JP3429650B2 - Method of forming anti-corrosion film on piping or tank inner surface - Google Patents
Method of forming anti-corrosion film on piping or tank inner surfaceInfo
- Publication number
- JP3429650B2 JP3429650B2 JP29347597A JP29347597A JP3429650B2 JP 3429650 B2 JP3429650 B2 JP 3429650B2 JP 29347597 A JP29347597 A JP 29347597A JP 29347597 A JP29347597 A JP 29347597A JP 3429650 B2 JP3429650 B2 JP 3429650B2
- Authority
- JP
- Japan
- Prior art keywords
- film
- tank
- pipe
- electrode
- water
- 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.)
- Expired - Fee Related
Links
- 238000000034 method Methods 0.000 title claims description 11
- 238000005260 corrosion Methods 0.000 title description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 23
- 239000013505 freshwater Substances 0.000 claims description 7
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical compound OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 claims description 5
- 239000012047 saturated solution Substances 0.000 claims description 5
- 239000011575 calcium Substances 0.000 description 15
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 6
- 230000007797 corrosion Effects 0.000 description 6
- 239000007788 liquid Substances 0.000 description 6
- 239000000243 solution Substances 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 5
- 229910001424 calcium ion Inorganic materials 0.000 description 5
- 229910001425 magnesium ion Inorganic materials 0.000 description 5
- 230000001172 regenerating effect Effects 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 229910000019 calcium carbonate Inorganic materials 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 3
- 238000009533 lab test Methods 0.000 description 3
- 238000012423 maintenance Methods 0.000 description 3
- 230000010287 polarization Effects 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 238000005338 heat storage Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 101100160821 Bacillus subtilis (strain 168) yxdJ gene Proteins 0.000 description 1
- 101150096674 C20L gene Proteins 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical group [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 102220543923 Protocadherin-10_F16L_mutation Human genes 0.000 description 1
- 102220491117 Putative postmeiotic segregation increased 2-like protein 1_C23F_mutation Human genes 0.000 description 1
- 101100445889 Vaccinia virus (strain Copenhagen) F16L gene Proteins 0.000 description 1
- 101100445891 Vaccinia virus (strain Western Reserve) VACWR055 gene Proteins 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 238000004378 air conditioning Methods 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 244000005700 microbiome Species 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000010422 painting Methods 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- -1 polyethylene Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000003908 quality control method Methods 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- 239000008234 soft water Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000008399 tap water Substances 0.000 description 1
