KR101321939B1 - Cathode protecting system for above water portion in marine structure - Google Patents

Abstract

Disclosed is a negative electrode type system for a negative electrode type of a marine structure divided into an underwater part and an aqueous part. The waterborne cathode system comprises: a sacrificial anode disposed in the subsea portion either adjacent to the marine structure or adjacent to the marine structure; A hygroscopic fibrous layer which pulls the anticorrosive current from the sacrificial anode together with water from the underwater portion to the water phase portion and transfers it to the marine structure; It includes a support layer disposed on the moisture absorbing fiber layer.

Description

Cathode PROTECTING SYSTEM FOR ABOVE WATER PORTION IN MARINE STRUCTURE}

The present invention relates to a cathodic protection system of an offshore structure comprising concrete and / or metal (especially iron), and more particularly, by drawing an anticorrosive current from the sacrificial anode in water by using an absorbent body, iron and And / or a cathodic system for protecting the water phase of marine structures made of concrete from corrosion.

In general, marine structures such as steel structures or concrete structures exposed to the marine environment will cause rapid corrosion due to chlorine ions and dissolved oxygen contained in seawater.

The marine structure is divided into four parts according to the height of the sea level, and the four parts are shown in [Table 1] below.

division Explanation Underwater * Always locked below sea level Tidal * Just above the water
* Areas where seawater immersion and air exposure are repeated due to tidal difference Splash * Just above the tidal basin
* Where seawater or seawater splashes are caused by waves, depending on sea conditions Waiting * Just above the droplets
* Parts exposed to air without direct contact with seawater

In Korea, there is a difference in height between tidal zones depending on sea area and season.

Many techniques have been proposed to protect such offshore structures from corrosion. Typical methods for protecting offshore structures from corrosion include surface treatment techniques such as painting and cathodic protection. Of these, the surface treatment technology such as coating is easily deteriorated when the surface treatment layer such as coating is exposed to poor corrosion environment has a disadvantage that must be periodically repaired with a lot of time and expense.

On the other hand, the cathodic method is a method of suppressing or reducing damage to metal materials by supplying anticorrosive currents to prevent metal corrosion, and if designed and constructed properly, it can guarantee relatively high reliability and long life. Can be. Cathodic methods include externally powered cathode methods and sacrificial cathode cathode methods.

Externally powered method is generally used the cathode system including power supply, rectifier and anode, and the rectifier current is converted from alternating current to direct current by rectifier directly to the reinforcing bar in the concrete structure through the anode. That's the way. In addition, the sacrificial anode method uses a metal that is more corrosive than the rebar in the concrete structure as a sacrificial anode.

Existing external power cathodic system, besides the disadvantage of high price, is not easy to install on site, and is properly maintained through periodic inspection by experts due to operational problems such as frequent component failure and damage to rectifier due to lightning strike. There is a disadvantage that must be given.

The major disadvantage of the conventional sacrificial cathode type cathode is that it is difficult to control the amount of anticorrosive current, so it is difficult to apply to dry areas or areas with too much surface area. Most sacrificial cathode cathodic methods do not have an electrolyte (especially in the case of steel structures) to deliver anticorrosive currents in the intertidal and subtidal zones with the highest corrosion rates, or lack of power (especially in the case of steel structures). Concrete structures), making the method impossible or insufficient.

As an alternative to solve the above problems, a cathode type system has been proposed in which a jacket is put on the tidal and splash stages and the mortar, which serves as an electrolyte, is filled so that the anticorrosive current is reached even in this section. However, such a cathodic system also has to be jacketed and filled with mortar in the field, so the workability is very poor and consequently a very expensive system.

A study of the erosion of marine concrete structures using sacrificial anodes from the Florida Department of Transportation found that the anticorrosive currents from the bulk sacrificial anodes installed under water reached the pier foundation along the water in the concrete. lost.

 However, since the moisture in the concrete decreases and the resistance of the concrete increases as the head moves away from the water surface, the anticorrosive current decreases rapidly, and the sufficient method was performed only near the water surface.

Therefore, the problem to be solved by the present invention is to use the structure of the material that absorbs moisture well, to transfer the anticorrosive current from the sacrificial anode to the water region area farther from the sea surface, the water surface of the marine structure in a larger area It is to provide a system that protects the part from corrosion.

