JP2000055866A - COMBINED ELECTRODE FOR pH MEASUREMENT AND FOR OXIDATION-REDUCTION POTENTIAL MEASUREMENT - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a combined electrode by which a disturbing flow is prevented and by which a liquid, to be detected, in a trace amount can be measured in a stable liquid flow by a method wherein a pH measuring tube, an oxidation-reduction potential measuring tube and a temperature compensating tube are installed at the upper part of a cylindrical measuring-device body in such a way that their tip parts are faced with the flow passage of the liquid to be detected. SOLUTION: A pH measuring tube 3 whose surface is covered with an insulating membrane and in which a glass electrode 2 is built and an ORP measuring tube 5 which is covered with an insulating membrane and in which a platinum electrode 4 for ORP measurement is built are arranged at the upper part at the inside of the cylinder of a measuring-device body 1. Its sensing parts 3' and the like are faced with the measuring part 6 of a liquid, to be detected, in the measuring-device body 1. The measuring part 6 forms the flow passage of the liquid to be detected, and an inflow port 7 and a discharge port 8 for the liquid to be detected are provided. A temperature compensating tube 10 which corresponds to the ORP measuring tube 5 and in which a temperature compensating resistance 9 is built is arranged at the inside of the cylinder of the measuring-device body 1. By using a combined electrode which is constituted in this manner, the liquid to be detected can be measured while it is being made to flow into continuously in such a way that the tip of a measuring device is not immersed in the liquid, to be detected, every time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite electrode for measuring pH and oxidation-reduction potential comprising a glass electrode for measuring pH, a platinum electrode for measuring oxidation-reduction potential and a reference electrode.

[0002]

2. Description of the Related Art Conventionally, the oxidation-reduction potential (hereinafter referred to as ORP) is affected by the pH of a solution. Therefore, ORP
It was necessary to measure the pH value at the same time. Therefore, there is a combination of an ORP measurement transducer, a platinum electrode and a reference electrode as an ORP measurement instrument, and a combination of an ORP measurement transducer, a glass electrode, and a comparison electrode as a pH measurement instrument. Was. A large composite electrode or the like in which a comparison electrode is individually arranged in addition to the oxidation-reduction potential measurement electrode is used.

For example, in a pH measuring device as shown in FIG. 4 used for measuring a small amount of a test liquid or a test liquid having a small ionic strength, a flow path for the test liquid is provided at the bottom of a container body. The ends of the pH measurement electrode and the electrode of the temperature compensating member are arranged facing this flow path, and a depression is provided at the bottom of the flow path of the container body in the central part, and the front end of the comparison electrode is fitted. The test liquid is passed through the flow path from the right to the left in FIG. 4 to continuously measure the pH value.

[0004]

As shown in FIG. 4, the conventional measuring device has a pH measuring electrode, a reference electrode, a temperature compensating electrode and the like arranged in one box and arranged in a box. It was large. Furthermore, the tip of the electrode for pH measurement faces the central part of the flow path of the test liquid, and the reference electrode is provided with a liquid junction in a recess provided at the bottom of the flow path to stabilize the potential of the reference electrode. However, a turbulent flow was apt to occur in the measuring section around these measuring electrodes, and when passing a small amount of the test liquid, stable data could not be grasped, so that a large amount of the test liquid was not mixed. In addition, for ORP measurement, as described above,
Since the value also had to be measured, a measuring instrument similar to that of FIG. 4 was separately required. In addition, since each electrode tip is immersed in a test solution for measurement, it is necessary to take out and insert the electrodes or calibrate the standard solution. An object of the present invention is to provide a composite electrode for pH measurement and oxidation-reduction potential measurement in which a pH measurement electrode and an ORP measurement electrode are arranged in one cylinder and a comparison electrode is arranged. Another object of the present invention is to provide a small-sized composite electrode capable of preventing turbulent flow in the measurement section of the pH measurement electrode and the ORP measurement electrode and capable of measuring a small amount of a test liquid with a stable liquid flow. is there.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a pH measuring tube having a built-in pH measuring glass electrode to which a lead wire is connected at the center upper portion of a cylindrical measuring device main body. And an oxidation-reduction potential measurement tube containing a platinum electrode for ORP measurement, and a temperature compensation tube containing a temperature compensation resistor are arranged. A reference electrode tube having a built-in internal electrode is arranged adjacent to each tube, and the tip of the reference electrode tube is provided below the measuring instrument main body in proximity to the liquid junction immersed in the internal liquid. The measurement part of the test liquid flow path portion is disposed in the upper half of the main body, and the flow of the test liquid flows to the side surface of the main body of the measuring instrument such that the test liquid flows into the lower bottom part of the measurement part. An inlet is provided, and a discharge port is provided slightly above the inflow port and above the measurement section. Arranged to be, these said pH
The above object can be achieved by a configuration in which a lid for sealing the upper end of a measuring instrument main body in which a lead wire of a glass electrode for measurement and a lead wire of the platinum electrode for ORP measurement is provided.

