JPH07209231A - Apparatus for measuring concentration of chlorine - Google Patents

Abstract

PURPOSE:To provide an apparatus for measuring the concent ration of chlorine at a level of pH 2 or thereabout accurately. CONSTITUTION:The apparatus for measuring the concentration of chlorine comprises a post-electrolysis conductivity meter 35, an A/D conversion circuit 51 for converting the conductivity value thus measured into a digital data, a circuit 56 for amplifying the electrolytic current flowing between the electrodes 31c, 31d disposed in an electrolytic cell 31 using the electrolytic voltage from an electrolytic power supply 32, an A/D conversion circuit 53 for converting the output value from the amplifying circuit 56 into a digital data, and a CPU 42 for receiving data from the A/D conversion circuits 51, 53 and determining the concentration of chlorine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chlorine concentration measuring device, for example, used in a strongly acidic water generator for producing strongly acidic water having a high bactericidal effect by electrolyzing mixed water of tap water and saline. To be done. Strongly acidic water means, for example, generated water obtained by electrolyzing tap water having a pH of 7 and residual chlorine concentration of 0.3 to 0.8 ppm is around pH 2, redox potential of 1100 to 1400 mV and residual chlorine concentration of 20 to 50 p.
It is about pm.

[0002]

2. Description of the Related Art Conventionally, a pH meter or ORP (oxidation reduction potential) is used to measure the degree of chlorine concentration.
) Pseudo measurement is performed using a meter. These measuring instruments measure using chemical reactions. That is, a measurement solution of potassium chloride (KCl) is filled inside,
This filled measurement liquid oozes into the generated water,
The chemical reaction at this time is the voltage change between both electrodes (ie,
It is measured as a change in current).

[0003]

However, in such a pH meter or ORP meter, the relationship between the pH value to be measured and the current value is logarithmic as shown in FIG. Therefore, especially at a high pH value (that is, near pH 2), the pH value hardly changes with respect to the change of the current value. For example, even if the current value changes from 30 A to 50 A, the pH value hardly changes, and the state stops at the order of pH 2.2. In other words, a difference of about 0.1 in pH value at this level is
In the P meter, the error range is reached.

As described above, in the conventional pH meter ORP meter,
There has been a problem that the measurement accuracy sharply decreases as the pH approaches 2, which indicates strong acidity. The present invention was devised to solve such problems, and its purpose is p
An object of the present invention is to provide a chlorine concentration measuring device capable of indirectly and accurately measuring the chlorine concentration at a level around H2.

[0005]

In order to solve the above-mentioned problems, a chlorine concentration measuring device of the present invention is a device for measuring the chlorine concentration of produced water produced by applying an electrolytic voltage to electrodes of an electrolytic cell. There, current value measuring means for measuring the electrolysis current value of the electrolytic cell, conductivity measuring means for measuring the conductivity of the generated water, conductivity measured by the conductivity measuring means and the current value measurement. The chlorine concentration measuring means for measuring the chlorine concentration based on the electrolytic current value measured by the means.

[0006]

The chlorine concentration is measured based on the conductivity measured by the conductivity measuring means and the electrolytic current value measured by the current value measuring means. Since the conductivity and the electrolysis current value have a linear proportional relationship and the chlorine concentration can be known from the conductivity, p
It is possible to accurately measure the chlorine concentration of strongly acidic water around H2.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an electric circuit diagram of the chlorine concentration measuring device of the present invention, and FIG. 2 is an overall configuration diagram of a strong acid water generator to which the chlorine concentration measuring device is applied.

In FIG. 2, a solenoid valve 22, a pressure reducing valve 23, and a pipe 21a for taking in tap water from a water pipe (not shown) are provided.
A constant flow valve 24 and a flow meter 25 are sequentially attached, and an output pipe 21c of a mixing water tank 26 in which mixing water (saline solution in this embodiment) is stored is connected to an output side pipe 21b of the flow meter 25. , Connected to the mixer 27. The output pipe 21c is provided with a metering pulse pump 28 for adjusting the discharge amount of the salt water stored in the mixing water tank 26 and a check valve 29 for preventing backflow into the mixing water tank 26.

The pipe 21d on the output side of the mixer 27
In addition, the pre-electrolysis conductivity meter 30 for measuring the conductivity of the mixed water flowing in the pipe, and the pre-electrolysis water thermometer 4 for measuring the water temperature of the mixed water
8 are attached and connected to the inflow port 31a of the electrolytic cell 31. The inside of the electrolytic cell 31 is partitioned into two chambers by a diaphragm 31b, and each electrolytic chamber has an electrolytic power source 32.
A pair of electrodes 31c and 31d, which serve as both a cathode and an anode by switching at, are arranged. Diaphragm 31b
Is formed of a synthetic resin thin film that allows hydrogen ions, hydroxide ions, and other metal ions to pass therethrough, making it difficult for water molecules to pass through.

