JPS6312245Y2 - - Google Patents
Info
- Publication number
- JPS6312245Y2 JPS6312245Y2 JP1982002119U JP211982U JPS6312245Y2 JP S6312245 Y2 JPS6312245 Y2 JP S6312245Y2 JP 1982002119 U JP1982002119 U JP 1982002119U JP 211982 U JP211982 U JP 211982U JP S6312245 Y2 JPS6312245 Y2 JP S6312245Y2
- Authority
- JP
- Japan
- Prior art keywords
- stud bolt
- protection tube
- bolt protection
- stud
- prevention device
- 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
Links
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 26
- 238000005536 corrosion prevention Methods 0.000 claims description 15
- 229910052742 iron Inorganic materials 0.000 claims description 13
- 239000007769 metal material Substances 0.000 claims description 10
- 230000001012 protector Effects 0.000 claims 1
- 239000000463 material Substances 0.000 description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 14
- 230000007797 corrosion Effects 0.000 description 12
- 238000005260 corrosion Methods 0.000 description 12
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000007689 inspection Methods 0.000 description 4
- 239000003758 nuclear fuel Substances 0.000 description 4
- 229910052725 zinc Inorganic materials 0.000 description 4
- 239000011701 zinc Substances 0.000 description 4
- 230000000737 periodic effect Effects 0.000 description 3
- 239000008151 electrolyte solution Substances 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- -1 aluminum or zinc Chemical compound 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
Landscapes
- Protection Of Pipes Against Damage, Friction, And Corrosion (AREA)
- Prevention Of Electric Corrosion (AREA)
Description
【考案の詳細な説明】
本考案は，原子炉圧力容器の上蓋締め付け用ス
タツドボルトに被せられるスタツドボルト保護筒
に係り，特にスタツドボルトの腐食を防止する装
置を備えたスタツドボルト保護筒に関する。[Detailed Description of the Invention] The present invention relates to a stud bolt protection case that is placed over a stud bolt for tightening the upper lid of a nuclear reactor pressure vessel, and more particularly to a stud bolt protection case that is equipped with a device for preventing corrosion of the stud bolt.
原子炉圧力容器の上蓋は，核燃料交換および炉
内点検を行う定期点検の度に，開閉が繰り返され
る。その開閉時，この上蓋の接触によつて，当該
原子炉圧力容器に螺合された該上蓋締め付け用の
スタツドボルトが損傷することを防止するために
円筒形のスタツドボルト保護筒が該スタツドボル
トに被せられる。すなわち，定期検査における核
燃料交換の際は，まずこのスタツドボルト保護筒
がスタツドボルトに被せられた状態で，前記上蓋
が取り外され，その後該スタツドボルト保護筒も
外される。次に，放射線の量が低い水中で核燃料
交換の作業が行われるため，スタツドボルトは水
没させられる。そして，核燃料交換が終了する
と，水位は下げられ，スタツドボルトは大気にさ
らされる乾燥状態に戻り，その後再びスタツドボ
ルト保護筒が該スタツドボルトに被せられて，上
蓋が閉じられる。 The reactor pressure vessel top cover is repeatedly opened and closed during regular inspections to replace nuclear fuel and inspect the inside of the reactor. In order to prevent damage to the stud bolts screwed into the reactor pressure vessel for tightening the upper lid due to contact with the upper lid when the upper lid is opened and closed, a cylindrical stud bolt protection cylinder is attached to the stud bolt. covered. That is, when nuclear fuel is replaced during a periodic inspection, the stud bolt protection tube is placed over the stud bolt, and the upper cover is removed, and then the stud bolt protection tube is also removed. Next, the stud bolts are submerged as nuclear fuel exchange work takes place underwater, where radiation levels are low. When the nuclear fuel exchange is completed, the water level is lowered and the stud bolt returns to a dry state where it is exposed to the atmosphere.The stud bolt protection tube is then placed over the stud bolt again and the top cover is closed.
