Anti-corrosion device

Abstract

To provide a corrosion prevention device capable of changing magnitude of corrosion prevention current as necessary, and a method for operating a corrosion prevention device.SOLUTION: A corrosion prevention device 100 that is provided on a marine vessel having a hull 1 having conductivity, and a propeller 41 that is supported on the hull and is formed of a material having a higher potential than that of a material forming the hull includes: an insulator 2 provided on the outer surface of the hull; a sacrificial anode mounted on the hull through the insulator; a first variable resistor R1 provided between the sacrificial anode and the hull; and a second variable resistor R2 provided between the propeller and the hull.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to an anticorrosion device. Place

Background Art

[0002] When a ship is sailing in seawater, it is known that a battery is formed between the hull mainly made of iron and the propeller made of a copper alloy through seawater. As a result, the propeller made of a copper alloy with a lower potential than iron becomes the anode, and corrosion progresses. In order to prevent such corrosion, a technique of providing a sacrificial anode on the hull is widely used (see, for example, Patent Document 1 below). A sacrificial anode is an electrode made of a metal with a lower potential than iron, such as zinc. Since its potential is lower than that of iron, the sacrificial anode becomes the anode instead of the hull, and a corrosion prevention current is generated between the sacrificial anode and the propeller. It is thus said that corrosion of the propeller can be prevented.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in recent years, a defense device has been developed that detects the presence of a ship by detecting an underwater electric potential (UEP) caused by the above corrosion prevention current. Therefore, the demand for a technology capable of changing the magnitude of the corrosion prevention current as needed is increasing.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide an anticorrosion device capable of changing the magnitude of the corrosion prevention current as needed. Place

Means for Solving the Problems

[0006] In order to solve the above problems, a corrosion prevention device according to the present disclosure is a corrosion prevention device provided on a ship having an electrically conductive hull and a propeller supported by the hull and formed of a material having a higher potential than the material forming the hull, and includes an insulator provided on an outer surface of the hull, a sacrificial anode attached to the hull via the insulator, a first wiring for electrically connecting the hull and the propeller, a second wiring provided independently of the first wiring for electrically connecting the hull and the sacrificial anode, a first variable resistor provided on the second wiring, and a second variable resistor provided on the first wiring. Inside the hull, It does not include a power supply for supplying power to the first wiring and the second wiring. Power supply A corrosion prevention device according to the present disclosure is a corrosion prevention device provided on a ship having a conductive hull and a propeller supported by the hull and formed of a material having a higher potential than the material forming the hull, and includes an insulator provided on an outer surface of the hull, a sacrificial anode attached to the hull via the insulator, a first variable resistor provided between the sacrificial anode and the hull, a second variable resistor provided between the propeller and the hull, a sensor unit provided on the outer surface of the hull for detecting an underwater electric field, and a control unit for changing a resistance value of at least one of the first variable resistor and the second variable resistor based on an input from the sensor unit.

Advantages of the Invention

[0009] According to the present disclosure, it is possible to provide a corrosion prevention device capable of changing the magnitude of a corrosion prevention current as needed. Place

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0011] <First Embodiment> (Configuration of Ship) Hereinafter, the anticorrosion device 100 according to the first embodiment of the present disclosure and its operation method will be described with reference to FIGS. 1 and 2. The anticorrosion device 100 is a device for performing anticorrosion on each part by being provided on the ship S. As shown in FIG. 1, the ship S includes a hull 1, a propeller 4, and the anticorrosion device 100.

[0012] The hull 1 is formed of a conductive metal material. As an example, the hull 1 is formed of iron, and a coating film is provided on its surface. FIG. 1 shows a state in which the lower part of the hull 1 is submerged in seawater. That is, the outer surface 1B of the hull 1 is exposed to seawater.

[0013] The propeller 4 is provided behind the hull 1 and is a device for applying a propulsive force to the hull 1. The propeller 4 has a propeller main body 41, a shaft 42, a grounding part 43, and a bearing 5. The propeller main body 41 has a plurality of blades. The shaft 42 is in the shape of a rod extending along the central axis of the propeller main body 41. The shaft 42 is supported by the hull 1 in a rotatable state around the central axis via the bearing 5.

