JPH03197858A - Inspecting method for corrosion state of body buried underground - Google Patents
Inspecting method for corrosion state of body buried undergroundInfo
- Publication number
- JPH03197858A JPH03197858A JP33925789A JP33925789A JPH03197858A JP H03197858 A JPH03197858 A JP H03197858A JP 33925789 A JP33925789 A JP 33925789A JP 33925789 A JP33925789 A JP 33925789A JP H03197858 A JPH03197858 A JP H03197858A
- Authority
- JP
- Japan
- Prior art keywords
- underground
- potential
- corrosion
- current
- switch
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000005260 corrosion Methods 0.000 title claims abstract description 51
- 230000007797 corrosion Effects 0.000 title claims abstract description 38
- 238000000034 method Methods 0.000 title claims description 10
- 238000005259 measurement Methods 0.000 claims abstract description 15
- 238000009434 installation Methods 0.000 claims 3
- 229910000831 Steel Inorganic materials 0.000 abstract description 8
- 239000010959 steel Substances 0.000 abstract description 8
- 238000007689 inspection Methods 0.000 abstract description 3
- 238000010586 diagram Methods 0.000 description 8
- 238000004210 cathodic protection Methods 0.000 description 5
- 238000002474 experimental method Methods 0.000 description 5
- 238000000576 coating method Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 231100000989 no adverse effect Toxicity 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- 230000000007 visual effect Effects 0.000 description 2
- 229910001018 Cast iron Inorganic materials 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000009412 basement excavation Methods 0.000 description 1
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical class [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 1
- 238000005536 corrosion prevention Methods 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は、地中に埋設された鋼管またはタンクなどのよ
うな導電性を有する地中埋設物の防食状況を検査するた
めの方法に関する。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for inspecting the corrosion protection status of electrically conductive underground objects such as steel pipes or tanks buried underground.
従来の技術
地中埋設管は、電車レールからの漏れ電流である迷走電
流および各種のマクロセル要因による腐食から管体を守
るため、一般に電気絶縁性の塗覆装が施されている。こ
のような塗覆装は、掘削工事によって傷付けられたり、
経年とともに劣化したりする。そのためガスを輸送する
地中埋設管などでは、その鋼管に防食電流を流して、電
気防食法が行われている。BACKGROUND OF THE INVENTION Underground pipes are generally coated with an electrically insulating coating to protect them from corrosion caused by stray currents leaking from train rails and various macrocell factors. Such coatings may be damaged by excavation work,
It deteriorates over time. For this reason, cathodic protection is applied to underground pipes that transport gas by passing an anticorrosion current through the steel pipes.
このような電気防食法において、電気防食を行っている
地中埋設物に防食電流が流れて防食が行われているかど
うかおよび電気防食を行っていない他の地中埋設管にお
いて、電気防食による影響がないかどうかを常時、２４
時間にわたって測定する必要がある。In this type of cathodic protection method, whether or not an anticorrosion current is flowing through underground pipes that are undergoing cathodic protection and corrosion protection is being achieved, and the effects of cathodic protection on other underground pipes that are not undergoing cathodic protection. Always check if there is 24
Must be measured over time.
従来では、このような継続的に地中埋設管の防食状況の
検査は実際上、行われていない。Conventionally, such continuous inspection of the corrosion protection status of underground pipes has not actually been carried out.
発明が解決すべき課題
本発明の目的は、地中埋設物の防食状況を長期間にわた
り、継続して検査することができるようにした地中埋設
物の防食状況の検査方法を提供することである。Problems to be Solved by the Invention An object of the present invention is to provide a method for inspecting the corrosion protection status of underground buried objects that enables continuous inspection of the corrosion protection status of underground objects over a long period of time. be.
課題を解決するための手段
本発明は、地中埋設物に外部電源によって防食電流を流
して防食を行う地中埋設物の防食状況の検査方法におい
て、
外部電源による地中埋設物への防食電流を供給／遮断し
、防食電流の供給時と遮断時とにおける地中埋設物の対
地電位の電位差を測定し、この測定結果に基づいて、地
中埋設物の防食状況の検査をすることを特徴とする地中
埋設物の防食状況の検査方法である。Means for Solving the Problems The present invention provides a method for inspecting the corrosion protection status of underground objects, which performs corrosion protection by passing an anti-corrosion current through an underground object using an external power source. It is characterized by supplying/cutting off the corrosion protection current, measuring the difference in potential to the ground of the underground object when the anticorrosion current is supplied and cut off, and inspecting the corrosion protection status of the underground object based on the measurement results. This is a method for inspecting the corrosion protection status of underground objects.
