JP5834817B2 - Electrodes for anticorrosion - Google Patents

Description

  The present invention relates to an electrode for cathodic protection for cathodic corrosion of land structures such as bridges, plants and steel towers.

  As a method for preventing the corrosion of onshore structures such as bridges, plants, steel towers, etc., there are an anticorrosion method and the like in addition to a general coating anticorrosion method by painting. In the case of cathodic protection, an electrode is connected between the base material and the electrode for cathodic protection provided on the coating so that the current flows when the coating is deteriorated, the coating is cracked or peeled off. This prevents corrosion of the material.

  For example, as a coating treatment when performing anticorrosion, an insulating paint (for example, epoxy resin) is coated on a steel member (base material) to form an insulating paint film, and the insulating paint film is electrically conductive. A conductive paint is applied to form a conductive paint film, and then a protective paint film is formed by applying a paint (for example, fluororesin or polyurethane resin) to protect the insulation paint film and the conductive paint film from UV and other factors that deteriorate over time. It is thought that the method of doing is suitable.

  Conventionally, in the case of performing anticorrosion, when an electroconductive coating film is formed, an electrode for anticorrosion is pasted on the electroconductive coating film, and a protective coating is applied on the electrode for anticorrosion.

  The substrate is a cathode (-) and the electrode for anticorrosion is an anode (+), and a DC voltage is applied between the electrodes.

  In a healthy state of the coating film, the current path is cut by the insulating coating film, and current hardly flows between the base material and the electrode for anticorrosion. When the coating film deteriorates and a crack or the like occurs in the coating film, water enters the crack, a water film is formed, and an electric current is passed between the base material and the electrode for anticorrosion through the water film and the conductive coating film. It will flow. In the energized state, the base material is connected to the cathode electrode, and the reverse electrical reaction when the base material corrodes is realized, and corrosion is prevented.

  As a conventional electrode for cathodic protection, a metal bar as an electrode is affixed with a tape or the like, a tape having a conductivity (metal tape or the like) is affixed, or an electrode member is bolted.

  In the method of sticking a metal bar with a tape or the like or sticking a conductive tape (metal tape or the like), the handling property of the electrode is poor and the workability of bonding is also poor. Furthermore, the adhesive interposed between the base material and the electrode for anticorrosion acts as a resistance and current does not flow easily, and the flowing range is narrow, so that a large number of electrodes for anticorrosion are required. Further, since the adhesive itself for attaching the electrode is a synthetic resin, it is deteriorated due to ultraviolet rays and the like, causing an increase in electric resistance due to material deterioration, an increase in electric resistance due to peeling of the electrode, and the like.

  Further, the method of attaching the electrode member with a bolt has a problem that the coated film may be damaged when the bolt is attached.

  Patent Document 1 discloses a stainless steel tape as an electrode used for cathodic protection and cathodic protection.

JP 2009-287075 A

  In view of such circumstances, the present invention provides an electrode for cathodic protection that can be easily installed, can prevent deterioration over time, and has low electrical resistance.

  The present invention relates to an electrode for anticorrosion formed on an insulating coating film and a conductive coating film on a base material, and affixed to the conductive coating film, and the contact surface of the electrode at a position protruding from the resin block An electrode for anticorrosion, in which a lead wire passing through the resin block is connected to the electrode, and a step filled with an adhesive for adhering the conductive coating film is formed around the contact surface It is concerned.

  The present invention also relates to an electrode for cathodic protection in which a lower central portion protruding from the lower end surface is formed on the resin block, and a plate-like electrode is attached to the lower surface of the lower central portion.

  The present invention also relates to an anticorrosion electrode in which a rod-like electrode is provided on the resin block, a lower end portion of the electrode protrudes from a lower surface of the resin block, and the step is formed around the lower end portion of the electrode. It is.

  The present invention also relates to an electrode for cathodic protection in which a groove surrounding the contact surface is formed.