[0014] A grounding part 43 is provided on a part of the shaft 42 inside the hull 1. The grounding part 43 is provided to electrically connect (ground) the hull 1 and the propeller 4. Specifically, the grounding part 43 and the hull 1 are electrically connected through the first wiring L1.

[0015] Further, the propeller 4 is formed of a copper alloy as an example. That is, the propeller 4 has a higher potential than the hull 1 formed of iron described above.

[0016] (Configuration of the corrosion prevention device) The corrosion prevention device 100 has an insulator 2, a sacrificial anode 3, and a variable resistor R. The insulator 2 is fixed to the outer surface 1B of the hull 1. As the insulator 2, a resin material such as rubber is preferably used. The sacrificial anode 3 is attached to this insulator 2. That is, the sacrificial anode 3 is fixed to the outer surface 1B of the hull 1 via the insulator 2.

[0017] The sacrificial anode 3 is formed of a metal material having a lower potential than iron, such as zinc for example. These insulator 2 and sacrificial anode 3 are provided in the vicinity of the propeller 4 on the outer surface 1B of the hull 1.

[0018] The variable resistor R is a resistor capable of freely changing its resistance value. The sacrificial anode 3 and the hull 1 are electrically connected by a second wiring L2. The variable resistor R is provided on this second wiring L2. The corrosion prevention device 100 is configured as described above, and the configuration itself for generating a corrosion prevention current does not include an external power source for supplying power from the outside. However, an auxiliary power source for automatically operating the variable resistor R and the like may be provided.

[0019] Next, the operation of the corrosion prevention device 100 and the operation method of the corrosion prevention device 100 will be described. When the ship S is performing normal navigation, in the corrosion prevention device 100, the metal species with the lowest potential becomes the anode to form a battery circuit. In the example of FIG. 1, the sacrificial anode 3 formed of zinc or the like with the lowest potential becomes the anode, and the propeller 4 formed of a copper alloy having a higher potential than zinc becomes the cathode.

[0020] As a result, the ground portion 43 of the propeller 4, the first wiring L1, and the hull 1 are electrically connected through the seawater between the sacrificial anode 3 and the propeller 4. Further, the hull 1 and the sacrificial anode 3 are electrically connected via the second wiring L2. When such a battery circuit is formed, a corrosion prevention current A1 is generated between the sacrificial anode 3 and the propeller 4. Thereby, it becomes possible to suppress the corrosion of the propeller 4.

[0021] Furthermore, a circuit is also formed from the sacrificial anode 3 through the seawater to the hull 1. In this circuit, due to the resistance of the coating film provided on the outer surface 1B of the hull 1, a corrosion prevention current A2 smaller than the above corrosion prevention current A1 is formed.

[0022] Here, in recent years, a defense device has been developed that detects the presence of the ship S by detecting the above corrosion prevention current A1. Therefore, the demand for a technology capable of changing the magnitude of the corrosion prevention current A1 as needed is increasing.

[0023] Therefore, in the present embodiment, a variable resistor R is provided on the second wiring L2. As shown in FIG. 2, the operation method of the anticorrosion device 100 includes a step S1 of changing the resistance value of the variable resistor R, a step S2 of changing the corrosion prevention current, and a step S3 of changing the magnitude of the underwater electric field. By changing the resistance value of the variable resistor R in step S1, the magnitude of the current flowing through the above-described battery circuit, that is, the current (corrosion prevention current A1) flowing between the sacrificial anode 3 and the propeller 4 changes.

[0024] More specifically, by adjusting the resistance value of the variable resistor R in the increasing direction, the magnitude of the corrosion prevention current A1 can be reduced. On the other hand, to increase the corrosion prevention current A1 again, the resistance value of the variable resistor R may be adjusted in the decreasing direction. Specifically, the resistance value may be set to 0 Ω. Thus, according to the above configuration, it is possible to control the magnitude of the underwater electric field formed by the corrosion prevention current A1 as needed. Further, in the above configuration, the magnitude of the underwater electric field can be controlled without receiving power supply from an external power source. Note that the above insulator 2 is provided to prevent the corrosion prevention current A1 from flowing directly from the sacrificial anode 3 to the hull 1 without passing through the variable resistor R.