In addition, in the upper part of each electrolysis chamber of the electrolysis cell 31,
An outlet 31e for taking out strongly acidic water and alkaline water generated around each electrode 31c, 31d by electrolysis,
31f are formed, and these outlets 31e, 31
Each of the pipes 21e and 21f connected to
And the second three-way valves 33, 34 are attached. Then, in one output side pipe 21g of the first three-way valve 33, a post-electrolysis conductivity meter 35 for measuring the conductivity of the generated water after electrolysis.
And a post-electrolysis water thermometer 49 that measures the water temperature of the generated water after electrolysis are connected to the third three-way valve 36, and one output side pipe 21i of the third three-way valve 36 is generated. The generated strong acid water is introduced into the produced water storage tank 37. The other output side pipe 21j of the third three-way valve 36 is a discharge pipe to the outside.

On the other hand, one output side pipe 21k of the second three-way valve 34 is also a discharge pipe to the outside, and the first three-way valve 3
The other output pipe 21h of No. 3 is connected to one output pipe 21k of the second three-way valve 34 and the other output pipe 2 of the second three-way valve 34.
1 m is connected to one output pipe 21g of the first three-way valve 33, respectively. Further, a liquid amount sensor 41 is attached to the produced water storage tank 37, and a discharge pump 38 is attached to the extraction pipe 21n, and the output side pipe of the discharge pump 38 is branched into two.
Faucets 39 and 40 are attached to the respective branch pipes 21p and 21q via solenoid valves 43 and 44, respectively.

The solenoid valve 2 thus constructed
2, flow meter 25, quantitative pulse pump 28, pre-electrolysis and post-electrolysis conductivity meters 30, 35, pre-electrolysis and post-electrolysis water thermometer 4
8, 49, electrolytic power source 32, three-way valves 33, 34, 36,
Each of the discharge pump 38, each faucet 39, 40, the liquid amount sensor 41, each electromagnetic valve 43, 44, etc., is bidirectionally or unidirectionally connected to the CPU 42 according to its function, as indicated by a broken line in the drawing. It is composed. CPU 42
Although not shown in the figure, it is provided with a ROM, a RAM, and the like that store an operation program, which controls the operation of the entire apparatus.

Next, the electrical construction of the chlorine concentration measuring apparatus of the present invention applied to the strongly acidic water generator having the above construction will be described with reference to FIG. In FIG. 1, the same components and members as those of the strongly acidic water generator shown in FIG. 2 are designated by the same reference numerals.

This chlorine concentration measuring device is basically a current value measuring section for measuring the electrolysis current value flowing between the electrodes 31c and 31d of the electrolytic cell 31 by the electrolysis conductivity meter 35 and the electrolysis voltage of the electrolysis power source 32. 65, and chlorine concentration measuring means for obtaining the chlorine concentration based on the electrolysis conductivity measured by the post-electrolysis conductivity meter 35 and the electrolysis current value measured by the current value measuring unit 65 (in the present embodiment, the CPU 42 And a display unit 50 for displaying the chlorine concentration and the like obtained by the CPU 42. In addition, the current value measuring unit 65
Is an amplifier circuit 56 that amplifies the measured electrolytic current value,
It is composed of an A / D conversion circuit 53 which converts the output into digital data and guides it to the CPU 42. Then, the post-electrolysis conductivity measured by the post-electrolysis conductivity meter 35 is converted into digital data by the A / D conversion circuit 51 and guided to the CPU 42.

However, the CPU 4 which is a chlorine concentration measuring means
In addition to this, the temperature data measured by the post-electrolysis water thermometer 49 is converted into digital data by the A / D conversion circuit 52 and introduced, and the conductivity measured by the pre-electrolysis conductivity meter 30 is also shown in FIG. The rate data is converted into digital data by the A / D conversion circuit 55 and introduced, and the water temperature gauge before electrolysis 48
The temperature data measured in step A is converted into digital data by the A / D conversion circuit 54 and introduced.

The post-electrolysis conductivity meter 35 is provided with a pair of electrodes 61, 62 (in this embodiment, the shape is a parallel plate) having a constant area with a constant distance in the pipe 21g. One electrode 61 of the pair of electrodes 61, 62 is connected to the ground and the other electrode 6
2 is connected to the midpoint a of two dividing resistors connected in series between the reference voltage Vcc and the ground. The analog voltage obtained at the midpoint a is the A / D conversion circuit 5
The data is converted into digital data by 1 and loaded into the CPU 42. Although not described, the pre-electrolysis conductivity 30 also has the same configuration.

The CPU 42 basically measures the chlorine concentration based on the conductivity measured by the post-electrolysis conductivity meter 35 and the electrolytic current value flowing between the electrodes 31c and 31d.
In addition, in order to make the measured value of the chlorine concentration more accurate, and to make more reliable the judgment of abnormality and the like based on the measured value, the temperature data measured by the post-electrolysis water thermometer 49 and Various calculation processes are performed by using the conductivity data measured by the pre-electrolysis conductivity meter 30 and the temperature data measured by the pre-electrolysis water temperature meter 48.