また本発明は、防食電流の供給時と遮断時とにおける地
中埋設物の対地電位を、メモリにストアしておき、前記
メモリのストア内容を処理回路によって演算処理して前
記電位差を求めることを特徴とする。The present invention also provides a method of storing the potential to the ground of underground objects in a memory when the anticorrosive current is supplied and when the anticorrosion current is cut off, and calculating the potential difference by processing the stored contents of the memory using a processing circuit. Features.
作 用
本発明に従えば、地中埋設物には外部電源によって防食
電流を流して防食を行っており、この防食電流を供給お
よび遮断し、供給時における地中埋設物の対地電位と、
遮断時における地中埋設物の対地電位との電位差を測定
し、この測定結果に基づいて地中埋設物の防食状況の検
査を行うことができる。Function According to the present invention, corrosion protection is carried out by passing an anticorrosive current through an underground object by an external power source, and this anticorrosive current is supplied and cut off to adjust the ground potential of the underground object at the time of supply,
The potential difference with the ground potential of the underground object at the time of interruption is measured, and the corrosion protection status of the underground object can be inspected based on the measurement result.
本件発明者の実験によれば、地中埋設物がたとえば電気
絶縁性塗覆装を有する鋼管であって、その鋼管に防食電
流が流されて防食を行っているときの対地電位は、土壌
中を流れる防食電流によって発生する電圧降下分を含ん
で計測されるため、防食電流の供給時の方が、防食電流
の遮断時に比べて３５０ｍＶ以上さらに負である電位、
たとえば−１０００ｍＶなどであることが好ましい、ま
た防食電流が流されていない地中埋設物では、その防食
電流が流されていない地中埋設物の近傍における防食電
流が流されている他の地中埋設物への防食電流の供給時
と遮断時とにおいて、防食電流が流されていない地中埋
設物の前記電位差は、本件発明者の実験によれば、でき
るだけ小さい値であることが好ましい。このようにして
地中埋設物の防食状況を長期間にわたって自動的に検査
することが可能である。According to experiments conducted by the inventor of the present invention, when the underground object is, for example, a steel pipe with an electrically insulating coating, and an anticorrosion current is applied to the steel pipe to prevent corrosion, the ground potential in the soil is Since the measurement includes the voltage drop caused by the anti-corrosion current flowing through, the potential when the anti-corrosion current is supplied is 350 mV or more more negative than when the anti-corrosion current is cut off.
For example, -1000 mV is preferable, and in the case of an underground object to which no anti-corrosion current is being applied, other underground objects near the underground object to which the anti-corrosion current is being applied are According to experiments conducted by the inventor of the present invention, it is preferable that the potential difference between when the anticorrosive current is supplied to the buried object and when it is cut off to the underground object to which the anticorrosive current is not applied is as small as possible. In this way, it is possible to automatically inspect the corrosion protection status of underground objects over a long period of time.
また本発明に従えば、防食電流の供給時と遮断時とにお
ける地中埋設物の対地電位を測定してメモリにストアし
ておき、このようなメモリにストアされている内容を、
たとえば操作者が自分の会社に持帰って、マイクロコン
ピュータなどによって実現される処理回路を用いて演算
処理し、前記電位差を求めることができる。この電位差
の時間経過に伴う変化を観察することによって、電車レ
ールなどからの迷走電流の悪影響がない深夜において、
防食状況を正確に判断することが可能である。Further, according to the present invention, the ground potential of the underground object is measured when the anticorrosive current is supplied and when it is cut off and stored in a memory, and the contents stored in such memory are
For example, the operator can take it back to his or her office and perform arithmetic processing using a processing circuit realized by a microcomputer or the like to determine the potential difference. By observing changes in this potential difference over time, it is possible to detect late-night situations when there is no adverse effect from stray currents from train rails, etc.