- 235000020679 tap water Nutrition 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L58/00—Protection of pipes or pipe fittings against corrosion or incrustation
- F16L58/02—Protection of pipes or pipe fittings against corrosion or incrustation by means of internal or external coatings
- F16L58/04—Coatings characterised by the materials used
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Protection Of Pipes Against Damage, Friction, And Corrosion (AREA)
- Preventing Corrosion Or Incrustation Of Metals (AREA)
Description
【発明の詳細な説明】
【０００１】
【発明の属する技術分野】本発明は、開放蓄熱式空調設
備等の所謂淡水を配管もしくはタンク内面に循環させる
ような各種装置における前記配管もしくはタンク内面に
防食皮膜を形成させる方法に関する。
【０００２】
【従来の技術】通常、開放蓄熱式空調設備等の所謂淡水
を配管もしくはタンク内面に循環させるような各種装置
においては、配管もしくはタンク内は常時水中環境にあ
り、建設時には塗装やライニング等で防錆対策が行われ
るが、経年劣化による塗膜損傷部でのマクロセル腐食、
また液中の微生物の繁殖により配管内面の腐食は、0.3
〜0.4mm/yにも達している。メンテナンスとしては配管
もしくはタンク内面を除錆し再塗装するのが一般的であ
るが、実際には水が抜けないため塗装は不可能である。
その他、水質改善として炭酸ガスとCa(OH)2の混合液を
循環させて自然に炭酸カルシウム皮膜を形成させる方法
が行われている。これらの方法も配管もしくはタンク内
面に錆や汚れが付着している状態では十分な付着効果が
得られず、不均一な皮膜状態となり、いずれも防食効果
には大きく期待できないのが現状である。またこれらの
方法は常に水質のpH等の調整が必要であり、メンテナン
スも重要であり、必ずしも経済的な方法ではない。しか
も日本の上水は軟水といわれるようにCa硬度が小さくて
自然には配管もしくはタンク内面に炭酸カルシウムの皮
膜は形成し難い水といえる。これらはCa硬度と水のpH、
Ｍアルカリ度から得られるCaCO3の飽和指数が負となる
ためである。従って今日配管もしくはタンク内面に炭酸
カルシウムの皮膜を均一に付着させるためには、循環水
の水質改善によってCa硬度やＭアルカリ度を高めるため
の人工硬度水が検討され、なおきめ細かなpH、水質成分
の運用管理を含めての重要な検討課題となっている。
【０００３】
【発明が解決しようとする課題】本発明は、開放蓄熱式
空調設備等の所謂淡水を配管もしくはタンク内面に循環
させるような各種装置において、従来安定した防食皮膜
が形成し難かった配管もしくはタンク内面に、均一で良
好な防食皮膜を簡単に形成し得る方法を提供することを
目的とするものである。本発明者はこれら課題のもと、
鋭意検討した結果、水中にCaイオンとMgイオンとを供給
し、同時に外部の直流電源装置から管路、タンク内に配
設した電極部を経由して、配管もしくはタンク内面に直
流電流（カソード電流）を供給することにより、配管も
しくはタンク内壁にCaCO3,Mg(OH)2系の混合した防食皮
膜を形成することができることを知見した。本発明はこ
の知見に基づくものである。
【０００４】
【課題を解決するための手段】すなわち、本発明は、配
管もしくはタンク内の任意の箇所に所定長さの電極部を
取外し可能に取付け、その後配管もしくはタンク内に循
環させる淡水にあらかじめMg(OH)2およびCO2ガスを混入
させて循環水中に重炭酸イオンを形成せしめた後、Ca(O
H)2の飽和液を添加してpHを８〜10に調整するととも
に、外部に設けた直流電源装置から前記電極部に直流電
流を供給することにより、前記配管もしくはタンク内壁
にCaCO3,Mg(OH)2系の混合した防食皮膜を形成させるこ
とを特徴とするものであり、これにより前記課題を達成
したものである。
【０００５】
【発明の実施の形態】本発明において、作用を確認する
ため、および各工程条件を設定するため、図１に示すよ
うな実験室試験を準備した。この試験機において循環液
として水道水２０リットル中にCa(OH)2とMg(OH)2の化合
物を比率を変えて添加し、また通電電流、通電時間を変
えた種々の条件を組合せた一連の試験を行った。
【０００６】図１において、循環液１の途中にセル２を
置き、この中にテストピース３(75×100×1.0mm)と通電
電極４としてPt-Ti電極を置き、別に設けた照合電極５
によりテストピース３の電位を−900mV(SCE)になるよう
にポテンショスタット６にて通電した。通電時間を１、
２、３週間に分けて、期間中の通電電流、分極抵抗、pH
を記録し、それぞれの期間内にテストピース３を引き上
げて表面観察を行った。これらの結果を表１に示す。
【０００７】
【表１】
【０００８】表１における添加成分とは循環水中に添加
される添加物もしくはイオン量を示すものである。ま
た、pH変化とは防食皮膜が付着する際のpH値である。
【０００９】表１より、本発明に従った試験No.2のデー
タが最も良好な皮膜が形成されていることがわかる。す
なわち、循環水中にMg(OH)2を添加し、かつCO2ガスを液
のpHが約６程度となるまで添加する。このCO2ガスの供
給は液中に重炭酸イオンを生成させるためであり、この
重炭酸イオンの増加に伴いＭアルカリ度がより高まり、
次工程であるCa(OH)2の飽和液の供給による皮膜形成を
促進させ、同時に良好な皮膜形成を促す。従ってCO2ガ
スの供給は液中に式１の(a)で示される反応に寄与する
に十分な重炭酸イオン量となるようにし、十分なＭアル
カリ度とすることが必要であり、そのためには液pHがほ
ぼ６程度となるように供給することがおよその目安とな
る。そしてその液中にCa(OH)2の飽和液を供給するとと
もに通電することにより、カソード電流によって鋼表面
にはCaイオンとMgイオンが引き寄せられ、pHが８〜10に
達し、Caイオン濃度が38ppmとなり、さらに液中に溶存
しているHCO3イオンが引き寄せられ、式１に示す反応に
よって皮膜が鋼表面に析出してくる。本発明に従った試
