JPH0610308Y2 - Ion densitometer reference electrode - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION {Industrial Application Field} The present invention relates to a reference electrode of an ion densitometer used for measuring the ion concentration of industrial wastewater and other solutions.

{Prior Art} Ion densitometers generally measure the concentration of target ions by combining an ion electrode and a reference electrode and measuring the difference in electromotive force generated between these electrodes. It is a thing.

The reference electrode has a support tube filled with an internal liquid such as a concentrated potassium chloride solution. Then, in order to function stably for a long period of time, a small amount of the internal liquid is made to flow out toward the test liquid from a liquid junction provided in a part of the support tube. Requires.

As an ion densitometer, for example, the one shown in FIG. 5 is known.

In FIG. 5, reference numeral 41 denotes a composite electrode, which is an inner electrode of the ion electrode (not shown) in the inner tube of the support tube 42 having a double tube structure.
And an inner electrode (not shown) of the reference electrode is inserted into the outer tube. An internal liquid supply hole 43 is provided in the upper part of the outer tube of the support tube 42, and a liquid junction part such as porous ceramic is provided in the lower part.
44 are provided respectively.

45 is a holder made of pipe, packing attached to its end
The composite electrode 41 is attached to the holder 45 by penetrating through 46 in a watertight manner. Reference numeral 47 is a supply hole for the internal liquid provided in the upper portion of the holder 45, and 48 is a protective pipe for the composite electrode 41.

Then, the liquid level of the internal liquid 49 in the holder 45 is made higher than the liquid level of the test liquid 50, and the reduced amount of the internal liquid in the support tube 42 flowing out from the liquid junction 44 is supplied to the replenishment hole 43. I am trying to replenish it from.

The ion concentration meter shown in FIG. 6 is also known.

In FIG. 6, 51 is an ion electrode, which is constructed by inserting an inner pole (not shown) into the lower end of the ion electrode support tube 52.

Reference numeral 53 is a reference electrode, which is configured by inserting an inner electrode (not shown) into the lower end of the reference electrode support tube 54, and is internally provided at the upper end of a reservoir 55 provided at the upper part of the reference electrode support tube 54. A liquid inlet 56 is formed. Reference numeral 57 is a liquid junction provided at the lower end of the reference electrode support tube 54, from which a small amount of the internal liquid 58 flows out.

The ion electrode support tube 52 is placed in the comparison electrode support tube 54.
And the lower ends thereof are integrated with each other to form a composite electrode a.

Reference numeral 59 is a pipe-shaped holder, into which the composite electrode a is inserted, and the lower end of which is projected outside the holder 59.
Reference numeral 60 denotes a protective pipe provided on the holder 59, and a hole 61 is provided to facilitate replacement of the test liquid.

Reference numeral 62 denotes an air supply hole provided at the upper end of the holder 59, to which the pipe connector 63 is connected. 64 is a pressure gauge.

This ion densitometer supplies pressurized air into the holder 59 from the pipe connector 63, causes the pressure to act on the internal liquid 58 in the reservoir 55, and causes the internal liquid to flow out from the liquid junction 57. It is a thing.

{Problems to be Solved by the Invention} The conventional ion concentration meter shown in FIG. 5 has a simple structure, but when the pressure on the test liquid 50 side is high, the liquid junction 44 to the test liquid 50 is used. However, there is a problem that it flows backwards and becomes unusable.

The ion concentration meter shown in FIG. 6 solves the problem of the ion concentration meter shown in FIG.

That is, the reference electrode is generated by the pressure of the air supplied into the holder 59.
The internal liquid 58 of 53 is pressurized to prevent the test liquid from flowing backward from the liquid junction 57 even when the pressure on the test liquid side is high, so that the internal liquid can reliably flow out from the liquid junction 57. I have to.

However, since there is a need for equipment for pressurizing the internal liquid of the reference electrode 53, there is a problem that the cost becomes high and it cannot be used in a place without such equipment.

