JP4414256B2 - Galvanic anode device for cathodic protection and method for cathodic protection of metal structure using said device - Google Patents

Description

  The present invention relates to a galvanic anode device that is installed in an underwater part of a metal structure such as a harbor structure and a river structure, and that can easily measure the anticorrosion current generated by the anode, and a metal structure using the galvanic anode device The present invention relates to a method for cathodic protection of objects.

  Mainly aluminum alloy was used as a method to prevent the steel pipe piles and steel sheet piles that make up the foundations of harbor facilities such as piers and revetments, road bridges, and railway bridges from being corroded by seawater and / or river water. The cathodic protection method by the galvanic anode method is widely used.

  Because harbor facilities and bridges are facilities that are used for a long period of 50 years or more, when the galvanic corrosion protection method is used to protect these metal foundations, the life span is generally about 10 to 30 years. An galvanic electrode having a lifetime of 1 mm is used. In recent years, with the enlargement of structures, it may be necessary to attach a large galvanic anode having a service life of 50 years or more.

  When the galvanic corrosion prevention method is used, it is very important for the maintenance and management of the facility to monitor whether or not the galvanic anode generates the anticorrosion current as designed. Since the consumption of the galvanic anode is proportional to the product of the generated current and time (the amount of electricity) according to Faraday's law, the consumption of the galvanic anode is measured by measuring the current generated by the galvanic anode over time. Can be estimated.

  There is no problem if the consumption amount of the galvanic anode is substantially the same as the original anticorrosion design value. However, during long-term anticorrosion, changes in the environment surrounding the structure, such as water temperature, water pollution, and water resistivity, unforeseen deterioration of the coating applied to the structure, and other Factors such as the structural change of the structure itself, such as connection with the structure, may change beyond the initial expectations, and the change may affect the life of the galvanic anode.

  In addition, in large structures and complex structures, the anticorrosion conditions are not uniform throughout the structure, and the galvanic anode at one location of the structure is faster than the anticorrosion design value, and the galvanic anode at another location. In some cases, the consumption rate is slower than the anticorrosion design value.

  For this reason, a method is known in which a shunt resistor is inserted between the galvanic anode and the structure, the core metal of the galvanic anode is separated from the structure, and the anticorrosion current generated by the galvanic anode is measured by the voltage drop method. (For example, refer nonpatent literature 1).

  A specific example of an apparatus for measuring the anticorrosion current generated by the galvanic anode using the voltage drop method is shown in FIG. In the apparatus shown in FIG. 4, a grooved steel 6 is fixed to the metal structure 1, and a cored bar of the grooved steel 6 and the galvanic anode 2 (hereinafter also referred to as an anode cored bar or simply a cored bar) through an electrical insulator 3. ) 21 is fixed with an insulating bolt nut 41. Further, the one anode core 21 and the grooved steel 6 are connected to the terminal 43 and the terminal 44 of the DC current measuring device 5, respectively. There is a shunt resistor in the DC current measuring device 5, and the core wire of the cable 7 is connected to both ends of the shunt resistor, and the cable 7 is led to the ground.

  In addition, a sensing electrode made of the same kind of metal as the metal structure is attached to an underwater metal structure that is electrically protected, and a non-resistance current measuring instrument is connected to the sensing electrode and the metal structure with a lead wire that is insulated. An anti-corrosion current monitor is known which is connected via a cable (see, for example, Patent Document 1).

JP-A-8-283969 Material of Port Engineering Lab. No.475 Electric Corrosion Protection Survey of Port Structures (Part 1) Port Technology Research Institute, Ministry of Transport Issued in March 1984

  However, a shunt resistor is inserted between the galvanic electrode and the metal structure, and the anode core is cut off from the metal structure, and the current generated by the galvanic anode using the voltage drop method ( The above-mentioned method for measuring the corrosion resistance of the metal structure by this current (hereinafter, this current is also referred to as generated current) takes a long time to disconnect the anode core from the metal structure, And the work cost for that is also expensive. In addition, since the DC current measuring device 5 and the cable 7 are integrated in the conventional general generated current measuring device shown in FIG. 4, the core wire of the cable 7 is cut or the shunt resistance is damaged. Even if a defect occurs in a part of the equipment, it is necessary to replace the entire device, and the repair cost is high.

  Further, the cathodic protection current monitor disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 8-283969) measures and monitors the corrosion protection current flowing into the metal structure. It cannot be measured accurately.

  That is, the present invention solves the problems of the prior art, can measure the generated current without detaching the anode core from the structure, and it is necessary to replace the entire apparatus even when a malfunction occurs in a part of the apparatus. The present invention seeks to provide a non-fluidic anode device and a corrosion prevention method using the galvanic anode device.