験No.2で得られた皮膜は厚さ100〜150μｍでしかも耐久
性に優れたものであった。
【００１０】
【式１】
【００１１】なお、上記式１の反応は海水環境中ではCa
イオン濃度400ppm、Mgイオン濃度1200ppmとイオン濃度
が高いため、通電により数週間で形成される。しかし、
淡水環境中では水中にCa、Mg成分が少ないため（Ca:20p
pm、Mg:5.0ppm)、通電によって早期に皮膜形成させるに
は１〜２年間という長期間を要する。従って、淡水環境
中で良質の皮膜を短期間に形成させるためには、Ca硬度
とＭアルカリ度を高めることが重要であり、そのために
はMg(OH)2やCa(OH)2等の添加物を混入させることによっ
て水質を改善させることができる。
【００１２】上記実験室試験およびその結果である表１
に示した結果より、鋼の電位は約−900mVが適当であ
り、この時の電流密度は0.4A/m2以上である。また皮膜
形成時の液pHは８〜9.5程度であった。そして、Mg(OH)2
量は増加するにつれて分極抵抗値が上昇し、良質の皮膜
が得られることが分かった。皮膜形成後は、電極部は撤
去されるが、この皮膜の優れた耐久性によって内壁の防
食が長期にわたって可能になり、また循環水のpHを調整
することによってさらに皮膜の耐久性を増加させること
が可能になる。
【００１３】
【実施例】ビルの冷温用として熱交換器まで設備されて
いる蓄熱循環水配管の防食を本発明に従って試験した。
配管は管径500φで蓄熱槽間と常時循環状態にある。こ
の配管７に100ｍ範囲を限定して図２に示す電極装置を
取り付けた。電極装置は配管内に配設された電極部８、
同じく配管内に設置された照合電極９が配管に設けられ
た電極引出し金具10で配管外に導かれ、配線11で直流電
源装置12に結線され、この直流電源装置12には管理装置
13が設けられている。
【００１４】電極引出し金具10は図３に示すようにグラ
ンド構造をなし、電極部８をなすケーブル電極が水密と
絶縁を兼ねて外部へ引出せるようにグランド方式に締め
付け固定されている。また、電極部８は図４に示すよう
にポリエチレンケーブル（外径10.8mmφ）の外側にPt-T
aメッシュ状電極を巻き付け、電極部は1.0ｍ範囲毎にケ
ーブル内の銅芯にPt-Taメッシュとを結線させ、結線部
はエポキシ樹脂を充填し硬化させ。さらに1.0ｍ間隔に
配管内面と接触しないようPVC製フランジリング14を固
定させ、全長約100ｍものとして一本の電極部を構成さ
せた。なお、照合電極９は配管内の適当なPVC製フラン
ジリング14に取り付けることが好ましい。
【００１５】直流電源装置12は定電位自動制御方式とし
て出力容量60Ｖ×100Ａとした。配管への初期電流とし
て0.5Ａ／ｍ2として約90Ａの電流を流した。その各項目
を下記に示す。
型式 定電位自動制御方式 自冷型
入力 200Ｖ 10ＫＶＡ
出力 60Ｖ×100Ａ×１cct
重量 150kg
【００１６】一方の準備として、通電前に蓄熱槽内の循
環水のＣａ，Ｍｇイオン濃度、pH、アルカリ度を測定す
るものとし、前工程としてMg(OH)2の粉末を200ppm 添加
し、CO2ガスを循環水pHが約6.0となるまで供給した。次
いで、Ca(OH)2飽和液を添加し、液pHが8.5、Caイオン濃
度が40ppmになるよう事前に液の調整を行った。通電は
所定の電流値を直流電源装置より連続し、定電位自動制
御方式であるため、−900mVに一定させた。途中の皮膜
形成の確認には皮膜管理装置にて一時的に電源をoffに
して電位の減衰特性より皮膜成分測定した。また、分極
抵抗値は週２回の割合で測定し、値が400Ωcm2に達した
時点で良好な皮膜が形成されているものと判断した。そ
の結果、約２週間程度で良好な防食皮膜が管内面全体に
厚く形成されており、耐久性も十分なものであった。な
お、防食皮膜の形成が終了した後、管内から電極部をフ
ランジリングとメッシュ電極とを電極引出し金具から引
出し、通常の装置実働運転を行った。
【００１７】
【発明の効果】以上のような本発明によれば、外部から
強制的に防食すべき管もしくはタンク部にカソード電流
を供給し、かつ循環水中にMg(OH)2およびCa(OH)2を添加
して水中のCaイオン、Mgイオンを管内面もしくはタンク
内面に付着させるものであり、配管もしくはタンク部の
建設時あるいは運転途中の休止時に管内面もしくはタン
ク部内面に良好で耐久性のある防食皮膜を形成すること
ができ、一旦皮膜が形成されればその後のメンテナンス
あるいは水質管理等の運用が極めて簡便となる。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for circulating so-called fresh water through a pipe or a tank, such as an open regenerative air conditioner, to prevent corrosion of the pipe or the tank inside. It relates to a method for forming a film. 2. Description of the Related Art Normally, in various devices such as open regenerative air-conditioning equipment for circulating so-called fresh water through pipes or tank inner surfaces, the pipes or tanks are always in an underwater environment. Rust prevention measures are taken, but macrocell corrosion at damaged coatings due to aging,
Corrosion on the inner surface of the piping due to the propagation of microorganisms in the liquid is 0.3%.
It has reached ~ 0.4mm / y. As a maintenance, it is common to remove the rust from the pipe or the tank inner surface and repaint it. However, painting is impossible because water does not actually escape.
