Anticorrosive tool, and installation method of anticorrosive tool

Abstract

To provide an anticorrosive tool that suppresses corrosion of an anchor bolt, and an installation method of an anticorrosive tool.SOLUTION: An anticorrosive tool 10 comprises: a terminal part 12 which is arranged in a space S between the anchor bolt 20 and the base plate 30 in a fitting hole 31 of a base plate 30 of a structure fixed by an anchor bolt 20, and contacts the anchor bolt 20; a sacrificial anode part 11 which is electrically connected to the terminal part 12, and is formed of a material having a larger ionization tendency than a material forming the anchor bolt 20; and an electrolyte part 14 which includes an electrolyte material, and contacts the sacrificial anode part 11 and the anchor bolt 20 in the state where the anticorrosive tool 10 is arranged in the space S.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a corrosion protection device, particularly to a corrosion protection device for anchor bolts, and to a method for installing the corrosion protection device. [Background technology]

[0002] Conventionally, when fixing various types of supports such as lighting poles and signposts, or steel structures such as bridges to underlying concrete structures, a commonly used method is to pass anchor bolts embedded in the concrete structure through mounting holes provided in the base plate (base) of the steel structure, and then tighten the bolts with nuts or other fasteners. Since steel structures such as lighting poles are placed outdoors, anchor bolts, nuts, etc. are exposed to the outdoor atmosphere for long periods of time, which makes them susceptible to corrosion such as rust. For this reason, various corrosion prevention devices have been developed (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-194491 [Patent Document 2] Japanese Patent Publication No. 2022-022860 Summary of the Invention [Problem to be solved by the invention]

[0004] The diameter of the mounting hole provided in the base plate is larger than the diameter of the anchor bolt, and a gap exists between the inner surface of the through hole and the outer surface of the anchor bolt. As mentioned above, steel structures such as lighting poles are installed outdoors, so rainwater seeps into this gap during rainy weather, and the rainwater evaporates and dries the gap during sunny weather. It is known that repeated wetting and drying due to rainwater over a long period of time can cause corrosion of the anchor bolt. If this corrosion progresses, the anchor bolt may lose thickness, resulting in a lack of strength.

[0005] The gap between the anchor bolt and the base plate in the mounting hole is small to begin with, and when the nut is fastened, it is hidden by the nut and cannot be seen from the outside. This makes it difficult to visually check the corrosion status of the anchor bolt, and the only effective corrosion prevention measure was to make the anchor bolt out of a corrosion-resistant material. However, anchor bolts made of corrosion-resistant materials are expensive and do not provide sufficient corrosion protection, making it difficult to prevent corrosion of the anchor bolts.

[0006] In view of the above, an object of the present invention is to provide a corrosion protector that suppresses corrosion of anchor bolts and a method for installing the corrosion protector. [Means for solving the problem]

[0007] The present invention solves the above problems by the following means.

[0008] (1) The present invention provides a corrosion protection device that is placed in a gap between an anchor bolt and a base plate in an attachment hole of a base plate of a structure fixed by the anchor bolt, the corrosion protection device comprising: a terminal portion that contacts the anchor bolt; a sacrificial anode portion that is electrically connected to the terminal portion and is formed of a material that has a greater ionization tendency than the material that forms the anchor bolt; and an electrolyte portion that contacts the sacrificial anode portion and the anchor bolt when the corrosion protection device is placed in the gap and contains an electrolyte material.

[0009] (2) The electrolyte portion may be formed from at least one of a gel electrolyte material formed into a sheet shape and a gel electrolyte material having fluidity.

[0010] (3) The electrolyte portion may be a porous body formed of a material having a higher ionization tendency than a material forming the anchor bolt, and may hold the electrolyte material in at least some of the pores.

[0011] (4) The corrosion protection device may be made up of a plurality of members each having a partial cylindrical shape, each of which includes the terminal portion, the sacrificial anode portion, and the electrolyte portion, and the plurality of members may be arranged so as to contact the outer periphery of the anchor bolt and fixed by a fixing member that fixes the position of the plurality of members in the radial direction of the anchor bolt.

[0012] (5) The terminal portion and the sacrificial anode portion are both cylindrical and connected in the axial direction or formed integrally, and the terminal portion may have a threaded portion on its inner surface that screws into the anchor bolt.

[0013] (6) At least the sacrificial anode portion may be a porous body.

[0014] (7) The electrolyte section may include a sheet-like or film-like current adjusting member having a plurality of openings formed therein.

[0015] (8) The present invention is a method for installing a corrosion protection device that is arranged in a mounting hole of a base plate of a structure fixed by an anchor bolt and includes a terminal portion that contacts the anchor bolt, a sacrificial anode portion that is electrically connected to the terminal portion and is formed of a material that has a greater ionization tendency than a material that forms the anchor bolt, and an electrolyte portion that contacts the sacrificial anode portion and the anchor bolt and includes an electrolyte material, the method comprising: a bolt-side electrolyte portion arrangement step of providing a bolt-side electrolyte portion that includes an electrolyte material on the outer peripheral surface of the anchor bolt located in the mounting hole; and a corrosion protection device arrangement step of arranging the corrosion protection device in the gap between the anchor bolt and the base plate in the mounting hole in a state where the electrolyte portion is integrated with the bolt-side electrolyte portion and contacts the anchor bolt. [Effects of the Invention]

