JP2002180276A - Electrode for monitoring corrosion prevention and method of monitoring corrosion prevention - Google Patents
Electrode for monitoring corrosion prevention and method of monitoring corrosion preventionInfo
- Publication number
- JP2002180276A JP2002180276A JP2000373718A JP2000373718A JP2002180276A JP 2002180276 A JP2002180276 A JP 2002180276A JP 2000373718 A JP2000373718 A JP 2000373718A JP 2000373718 A JP2000373718 A JP 2000373718A JP 2002180276 A JP2002180276 A JP 2002180276A
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- Prior art keywords
- electrode
- anticorrosion
- open
- corrosion
- hole
- Prior art date
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- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
- Prevention Of Electric Corrosion (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、地中に埋設され陰
極防食の施されている防食被覆鋼材の防食被覆重なり部
の隙間における防食状態を監視する防食監視用電極及び
防食監視方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anticorrosion monitoring electrode for monitoring the state of anticorrosion in gaps between anticorrosion coatings of a corrosion protection coating steel material buried in the ground and subjected to cathodic protection, and a method of monitoring anticorrosion. is there.
【０００２】[0002]
【従来の技術】電気防食としては、金属構造物に陰極
（カソード）電流を通じて防食する陰極防食が一般的で
あり、この陰極防食には、外部電源法（外電法ともい
う）と、犠牲陽極法（流電陽極法ともいう）の２方式が
ある。図５は陰極防食の２方式を説明する図であり、同
図の（ａ）は外部電極法を、（ｂ）は犠牲陽極法を説明
する図である。2. Description of the Related Art Cathodic protection, in which a metal structure is protected by passing a cathodic (cathode) current through a metal structure, is generally used. The cathodic protection includes an external power supply method (also referred to as an external power method) and a sacrificial anode method. (Also referred to as galvanic anode method). FIGS. 5A and 5B are diagrams illustrating two methods of cathodic protection, wherein FIG. 5A illustrates the external electrode method and FIG. 5B illustrates the sacrificial anode method.
【０００３】外部電極法は、図５（ａ）のように、例え
ば商用電源を整流して直流電源３ａとし、不溶性の電極
（図示の対極２ａ）を正極として、被防食体１ａを負極
（カソード）として、正極から負極に通電する。この場
合、通電する電流値が適当な値となるように出力電圧値
を調整する。犠牲陽極法は、図５（ｂ）のように、例え
ば亜鉛、アルミニウム、マグネシウム合金等の犠牲陽極
２ｂの溶解に伴って発生する電流を被防食体１ａに通電
する。この場合、出力調整用の可変抵抗器によりなる出
力調整器３ｂの抵抗値を調整して通電する電流値を調整
する。In the external electrode method, as shown in FIG. 5 (a), for example, a commercial power supply is rectified to be a DC power supply 3a, an insoluble electrode (a counter electrode 2a shown) is used as a positive electrode, and the anticorrosion-protected body 1a is used as a negative electrode (cathode). ), A current is passed from the positive electrode to the negative electrode. In this case, the output voltage value is adjusted so that the value of the supplied current becomes an appropriate value. In the sacrificial anode method, as shown in FIG. 5 (b), a current generated as the sacrificial anode 2b made of, for example, zinc, aluminum, or a magnesium alloy is melted is supplied to the anticorrosion target 1a. In this case, the resistance value of the output adjuster 3b, which is a variable resistor for output adjustment, is adjusted to adjust the current value to be supplied.
【０００４】図６は従来の防食電位測定法を説明する図
である。図６において、１は地中に埋設された防食被覆
鋼材、２は対極又は犠牲陽極、３は直流電源又は出力調
整器、４は疑似部材、５は参照電極、７は常時閉で、動
作時に開となるスイッチ、８は電流計、９は電圧計、１
３は鋼材露出部である。従来、地中に埋設され電気防食
が施されている被防食体（この例では防食被覆鋼材１）
の防食管理法として、地中に埋設されている被防食体と
地表面に配設されている参照電極５との間の電位差を計
測する防食電位を用いていた。FIG. 6 is a view for explaining a conventional method for measuring the anticorrosion potential. In FIG. 6, 1 is an anticorrosion coated steel material buried underground, 2 is a counter electrode or a sacrificial anode, 3 is a DC power supply or output regulator, 4 is a pseudo member, 5 is a reference electrode, 7 is normally closed, Open switch, 8 is ammeter, 9 is voltmeter, 1
Reference numeral 3 denotes a steel material exposed portion. Conventionally, an anticorrosion-protected body buried in the ground and subjected to electrolytic protection (corrosion-protected coated steel material 1 in this example)
As the anticorrosion control method, an anticorrosion potential for measuring a potential difference between an anticorrosion target buried underground and a reference electrode 5 disposed on the ground surface has been used.
【０００５】防食電位計測法としては、ＯＮ電位あるい
はＯＦＦ電位による検出方法が一般的である。この方法
は、防食被覆鋼材１と同一材質（この場合鋼）よりなる
小片の疑似部材４を地中の防食被覆鋼材１の近傍に埋
め、通常状態（非測定時）においては、この疑似部材４
を、常時閉のスイッチ７と電流計８を介して防食被覆鋼
材１に短絡させておき、測定時に、スイッチ７を開とし
て短絡状態を切り、この瞬間（１００ｍｓ以内）におけ
る疑似部材４と参照電極５との間の電位差を測定し、こ
れを防食被覆鋼材１の防食電位とするものである。な
お、参照電極５の電位をできるだけ防食被覆鋼材１が埋
設された近傍の電位となるようにして、正確に防食電位
を計測する発明として特開平６−２６５５１１号公報に
示されたものがある。As a method for measuring the anticorrosion potential, a detection method based on an ON potential or an OFF potential is generally used. In this method, a small pseudo member 4 made of the same material (in this case, steel) as the anticorrosion coated steel material 1 is buried near the anticorrosion coated steel material 1 in the ground, and in a normal state (at the time of non-measurement), the pseudo member 4
Is short-circuited to the anticorrosion-coated steel material 1 via the normally closed switch 7 and the ammeter 8, and the switch 7 is opened to cut off the short-circuit state at the time of measurement, and the pseudo member 4 and the reference electrode at this moment (within 100 ms) 5 is measured, and this is used as the anticorrosion potential of the anticorrosion-coated steel material 1. Japanese Patent Application Laid-Open No. 6-265511 discloses an invention in which the potential of the reference electrode 5 is set as close as possible to the potential where the anticorrosion-coated steel material 1 is buried, and the anticorrosion potential is accurately measured.
【０００６】図７は防食被覆鋼材に発生する欠陥の種類
ないし態様を説明する図である。同図の（ａ）は、鋼材
１４の防食被覆１５の一部に破損した箇所があり、その
破損した箇所の防食被覆１５が完全にとれた状態の鋼材
露出部１３が存在する場合であり、（ｂ）は防食被覆の
重なり部における隙間、例えば、防食被覆鋼管の溶接継
手部に施された熱収縮チューブの端がめくれて隙間１６
ができ、この隙間１６から地中の水が流入し、内部が腐
食するような場合である。防食被覆鋼材の欠陥が、図７
（ａ）に示した鋼材露出部１３の場合には、図６に示し
たようにこの鋼材露出部１３に防食電流が流入するの
で、防食効果がある。従って、この鋼材露出部１３があ
る欠陥に対しては、従来の防食電位測定法は、防食被覆
鋼材の防食管理法としても、有効な方法と考えられてい
る。FIG. 7 is a view for explaining the types or modes of defects generated in the corrosion-resistant coated steel material. FIG. 3A shows a case where a part of the anticorrosion coating 15 of the steel material 14 has a damaged portion, and the steel material exposed portion 13 in a state where the anticorrosion coating 15 of the damaged portion is completely removed exists. (B) shows a gap in the overlapping portion of the anticorrosion coating, for example, the end of the heat-shrinkable tube provided at the welded joint portion of the anticorrosion coating steel pipe is turned up and the gap 16 is formed.