In addition, a method of circulating a mixture of carbon dioxide and Ca (OH) 2 to form a calcium carbonate film naturally has been used to improve water quality. Even in these methods, when rust or dirt is adhered to the pipe or the inner surface of the tank, a sufficient adhesion effect cannot be obtained, resulting in a non-uniform film state. In addition, these methods always require adjustment of the pH of water quality and the like, and maintenance is important, and they are not necessarily economical. In addition, water in Japan has low Ca hardness as soft water, and it is difficult to form a calcium carbonate film on pipes or tanks. These are Ca hardness and water pH,
This is because the saturation index of CaCO 3 obtained from M alkalinity becomes negative. Therefore, to make the calcium carbonate film adhere evenly to the pipe or tank inner surface, artificial hardness water to increase the Ca hardness and M alkalinity by improving the water quality of the circulating water has been studied, and fine pH and water quality components have been studied. This is an important issue to be considered, including the operation and management of the system. SUMMARY OF THE INVENTION The present invention relates to a piping system in which a so-called fresh water is circulated in a piping or a tank inner surface, such as an open regenerative air conditioner, in which a stable anti-corrosion film has conventionally been difficult to form. Another object of the present invention is to provide a method capable of easily forming a uniform and good anticorrosion film on the inner surface of a tank. Under these problems, the present inventor
As a result of intensive studies, Ca ions and Mg ions were supplied to the water, and at the same time, a direct current (cathode current) was supplied to the pipe or tank inner surface from an external DC power supply via a pipe line and the electrode section arranged in the tank. ), It was found that a mixed anticorrosive film of CaCO 3 and Mg (OH) 2 could be formed on the pipe or the inner wall of the tank. The present invention is based on this finding. [0004] That is, the present invention provides an electrode portion of a predetermined length that is detachably attached to an arbitrary location in a pipe or a tank, and then the electrode section is preliminarily added to fresh water circulated in the pipe or the tank. After mixing Mg (OH) 2 and CO 2 gas to form bicarbonate ions in the circulating water, Ca (O
H) A saturated solution of 2 was added to adjust the pH to 8 to 10, and a DC current was supplied from an external DC power supply to the electrode section, so that CaCO 3 , Mg was added to the pipe or tank inner wall. The present invention is characterized in that a mixed anticorrosive film of (OH) 2 system is formed, thereby achieving the above object. DETAILED DESCRIPTION OF THE INVENTION In the present invention, a laboratory test as shown in FIG. 1 was prepared in order to confirm the action and to set each process condition. In this test machine, a compound of Ca (OH) 2 and Mg (OH) 2 was added at a different ratio to 20 liters of tap water as a circulating liquid, and a series of combinations of various conditions with different currents and currents. Was tested. In FIG. 1, a cell 2 is placed in the middle of a circulating fluid 1, a test piece 3 (75 × 100 × 1.0 mm) and a Pt-Ti electrode as a current-carrying electrode 4 are placed therein, and a reference electrode 5 provided separately.