  According to the present invention, an insulating coating film and a conductive coating film are formed on a base material, and the electrode is an anticorrosion electrode to be affixed to the conductive coating film. The electrode is disposed at a position protruding from the resin block and the resin block. Since a contact surface is provided, a lead wire passing through the resin block is connected to the electrode, and a step filled with an adhesive for adhering the conductive coating film is formed around the contact surface. The structure is easy to handle and the bonding work is easy, and the contact surface of the electrode is in direct contact with the conductive coating. Excellent effect that there is little deterioration.

It is sectional drawing of the electrode for cathodic protection which concerns on the 1st Example of this invention. (A) is explanatory drawing when a coating film is healthy when the said electrode for cathodic protection is stuck, (B) is explanatory drawing when a crack enters into a coating film. (A) is a bottom view of the electrode for cathodic protection according to the first embodiment, (B) is a bottom view showing a modified example of the first embodiment, and (C) is another modified example of the first embodiment. FIG. (A) is sectional drawing of the electrode for anticorrosion which concerns on a 2nd Example, (B) is sectional drawing of the example of a change of the electrode for anticorrosion which concerns on a 2nd Example. (A) is a fragmentary sectional view of the electrode for anticorrosion which concerns on a 3rd Example, (B) is a fragmentary sectional view of the example of a change of the electrode for anticorrosion which concerns on a 3rd Example.

  Embodiments of the present invention will be described below with reference to the drawings.

  A first embodiment will be described with reference to FIG.

  In FIG. 1, reference numeral 1 denotes an electrode for anticorrosion, and the electrode 1 for anticorrosion is composed of an electrode 2, a resin block 3, and lead wires 4.

  The electrode 2 has a flat circular shape, and the resin block 3 has an inverted convex shape with a lower end central portion 3a protruding downward, and a step is formed around the lower end central portion 3a. The electrode 2 is provided on the lower end surface of the lower end central portion 3a. The vertical cross section of the resin block 3 is an inverted convex shape as shown in the figure, and the flat cross sections of the main body portion 3b and the lower end central portion 3a of the resin block 3 are circular. The lower end center portion 3a and the main body portion 3b are formed concentrically. The lead wire 4 is joined to the electrode 2 through the main body portion 3b and the lower end central portion 3a.

  The electrode 2 is a conductive material, preferably an insoluble conductive material such as platinum, carbon, titanium or the like. The resin block 3 is preferably made of a material that can resist environmental degradation factors such as ultraviolet rays, such as fluororesin, polyurethane, and vinyl chloride.

  When manufacturing the electrode 1 for the anticorrosion, the lead wire 4 is first joined to the electrode 2. The joining may be a joining method having a small electric resistance between the electrode 2 and the lead wire 4 such as welding or soldering.

  The electrode 2 to which the lead wire 4 is bonded and the resin block 3 are integrally molded. In the integral molding, for example, the electrode 2 and the lead wire 4 are previously installed in a mold for molding the resin block 3, and a resin is molded into the mold. In addition, you may form the convex part for forming the said lower end center part 3a in a shaping | molding die, or after shape | molding a shaping | molding die as a cylinder, the circumference | surroundings of the said electrode 2 are excised and the said lower end center part 3a is formed. May be.

  When the electrode 1 for the anticorrosion is provided as an electrode, the electrode 2 is brought into contact with the conductive coating 6 and around the lower end central portion 3a (that is, the step portion surrounding the lower end central portion 3a). An adhesive 5, for example, an epoxy adhesive is filled to bond the main body 3 b and the conductive coating film 6. In the electrode 1 for anticorrosion, the main body portion 3 b and the conductive coating film 6 are bonded, and no adhesive is interposed between the electrode 2 and the conductive coating film 6. Therefore, the resistance between the electrode 2 and the conductive coating film 6 can be kept small. The adhesive 5 preferably has a volume that decreases when solidified. Due to the volume reduction at the time of solidification, the electrode 2 is pressed against the conductive coating film 6, the surface pressure between the electrode 2 and the conductive coating film 6 increases, and the contact resistance further decreases.

  With reference to FIGS. 2A and 2B, the action of the anti-corrosion when the electrode 1 for anti-corrosion is used will be described.