[0016] According to the present invention, an object of the present invention is to provide a corrosion protector that suppresses corrosion of anchor bolts and a method for installing the corrosion protector. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a perspective view of a corrosion protector 10 according to a first embodiment. [Figure 2] FIG. 1 is an end view of a corrosion protector 10 according to a first embodiment. [Figure 3] 2 is a diagram illustrating a gap S between an anchor bolt 20 and a base plate 30 into which the corrosion protector 10 of the first embodiment is inserted. FIG. [Figure 4] 1 is an end view showing a state in which the corrosion protector 10 of the first embodiment is installed on an anchor bolt 20. FIG. [Figure 5] 10 is a diagram illustrating a corrosion protector 210 according to a second embodiment. FIG. [Figure 6] 10 is a diagram illustrating a corrosion protector 310 according to a third embodiment. FIG. [Figure 7] 10 is a diagram illustrating a fixing ring 319 for fixing a first member 310A and a second member 310B of a corrosion protector 310 according to a third embodiment. FIG. [Figure 8] 10 is an end view showing a state in which a corrosion protector 310 of a third embodiment is installed on an anchor bolt 20. FIG. [Figure 9] FIG. 10 is a top view showing a state in which a corrosion protector 410 of a fourth embodiment is installed on an anchor bolt. [Figure 10] 10 is a diagram illustrating a corrosion protector 510 according to a fifth embodiment. FIG. [Figure 11] FIG. 10 is a plan view illustrating a current adjusting member 515. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings, etc. Note that the drawings shown below, including Fig. 1, are schematic diagrams, and the size and shape of each part are appropriately exaggerated to facilitate understanding. Furthermore, the numerical values ​​such as dimensions of each component and the names of materials described in this specification are examples of embodiments, and are not limited to these, and may be selected and used as appropriate.

[0019] (First embodiment) FIG. 1 is a perspective view of a corrosion protector 10 according to a first embodiment. 2 is an end view of the corrosion protector 10 of the first embodiment. In FIG. 2, the end surface cut along the arrow BB shown in FIG. 3 is a diagram illustrating the gap S between the anchor bolt 20 into which the corrosion protector 10 of the first embodiment is inserted and the base plate 30. FIG. 3 shows a cross section of the anchor bolt 20 inserted into the mounting hole 31 of the base plate 30. FIG. 4 is an end view showing the corrosion protector 10 of the first embodiment installed on the anchor bolt 20. As shown in FIG.

[0020] 1 and other figures show an axis A that passes through the center of the corrosion protector 10 and is parallel to the height direction. In the direction of this axis A, the upper side of the corrosion protector 10 in use is the +A direction, and the lower side is the -A side. 3 and 4, for ease of understanding, the central axis of the anchor bolt 20, the central axis of the mounting hole 31, and axis A, which is the central axis of the corrosion protector 10, are shown aligned, and the central axes of the anchor bolt 20 and the mounting hole 31 are omitted. For ease of understanding, the uneven shape of the threads provided on the outer peripheral surface of the anchor bolt 20 is omitted from the illustration in FIG. 3 and other figures.

[0021] First, the anchor bolt 20, base plate 30, concrete structure 40, etc. on which the corrosion protector 10 of this embodiment is disposed will be described. The concrete structure 40 is a base for fixing supports such as lighting poles and sign poles, and bridges, in place.

[0022] The anchor bolt 20 is a rod-shaped bolt with a male thread formed on its outer circumferential surface, one end of which is embedded in the concrete structure 40 and the other end of which is exposed from the concrete structure 40. The portion embedded in the concrete structure 40 is called the embedded portion or the like. Here, the portion exposed from the concrete structure 40 will be referred to simply as the anchor bolt 20 in the following description. The anchor bolt 20 is made of steel such as carbon steel, and the length of the anchor bolt 20 (the axial dimension of the portion exposed from the concrete structure 40) is greater than the thickness of the base plate 30. In this embodiment, an example will be described in which the anchor bolt 20 is exposed so as to extend vertically upward from the surface of the concrete structure 40.

[0023] The base plate 30 is placed on the surface of the concrete structure 40 and serves as a base for fixing various supports, bridges, etc. to the concrete structure 40. The base plate 30 is in the shape of a plate or the like, and is made of a metal such as steel, and is provided with a plurality of mounting holes 31, which are through holes into which the anchor bolts 20 can be inserted. The mounting holes 31 penetrate the base plate 30 in the thickness direction thereof, and have circular openings. The number of mounting holes 31 provided in the base plate 30, the positions of the mounting holes provided in the base plate 30, etc. may be set as appropriate.

[0024] The diameter of the mounting hole 31 is larger than the diameter of the anchor bolt 20. Therefore, as shown in Figure 3, when the anchor bolt 20 is inserted into the mounting hole 31 of the base plate 30 and the base plate 30 is placed on the surface of the concrete structure 40, a gap S is generated between the inner peripheral surface of the mounting hole 31 of the base plate 30 and the outer peripheral surface of the anchor bolt 20. The width of this gap S in the radial direction of the mounting hole 31 is about several millimeters.

[0025] The corrosion protector 10 of this embodiment has a cylindrical shape and can have the anchor bolt 20 inserted into its hollow portion. Furthermore, the corrosion protector 10 is placed in the gap S between the anchor bolt 20 and the base plate 30 in the mounting hole 31 with the anchor bolt 20 inserted into the hollow portion. The outer diameter of the corrosion protector 10 as viewed in the direction of axis A is smaller than the inner diameter of the mounting hole 31, and the inner diameter of the hollow portion of the corrosion protector 10 is equal to or larger than the outer diameter of the anchor bolt 20. In this embodiment, the dimension of the corrosion protector 10 in the direction of axis A (the height of the corrosion protector 10) is equal to or smaller than the depth of the mounting hole 31 in the base plate 30.

[0026] The corrosion protector 10 includes a sacrificial anode portion 11, a terminal portion 12, a holding portion 13, and an electrolyte portion 14. The main body portion of the corrosion protector 10, which is made up of the sacrificial anode portion 11 and the terminal portion 12, is preferably made of a material having a higher ionization tendency than iron, particularly a metal material having a higher ionization tendency than iron. Examples of such metal materials include aluminum, zinc, and alloys thereof. In the corrosion protector 10 of this embodiment, the main body portion is made of an aluminum alloy, for example.

[0027] The sacrificial anode part 11 of this embodiment has a cylindrical shape and corresponds to the part from one end (-A side) in the axial A direction to the terminal part 12 on the other end (+A side). The terminal portion 12 is a cylindrical portion located at the other end (+A side) of the sacrificial anode portion 11 in the axial A direction. The radial thickness of the terminal portion 12 is greater than that of the sacrificial anode portion 11. Therefore, the diameter of the inner peripheral surface of the terminal portion 12 is smaller than the diameter of the inner peripheral surface of the sacrificial anode portion 11. The terminal portion 12 and the sacrificial anode portion 11 may be integrally formed, or may be joined by a conductive adhesive or the like (not shown), or may be connected along the axial A direction. When the anchor bolt 20 is inserted into the hollow portion of the corrosion protector 10, the inner peripheral surface of the terminal portion 12 comes into contact with the anchor bolt 20, providing electrical conductivity. The terminal portion 12 of this embodiment has an internal thread formed on its inner peripheral surface that screws into a male thread formed on the outer peripheral surface of the anchor bolt 20. Therefore, the corrosion protector 10 comes into contact with the anchor bolt 20 at the terminal portion 12 and is screwed together.