The test piece 3 was turned on by the potentiostat 6 so that the potential of the test piece 3 became -900 mV (SCE). The energization time is 1,
Divided into two or three weeks, the current flow during the period, polarization resistance, pH
Was recorded, and the test piece 3 was pulled up within each period to observe the surface. Table 1 shows the results. [Table 1] [0008] The additive components in Table 1 indicate the amount of additives or ions added to the circulating water. Further, the pH change is a pH value when the anticorrosion film adheres. From Table 1, it can be seen that the data of Test No. 2 according to the present invention formed the best film. That is, Mg (OH) 2 is added to the circulating water, and CO 2 gas is added until the pH of the liquid becomes about 6. The supply of the CO 2 gas is for generating bicarbonate ions in the liquid. With the increase of the bicarbonate ions, the M alkalinity increases,
In the next step, the formation of a film by the supply of a saturated solution of Ca (OH) 2 is promoted, and at the same time, the formation of a good film is promoted. Therefore, it is necessary to supply the CO 2 gas so that the amount of bicarbonate ion in the liquid is sufficient to contribute to the reaction represented by the formula (a) of Formula 1 and the alkalinity is sufficiently M. As a rough guide, supply the solution so that the pH of the solution is about 6. Then, by supplying a saturated solution of Ca (OH) 2 into the solution and applying an electric current, Ca ions and Mg ions are attracted to the steel surface by the cathodic current, the pH reaches 8 to 10, and the Ca ion concentration is increased. The concentration becomes 38 ppm, and the HCO 3 ions dissolved in the liquid are further attracted, and a film is deposited on the steel surface by the reaction shown in Formula 1. The coating obtained in Test No. 2 according to the present invention had a thickness of 100 to 150 μm and was excellent in durability. [Equation 1] [0011] The reaction of the above formula 1 is carried out in a seawater environment.
Since the ion concentration is as high as 400 ppm and the Mg ion concentration is 1200 ppm, it is formed in a few weeks by energization. But,
In a freshwater environment, there are few Ca and Mg components in the water (Ca: 20p
(pm, Mg: 5.0 ppm), it takes a long period of 1 to 2 years to form a film at an early stage by energization. Therefore, it is important to increase Ca hardness and M alkalinity in order to form a good quality film in a freshwater environment in a short period of time, and for that purpose, Mg (OH) 2 or Ca (OH) 2 must be added. The quality of water can be improved by mixing the substances. The above laboratory tests and the results are shown in Table 1.