Further, the pH measuring cylinder, the oxidation-reduction potential measuring cylinder, the temperature compensating cylinder, and the comparison electrode cylinder, each of which is covered with an insulating film in a cylindrical main body, are arranged in a circle adjacent to each other in a single cylinder. The above object can be achieved by a configuration arranged in an arc shape. Further, the internal electrode for the comparison electrode in the comparison electrode tube is immersed in a potassium chloride solution tube as an internal solution, and a porous ceramic is disposed at a tip portion of the potassium chloride solution tube to cover the porous ceramic. The above object can be achieved by a configuration immersed in a test solution.

[0007] The composite electrode of the present invention has p
Since the H measurement tube and the ORP measurement tube are arranged in an arc shape and the flow path measurement unit into which the test liquid flows is arranged at the upper part of the main body, the flow is rectified and passed through the measurement unit without generating turbulence, Stable measurement can be performed, and furthermore, consumption of the internal liquid can be prevented by natural diffusion into the internal liquid with a small flow of the test liquid. In addition, since the temperature compensating member is also disposed in the cylinder of the main body and is close to the individual measurement portions, the correction accompanying the temperature compensation is accurate.

[0008]

DETAILED DESCRIPTION OF THE INVENTION pH Measurement and ORP of the Invention
Since the measurement composite electrode has the flow path measurement unit arranged at the upper part in one cylinder and the sensitive part of the comparison electrode arranged at the lower part, the whole can be made compact. In addition, since the internal electrode portion of the reference electrode is disposed below, a stable standard value can be obtained without causing turbulence in the internal liquid due to the natural diffusion of the test liquid. In addition, a conventional pH meter and OR
Although there was an individual P-measuring device, since the pH value affects the ORP measurement, the ORP value and the pH value of the test solution can be measured simultaneously by the composite electrode of the present invention. Can reliably grasp both measured values.

The composite electrode of the present invention will be described with reference to the drawings. 1 (a) and 1 (b) are a plan view and a cross-sectional view of one embodiment of a composite electrode according to the present invention. FIG. 2 (a),
(B) is the top view and sectional drawing which rotated the composite electrode of FIG. 1 90 degrees. FIG. 3 is an explanatory diagram showing a measurement state of the composite electrode of the present invention. FIG. 4A is a perspective view of a conventional composite electrode, and FIG. 4B is an enlarged sectional view of a main part.