[0028] The holding portions 13 are concave portions formed on the end face (end face on the +A side) that becomes the upper face when the corrosion protector 10 is placed in the gap S. In this embodiment, the holding portions 13 are rectangular recesses when viewed from the side (radial side) of the corrosion protector 10, and four of the holding portions 13 are formed at equal intervals around the circumference of the corrosion protector 10. The retaining portion 13 engages with the protrusion of a fixing device (not shown), and by rotating the fixing device in the engaged state, the corrosion protection device 10 can be threaded onto the anchor bolt 20 and inserted into the mounting hole 31 until the lower end reaches the surface of the concrete structure 40. Therefore, the shape and number of the holding parts 13 may be changed as appropriate depending on the fasteners used, etc. Also, the corrosion protector 10 may have no holding parts 13.

[0029] The electrolyte portion 14 is a portion made of an electrolyte material that is provided between the anchor bolt 20 and the sacrificial anode portion 11 so as to be in contact with both when the corrosion protector 10 is placed in the gap S between the anchor bolt 20 and the base plate 30. The electrolyte portion 14 of this embodiment is formed of a viscous gel-like electrolyte material. The electrolyte portion 14 is provided by applying the gel-like electrolyte material to the inner peripheral surface of the sacrificial anode portion 11 or by attaching a sheet-like material made of the gel-like electrolyte material. In order to prevent the gel electrolyte material from drying out, the electrolyte part 14 of this embodiment is preferably in a form in which a film-like member (not shown) or the like is laminated on its inner peripheral surface during storage before use. In this case, the film material is peeled off when the electrolyte part 14 is installed on the anchor bolt 20 in the mounting hole 31.

[0030] It is preferable to provide an insulating layer (not shown) on the outer peripheral surface of the corrosion protector 10, particularly on the outer peripheral surface of the sacrificial anode portion 11, by wrapping insulating tape (not shown, such as Nitoflon tape manufactured by Nitto Denko Corporation). By adopting such a configuration, the base plate 30 and the corrosion protector 10 are not electrically connected, preventing corrosion current from flowing toward the base plate 30 and enhancing the effect of the corrosion protector 10 in suppressing corrosion of the anchor bolt 20. However, this is not limiting, and an insulating sheet or the aforementioned insulating tape may be attached to the inner peripheral surface of the mounting hole 31 to prevent electrical connection between the base plate 30 and the corrosion protector 10.

[0031] Here, the dimensions of each part of the anticorrosion device 10 and the mounting hole 31 in this embodiment are exemplified. Note that this is just one example of this embodiment, and the dimensions of each part are not limited to these. The corrosion protector 10 has an outer diameter of 28 mm, a height of 24 mm, an inner diameter of the sacrificial anode 11 of 26 mm, and a dimension of the terminal 12 in the direction of axis A of 4 mm. The electrolyte 14 is formed of a sheet-like member with a thickness of 1 mm. The holding portion 13 has a width (the dimension in the circumferential direction of the cylindrical shape) of 6 mm and a depth of 3 mm. The anchor bolt 20 has a diameter (nominal diameter) of 24 mm, the attachment hole 31 has a diameter of 30 mm, and the depth (axial dimension) corresponds to the thickness of the base plate 30, which is 25 mm.

[0032] The method of installing the corrosion protector 10 of this embodiment will be described below. First, the worker places the base plate 30, to which supports (not shown) and the like are fixed, on the concrete structure 40. At this time, the anchor bolts 20 are inserted into the mounting holes 31.

[0033] Next, the worker inserts the anchor bolt 20 into the hollow portion of the corrosion protector 10 so that the terminal portion 12 side of the corrosion protector 10 is on the upper side (+A side, opposite the concrete structure 40 side), screws the threaded portion of the anchor bolt 20 into the threaded portion 12a of the terminal portion 12, and uses a fixing device (not shown) to insert the corrosion protector 10 into the gap S until the lower end (the surface on the -A side) of the sacrificial anode portion 11 comes into contact with the surface of the concrete structure 40. In this way, the corrosion protector 10 is positioned in the gap S. At this time, the electrolyte portion 14 is in contact with the anchor bolt 20 and the sacrificial anode portion 11, and the terminal portion 12 is in contact with the anchor bolt 20 at the threaded portion 12a.

[0034] Next, the worker attaches the washer 51 to the anchor bolt 20 and fastens the base plate 30 and the anchor bolt 20 with the nut 52. In this way, the support pillar (not shown) or the like is fixed to the concrete structure 40.

[0035] It is preferable to apply a fluid, gel-like electrolyte material to the threaded portion on the outer circumferential surface of the anchor bolt 20 located in the mounting hole 31 of the base plate 30 in advance to provide a bolt-side electrolyte portion (not shown) (bolt-side electrolyte portion placement step), and then install the corrosion protector 10 on the anchor bolt 20 as described above and place it in the gap S of the mounting hole 31 with the anchor bolt 20 and the electrolyte portion 14 in contact with each other via the bolt-side electrolyte portion (corrosion protector placement step). By adopting this configuration, when the corrosion protector 10 is installed on the anchor bolt 20 in the mounting hole 31, the electrolyte portion 14 provided on the corrosion protector 10 side and the bolt-side electrolyte portion (i.e., the fluid, gel-like electrolyte material) provided on the outer circumferential surface of the anchor bolt 20 come into close contact with each other and become one body, contacting the anchor bolt 20. This improves conductivity between the anchor bolt 20 and the electrolyte portion 14, making it possible to generate a corrosion current more effectively. In this case, it is more preferable to apply the electrolyte material so that the outer diameter of the outer peripheral surface of the anchor bolt 20 when coated with the electrolyte material is slightly larger than the inner diameter of the electrolyte section 14 of the corrosion protector 10, from the viewpoint of improving the conductivity between the anchor bolt 20 and the electrolyte section 14.

