution 105 and the reference electrode 106, and reference numeral 108 denotes a contact between the test solution and the internal solution 105. A liquid junction for giving continuity, 109 is a potential measuring unit for measuring a potential difference between the measuring electrode 104 and the reference electrode 106, 110 is a computing unit for converting the potential difference detected by the potential measuring unit 109 to pH, and 111 is a calculating unit. Temperature sensor consisting of a thermocouple, etc. for measuring the water temperature of the test liquid, 1
Reference numeral 12 denotes a cell for holding a test solution, and 113 denotes a measurement electrode 104.
And a voltage application unit for supplying a DC voltage or an AC voltage to the reference electrode 106, a detection unit 114 for detecting the deterioration of the pH sensor, and a hydrogen ion sensitive glass film 101 disposed in the detection unit 114. A measuring unit 116 for measuring the DC resistance or AC impedance of the liquid junction 108, and a storage unit 116 for storing the measured values arranged in the detecting unit 114.

The hydrogen ion sensitive glass film 101 is a glass film that comes into contact with the test solution and generates an electric potential depending on the hydrogen ion concentration. The material is mainly composed of silica (SiO ₂ ), sodium (Na), lithium ( Li) and the like. Here, barium (Ba), cesium (Cs), calcium (Ca) may be added to reduce alkali errors, and lanthanum (La) may be added to provide chemical stability.

The glass electrode section 102 includes a hydrogen ion sensitive glass film 101, a measurement electrode 104, and a standard solution 103. In addition, an inorganic material such as glass or ceramic or an insulating material such as a plastic material such as polyvinyl chloride or a fluororesin is used for a portion of the glass electrode portion 102 that holds the hydrogen ion-sensitive glass film 101; It is desirable to use a plastic having no light transmission property.

The standard solution 103 is an internal standard solution containing a pH buffer and a supporting salt. Normally, a neutral phosphate (pH 6.86) is used as the pH buffer, but a phthalate (p
H4.01), borate (pH 9.18), carbonate (p
H10.01) may be used. As the supporting salt, chloride, particularly high concentration KCl of 3.3 mol / L or more is used.

As the measuring electrode 104, a calomel electrode, a Pt electrode, or an Ag / AgCl electrode having high electrical stability is used. At present, the Ag / AgCl electrode is generally used in terms of safety and cost. Further, in order to maintain the long-term stability of Ag / AgCl, it is desirable that the material be coated with fluorine or the like which has excellent chemical stability.

The supporting salt contained in the internal solution 105 includes:
Chloride, especially a high-concentration KCl solution of 3.3 mol / L or more is used. However, glycerin is added to a gelling agent such as agar or gelatin to suppress the outflow of the internal solution, stabilize, and prevent crystallization of the supporting salt. Alternatively, an internal liquid is added to and mixed with a water evaporation inhibitor such as propylene alcohol, and a gel internal liquid or a cellulosic viscous agent such as carboxymethyl cellulose or hydroxyethyl cellulose or an acrylamide polymer is added to the internal liquid. A gel-like internal liquid is also used.

The reference electrode 106 is for generating a constant potential irrespective of the hydrogen ion concentration of the test solution, and is a highly electrically stable calomel electrode, Pt electrode, Ag / Ag
Although a Cl electrode is used, an Ag / AgCl electrode is generally used at present in terms of safety and cost. Also,
In order to maintain the long-term stability of Ag / AgCl, those coated with fluorine or the like having excellent chemical stability are desirable.

The reference electrode unit 107 has a reference electrode 106, an internal liquid 105, and a liquid junction 108. Each component of the reference electrode unit 107 has a structure supported by an insulating material made of an inorganic material such as glass or ceramic, or a plastic material such as polyvinyl chloride, fluororesin, or ABS resin.

The liquid junction 108 is a portion which is in contact with the test liquid and the internal liquid 105 and serves as a conductive path for electrically connecting the reference electrode 106 and the test liquid. A porous polymer such as a porous polyester, a porous acrylic or the like, an alumina-based, silica-based or gyricon-based ceramic having water absorption is used,
It is desirable to coat with a water repellent such as silicon or a fluorine compound in order to stabilize the outflow of the internal liquid.