As shown in FIG. 1, the upper surface of the inside of the cylinder of the measuring device main body 1 is covered with an insulating film, and is covered with an insulating film in the same manner as the pH measuring tube 3 containing the glass electrode 2.
An ORP measurement tube 5 containing a platinum electrode 4 for RP measurement is arranged, and these sensitive parts 3 ′ or 5 ′ are connected to the measuring part 6 of the test liquid of the measuring instrument body 1 (the flow path of the test liquid). Part). The measuring device main body 1 is a plastic cylinder. The measuring section 6 forms a flow path of the test liquid, and the measuring section 6 has an inlet 7 for injecting the test liquid and an outlet 8 for discharging the test liquid.
Are provided. A temperature compensating cylinder 10 having a built-in temperature compensating resistor 9 is arranged in the cylinder of the measuring device main body 1 in correspondence with the ORP measuring cylinder 5 of the measuring section 6.

On the other hand, the pH measuring cylinder 3 has a glass electrode 2 built therein. The sensitive part 3 ′ faces the center of the flow path of the measuring part 6. A lead wire 18 is connected to the upper end of the pH measurement tube 3.
Is connected. Also, the platinum electrode 4 of the ORP measuring cylinder 5
The sensing part 5 ′ faces the flow path of the measuring part 6, and a lead wire 19 is connected to the upper end of the ORP measuring cylinder 5. The sensitive portion 9 'of the temperature compensating resistor 9 at the tip of the temperature compensating cylinder 10 is arranged near the inflow port 7, and a lead wire 20 is connected to the upper end thereof, and these leads 17, 18, 19 and 20 are connected.
Is penetrated through the upper end cover 21 of the measuring instrument main body 1, and the upper end lid 21 is fixed to the measuring instrument main body 1 by a cap 22 formed on a cap nut. Reference numeral 23 denotes a seal for preventing liquid leakage from the external liquid cylinder 16.

The reference electrode tube 11 penetrates the measuring section 6 from the upper part of the measuring instrument body 1 downward, and the comparison inner electrode 13 at the tip thereof is immersed in the lower inner liquid tube 12 filled with the inner liquid. I have. A potassium chloride solution is used as the internal liquid. The lower end of the inner liquid cylinder 12 is sealed by a cap 15 and is immersed in the outer liquid cylinder 16. A liquid junction 14 made of a porous material is fitted into the center of the cap 15. As a result, the test liquid in the external liquid cylinder 16 and the internal liquid in the internal liquid cylinder 12 communicate with each other. Comparison inner pole 1
The lead wire 17 connected to 3 is protected by a protective cylinder. The upper end of the reference electrode tube 11 is opened above the internal liquid level to replenish the internal liquid. The outer liquid cylinder 16 and the inner liquid cylinder 1 of the measuring device main body 1 used for the composite electrode of the present invention.
2 is formed of a transparent synthetic resin cylinder. For example, it is formed of a transparent cylinder made of vinyl chloride resin, acrylic resin, or the like, so that the amount of liquid inside can be observed.

A method for operating the composite electrode according to the present invention will be described. As shown in FIG. 3, a small amount of a sample liquid of a test liquid flows from an inlet 7 of a measuring instrument body 1 having a built-in composite electrode according to the present invention, flows through a measuring section 6, and a glass electrode 2, a platinum electrode 4 Then, the test liquid is discharged from the discharge port 8 through the sensitive portions 3 ', 5', 9 'of the temperature compensation resistor 9. On the other hand, a part of the test liquid flows into the external liquid cylinder 16 and mixes with the internal liquid. The pH value of this sample solution is measured by the glass electrode 2, this data is converted into digital data, digitally displayed on the pH meter 24, and written on the recorder 25 by a recording pen.
On the other hand, the oxidation-reduction potential is measured by the platinum electrode 4, and the oxidation-reduction potential is digitally displayed on the ORP meter 26, and the change over time is recorded on the recorder 25.

With respect to the composite electrode for measuring pH and measuring oxidation-reduction potential of the present invention, the inner liquid cylinder 12 and the outer liquid cylinder 1
6 is made of a transparent resin, so that the amount of potassium chloride solution and the amount of crystal of potassium chloride can be visually recognized during measurement. Therefore, replenishment of the internal solution can be ensured.

