JP3441866B2 - Diaphragm type electrode - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a detection electrode and a counter electrode inside a support tube, and an internal liquid inside an electrode body formed by closing the tip opening of the support tube with a gas permeable diaphragm. The present invention relates to a diaphragm type electrode such as a sealed diaphragm type dissolved oxygen electrode, and more particularly to a diaphragm type electrode having a diaphragm breakage detecting means for detecting breakage of a gas permeable diaphragm.

[0002]

2. Description of the Related Art In a water treatment facility such as a sewage treatment facility using an aerobic biological treatment device, the concentration of dissolved oxygen contained in the water to be treated by the aerobic biological treatment device is monitored and the value of the dissolved oxygen concentration is monitored. The aeration amount of air and oxygen gas to the water to be treated is adjusted based on the above. In this case, as a measuring device for the dissolved oxygen concentration, a measuring device using a diaphragm type dissolved oxygen electrode is mainly used. As shown in FIG. 5 , this measuring apparatus has a detection electrode 6 and a counter electrode 8 connected to each other by a detection wiring 4 inside an electrically insulating support tube 2 and has a tip opening portion of the support tube 2 gas-tight. It has an electrode body 12 which is closed by a permeable diaphragm 10. A DC power supply 14 for voltage application and an ammeter 16 are connected to the detection wiring 4, and an internal liquid 18 is sealed inside the electrode body 12. Also,
The detection electrode 6 is arranged so as to face the gas permeable diaphragm 10 in a state of being close thereto, and although not shown, the side surface and the upper surface of the detection electrode 6 are surrounded by electrically insulating blocks. In this measuring device, when the dissolved oxygen contained in the sample liquid 20 reaches the detection electrode 6 after passing through the diaphragm 10, the ammeter 16 detects the current flowing between the detection electrode 6 and the counter electrode 8. The dissolved oxygen concentration in the sample liquid 20 is determined from the amount.

[0003]

As described above, the concentration of dissolved oxygen contained in the water to be treated of the aerobic biological treatment apparatus is monitored, and the amount of aeration to the water to be treated is determined based on the value of the concentration of dissolved oxygen. The reason for adjusting is to supply an appropriate amount of oxygen to the aerobic microorganisms so that the microorganisms grow well.
However, when the dissolved oxygen concentration is monitored by a measuring device using a diaphragm type dissolved oxygen electrode, the following problems may occur.

The diaphragm 10 of the diaphragm type dissolved oxygen electrode is
As shown in FIG. 6 , the pinhole 22 may be formed due to contact with the SS component in the water to be treated. Such a pinhole 22 is likely to occur at a portion of the diaphragm 10 facing the detection electrode 6, and in that case, the treated water 2 passes through the pinhole 22.
A large amount of dissolved oxygen in 0 reaches the surface of the detection electrode 6 freely, and as a result, the indicated value of the measuring device increases. If the amount of aeration to the water to be treated is reduced or the aeration is stopped accordingly, the amount of oxygen supplied to the microorganisms decreases, resulting in an oxygen deficiency state and the microorganisms die.

The diaphragm 10 of the diaphragm type dissolved oxygen electrode has a
As shown in FIG. 7 , a tear 24 may occur due to stress or fatigue applied to the diaphragm. Such a tear 24
Is likely to occur in the vicinity of the contact portion with the support tube 2, in which case the electric resistance of the liquid existing between the detection electrode 6 and the diaphragm 10 becomes small, and a current not involving dissolved oxygen is generated in the detection electrode 6 and the counter electrode 8.
And the measured value increases as a result. Reduce the amount of aeration to the water to be treated accordingly,
If the aeration is stopped, the oxygen supply amount to the microorganisms is reduced, resulting in an oxygen deficiency state and killing the microorganisms.

Therefore, in the sewage treatment facility, the damage of the diaphragm of the diaphragm type dissolved oxygen electrode is detected, and when the indicated value of the measuring device rises due to the damage of the diaphragm, the amount of aeration to the water to be treated is reduced. However, it has been desired to prevent the aeration from being stopped, but conventionally, there has been no simple and effective means for detecting the breakage of the diaphragm of the diaphragm-type dissolved oxygen electrode. Further, if a large current continues to flow between the detection electrode and the counter electrode in a state where the film is damaged, stains may be deposited on the detection electrode and the counter electrode and the detection electrode and the counter electrode may be damaged.

The present invention has been made in view of the above circumstances, and an electrode main body in which a detection electrode and a counter electrode are installed inside a support tube and the tip opening of the support tube is closed by a gas permeable diaphragm. a membrane electrode enclosing an internal fluid inside of the purpose thereof is to provide a membrane electrode having a membrane breakage detection means for detecting the breakage of the gas permeable membrane.

[0008]

Means for Solving the Problems The present invention, order to achieve the object, a detection electrode and a counter electrode inside supporting region pipe installed,
A diaphragm-type electrode in which an internal liquid is enclosed in an electrode body formed by closing the tip opening of the support tube with a gas-permeable diaphragm, and a diaphragm breakage detection electrode is provided outside the electrode body. and, to provide a membrane type electrode and detecting the breakage of the gas permeable membrane based on a change of the resulting voltage (including generation) between the septum damage detection electrode and the electrode body .