[0025] The first embodiment of the present disclosure has been described above. Note that various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure. For example, in the above first embodiment, an example in which zinc is used as the sacrificial anode 3 has been described. However, as the sacrificial anode 3, any metal having a lower potential than copper, such as aluminum, magnesium, iron, etc., in addition to zinc, can be preferably used. Further, as trace elements thereof, aluminum, zinc, cadmium, magnesium, indium, titanium, iron, tin, manganese, etc. may be included.

[0026] <Second Embodiment> Next, a second embodiment of the present disclosure will be described with reference to FIG. 3. Note that the same components as those in the above first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. As shown in FIG. 3, in the present embodiment, in addition to the first variable resistor R1 provided on the second wiring L2 described above, a second variable resistor R2 is provided on the first wiring L1. The second variable resistor R2 is also a resistor capable of freely changing its resistance value, similar to the first variable resistor R1.

[0027] Here, as shown as the deteriorated portion P in FIG. 3, when the coating film peels off on the outer surface 1B of the hull 1 or the chemical structure of the coating film changes over time, the resistance value of the coating film at the deteriorated portion P may become small.

[0028] In this case, when the corrosion prevention device 100 according to the first embodiment is in operation, the hull 1 of the deteriorated part P may become the anode, and the macrocell current A3 between the hull 1 and the propeller 4 may increase. Specifically, with the deteriorated part P (hull 1) as the anode, a battery circuit that reaches the hull 1 through seawater, the propeller 4, and the first wiring L1 becomes dominant, generating the macrocell current A3. In particular, when the deteriorated part P is significantly separated from the propeller 4, there is a risk that the underwater electric field in the distance may increase due to an increase in the dipole moment.

[0029] Therefore, in this embodiment, a second variable resistor R2 is also provided on the first wiring L1. According to the above configuration, first, by changing the resistance value of the first variable resistor R1, the magnitude of the current (corrosion prevention current A1) flowing between the sacrificial anode 3 and the propeller 4 can be changed. Also, by changing the resistance value of the second variable resistor R2, the magnitude of the current (macrocell current A3) between the propeller 4 and the hull 1 can be changed.

[0030] More specifically, by adjusting the resistance value of the first variable resistor R1 in the increasing direction, the magnitude of the corrosion prevention current A1 can be decreased. On the other hand, to increase the corrosion prevention current A1 again, the resistance value of the variable resistor R can be adjusted in the decreasing direction. Specifically, the resistance value can be set to 0Ω. Similarly, by adjusting the resistance value of the second variable resistor R2 in the increasing direction, the magnitude of the macrocell current A3 can be decreased. In this way, it becomes possible to control the magnitude of the underwater electric field formed by the corrosion prevention current A1 and the macrocell current A3 as needed. Thereby, it becomes possible to control the magnitude of the underwater electric field as needed.

[0031] The second embodiment of the present disclosure has been described above. Note that various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure.

[0032] <Third Embodiment> Next, a third embodiment of the present disclosure will be described with reference to FIG. 4. Note that the same components as those in the above embodiments are denoted by the same reference numerals, and detailed descriptions thereof are omitted. As shown in FIG. 4, the anticorrosion device 100 according to the present embodiment further includes sensor units S1 and S2, an input unit 70, an underwater electric field distribution prediction unit 80, and a control unit 90 in addition to the configuration described in the second embodiment.

[0033] The sensor units S1 and S2 are devices provided on the outer surface 1B of the hull 1 for measuring the potential (underwater electric field) in seawater. Specifically, the potential measured by one of the sensor units S1 is used as a reference potential, and the potential measured by the other sensor unit S2 is detected as an actual value. Therefore, it is desirable to provide not only one but a plurality of sensor units S2. Note that in FIG. 4, only one sensor unit S2 is shown for simplicity of illustration.

