JPS603545A - Electrolytic cell for measuring polarization curve - Google Patents

Abstract

PURPOSE:To measure highly precisely a polarization without any leakage by connecting a vessel for supplying electrolyte to one end part of a double tube, providing a double cylinder to another end part through a connecting valve, pressing an opening part for measurement, and pouring the electrolyte into the double cylinder. CONSTITUTION:A liquid 2 in an electrolytic cell is allowed to flow into the vessel 11 for supplying electrolyte through an inner tube 9b, by closing a connecting valve 19 and driving a pump 13. The liquid 2 is sent to the connecting tube 19 provided at another end part 10b of the double tube 10 from a supplying hole 8a of an outer tube 8, and returns to an electrode vessel 1 through an inner tube 9a. Next, if the measuring opening part 22a of the double cylinder 22 is brought into contact with a material W to be measured through a packing 23 and pressed, the valve 19 is opened by this operation. Thus, the liquid 2 flows down through an outer cylinder 20, then impinges on a surface of the material W and returns. An opening or closing valve 17 is opened, gaseous nitrogen of a deaeration apparatus 16 is bubbled in the liquid 2 for deaeration, driving of the pump 13 is stopped at a time point when the dissolved oxygen concn. of the liquid 2 is lowered to a suitable value, and the polarization is measured.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an electrolysis method for measuring polarization curves that uses the polarization characteristics of metal materials to measure polarization non-destructively without cutting out test pieces at the installation site. Regarding cells.

[Technical background of the invention and its set points]

It has been confirmed that the polarization characteristics of metal materials reflect changes in the structure of the metal material (changes in material properties over time). It is used as a means to detect changes in material properties. That is,
For example, many studies have been proposed on the sensitization and polarization properties of Nutenrenu steel pipes, including electrochemical reactivation methods (E.

P, R method) is widely used.

In general, polarization measurement means cut out a test piece and place it in an electrolyte bath on the polarization side. However, for example, in the case of installed plant piping, etc. It is necessary to measure it non-destructively. In this way, test pieces are cut out at the installation site. An electrolytic cell for measuring analytical curves has been proposed.

That is, in FIG.
A is formed with a diaphragm opening, and a spiral counter electrode (electrode) C is inserted into this diaphragm opening. One end of this counter electrode C is passed through the outer cylinder a and connected to a potentiostat e having a recorder e via a lead wire d, and the end of the counter electrode C is connected to the potentiostat e having a recorder e. A backing f is provided on the part so as to be able to press against the object to be measured (metallic material) W while keeping it watertight. moreover,
The above-mentioned outside 1. located on the surface of the counter electrode C. A reference electrode 1 containing an electrode in a Luggin tube g is vertically installed in the upper part a of the reference electrode 1 in an airtight manner. Furthermore, a lead wire d3 is connected to the potentiostat θ to the object to be measured W, and the electrolytic solution k is injected into the external fla during measurement. It is injected and filled from the injection port a1.Therefore, during polarization measurement, the electrolytic cell for polarization curve measurement described above is brought into close contact with the object W to be measured via the backing fi through the aperture opening of the outer cylinder a. Then, all the electrolyte is injected into the outer cylinder a from the electrolyte inlet a, and then the counter electrode C and the reference electrode 1 are energized, so that the potentiostat e is connected to the reference electrode. The polarization characteristic due to the potential difference between the counter electrode C and the object to be measured W is measured based on the reference potential of No. 1, and this is recorded on a recorder θ.

However, since the above-mentioned electrolytic cell for polarization curve measurement is carried to the installation site and measures a limited and narrow area of the object to be measured, the entire device has to be made smaller and lighter in order to make it more convenient to carry. Because of this, the amount in the electrolyte solution is not too small, but during the measurement of polarization characteristics,
Because ions are eluted into the electrolytic solution k from the object W,
When the capacity of the electrolytic solution in the outer cylinder a3 is small, the composition of the electrolytic solution changes due to the influence of eluted ions, and (8
) It is predicted that the polarization characteristics will not be affected.

Next, when attaching the outer tube a to the object W to be measured, in case A that the contact state of the object W to be measured cannot be sufficiently seen at the installation site due to the location where the measurement point is located at the back or the aperture opening. In such a case, even if there is a minute gap between the backing f and the object to be measured W, this cannot be confirmed.
The electrolytic solution K leaks from the gap, and this leaked electrolytic solution may corrode the area around the object W to be measured. Furthermore, since the outer cylinder a has a structure in which the electrolyte solution kf is injected from the upper electrolyte injection port a, when the outer cylinder a is used upside down with the upper, lower, or reverse direction, Air bubbles enter between the object W to be measured and the electrolytic solution, making it impossible to obtain sufficient contact, making it difficult to actually measure polarization in an upward direction.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and can be installed on the top, bottom, right or left side of the object to be measured at the installation site, and prevents electrolyte from leaking. (4) To provide an electrolytic cell for measuring polarization curves that is capable of performing all polarization measurements with high accuracy.