[0009]

In the diaphragm electrode of the present invention, the diaphragm breakage detection electrode is provided outside the electrode body.
Between the diaphragm breakage detection electrode and the electrode body when the membrane is not damaged is electrically insulated by the support tube and the diaphragm, have voltage such raw Ji therebetween. However, when the diaphragm is a pinhole or tear occurs in the membrane is damaged, between the pin holes or via a tear membrane breakage detection electrode and the electrode body are electrically connected, Ji voltage live therebetween It Thus, if monitoring the voltage between the diaphragm breakage detection electrode and the electrode body, it can clearly detect the breakage of the diaphragm based on the occurrence and the change of the electric pressure (increase).

[0011]

The type of the diaphragm electrode of the present invention is not limited,
An electrode that applies a voltage between the detection electrode and the counter electrode may be used, or a galvanic cell type electrode that does not apply a voltage may be used. In the case of an electrode to which no voltage is applied, the battery is composed of the detection electrode, the internal liquid and the counter electrode. Specifically, the diaphragm electrode of the present invention can be configured as a polarographic or galvanic cell type dissolved oxygen electrode, a dissolved hydrogen electrode, a chlorine electrode in water, and the like.

The support tube, the detection electrode, the counter electrode, the diaphragm breakage detection electrode, the diaphragm, the material and composition of the internal liquid are not limited, and can be arbitrarily determined according to the type of electrode. For example, when the diaphragm electrode of the present invention is configured as a dissolved oxygen electrode, the detection electrode is Au or Pt, the counter electrode is Ag / AgCl, the diaphragm breakage detection electrode is Ag, and the diaphragm is FEP (tetrafluoroethylene hexafluoropropylene). A fluororesin film such as a copolymer film, and the internal liquid may be KCl or KOH.

The location of the diaphragm breakage detection electrode is not limited, but a diaphragm breakage detection electrode is embedded in the peripheral wall of the support tube, or a fixing member for fixing the diaphragm to the support tube is made of metal, The electrode itself can be configured as a diaphragm damage detection electrode. Membrane damage detection electrodes occurs voltage between preferably be located as close as possible to the diaphragm, thereby diaphragm breakage detection electrode and the electrode body
It is more reliably detected.

The diaphragm type electrode of the present invention comprises a gas permeable diaphragm.
When a breakage is detected, a measuring mark between the detection electrode and the counter electrode
The applied voltage can be set to zero or the detection wiring can be cut off.
If this is done, the detection electrode
A large current does not continue to flow between the counter electrode and the counter electrode. Na
The diaphragm-type electrode of the present invention is used when a membrane breakage is detected.
A warning signal may be emitted.

Further, the constitution of the means for making the applied voltage for measurement between the detection electrode and the counter electrode to zero and the means for cutting off the detection wiring can be arbitrarily determined. For example, as the former means, there is a means for making the power supply of the voltage applying power supply device zero, and as the latter means, a switch such as a relay is connected to the detection wiring, and the detection wiring is cut off by this switch. There is a means to do.

In the above case, when the diaphragm electrode applies an applied voltage between the detection electrode and the counter electrode, when the breakage of the gas permeable diaphragm is detected, the voltage between the detection electrode and the counter electrode is increased. Zero the applied voltage for measurement or cut off the detection wiring. When the diaphragm electrode does not apply an applied voltage between the detection electrode and the counter electrode, the detection wiring is cut off when the breakage of the gas-permeable diaphragm is detected.

[0018]

Preferred embodiments of the diaphragm electrode of the present invention include the following first and second embodiments. [First Embodiment] A detection electrode and a counter electrode, which are connected to each other by a detection wiring, are installed inside a supporting tube, and the inside of an electrode body is formed by closing the tip opening of the supporting tube with a gas permeable diaphragm. A diaphragm type electrode enclosing a liquid, the third electrode being installed outside the electrode body for detecting diaphragm damage, the diaphragm damage detecting wire connecting the third electrode to the detecting wire, and the diaphragm damage detecting And a voltmeter connected to the wiring for use in the diaphragm type electrode, which detects breakage of the gas permeable diaphragm based on a change in voltage detected by the voltmeter.

FIG. 1 shows the first embodiment, and in FIG.
Reference numeral 0 is a third electrode for detecting a membrane breakage provided outside the electrode body 12, 32 is a diaphragm breakage detection wiring for connecting the third electrode 30 to the detection wiring 4, and 34 is a diaphragm breakage detection wiring. Shows a voltmeter. In FIG. 1, the same components as those in FIG. 11 are designated by the same reference numerals and the description thereof will be omitted.

In the first embodiment, the voltage between the detection electrode 6 and the third electrode 30 is detected by the voltmeter 34, and the breakage of the gas permeable diaphragm 10 is detected based on the generation and change of this voltage. This point will be further described as follows.
FIG. 2 shows an equivalent circuit of the first embodiment. In FIG.
6 is a detection electrode, 8 is a counter electrode, 30 is a third electrode, R ₁ is a resistance between the detection electrode 6 and the counter electrode 8, R ₂ is a resistance between the detection electrode 6 and the third electrode 30, and R ₃ is a counter electrode 8 and the third electrode 30. The resistance between the three electrodes 30 is shown.
When the diaphragm is not damaged (normal), R ₂ and R ₃ are infinite due to the presence of the support tube and the diaphragm.