The potential measuring section 109 measures the potential difference between the measuring electrode 104 and the reference electrode 106.

The calculation unit 110 is a device such as a computer for converting the potential difference detected by the potential measurement unit 109 into pH.

As the temperature sensor 111, a thermocouple is usually used. The data of the water temperature measured by the temperature sensor 111 is sent to the arithmetic unit 110, and is used for correcting an error at the time of pH conversion.

The voltage applying unit 113 supplies a DC voltage or an AC voltage to the measuring electrode 104 and the reference electrode 106.

The detection unit 114 is a hydrogen ion sensitive glass film 1
A measuring unit 115 for measuring a DC resistance or an AC impedance between the liquid crystal 01 and the liquid junction 108 and a storage unit 116 for storing the measured value are provided. The DC resistance of the hydrogen ion sensitive glass film 101 and the liquid junction 108 stored in the storage unit 116 is provided. Alternatively, the deterioration of the pH sensor 100 can be detected by comparing the initial value or the previous measurement value of the AC impedance with the current measurement value.

Next, the pH sensor 100 having the above configuration
The operation and the operation of will be described.

In FIG. 1, the test liquid in the cell 112 is
When the hydrogen ion sensitive glass film 101 of the pH sensor 100 comes into contact with the liquid junction 108, the hydrogen ion sensitive glass film 101
Is the pH of the standard solution 103 and the p of the test solution on both sides of the membrane.
An H-dependent electromotive force is generated. The potential of the measurement electrode 104 changes due to the electromotive force. In contrast, the internal liquid 10
5, the reference electrode 106 generates a constant potential independent of the pH of the test solution.
6, a potential difference is generated between the potential measurement units 109
Is detected by The detected potential difference is calculated by the arithmetic unit 110
Is converted to pH. At this time, the temperature sensor 111
The data of the water temperature measured in is sent to the arithmetic unit 110,
Used for error correction during pH conversion. Here, the pH value is expressed by Nernst equation: pHx = pHs + (Es-Ex) F / R
According to Tln10, about 59 mV / pH at 25 ° C.

PHx: pH of the test solution pHs: known pH Ex: electromotive force at the time of measurement of the test solution Es: electromotive force at the time of known pH measurement F: Faraday constant 96485 (C / mol) R: gas constant 8.314 (J / mol / K) T: thermodynamic temperature (K) Here, a DC or AC voltage is supplied between the measurement electrode 104 and the reference electrode 106 by the voltage application unit 113 before and after the start of the measurement or every use time. The DC resistance or the AC impedance is measured by the measuring unit 115.

The measured value is compared with the initial value stored in the storage unit 116 or the previous measured value, and if the variation does not fall within the normal value, the detecting unit 114 detects deterioration in sensor performance.

That is, when the DC resistance and the AC impedance increase, an inorganic substance such as calcium carbonate or an organic substance such as bacteria adheres to the hydrogen ion sensitive glass film 101;
Alternatively, clogging due to attachment of an inorganic substance such as calcium carbonate or an organic substance such as bacteria to the liquid junction 108 may be considered. Thus, a reduction in electromotive force, deterioration in stability, and a delay in response time occur.

When the DC resistance and the AC impedance decrease, the insulation between the hydrogen ion sensitive glass film 101 and the glass electrode part 102 is deteriorated, and the hydrogen ion sensitive glass film
01 may be damaged, the electromotive force decreases, the stability deteriorates,
Delay in response time occurs. In particular, when the hydrogen ion sensitive glass film 101 is damaged, no electromotive force may be generated.

As described above, when the DC resistance and the AC impedance rise and an abnormality is detected, the sensor is automatically or manually washed. When the DC resistance and the AC impedance decrease and the abnormality is detected, the sensor is replaced. it can.

Since the pH sensor 100 according to the first embodiment is configured as described above, it has the following operation.