The galvanic anode device of the present invention is characterized by the structure and configuration of the attachment portion between the galvanic anode and the metal structure.
That is, the galvanic anode device of the present invention is a galvanic anode device used in a method for preventing corrosion of a metal structure,
Using a direct current measuring instrument having a terminal for electrical connection with the metal structure and a terminal for electrical connection with the galvanic anode,
While fixing the core metal of the galvanic anode on the metal structure via an electrical insulator provided with an insertion port of the terminal of the direct current measuring device,
When the terminal is inserted into the insertion port, the terminal for electrically connecting to the metal structure is electrically connected to the metal structure and electrically connected to the metal core The terminal is electrically connected to the core bar, whereby the anticorrosion current can be measured by the DC current measuring device.

  In the galvanic anode device, it is preferable that a current measuring cable is further detachably connected to the direct current measuring device.

  In each of the galvanic anode devices, it is preferable that a data logger for recording a current value generated by the galvanic anode together with a measurement time is further connected to the direct current measuring device.

  When a data logger is further connected to the DC current measuring device, it is preferable that the data logger is stored in a container having a waterproof structure, and the container is disposed in the vicinity of the DC current measuring device.

  In the galvanic anode device according to another aspect of the present invention, in each of the galvanic anode devices, the DC current measuring device is inserted into an insertion port of the electrical insulator provided for inserting a terminal of the DC current measuring device. Instead, the metal structure and the metal core are electrically connected by the conductor by inserting a conductor having the same shape as the terminal of the direct current measuring device. is there.

  When the two or more galvanic anodes are disposed in the underwater portion of the metal structure to perform the galvanic protection of the metal structure, the galvanic protection method of the present invention is the above-described galvanic current as at least one of the galvanic anodes. At least one of the anode devices is used.

  According to another aspect of the present invention, there is provided an electrocorrosion protection method, wherein two or more galvanic anodes are disposed in an underwater portion of a metal structure to perform electrocorrosion protection of the metal structure. When measuring the generated current of the galvanic anode using any one of the galvanic anode devices, a conductor having the same shape as the terminal of the DC current measuring device is removed and the terminal of the DC current measuring device is removed. The generated current is measured by inserting into the insertion port of the electrical insulator.

  The galvanic anode device of the present invention does not require an operation such as cutting the core metal of the anode when measuring the generated current of the anode, and is an electric insulator disposed between the core metal and the metal structure. The current generated at the anode can be measured very easily by inserting the terminal of the direct current measuring device into the insertion slot. Further, when the generated current is not measured, the galvanic anode method can be performed by inserting a conductor having a predetermined terminal into the insertion port of the electric insulator instead of the direct current measuring device. Further, by allowing the current measuring cable to be detachably connected to the DC current measuring device, it is possible to easily exchange the DC current measuring device or the current measuring cable. Further, data for managing the anode life and the like can be easily obtained by connecting a data logger to the current measuring instrument.

  Hereinafter, the present invention will be described more specifically with reference to FIGS. 1 to 3, but the apparatus shown in these drawings schematically shows the apparatus of the present invention in order to explain the present invention. Necessary structures can be appropriately given and / or modified as desired, and the present invention is not limited to those shown in these drawings.

  FIG. 1 is a diagram schematically showing a portion where a galvanic anode device of the present invention is coupled to a metal structure 1. In addition, although the shape of the metal structure 1 is not clearly shown, it is combined with the grooved steel 6 in the same manner as that shown in FIG. FIG. 1 shows only one of the two core bars 21 included in the galvanic anode 2. The configuration of the coupling portion between the other core metal (not shown) and the grooved steel is the same as the configuration of the coupling portion shown on the left side of FIG. The grooved steel 6 is welded to the metal structure 1 and the grooved steel 6 and the cored bar 21 are joined together by an insulating bolt nut 41 via an electrical insulator 3, whereby the galvanic anode 2 is connected to the metal structure. 1 is fixed. The electric insulator 3 is provided with two gaps, a gap 31 and a gap 32. Reference numeral 5 denotes a direct current measuring instrument having a terminal 51 and a terminal 52 on its side surface. The DC current measuring instrument 5 has a receptacle 55, while the cable 7 has a connector shell 56 and a connector cover 72. By connecting the connector shell 56 to the receptacle 55, the DC current measuring instrument 5 and the cable 7 are connected. It is designed to be electrically detachable. Actually, it is preferable that the direct current measuring instrument 5 is placed in water after being connected to the cable 7 in advance. The cable 7 extends to the upper structure portion of the metal structure 1 and is connected to a measuring instrument (not shown).