[Summary of the invention]

The present invention connects each inner tube of a double tube having an outer tube to an electrode bath containing a counter electrode and a reference electrode, and connects an electrolyte supply tank to one end of the double tube. A double cylindrical body is attached to the other end via a connecting valve, a measuring opening for the object to be measured is formed at one end of this mold part, and the connecting valve is opened by pressing this measuring opening. The structure is such that an electrolytic solution can be injected into the double cylinder body.

[Embodiments of the invention]

Hereinafter, the present invention will be described with reference to an illustrated embodiment.

In FIG. 2, reference numeral 1 denotes a sealed electrode tank that holds an electrolytic solution 2, and this electrode tank 1 includes a counter electrode 8 that detects the potential of the electrolytic solution 2, and a reference electrode 4 that holds a reference potential.
is vertically arranged, and the counter electrode 8 and reference electrode 4 are connected to a potentiostat 6 equipped with a recorder 6a via respective lead wires 5a and 5b. Further, a dissolved oxygen meter 7 is installed upright in the electrode tank 1 so as to be able to measure the amount of dissolved oxygen contained in the electrolytic solution 2.

On the other hand, the electrode tank 1 has an outer tube 8 and an inner tube 9a.

The inner tubes 9a and 9b of a double tube 10 configured with 9b are connected, and one end portion 10 a ij of this double tube 10
It is connected to a sealed electrolyte supply tank. or,
One end 9b of the inner tube 9b in the electrolyte supply tank 11.

is provided with a pump 13 equipped with a motor 12,
This pump 13 sucks in the 1F4i solution 2 in the inner tube 9b, and sends the electrolyte 2 that has returned to the electrolyte supply tank 11 to the supply port 8a of the outer tube 8 through the double tube. It has become. Furthermore, an on-off valve 14 such as a solenoid valve is provided in the middle of the outer pipe 8, and an on-off valve 15 such as a solenoid valve is provided on the pipe path of the inner pipe 9b. ing.

On the other hand, in the vicinity of the electrolyte supply tank 11, there is a degassing device 16 for supplying nitrogen gas to the electrolyte to control the amount of dissolved oxygen.
are connected to each other through a communication pipe 18 having an on-off valve 17.

On the other hand, a connecting valve 19 with a closing habit is attached to the other end iob of the double pipe 10, and this connecting valve 19 has a double cylinder body composed of an outer cylinder 20 and an inner cylinder 21. 22 is installed vertically. Also, an O-ring 2 is attached to one end of this double cylinder 22.
The opening 22a is formed so that it can come into watertight contact with the object W to be measured.
+ Constant aperture opening 22a is pressed after coming into contact with the object W to be measured, thereby opening the connecting valve 19 provided at the base of the double cylinder body 22 and allowing the electrolyte 2 to enter from the outer cylinder 20. The liquid is applied so as to be injected into the lower opening 21a of the tube 21. Note that the object to be measured W is equipped with the potentiostat 6.
A series of lead wires connected to the

Hereinafter, the effects of the present invention will be explained in detail.

First, before bringing the measurement opening 22a of the double cylinder body 22 into contact with the object to be measured W, the on-off valves 14 and 15 are opened in advance, and the motor 12 is energized to drive the pump 3. 1・1
Therefore, the valve is closed. By driving the pump 13, the electrolyte 2 in the electrode tank 1 passes through the inner pipe 9b and flows into the above-mentioned It flows into the electrolyte supply tank 11.

Then, the electrolyte 2 in the electrolyte supply tank 11 is fed under pressure from the supply port 8a of the outer tube 8 to the other end of the double tube 10.
The liquid is sent to a connecting pipe 19 provided at nl, and is returned to the electrode tank 1 through an inner pipe 9a connected to this connecting pipe 19. Therefore, as shown in FIG. 3, the electrolytic solution 2 in the double tube 10 does not flow into the double cylinder body 22, and there is no possibility that the electrolytic solution 2I'i will flow out from the measurement opening 22a. do not have.

Next, when the measurement opening 22a of the double cylinder 22 is brought into contact with and pressed against the object W through the backing 23, the double cylinder 22 is fixed to the object W by this action. At the same time, the connecting valve 19 opens.
As shown in the fourth figure, the electrolytic solution 2 in the outer tube 8 flows down from the connecting valve 19 through the outer tube 20, and then collides with the surface of the object W to be measured, and then flows into the inner tube 21. lower opening 21 of
a, and passes through the connecting valve 19 again to the inner pipe 9a.
The liquid is then refluxed to the electrode tank 1. In this case, the electrolytic solution 2 sufficiently contacts the object W to be measured.