(1) By detecting the attachment of an inorganic substance or an organic substance to the hydrogen ion sensitive glass film and / or the liquid junction, and knowing the deterioration state of the sensor performance such as accuracy, responsiveness and stability caused by the detection. By appropriately performing maintenance such as washing, the pH value of the water to be treated can be properly measured.

(2) Deterioration of the sensor performance due to adhesion of foreign substances to the hydrogen ion sensitive glass membrane or clogging of the liquid junction can be detected, so that efficient and accurate cleaning can be performed.

(Embodiment 2) FIG. 2 shows a configuration diagram of a pH sensor according to Embodiment 2 of the present invention. In FIG. 2, the same reference numerals as in FIG. 1 denote the first embodiment.
Since it has basically the same operation as that of the first embodiment, a detailed description is omitted as it is in the description of the first embodiment.

Reference numeral 200 denotes the pH sensor according to the second embodiment,
Reference numeral 01 denotes an application electrode provided in the cell 112 holding the test liquid, and reference numeral 202 denotes a conductivity measuring unit provided with a conductivity meter for measuring the conductivity of the test liquid. In addition, the conductivity measuring unit 2
By providing 02 in a storage unit (not shown) in the cell 112, it is possible to keep the test liquid for a certain period of time and measure the conductivity more stably.

The data of the conductivity of the test solution measured by the conductivity measuring unit 202 is sent to the detecting unit 114, and the DC resistance or the AC impedance is calculated and used for error correction.

Since the pH sensor according to the second embodiment is configured as described above, it has the following operation.

(1) Before or after the start of the measurement, or at every use time, the DC or DC voltage is applied between the measurement electrode 104 and the application electrode 201, between the reference electrode 106 and the application electrode 201, or between the measurement electrode 104 and the reference electrode 106 by the voltage application unit 113. An AC voltage is supplied, and the DC resistance or AC impedance between them can be measured by the measuring unit 115.

(2) The conductivity of the test solution is measured by the conductivity measuring unit 202, and the value obtained by subtracting the influence of the test solution from the measured DC resistance or AC impedance between each is stored in the storage unit 116. If the change amount does not fall within the normal value as compared with the initial value or the previous value, the detecting unit 11
4 can detect performance degradation.

(3) When an inorganic substance such as calcium carbonate or an organic substance such as bacteria adheres to the hydrogen ion sensitive glass film 101, an increase or decrease in DC resistance or AC impedance can be individually detected, and maintenance corresponding to each of them can be performed. be able to.

(4) Here, the amount of change in the conductivity of the test solution over a certain period of time by the conductivity measuring unit 202 is measured stably for the test solution stored in the storage unit and the like, and stored in the storage unit 116. If the change amount is not within the normal value after being compared with the initial value or the previous value,
Performance degradation due to clogging can be detected.

(Embodiment 3) FIG. 3 shows a configuration diagram of a pH sensor according to Embodiment 3 of the present invention. In FIG. 3, the same reference numerals as in FIG. 1 denote the first embodiment.
Since it has basically the same operation as that of the first embodiment, a detailed description is omitted as it is in the description of the first embodiment.

In FIG. 3, reference numeral 300 denotes p of the third embodiment.
H sensor, 301 is a detection unit, 302 is a response waveform measurement unit, and 303 is a response waveform storage unit.

Next, the operation and operation of the pH sensor 300 according to the third embodiment will be described. The response waveform of the electromotive force generated between the measurement electrode 104 for signal extraction and the reference electrode 106 is measured by the response waveform measurement section 302. . The response waveform is
The waveform depending on the state of the hydrogen ion sensitive glass membrane 101 before measurement, the pH of the test solution, and the performance of the pH sensor is shown. FIG. 4 is a graph showing an example of a response waveform of the electromotive force.

Since the pH sensor 300 of the third embodiment is configured as described above, it has the following operation.

The response waveform is predicted from the initial or previous response waveform stored in the response waveform storage unit 303, and the slope or drift value of the measured response waveform is compared. At 301, performance degradation is detected. Here, the hydrogen ion sensitive glass membrane 1 before measurement
Since the state of 01 depends on the pH value measured last time,
By measuring the test liquid after measuring the known pH, the response waveform of the electromotive force can be more accurately predicted.