This is a case where underground water flows in from the gap 16 and the inside is corroded. The defect of the anticorrosion coated steel material is shown in FIG.
In the case of the steel exposed portion 13 shown in FIG. 6A, the anticorrosion current flows into the steel exposed portion 13 as shown in FIG. Therefore, the conventional method for measuring the anticorrosion potential is considered to be an effective method for controlling the anticorrosion of the anticorrosion-coated steel material with respect to the defect having the steel material exposed portion 13.
【０００７】[0007]
【発明が解決しようとする課題】しかしながら、被防食
体が防食被覆鋼材であり、さらにこの防食被覆鋼材の欠
陥として、図７（ｂ）に示したような防食被覆の隙間
（一般に０．５〜２０ｍｍ程度の隙間）があると多くの
場合、地下水が流入する。地下水があると電気的導電が
できるが、この隙間の大小により、隙間の電気抵抗値が
大きく変わる。すなわち、隙間が小さい場合には、電気
抵抗が大きいので、防食電流はこの隙間にはあまり流入
しない。さらに地中には、電気鉄道を起点とする迷走電
流が存在し防食被覆の隙間から、この迷走電流が流出す
る。このため、隙間に流入する防食電流は少ないうえ、
迷走電流が流出するので、隙間内部の鋼が腐食すること
が多い。しかし、これまで、この隙間内部の鋼の腐食状
態を外部より計測する方法はなかった。言い換えると、
従来の防食管理技術は、図７（ａ）の鋼材露出部１３の
ような表面の防食被覆１５が完全にオープンとなってい
る欠陥だけにしか適用できなかった。従って、図７
（ｂ）に例示するような、防食重なり部の防食被覆１５
が一部剥離し、しかもその剥離した箇所の防食被覆１５
間の隙間１６を通じて鋼材面１７が外部に連通している
ような欠陥に対しては防食電位を測定することさえ不可
能であった。However, the object to be protected is a corrosion-resistant coated steel material, and the defect of the corrosion-resistant coated steel material is a gap between the corrosion-resistant coating as shown in FIG. If there is a gap of about 20 mm), groundwater flows in many cases. Electrical conductivity can be obtained when groundwater is present, but the size of the gap greatly changes the electrical resistance value of the gap. That is, when the gap is small, the electric resistance is large, so that the anticorrosion current does not flow much into this gap. Further, there is a stray current starting from the electric railway in the ground, and the stray current flows out from a gap of the anticorrosion coating. Therefore, the anticorrosion current flowing into the gap is small,
Since the stray current flows out, the steel inside the gap often corrodes. However, there has been no method for measuring the corrosion state of the steel inside the gap from outside. In other words,
The conventional anticorrosion management technique can be applied only to a defect in which the anticorrosion coating 15 on the surface is completely open, such as the exposed steel part 13 in FIG. Therefore, FIG.
(B) As shown in FIG.
Is partly peeled off, and the anticorrosion coating 15 at the part where the part is peeled off
Even for a defect in which the steel surface 17 communicates with the outside through the gap 16 between them, it was not even possible to measure the anticorrosion potential.
【０００８】この問題に対する一つの解決策が特開平２
０００−１９２２６５号公報にて提案されている。この
方法は、防食重なり部の防食被覆間の隙間と等価な状態
を電極部に形成するものである。しかし、この方法によ
り防食電位等を測定することにより防食管理を行うこと
はできるが、防食被覆鋼材の腐食の進行度合すなわち、
腐食速度を測定するものではなかった。One solution to this problem is disclosed in
000-192265. According to this method, a state equivalent to the gap between the anticorrosion coatings of the anticorrosion overlap portion is formed on the electrode portion. However, it is possible to perform anticorrosion management by measuring the anticorrosion potential and the like by this method, but the degree of progress of corrosion of the anticorrosion coated steel material, that is,
It did not measure the corrosion rate.
【０００９】本発明は、前記のような問題点を解決する
ためになされたものであり、防食被覆鋼材の防食被覆重
なり部の隙間内部の欠陥に対しても適用することがで
き、しかも腐食速度を正確に検知することができる防食
監視用電極及び防食監視方法を提供することを目的とす
る。The present invention has been made in order to solve the above-mentioned problems, and can be applied to a defect inside a gap of an anticorrosion coating overlapping portion of an anticorrosion coating steel material, and furthermore, has a high corrosion rate. It is an object of the present invention to provide an anticorrosion monitoring electrode and an anticorrosion monitoring method that can accurately detect the corrosion.
【００１０】[0010]
【課題を解決するための手段】本発明に係る防食監視用
電極は、地中に埋設され陰極防食が施されている防食被
覆鋼材の防食状況を監視する電極において、防食被覆鋼
材の防食被覆重なり部の隙間の大きさをシミュレートし
た穴を有する有底筒状部材と、前記有底筒状部材の前記
穴の内部に配設された、オープンループ状の電極と、参
照電極と、前記オープンループ状の電極に通じる電流の
向きと電流密度及び前記オープンループ状の電極と参照
電極との間の電位を測定する第１の測定回路と、前記第
１の測定回路にスイッチを介して接続され、前記オープ
ンループ状の電極の電気抵抗を測定する第２の測定回路
と、を備えたことを特徴とするものである。SUMMARY OF THE INVENTION An electrode for monitoring corrosion protection according to the present invention is an electrode for monitoring the state of corrosion protection of a steel material buried underground and subjected to cathodic protection. A bottomed tubular member having a hole simulating the size of the gap of the portion, an open-loop electrode disposed inside the hole of the bottomed tubular member, a reference electrode, and the open A first measurement circuit for measuring a direction and a current density of a current flowing to the loop-shaped electrode and a potential between the open-loop electrode and the reference electrode; and a first measurement circuit connected to the first measurement circuit via a switch. And a second measuring circuit for measuring the electric resistance of the open-loop electrode.
【００１１】また、本発明に係る防食監視方法は、地中
に埋設され陰極防食が施されている防食被覆鋼材の防食
状況を監視する方法において、防食被覆鋼材の防食被覆
重なり部の隙間の大きさをシミュレートした穴を有する
有底筒状部材であって、該有底筒状部材の前記穴の内部
にオープンループ状の電極と参照電極を配設した防食監
視用電極を前記防食被覆鋼材の近傍に埋設し、平常時は
前記オープンループ状の電極に通じる電流の向きと電流
密度及び前記オープンループ状の電極と参照電極との間
の電位を測定することにより、前記防食被覆鋼材の防食
状況を監視し、定期的あるいは必要時に前記オープンル
ープ状の電極の電気抵抗を測定することにより、前記防
食被覆鋼材の腐食速度をチェックすることを特徴とする
ものである。Further, according to the present invention, there is provided a method for monitoring the anticorrosion state of an anticorrosion-coated steel material buried underground and subjected to cathodic protection. A cylindrical member having a hole simulating the thickness of the corrosion-resistant coated steel material, wherein the corrosion-resistant monitoring electrode in which an open-loop electrode and a reference electrode are disposed inside the hole of the bottomed cylindrical member. And buried in the vicinity of the anticorrosion-coated steel material by measuring the direction and current density of the current flowing through the open-loop electrode and the potential between the open-loop electrode and the reference electrode in normal times. The corrosion rate of the anticorrosion coated steel material is checked by monitoring the situation and measuring the electric resistance of the open loop electrode periodically or when necessary.