According to an aspect of the present invention, there is provided an aquatic part cathodic system for a cathodic method of an offshore structure divided into an underwater part and an aquatic part, and the aquatic part cathodic method system is adjacent to or adjacent to the marine structure. A sacrificial anode disposed in the underwater portion; A hygroscopic fibrous layer which pulls the anticorrosive current from the sacrificial anode together with water from the underwater portion to the water phase portion and transfers it to the marine structure; It includes a support layer disposed on the moisture absorbing fiber layer.

According to one embodiment, the support layer may comprise a rubber panel. More preferably, the rubber panel and the hygroscopic fibrous layer are combined in advance before being installed in the marine structure to form a hygroscopic composite. The hygroscopic composite may be coupled to the marine structure by anchor bolts. Alternatively, the hygroscopic composite may be coupled to the marine structure by stainless steel bands. It is advantageous to use the anchor bolt when the particular part of the marine structure that is bonded to the hygroscopic composite is planar.

According to one embodiment, the support layer, more preferably, the rubber panel may include a groove pattern for passing through the sea water to the moisture absorbing fiber layer. The groove pattern preferably includes a passage pattern extending in the vertical direction for smooth vertical movement of seawater when the water level rises. In addition, the groove pattern, it is preferable to include a plurality of fresh water patterns arranged long in the vertical direction in order to maintain the seawater that is standing when the water level is lowered. The plurality of freshwater patterns are preferably connected to the passage pattern. In addition, the freshwater pattern preferably includes a concave shape. The concave shape may include a V shape or a chevron shape.

According to one embodiment, an additional sacrificial anode may be further installed on the support layer. The water phase part includes a tidal bag directly above the submerged part and a droplet bag directly above the tidal bag, wherein the support layer and the hygroscopic fiber layer are provided over at least the submerged part, the tidal bag, and the droplet bed. The additional sacrificial anode can be particularly advantageously applied in the case of long tides and droplets.

According to the present invention, by using a hygroscopic composite comprising a hygroscopic fibrous layer and a support layer (more specifically, a rubber panel), the anticorrosive current from the sacrificial anode in the underwater part is transferred to the arbitrary position of the water part away from the sea surface together with the moisture. Thus, it is possible to provide an effect of suppressing corrosion over a large area of the marine structure including the underwater portion and the water phase portion.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view for explaining an experiment used in the validation of a negative electrode system of an offshore part of a marine structure according to the present invention, and a compact concrete specimen used in the experiment.
Figure 2 is a view for explaining the negative electrode system of the water phase of the offshore structure having a structure suitable for practical application according to an embodiment of the present invention.
Figure 3 is a view for explaining a hygroscopic composite suitable for an aqueous phase negative electrode system according to the present invention.
Figure 4 is a view for explaining how the fresh water pattern provided in the hygroscopic complex according to the water level change.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the same reference numerals denote the same elements, and the width, length, thickness, and the like of the elements may be exaggerated for convenience.

1 is a view showing an experiment used for the validation of the negative electrode system of the offshore part of the marine structure according to the present invention and a small concrete specimen (1) used in the experiment.

Referring to FIG. 1, the specimen 1 was manufactured by compressing a hygroscopic fibrous material 3 having a strong characteristic of sucking moisture with respect to the reinforced concrete column 2 by a rubber panel 4. A stainless steel band 5 was used for the attachment of the hygroscopic fibrous material 3 and the rubber panel 4 to the reinforced concrete column 2. The bulk sacrificial anode 6 is coupled to the bottom of the reinforced concrete column 2. When placing the bulk sacrificial anode 6 in the submerged portion A, the specimen 1 and the reinforced concrete column 2 are sequentially submerged from the submerged portion A, the tidal stem B, and the droplets. It is divided into the table C and the waiting section D. The bulk sacrificial anode 6 is electrically connected to the junction box 7 provided above the specimen 1 on the standby part D side by wiring. The hygroscopic fibrous material 3 is submerged in the water with a portion of the lower side positioned in the underwater portion A.

 Experiments using the specimen (1) described above showed that the moisture and the anticorrosive currents from the bulk sacrificial anode (6) rose up along the specimen (1) in a hygroscopic fibrous material, to which the specimen (1) would reach a much higher surface area. It could be confirmed that the way.

Therefore, if water is supplied in any form to the concrete surface or the steel structure surface of the tidal zone B and the droplet stage C exposed to the atmosphere, the anticorrosive current emitted from the bulk sacrificial anode 6 installed in the water rises upward. It was concluded that the tidal zone (B) and the droplet zone (C) could be sufficiently protected.