(Embodiment 4) FIG. 5 shows a configuration diagram of a pH sensor according to Embodiment 4 of the present invention. In FIG. 5, the same reference numerals as in FIG. 1 denote the first embodiment.
Since it has basically the same operation as that of the first embodiment, a detailed description is omitted as it is in the description of the first embodiment. 500 is the pH sensor of Embodiment 4, 501 is a light emitting unit, 502 is a light receiving unit,
Reference numeral 503 denotes a detection unit, and 504 denotes a storage unit.

Next, the operation and action of the pH sensor 500 according to the fourth embodiment will be described. Light emitted from the light emitting portion 501 to the hydrogen ion sensitive glass film 101 is caused by inorganic and organic substances adhering to the hydrogen ion sensitive glass film 101. After being absorbed and attenuated and transmitted through the hydrogen ion sensitive glass film 101, the light is received by the light receiving unit 502. The intensity of the received light is compared with the initial value or the previous value stored in the storage unit 504, and if the intensity does not fall within the normal value, the performance deterioration is detected by the detection unit 503. Here, since ultraviolet rays have a function of decomposing organic substances and can suppress performance deterioration and organic substance adhesion, it is desirable that the light irradiated to the hydrogen ion sensitive glass film 101 contains ultraviolet rays.

The pH sensor 500 according to the fourth embodiment has the following operation because it is configured as described above.

(A) Since no current is applied to the test solution, p
The deterioration state of the H sensor can be detected.

(B) Organic substances and bacteria, which are one of the causes of performance deterioration of the hydrogen ion sensitive glass membrane, are killed by the irradiation of ultraviolet rays, so that their adhesion can be effectively prevented.
The number of maintenance of the H sensor can be reduced.

(Embodiment 5) FIG. 6 shows a configuration diagram of an ion water generator mounted in the pH sensor of the present invention.
6, reference numeral 600 denotes an ion water generator according to the sixth embodiment; 601, a raw water pipe such as tap water; 602, a faucet;
Reference numeral 4 denotes a water purification section having an activated carbon or hollow fiber membrane inside,
Reference numeral 5 denotes a mineral addition unit for adding minerals to raw water to increase electric conductivity, 606 a flow sensor for confirming water flow, and instructing a controller unit to start control, which will be described later. Decomposing electrolytic cell, 6
08 is a diaphragm which divides the electrolytic cell 607 into two, 609 and 610 are electrode plates arranged in each electrolysis chamber divided into two by the diaphragm 608,
Reference numeral 611 denotes a discharge tube for discharging water on the electrode plate 609 side (alkaline ionized water when the electrode plate 609 is a cathode), and 612 denotes a pH detection chamber branched from the discharge tube 611 to detect performance deterioration of the present invention. A pH sensor 613 having a function is attached. 614 is a pH sensor 613 for washing liquid.
615 is a sensor cleaning unit for supplying to the electrode plate 61
Water on the 0 side (acidic water when the electrode plate 610 is the anode) and pH
A drain pipe for discharging water that has passed through the detection chamber 612, 616 is a solenoid valve for draining residual water in the electrolytic tank 607 and electrode cleaning water in which scale has been dissolved during electrode cleaning, and 617 is a drain pipe 615 and a solenoid valve. A discharge pipe for discharging the wastewater from 616,
Reference numeral 619 denotes a power supply unit for converting an alternating current from the power supply plug 618 to direct current, 620 a controller unit for controlling the operation of the ion water generator 600, and 621 a display of an operation state of the ion water generator 600 to set operation conditions and the like. Display section for the operation.