The present invention solves the above-mentioned problems, and it is possible to let the internal liquid flow out from the liquid junction regardless of the pressure on the side of the liquid to be detected. The purpose of the invention is to obtain a reference electrode that does not have a back flow of the.

{Means for Solving the Problem} The present invention provides a reference electrode of an ion densitometer, in which a liquid junction is formed in a support tube containing an inner electrode and an internal liquid, and the reference electrode is provided in the support tube. A semi-permeable membrane is attached as a partition member to the replenishing liquid replenishing part provided in the liquid passage hole or the support pipe, and the replenishing liquid such as water is supplied to the support pipe through the semi-permeable membrane. It is characterized in that the same kind of crystals as the internal liquid was stored in the tube.

{Action} This reference electrode supplies a replenishing liquid such as water to the internal liquid in the support tube through the semipermeable membrane. And
Since the internal solution contains a concentrated salt such as a potassium chloride solution as a component, there is an internal solution that is a solution containing a large amount of ions in the support tube through the semipermeable membrane, and on the opposite side, there is an ion. There is a replenisher such as water, which is a solution containing less water.

Therefore, due to the action of the semipermeable membrane, a replenishing liquid such as water permeates it to be replenished to the support tube, and a large osmotic pressure is generated in the support tube. This osmotic pressure acts on the internal liquid in the support tube, and causes the internal liquid to flow out of the support tube from the liquid junction.

In the reference electrode, since the reference electrode support tube contains crystals of the same type as the internal liquid (for example, potassium chloride crystals when the internal solution is a potassium chloride solution), the replenisher solution is stored in the reference electrode support tube. Even if it flows in, the decrease of the internal liquid concentration due to the inflow of the replenishing liquid is effectively prevented.

Example An example of the comparative electrode of the present invention will be described with reference to a composite electrode shown in FIG. 1 in which the comparative electrode and the ion electrode are integrally formed.

In FIG. 1, reference numeral 1 is an ion electrode, which is constructed by arranging an inner pole 3 at the lower end of an ion electrode support tube 2.

Reference numeral 4 is a reference electrode, which is constructed by arranging an inner electrode 6 at the lower end of the reference electrode support tube 5, and a large-diameter internal liquid storage section 7 is provided above the reference electrode support tube 5. An inlet 8 for the internal liquid is formed at the upper end of the reservoir 7.
9 is a plug of the injection port 8, 10 is a liquid junction part provided at the lower end of the reference electrode support tube 5 and made of a porous ceramic or the like.
From this, the internal liquid 11 is made to flow out in small amounts. 12 is the storage section 7
The liquid passage hole formed in the above, which is closed by the semipermeable membrane 13.

The semipermeable membrane 13 can be fixed to the reservoir 7 by any means such as adhesion with an adhesive or heat welding depending on the materials of the two.

Then, the ion electrode support tube 2 is provided in the comparison electrode support tube 5.
Are inserted, and their lower ends are integrated with each other to form a composite electrode A.

Reference numeral 14 is a pipe-shaped holder, into which the composite electrode A is inserted, and the lower end portion of which is projected in a watertight manner outside the holder 14. Reference numeral 15 denotes a protective pipe provided on the holder 14 for protecting the portion of the composite electrode A protruding from the holder 14, and a hole 16
Is provided to facilitate replacement of the test liquid.

Reference numeral 17 designates a replenishing liquid storage portion formed on the holder 14 at the outer peripheral portion of the storage portion 7, and reference numeral 18 designates a supply port provided on the upper portion of the holding tool 14, and a pipe 19 connected thereto serves as a replenishing liquid in the storage portion 17. Supply water.

This ion densitometer is used with its lower end inserted in the test liquid. The injection of the internal liquid into the comparison electrode support tube 5 of the comparison electrode 4 is performed from the injection port 8.
Is sealed with a stopper 9, but crystals such as potassium chloride are also added at this time. Then, water is injected into the containing portion 17 through the pipe 19.