【００１２】まず第１に、本発明においては、有底筒状
部材と、この有底筒状部材に設けた穴の内部に配設さ
れ、防食被覆鋼材と同一材質の線材または帯板からなる
オープンループ状の電極と、参照電極とを備えた防食監
視用電極を用いることに特徴がある。有底筒状部材の穴
は、あらかじめ防食被覆鋼材の防食被覆重なり部の隙間
の大きさをシミュレートすることによって、この穴を通
して流入・流出する電流の抵抗を調整しておく。従っ
て、この穴は電流の抵抗調整部となっている。次に、防
食電位を測定するためのオープンループ状の電極と参照
電極は、前記穴の内部に配設される。ここで、オープン
ループ状の電極とは、例えば、Ｕ型、Ｖ型、Ｗ型、コ字
型、円弧型、あるいは棒状、平板状などの電極形状を有
するものであり、防食被覆鋼材と同一材質の線材または
帯板からなるものである。すなわち、この防食監視用電
極は、オープンループ状の電極に通じる電流の向きと電
流密度及びオープンループ状の電極と参照電極との間の
電位を測定する第１の測定回路と、この第１の測定回路
にスイッチを介して接続され、オープンループ状の電極
の電気抵抗を測定する第２の測定回路とを備えている。
そして、このように構成された防食監視用電極を防食被
覆鋼材の近傍に埋設しておき、オープンループ状の電極
と参照電極間の電位を測定することによって、防食被覆
鋼材の防食電位を測定することができる。このとき、非
測定時にはオープンループ状の電極を防食被覆鋼材に短
絡させておき、測定時には前記短絡状態を開放状態にし
て、開放状態になった瞬間におけるオープンループ状の
電極と参照電極との間の電位を測定すると、さらに高精
度で計測できる。一方、オープンループ状の電極の電気
抵抗を測定することによって防食被覆鋼材の腐食の進行
度合（腐食速度）を検知することができる。この原理は
以下のとおりである。金属は腐食によって厚みを減少す
るが、そのときの試料の電気抵抗は長さが一定であれば
断面積に依存するので、試料の厚み減少によって抵抗値
は増大する。表面に付着した腐食生成物の電導度は金属
素地に比べて著しく小さいので抵抗値には影響しない。
従って、腐食前後の金属の電気抵抗を測定することによ
り断面積の変化を求め、腐食量が求められる。よって、
オープンループ状の電極の電気抵抗値から、防食被覆鋼
材の現時点の電気防食状態や腐食の進行度合を正確に確
認かつ予測でき、電気防食対策を的確に行うことができ
る。First, in the present invention, a bottomed tubular member and a wire or a strip of the same material as the anticorrosion-coated steel material are provided inside a hole provided in the bottomed tubular member. It is characterized by using an anticorrosion monitoring electrode including an open loop electrode and a reference electrode. In the hole of the bottomed cylindrical member, the resistance of the current flowing in and out through this hole is adjusted in advance by simulating the size of the gap between the anticorrosion-coated overlapping portions of the anticorrosion-coated steel material. Therefore, this hole is a current resistance adjusting portion. Next, an open loop electrode and a reference electrode for measuring the anticorrosion potential are disposed inside the hole. Here, the open-loop electrode has, for example, an electrode shape such as a U-shaped, V-shaped, W-shaped, U-shaped, arc-shaped, rod-shaped, or flat-shaped electrode, and is made of the same material as the anticorrosion-coated steel material. Consisting of a wire rod or a strip. That is, the anticorrosion monitoring electrode includes a first measurement circuit that measures the direction and current density of a current flowing to the open-loop electrode and the potential between the open-loop electrode and the reference electrode, and the first measurement circuit. A second measurement circuit that is connected to the measurement circuit via a switch and measures the electric resistance of the open-loop electrode.
The anticorrosion monitoring electrode thus configured is buried in the vicinity of the anticorrosion-coated steel material, and the potential between the open-loop electrode and the reference electrode is measured to measure the anticorrosion potential of the anticorrosion-coated steel material. be able to. At this time, the open-loop electrode is short-circuited to the anticorrosion-coated steel material during non-measurement, and the short-circuit state is set to the open state during measurement. By measuring the potential of, the measurement can be performed with higher accuracy. On the other hand, by measuring the electrical resistance of the open-loop electrode, the degree of progress (corrosion rate) of corrosion of the anticorrosion-coated steel material can be detected. The principle is as follows. The thickness of the metal decreases due to corrosion, but the electrical resistance of the sample at that time depends on the cross-sectional area if the length is constant. Therefore, the resistance value increases as the thickness of the sample decreases. Since the conductivity of the corrosion product attached to the surface is significantly smaller than that of the metal substrate, it does not affect the resistance value.
Therefore, the change in cross-sectional area is determined by measuring the electrical resistance of the metal before and after corrosion, and the amount of corrosion is determined. Therefore,
From the electric resistance value of the open-loop electrode, the current state of corrosion protection and the degree of progress of corrosion of the corrosion-resistant coated steel material can be accurately confirmed and predicted, and the measures for corrosion protection can be taken accurately.
【００１３】第２に、本発明は、有底筒状部材からなる
防食監視用電極を用いることによって、防食被覆の隙間
の流入水の水質の変化を推測でき、これによって防食監
視を強化するなど、迅速な電気防食対策を講じることが
できることである。この場合、防食監視用電極は、上向
きとなるように設置して、前記穴の内部をあらかじめ防
食被覆鋼材の設置場所近傍の地下水あるいは土壌の比抵
抗と同等の電解液または電解液をゲル化もしくはゾル化
したもの（以下、同等電解液と称する）で満たしてお
く。このように同等電解液で穴の内部を満たしておくこ
とによって、防食被覆の隙間の流入水の水質変化を防食
電位測定値の変化から知ることができる。従って、前記
同等電解液を穴の内部に十分に満たしておくために、前
記有底筒状部材は、前記穴に連通する拡径された第２の
穴を有し、その第２の穴の底部またはその近傍に前記オ
ープンループ状の電極と参照電極を配設してなる防食監
視用電極とすることが望ましい。また、平常時はオープ
ンループ状の電極に通じる電流の向きと電流密度及びオ
ープンループ状の電極と参照電極との間の電位を測定す
ることにより、防食被覆鋼材の防食状況を監視し、定期
的あるいは必要時にオープンループ状の電極の電気抵抗
を測定することにより、防食被覆鋼材の腐食速度をチェ
ックすればよい。これにより、電気防食管理を万全に実
施することができる。Second, according to the present invention, by using the anticorrosion monitoring electrode formed of a bottomed cylindrical member, it is possible to estimate a change in water quality of the inflow water in the gap of the anticorrosion coating, thereby enhancing anticorrosion monitoring. That is, quick anticorrosion measures can be taken. In this case, the anticorrosion monitoring electrode is installed so as to face upward, and the inside of the hole is preliminarily gelled with an electrolytic solution or an electrolytic solution equivalent to the specific resistance of groundwater or soil near the installation site of the anticorrosion-coated steel material. It is filled with a sol (hereinafter referred to as an equivalent electrolytic solution). By filling the inside of the hole with the equivalent electrolytic solution in this way, the change in the water quality of the inflowing water in the gap of the anticorrosion coating can be known from the change in the measured anticorrosion potential. Therefore, in order to sufficiently fill the inside of the hole with the equivalent electrolytic solution, the bottomed tubular member has a second hole having an enlarged diameter communicating with the hole, and the second hole of the second hole has a large diameter. It is desirable to provide an anticorrosion monitoring electrode in which the open-loop electrode and the reference electrode are provided at or near the bottom. In normal times, the anticorrosion state of the anticorrosion-coated steel material is monitored by measuring the direction and current density of the current flowing through the open-loop electrode and the potential between the open-loop electrode and the reference electrode. Alternatively, the corrosion rate of the anticorrosion-coated steel material may be checked by measuring the electric resistance of the open-loop electrode when necessary. Thereby, the cathodic protection management can be performed thoroughly.