It is possible to accurately judge the corrosion protection status.
実施例
第１（２１は本発明の一実施例の断面図である。地面の
道路１には地中埋設管２が埋設されている。Embodiment 1 (21 is a sectional view of an embodiment of the present invention. An underground pipe 2 is buried in a road 1 on the ground.
この地中埋設管２は鋼管の外周面に塗覆装が施されて構
成される。地中埋設管２の鋼管には、直流外部電源３の
負極が接続されている。この電源３の正極は、タイマス
イッチ４を介して、地中に埋設された通電用電極５に接
続される。この通電用電極５は、高硅素鋳鉄またはフェ
ライトなどの材料から成る。外部電源３は、たとえば６
０Ｖ、５０Ａである。このようにして外部電源３によっ
て地中埋設管２には防食電流が流されて、防食が行われ
る。This underground pipe 2 is constructed by coating the outer peripheral surface of a steel pipe. A negative electrode of an external DC power supply 3 is connected to the steel pipe of the underground pipe 2 . The positive electrode of this power source 3 is connected via a timer switch 4 to a current-carrying electrode 5 buried underground. This current-carrying electrode 5 is made of a material such as high silicon cast iron or ferrite. The external power supply 3 is, for example, 6
It is 0V and 50A. In this way, an anticorrosion current is applied to the underground pipe 2 by the external power source 3, and corrosion protection is performed.
地中埋設管２の長手方向に沿って、人孔である縦孔６が
設けられる。この縦孔６はｌ ６ ａによって塞いで交
通の障害になることを防いでおり、縦孔６内には、電位
測定手段７が設けられ、長期間、たとえば２４時間にわ
たって、地中埋設管２の対地電位を継続してストアする
ことができる。A vertical hole 6, which is a manhole, is provided along the longitudinal direction of the underground pipe 2. This vertical hole 6 is blocked by l 6 a to prevent it from becoming an obstacle to traffic, and a potential measuring means 7 is provided in the vertical hole 6 to measure the underground pipe 2 over a long period of time, for example, 24 hours. The ground potential of can be stored continuously.
タイマスイッチ４は、制御回路８によって導通および遮
断が繰返し行われる。このスイッチ４の導通によって防
食電流が供給されるときおよびスイッチ４が遮断されて
防食電流が遮断されるときとにおける地中埋設管２の対
地電位は、電位測定手段７において測定され、ストアさ
れる。The timer switch 4 is repeatedly turned on and off by the control circuit 8 . The potential to the ground of the underground pipe 2 when the switch 4 is turned on to supply the anti-corrosion current and when the switch 4 is turned off and the anti-corrosion current is cut off is measured by the potential measuring means 7 and stored. .
第２図は電位測定手段７のブロック図である。FIG. 2 is a block diagram of the potential measuring means 7.
マイクロコンピュータなどによって実現される処理回路
９はライン１０を介して地中埋設管２の鋼管に接続され
る。もう１つのライン１１は縦孔６内に設けられた電極
１３に接続される。電極１３は、たとえば飽和硫酸銅電
極であってもよく、あるいはまたこの電極１３として、
縦孔６の近傍で地中に設けられたマグネシウム電極など
であってもよい、処理回路９では、地中埋設管２の測定
された対地電位を測定してメモリ１２にサンプリングし
てストアする。この電位測定手段７は、電池によって電
力付勢され、縦孔６内に設けられているので、長期間に
わたって継続して電位の測定が可能である。A processing circuit 9 realized by a microcomputer or the like is connected to the steel pipe of the underground pipe 2 via a line 10. Another line 11 is connected to an electrode 13 provided in the vertical hole 6. The electrode 13 may be, for example, a saturated copper sulfate electrode, or alternatively as this electrode 13
The processing circuit 9, which may be a magnesium electrode installed underground near the vertical hole 6, measures the ground potential of the underground pipe 2, samples it, and stores it in the memory 12. Since this potential measuring means 7 is powered by a battery and is provided within the vertical hole 6, it is possible to continuously measure the potential over a long period of time.