[0036] As described above, the sacrificial anode portion 11 is formed of a material (for example, an aluminum alloy in this embodiment) that has a higher ionization tendency than the anchor bolt 20. Furthermore, as shown in FIG. 4 , when the corrosion protector 10 is placed in the gap S, the electrolyte portion 14 contacts both the anchor bolt 20 and the sacrificial anode portion 11, and the terminal portion 12 contacts the anchor bolt 20. By disposing such a corrosion protector 10 in the gap S, a corrosion current is generated between the sacrificial anode part 11, the anchor bolt 20, and the electrolyte part 14, causing corrosion of the sacrificial anode part 11, which has a higher ionization tendency than the anchor bolt 20. As a result, according to this embodiment, the corrosion protector 10 can suppress corrosion of the anchor bolt 20.

[0037] The electrolyte part 14 is made of a gel-like electrolyte material, and when it dries and the water content decreases, the conductivity decreases, the corrosion current decreases, and sufficient corrosion protection is not achieved. Therefore, in this embodiment, as shown in Figure 4, after placing the corrosion protector 10 in the gap S, a sealant made of silicone or the like (for example, one-component RTV rubber manufactured by Shin-Etsu Silicones) may be filled into the gap between the outer peripheral surface of the corrosion protector 10 and the inner peripheral surface of the mounting hole 31 to form a sealing layer 15 and seal the gap.

[0038] Furthermore, a sealing layer 16 may be formed using a resin sealant (for example, a multi-purpose seal manufactured by Konishi Co., Ltd. or petrolatum manufactured by Nitto Denko Corporation) to seal the gap that occurs in the direction of axis A between the upper end surface of the corrosion protector 10 (the end surface on the +A side, which in this embodiment is the end surface on which the retaining portion 13 is formed) and the upper surface of the base plate 30. The anchor bolt 20 and the base plate 30 are fastened with nuts 52 after these sealing operations. The sealing layer 15 and the sealing layer 16 may be formed using the same material. In addition, a layer of a sealing material or the like may also be provided between the concrete structure 40 and the lower end surface (-A side end surface) of the corrosion protector 10.

[0039] By adopting such a configuration, evaporation of the water contained in the electrolyte portion 14 is suppressed, and the anticorrosion effect can be maintained for a long period of time. Note that such sealing layers 15, 16 may be formed in a configuration in which only one of them is formed, or in which both are formed, or in which neither is formed, and the configuration may be selected appropriately.

[0040] (Second embodiment) The anticorrosion device 210 of the second embodiment has a porous portion 215, which functions as an electrolyte portion, and is otherwise similar to the anticorrosion device 10 of the first embodiment. Therefore, in the following description, parts that perform the same functions as those of the first embodiment described above will be given the same reference numerals, and duplicate descriptions will be omitted where appropriate.

[0041] 5 is a diagram illustrating a corrosion protector 210 according to a second embodiment. In FIG. 5, an end face corresponding to the end face of the corrosion protector 10 according to the first embodiment shown in FIG. The corrosion protector 210 of the second embodiment has a porous portion 215 of a predetermined thickness provided on the inner periphery of the sacrificial anode portion 11. The porous portion 215 is formed of a porous material having a plurality of pores. A sintered body or the like made of a material with a higher ionization tendency than iron is preferable as the porous material. In this embodiment, the porous portion 215 is described as being an aluminum alloy sintered body, but is not limited thereto. The porous portion 215 may be a zinc sintered body, an aluminum alloy, a zinc alloy sintered body, or the like. The porous portion 215 is integrally joined to the sacrificial anode portion 11 by being attached to the inner periphery of the sacrificial anode portion 11 with a conductive adhesive or the like (not shown) or by being press-fitted into the inner diameter of the sacrificial anode portion 11.

[0042] As will be described later, the porous portion 215 functions as an electrolyte portion by retaining rainwater and the like in its pores. In this embodiment, when the corrosion protector 210 is installed on the anchor bolt 20, the inner circumferential surface of the porous portion 215 is in contact with the anchor bolt 20. However, this is not limited to this, and the porous portion 215 may have a female thread formed on its inner circumferential surface so as to be threadedly engaged with the anchor bolt 20, similar to the terminal portion 12, so as to be in threaded contact with the anchor bolt 20. By adopting such a configuration, the contact area between the porous portion 215 and the anchor bolt 20 can be increased, which is preferable from the viewpoint of improving the conductivity of the corrosion current.

[0043] In this embodiment, when the corrosion protector 210 is placed in the gap S, it is not sealed with a sealant or the like, but is configured to allow rainwater and the like to enter the gap S. As a result, the rainwater and the like that enters the gap S penetrates into the corrosion protector 210 and penetrates into the pores of the porous portion 215 and is retained therein. The rainwater and the like retained in the porous portion 215 is an electrolyte material containing many impurities. Therefore, the porous portion 215 that retains the rainwater and the like functions as an electrolyte portion.

[0044] For example, in an environment where water is likely to seep into the gap S, such as in a tropical region where there is a lot of rainfall throughout the year, or near a waterfall, river, or ocean, the porous portion 215 functions as an electrolyte portion by retaining water such as rainwater that has seeped into the pores. This allows a corrosion current to flow between the anchor bolt 20, the sacrificial anode portion 11, and the porous portion 215, causing the sacrificial anode portion 11 to corrode preferentially over the anchor bolt 20, thereby suppressing corrosion of the anchor bolt 20. Therefore, the corrosion protector 210 of this embodiment is effective when used in such an environment.