このように鉄材で作られたスタツドボルトは，
定期検査の度に水没させられる状態および大気に
されされる状態が繰り返されるので，ねじ部を含
めた該スタツドボルトの外表面が腐食してしまう
ことが起こる。この腐食が進行すると，上蓋をし
つかりと締め付けることができなくなり，当該原
子炉圧力容器の安全の確保のために該スタツドボ
ルトを新製品と取り換えることも必要になつてく
る。しかしながら，従来は該スタツドボルトの腐
食を防止する手段は何ら施されておらず，また，
スタツドボルト保護筒にも該スタツドボルトの腐
食防止機能を備えたものはない。すなわち，前述
のようにスタツドボルト保護筒が外された状態で
鉄材のスタツドボルトは水没させられるものであ
り，仮にスタツドボルト保護筒を被せたまま水没
させても，水は該スタツドボルト保護筒内に流入
してしまうので，このスタツドボルト保護筒はス
タツドボルトの腐食を防止することはできない。 Stud bolts made of iron like this are
Since the stud bolt is repeatedly submerged in water and exposed to the atmosphere during periodic inspections, the outer surface of the stud bolt, including the threaded portion, may corrode. As this corrosion progresses, it becomes impossible to firmly tighten the top cover, and it becomes necessary to replace the stud bolt with a new product to ensure the safety of the reactor pressure vessel. However, conventionally, no means have been taken to prevent corrosion of the stud bolts, and
There is no stud bolt protection cylinder that has a function to prevent corrosion of the stud bolt. In other words, as mentioned above, the steel stud bolt is submerged in water with the stud bolt protection tube removed, and even if the stud bolt is submerged in water with the stud bolt protection tube still on, water will still drain into the stud bolt protection tube. This stud bolt protection tube cannot prevent corrosion of the stud bolts.
本考案は，このような従来の原子炉圧力容器の
上蓋締め付け用のスタツドボルトおよびスタツド
ボルト保護筒の実情に鑑みてなされたもので，そ
の目的はスタツドボルトの腐食を防止する腐食防
止装置を備えたスタツドボルト保護筒を提供する
にある。 The present invention was developed in view of the current situation of stud bolts and stud bolt protection tubes for tightening the top cover of reactor pressure vessels, and its purpose is to provide a corrosion prevention device to prevent corrosion of the stud bolts. To provide a stud bolt protection tube.
すなわち，本考案はスタツドボルト保護筒をス
タツドボルトに被せた状態において，該スタツド
ボルト保護筒の内面，開口部先端の少なくとも一
方に，アルミ，亜鉛等の鉄より電位の低い金属材
が設けてあり，かつ該金属材が前記スタツドボル
トに接触していることを特徴とする腐食防止装置
が該スタツドボルト保護筒に設けてあるので，こ
のスタツドボルト保護筒を被せたままスタツドボ
ルトを水没させると，該スタツドボルト，前記金
属材および水によつてガルヴアーニ電池が形成さ
れて，それによりスタツドボルトの腐食が防止で
きるというものである。 That is, in the present invention, when the stud bolt protection tube is placed over the stud bolt, at least one of the inner surface and the tip of the opening of the stud bolt protection tube is provided with a metal material having a lower potential than iron, such as aluminum or zinc. Since a corrosion prevention device characterized in that the metal material is in contact with the stud bolt is provided on the stud bolt protection tube, if the stud bolt is submerged in water with the stud bolt protection tube covered, The stud bolt, the metal material, and water form a galvanic cell, thereby preventing corrosion of the stud bolt.