Now, assuming that the potential of the detection electrode 6 is -0.7 V and the potential of the counter electrode 8 is 0 V, the voltage detected by the voltmeter 34 is 0 V in a normal state, but the diaphragm is damaged. When pinholes and tear occurs Te, no longer by R ₂ and R ₃ is infinite, a voltage of approximately the voltmeter 34 -0.7 volts is detected. Therefore, the breakage of the diaphragm can be detected based on the generation or change of the voltage between the detection electrode 6 and the third electrode 30.

Strictly speaking, however, the values of R ₂ and R ₃ differ depending on the location and the state of the membrane damage, so the magnitude of the generated voltage may vary. Further, when the materials of the electrodes 6, 8 and 10 are different, each of the electrodes 6, 8 and 10 has its own electric potential, and thus the magnitude of the generated voltage may vary. However, the threshold value of the voltage for judging the film damage is [zero] or [present], and in almost all the experimental examples, the applied voltage (−0.7 V) is observed. It does not matter in practice.

The first embodiment has the advantages that the method for detecting film breakage is simple and that the threshold value of the voltage for judging film breakage can be set easily. When detecting the current generated between the diaphragm breakage detection electrode and the inside of the electrode body, if the test liquid is highly pure water such as ultrapure water, the current may not flow easily. When detecting the voltage generated between the breakage detection electrode and the electrode body, it is possible to reliably detect film breakage even if the test liquid is highly pure water such as ultrapure water. There are advantages.

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[ Second Embodiment] FIG. 3 is a circuit diagram showing a means for disconnecting wiring for detection of a diaphragm electrode according to a second embodiment. In this circuit, when the damage to the gas-permeable diaphragm is detected by the diaphragm damage detecting means, the wiring for breaking is cut off by the wiring break switch.

[0035]

EXAMPLE FIG. 4 is a sectional view showing an example of the diaphragm electrode of the first embodiment. 4 , parts having the same configurations as those in FIGS. 1 and 2 are designated by the same reference numerals, and the description thereof will be omitted. However, in FIG. 4 , 50 is a lead-out connector, 52 is a temperature measuring element such as a thermistor, and 54 is a diaphragm fixing nut.

The diaphragm type electrode of FIG. 4 is an example in which the diaphragm breakage detection electrode 30 is embedded in the peripheral wall portion of the support tube 2 in the first embodiment .

[0037]

As described above, according to the diaphragm type electrode of the present invention, the breakage of the gas permeable diaphragm can be detected easily and surely .

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a diaphragm-type electrode according to a first embodiment.

FIG. 2 is an equivalent circuit diagram of the first embodiment.

FIG. 3 is a circuit diagram showing a means for disconnecting wiring for detection of a diaphragm-type electrode according to a second embodiment.

FIG. 4 is a cross-sectional view showing an example of the diaphragm electrode of the first embodiment.

FIG. 5 is a configuration diagram showing an example of a conventional diaphragm electrode.

FIG. 6 is an explanatory diagram showing a state in which a pinhole is formed in the diaphragm of the electrode.

FIG. 7 is an explanatory diagram showing a state in which the diaphragm of the electrode is broken.

[Explanation of symbols]

2 Support tube 4 Detection wiring 6 detection poles 8 opposite poles 10 Gas permeable diaphragm 12 electrode body 18 Internal liquid 30 Third electrode 32 Diaphragm breakage detection wiring 34 Voltmeter 38 power supply 40 Fourth electrode 42 power supply

Claims (3)

(57) [Claims] 1. A diaphragm-type electrode in which an internal liquid is sealed in an electrode body, in which a detection electrode and a counter electrode are installed inside a supporting tube, and the tip opening of the supporting tube is closed by a gas-permeable diaphragm. there are, to exist outside of the electrode body installed diaphragm breakage detection electrode, the breakage of the gas permeable membrane based on a change of the resulting voltage between the septum damage detection electrode and the electrode body Diaphragm type electrode characterized by detecting. 2. An internal liquid is provided inside an electrode body in which a detection electrode and a counter electrode connected by a detection wiring are installed inside a support tube, and the tip opening of the support tube is closed by a gas permeable diaphragm. A diaphragm type electrode encapsulating, a third electrode for detecting a diaphragm break installed outside the electrode body, a diaphragm break detecting wire connecting the third electrode to the detecting wire, and a diaphragm break detecting wire. The membrane-type electrode according to claim 1, further comprising a voltmeter connected to the wiring, wherein damage to the gas-permeable membrane is detected based on a change in voltage detected by the voltmeter. 3. When damage to the gas permeable membrane is detected
To zero the applied voltage for measurement between the detection electrode and the counter electrode
3. The partition according to claim 1 or 2, which interrupts the detection wiring.
Membrane electrode.