【００１４】[0014]
【発明の実施の形態】以下、本発明の実施の形態を図面
を用いて説明する。図１は本発明の防食監視方法の説明
図であり、図２〜図４は防食監視用電極の構成を示す図
である。Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram of the anticorrosion monitoring method of the present invention, and FIGS. 2 to 4 are diagrams showing the configuration of an anticorrosion monitoring electrode.
【００１５】まず、本発明に係る防食監視用電極の構成
について説明する。この防食監視用電極６は、基本的に
は、図２に示すように有底筒状部材１０に穴１１を設
け、その穴１１の底部または近傍に、例えば、Ｕ型形状
をしたオープンループ状の電極６１と参照電極６２を配
設したものである。穴１１は、防食被覆重なり部の隙間
１６の大きさをシミュレートしたもので、隙間１６の大
きさに応じて穴径Ｄ及び穴の長さＬを調整してある。隙
間１６の大きさは、防食被覆鋼管の場合、通常０．５〜
２０ｍｍ程度であるので、その中から最も頻度の高い隙
間の大きさに合わせるよう穴径等が決められる。First, the configuration of the anticorrosion monitoring electrode according to the present invention will be described. The anticorrosion monitoring electrode 6 basically has a hole 11 in a bottomed cylindrical member 10 as shown in FIG. 2, and a U-shaped open loop shape at or near the bottom of the hole 11. The electrode 61 and the reference electrode 62 are provided. The hole 11 simulates the size of the gap 16 of the anticorrosion coating overlapping portion, and the hole diameter D and the hole length L are adjusted according to the size of the gap 16. The size of the gap 16 is usually 0.5 to
Since it is about 20 mm, the hole diameter and the like are determined so as to match the size of the most frequent gap among the gaps.
【００１６】有底筒状部材１０は、一般的な絶縁材料で
あるプラスチック材料（例えばアクリル樹脂）からなっ
ている。また、有底筒状部材１０は防食監視用電極６を
埋設する際に、土砂や振動、埋設後の土圧などによりオ
ープンループ状の電極６１の変形や破損を防止する。ま
た、オープンループ状の電極６１は防食被覆鋼材１と同
一材質の鋼線からなっている。参照電極６２は耐食性の
高い材料が好ましい。６３、６４はそれぞれオープンル
ープ状の電極６１及び参照電極６２に接続された接続ケ
ーブルである。The bottomed tubular member 10 is made of a plastic material (eg, acrylic resin) which is a general insulating material. Further, when the anticorrosion monitoring electrode 6 is buried, the bottomed tubular member 10 prevents deformation and breakage of the open-loop electrode 61 due to earth and sand, vibration, earth pressure after burying, and the like. The open-loop electrode 61 is made of a steel wire of the same material as the anticorrosion-coated steel material 1. The reference electrode 62 is preferably made of a material having high corrosion resistance. 63 and 64 are connection cables connected to the open-loop electrode 61 and the reference electrode 62, respectively.
【００１７】また、この防食監視用電極６は、好ましく
は図３に示すように構成されている。図４は図３の断面
図である。図１にはこの構成例の防食監視用電極６を示
してある。図３、図４に示す防食監視用電極６の有底筒
状部材１０は、図２のものと同様に、穴径Ｄ及び穴の長
さＬを調整された第１の穴１１と、この穴１１に連通す
る拡径された第２の穴１２を有する。オープンループ状
の電極６１及び参照電極６２は、第２の穴１２を塞ぐ底
板１３に取り付けられ、両電極６１、６２間は、例えば
エポキシ樹脂で絶縁されている。そして、第１の穴１１
は前述したように防食電流の抵抗調整部を構成し、第２
の穴１２は電極室となっており、この電極室１２は同等
電解液で満たされるものである。この防食監視用電極６
は、地中の防食被覆鋼材１の近傍位置に、先端の開口部
１１ａが鉛直方向の上側となる姿勢で設置される。The anticorrosion monitoring electrode 6 is preferably configured as shown in FIG. FIG. 4 is a sectional view of FIG. FIG. 1 shows an anticorrosion monitoring electrode 6 of this configuration example. The bottomed tubular member 10 of the anticorrosion monitoring electrode 6 shown in FIGS. 3 and 4 has a first hole 11 in which a hole diameter D and a hole length L are adjusted, as in FIG. There is an enlarged second hole 12 communicating with the hole 11. The open-loop electrode 61 and the reference electrode 62 are attached to the bottom plate 13 that covers the second hole 12, and the electrodes 61 and 62 are insulated by, for example, epoxy resin. And the first hole 11
Constitutes the resistance adjustment unit for the anticorrosion current as described above, and the second
Hole 12 is an electrode chamber, and this electrode chamber 12 is filled with an equivalent electrolytic solution. This anticorrosion monitoring electrode 6
Is installed at a position near the anticorrosion-coated steel material 1 in the ground so that the opening 11a at the tip is on the upper side in the vertical direction.
【００１８】防食電流抵抗調整部を構成する第１の穴１
１は、その穴径が、防食被覆鋼材の防食被覆重なり部の
隙間１６の電気抵抗値と同一の電気抵抗値となるよう
に、隙間をシミュレートした穴径に製作される。これは
古い防食被覆埋設管を掘り出した際に、防食被覆重なり
部の隙間を実測し（０．５〜２０ｍｍ程度ある）、この
実測値を多数収集したデータに基づき、最も頻度の高い
値、最大値、最小値等をあらかじめ求めておく。そし
て、第１の穴１１を製作する際に、使用条件や客先仕様
等に応じてどの値を採用するかを決定し、この採用した
値の隙間をシミュレートした穴径及び長さで製作するよ
うにしている。First hole 1 constituting anticorrosion current resistance adjusting section
1 is manufactured to have a hole diameter simulating the gap so that the hole diameter becomes the same as the electric resistance value of the gap 16 of the corrosion protection coating overlapping portion of the anticorrosion coating steel material. This is because when excavating an old anticorrosion coating buried pipe, the gap between the anticorrosion coating overlaps is actually measured (about 0.5 to 20 mm), and the most frequent values The value, minimum value, etc. are determined in advance. When the first hole 11 is manufactured, a value to be adopted is determined according to use conditions, customer specifications, and the like, and a gap having the adopted value is manufactured with a simulated hole diameter and length. I am trying to do it.