  In FIG. 1, by inserting the terminals 51 and 52 of the DC current measuring device 5 into the gaps 31 and 32 of the electrical insulator 3, respectively, the terminal 51 contacts and is electrically connected to the core metal 21, and the terminal 52 is The grooved steel 6 is in contact with and electrically connected. In this way, the current generated by the galvanic anode 2 can be measured by the direct current measuring device 5 by electrically connecting the core metal 21, the direct current measuring device 5, and the grooved steel 6. The measured current value is sent to the measuring instrument through the cable 7.

  FIG. 2 shows a partial structure of the galvanic anode device in a mode different from the galvanic anode device shown in FIG. The metal structure 1, the grooved steel 6, the galvanic anode 2, the cored bar 21, and the electrical insulator 3 have the same configuration as the apparatus shown in FIG. However, in the apparatus of FIG. 2, the insulating bolt 42 is disposed so as to penetrate the gaps 31 and 32. Further, by inserting the terminals 53 and 54 of the direct current measuring instrument 5 having a notch having a shape into which the insulating bolt 42 can be inserted at the tip of the terminal into the gaps 31 and 32, respectively, and tightening with the insulating bolt 42 and the nut. The terminal 53 of the direct current measuring instrument 5 can be firmly connected to the core metal 21 and the terminal 54 can be firmly connected to the grooved steel 6.

  In the apparatus shown in FIG. 2, the cable 7 can be connected to the receptacle 55 of the direct current measuring instrument 5 as shown in FIG. 1, or the bolt 65 is used as shown in FIG. A cable having a waterproof structure (also referred to as a data logger built-in container) 60 with a built-in data logger fixed to the side surface of the grooved steel 6, and a cable connected to the data logger built-in container 60 using a receptacle 55 and a connector shell 56 75 can also be detachably connected to the DC current measuring device 5. In this way, the current generated by the galvanic anode 2 can be measured by the DC current measuring device 5, and the obtained current value can be recorded together with the measurement time by the data logger. In the apparatus shown in FIG. 1, the same method as that shown in FIG. 2 can be used to arrange the data logger built-in container 60 and connect the DC current measuring device 5 to it.

  The apparatus shown in FIG. 3 uses a conductor 8 having terminals 81 and 82 having the same shape as the terminals of the DC current measuring instrument 5 instead of the DC current measuring instrument 5 in the apparatus shown in FIG. In FIG. 3, by inserting the terminals 81 and 82 of the conductor 8 into the gaps 31 and 32 of the electrical insulator 3, respectively, the core metal 21 and the terminal 81 are electrically connected, and the groove steel 6 and the terminal 82 are connected. The core metal 21 is electrically connected to the channel steel 6 after all.

  The galvanic anode used in the present invention may be a known one, but is made of a material selected from, for example, an aluminum alloy, a zinc alloy, and a magnesium alloy, and the anode 2 and the core metal 21 are integrally formed. Is common. The insulator 3 may be any material that does not have electrical conductivity. For example, a material selected from polyvinyl chloride resin, acrylic resin, polypropylene resin, polycarbonate resin, ceramics, stone, and bakelite can be used. As the conductor 8 including the terminals 51, 52, 53, and 54 and the terminals 81 and 82 of the current measuring device 5, a material selected from steel, copper, a copper alloy, stainless steel, and the like can be used. As the direct current measuring instrument 5, a known one can be used, for example, a current shunt type. A known data logger can be used. However, the said material etc. are illustrations and you may use materials other than this.

  Normally, when the galvanic anode device is used in the form shown in FIG. 3 to generate a corrosion-proof current from the galvanic anode 2, and it is necessary to measure the generated current of the galvanic anode, the galvanic anode device The electric current 8 can be measured by removing the electric conductor 8 from the electric insulator 3 and inserting the terminals 51 and 52 of the DC current measuring device 5 into the electric insulator 3 as shown in FIG. .

  By using the galvanic anode device configured as described above, the generated current of the galvanic anode can be measured without separating the core metal of the galvanic anode from the metal structure, which makes the work easier and the operation cost. Can be reduced. Furthermore, when a malfunction occurs in a part of the galvanic anode device, only the defective portion can be replaced without replacing the entire device, so that the repair can be facilitated and the cost for that can be reduced. In addition, by using a data logger as described above, the measurement time can be collected as data together with the current generated by the galvanic anode, and data processing over a long period of time can be easily performed by a computer. Can be done accurately.

  In the galvanic anode device shown in FIG. 2, the cable 75 for connecting the DC current measuring device 5 and the data logger built-in container 60 can be shortened. In addition, the stress received from the waves can be reduced, and the damage to the conductor in the cable can be reduced. Since the lifetime of the galvanic anode can be predicted by measuring the current generated by the galvanic anode using the galvanic anode device of the present invention, and the presence or absence of failure of the galvanic anode device can be known. Management of cathodic protection becomes easy. Further, it is usually necessary to use the conductor 8 shown in FIG. 3 and replace the conductor 8 with the DC current measuring device 5 shown in FIG. 1 or 2 when measuring the current generated by the galvanic anode. In this case, the generated current can be easily measured.