以下本考案の腐食防止装置を備えたスタツドボ
ルト保護筒を図面に基づいてより詳細に説明す
る。第１図ａはスタツドボルトに被せられた，本
考案の腐食防止装置を備えたスタツドボルト保護
筒の縦断面図，第１図ｂは第１図ａのＡ−Ａ部分
の断面図であり，これ等第１図ａ，ｂは本考案の
第１の実施例を示す。図において，５は原子炉圧
力容器の上蓋，４は当該原子炉圧力容器のフラン
ジ，３はフランジ４に螺合され，上蓋５を締め付
けるためのスタツドボルト，２は上蓋５の開閉
時，該上蓋５の接触によるスタツドボルト３の損
傷を防止するために該スタツドボルト３に被せら
れるスタツドボルト保護筒で，図示のようにスタ
ツドボルト３の上端のねじ部と噛み合つて固定す
るようになつている。１はスタツドボルト３の腐
食を防止するための腐食防止装置，すなわち，ア
ルミ，亜鉛等の鉄より電位の低い金属で作つてあ
る金属材，すなわち接触材で，スタツドボルト保
護筒２の内面，すなわち該スタツドボルト保護筒
２の内壁とスタツドボルト３との間に介在して，
該スタツドボルト３に接触している。なお，これ
ら第１図ａ，ｂに示す第１の実施例の接触材１は
スタツドボルト３の外周面に沿うような円筒面を
有する数個の板状の断片に分割してある。そし
て，それぞれの断片をスタツドボルト３を取り囲
むように配置し，スタツドボルト保護筒２を挿入
することによつて取り付けてある。また，フラン
ジ４とスタツドボルト３とのねじ込み隙間８は，
定期点検における排出後の水はけが悪いので、接
触材１はスタツドボルト保護筒２の開口部先端に
突出して設けてあり，該接触材１の下端が該ねじ
込み隙間８にまで十分接触するようになつてい
る。このように構成してあるので，スタツドボル
ト３およびスタツドボルト保護筒２を水没させる
と，スタツドボルト３，接触材１が電極として，
また水が電解溶液としてガルヴアーニ電池を形成
し，それによりスタツドボルト３の腐食を効果的
に防止することができる。その理由を以下に記述
する。すなわち，鉄材であるスタツドボルト３の
みが水中にある場合は，例えばその水中における
不純物の付着によつて，該鉄材に表面上の状態の
相違が生ずる。その相違により，部分的に電位差
を生じ，（＋），（−）の電極が該鉄材上に発生す
る。そうなると，前記（−）極の箇所で腐食が進
行することになる。しかしながら，この第１の実
施例におけるようにアルミ，亜鉛等の鉄より電位
の低いに金属で作つた接触材１が，鉄材であるス
タツドボルト３に接触して形成されるガルヴアー
ニ電池にあつては，鉄材より低電位の接触材１が
必ず（−）極となり、鉄材であるスタツドボルト
３の腐食が防止されるわけである。 Hereinafter, the stud bolt protection tube equipped with the corrosion prevention device of the present invention will be explained in more detail based on the drawings. FIG. 1a is a longitudinal sectional view of a stud bolt protection tube equipped with the corrosion prevention device of the present invention, which is placed over a stud bolt, and FIG. 1b is a sectional view taken along the line A-A in FIG. 1a. 1a and 1b show a first embodiment of the present invention. In the figure, 5 is the upper cover of the reactor pressure vessel, 4 is the flange of the reactor pressure vessel, 3 is a stud bolt that is screwed onto the flange 4 and used to tighten the upper cover 5, and 2 is the stud bolt that is used to tighten the upper cover 5 when the upper cover 5 is opened or closed. This is a stud bolt protection tube that is placed over the stud bolt 3 to prevent damage to the stud bolt 3 due to contact with the stud bolt 3, and is designed to be fixed by engaging with the threaded portion at the upper end of the stud bolt 3 as shown in the figure. . Reference numeral 1 denotes a corrosion prevention device for preventing corrosion of the stud bolt 3, that is, a metal material such as aluminum or zinc that has a lower potential than iron, that is, a contact material. Interposed between the inner wall of the stud bolt protection cylinder 2 and the stud bolt 3,
It is in contact with the stud bolt 3. The contact material 1 of the first embodiment shown in FIGS. 1a and 1b is divided into several plate-shaped pieces each having a cylindrical surface along the outer peripheral surface of the stud bolt 3. As shown in FIG. The respective pieces are arranged to surround the stud bolt 3, and are attached by inserting the stud bolt protection tube 2. In addition, the screw clearance 8 between the flange 4 and the stud bolt 3 is
Since water drainage after discharge during periodic inspection is poor, the contact material 1 is provided protruding from the opening tip of the stud bolt protection tube 2, so that the lower end of the contact material 1 comes into sufficient contact with the screw-in gap 8. ing. With this structure, when the stud bolt 3 and the stud bolt protection tube 2 are submerged in water, the stud bolt 3 and the contact material 1 act as electrodes.