Therefore, the internal liquid 11 does not come out of the reference electrode support tube 5 due to the semipermeable membrane 13, but the water in the containing portion 17 permeates from the semipermeable membrane 13 to the reservoir portion 7 side. It is possible to compensate for the decrease in the internal liquid that has flowed out to the test liquid side.

Moreover, since water permeates from the semipermeable membrane 13 to the reservoir 7 side, a large osmotic pressure is generated in the reference electrode support tube 5 and acts on the internal liquid 11, so that the internal liquid 11 side and the test liquid When there is no difference in the pressure on the side of the internal liquid 11, it is possible to let the internal liquid 11 flow out from the liquid junction 10 to the side of the test liquid, and even if the pressure on the side of the test liquid is higher, It is possible to reliably flow out from the junction 10 to the test liquid side, and it is possible to prevent the test liquid from flowing back from the liquid junction 10 into the reference electrode support tube 5.

Further, in the above-mentioned reference electrode, since crystals of potassium chloride of the same kind as the internal liquid 11 are contained in the supporting tube 5, even if the replenishing liquid flows into the supporting tube 5, the concentration of the internal liquid 11 is increased. Does not decrease.

FIG. 2 shows another embodiment of the reference electrode.

The comparative electrode 24 of this embodiment is configured such that the inner electrode 26 is arranged at the lower end of the comparative electrode support tube 25, and the internal liquid inlet 28 is provided at the upper part of the comparative electrode support tube 25. 29 is the inlet
It is a plug that closes 28. Reference numeral 30 is a liquid junction provided at the lower end of the comparison electrode support tube 25, 31 is an internal liquid, and 32 is a liquid passage hole provided in the comparison electrode support tube 25, which is closed by a semipermeable membrane 33.

Reference numeral 34 denotes an outer tube integrally formed with the reference electrode support tube 25 and formed in a double-tube shape outside the portion overlapping the semipermeable membrane 33, and a replenisher storage portion 35 is formed between this and the reference electrode support tube 25. A pipe 37 such as a tube is connected to a supply port 36 provided in the outer pipe 34. Reference numeral 38 is a seal member such as an O-ring interposed between the reference electrode support tube 25 and the outer tube 34.

The reference electrode 24 is also filled with the internal liquid from the inlet 28,
The inlet 28 is closed at 29. Then, from the pipe 37 to the housing portion 35
Inject water as a replenisher into the.

Therefore, the water in the containing portion 35 permeates the semipermeable membrane 33 and flows toward the reference electrode supporting tube 25 side to replenish the internal liquid flowing out from the liquid junction portion 30. Further, as a result, a large osmotic pressure generated in the reference electrode support tube 25 acts on the internal liquid 31, so that the internal liquid 31 can be reliably discharged from the liquid junction 30 even when the pressure on the test liquid side is high. .

FIG. 3 also shows another embodiment of the reference electrode.

The reference electrode 24 has an inner electrode at the lower end of the reference electrode support tube 25.
26 is arranged, and an internal liquid inlet 28 and a replenishing liquid replenishing port 36 are provided above the reference electrode supporting tube 25. 29 is a plug of the inlet 28, and 37 is a pipe such as a tube as a replenishing part connected to the replenishing port 36, to which a pipe-shaped semipermeable membrane mounting member 39 is connected. Reference numeral 33 is a semi-permeable membrane attached inside the semi-permeable membrane attachment member 39 so as to block it. Further, 40 is a pipe such as a tube connected to the semipermeable membrane mounting member 39.

In the comparative electrode 24 of this embodiment, water is injected into the pipe 40 and permeates the comparative electrode support pipe 25 side through the semipermeable membrane 33. Since the semipermeable membrane 33 is attached to the semipermeable membrane attaching member 39, the semipermeable membrane 33 can be easily attached, and the semipermeable membrane 33 and the semipermeable membrane attaching member 39 can be replaced arbitrarily and easily. It is possible to

The internal liquid can be injected from the replenishment port 36 by removing the pipe 37 without providing the injection port 28.