【００１９】防食電流抵抗調整部（すなわち、第１の
穴）１１は、先端の開口部１１ａが鉛直方向の上側とな
る姿勢に設置されるので、土壌と通電可能となるが、地
中の砂等がこの開口より入らないように、埋設時には、
絶縁材よりなる網や海綿（水分は自由に通過できるよう
に）でカバーや栓をすることが望ましい。そして電極室
を構成する第２の穴１２は同等電解液で満たされる。Since the anticorrosion current resistance adjusting section (that is, the first hole) 11 is installed in such a position that the opening 11a at the tip thereof is on the upper side in the vertical direction, it is possible to conduct electricity with the soil. At the time of burial,
It is desirable to cover or plug with a net made of insulating material or sponge (so that moisture can pass freely). Then, the second hole 12 constituting the electrode chamber is filled with an equivalent electrolyte.
【００２０】電極室すなわち第２の穴１２は、所定容量
の同等電解液の充填可能な空間を有する。また、同等電
解液の注入がしやすいように電極室１２に横穴の注入口
を設けてもよい。この電極室１２の底部には、互いに電
気的に絶縁されたオープンループ状の電極６１及び参照
電極６２が配設され、前記各電極６１、６２にそれぞれ
外部接続ケーブル６３、６４が配線されている。オープ
ンループ状の電極６１及び参照電極６２の電極形状や配
置は特に限定されない。第２の穴１２の底面近くの内周
面に各電極６１、６２を配置してもよい。The electrode chamber, ie, the second hole 12, has a space that can be filled with a predetermined volume of an equivalent electrolyte. Further, an injection hole having a horizontal hole may be provided in the electrode chamber 12 so as to easily inject the same electrolytic solution. At the bottom of the electrode chamber 12, an open-loop electrode 61 and a reference electrode 62 that are electrically insulated from each other are provided, and external connection cables 63 and 64 are wired to the electrodes 61 and 62, respectively. . The electrode shape and arrangement of the open-loop electrode 61 and the reference electrode 62 are not particularly limited. The electrodes 61 and 62 may be arranged on the inner peripheral surface near the bottom surface of the second hole 12.
【００２１】防食監視用電極６は、地中に埋設される際
には、少なくとも電極室１２に同等電解液を注入しオー
プンループ状の電極６１及び参照電極６２の全体を同等
電解液で満たすようにしてから、開口部１１ａを上向き
として、設置する。同等電解液の注入によって、電極室
１２内に配設されたオープンループ状の電極６１及び参
照電極６２の各電極は、同等電解液の電気抵抗を介し
て、また第１の穴１１を介して地中の土壌と通電状態と
なるとともに、被覆隙間の流入水の水質変化を検知する
ことが可能となる。When the anticorrosion monitoring electrode 6 is buried in the ground, at least an equivalent electrolyte is injected into the electrode chamber 12 so that the entire open-loop electrode 61 and the reference electrode 62 are filled with the equivalent electrolyte. After that, the installation is performed with the opening 11a facing upward. By injecting the equivalent electrolyte, each of the open-loop electrode 61 and the reference electrode 62 disposed in the electrode chamber 12 is connected to the corresponding electrode through the electric resistance of the equivalent electrolyte and through the first hole 11. It becomes possible to detect a change in the water quality of the inflowing water in the covering gap as well as the state of electricity conduction with the underground soil.
【００２２】オープンループ状の電極６１は、防食被覆
鋼材１と同一材質の鋼で製作される。そして設置時に同
等電解液の注入される電極室１２内に設けられ、防食被
覆鋼材１と同一材質の鋼で製作されるオープンループ状
の電極６１は、設置後に腐食が生じ、時間経過とともに
腐食状態が進行する。この電極６１の腐食状態は、実際
に地中に埋設され電気防食の施されている防食被覆鋼材
１の防食被覆重なり部の隙間１６から水が流入し、内部
の鋼に生ずる腐食状態と同一状態となるように（腐食状
態をシミュレートするために）生成させるものである。The open-loop electrode 61 is made of the same material as the anticorrosion-coated steel material 1. The open-loop electrode 61 provided in the electrode chamber 12 into which the equivalent electrolytic solution is injected at the time of installation and made of steel of the same material as the anticorrosion-coated steel material 1 is corroded after the installation, and becomes corroded with time. Progresses. The corrosion state of the electrode 61 is the same as the corrosion state generated in the steel inside by the flow of water from the gap 16 of the anticorrosion coating overlapping portion of the anticorrosion coating steel material 1 which is actually buried in the ground and subjected to electrolytic protection. (To simulate the corrosion state).
【００２３】参照電極６２は、例えば鉛、亜鉛、白金、
モリブデン、タングステン等で製作される。なお、この
参照電極６２は、図５と同様に、防食電位を計測する際
の参照電極として用いられるものであるので、同等電解
液の注入される電極室１２に設置されても長期間腐食し
ない材料で製作される。また参照電極６２をオープンル
ープ状の電極６１と共に電極室１２内に配設することに
より、この防食監視用電極６の埋設時に、参照電極６２
は防食被覆鋼材１の近傍に設置されるから、防食電位計
測時に、防食被覆鋼材１への防食電流と土壌抵抗による
ＩＲ損を含まない真の電位計測を行うことができる。The reference electrode 62 is made of, for example, lead, zinc, platinum,
Made of molybdenum, tungsten, etc. Since this reference electrode 62 is used as a reference electrode for measuring the anticorrosion potential, similarly to FIG. 5, even if it is installed in the electrode chamber 12 into which the equivalent electrolyte is injected, it does not corrode for a long time. Made of material. Further, by disposing the reference electrode 62 together with the open loop-shaped electrode 61 in the electrode chamber 12, when the anticorrosion monitoring electrode 6 is embedded,
Is installed in the vicinity of the anticorrosion-coated steel material 1, it is possible to measure a true electric potential that does not include the IR loss due to the anticorrosion current to the anticorrosion-coated steel material 1 and soil resistance when measuring the anticorrosion potential.
【００２４】次に、図１により、防食電位の測定方法を
説明する。図１において、１は地中に埋設された防食被
覆鋼材、２は対極又は犠牲陽極、３は直流電源又は出力
調整器であり、２、３は図５で説明した外部電極法又は
犠牲陽極法のいずれの電気防食でもよいことを示してい
る。６は前記のように構成された防食監視用電極、７は
常時閉で、動作時に開となるスイッチである。８は電流
計、９は電圧計で、これらスイッチ７、電流計８、電圧
計９を有する第１の測定回路２０は、防食被覆鋼材１
と、オープンループ状の電極６１の一方の端子と、参照
電極６２との間に接続されている。また、オープンルー
プ状の電極６１の電気抵抗を測定する第２の測定回路２
２は、電源２３、電流計２４を有し、スイッチ２５、２
６を介して前記第１の測定回路２０とオープンループ状
の電極６１の他方の端子との間に接続されている。図
中、１６は図７の（ｂ）に示した防食被覆重なり部の隙
間である。Next, a method of measuring the anticorrosion potential will be described with reference to FIG. In FIG. 1, reference numeral 1 denotes an anticorrosion-coated steel buried underground, 2 denotes a counter electrode or a sacrificial anode, 3 denotes a DC power supply or an output regulator, and 2 and 3 denote an external electrode method or a sacrificial anode method described with reference to FIG. Indicates that any of the above-mentioned cathodic protection may be used. Reference numeral 6 denotes an anticorrosion monitoring electrode configured as described above, and reference numeral 7 denotes a switch which is normally closed and opened during operation. Reference numeral 8 denotes an ammeter, 9 denotes a voltmeter, and a first measurement circuit 20 having the switch 7, the ammeter 8, and the voltmeter 9 is used for the anticorrosion-coated steel 1
And one terminal of the open-loop electrode 61 and the reference electrode 62. A second measuring circuit 2 for measuring the electric resistance of the open-loop electrode 61
2 has a power supply 23, an ammeter 24, and switches 25, 2
6 is connected between the first measuring circuit 20 and the other terminal of the open-loop-shaped electrode 61. In the drawing, reference numeral 16 denotes a gap between the anticorrosion coating overlapping portions shown in FIG.