On the other hand, as shown in FIG.
Since the electrolytic solution 2 of a is constructed so as to pass through the outer cylinder and into the inner cylinder 2, there is no risk of the electrolytic solution leaking to the outside.

On the other hand, by fully opening the on-off valve 17, an appropriate amount of nitrogen gas from the deaerator 16 is bubbled into the electrolyte 2 in the electrolyte supply tank 11 through the communication pipe 18 for deaeration. ``While the electrolyte continues to circulate, the dissolved oxygen meter 7 detects and measures the amount of dissolved oxygen.

In this case, a gap 25 is generated between the backing 23 and the object W to be measured, and when air is sucked through the gap 25, the dissolved oxygen concentration increases significantly, resulting in poor attachment to the object W. The condition can be easily detected.

Next, when the dissolved oxygen concentration of the electrolytic solution 2 drops to an appropriate level (1M), the on-off valve 14.t5kf2-i is turned on, the motor 12 is de-energized, and the pump 13
Stops driving. With this, polarization measurement is performed in the same manner as in the specific example described above.

That is, by energizing the counter electrode 3 and the reference electrode 4, the potentiostat 6 measures the polarization characteristics due to the potential difference between the counter electrode 8 and the object to be measured W based on the base potential of the reference electrode 4. and force it to be recorded on the recorder 6a.

Furthermore, since the electrode 'JyR1 has a sufficient capacity t, there is no possibility that it will be affected by ion elution during polarization measurement.

Next, after the polarization measurement, when the on-off valves 1, 4, and 15'i are opened, the pump 13 is simultaneously operated to circulate the electrolyte.

In this manner, by separating the measurement opening 22a from the object to be measured W while circulating the electrolyte, the electrolyte in the double cylinder body 22 passes through the inner cylinder 21 and reaches the connecting valve 19. At the same time, the connecting valve 19 closes and returns to the state shown in the third portion.

Since the electrolytic solution in the electrolytic solution supply tank 11 is stored in a large capacity, the ions eluted during polarization measurement that have refluxed are further diluted, so that the electrolytic solution can be removed without replacing the electrolytic solution. The next continuous operation of polarization measurement can be carried out immediately.

[Embodiments of the invention]

As described above, according to the present invention, the inner tubes 9a and 9b of the double tube 10 having the outer tube 8 are connected to the electrode bath 1 containing the counter electrode 8 and the reference electrode 4. One end 10
A is connected to the electrolyte supply tank 11, a double mounting body 22 is attached to the land end tob of the double pipe 10 via a connecting valve 19, and a measuring object is attached to one end of this 2N cylinder 22. By forming the measurement opening 22a of the object W and pressing the measurement opening 22a, the connection valve 19 is fully opened and the electrolyte is supplied. It is not only possible to measure the polarization of the object W non-destructively, it is easy to handle, and the leakage of the electrolyte is strong, so there is no risk of corroding the cover of the object W, and furthermore, Since sufficient electrolyte is used, the accuracy of polarization measurement can be improved.

(11)

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an electrolytic cell for measuring polarization curves that has already been proposed, FIG. 2 is a sectional view diagrammatically showing an electrolytic cell for measuring polarization curves according to the present invention, and FIGS. The figures are diagrams for explaining the present invention in detail. 1... Electrolytic cell, 2... Electrolyte, 3... Counter electrode, 4...
... Verification electrode, 6... Potentiometer F, 8-/
AM, 9a. 9b...Inner pipe, IO...Double pipe, 14.15...
Opening/closing valve, 16... Deaerator, 19... Communication valve, 20
...Outer cylinder, 21...Inner cylinder, 22...Double cylinder body, 2
3...Backing. Applicant's agent Kiyoshi Inomata (12)

Claims (1)

[Claims] 1. Each inner tube of a double tube having an outer tube is connected to an electrode tank containing a counter electrode and a reference electrode, and one end of the double tube is connected to an electrolyte supply tank. A double cylinder is attached to the bent end of the double pipe via a connecting valve, a measurement opening for the object to be measured is formed at one end of the double cylinder, and this measurement opening is pressed. An electrolytic cell for measuring polarization curves, characterized in that the connecting valve is opened. An electrolytic cell for polarization curve measurement according to claim 1, characterized in that an electrolytic solution is supplied to the outer tube of the λ double tube and the electrolytic solution is refluxed to the inner tube.