According to the results shown in the above, the potential of the steel is suitably about -900 mV, and the current density at this time is 0.4 A / m 2 or more. The pH of the solution at the time of film formation was about 8 to 9.5. And Mg (OH) 2
It was found that the polarization resistance increased as the amount increased, and that a good quality film was obtained. After the film is formed, the electrode part is removed, but the excellent durability of this film enables corrosion protection of the inner wall for a long time, and the durability of the film is further increased by adjusting the pH of the circulating water. Becomes possible. EXAMPLE The corrosion protection of a regenerative circulating water line, which is equipped with a heat exchanger for cooling and heating a building, was tested in accordance with the present invention.
The pipe has a diameter of 500φ and is constantly circulating between the heat storage tanks. The electrode device shown in FIG. The electrode device is an electrode unit 8 disposed in the pipe,
The reference electrode 9 also installed in the pipe is led out of the pipe by an electrode lead-out fitting 10 provided in the pipe, and connected to a DC power supply 12 by a wiring 11.
13 are provided. The electrode lead-out fitting 10 has a ground structure as shown in FIG. 3, and is fixed in a grounding manner so that the cable electrode forming the electrode section 8 can be pulled out to the outside while providing watertightness and insulation. The electrode section 8 is made of Pt-T on the outside of a polyethylene cable (outer diameter 10.8 mmφ) as shown in FIG.
aWound a mesh electrode, connect the Pt-Ta mesh to the copper core in the cable every 1.0m in the electrode part, fill the connection part with epoxy resin and cure. Further, a flange ring 14 made of PVC was fixed at an interval of 1.0 m so as not to come into contact with the inner surface of the pipe, and one electrode portion was formed having a total length of about 100 m. The reference electrode 9 is preferably attached to an appropriate PVC flange ring 14 in the pipe. The DC power supply 12 has an output capacity of 60 V × 100 A as a constant potential automatic control system. A current of about 90 A was passed at 0.5 A / m 2 as an initial current to the pipe. Each item is shown below. Model Constant potential automatic control method Self-cooling type input 200V 10KVA output 60V × 100A × 1cct Weight 150kg As one preparation, measure Ca, Mg ion concentration, pH and alkalinity of circulating water in the heat storage tank before energization. As a previous step, 200 ppm of Mg (OH) 2 powder was added, and CO 2 gas was supplied until the pH of the circulating water reached about 6.0. Next, a Ca (OH) 2 saturated solution was added, and the solution was adjusted in advance so that the solution pH was 8.5 and the Ca ion concentration was 40 ppm. Energization was continued at a predetermined current value from the DC power supply device, and was kept constant at -900 mV because of the constant potential automatic control system. In order to confirm the formation of the film on the way, the power was temporarily turned off by the film management device, and the film component was measured from the decay characteristic of the potential. The polarization resistance was measured twice a week, and when the value reached 400 Ωcm 2 , it was judged that a good film was formed. As a result, in about two weeks, a good anticorrosion film was formed thickly on the entire inner surface of the tube, and the durability was sufficient. After the formation of the anticorrosion film was completed, the electrode portion was pulled out of the tube with the flange ring and the mesh electrode from the electrode lead-out fitting, and a normal operation of the apparatus was performed. According to the present invention as described above, a cathodic current is externally supplied to a pipe or a tank to be forcibly protected, and Mg (OH) 2 and Ca (OH) are supplied to the circulating water. 2 ) Adds Ca ions and Mg ions in water to adhere to the inner surface of the pipe or tank, and provides good durability on the inner surface of the pipe or tank during construction of pipes or tanks or at rest during operation. It is possible to form a corrosion-resistant film having a certain quality, and once the film is formed, subsequent operations such as maintenance or water quality control become extremely simple.