【００２５】通常状態（非測定時）においては、オープ
ンループ状の電極６１は、スイッチ７の常時閉回路及び
電流計８を介して防食被覆鋼材１に短絡されている。ま
た防食監視用電極６は、防食被覆鋼材１の近傍に設置さ
れている。そしてオープンループ状の電極６１に通じる
電流の向きを測定し、該電極６１に電流が流入していれ
ば防食されており、電流が流出していれば腐食が生じて
おり、防食されていないと判定する。また電流密度を測
定し、防食電流が有効に流れていることを監視する。ま
た防食電位計測時には、スイッチ７の回路を開として短
絡状態を切り、この開放状態になった瞬間（１００ｍｓ
以内）における電極６１と参照電極６２との間の電位差
を測定し、これを防食被覆鋼材１の防食電位として求め
るものである。通常、防食被覆鋼材が軟鋼の場合、電位
を銅／硫酸銅電極を基準として−８５０ｍＶ以下に保て
ば防食電流が流れて腐食を防ぐ。以上の測定は第１の測
定回路２０を用いて行う。In a normal state (at the time of non-measurement), the open-loop electrode 61 is short-circuited to the anticorrosion-coated steel material 1 via the normally closed circuit of the switch 7 and the ammeter 8. Further, the anticorrosion monitoring electrode 6 is installed near the anticorrosion-coated steel material 1. Then, the direction of the current flowing to the open-loop electrode 61 is measured. judge. In addition, the current density is measured to monitor that the anticorrosion current is flowing effectively. When measuring the anticorrosion potential, the circuit of the switch 7 is opened to cut off the short-circuit state, and the moment the switch is opened (100 ms)
) Is measured as the anti-corrosion potential of the anti-corrosion coated steel material 1. Normally, when the anticorrosion-coated steel material is mild steel, if the potential is maintained at -850 mV or less with respect to the copper / copper sulfate electrode, an anticorrosion current flows to prevent corrosion. The above measurement is performed using the first measurement circuit 20.
【００２６】対極又は犠牲陽極２から防食被覆鋼材１に
流れる防食電流は、第１の穴１１からなる防食電流抵抗
調整部を通って電極室１２にも流入し、しかも第１の穴
１１は、図７（ｂ）のような隙間１６の大きさをシミュ
レートして防食電流抵抗を調整したものであるので、こ
のような防食被覆重なり部の隙間内部の欠陥であって
も、前記のように電流の向きと電流密度及び防食電位を
測定することによって、その欠陥の防食状態を正確に監
視することができる。The anti-corrosion current flowing from the counter electrode or the sacrificial anode 2 to the anti-corrosion coated steel material 1 flows into the electrode chamber 12 through the anti-corrosion current resistance adjusting portion composed of the first hole 11, and the first hole 11 Since the anticorrosion current resistance is adjusted by simulating the size of the gap 16 as shown in FIG. 7B, even if such a defect is present inside the gap of the anticorrosion coating overlapping portion, as described above. By measuring the current direction, the current density, and the anticorrosion potential, the anticorrosion state of the defect can be accurately monitored.
【００２７】次に、例えば、電気防食が不十分であるよ
うな場合、防食被覆鋼材１の腐食が進行する。そこで、
腐食の進行度合（腐食速度）を知るために、オープンル
ープ状の電極６１と電源２３、電流計２４との間に第２
の測定回路２２がスイッチ２５、２６を介して接続され
ている。スイッチ７の回路を開として第２の測定回路２
２によって、オープンループ状の電極６１の電気抵抗を
測定し、その測定値（電気抵抗値）から、防食被覆鋼材
１の腐食速度を推定するものである。電気抵抗の測定
は、定期的またはその必要があるときに行えばよく、通
常は、前記のように電流の向きと電流密度及び防食電位
の測定によって電気防食の管理を行っている。そして、
このときのモニターに異常がみられたような場合には、
まず、スイッチ２５、２６をそれぞれａ接点からｂ接点
へ、ｃ接点からｄ接点へ切り替え、スイッチ７の回路を
開としてオープンループ状の電極６１の両端子間で閉ル
ープの電気抵抗測定回路（第２の測定回路）を形成す
る。この回路２２によりオープンループ状の電極６１の
電気抵抗を測定することができ、その電気抵抗値から電
極６１の腐食速度、ひいては防食被覆鋼材１の腐食速度
がわかる。これにより、防食被覆鋼材１の腐食進行状況
を正確に予測することができる。Next, for example, when the corrosion protection is insufficient, the corrosion protection coated steel material 1 progresses. Therefore,
In order to know the degree of corrosion progress (corrosion rate), a second loop is provided between the open loop electrode 61 and the power supply 23 and ammeter 24.
Are connected via switches 25 and 26. The circuit of the switch 7 is opened and the second measuring circuit 2
2, the electric resistance of the open-loop electrode 61 is measured, and the corrosion rate of the anticorrosion-coated steel material 1 is estimated from the measured value (electric resistance value). The measurement of the electric resistance may be performed periodically or when it is necessary. Usually, as described above, the control of the cathodic protection is performed by measuring the current direction, the current density, and the anticorrosion potential. And
If something is wrong with the monitor at this time,
First, the switches 25 and 26 are switched from the a contact to the b contact and from the c contact to the d contact, respectively, and the circuit of the switch 7 is opened to open a closed-loop electric resistance measurement circuit (second circuit) between both terminals of the open-loop electrode 61. Measurement circuit) is formed. With this circuit 22, the electric resistance of the open-loop electrode 61 can be measured, and the corrosion rate of the electrode 61 and thus the corrosion rate of the anticorrosion-coated steel material 1 can be determined from the electric resistance value. Thereby, the progress of corrosion of the anticorrosion-coated steel material 1 can be accurately predicted.
【００２８】[0028]
【実施例】腐食速度計測の実施例を以下に示す。防食監
視用電極には炭素鋼（ＳＳ４００）から製作したＵ字型
電極を用いた。また、比較のために、重量減少の計測用
の試料として、同じ炭素鋼（ＳＳ４００）、１００×１
５０×３．２ｍｍ厚の鋼板を用いた。この試料及びＵ字
型電極を３．５％ＮａＣｌ溶液中に大気中で自然浸漬し
た。Ｕ字型電極は１週間毎に外観観察を行い、全面腐食
していることを確認した後、電極の両端に電圧を印加し
て電気抵抗を測定し、電気抵抗から断面積を計算した。
比較のための試料の鋼板は、３つの試料を同時に前記溶
液に浸漬し、１週間毎に１枚ずつ引き上げ、除錆後、重
量計測を行った。溶液は、１週間毎に新しいものと取り
替えた。重量を計測した後、表面積と密度から腐食速度
を計算した。表１に計算結果を示す。単位は年に換算し
た値である。EXAMPLE An example of corrosion rate measurement will be described below. A U-shaped electrode manufactured from carbon steel (SS400) was used as the anticorrosion monitoring electrode. For comparison, the same carbon steel (SS400), 100 × 1
A 50 × 3.2 mm steel plate was used. The sample and the U-shaped electrode were naturally immersed in a 3.5% NaCl solution in the air. The appearance of the U-shaped electrode was observed every week, and after confirming that the entire surface was corroded, a voltage was applied to both ends of the electrode, the electric resistance was measured, and the cross-sectional area was calculated from the electric resistance.