The operation of this chlorine concentration measuring device will be described below. The electric conductivity obtained by the electric conductivity meter 35 after electrolysis and the electrolysis current value flowing between the electrodes 31c and 31d have a linear proportional relationship as shown in FIG. Conversely, the electrical conductivity is a value indicating the resistance of water (for example, tap water) flowing inside, and the resistivity decreases as the electrical conductivity increases, so that the electrolytic current value also increases accordingly. That is,
The higher the mixing ratio of the salt water to the tap water (that is, the higher the salt concentration increases), the lower the resistivity and the higher the conductivity. That is, the electroconductivity of the generated water after electrolysis increases in proportion to the amount of electrochemical reaction (that is, current value) due to the ionization of Cl that has been bound until then. Therefore, since most of the ions of the acidic water are Cl, the chlorine concentration of the acidic water can be inferred from the value of its conductivity and indirectly measured.

The CPU 42 stores in advance a relational data of such conductivity, electrolysis current value, and chlorine concentration as a database in advance, so that the relational data stored in this database, the conductivity, and the electrolysis are stored. The chlorine concentration at that time can be obtained from each measurement data of the current value. Moreover, since the relationship between the chlorine concentration and the electric conductivity or the electrolysis current value is a linear proportional relationship, it is possible to accurately measure the chlorine concentration even in a strongly acidic range around pH 2.

On the display unit 50, it is possible to display the chlorine concentration measured in this way as it is, but for example, the degree of the sterilizing ability indicated by the chlorine concentration is strongly indicated.
It is possible to notify the user of the current sterilization ability (chlorine concentration) by dividing into three stages of medium and weak and turning on a display lamp (not shown) showing each stage.

Further, the CPU 42 stores, in the database, the measured value of the conductivity with respect to the measured value of the electrolytic current, for example, based on the relational data stored in this database and the measured data of the conductivity and the electrolytic current value. When it is an abnormal value separated by a certain width or more from the relationship data, it is determined that the electrolytic abnormality has occurred and, for example, the display unit 50
Processing such as turning on a display lamp (not shown) indicating the abnormality is performed.

The above is the basic operation of the chlorine concentration measuring apparatus of the present invention, but in addition to this, the following operation is possible. That is, the conductivity changes depending on the water temperature (for example, if the water temperature rises by 1 degree, the conductivity rises by 2%).
Therefore, the temperature of the conductivity can be corrected by the water temperature after electrolysis measured by the post-electrolysis water thermometer 49. This makes it possible to measure the chlorine concentration more accurately.

The electrolysis voltage of the electrolysis power source 32, the water temperature measured by the pre-electrolysis water thermometer 48, and the pre-electrolysis conductivity meter 3
It is empirically known how much the electrolysis current value becomes by the conductivity measured by 0.
By storing it in the database of 42, it is possible to judge whether or not the electrolytic current value is normal by comparing this empirical value with the actual measured value of the electrolytic current. That is, first, it can be determined whether or not the electrolytic current value is normal, and then it can be determined whether or not the conductivity is normal for a normal electrolytic current value. That is, the chlorine concentration can be more accurately measured by performing such a two-step stance determination process.

[0024]

EFFECT OF THE INVENTION The chlorine concentration measuring device of the present invention comprises a current value measuring means for measuring the electrolysis current value of the electrolytic cell, a conductivity measuring means for measuring the conductivity of the produced water, and the conductivity measuring means. And chlorine concentration measuring means for measuring the chlorine concentration based on the electrolysis current value measured by the electric current value measuring means, and the chlorine concentration is calculated from the electrolysis current value and the conductivity which are in a linear proportional relationship. Since it was configured to ask
Particularly, the chlorine concentration in the strongly acidic range can be easily and accurately measured.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing an electrical configuration of a chlorine concentration measuring device of the present invention.

FIG. 2 is an overall configuration diagram of a strongly acidic water generator to which the chlorine concentration measuring device of the present invention is applied.

FIG. 3 is a graph showing the relationship between electrolysis current value and conductivity.

FIG. 4 is a graph showing the relationship between pH value and current value.

[Explanation of symbols]

 31 Electrolytic Tank 31c, 31d Electrode 32 Electrolytic Power Supply 35 Post Electrolysis Conductivity Meter 42 CPU (Chlorine Concentration Measuring Means) 56 Amplification Circuit 51, 53 A / D Conversion Circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G01N 27/49

Claims (1)

[Claims] 1. An apparatus for measuring the chlorine concentration of produced water produced by applying an electrolysis voltage to an electrode of an electrolytic cell, comprising: current value measuring means for measuring an electrolytic current value of the electrolytic cell; Conductivity measuring means for measuring the conductivity of generated water, and chlorine concentration measurement for measuring chlorine concentration based on the conductivity measured by the conductivity measuring means and the electrolytic current value measured by the current value measuring means. A chlorine concentration measuring device comprising means.