第３図は、本発明の全体の構成を示すブロック図である
。電位測定手段７によって時間経過に伴う電位を測定し
た後には、操作者はその電位測定手段７を自分の会社な
どに持帰り、そのメモリ１２にストアされている電位を
マイクロコンピュータなどによって実現される処理回路
１３に転送し、そのデータファイルの作成を、作成回路
１４において行う。この作成回路１４は、地中埋設管２
に関する防食施設、路線名、測定などに関する情報が入
力手段１５によって入力され、こうしてデータがストア
されてファイルされる。演算回路１６では、作成回路１
４からのデータに基づき、その解析すべきデータファイ
ルの選定、すなわち処理する路線名および測定点の選定
を行い、解析図表の選定・作成回路１７において、防食
電流の供給時と遮断時とにおける地中埋設管２の対地電
位の電位差を図表などにプリンタ１８によって印字し、
また陰極線管などの目視表示手段１９によって表示する
。さらにまたこのような測定された電位はフロッピィデ
ィスク２０にストアして保存することができる。FIG. 3 is a block diagram showing the overall configuration of the present invention. After measuring the electric potential over time using the electric potential measuring means 7, the operator takes the electric potential measuring means 7 back to his or her office and uses the electric potential stored in the memory 12 to be realized by a microcomputer or the like. The data is transferred to the processing circuit 13, and the creation circuit 14 creates the data file. This creation circuit 14 is based on the underground pipe 2
Information regarding corrosion protection facilities, route names, measurements, etc., is input by the input means 15, and the data is thus stored and filed. In the arithmetic circuit 16, the creation circuit 1
Based on the data from 4, the data file to be analyzed is selected, that is, the line name and measurement point to be processed are selected, and the analysis chart selection/creation circuit 17 calculates the The potential difference between the ground potentials of the underground pipe 2 is printed on a chart or the like by the printer 18,
Further, it is displayed by a visual display means 19 such as a cathode ray tube. Furthermore, such measured potentials can be stored and saved on floppy disk 20.
第４図は、電位測定手段７を用いて地中埋設管２の電位
を測定するときの状態を示すグラフである０期間Ｗ１で
はスイッチ４は制御回路８によって導通されており、こ
の期間Ｗ１はたとえば３分間である１次の期間Ｗ２では
、スイッチ４は遮断しており、この期間Ｗ２はたとえば
１分間である。FIG. 4 is a graph showing the state when measuring the potential of the underground pipe 2 using the potential measuring means 7. During the zero period W1, the switch 4 is turned on by the control circuit 8; During the primary period W2, which is, for example, three minutes, the switch 4 is cut off, and this period W2 is, for example, one minute.
電位測定手段７の処理回路９は１５分間にわたり、スイ
ッチ４が期間Ｗ１において導通され、期間Ｗ２において
遮断されるサイクルが繰返し行われるときにおける１秒
毎の電位測定値をメモリ１２にストアする。したがって
１５分間においては、メモリ２には合計９００個の電位
測定値がストアされることになる。スイッチ４が導通さ
れて地中埋設管２に防食電流が流されることによって、
その地中埋設管２の対地電位は鉄の自然電位たとえば５
００〜−７００ｍＶよりもたとえば３５０ｍＶ以上負で
ある電位、たとえば−１０００ｍＶ以上負であることが
、防食の観点から好ましい、スイッチ４が遮断されるこ
とによって地中埋設管２の電位は、土壌中を流れる防食
電流によって発生する電圧降下の影響のない対地電位を
示す、この電位差ΔＥａは本件発明者の実験によれば前
述のように、３５０ｍＶ以上の絶対値であることが好ま
しい。For 15 minutes, the processing circuit 9 of the potential measuring means 7 stores in the memory 12 potential measurements every second when the switch 4 is repeatedly turned on during the period W1 and cut off during the period W2. Therefore, in 15 minutes, a total of 900 potential measurement values are stored in the memory 2. When the switch 4 is turned on and the anti-corrosion current is passed through the underground pipe 2,
The ground potential of the underground pipe 2 is the natural potential of iron, for example 5
It is preferable from the viewpoint of corrosion prevention that the potential is, for example, 350 mV or more negative than 00 to -700 mV, for example, -1000 mV or more negative. When the switch 4 is shut off, the potential of the underground pipe 2 is lowered through the soil. This potential difference ΔEa, which indicates a potential to the ground that is not affected by the voltage drop caused by the flowing anticorrosion current, preferably has an absolute value of 350 mV or more, as described above, according to the experiments conducted by the inventor of the present invention.