For comparison, a steel plate of a sample was prepared by immersing three samples in the solution at the same time, pulling up one by one every week, removing rust, and measuring the weight. The solution was replaced with a new one every week. After measuring the weight, the corrosion rate was calculated from the surface area and the density. Table 1 shows the calculation results. The unit is a value converted into a year.
【００２９】[0029]
【表１】 [Table 1]
【００３０】表１より、電気抵抗から計算した腐食速度
と重量減少量から計算した腐食速度はほぼ一致している
ことがわかる。また、錆の無い初期は腐食速度が大き
く、表面が錆で覆われると腐食速度が低下する傾向も一
致した。From Table 1, it can be seen that the corrosion rate calculated from the electric resistance and the corrosion rate calculated from the weight loss almost match. In addition, the corrosion rate was high in the early stage without rust, and the tendency was that the corrosion rate was reduced when the surface was covered with rust.
【００３１】[0031]
【発明の効果】以上説明したように、本発明によれば、
防食被覆鋼材の防食被覆重なり部の隙間の大きさをシミ
ュレートした穴を有する有底筒状部材であって、該有底
筒状部材の穴の内部に配設され、防食被覆鋼材と同一材
質からなるオープンループ状の電極と、参照電極とを備
えた防食監視用電極を用い、この防食監視用電極を防食
被覆鋼材の近傍に埋設して、オープンループ状の電極に
通じる電流の向きと電流密度及びオープンループ状の電
極と参照電極間の電位を測定し、またオープンループ状
の電極の電気抵抗を測定するものであるので、防食被覆
重なり部の隙間内部の欠陥に対しても防食電位測定が可
能であるとともに、オープンループ状の電極の腐食によ
る断面積減少に基づく電気抵抗の増大から防食被覆鋼材
の腐食速度の測定が可能である。また、前記穴またはこ
の穴に連通する拡径された第２の穴に同等電解液を入れ
ておくことにより、防食被覆重なり部の隙間内部の欠陥
と同様の腐食状態をこの防食監視用電極によって再現で
き、その隙間内部の欠陥の腐食状態を地上より検知する
ことが可能である。As described above, according to the present invention,
A bottomed cylindrical member having a hole simulating the size of the gap of the anticorrosion-coated overlapping portion of the anticorrosion-coated steel material, which is disposed inside the hole of the bottomed cylindrical member and has the same material as the anticorrosion-coated steel material. An anticorrosion monitoring electrode provided with an open-loop electrode composed of: and a reference electrode, the anticorrosion monitoring electrode is buried in the vicinity of the anticorrosion-coated steel material, and the direction and current of the current flowing through the open-loop electrode It measures the density and the potential between the open-loop electrode and the reference electrode, and also measures the electrical resistance of the open-loop electrode. It is possible to measure the corrosion rate of the anticorrosion-coated steel material from the increase in the electric resistance based on the decrease in the cross-sectional area due to the corrosion of the open-loop electrode. In addition, by putting an equivalent electrolytic solution into the hole or the second hole having an increased diameter communicating with the hole, the same corrosion state as a defect inside the gap of the anticorrosion coating overlapping portion can be detected by the anticorrosion monitoring electrode. It can be reproduced, and the corrosion state of the defect inside the gap can be detected from the ground.
【図面の簡単な説明】[Brief description of the drawings]
【図１】本発明の防食監視方法の説明図である。FIG. 1 is an explanatory diagram of a corrosion prevention monitoring method of the present invention.
【図２】防食監視用電極の一構成例を示す図である。FIG. 2 is a diagram showing a configuration example of an anticorrosion monitoring electrode.
【図３】防食監視用電極の他の構成例を示す図である。FIG. 3 is a diagram showing another configuration example of the anticorrosion monitoring electrode.
【図４】図３の断面図である。FIG. 4 is a sectional view of FIG. 3;
【図５】陰極防食の２方式を説明する図である。FIG. 5 is a diagram illustrating two methods of cathodic protection.
【図６】従来の防食電位測定法の説明図である。FIG. 6 is an explanatory view of a conventional anticorrosion potential measuring method.
【図７】防食被覆鋼材に発生する欠陥の種類を示す説明
図である。FIG. 7 is an explanatory diagram showing types of defects generated in the corrosion-resistant coated steel material.
１ 防食被覆鋼材 ２ 対極又は犠牲陽極 ３ 直流電源又は出力調整器 ４ 疑似部材 ５ 参照電極 ６ 防食監視用電極 ７ スイッチ ８ 電流計 ９ 電圧計 １０ 有底筒状部材 １１ 第１の穴（防食電流抵抗調整部） １２ 第２の穴（電極室） １６ 防食被覆重なり部の隙間 ２０ 第１の測定回路 ２２ 第２の測定回路 ６１ オープンループ状の電極 ６２ 参照電極 REFERENCE SIGNS LIST 1 anticorrosion coated steel material 2 counter electrode or sacrificial anode 3 DC power supply or output regulator 4 pseudo member 5 reference electrode 6 anticorrosion monitoring electrode 7 switch 8 ammeter 9 voltmeter 10 bottomed cylindrical member 11 first hole (corrosion prevention current resistance) Adjustment unit) 12 Second hole (electrode chamber) 16 Gap between anticorrosion coating overlapping part 20 First measurement circuit 22 Second measurement circuit 61 Open loop electrode 62 Reference electrode
───────────────────────────────────────────────────── フロントページの続き (72)発明者 内田 佳邦 東京都千代田区丸の内一丁目１番２号 日 本鋼管株式会社内 (72)発明者 北川 尚男 東京都千代田区丸の内一丁目１番２号 日 本鋼管株式会社内 (72)発明者 玉田 明宏 東京都千代田区丸の内一丁目１番２号 日 本鋼管株式会社内 (72)発明者 丹下 昌彦 愛知県名古屋市熱田区桜田町19番18号 東 邦瓦斯株式会社内 Ｆターム(参考） 2G060 AA10 AE05 AF06 AF07 AG11 AG13 KA11 4K060 AA02 AA03 BA13 CA04 CA15 EA12 EB01 FA07 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshikuni Uchida 1-1-2 Marunouchi, Chiyoda-ku, Tokyo, Japan Inside the Nippon Kokan Co., Ltd. (72) Inventor Nao Kitagawa 1-2-1, Marunouchi, Chiyoda-ku, Tokyo, Japan (72) Inventor Akihiro Tamada 1-2-1, Marunouchi, Chiyoda-ku, Tokyo, Japan In-house Steel Pipe Co., Ltd. F-term in Gas Co., Ltd. (reference) 2G060 AA10 AE05 AF06 AF07 AG11 AG13 KA11 4K060 AA02 AA03 BA13 CA04 CA15 EA12 EB01 FA07
Claims (5)
防食被覆鋼材の防食状況を監視する電極において、 防食被覆鋼材の防食被覆重なり部の隙間の大きさをシミ
ュレートした穴を有する有底筒状部材と、 前記有底筒状部材の前記穴の内部に配設された、オープ
ンループ状の電極と、参照電極と、 前記オープンループ状の電極に通じる電流の向きと電流
密度及び前記オープンループ状の電極と参照電極との間
の電位を測定する第１の測定回路と、 前記第１の測定回路にスイッチを介して接続され、前記
オープンループ状の電極の電気抵抗を測定する第２の測
定回路と、を備えたことを特徴とする防食監視用電極。1. An electrode for monitoring the anticorrosion state of a corrosion protection coated steel material buried in the ground and subjected to cathodic protection, comprising a hole simulating the size of a gap in a corrosion protection coating overlapping portion of the corrosion protection coating steel material. A bottom tubular member, disposed inside the hole of the bottomed tubular member, an open-loop electrode, a reference electrode, and a direction and a current density of a current passing through the open-loop electrode, and A first measurement circuit that measures a potential between the open-loop electrode and the reference electrode; and a second measurement circuit that is connected to the first measurement circuit via a switch and measures an electric resistance of the open-loop electrode. 2. An electrode for monitoring corrosion prevention, comprising:
覆鋼材と同一材質の線材または帯板からなることと、 前記有底筒状部材の穴は、防食電流の抵抗調整部となっ
ていることと、 前記有底筒状部材は、前記穴に連通する拡径された第２
の穴を有し、その第２の穴の底部又はその近傍に前記オ
ープンループ状の電極と参照電極を配設してなることを
特徴とする請求項１記載の防食監視用電極。2. The open-loop electrode is made of a wire or a strip made of the same material as the anticorrosion-coated steel material, and the hole of the bottomed tubular member is a resistance-adjusting portion for anticorrosion current. And the bottomed tubular member has a second enlarged diameter communicating with the hole.