In addition, water forms a galvanic cell as an electrolytic solution, thereby effectively preventing corrosion of the stud bolt 3. The reason is described below. That is, when only the stud bolt 3, which is an iron material, is in water, a difference in the surface condition of the iron material occurs due to adhesion of impurities in the water, for example. Due to this difference, a potential difference is generated locally, and (+) and (-) electrodes are generated on the iron material. If this happens, corrosion will progress at the (-) pole. However, in the case of a Galvanic battery in which the contact material 1 made of a metal such as aluminum or zinc having a lower potential than iron comes into contact with the stud bolt 3 made of iron as in the first embodiment, , the contact material 1, which has a lower potential than the iron material, always becomes the (-) pole, and corrosion of the stud bolt 3, which is made of iron material, is prevented.
なお，スタツドボルト保護筒２も，接触材１と
同様に，アルミ，亜鉛等の鉄より電位の低い金属
材で作ることにより，上記の効果をより高めるこ
とができる。 Note that, like the contact material 1, the stud bolt protection tube 2 can also be made of a metal material having a lower potential than iron, such as aluminum or zinc, to further enhance the above effect.
第２図，第３図はそれぞれ本考案の第２，第３
の実施例を示す図である。第２図に示す第２の実
施例は，接触材６が蛇腹式に形成してあり、第３
図に示す第３の実施例は，接触材７がワイヤブラ
シ構造になつている。このような構成の第２，第
３の実施例にあつては，ガルヴアーニ電池の電解
質溶液である水に対する接触表面積が，第１の実
施例における板状の接触材１（第１図）よりも大
きいので，スタツドボルト３の腐食防止効果がよ
り大きい。 Figures 2 and 3 are the second and third versions of the present invention, respectively.
It is a figure showing an example of. In the second embodiment shown in FIG. 2, the contact member 6 is formed in a bellows type, and the third
In the third embodiment shown in the figure, the contact member 7 has a wire brush structure. In the second and third embodiments having such a configuration, the contact surface area of the Galvanic battery with water, which is an electrolyte solution, is larger than that of the plate-shaped contact material 1 (FIG. 1) in the first embodiment. Since it is large, the corrosion prevention effect of the stud bolt 3 is greater.
第４図ａ〜ｃは本考案の第４の実施例を示す図
である。この第４の実施例は，円筒面を有する数
個に分割された板状の接触材１′がスタツドボル
ト保護筒２に取り付けてある。その取り付け構造
は図示のように，接触材１′に固定したピン１０
がスタツドボルト保護筒２に形成した縦長の溝９
に若干の遊びを有して嵌合することにより，摺動
自在に取り付けてある。このような構造になつて
いるので，図から明らかなようにスタツドボルト
保護筒２をスタツドボルト３に挿入し，矢印Ｂ方
向へ挿入を進めると，接触材１′の下端がフラン
ジ４に当たり，さらに挿入すると接触材１′がス
タツドボルト３の表面へ接触するようになつてい
る。 Figures 4a to 4c are diagrams showing a fourth embodiment of the present invention. In this fourth embodiment, a plate-shaped contact member 1' having a cylindrical surface and divided into several pieces is attached to a stud bolt protection cylinder 2. As shown in the figure, the mounting structure consists of a pin 10 fixed to the contact material 1'.