[0045] The corrosion protector 210 of this embodiment is installed on the anchor bolt 20 in the mounting hole 31 by the same installation method as the corrosion protector 10 of the first embodiment described above. In this embodiment as well, it is preferable to first apply a gel-like electrolyte material having fluidity to the outer peripheral surface of the anchor bolt 20 located in the mounting hole 31 to provide a bolt-side electrolyte portion (not shown), and then place the corrosion protector 210 in the gap S in contact with the anchor bolt 20. This causes the electrolyte material held in the pores of the porous portion 215 and the bolt-side electrolyte portion to come into contact with the anchor bolt 20 as a single unit, improving adhesion between the porous portion 215, which functions as the electrolyte portion, and the anchor bolt 20, and improving conductivity between the anchor bolt 20, the sacrificial anode portion 11, and the porous portion 215.

[0046] As described above, in this embodiment, as in the first embodiment, the corrosion protector 210 can suppress corrosion of the anchor bolt 20. Furthermore, since the corrosion protector 210 includes the porous portion 215, it is possible to ensure electrical conductivity as an electrolyte portion by retaining rainwater or the like in the pores, without providing a new electrolyte portion 14. This makes it easy to install the corrosion protector 210.

[0047] In this embodiment, the inner circumferential surface of the porous portion 215 is in contact with the anchor bolt 20 when the corrosion protector 210 is installed on the anchor bolt 20, but this is not limiting, and for example, the diameter of the inner circumferential surface of the porous portion 215 may be larger than the outer diameter of the anchor bolt 20, and the inner circumferential surface of the porous portion 215 may not be in contact with the anchor bolt 20 when the corrosion protector 210 is installed on the anchor bolt 20. In this case, the porous portion 215 and the anchor bolt 20 may be in contact with each other via the electrolyte portion 14, for example, by forming an electrolyte portion 14 on the inner circumferential surface side of the porous portion 215.

[0048] In addition, in this embodiment, as shown in Figure 5, an example is shown in which the porous portion 215 is formed to cover the inner surface of the sacrificial anode portion 11, but this is not limited to this, and for example, the dimension of the porous portion 215 in the direction of axis A may be shorter than that of the sacrificial anode portion 11. Furthermore, in this embodiment, an example in which the porous portion 215 is provided continuously in the circumferential direction is described, but a form in which voids are arranged at predetermined intervals in the circumferential direction may also be used.

[0049] Furthermore, in this embodiment, an example has been shown in which the porous portion 215 is provided on the inner circumferential side of the sacrificial anode portion 11, but this is not limiting, and the sacrificial anode portion 11 may be formed from a porous material. Alternatively, the sacrificial anode portion 11 may be formed from a porous material, and a threaded portion (not shown) may be formed on its inner circumferential surface to thread onto a threaded portion formed on the outer circumferential surface of the anchor bolt 20, so that when the corrosion protector 210 is installed on the anchor bolt 20, the sacrificial anode portion 11 and the anchor bolt 20 are threadedly engaged and in contact with each other. In this case, the terminal portion 12 may also be formed from a porous material, and the entire corrosion protector 210 may be formed from a porous material. Such porous materials are preferably sintered bodies of metal materials having a higher ionization tendency than iron, such as sintered bodies of aluminum or zinc, or sintered bodies of aluminum alloys or zinc alloys.

[0050] Furthermore, in this embodiment, for example, before installing the corrosion protector 210 on the anchor bolt 20, an electrolyte material may be filled in the pores of the porous portion 215 in advance. In this case, a gel-like electrolyte material such as the electrolyte portion 14 may be used, or an electrolyte material having fluidity may be used. Alternatively, the electrolyte material may be filled not in the entire porous portion 215, but at least in the pores located on the inner periphery of the porous portion 215. Alternatively, the pores of the porous portion 215 may be filled with the electrolyte material, and further, a viscous gel-like electrolyte portion 14 as shown in the first embodiment may be provided on the inner periphery of the porous portion 215. In this configuration, the electrolyte material is filled into the pores, thereby reducing drying and outflow of the electrolyte material. Furthermore, rainwater or the like that has entered the gap S penetrates into the pores of the porous portion 215, thereby preventing the electrolyte material or the like that has filled the pores from drying out.

[0051] (Third embodiment) The corrosion protector 310 of the third embodiment has the same configuration as the corrosion protector 10 of the first embodiment, except that the cylindrical shape is divided into multiple members in the circumferential direction. Therefore, in the following description, parts that perform the same functions as those of the first embodiment described above will be given the same reference numerals, and duplicate descriptions will be omitted as appropriate.

[0052] Fig. 6 is a diagram illustrating a third embodiment of a corrosion protector 310. Fig. 6(a) is a top view of the corrosion protector 310, and Fig. 6(b) is an end view of the corrosion protector 310. The end face of the corrosion protector 310 shown in Fig. 6(b) is the end face cut along arrow CC shown in Fig. 6(a). FIG. 7 is a diagram illustrating a fixing ring 319 for fixing a first member 310A and a second member 310B of a corrosion protector 310 according to the third embodiment. Fig. 8 shows a state in which a corrosion protector 310 of the third embodiment is installed on an anchor bolt 20. In Fig. 8, for ease of understanding, the base plate 30, nuts 52, etc. are omitted. The corrosion protector 310 of the third embodiment is configured by fixing a first member 310A and a second member 310B to the anchor bolt 20 with a fixing ring 319 so that they are integrated together. Since the first member 310A and the second member 310B have the same shape, the first member 310A will be used as an example for explanation.

[0053] The first member 310A has a sacrificial anode portion 311, an electrolyte portion 314, and an electrode terminal portion 316. In this embodiment, the first member 310A has a partial cylindrical shape and is arc-shaped when viewed from the direction of the axis A, and the angle formed by both ends of the first member 310A and the axis A is, for example, 150°. However, this angle is not limited to this and can be set up to a maximum of 180°. The electrode terminal portion 316 has a terminal portion 317 and a connecting portion 318. The terminal portion 317 is a plate-like member that is arcuate when viewed in the direction of axis A. Furthermore, a thin plate-like connecting portion 318 is integrally connected to the lower side (-A side) of the terminal portion 317 in the direction of axis A. The inner peripheral surface of the terminal portion 317 becomes the terminal that comes into contact with the anchor bolt 20 when assembled to the anchor bolt 20.