[0034] The potential measured by the sensor units S1 and S2 is sent to the input unit 70 as an electrical signal. The input unit 70 transmits these measured values to the underwater electric field distribution prediction unit 80. The underwater electric field distribution prediction unit 80 predicts the distribution of the underwater electric field from the vicinity of the outer surface 1B of the hull 1 to a distance from the periphery of the hull 1 based on the input plurality of measurement results. This distribution is sent to the control unit 90 as an electrical signal. The control unit 90 changes the resistance value of at least one of the first variable resistor R1 and the second variable resistor R2 based on the distribution of the underwater electric field input from the underwater electric field distribution prediction unit 80.

[0035] According to the above configuration, based on the magnitude of the actual underwater electric field detected by the sensor units S1 and S2, the control unit 90 changes the resistance value of at least one of the first variable resistor R1 and the second variable resistor R2. Thereby, the magnitude of the underwater electric field generated by the anticorrosion current A1 or the macrocell current A3 can be controlled more freely and precisely.

[0036] The above has described the third embodiment of the present disclosure. Note that various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure. For example, the configurations of the sensor units S1 and S2 are not limited to the above. As another example, it is also possible to adopt a configuration in which sensor elements are installed at a plurality of locations on the hull and the potential difference of each part is measured when one of them is used as a reference potential.

[0037] <Fourth Embodiment> Next, the fourth embodiment of the present disclosure will be described with reference to FIG. 5. Note that the same reference numerals are given to the same configurations as those in the above embodiments, and detailed descriptions thereof are omitted. As shown in FIG. 5, the anticorrosion device 100 according to the present embodiment further includes a first ammeter M1 and a second ammeter M2 in addition to the configuration described in the above third embodiment.

[0038] The first ammeter M1 is provided on the second wiring L2 on the sacrificial anode 3 side rather than the first resistor R1. The first ammeter M1 measures the magnitude of the current flowing through the second wiring L2 and sends it to the control unit 90 as an electrical signal. The second ammeter M2 is provided on the first wiring L1 on the propeller 4 side rather than the second resistor R2. The second ammeter M2 measures the magnitude of the current flowing through the first wiring L1 and sends it to the control unit 90 as an electrical signal.

[0039] The control unit 90 changes the resistance value of at least one of the first variable resistor R1 and the second variable resistor R2 based on the magnitude of the current flowing through these first wiring L1 and second wiring L2 in addition to the underwater electric field distribution information by the sensor units S1 and S2 described in the above third embodiment. That is, the magnitudes of the anticorrosion current A1 and the macrocell current A3 generated at a certain point in time are fed back to the control unit 90 as electrical signals. The control unit 90 performs feedback control based on this electrical signal to control the magnitudes of the anticorrosion current A1 and the macrocell current A3.

[0040] Thus, according to the above configuration, based on the actual current values measured by the first ammeter M1 and the second ammeter M2, the control unit 90 changes the resistance value of at least one of the first variable resistor R1 and the second variable resistor R2. As a result, the magnitude of the corrosion current A1 or the macrocell current A3 is fed back to the control unit 90, and the control unit 90 can further freely and precisely control the magnitude of the underwater electric field.

[0041] The above is the description of the fourth embodiment of the present disclosure. It should be noted that various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure.

[0042] <Supplementary Note> The corrosion prevention device 100 described in each embodiment and the operation method of the corrosion prevention device 100 are understood as follows, for example.

[0043] (1) The corrosion prevention device 100 according to the first aspect is a corrosion prevention device 100 provided on a ship S having a conductive hull 1 and a propeller 4 supported by the hull 1 and formed of a material having a higher potential than the material forming the hull 1, including an insulator 2 provided on the outer surface 1B of the hull 1, a sacrificial anode 3 attached to the hull 1 via the insulator 2, a first variable resistor R1 provided between the sacrificial anode 3 and the hull 1, and a second variable resistor R2 provided between the propeller 4 and the hull 1.

[0044] According to the above configuration, by changing the resistance value of the first variable resistor R1, the magnitude of the current (corrosion current A1) flowing between the sacrificial anode 3 and the propeller 4 can be changed. Also, by changing the resistance value of the second variable resistor R2, the magnitude of the current (macrocell current A3) between the propeller 4 and the hull 1 can be changed. Thereby, it becomes possible to control the magnitude of the underwater electric field as needed.