The vertical groove 9 formed in the stud bolt protection tube 2
It is slidably attached by fitting with some play. With this structure, as is clear from the figure, when the stud bolt protection tube 2 is inserted into the stud bolt 3 and the insertion is advanced in the direction of arrow B, the lower end of the contact material 1' hits the flange 4, and further When inserted, the contact member 1' comes into contact with the surface of the stud bolt 3.
上記の第２〜第４の実施例も第１の実施例と同
様の効果を奏するのは明らかである。また，本考
案の腐食防止装置を備えたスタツドボルト保護筒
における，上記接触材の形状，および該接触材の
スタツドボルト保護筒への取り付け構造は，これ
らの実施例に限定されないのは言うまでもない。 It is clear that the second to fourth embodiments described above also have the same effects as the first embodiment. It goes without saying that the shape of the contact material and the structure for attaching the contact material to the stud bolt protection tube in the stud bolt protection tube equipped with the corrosion prevention device of the present invention are not limited to these embodiments.
上記のように本考案の腐食防止装置を備えたス
タツドボルト保護筒は，スタツドボルトを水没さ
せる際，該スタツドボルトに当該スタツドボルト
保護筒を被せることによつて，ガルヴアーニ電池
を形成し，それにより該スタツドボルトの腐食を
防止することができる効果がある。 As mentioned above, the stud bolt protection tube equipped with the corrosion prevention device of the present invention forms a galvanic battery by covering the stud bolt with the stud bolt protection tube when the stud bolt is submerged in water. This has the effect of preventing corrosion of the stud bolt.
第１図ａは本考案の第１の実施例の，腐食防止
装置を備えたスタツドボルト保護筒の縦断面図，
第１図ｂは第１図ａのＡ−Ａ部分の断面図，第２
図，第３図はそれぞれ本考案の第２，第３の実施
例の，腐食防止装置を備えたスタツドボルト保護
筒の部分縦断面図，第４図ａ，ｂはそれぞれ本考
案の第４の実施例の，腐食防止装置を備えたスタ
ツドボルト保護筒の部分縦断面図，第４図ｃは第
４図ｂの正面図である。
１，１′，６，７……接触材、２……スタツド
ボルト保護筒、３……スタツドボルト、４……フ
ランジ、５……上蓋、８……ねじ込み隙間、９…
…溝、１０……ピン。
FIG. 1a is a longitudinal cross-sectional view of a stud bolt protection tube equipped with a corrosion prevention device according to the first embodiment of the present invention;
Figure 1b is a sectional view of the A-A section in Figure 1a,
3 and 3 are partial longitudinal sectional views of stud bolt protection tubes equipped with a corrosion prevention device according to the second and third embodiments of the present invention, respectively, and FIGS. 4a and 4b are respectively the fourth embodiment of the present invention. FIG. 4c is a partial longitudinal cross-sectional view of a stud bolt protection tube equipped with a corrosion prevention device according to an embodiment, and FIG. 4c is a front view of FIG. 4b. 1, 1', 6, 7...Contact material, 2...Stud bolt protection cylinder, 3...Stud bolt, 4...Flange, 5...Top cover, 8...Screw clearance, 9...
...Groove, 10...pin.