  When a metal structure is subjected to electrocorrosion protection, two or more galvanic anode devices can be arranged in the underwater portion of the metal structure to perform galvanic protection by the galvanic anode method. In this case, the galvanic anode device of the present invention described above is used for at least one of the two or more galvanic anode devices, and the galvanic anode device of the present invention is used to generate the galvanic anode as described above. It is preferable to measure the current. In particular, the terminals 81 and 82 of the conductor 8 shown in FIG. 3 are respectively inserted into the gaps 31 and 32 of the electrical insulator 3, and the anticorrosion is performed with the anode core 21 and the grooved steel 6 being electrically connected. At the same time, when measuring the current generated by the galvanic anode, the conductor 8 is removed, and the terminals of the DC current measuring device 5 shown in FIG. It is also possible to measure the generated current at which is generated. By using this method, (1) it is possible to measure the generated current of many galvanic anodes 2 with a small number of DC current measuring instruments 5, and (2) changing the galvanic anode 2 for measuring the generated current as required. Therefore, unlike the conventional method in which the generated current can be easily measured only with the galvanic anode equipped with a direct current measuring instrument from the beginning, the generated current of the desired galvanic anode 2 can be measured at any time. Accordingly, the corrosion prevention of the entire metal structure can be performed more effectively by replacing the electroplating anode 2 and reviewing the number and arrangement of the electroplating anodes 2.

Schematic diagram showing one embodiment of the connecting structure portion of the galvanic anode device and metal structure Schematic diagram showing another embodiment of the connecting structure portion of the galvanic anode device and metal structure The schematic diagram which shows another one aspect | mode of the connection structure part of a galvanic anode apparatus and a metal structure Reference diagram showing a conventional galvanic anode device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Metal structure, 2 ... Current-flow anode, 21 ... Core metal, 3 ... Electrical insulator, 31 and 32 ... Air gap, 41 ... Insulation bolt nut, 42 ... Insulation bolt, 5 ... DC current measuring device, 43, 44 , 51, 52, 53, and 54 ... DC current measuring device terminals, 55 ... Receptacle, 56 ... Coupling shell, 6 ... Channel steel, 60 ... Container with built-in data logger, 65 ... Bolt, 72 ... Shell cover, 7, 75 ... Cable, 8 ... Conductor, 81 and 82 ... Terminals of the conductor

Claims (7)

A galvanic anode device for use in a method for cathodic protection of metal structures,
Using a direct current measuring instrument having a terminal for electrical connection with the metal structure and a terminal for electrical connection with the galvanic anode,
While fixing the core metal of the galvanic anode on the metal structure via an electrical insulator provided with an insertion port of the terminal of the direct current measuring device,
When the terminal is inserted into the insertion port, the terminal for electrically connecting to the metal structure is electrically connected to the metal structure and electrically connected to the metal core The terminal is electrically connected to the metal core, thereby enabling measurement of the anticorrosion current by the DC current measuring device.   The galvanic anode device according to claim 1, wherein a current measuring cable is further detachably connected to the DC current measuring device.   The galvanic anode device according to claim 1 or 2, further comprising a data logger connected to the DC current measuring device for recording a current value generated by the galvanic anode together with a measurement time.   4. The galvanic anode device according to claim 3, wherein the data logger is stored in a container having a waterproof structure, and the container is disposed in the vicinity of the direct current measuring device.   In the galvanic anode device according to any one of claims 1 to 4, in place of the DC current measuring device, an insertion port of the electrical insulator provided for inserting a terminal of the DC current measuring device. A galvanic anode device in which the metal structure and the metal core are electrically connected by the conductor by inserting a conductor having a terminal having the same shape as the terminal of the direct current measuring device. .   When arranging two or more galvanic anodes in an underwater portion of a metal structure and performing the anticorrosion of the metal structure, at least one of the galvanic anodes is according to any one of claims 1 to 5. An anticorrosion method for a metal structure, characterized by using a galvanic anode device. When the two or more galvanic anodes are arranged in the underwater portion of the metal structure to perform the anticorrosion of the metal structure, the galvanic anode device according to claim 5 is used as at least one of the galvanic anodes. When measuring the generated current of the galvanic anode device, the conductor having the same shape as the terminal of the DC current measuring device is removed and the terminal of the DC current measuring device is inserted into the insertion port of the electrical insulator. And measuring the generated current.

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