The composite electrode for pH measurement and oxidation-reduction potential measurement according to the present invention is capable of continuously placing a test liquid sample in a measuring instrument without measuring the tip of the measuring instrument while immersing the tip in the sample solution. Individual measurement data can be detected while flowing. Moreover, the pH value and the oxidation-reduction potential can be simultaneously measured by one measuring instrument, which is extremely convenient. Further, the composite electrode of the present invention can measure the test liquid on the upper side of the measuring instrument main body, and can not accurately measure the change over time of the new liquid because the measurement is not performed on the lower liquid pool portion. The test liquid can be managed. Further, since the temperature compensating cylinder is provided in the vicinity of the measuring unit in one cylinder, it is possible to correct the temperature by an accurate temperature change. In addition, a small amount of test liquid sample in the electrolytic ionic liquid is sufficient p
Since the H measurement and the oxidation-reduction potential measurement can be performed, the drainage amount of the potassium chloride solution or the like can be reduced without increasing the drainage amount of the electrolytic ionic liquid as in the related art.

[Brief description of the drawings]

FIG. 1A is a plan view of one embodiment of a composite electrode according to the present invention. (B) is the same sectional view.

FIG. 2A is a plan view in which the composite electrode of FIG. 1 is rotated by 90 degrees. (B) is the same sectional view.

FIG. 3 is an explanatory diagram showing a measurement situation of the composite electrode of the present invention.

FIG. 4A is a perspective view of a conventional composite electrode.
(B) is an enlarged sectional view of a main part of a conventional composite electrode.

[Explanation of Signs] 1 ... Measuring instrument body 2 ... Glass electrode 3 ... pH measuring tube 4 ... Platinum electrode 5 ... ORP measuring tube 6 ... Measurement unit 7 ... Inlet 8 ... Outlet 9 ... Temperature compensation resistor 10 ... Temperature compensating tube DESCRIPTION OF SYMBOLS 11 ... Reference electrode cylinder 12 ... Inner liquid cylinder 13 ... Comparative inner electrode 14 ... Liquid junction 15 ... Cap 16 ... External liquid cylinder 17,18,19,20 ... Lead wire

Claims (3)

[Claims] 1. A pH measuring glass electrode to which a lead wire is connected is built in a central upper portion of a cylindrical measuring instrument main body.
An H-measurement cylinder and an oxidation-reduction potential measurement cylinder with a built-in platinum electrode for measuring the oxidation-reduction potential are arranged, and a temperature compensation cylinder with a built-in temperature compensation resistor is arranged. A liquid junction in which a comparative electrode tube having a built-in internal electrode is arranged adjacent to each of the tubes, and the sensitive tip of the comparative electrode tube is immersed in the internal liquid below the measuring instrument body. The measurement part of the test liquid flow path part is arranged in the upper half part of the measuring instrument main body, and the measurement is performed so that the test liquid flows into the lower bottom part of the measurement part. An inlet for the test solution is provided on the side of the container body, and an outlet is provided above the measuring unit slightly above the inlet, and lead wires for the glass electrode for pH measurement and the platinum electrode for oxidation-reduction potential measurement. A lid for sealing the upper end of the measuring instrument body where the pH measurement and redox potential measuring composite electrode. 2. The method according to claim 1, wherein the pH measuring cylinder, the oxidation-reduction potential measuring cylinder, the temperature compensating cylinder, and the reference electrode cylinder, each of which is covered with an insulating film, are arranged in an arc shape adjacent to one cylinder. The composite electrode for pH measurement and oxidation-reduction potential measurement according to claim 1. 3. An internal electrode for a reference electrode in the comparative electrode tube is immersed in a potassium chloride solution tube as an internal liquid, and a porous ceramic is disposed at a tip portion of the potassium chloride solution tube. The composite electrode according to claim 1, wherein the ceramic is immersed in a test solution.