【図面の簡単な説明】
【図１】本発明方法を実施する場合の実験室試験の概略
配管配置図である。
【図２】本発明方法を実機に適用した場合の装置の概略
説明図である。
【図３】電極引出し金具を示す断面説明図である。
【図４】電極部の構成の概略を示す説明図である。
【符号の説明】
１ 循環液
２ セル
３ テストピース
４ 通電電極
５ 照合電極
６ ポテンショスタット
７ 配管
８ 電極部
９ 照合電極
10 電極引出し金具
11 配線
12 直流電源装置
13 管理装置
14 フランジリングBRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic piping arrangement diagram of a laboratory test when carrying out the method of the present invention. FIG. 2 is a schematic explanatory view of an apparatus when the method of the present invention is applied to an actual machine. FIG. 3 is an explanatory sectional view showing an electrode lead-out fitting. FIG. 4 is an explanatory view schematically showing a configuration of an electrode unit. [Description of Signs] 1 Circulating fluid 2 Cell 3 Test piece 4 Energized electrode 5 Reference electrode 6 Potentiostat 7 Piping 8 Electrode section 9 Reference electrode 10 Electrode extraction fitting 11 Wiring 12 DC power supply 13 Management device 14 Flange ring
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭53−60879（ＪＰ，Ａ) 特開 平１−176083（ＪＰ，Ａ) 特開 平２−194893（ＪＰ，Ａ) 特開 平５−293476（ＪＰ，Ａ) 特開 平９−316672（ＪＰ，Ａ) 特開 平６−254572（ＪＰ，Ａ) 特開 平８−53782（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) F16L 57/00 - 58/18 B65D 90/22 C23F 15/00 F28F 19/02 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-53-60879 (JP, A) JP-A-1-1766083 (JP, A) JP-A-2-194893 (JP, A) JP-A-5-1985 293476 (JP, A) JP-A-9-316672 (JP, A) JP-A-6-254572 (JP, A) JP-A-8-53782 (JP, A) (58) Fields investigated (Int. 7 , DB name) F16L 57/00-58/18 B65D 90/22 C23F 15/00 F28F 19/02
Claims (1)
定長さの電極部を取外し可能に取付け、その後配管もし
くはタンク内に循環させる淡水にあらかじめMg(OH)2お
よびCO2ガスを混入させて循環水中に重炭酸イオンを形
成せしめた後、Ca(OH)2の飽和液を添加してpHを８〜10
に調整するとともに、外部に設けた直流電源装置から前
記電極部に直流電流を供給することにより、前記配管も
しくはタンク内壁にCaCO3,Mg(OH)2系の混合した防食皮
膜を形成させることを特徴とする配管もしくはタンク内
面の防食皮膜形成方法。(57) [Claims] [Claim 1] An electrode part of a predetermined length is detachably attached to an arbitrary place in a pipe or a tank, and then Mg (OH) is added to fresh water to be circulated in the pipe or the tank in advance. 2 and CO 2 gas to form bicarbonate ions in the circulating water, and then add a saturated solution of Ca (OH) 2 to adjust the pH to 8-10.
By supplying a direct current to the electrode part from a DC power supply device provided outside, a CaCO 3 , Mg (OH) 2 mixed anticorrosive film is formed on the pipe or the inner wall of the tank. Characteristic method of forming an anticorrosion film on the inner surface of piping or tank
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29347597A JP3429650B2 (en) | 1997-10-09 | 1997-10-09 | Method of forming anti-corrosion film on piping or tank inner surface |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29347597A JP3429650B2 (en) | 1997-10-09 | 1997-10-09 | Method of forming anti-corrosion film on piping or tank inner surface |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11153287A JPH11153287A (en) | 1999-06-08 |
| JP3429650B2 true JP3429650B2 (en) | 2003-07-22 |
Family
ID=17795228
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29347597A Expired - Fee Related JP3429650B2 (en) | 1997-10-09 | 1997-10-09 | Method of forming anti-corrosion film on piping or tank inner surface |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3429650B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011024758A1 (en) * | 2009-08-24 | 2011-03-03 | 菊水化学工業株式会社 | Anti-corrosive coating |
-
1997
- 1997-10-09 JP JP29347597A patent/JP3429650B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH11153287A (en) | 1999-06-08 |
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