第４図では、スイッチ４が遮断しているときにおける地
中埋設管２の対地、電位は■２で示されており、スイッ
チ４が導通しているときにおける地中埋設管２の対地電
位はＶｌで示されており、それらの電位差ΔＥａは、
ΔＥａ＝Ｖ１−Ｖ２ ＝（１）地中埋設管
２の途中にたとえば電気絶縁管継手２１が設けられてい
るときには、ライン１０に接続されている地中埋設管２
の部分には外部電源３から防食電流が流れることはない
。このときには、第５図で示されるようにスイッチ４が
導通される期間Ｗ１および遮断される期間Ｗ２における
非防食地中埋設管２の電位差ΔＥｂができるだけ小さい
こと、本件発明者の実験によればたとえば５０ｍＶ未満
であることが好ましい。In FIG. 4, the potential to the ground of the underground pipe 2 when the switch 4 is cut off is indicated by ■2, and the potential to the ground of the underground pipe 2 when the switch 4 is conductive is Vl, and their potential difference ΔEa is as follows: ΔEa = V1 - V2 = (1) For example, when an electrically insulating pipe joint 21 is provided in the middle of the underground pipe 2, it is connected to the line 10. Underground pipe 2
No anti-corrosion current flows from the external power supply 3 to the part. At this time, as shown in FIG. 5, the potential difference ΔEb of the non-corrosion-proof underground pipe 2 during the period W1 in which the switch 4 is turned on and the period W2 in which it is cut off is as small as possible.According to the experiments of the present inventor, for example, Preferably it is less than 50 mV.
スイッチ４が導通しているときにおける地中埋設管２の
対地電位はＶ３で示されており、スイッチ４が遮断して
いるときにおける地中埋設管２の対地電位は■４で示さ
れており、これらの電位差ΔＥｂは、
ΔＥｂ＝Ｖ３−Ｖ４ ・・・ （
２）このような非防食地中埋設管２に関してもまた上述
と同様にして、１５分間にわたり合計９００個の電位測
定値がメモリ１２にストアされる。The ground potential of the underground pipe 2 when the switch 4 is conducting is shown by V3, and the ground potential of the underground pipe 2 when the switch 4 is cut off is shown by ■4. , the potential difference ΔEb between them is ΔEb=V3-V4... (
2) For such a non-corrosion-protected underground pipe 2, a total of 900 potential measurements are stored in the memory 12 over a period of 15 minutes in the same manner as described above.
処理回路１３では、メモリ１４にストアされている電位
測定値に基づき、合計９００個の電位測定値の平均値Ｘ
を求め、また電位の高い方から１ｏｏｉの電位測定値の
平均値ｘ１を求め、また電位の低い方から１００個の電
位測定値の平均値Ｘ２を作成回路１４において演算し、
これによって第３式および第４式を求める。In the processing circuit 13, based on the potential measurement values stored in the memory 14, the average value X of a total of 900 potential measurement values is calculated.
In addition, the average value x1 of 100 measured potential values from the higher potential is calculated, and the average value X2 of 100 potential measured values from the lower potential is calculated in the creation circuit 14.
Accordingly, the third equation and the fourth equation are obtained.