Figure 2 shows a negative electrode system of the offshore part of the marine structure according to a preferred embodiment of the present invention, the system shown in Figure 2 includes a structure suitable for construction by easily applying the concept of the invention described above to the field do.

Referring to FIG. 2, an offshore structure 20 including reinforcing bars 22 inside concrete 21 is shown. Of course, the present invention can also be applied to the cathode method of the marine structure made of steel only without concrete.

As shown in FIG. 2, the cathodic system according to the present embodiment includes a hygroscopic fiber layer 13 and a rubber panel 14 as a support layer. In order to be easily applied to the field, the hygroscopic fiber layer 13 and the rubber panel 14 is composed of a single hygroscopic composite 10 by being bonded in advance in the land. The hygroscopic fibrous layer 13 is made of a hygroscopic fibrous material having a strong property of sucking moisture. In addition, the rubber panel 14 is preferably made of a rubber material having a property that does not deteriorate in ultraviolet and marine environments. It is also conceivable to substitute the rubber panel 14 with other reinforcing or supporting materials.

In the present embodiment, the anchor bolt 25 is used as a means for coupling the hygroscopic composite 10 to the marine structure 20. The anchor bolt 25 is fastened to the marine structure 20 through the moisture absorption composite 10. The anchor bolt 25 is particularly advantageous when a particular portion of the offshore structure 10 coupled with the hygroscopic composite 10 is planar. On the other hand, in the case where the portion to be combined with the hygroscopic composite 10 has a three-dimensional shape of a pile or column, it is advantageous to bond the hygroscopic composite 10 to the marine structure 20 using a stainless steel band as described above. Do.

As described above, the sacrificial anode 60 is disposed in the water portion below the sea level, and the regenerative anode 60 is a positive terminal in the junction box 70 installed on the upper portion of the marine structure 10 by wiring. Connected with. As shown, the anticorrosive current indicated by '+ I' rises along the hygroscopic fibrous layer 13 as moisture is absorbed by the hygroscopic fibrous layer 13 of the hygroscopic composite 10 and rises upward. In this process, the anticorrosive current flows to the metal in the offshore structure 20 that becomes the cathode, for example, the rebar 22. The anticorrosive current passing through the rebar 22 in the offshore structure 20 flows to the junction box 70. In the case of offshore structures consisting only of steel or steel without concrete, the anticorrosive current passes through the steel or steel.

Since the hygroscopic composite 10 is installed over the water phase portion including the tidal band B (see FIG. 1) and the droplet stage C (see FIG. 1) immediately above, the anticorrosive current from the sacrificial anode 60 is provided. Is supplied not only to the underwater portion (A; see FIG. 1) of the offshore structure 20 but also to the water phase, thus almost entirely offshore structure 20.

Due to the high tide and the ebb tide, the sea level in contact with offshore structures is constantly changing. In this case, the sea level is increased at the full water level, so that the anticorrosive current can reach the target height. However, at the low water level, the height of the anticorrosive current is lowered compared to the full water level because the sea level is lowered. The most desirable cathodic system is to maintain a constant anticorrosive current at all times regardless of changes in sea level.

3 shows a hygroscopic composite having a suitable structure capable of supplying a constant anticorrosive current to the water phase regardless of changes in sea level.

Referring to FIG. 3, the hygroscopic composite 10 has a groove pattern 141 for continuously supplying water to an upper portion of the water portion (A; see FIG. 1), in particular, the tidal band B and the droplet stand C. , 142). The groove pattern includes the passage pattern 141 formed in the vertical direction and the freshwater patterns 142 longly arranged in the vertical direction. The freshwater patterns 142 are connected to the passage patterns 141. In the present exemplary embodiment, the plurality of freshwater patterns 142 arranged in the vertical direction are connected to each of the two passage patterns 141 between two adjacent passage patterns 141.

The groove patterns 141 and 142 are formed to a position in contact with the surface of the hygroscopic fibrous layer 13 to expose the hygroscopic fibrous layer 13. Sea level rise due to the change of the water level of the groove patterns 141 and 142 allows the seawater to directly reach the hygroscopic fibrous layer 13 through the groove pattern 142 at a higher height. The seawater raised in the vertical direction through the passage pattern 141 accumulates in the freshwater pattern 142. Thus, even if the water level decreases, the seawater accumulates in the freshwater pattern 142.