Claims (1)
ボルトに被せられるスタツドボルト保護筒にお
いて，該スタツドボルト保護筒をスタツドボル
トに被せた状態で，該スタツドボルト保護筒の
内面，開口部先端の少なくとも一方に，鉄より
電位の低い金属材が設けてあり，かつ該金属材
が前記スタツドボルトに接触していることを特
徴とする腐食防止装置を備えたスタツドボルト
保護筒。 (2) 前記スタツドボルト保護筒が，鉄より電位の
低い金属材で作つてあることを特徴とする実用
新案登録請求の範囲第１項記載の腐食防止装置
を備えたスタツドボルト保護筒。 (3) 前記金属材が蛇腹式に形成してあることを特
徴とする実用新案登録請求の範囲第１項または
第２項記載の腐食防止装置を備えたスタツドボ
ルト保護筒。 (4) 前記金属材がワイヤブラシ構造にしてあるこ
とを特徴とする実用新案登録請求の範囲第１項
または第２項記載の腐食防止装置を備えたスタ
ツドボルト保護筒。[Scope of Claim for Utility Model Registration] (1) In a stud bolt protection tube that is placed over a stud bolt for tightening the upper lid of a reactor pressure vessel, the stud bolt protection tube is covered with the stud bolt. A stud bolt protector equipped with a corrosion prevention device, characterized in that a metal material having a lower potential than iron is provided on at least one of the inner surface and the tip of the opening, and the metal material is in contact with the stud bolt. Tube. (2) The stud bolt protection tube equipped with a corrosion prevention device according to claim 1, wherein the stud bolt protection tube is made of a metal material having a lower potential than iron. (3) A stud bolt protection tube equipped with a corrosion prevention device according to claim 1 or 2, wherein the metal material is formed into a bellows type. (4) A stud bolt protection tube equipped with a corrosion prevention device according to claim 1 or 2, wherein the metal material has a wire brush structure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1982002119U JPS58106609U (en) | 1982-01-13 | 1982-01-13 | Stud bolt protection tube with corrosion protection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1982002119U JPS58106609U (en) | 1982-01-13 | 1982-01-13 | Stud bolt protection tube with corrosion protection device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58106609U JPS58106609U (en) | 1983-07-20 |
| JPS6312245Y2 true JPS6312245Y2 (en) | 1988-04-08 |
Family
ID=30015102
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1982002119U Granted JPS58106609U (en) | 1982-01-13 | 1982-01-13 | Stud bolt protection tube with corrosion protection device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58106609U (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4955635B2 (en) * | 2008-09-26 | 2012-06-20 | 株式会社Ｉｈｉインフラシステム | Rust prevention cap integrated bolt temporary fixing nut |
-
1982
- 1982-01-13 JP JP1982002119U patent/JPS58106609U/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58106609U (en) | 1983-07-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US9689418B2 (en) | Reduced-corrosion fastened assembly | |
| US4397726A (en) | Cathodically protected vessel | |
| JPS6312245Y2 (en) | ||
| KR0180705B1 (en) | Device for corrosion protection of shaft tube seal | |
| JPS63198214A (en) | Corrosion resistant insulator | |
| US3421990A (en) | Sacrificial anode | |
| JPS56146886A (en) | Production of coated type electrode of lead dioxide | |
| JPS5533726A (en) | Storage battery | |
| CN201614412U (en) | Corrosion-resistant device | |
| JPS6210633Y2 (en) | ||
| JPS5936895Y2 (en) | Transformer for underground installation | |
| JP2521981Y2 (en) | Stud bolt waterproof protector | |
| JPS6315330Y2 (en) | ||
| JPS6349044Y2 (en) | ||
| JP2000266027A (en) | Anchor bolt | |
| JPS59112286A (en) | Water-proof protection cover of stud bolt of reactor pressure vessel | |
| JP2003302488A (en) | Leak seal structure for nuclear reactor well water | |
| CN2167770Y (en) | Seawater pressure filter | |
| JP2607478Y2 (en) | Cathodic protection electrode structure for buried piping | |
| CA1114776A (en) | Electric current lead-in for electrolytic cells | |
| KR200486092Y1 (en) | Cathodic Protection Apparatus | |
| JP2003307583A (en) | Protective device for sheet surface | |
| JPS5942130B2 (en) | Installation method for bottom-mounted offshore structures | |
| JPS5819314Y2 (en) | Corrosion protection hardware for turbocharger cabin | |
| JPH0318504Y2 (en) |