The anticorrosion monitoring electrode according to claim 1, wherein the electrode has an open loop shape and a reference electrode is provided at or near the bottom of the second hole.
防食被覆鋼材の防食状況を監視する方法において、 防食被覆鋼材の防食被覆重なり部の隙間の大きさをシミ
ュレートした穴を有する有底筒状部材であって、該有底
筒状部材の前記穴の内部にオープンループ状の電極と参
照電極を配設した防食監視用電極を前記防食被覆鋼材の
近傍に埋設し、 平常時は前記オープンループ状の電極に通じる電流の向
きと電流密度及び前記オープンループ状の電極と参照電
極との間の電位を測定することにより、前記防食被覆鋼
材の防食状況を監視し、 定期的あるいは必要時に前記オープンループ状の電極の
電気抵抗を測定することにより、前記防食被覆鋼材の腐
食速度をチェックすることを特徴とする防食監視方法。3. A method for monitoring the anticorrosion condition of a corrosion-resistant coated steel material buried in the ground and subjected to cathodic protection, comprising a hole simulating the size of a gap of the corrosion-resistant coating overlap portion of the corrosion-resistant coated steel material. A bottom cylindrical member, an anticorrosion monitoring electrode in which an open loop electrode and a reference electrode are disposed inside the hole of the bottomed cylindrical member, and embedded in the vicinity of the anticorrosion coated steel material; The anticorrosion state of the anticorrosion-coated steel material is monitored by measuring the direction and current density of the current flowing to the open-loop electrode and the potential between the open-loop electrode and the reference electrode, periodically or when necessary. A corrosion protection monitoring method characterized by checking the corrosion rate of the anticorrosion-coated steel material by measuring the electrical resistance of the open-loop electrode at times.
となるように設置して、前記穴の内部にあらかじめ防食
被覆鋼材の設置場所近傍の地下水あるいは土壌の比抵抗
と同等の電解液または電解液をゲル化もしくはゾル化し
たものを入れてなることを特徴とする請求項３記載の防
食監視方法。4. The anticorrosion monitoring electrode is installed so that the hole faces upward, and an electrolyte or an electrolytic solution having a specific resistance equal to that of groundwater or soil in the vicinity of the installation site of the anticorrosion-coated steel material is previously installed inside the hole. The anticorrosion monitoring method according to claim 3, wherein a gel or sol of the electrolytic solution is contained.
極を防食被覆鋼材に短絡させておき、測定時には前記短
絡状態を開放状態にして、前記開放状態になった瞬間に
おける前記オープンループ状の電極と参照電極との間の
電位を測定することを特徴とする請求項３または請求項
４記載の防食監視方法。5. The non-measured open-loop electrode is short-circuited to the anticorrosion coated steel material during measurement, and the short-circuit state is set to an open state during measurement, and the open-loop electrode at the moment of the open state is closed. The anticorrosion monitoring method according to claim 3 or 4, wherein a potential between the reference electrode and the reference electrode is measured.
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Cited By (4)
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|---|---|---|---|---|
| JP2008285714A (en) * | 2007-05-16 | 2008-11-27 | Jfe Engineering Kk | Cap for preventing water draining in electrode for monitoring corrosion-preventing condition, and electrode for monitoring corrosion-preventing condition |
| US9030204B2 (en) | 2011-07-07 | 2015-05-12 | Seiko Epson Corporation | Sensor device |
| JP2017150075A (en) * | 2011-02-14 | 2017-08-31 | サウジ アラビアン オイル カンパニー | Cathodic Protection Monitoring Probe |
| CN111707606A (en) * | 2020-05-08 | 2020-09-25 | 中国船舶重工集团公司第七二五研究所 | Copper-nickel alloy pipeline internal welding heat affected zone corrosion electrochemical testing device |
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|---|---|---|---|---|
| CN104122307B (en) * | 2013-04-27 | 2017-04-19 | 中国科学院金属研究所 | Multichannel potential measuring instrument |
| US11965818B1 (en) * | 2020-05-28 | 2024-04-23 | Mopeka Products Llc | Corrosion monitor |
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|---|---|---|---|---|
| JPH05118204A (en) * | 1991-10-28 | 1993-05-14 | Niigata Eng Co Ltd | High temperature corrosion monitor for gas turbine |
| JP2000192265A (en) * | 1998-12-25 | 2000-07-11 | Nkk Corp | Protection monitoring electrode and protection monitoring method |
| JP2000192266A (en) * | 1998-12-25 | 2000-07-11 | Nkk Corp | Method for measuring corrosion characteristic of inside of protective coating peeling and apparatus therefor and protection monitoring electrode |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008285714A (en) * | 2007-05-16 | 2008-11-27 | Jfe Engineering Kk | Cap for preventing water draining in electrode for monitoring corrosion-preventing condition, and electrode for monitoring corrosion-preventing condition |
| JP2017150075A (en) * | 2011-02-14 | 2017-08-31 | サウジ アラビアン オイル カンパニー | Cathodic Protection Monitoring Probe |
| US9030204B2 (en) | 2011-07-07 | 2015-05-12 | Seiko Epson Corporation | Sensor device |
| CN111707606A (en) * | 2020-05-08 | 2020-09-25 | 中国船舶重工集团公司第七二五研究所 | Copper-nickel alloy pipeline internal welding heat affected zone corrosion electrochemical testing device |
| CN111707606B (en) * | 2020-05-08 | 2024-03-29 | 中国船舶重工集团公司第七二五研究所 | Electrochemical testing device for corrosion of welding heat affected zone inside copper-nickel alloy pipeline |
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| Publication number | Publication date |
|---|---|
| JP4601155B2 (en) | 2010-12-22 |
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