In the present embodiment, each of the freshwater patterns 142 has a concave shape upwards, more specifically, a V shape or a chevron shape concave upwards. This shape helps the freshwater patterns 142 better with the ability to keep and keep seawater standing. Even if the water level is lowered, the seawater remains in the freshwater pattern 142 and is continuously supplied through the hygroscopic fibrous layer 13 to the concrete or steel structure surface of the marine structure 20 (see FIG. 2) until the next high tide. Can be.

4 is a view for explaining the action of storing the fresh water of the fresh water patterns 142 arranged in the vertical direction when the ebb, high tide is repeated from the lowest water level after construction.

Referring to FIG. 4, when the water level of the submerged portion A rises to the tidal band B, and further to the splash band C by changing from the low tide to the high tide, the seawater is formed in the freshwater pattern formed in the rubber panel 14 ( 142) go up to fill in sequence. Even when the water level is lowered from the high tide to the low tide, the seawater accumulated in the fresh water patterns 142 is maintained. The seawater accumulated in each of the freshwater patterns 142 continuously supplies water to the fiber layer 13, and thus, the anticorrosive current from the sacrificial anode (not shown) in the water also enters the marine structure through the hygroscopic fiber layer 13. Delivered. That is, the anticorrosive current raised from the hygroscopic fibrous layer 13 in the underwater sacrificial anode can be spread evenly on the concrete surface of the tidal and splash zones or the surface of the steel structure.

In FIG. 4, the freshwater pattern 142 denoted by the dot hatch represents a state in which the seawater is stuck, and the freshwater pattern 142 displayed without the hatch represents an empty space in which the seawater is not accumulated.

If the splash and / or tidal zones are too long, it may be assumed that the anticorrosive current coming from the underwater sacrificial anode is not enough. In this case, as shown in FIG. Specifically, an additional small sacrificial anode 60 'may be further installed on the specially manufactured rubber panel 14.

A: Underwater B: Tide
C: Splash Stand D: Waiting Area
6, 60: sacrificial anodes 20: offshore structures
21: Concrete 22: Reinforcing Bars
10: Hygroscopic Composite 13: Fibrous Layer
14: rubber panel 141: passage pattern
142: freshwater patterns

Claims (12)

It is a system for the cathode method of offshore structure divided into underwater part and water part,
A sacrificial anode disposed in said subsea portion at or adjacent said marine structure;
A hygroscopic fiber layer which pulls the anticorrosive current from the sacrificial anode together with water to the offshore structure from the water portion to the water phase portion; And
Including a support layer disposed on the moisture absorbing fiber layer,
The support layer is a negative electrode system of the water phase of the offshore structure, characterized in that it comprises a groove pattern for passing through the sea water to the moisture absorbing fiber layer. The method of claim 1, wherein the support layer is a negative electrode system of the water phase of the offshore structure, characterized in that it comprises a rubber panel. The method of claim 2, wherein the rubber panel and the moisture absorbing fibrous layer is combined beforehand to be installed in the marine structure to form a moisture absorbing composite, characterized in that the water system of the offshore part of the offshore structure. The negative electrode system of claim 2, wherein the hygroscopic composite is coupled to the marine structure by anchor bolts. The negative electrode system of the waterborne part of the marine structure of claim 2, wherein the hygroscopic composite is coupled to the marine structure by a stainless steel band. delete The negative electrode system of claim 1, wherein the groove pattern includes a passage pattern extending vertically for smooth vertical movement of seawater when the water level rises. The system of claim 1, wherein the groove pattern includes a plurality of freshwater patterns arranged in a vertical direction to maintain the decayed seawater even when the water level goes down. . The negative electrode system of claim 8, wherein the freshwater pattern comprises a concave shape upward. The method of claim 1, wherein the groove pattern, the passage pattern is formed long in the vertical direction for smooth vertical movement of the sea water when the water level rises, and long in the vertical direction in order to maintain the decayed seawater even when the water level goes down And an array of a plurality of freshwater patterns, wherein the plurality of freshwater patterns are connected to the passage pattern. The waterborne cathode system according to any one of claims 1 to 5 and 7 to 10, wherein an additional sacrificial anode is further provided in the support layer. The method according to any one of claims 1 to 5, 7 and 10, wherein the water phase part comprises a tidal band directly above the submerged part and a droplet band directly above the tidal basin, wherein the support layer and the hygroscopic fibrous layer are at least A water system negative electrode system of the offshore structure, characterized in that installed over the underwater portion, the tidal belt and the droplets.

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