[0054] 6(b), the connecting portion 318 is a thin plate-like member having an L-shaped cross section. The upper end (+A side) of the connecting portion 318 is provided along the radial direction (direction intersecting with the axis A), and the terminal portion 317 is connected to the upper surface of the connecting portion 318. The lower end (-A side) of the connecting portion 318 extends in the direction of the axis A. The connecting portion 318 is, for example, a stainless steel member having a thickness of 0.2 mm.

[0055] The sacrificial anode part 311 is provided with a predetermined thickness inside the part of the connecting part 318 that extends in the direction of the axis A, and this sacrificial anode part 311 is joined to the connecting part 318 with a conductive adhesive (not shown) as described above. Therefore, there is electrical continuity between the connecting part 318 and the sacrificial anode part 311. This sacrificial anode part 311 has a thickness of, for example, 1.2 mm and is made of an aluminum alloy. In this embodiment, the electrode terminal portion 316 and the sacrificial anode portion 311 form the main body of the corrosion protector 310.

[0056] The electrolyte portion 314 is provided with a predetermined thickness on the inner circumferential side of the sacrificial anode portion 311. The electrolyte portion 314 of this embodiment is formed of a gel electrolyte material, similar to the electrolyte portion 14 of the first embodiment. Furthermore, when the corrosion protector 310 is installed on the anchor bolt 20, the inner circumferential surface of the electrolyte portion 314 contacts the anchor bolt 20.

[0057] Fixing ring 319 has a shape in which a portion of a circular ring is cut out. Fixing ring 319 has a thickness (dimension in the direction of axis A) that is the same as the dimension in the direction of axis A of terminal portion 317. Furthermore, fixing ring 319 has a width (dimension in the radial direction) that is approximately the same as the dimension in the radial direction between the outer circumferential surface of terminal portion 317 and the outer circumferential surface of connecting portion 318 of first member 310A, etc. This results in a shape in which fixing ring 319 does not protrude when attached to the outside of each terminal portion 317 of corrosion protector 310. The fixing ring 319 may be made of metal, resin, etc. In this embodiment, the fixing ring 319 is made of stainless steel.

[0058] A method for installing the corrosion protector 310 of this embodiment will be described. In this embodiment as well, it is preferable to apply a fluid gel electrolyte material to the outer peripheral surface of the anchor bolt 20 located in the mounting hole 31 in advance to provide a bolt-side electrolyte portion (not shown).

[0059] Next, using a tool or the like not shown, the worker inserts the first member 310A and the second member 310B, which are corrosion protection tools 310, into the gap S between the anchor bolt 20 and the base plate 30, and presses the electrolyte part 314 against the anchor bolt 20. Next, the worker fits fixing ring 319 onto the outside of terminal portion 317, and fixes anchor bolt 20 and corrosion protector 310 (first member 310A, second member 310B). In this way, corrosion protector 310 is installed on anchor bolt 20 within mounting hole 31.

[0060] Even in this configuration, as in the first embodiment, the corrosion protector 310 can exert the effect of suppressing corrosion protection of the anchor bolt 20. Furthermore, according to this embodiment, the corrosion protector 310 can be more easily placed in the gap S, and the work of attaching and detaching it to and from the anchor bolt 20 can be easily performed.

[0061] In this embodiment, the corrosion protector 310 is shown as having a first member 310A and a second member 310B that are part of a cylindrical shape, but this is not limited to this, and the cylindrical shape may also be formed from three or more members. Furthermore, in this embodiment, an example has been shown in which the first member 310A and the second member 310B are fixed in a state in contact with the anchor bolt 20 by the fixing ring 319, but, for example, the first member 310A and the second member 310B may be arranged to be in contact with the anchor bolt 20 in the gap S, and for example, a wedge-shaped member or the like may be driven into the gap between the first member 310A and the second member 310B and the base plate 30 to fix them.

[0062] (Fourth embodiment) The corrosion protector 410 of the fourth embodiment has the same configuration as the corrosion protector 10 of the first embodiment, except that it has a partial cylindrical shape, is arc-shaped when viewed from the direction of axis A, and covers part of the outer periphery of the anchor bolt 20. Therefore, in the following description, parts that perform the same functions as those of the first embodiment described above will be given the same reference numerals, and duplicate descriptions will be omitted as appropriate. Fig. 9 is a top view showing a state in which a corrosion protector 410 of the fourth embodiment is installed on an anchor bolt 20. In Fig. 9, the shape of the corrosion protector 410 and the like is shown in a simplified manner for ease of understanding.

[0063] Depending on the attachment position of the anchor bolt 20 to the concrete structure 40 and the position of the attachment hole 31 in the base plate 30, the central axis A1 of the anchor bolt 20 and the central axis A2 of the attachment hole 31 may not coincide. If the central axis A1 of the anchor bolt 20 and the central axis A2 of the attachment hole 31 are slightly misaligned, the corrosion protectors 10, 210, 310 of the first to third embodiments described above can be used.

[0064] The distance d between the central axis A1 of the anchor bolt 20 and the central axis A2 of the mounting hole 31 is a maximum of d = 3 mm when the diameter (nominal diameter) of the anchor bolt 20 is 24 mm and the diameter of the mounting hole 31 is 30 mm, as in this embodiment. Figure 9 shows an example where d = 3 mm, and the anchor bolt 20 is in contact with the inner circumferential surface of the mounting hole 31. In such a case, there is not enough clearance between the anchor bolt 20 and the inner surface of the mounting hole 31, and the cylindrical corrosion protection device 10, 210 as shown in the first and second embodiments cannot be attached to the anchor bolt 20. Therefore, in this embodiment, a corrosion protector 410, which is a part of a cylindrical shape, is brought into close contact with part of the outer periphery of the anchor bolt 20 and fixed by a spacer 60 to suppress corrosion.

[0065] The corrosion protector 410 of this embodiment is a partial cylindrical shape, has an arc shape when viewed from the direction of axis A, and is so-called a split shape. Like the first embodiment, this corrosion protector 410 includes a sacrificial anode portion, a terminal portion, and an electrolyte portion. As with the first embodiment, the electrolyte portion uses a sheet of gel electrolyte material. Note that the main body portion of the corrosion protector 410 (the sacrificial anode portion and the terminal portion) may be formed by cutting the main body portion formed in a cylindrical shape like the first embodiment in half along the direction of axis A.