  An insulating paint is applied to the base material 7 to form an insulating paint film 8, and a conductive paint is further applied to the insulating paint film 8 to form a conductive paint film 9. The surface of the base material 7 is usually subjected to a rust prevention treatment such as coating with a zinc spray coating or a zinc-containing paint, but the description is omitted here.

  The electrode 1 for anticorrosion is placed on the conductive coating 9, and the electrode 1 for corrosion protection is bonded to the conductive coating 9 by the adhesive 5. The electrode 1 for electrocorrosion protection is bonded to the conductive coating film 9, whereby the electrode 2 and the conductive coating film 9 are in electrical contact, and the electrode 2 and the lead wire 4 are electrically connected.

  When the adhesion between the electrode 1 for anticorrosion and the conductive coating 9 is completed, a protective coating is applied on the conductive coating 9 to form a protective coating 10. The lead wire 4 is connected to a positive pole of a DC power source (not shown), the base material 7 is connected to a negative pole of a DC power source, and a voltage is applied between the electrode 2 and the base material 7.

  When the insulating coating 8, the conductive coating 9, and the protective coating 10 are in a healthy state, the electrode 2 and the substrate 7 are insulated by the insulating coating 8, and the electrode 2, No current flows between the base materials 7 (see FIG. 2A).

  When time passes and the protective coating film 10, the conductive coating film 9, and the insulating coating film 8 deteriorate and cracks 12 are generated, rainwater 13 penetrates into the cracks 12. The rainwater 13 conducts the electrode 2 and the base material 7, and a current flows between the electrode 2 and the base material 7. Here, the base material 7 is connected to the negative electrode and the electrode 2 is connected to the positive electrode, and the current flows between the base material 7 and the electrode 2, so that the base material 7 is corroded (oxidized). In this case, the reverse electric reaction is realized, and corrosion of the base material 7 is prevented.

  In the first embodiment, an epoxy resin or the like is used as the insulating coating 8, and a fluororesin or a polyurethane resin is used as the protective coating 10.

  In the first embodiment, since the resin block 3 is made of a material capable of resisting environmental degradation factors such as ultraviolet rays, the adhesive 5 includes the main body 3b, and further the protective coating. It is protected by the film 10, and the deterioration of the adhesion state between the electrode 1 for anticorrosion and the conductive coating film 9 is prevented.

  Further, the electrode 1 for the anticorrosion is a synthetic resin block in which the lead wire 4 is already connected to the electrode 2, and since it has a simple shape, it is easy to handle and easy to bond. is there.

  In addition, although the said Example demonstrated the anticorrosion, when the coating film (The said insulating coating film 8, the said conductive coating film 9, and the said protective coating film 10) cracked, the said electrode 2 is passed through the rain water 13 And between the base materials 7 is energized, it is possible to detect whether a crack has occurred by monitoring the energized state. Furthermore, by acquiring the correlation between the crack area and the current value as data in advance, the presence or absence of cracks can be detected by monitoring the presence or absence of energization, and the area of the crack can be determined by detecting the energization amount. It can be predicted, and can be used as a material for determining the appropriate timing of repainting.

  3 (A) to 3 (C) show modified examples of the electrode 1 for cathodic protection, and each show a bottom view.

  FIG. 3A shows a bottom view of the electrode 1 for cathodic protection shown in FIG. 3 (B), the main body 3b has a rectangular shape (bar shape), and the lower end central portion 3a protrudes from the bottom surface at a predetermined pitch in the longitudinal direction, and the bottom surface of the lower end central portion 3a is shown. The electrode 2 is fixed to the substrate. Each electrode 2 is connected to a lead wire 4 (not shown). In the electrode 1 for cathodic protection shown in FIG. 3B, since a plurality of electrodes 2 can be installed simultaneously, the workability of electrode installation is improved.

  In FIG. 3C, the main body portion 3b has a rectangular shape (bar shape), and the lower end central portion 3a also has a rectangular shape, and the cross section shown in FIG. 1 has a shape that is continuous in the longitudinal direction. . The electrode 2 fixed to the bottom surface of the main body portion 3b has a long rectangular shape (band shape). In the modification shown in FIG. 3C, the lead wire 4 only needs to be connected to the electrode 2 at one location.

