JPH0372160B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a galvanic anode for cathodic protection of submarine pipes, steel pipe piles, etc., and in particular, a method for installing a galvanic anode for cathodic protection of submarine pipes and river bottom pipes. It is related to.

[Conventional technology]

The conventional method for installing galvanic anodes for cathodic protection on rolled structures such as concrete and mortar, such as submarine pipes and river bottom pipes, is as follows:
The following were common.

(1) As shown in Fig. 2, after laying the submarine pipe 1, attach the terminal 3 to an appropriate location on land, start up the lead wire 4a, and connect it to the galvanic anode 4. In the figure, 2 indicates a coating made of concrete or mortar, and 5 indicates the sea surface.

(2) As shown in Figure 3, before laying the submarine pipe 1, a galvanic anode 4 having a thickness equivalent to the thickness of the coating 2 made of concrete or mortar is used.
Method of welding directly to submarine pipe 1 (bracelet method).

In the figure, 6 indicates reinforcement embedded within the coating 2.

(3) As shown in Figure 4, after laying the submarine pipe 1,
A method of welding the terminal 3 to the sea at a certain interval with respect to the extension of the piping, raising the lead wire 4a and connecting it to the current anode 4.

[Problem that the invention seeks to solve]

The conventional method has the following problems.

(1) In the method shown in Figure 2, electricity is applied from a limited location on land, so if the area to be protected against corrosion is large (in this example, submarine pipe 1),
The galvanic anode 4 may be insufficient in its ability, and its anticorrosion effect may be significantly degraded.

(2) Although the method shown in Fig. 3 poses no problem in terms of corrosion protection as a galvanic anode method for the submarine pipe 1, the coating is divided due to the insertion of the galvanic anode 4.
Furthermore, this results in the continuity of the reinforcement 6 being broken, which may cause problems in terms of strength in structures where the reinforcement is a strength factor.

(3) The method shown in Figure 4 can solve the problem in the case of Figure 2, but since the terminal 3 is installed underwater, the coating 2 such as concrete or mortar must be peeled off, and the construction is difficult. It is. Furthermore, repair becomes impossible. As a solution to this problem, it may be possible to have the terminal 3 protrude outside the coating 2 of the submarine pipe 1 while it is on land. It is difficult to implement as it will cause damage.

[Means for solving problems]

The present invention has been made to solve these problems, and includes terminals each having a plurality of insulated lead wires each having a terminal at the tip attached at regular intervals to a structure before installation. The lead wires are guided through between the reinforcing bars of the coating material to the surface of the coating material, and the terminals at the tips of the lead wires are protected with a thin layer of coating material. After the structure is installed, one terminal of each terminal is placed underwater. The present invention provides a method for attaching a galvanic anode for cathodic protection, in which the coating is exposed by scraping off the coating, and the galvanic anode is connected to the galvanic anode.

[Effect]

When pulling out the rollers for laying a structure, the terminals of the lead wires from the terminals are protected by the coating material and there is nothing protruding, so the structure can be moved safely without damage. I can do it. Moreover, after installation,
By slightly scraping the coating material, the terminals are exposed and the galvanic anode can be easily attached.

Furthermore, since the positive electrodes at this time are attached evenly over the entire area of the structure to be protected against corrosion, the anticorrosion effect can be extremely enhanced.

〔Example〕

FIG. 1 shows an embodiment of the present invention, in which A is a side view and B is a cross-sectional view. In the figure, a terminal 3 is welded to the outer peripheral surface of a submarine pipe 1.
A plurality of insulated lead wires 3a are wired from the terminal 3 in the outer circumferential direction passing between the reinforcing bars 6. Each lead wire 3a has a terminal 7 near the surface of the coating material 2, and the lead wire 4a from the galvanic anode 4 is connected to one of the plurality of terminals 7 arranged in the circumferential direction while being buried in the coating material 2. is connected.

Next, this effect will be explained.

Before laying, terminals 3 are welded at regular intervals to the submarine pipe 1 on land, and a plurality of terminals 7 guided from the terminals 3 by lead wires 3a are arranged in the circumferential direction of the submarine pipe 1, Provided near the surface of the coating material 2. After this, the coating will be applied to the entire surface and it will be pulled into the seabed and laid. In this way, since the terminals 7 are protected by the coating material 2, they are not damaged in any way and are arranged at regular intervals in the length direction of the submarine pipe 1. Thereafter, among the plurality of terminals 7 arranged in the circumferential direction, a terminal 7 suitable for attaching the galvanic anode 4 is selected and the coating 2 on the surface thereof is scraped off, and the terminal 7 is guided from the galvanic anode 4 to the exposed terminal 7. Connect the lead wire 4a. By doing this,
Galvanic anodes 4 can be installed on the submarine pipe 1 laid in the sea at regular intervals and on average over the anti-corrosion area.

〔Effect of the invention〕

According to the present invention, since the terminals led from the terminals are arranged in advance near the coating surface, it is possible to install the cable without any obstruction to the structure, and it is also possible to easily attach the anode after the cable is installed. Not only is this possible, but it can also be arranged evenly over the entire surface to be protected against corrosion, so an effect of increasing corrosion protection efficiency can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an embodiment of the present invention, A is a side view, B is a cross-sectional view, and FIGS. 2 to 4 are schematic diagrams of a conventional example. 1: submarine pipe, 2: coating material, 3: terminal, 4: galvanic anode, 6: reinforcement, 7: terminal.

Claims (1)

[Claims] 1 The structure before installation has a terminal at the tip,
Terminals each having a plurality of insulated lead wires are installed at regular intervals, the lead wires are guided through between the reinforcements of the coating material to the surface of the coating material, and the terminals at the tips of the lead wires are protected with a thin coating material, A method for installing a galvanic anode for cathodic protection, characterized in that, after a structure is installed, one of the plurality of terminals of each terminal is exposed by scraping the coating material and connected to the galvanic anode in water. .