[0066] A method for installing the corrosion protector 410 of this embodiment will be described. First, the worker fills the gap S between the mounting hole 31 of the base plate 30 and the anchor bolt 20 with a gel-like electrolyte material G that has low viscosity and fluidity. As a result, a bolt-side electrolyte portion (not shown) is provided on the outer circumferential surface of the anchor bolt 20 using the electrolyte material G. The corrosion protector 410 is placed into the gap S filled with the electrolyte material G and pressed against the anchor bolt 20, and is aligned so that the threaded portion of the terminal portion of the corrosion protector 410 and the threaded portion of the anchor bolt 20 engage with each other.

[0067] Next, a cylindrical spacer 60 is prepared, and inserted into the wide portion of gap S between the inner circumferential surface of mounting hole 31 and corrosion protector 410, and then moved so as to press spacer 60 into the narrow space, forcing it between the inner circumferential surface of mounting hole 31 and corrosion protector 410 to fix corrosion protector 410. In this embodiment, two spacers 60 are used, and the position of corrosion protector 410 relative to anchor bolt 20 is fixed at two points.

[0068] As a result, the bolt-side electrolyte part on the outer circumferential surface of the anchor bolt 20 and the electrolyte part of the corrosion protector 410 come into close contact and become one body. Then, with the electrolyte part of the corrosion protector 410 and the bolt-side electrolyte part being one body and in contact with the anchor bolt 20, the corrosion protector 410 is fixed to the anchor bolt 20, and the corrosion protector 410 and the anchor bolt 20 are stably connected both mechanically and electrically.

[0069] It is preferable to use a material having elasticity (spring properties) for the spacer 60. By forcing the elastic spacer 60 into the narrow portion of the gap S between the corrosion protector 410 and the inner circumferential surface of the mounting hole 31, the corrosion protector 410 can be sufficiently pressed against the anchor bolt 20 and fixed. The spacer 60 may be made of metal, resin, or rubber. The spacers 60 may be arranged in three or more locations, and the spacers may have different diameters. In addition, in order to prevent corrosion current from leaking toward the base plate 30, it is preferable to attach an insulating sheet-like material or the aforementioned insulating tape to the inner surface of the mounting hole 31 in order to enhance the corrosion prevention effect.

[0070] According to this embodiment, even if the central axis A1 of the anchor bolt 20 and the central axis A2 of the mounting hole 31 are not aligned but are eccentric, the corrosion inhibitor 410 can be placed in the gap S, and the corrosion inhibitor 410 can sufficiently suppress corrosion of the anchor bolt 20.

[0071] (Fifth embodiment) The corrosion protector 510 of the fifth embodiment has the same configuration as the corrosion protector 10 of the first embodiment, except that a current adjusting member 515 is provided in the electrolyte section 514. Therefore, in the following description, parts that perform the same functions as those in the first embodiment described above will be given the same reference numerals, and duplicate descriptions will be omitted as appropriate. Fig. 10 is a diagram illustrating a corrosion protector 510 according to the fifth embodiment. The end face shown in Fig. 10 corresponds to the end face shown in Fig. 2 in the first embodiment. FIG. 11 is a plan view illustrating the current adjusting member 515. As shown in FIG. The corrosion protector 510 of the fifth embodiment includes a current adjusting member 515 in an electrolyte section 514 .

[0072] Current adjusting member 515 is a film-like or sheet-like member in which a plurality of openings 515a are formed. Current adjusting member 515 preferably has a smaller thickness than electrolyte portion 514 and is flexible enough to fit around the circumferential direction of the cylindrical shape of corrosion protector 510. Moreover, the current adjusting member 515 is preferably formed of a material having lower conductivity than the electrolyte material forming the electrolyte section 514, and is desirably formed of an insulating material. Such current adjusting member 515 may be formed of a resin member such as PET or PC, a paper member, a wooden member, or a metal member.

[0073] In this embodiment, the openings 515a are arranged along two intersecting directions when the current adjustment member 515 is viewed in a plan view, as shown in FIG. 11 . However, the present invention is not limited to this. The openings 515a may be arranged along one or three directions, the arrangement pitch may vary in each direction, or the openings 515a may be arranged randomly. The openings 515a may have a circular shape, an elliptical shape, a polygonal shape, or a combination of these. The arrangement and shape of the openings 515a may be selected and combined as appropriate.

[0074] 10 , the current adjusting member 515 is provided on the surface of the electrolyte part 514 on the anchor bolt 20 side. However, the current adjusting member 515 is not limited to this, and may be located anywhere between the sacrificial anode part 11 and the anchor bolt 20 in the radial direction of the corrosion protector 10 (the direction perpendicular to the axis A). Therefore, the current adjusting member 515 may be located on the surface of the electrolyte part 514 closest to the sacrificial anode part 11, or may be provided inside the electrolyte part 514.

[0075] In this embodiment, the current adjusting member 515 is provided by adhering a sheet-like member made of a gel electrolyte material to the inner circumferential surface of the sacrificial anode portion 11, and then adhering the member to the surface (inner circumferential surface) of the electrolyte portion 514. Alternatively, the current adjusting member 515 may be provided by adhering the sheet-like member made of a gel electrolyte material to one side in advance. The method of providing the current adjusting member 515 to the electrolyte portion 514 may be appropriately selected depending on the viscosity of the electrolyte material of the electrolyte portion 514, the material of the current adjusting member 515, the aperture ratio of the openings 515a, etc.

[0076] By providing such a current adjusting member 515, the amount of movement of metal ions, which are positively charged, moving within the electrolyte section 514 from the sacrificial anode section 11 to the anchor bolt 20 can be adjusted by the opening area (opening ratio) of the opening 515a, and the amount of corrosion current (anticorrosion current when viewed from the anchor bolt 20 side) can be adjusted. The gap S in which the corrosion protector 510 is placed is a narrow space of about a few millimeters, and it is difficult to prolong the anticorrosion effect of the corrosion protector by increasing the volume of the sacrificial anode portion 11. Therefore, by providing such a current adjusting member 515, the amount of corrosion current can be adjusted, and the anticorrosion effect of the corrosion protector 510 can be prolonged.