FIG. 4 also shows another embodiment of the reference electrode.

This reference electrode 24 also has an inner electrode at the lower end of the reference electrode support tube 25.
26 is provided, and an inlet 28 for the internal liquid and a water replenishing port 36 are provided above the reference electrode support tube 25. 29 is a plug of the inlet 28.

Reference numeral 39 denotes a pipe-shaped semipermeable membrane mounting member as a replenishment portion which is detachably attached to the supply port 36. The semipermeable membrane 33 is fitted to the inner end of the pipe-shaped semipermeable membrane 33 and the pipe-shaped pressing member 41 is semi-removed. The semi-permeable membrane 33 is fixed by being screwed into the permeable membrane mounting member 39. 40
Is a pipe such as a tube connected to the semipermeable membrane mounting member 39.

Also in this embodiment, water as a replenishing liquid is injected into the pipe 40 and permeates into the reference electrode supporting pipe 25 side through the semipermeable membrane 33. Since the semipermeable membrane 33 is attached to the semipermeable membrane attaching member 39, the semipermeable membrane 33 can be easily attached, and if the pressing member 40 is separated, only the semipermeable membrane 33 can be replaced. .

Needless to say, in the comparative electrodes shown in FIGS. 2 to 4, crystals of the same kind as the internal liquid 11 are put in the comparative electrode support tube 25.

{Effect of the device} As described above, the reference electrode of the present invention supplies the replenishing liquid such as water to the supporting tube in which the internal liquid is injected through the semipermeable membrane, so that the replenishing liquid is supported. By penetrating the semipermeable membrane into the tube side, a large osmotic pressure is generated in the supporting tube side, and the pressure acts on the internal liquid.

Therefore, when there is no difference in pressure between the internal liquid side and the test liquid side, the internal liquid can easily flow out from the liquid junction, and even when the test liquid side pressure is high, It is possible to reliably cause the internal liquid to flow out from the liquid junction by osmotic pressure, and prevent the test liquid from flowing back from the liquid junction.

Then, the osmotic pressure of the support tube can be changed by adjusting the area of the semipermeable membrane or the salt concentration of the replenishing liquid to be replenished, so that the amount of the internal liquid flowing out from the liquid junction can also be controlled.

Further, since the osmotic pressure of the semipermeable membrane is used, even when the pressure on the test liquid side is high, it is possible to reduce the cost because no pressurizing equipment is required unlike the conventional reference electrode. At the same time, maintenance is easy.

Further, in the reference electrode of the present invention, since the crystal of the same kind as the internal liquid is contained in the support tube, as described above, even if the replenishment solution flows into the support tube through the semipermeable membrane, the replenishment solution flows in. Therefore, the concentration of the internal liquid does not decrease, and maintenance is easy also in this respect.

[Brief description of drawings]

1 to 4 are sectional views of different embodiments of the present invention, and FIGS. 5 and 6 are sectional views of different conventional examples. 4: Reference electrode, 5: Reference electrode support tube, 6: Inner electrode, 10: Liquid junction, 12: Liquid passage hole, 13: Semipermeable membrane, 24: Reference electrode, 25: Reference electrode support tube, 26: Inner Pole, 32: liquid passage hole, 33: semipermeable membrane.

Claims (1)

[Scope of utility model registration request] 1. A reference electrode of an ion densitometer in which a liquid junction is formed in a support tube in which an inner electrode and an internal liquid are stored, the reference electrode being provided in a liquid passage hole provided in the support tube or in the support tube. A semi-permeable membrane is attached as a partition member to the replenishing part of the replenishing liquid thus prepared, and the replenishing liquid such as water is supplied to the supporting pipe through the semi-permeable membrane, and a crystal of the same type as the internal liquid is supplied in the supporting pipe. A reference electrode for an ion densitometer, characterized in that