ｘｉ−ｘ−ΔＥ１ ・・・（３）ｘ２−ｘ
−ΔＥ２ ・ （４）防食電流が流され
ている地中埋設管２であるときには、第６図のように、
データ数のグラフが得られ、また非防食地中埋設管２で
あるときには第７図で示されるデータ数のグラフが得ら
れる。すなわち、
ΔＥｌｌ＜ｌΔＥ２１ ・・・（５）であるとき
には、地中埋設管２に防食電流が供給されている場合で
あり、
ΔＥｌｌ＞ｌΔＥ２１ ・・・（６）であると
きには、地中埋設管２が非防食であるときの状況を表す
、このことから、地中埋設管２に防食電流が流されてい
るか、または非防食状況であるかを判断することができ
る。しかもその電位差ΔＥａ、ΔＥｂを観察することに
よって、適切な防食状況にあるかどうかを判断すること
ができる。xi-x-ΔE1...(3)x2-x
-ΔE2 ・ (4) When it is an underground pipe 2 through which anti-corrosion current is flowing, as shown in Fig. 6,
A graph of the number of data is obtained, and when the pipe is a non-corrosion-proof underground pipe 2, a graph of the number of data shown in FIG. 7 is obtained. That is, when ΔEll<lΔE21 (5), the anticorrosive current is being supplied to the underground pipe 2, and when ΔEll>lΔE21 (6), the underground pipe 2 represents a situation when the underground pipe 2 is not protected from corrosion. From this, it can be determined whether a corrosion protection current is being applied to the underground pipe 2 or whether it is in a non-corrosion protection state. Moreover, by observing the potential differences ΔEa and ΔEb, it is possible to judge whether or not an appropriate corrosion protection situation exists.
第８図はプリンタ１８によって記録紙上に印字された状
態を示しており、この記録結果は、地中埋設管２に防食
電流が流されているときにおける電位の時間経過をグラ
フで表している。スイッチ４を遮断しているときにおけ
る地中埋設管２の対地電位Ｖｌ（第４図参照）のうち最
も高い値（最貴値）はこの実験では一９８０ｍＶであり
、スイッチ４が導通しているときにおける地中埋設管２
の対地電位■２の最も低い値（最卑値）は−１８５０ｍ
Ｖであることなどが、−覧表によって明瞭に知ることが
できる。FIG. 8 shows the state printed on the recording paper by the printer 18, and the recorded result is a graph representing the time course of the potential when the anticorrosive current is flowing through the underground pipe 2. The highest value (the noblest value) of the ground potential Vl (see Figure 4) of the underground pipe 2 when the switch 4 is cut off is -980 mV in this experiment, and the switch 4 is conducting. Underground pipes 2
The lowest value (lowest value) of the ground potential ■2 is -1850 m
It can be clearly seen from the - list that it is V.
第９図は地中埋設管２が非防食であるときにおけるプリ
ンタ１８の印字結果を同様に示している。FIG. 9 similarly shows the printing results of the printer 18 when the underground pipe 2 is not corrosion-protected.
これらの第８図および第９図の地中埋設管２の対地電位
は深夜、たとえばこの実験結果では、午前２時２０分〜
２時３５分の間において測定されており、したがって電
車軌道などによる迷走電流による悪影響が存在しない、
これに対して第１０図に示されるように午ｒ＆ ６時〜
６時１５分における電気防食された地中埋設管２の第８
図に対応する対地電位は、たとえば第１０図に示されて
いるとおり迷走電流によって地中埋設管２の対地電位が
変動する。したがって地中埋設管２の防食状況の測定は
、深夜において、迷走＄流による悪影響が存在しない時
間帯で行う。The potential to the ground of the underground pipe 2 in FIGS. 8 and 9 is late at night, for example, from 2:20 a.m. in this experimental result.
The measurements were taken between 2:35 p.m., so there is no negative effect from stray currents from train tracks, etc.
On the other hand, as shown in Figure 10, from 6:00 p.m.
No. 8 of cathodic-protected underground pipe 2 at 06:15
Regarding the ground potential corresponding to the figure, for example, as shown in FIG. 10, the ground potential of the underground pipe 2 fluctuates due to stray current. Therefore, the corrosion protection status of the underground pipe 2 is measured late at night, at a time when there is no adverse effect due to stray $flow.
本発明は、地中埋設管だけでなく、地中に埋設されたタ
ンクおよびその他の導電性物体の防食状況を検査するた
めに、広範囲に実施することができる。The present invention can be widely implemented to inspect the corrosion protection status of underground pipes as well as underground tanks and other conductive objects.