  FIG. 4 shows a second embodiment of the electrode 1 for cathodic protection. In the second embodiment, a metal formed in a rod shape, such as aluminum, is used as the electrode 2.

  In FIG. 4A, the electrode 2 and the resin block 3 are integrally molded so that the lower end portion of the electrode 2 protrudes. In the second embodiment, the lower end portion of the electrode 2 protrudes, so that the lower end surface of the electrode becomes a contact surface, and a step is formed around the lower end portion. The adhesive 5 is filled in the steps around the electrode 2.

  FIG. 4B shows a modification of the second embodiment in which the exposed lower end of the electrode 2 has a large diameter and the portion held by the resin block 3 has a small diameter. In the embodiment shown in FIG. 4B, a hole may be formed in the resin block 3 in advance, and the small diameter portion of the electrode 2 may be press-fitted into the hole. In this case, the thin diameter portion of the electrode 2 penetrates the resin block 3 and the lead wire 4 is connected to the exposed upper end.

  FIG. 5 shows a third embodiment.

  5A is related to the electrode 1 for anticorrosion shown in FIG. 1 and FIG. 3B, and the diameter of the lower end central portion 3a protruding from the main body portion 3b is determined from the diameter of the contact surface of the electrode 2. A groove 15 is formed around the electrode 2 so as to surround the contact surface of the electrode 2. By forming the groove 15 around the electrode 2, the adhesive 5 is placed between the electrode 2 and the insulating coating 8 when the electrode 1 for anticorrosion is attached to the insulating coating 8. Even in the case of penetration, the groove 15 blocks the penetration of the adhesive. Therefore, the electrical contact between the electrode 2 and the insulating coating film 8 is maintained well.

  FIG. 5 (B) is related to the electrode 1 for anticorrosion shown in FIGS. 4 (A) and 4 (B), and a groove 15 is formed on the contact surface of the electrode 2 along the periphery. is there. Similar to the embodiment shown in FIG. 5 (A), the groove 15 blocks the penetration of the adhesive 5 into the center of the contact surface, and makes electrical contact between the electrode 2 and the insulating coating 8 (see FIG. 2). Hold well.

DESCRIPTION OF SYMBOLS 1 Electrodes for anticorrosion 2 Electrode 3 Resin block 4 Lead wire 5 Adhesive 6 Conductive coating 7 Base material 8 Insulating coating 9 Conductive coating 10 Protective coating 12 Crack 13 Rain water 15 Groove

Claims (3)

Insulating coating film, conductive coating film is formed on the base material, and the electrode for cathodic protection is affixed to the conductive coating film, with the lower end central portion of the resin block protruding downward, and on the lower surface of the lower end central portion A plate-like electrode having the same shape as the bottom surface of the lower end central portion is attached, a lead wire passing through the resin block is connected to the electrode, and the conductive coating film is adhered to the lower end central portion and the periphery of the electrode An electrode for cathodic protection, characterized in that a step filled with an adhesive is formed. Insulating coating film, conductive coating film is formed on the base material, and the electrode for cathodic protection is affixed to the conductive coating film, with the lower end central portion of the resin block protruding downward, and on the lower surface of the lower end central portion A plate-like electrode having a smaller diameter than the lower surface of the lower central portion is pasted so that the lower surface of the lower central portion and the contact surface of the electrode are flush with each other, and a lead wire passing through the resin block is attached to the electrode. are connected, characterized in that the lower step an adhesive is filled in order to adhere the conductive coating around the central portion is formed, a groove surrounding the electrode on the lower surface of the lower central portion is formed Electrodes for cathodic protection. Insulative coating on a substrate, a conductive coating film is formed, a sacrificial electrode which is affixed to the conductive coating film provided with a rod-shaped electrode such that the lower end portion of the resin block bottom surface in the resin block projects A contact surface having a diameter smaller than that of the lower end surface is provided on the lower end surface of the electrode, a lead wire that is inserted through the resin block is connected to the electrode, and an adhesive for adhering the conductive coating around the electrode An electrode for cathodic protection , wherein a step filled with an agent is formed, and a groove is formed on the lower end surface of the electrode along the periphery of the contact surface .

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