JPS5928356Y2 - Diaphragm electrode - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a diaphragm type electrode used for water quality measurement, liquid concentration measurement, dissolved gas concentration measurement in liquid, etc.

For example, in this type of diaphragm-type ammonia gas electrode, as shown in FIG. are arranged so that the detection end is close to the inner surface of the diaphragm 1, a reference electrode 4 is also arranged, and the internal liquid 2 is injected into the electrode outer cylinder 5 so that these electrodes are immersed.

By immersing this electrode outer cylinder 5 in the test liquid,
The ammonia gas dissolved in the test liquid permeates through the diaphragm 1 and diffuses into the internal liquid 2, thereby reducing the p of the internal liquid 2.
The amount of ammonia gas dissolved in the test liquid is measured by detecting the change in the H value using the detection electrode 3 and the comparison electrode 4.

If this type of electrode is immersed in the test liquid for a long period of time, the ammonia gas that has passed through the diaphragm 1 and entered the electrode outer cylinder 5 will be transferred from the vicinity of the diaphragm 1 to the internal liquid over time. 2, the entire internal liquid becomes strongly alkaline and does not follow changes in the ammonia gas concentration in the test liquid that is in contact with the outer surface of the diaphragm 1.

Therefore, when the concentration of ammonia gas dissolved in the internal liquid no longer follows the concentration of ammonia gas dissolved in the test liquid, it is necessary to replace the internal liquid with a new liquid.

The period from the start of use to the time when the internal solution is replaced with a new one varies depending on the amount of internal solution, the size of the electrode, the concentration of the substance to be measured in the test solution, and the conditions of use. Since the determination must be made by conducting an extraction test of the internal liquid every period, care must be taken in maintenance, and if replacement is delayed, measurement errors may occur, or accidents such as failure to measure may occur.

The present invention aims to provide a diaphragm type electrode free from such problems.

In order to achieve this purpose, the present invention provides another second detection electrode in addition to the conventional detection electrode, with the detection end positioned at a position where the average concentration of the internal liquid can be detected. The reference electrode is connected to a device that indicates when the concentration of a specific component in the internal solution exceeds a predetermined value.

FIG. 2 shows an embodiment of the diaphragm-type electrode according to the present invention, in which the same diaphragm 1, internal liquid 2, and first detection electrode 3 as in FIG. 1 are shown.
In the case of an ammonia gas electrode, a microporous Teflon (registered trademark) thin film is used as the diaphragm 1, an ammonium chloride aqueous solution is used as the internal solution 2, and a glass electrode for pH measurement is used as the first detection electrode. It is used.

Another glass electrode, which is the same as the first detection electrode, is arranged as a second detection electrode 6 with its sensitive glass membrane positioned approximately in the upper and lower center of the internal liquid 2.

This electrode is connected to the first detection electrode 3 as shown in FIG.
and comparison electrode 4 are connected to an indicator, a display, or a recorder 8 via an amplifier 7 in the same manner as in the past, by a conductor a connected to the first detection electrode 3 and a conductor wire connected to the comparison electrode 4. , the second detection electrode 6 and the comparison electrode 4 are connected to the potential difference comparison circuit 9 through a conductor C connected to the second detection electrode and a conductor d connected to the comparison electrode 4, and the potential difference comparison circuit 9 and this an amplifier 10 connected to a relay 11 . operated by the amplifier 10 . It is connected to a device that indicates when the concentration of a specific component in the internal fluid exceeds a predetermined value, such as an internal fluid exchange display device or alarm device 12 operated by a relay 11.

When this electrode is inserted into the test liquid from the diaphragm 1 side, the ammonia gas dissolved in the test liquid passes through the diaphragm 1 and enters the internal liquid 2, increasing the pH near the first detection electrode. change.

As in the conventional method, a potential difference proportional to this pH is generated between the first detection electrode 3 and the comparison electrode 4, and this is displayed as the ammonia gas concentration on the display or recorder 8.

If you continue to use it in this way for a long time, the internal fluid
The overall dissolved ammonia gas concentration becomes large.

Even between the reference electrode 4 and the second detection electrode 6, the pH of the internal solution 2
This output is compared with the potential at a predetermined location in the comparator circuit 9, and the alarm device 12 etc. automatically detects that it is time to replace the internal fluid 2 based on the voltage difference. It is designed to notify the operator.

FIG. 3 shows another embodiment of the present invention, in which metal electrodes 3' and 6 are used instead of glass electrodes as the first detection electrode 3 and the second detection electrode 6.
These are sealed in one support tube, with 3' at its lower end near the diaphragm 1, and 6' protruding from the middle to be exposed to the internal liquid 2.

The structure and effects of other parts are the same as those shown in FIGS. 2 and 4.

In the above embodiments, the reference electrode 4 is used both for detecting the component concentration of the test liquid and for detecting the component concentration of the internal solution. Separate comparison electrodes may be provided for concentration detection.

According to the present invention, the diaphragm type electrode can be replaced without worrying about when to replace the internal fluid, and problems caused by delays in replacing the internal fluid can be eliminated.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing the structure of a conventional diaphragm type ammonia gas electrode, Fig. 2 is a longitudinal sectional view showing the structure of an embodiment of the present invention applied to a diaphragm type ammonia gas electrode, and Fig. 3 is a longitudinal sectional view showing the structure of a conventional diaphragm type ammonia gas electrode. The figure is a longitudinal sectional view showing another embodiment of the electrode of the present invention, and FIG. 4 is a block diagram showing an example of measurement and connection of the electrode of the present invention to a display device. 1...Diaphragm, 2...Internal fluid, 3...
...First detection electrode, 4...Comparison electrode, 5...
... Electrode outer cylinder, 6 ... Second detection electrode, 7.
...Amplifier, 8...Recorder, 9...
...Potential comparison circuit, 10...Amplifier, 11...
...Relay, 12...Alarm device, a, b,
c, d... Conductor wire.

Claims (1)

[Scope of utility model registration request] A first detection electrode is placed in the internal liquid in the electrode outer cylinder and has a detection end close to the inner surface of a diaphragm fixed to the electrode outer cylinder, and a second detection electrode is located at a position where the average concentration of the internal liquid can be detected. A diaphragm type electrode in which a detection electrode and a comparison electrode are arranged, and the second detection electrode and the comparison electrode are connected to a device that indicates when the concentration of a specific component in the internal solution exceeds a predetermined value.