Next, the ionized water generator 60 according to the fifth embodiment will be described.
The operation and operation of 0 will be described. Raw water passed through the raw water pipe 601 through the faucet 602 removes impurities such as residual chlorine odor and general bacteria in the raw water in the water purification unit 604, and dissolves minerals such as calcium glycerophosphate in the mineral supply unit 605 to perform electrolysis. After being processed into easy water, the water is passed through a flow rate sensor 606 to an electrolytic cell 607. On the other hand, an AC voltage is applied from a power-on plug 618, converted into DC by a power supply unit 619, and then supplied to the electrode plates 609 and 610 of the electrolytic cell 607. Thereby, acidic ion water is generated in the anode chamber, and alkaline ion water is generated in the cathode chamber. At this time, when a voltage is applied so that the electrode plate 609 has a negative voltage, alkaline ionized water is obtained from the discharge pipe 611, and when a voltage is applied so as to have a positive voltage, acidic ionized water is obtained. Part of the discharge water is passed through a pH detection chamber 612 branched from the discharge pipe 611, and the pH concentration is measured by a pH sensor 613. The measured value is sent to the controller unit 620 and compared with the target pH value.
Electrolysis voltage, water flow, and the like are controlled so as to reach the target pH. pH sensor 613 includes calcium carbonate in the test solution,
Since the performance gradually deteriorates due to the adhesion of inorganic substances such as magnesium carbonate and silica and organic substances such as bacteria, accurate measurement cannot be performed. When the deterioration of the sensor performance is detected electrochemically or optically, the controller 620 supplies a cleaning liquid from the sensor cleaning unit 614 to the pH sensor 613 to perform cleaning. Here, the cleaning solution may be a chemical such as citric acid. However, the strong acid water generated in the electrolytic cell 607 is effective in terms of handling safety and removing both inorganic and organic substances. desirable. Also, pH
By providing an ultrasonic vibrator in the detection chamber 612, cleaning is promoted, and cleaning and removal can be performed in a short time. When the damage of the pH sensor 613 is electrochemically detected, it is transmitted to the controller unit 620, and the operation display unit 621 displays the replacement of the pH sensor. Since the pH measurement water and the pH sensor cleaning water pass through the drain pipe 615 together with the water on the electrode plate 610 side and are discharged from the water discharge pipe 617, it is safe even if the pH sensor 613 is damaged.

Since the ionic water generator of the fifth embodiment is configured as described above, the performance of the pH sensor 613 can be maintained properly, the pH value of the ionic water to be discharged can be controlled accurately, and the accuracy can be improved. In addition, by detecting deterioration of sensor performance such as responsiveness and stability, the timing of maintenance can be appropriately determined, and the convenience of the applied ion water generator can be improved.

[0094]

According to the pH sensor according to the first aspect of the present invention, the following effects can be obtained.

(A) By detecting the attachment of an inorganic substance or an organic substance to the hydrogen ion sensitive glass film and / or the liquid junction, and knowing the deterioration state of the sensor performance such as accuracy, responsiveness, and stability caused by the detection. By performing maintenance such as washing, the pH value of the water to be treated can always be properly measured.

(B) The timing of maintenance can be properly determined by using the detection unit, and the convenience of the ion water generator to which the present invention is applied can be improved.

(C) Deterioration of sensor performance due to adhesion of foreign substances to the hydrogen ion sensitive glass membrane or clogging of the liquid junction can be detected, so that efficient and accurate cleaning can be performed.

According to the pH sensor according to the second aspect,
As a result, the following effects can be obtained in addition to the effects of the first aspect.

(A) Since the deterioration of the sensor performance is detected by measuring the DC resistance or the AC impedance between the measurement electrode and the reference electrode, the state of the hydrogen-sensitive glass film and the liquid junction can be quickly evaluated when necessary. The pH value of the supplied test liquid can be accurately obtained.

(B) Since the DC resistance or the AC impedance is measured, the pH can be measured only by adding a simple electrical configuration.
A sensor can be configured, and the convenience related to maintenance can be improved at low cost.

According to the pH sensor according to the third aspect,
As a result, the following effects can be obtained in addition to the effects of the first aspect.

Since the performance deterioration of the glass electrode portion and the performance deterioration of the liquid junction portion can be individually detected, a maintenance method such as cleaning corresponding to each portion can be selected, and more efficient cleaning can be performed.

According to the pH sensor according to the fourth aspect,
Thereby, the following effects can be obtained in addition to the effects of any one of the first to third aspects.