[0077] The anticorrosion tool 510 of this embodiment is installed in the same manner as the anticorrosion tool 10 of the first embodiment described above. In the present embodiment, as in the first embodiment, the corrosion protector 510 can suppress corrosion of the anchor bolt 20. Furthermore, since the electrolyte section 514 of the corrosion protector 510 is provided with the current adjusting member 515, the corrosion protector 510 can achieve a long-term corrosion prevention effect.

[0078] (Variations) The present invention is not limited to the above-described embodiments, and various modifications and variations are possible, and these are also within the scope of the present invention. (1) In the first, second, and fifth embodiments, examples have been shown in which the corrosion protector has a cylindrical shape, but this is not limiting, and for example, the corrosion protector may have a shape in which a plurality of slits extending in the direction of the axis A are formed in the sacrificial anode portion 11. By adopting such a shape, when the corrosion protector is placed in the gap S, it becomes more flexible than when there are no slits, and the corrosion protector can be easily inserted into the gap S.

[0079] (2) In each embodiment, the electrolyte portion 14 is provided on the bolt side by applying an electrolyte material to the outer peripheral surface of the anchor bolt 20 in order to improve adhesion with the anchor bolt 20 when a corrosion protector is placed in the gap S. However, the electrolyte material may be applied to both the outer peripheral surface of the anchor bolt 20 and the inner peripheral surface of the sacrificial anode portion.

[0080] (3) In each embodiment, the terminal portion is provided at the upper end of the corrosion protector in the direction of axis A, but this is not limiting, and the position in the direction of axis A may be changed as appropriate.

[0081] (4) In each embodiment, contact grease may be applied to the threaded portion between the terminal portion and the anchor bolt 20. By adopting such a configuration, electrical conduction between the terminal portion and the anchor bolt 20 can be stabilized.

[0082] (5) In each embodiment, the anchor bolt 20 is exposed from the concrete structure 40, but this is not limiting and the anchor bolt may be exposed from the ground.

[0083] (6) In each embodiment, the height (dimension in the direction of axis A) of the corrosion protector is equal to or less than the depth of the mounting hole 31, but this is not limiting, and the height of the corrosion protector may be greater than the depth of the mounting hole 31. In such a case, it is preferable to use a washer whose inner diameter is greater than the outer diameter of the corrosion protector 10, so that the height of the corrosion protector can be increased by the thickness of the washer. By adopting such a configuration, the volume of the sacrificial anode portion can be increased, and the period during which the corrosion prevention effect of the corrosion protector is effective can be extended.

[0084] (7) In the second to fifth embodiments, similarly to the first embodiment, it is preferable to provide an insulating layer (not shown) using insulating tape or the like on the outer circumferential surface of the corrosion protector, particularly on the outer circumferential surface of the sacrificial anode portion. This prevents corrosion current from flowing toward the base plate 30, enhancing the effect of the corrosion protector in suppressing corrosion of the anchor bolt 20. Furthermore, an insulating sheet or the aforementioned insulating tape may be attached to the inner circumferential surface of the mounting hole 31 to prevent electrical connection between the base plate 30 and the corrosion protector.

[0085] The present invention is not limited to the above-described embodiments, and the detailed description thereof will be omitted. [Explanation of symbols]

[0086] 10,210,310,410,510 Corrosion prevention equipment 11,311 Sacrificial anode 12,317 Terminal section 13 Holding part 14,314,514 Electrolyte section 215 Porous part 20 anchor bolts 30 base plate 31 Mounting hole S Gap 40 Concrete Structures

Claims

1. A corrosion preventive device that is placed in a gap between an anchor bolt and a base plate in an attachment hole of a base plate of a structure that is fixed by the anchor bolt, a terminal portion that contacts the anchor bolt; a sacrificial anode portion electrically connected to the terminal portion and formed of a material having a higher ionization tendency than a material forming the anchor bolt; an electrolyte portion that contacts the sacrificial anode portion and the anchor bolt with the corrosion protector disposed in the gap and contains an electrolyte material; Corrosion prevention equipment equipped with

2. The electrolyte portion is formed of at least one of a gel electrolyte material formed in a sheet shape and a gel electrolyte material having fluidity. The corrosion protection device according to claim 1.

3. the electrolyte portion is a porous body formed of a material having a higher ionization tendency than a material forming the anchor bolt, and the porous portion holds the electrolyte material in at least some of the pores. The corrosion protection device according to claim 1.

4. It consists of a plurality of parts each having a cylindrical shape, Each of the plurality of members includes the terminal portion, the sacrificial anode portion, and the electrolyte portion, The plurality of members are arranged so as to be in contact with the outer periphery of the anchor bolt, and are fixed by a fixing member that fixes the positions of the plurality of members in the radial direction of the anchor bolt. The corrosion protection device according to claim 1.

5. The terminal portion and the sacrificial anode portion are both cylindrical and axially connected or integrally formed, The terminal portion has a threaded portion on its inner circumferential surface that screws into the anchor bolt. The corrosion protection device according to claim 1.

6. At least the sacrificial anode part is a porous body. The corrosion protection device according to claim 1.

7. The electrolyte section includes a sheet-like or film-like current adjusting member having a plurality of openings formed therein. The corrosion protection device according to claim 1.

8. The anchor bolt is disposed in a mounting hole of a base plate of a structure to be fixed by the anchor bolt; a terminal portion that contacts the anchor bolt; a sacrificial anode portion electrically connected to the terminal portion and formed of a material having a higher ionization tendency than a material forming the anchor bolt; an electrolyte portion in contact with the sacrificial anode portion and the anchor bolt and containing an electrolyte material; A method for installing a corrosion prevention device comprising: a bolt-side electrolyte portion disposing step of disposing a bolt-side electrolyte portion containing an electrolyte material on an outer peripheral surface of the anchor bolt located in the mounting hole; a corrosion protector placement step of placing the corrosion protector in a gap between the anchor bolt and the base plate in the mounting hole with the electrolyte portion integral with the bolt-side electrolyte portion in contact with the anchor bolt; A method for installing corrosion prevention equipment.

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