発明の効果
以上のように本発明によれば、防食電流の供給時と遮断
時とにおける地中埋設物の対地電位の電位差を測定し、
この測定結果に基づいて地中埋設物の防食状況の検査を
行うことができるので、長期間にわたって自動的に防食
状況の検査を行うことが可能である。しかも本発明によ
れば、防食電流の供給時と遮断時とにおける地中埋設物
の対地電位をメモリにストアしておき、このメモリを操
作者がたとえば自分の会社に持帰って処理回路に接続し
てメモリのストア内容を演算処理し、前記電位差を求め
、たとえばその電位差の時間経過を観察することができ
る。Effects of the Invention As described above, according to the present invention, the difference in potential to the ground of an underground object is measured when the anticorrosive current is supplied and when it is cut off.
Since the corrosion protection status of underground objects can be inspected based on the measurement results, it is possible to automatically inspect the corrosion protection status over a long period of time. Moreover, according to the present invention, the potential to the ground of underground objects when the anticorrosion current is supplied and cut off is stored in a memory, and the operator can take this memory back to his/her company and connect it to the processing circuit. It is possible to perform arithmetic processing on the contents stored in the memory, obtain the potential difference, and observe, for example, the elapse of the potential difference over time.
第１図は本発明の一実施例の全体の系統図、第２図は電
位測定手段７の具体的な構成を示す電気回路図、第３図
は電位測定手段７が接続される処理装置１３の電気的構
成を示すブロック図、第４図は地中埋設管２が電気防食
されているときにおけるスイッチ４の導通／遮断時の対
地電位の変化を示すグラフ、第５図は地中埋設管２が非
防食であるときにおけるスイッチ４を導通／遮断したと
きの対地電位を示すグラフ、第６図は地中埋設管２が電
気防食されているときにおける対地電位の測定結果を示
すグラフ、第７図は地中埋設管２が非防食であるときに
おける対地電位の測定結果を示すグラフ、第８図はプリ
ンタ１８によって電気防食されている地中埋設管２に関
連する印字状態を示す図、第９図はプリンタ１８による
地中埋設管２が非防食であるときにおける印字結果を示
す図、第１０図は電気防食されている地中埋設管２の迷
走電流による悪影響の状態を示す対地電位を示すグラフ
である。
１・・・地面、２・・・地中埋設管、３・・・外部電源
、４・・・タイマスイッチ、５・・・通電用電極、６・
・・縦孔、７・・・電位測定手段、８・・・制御手段、
９・・・処理回路、１２・・・メモリ、１３・・・照合
電極、１３ａ・・・処理回路、１４・・・データファイ
ル作成回路、１５・・・入力回路、１６・・・解析デー
タファイル選定回路、１７・・・解析図表の選定作成回
路、１”８・・・プリンタ、１９・・・目視表示手段、
２０・・・フロッピディスク（イ立FIG. 1 is an overall system diagram of an embodiment of the present invention, FIG. 2 is an electric circuit diagram showing a specific configuration of the potential measuring means 7, and FIG. 3 is a processing device 13 to which the potential measuring means 7 is connected. A block diagram showing the electrical configuration of the underground pipe 2, Fig. 4 is a graph showing the change in ground potential when the switch 4 is turned on/off when the underground pipe 2 is cathodic-protected, and Fig. 5 is a graph showing the change in ground potential when the underground pipe 2 is electrically protected. Figure 6 is a graph showing the potential to ground when the switch 4 is turned on/off when the underground pipe 2 is non-corrosion protected; FIG. 7 is a graph showing the measurement results of the ground potential when the underground pipe 2 is not corrosion-protected, and FIG. 8 is a diagram showing the printing state related to the underground pipe 2 which is cathodic-protected by the printer 18. FIG. 9 is a diagram showing the printing result by the printer 18 when the underground pipe 2 is non-corrosion-protected, and FIG. 10 is a diagram showing the state of the adverse effect of stray current on the underground pipe 2 which is cathodic-protected. This is a graph showing. DESCRIPTION OF SYMBOLS 1...Ground, 2...Underground pipe, 3...External power supply, 4...Timer switch, 5...Electrifying electrode, 6...