Since the value of the DC resistance or the AC impedance is corrected using the electric conductivity of the test solution, the sensor performance caused by the adhesion of foreign matter to the hydrogen-sensitive glass film of the glass electrode and the clogging of the liquid junction of the reference electrode is reduced. Deterioration can be more accurately detected.

According to the pH sensor according to the fifth aspect,
As a result, the following effects can be obtained in addition to the effects of the first aspect.

(A) Clogging of the liquid junction can be easily detected by a change in the value of the electric conductivity of the test liquid stored in the storage section for a certain period of time.

(B) In addition to the adhesion of inorganic substances such as calcium carbonate, magnesium carbonate, and silica in the test solution and the organic matter such as bacteria, the clogging of the liquid junction portion and the adhesion of the supporting salt in the internal solution due to the drying of the liquid junction. Therefore, it is likely to occur earlier than the performance deterioration of the glass electrode portion using the hydrogen-sensitive glass film. By detecting the state of deterioration of the liquid junction, which is considered to be the main cause of such sensor performance deterioration, maintenance of the pH sensor can be performed accurately and promptly.

According to the pH sensor according to the sixth aspect,
As a result, the following effects can be obtained in addition to the effects of the first aspect.

(A) Since the necessary pH measurement can be performed after directly checking the response of the pH sensor, the measurement can always be performed under appropriate conditions.

(B) Since the storage unit for storing the data of the responsiveness of the pH sensor is provided, it is possible to grasp the temporal change of the deterioration state and to appropriately perform the maintenance management with good visibility.

According to the pH sensor according to the seventh aspect,
As a result, the following effects can be obtained in addition to the effects of the first aspect.

Since the stability as a pH sensor is directly detected, performance degradation can be accurately detected.

According to the pH sensor according to the eighth aspect,
As a result, the following effects can be obtained in addition to the effects of the first aspect.

(A) Adhesion of inorganic substances such as calcium carbonate, magnesium carbonate and silica in the test liquid and organic substances such as bacteria to the glass electrode can be directly detected optically.

(B) Since no electric current is applied to the test solution, p is maintained without electrochemically disturbing the state of the test solution.
The deterioration state of the H sensor can be detected.

According to the pH sensor according to the ninth aspect,
As a result, the following effect can be obtained in addition to the effect of the eighth aspect.

Organic substances and bacteria, which are one of the causes of deterioration of the performance of the hydrogen ion sensitive glass membrane, are killed by the irradiation of ultraviolet rays, so that their adhesion can be effectively prevented, and the number of maintenance of the pH sensor can be reduced. it can.

According to the ionic water generator provided with the pH sensor according to the tenth aspect, the following effects can be obtained.

(A) Since the performance of the pH sensor can be maintained properly, the pH value of the discharged ionic water can be accurately controlled.

(B) Deterioration of sensor performance such as accuracy, responsiveness, and stability can be detected, maintenance timing can be appropriately determined, and the convenience of the applied ion water generator can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a pH sensor according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a pH sensor according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a pH sensor according to a third embodiment of the present invention.

FIG. 4 is a graph showing an example of a response waveform of an electromotive force.

FIG. 5 is a configuration diagram of a pH sensor according to a fourth embodiment of the present invention.

FIG. 6 is a configuration diagram of an ion water generator including a pH sensor according to a fifth embodiment of the present invention.

FIG. 7 is a configuration diagram of a conventional pH sensor.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 pH sensor 101 hydrogen ion sensitive glass membrane 102 glass electrode section 103 standard solution 104 measurement electrode 105 internal solution 106 reference electrode 107 reference electrode section 108 liquid junction 109 potential measurement section 110 calculation section 111 temperature sensor 112 cell 113 voltage application section 114 detection Unit 115 Measurement unit 116 Storage unit 200 pH sensor 201 Applied electrode 202 Conductivity measurement unit 300 pH sensor 301 Detection unit 302 Response waveform measurement unit 303 Response waveform storage unit 500 pH sensor 501 Light emission unit 502 Light reception unit 503 Detection unit 504 Storage unit 600 Ionized water generator 601 Raw water pipe 602 Water faucet 604 Water purification section 605 Mineral addition section 606 Flow rate sensor 607 Electrolytic tank 608 Diaphragm 609 Electrode plate 610 Electrode plate 611 Discharge tube 612 pH detection chamber 613 p Sensor 614 Sensor cleaning part 615 Drain pipe 616 Solenoid valve 617 Water discharge pipe 618 Power supply plug 619 Power supply part 620 Controller part 621 Operation display part 701 Glass electrode 702 Internal standard liquid 703 Signal extraction electrode 704 Internal liquid 705 Reference electrode 706 Container 707 Liquid junction 708 Measurement unit 709 Operation unit