... Vertical hole, 7... Potential measuring means, 8... Control means,
9... Processing circuit, 12... Memory, 13... Reference electrode, 13a... Processing circuit, 14... Data file creation circuit, 15... Input circuit, 16... Analysis data file Selection circuit, 17... Analysis chart selection creation circuit, 1"8... Printer, 19... Visual display means,
20... Floppy disk (stand up)
Claims (2)
防食を行う地中埋設物の防食状況の検査方法において、 外部電源による地中埋設物への防食電流を供給／遮断し
、防食電流の供給時と遮断時とにおける地中埋設物の対
地電位の電位差を測定し、この測定結果に基づいて、地
中埋設物の防食状況の検査をすることを特徴とする地中
埋設物の防食状況の検査方法。(1) In a method for inspecting the corrosion protection status of underground objects in which corrosion protection is carried out by passing an anti-corrosion current through an underground object using an external power source, supplying/cutting off the anti-corrosion current to the underground object using an external power source, An underground installation characterized by measuring the potential difference between the ground potential of the underground installation when an anticorrosive current is supplied and when it is cut off, and inspecting the corrosion protection status of the underground installation based on the measurement results. Method for inspecting corrosion protection status.
の対地電位を、メモリにストアしておき、前記メモリの
ストア内容を処理回路によつて演算処理して前記電位差
を求めることを特徴とする特許請求の範囲第１項記載の
地中埋設物の防食状況の検査方法。(2) The ground potential of the underground object when the anticorrosive current is supplied and cut off is stored in a memory, and the contents stored in the memory are processed by a processing circuit to obtain the potential difference. A method for inspecting the corrosion protection status of underground objects as set forth in claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33925789A JPH03197858A (en) | 1989-12-26 | 1989-12-26 | Inspecting method for corrosion state of body buried underground |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33925789A JPH03197858A (en) | 1989-12-26 | 1989-12-26 | Inspecting method for corrosion state of body buried underground |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03197858A true JPH03197858A (en) | 1991-08-29 |
Family
ID=18325738
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP33925789A Pending JPH03197858A (en) | 1989-12-26 | 1989-12-26 | Inspecting method for corrosion state of body buried underground |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03197858A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5404104A (en) * | 1992-03-11 | 1995-04-04 | Agip S.P.A. - Snam S.P.A. | Device and method for monitoring and locating defects in, and detachment of, the protective covering of underground or immersed metal structures or pipelines |
| JP2007033133A (en) * | 2005-07-25 | 2007-02-08 | Nippon Steel Engineering Co Ltd | Method and system for monitoring corrosion prevention state |
| JP2007071712A (en) * | 2005-09-07 | 2007-03-22 | Tokyo Gas Co Ltd | Soundness evaluation device, soundness remote evaluation system, soundness evaluation method and soundness evaluation program for anticorrosion-objective pipeline |
| JP2008196947A (en) * | 2007-02-13 | 2008-08-28 | Tokyo Gas Co Ltd | Abnormal low grounding spot detection method and detection system of buried metal pipeline |
| JP2009198242A (en) * | 2008-02-20 | 2009-09-03 | Tokyo Gas Co Ltd | Corrosion risk measuring and evaluating method of embedded metal pipeline |
-
1989
- 1989-12-26 JP JP33925789A patent/JPH03197858A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5404104A (en) * | 1992-03-11 | 1995-04-04 | Agip S.P.A. - Snam S.P.A. | Device and method for monitoring and locating defects in, and detachment of, the protective covering of underground or immersed metal structures or pipelines |
| JP2007033133A (en) * | 2005-07-25 | 2007-02-08 | Nippon Steel Engineering Co Ltd | Method and system for monitoring corrosion prevention state |
| JP4698318B2 (en) * | 2005-07-25 | 2011-06-08 | 新日鉄エンジニアリング株式会社 | Anticorrosion state monitoring method and system |
| JP2007071712A (en) * | 2005-09-07 | 2007-03-22 | Tokyo Gas Co Ltd | Soundness evaluation device, soundness remote evaluation system, soundness evaluation method and soundness evaluation program for anticorrosion-objective pipeline |
| JP2008196947A (en) * | 2007-02-13 | 2008-08-28 | Tokyo Gas Co Ltd | Abnormal low grounding spot detection method and detection system of buried metal pipeline |
| JP2009198242A (en) * | 2008-02-20 | 2009-09-03 | Tokyo Gas Co Ltd | Corrosion risk measuring and evaluating method of embedded metal pipeline |
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