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hirofumi Nakamura 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd.

Claims (10)

[Claims] 1. A cell to which a test solution is supplied, and a glass electrode section having a hydrogen ion sensitive glass film in which a measurement electrode is disposed in a standard solution held therein and immersed in the test solution in the cell. And a reference electrode portion provided with a liquid junction immersed in the test liquid in the cell in which the reference electrode is disposed in the internal liquid to be held, and p from an electromotive force generated between the measurement electrode and the reference electrode.
A pH sensor comprising: a calculation unit for calculating an H value; and a detection unit for detecting deterioration in sensor performance caused by the attachment of an inorganic substance or an organic substance to the hydrogen ion sensitive glass film and / or the liquid junction. . And a voltage application section for applying a DC voltage or an AC voltage between the measurement electrode and the reference electrode, wherein the detection section uses the applied voltage applied by the voltage application section to apply a voltage between the measurement electrode and the reference electrode. The pH sensor according to claim 1, wherein a DC resistance or an AC impedance between the electrodes is measured, and deterioration of the sensor performance is detected based on an initial value or a change amount from a previous measured value. 3. An electrode disposed in the cell, and a voltage application unit for applying a DC voltage or an AC voltage between the application electrode and the measurement electrode or the reference electrode, wherein the detection unit is configured to detect the voltage. DC resistance or AC impedance between the applied electrode and the measuring electrode or the reference electrode is measured using an applied voltage applied by an applying unit, and deterioration of sensor performance is determined by an initial value or a change amount from a previous measured value. The pH according to claim 1, wherein the pH is detected.
sensor. 4. An electric conductivity measuring unit for measuring electric conductivity of the test liquid, wherein the detecting unit uses a correction value obtained by subtracting a contribution of the electric conductivity from the value of the DC resistance or the AC impedance. The pH sensor according to any one of claims 1 to 3, wherein deterioration of the sensor performance is detected. 5. A storage unit capable of holding a test liquid in the cell for a certain period of time, wherein the detection unit deteriorates sensor performance due to a change in conductivity of the test liquid held in the storage unit. The pH according to claim 1, wherein the pH is detected.
sensor. 6. A storage unit for storing a response waveform of the electromotive force generated when the measurement electrode and the reference electrode are immersed in the test solution, wherein the detection unit stores the response waveform stored in the storage unit. The pH sensor according to claim 1, wherein deterioration of the sensor performance is detected based on a change in an initial slope of the waveform. 7. The sensor according to claim 1, wherein the detecting unit detects deterioration in sensor performance based on a change in a drift amount of a response waveform of the electromotive force generated when the measurement electrode and the reference electrode are immersed in the test solution. The pH sensor according to claim 1, wherein: 8. A light-receiving section for irradiating the hydrogen ion-sensitive glass film with light, and a light-receiving section for receiving light emitted from the light-emitting section, wherein the detecting section detects the amount of light received by the light-receiving section. The pH sensor according to claim 1, wherein the performance deterioration of the glass electrode part is detected by a change in the pH value. 9. The pH sensor according to claim 8, wherein the light emitted from the light emitting section includes an ultraviolet ray. 10. An electrolytic cell for electrolyzing supplied water into ionic water having a predetermined pH value, a pH sensor according to any one of claims 1 to 9, which is disposed in a drainage channel of the electrolytic cell.
An ion water generator provided with a pH sensor, further comprising a sensor washing unit for washing the pH sensor.