[0045] (2) The anticorrosion device 100 according to the second aspect is provided on the outer surface 1B of the hull 1, and includes sensor units S1 and S2 that detect an underwater electric field, and a control unit 90 that changes the resistance value of at least one of the first variable resistor R1 and the second variable resistor R2 based on an input from the sensor units S1 and S2.

[0046] According to the above configuration, based on the magnitude of the actual underwater electric field detected by the sensor units S1 and S2, the control unit 90 changes the resistance value of at least one of the first variable resistor R1 and the second variable resistor R2. Thereby, the magnitude of the underwater electric field can be controlled more freely and precisely.

[0047] (3) The anticorrosion device 100 according to the third aspect further includes a first ammeter M1 provided between the sacrificial anode 3 and the first variable resistor R1, and a second ammeter M2 provided between the propeller 4 and the second variable resistor R2, and the control unit 90 is configured to change the resistance value of at least one of the first variable resistor R1 and the second variable resistor R2 based on the current values measured by the first ammeter M1 and the second ammeter M2.

[0048] According to the above configuration, based on the actual current values measured by the first ammeter M1 and the second ammeter M2, the control unit 90 changes the resistance value of at least one of the first variable resistor R1 and the second variable resistor R2. As a result, the magnitude of the anticorrosion current A1 or the macrocell current A3 is fed back to the control unit 90, and the control unit 90 can control the magnitude of the underwater electric field more freely and precisely.

[0049] (4) The operation method of the corrosion prevention device 100 according to the fourth aspect is a corrosion prevention device 100 provided on a ship S having a conductive hull 1 and a propeller 4 supported by the hull 1 and formed of a material having a higher potential than the material forming the hull 1. The method includes an insulator 2 provided on the outer surface of the hull 1, a sacrificial anode 3 attached to the hull S via the insulator 2, and a variable resistor R provided between the sacrificial anode 3 and the hull 1. The method includes a step S1 of reducing the current flowing between the sacrificial anode 3 and the propeller 4 by changing the resistance value of the variable resistor R.

[0050] According to the above method, by changing the resistance value of the variable resistor R, the magnitude of the current (corrosion prevention current A1) flowing between the sacrificial anode 3 and the propeller 4 can be changed. Thereby, it becomes possible to control the magnitude of the underwater electric field as needed.

[0051] (5) The corrosion prevention device 100 according to the fifth aspect is a corrosion prevention device 100 provided on a ship S having a conductive hull 1 and a propeller 4 supported by the hull 1 and formed of a material having a higher potential than the material forming the hull 1. The device includes an insulator 2 provided on the outer surface 1B of the hull 1, a sacrificial anode 3 attached to the hull 1 via the insulator 2, and a variable resistor R provided between the sacrificial anode 3 and the hull 1, which can change the current value flowing between the sacrificial anode 3 and the hull 1 when there is no external power supply.

[0052] According to the above configuration, by changing the resistance value of the variable resistor R, the magnitude of the current (corrosion prevention current A1) flowing between the sacrificial anode 3 and the propeller 4 can be changed. Thereby, it becomes possible to control the magnitude of the underwater electric field as needed.

Explanation of symbols

[0053] 100 Corrosion prevention device 1 Hull 1B Outer surface 2 Insulator 3 Sacrificial Anode 4 Propeller 5 Bearing 41 Propeller Body 42 Shaft 43 Grounding Part 70 Input Part 80 Map Creation Part 90 Control Part A1,A2 Corrosion Protection Current A3 Macrocell Current L1 First Wiring L2 Second Wiring M1 First Ammeter M2 Second Ammeter P Deterioration Part R Variable Resistor R1 First Variable Resistor R2 Second Variable Resistor S1,S2 Sensor Part

Claims

1. A hull having conductivity, A propeller supported by the hull and formed of a material having a higher potential than the material forming the hull, An anticorrosion device provided on a ship having, An insulator provided on the outer surface of the hull, A sacrificial anode attached to the hull via the insulator, A first wiring for electrically connecting the hull and the propeller, A second wiring provided independently of the first wiring for electrically connecting the hull and the sacrificial anode, A first variable resistor provided on the second wiring, A second variable resistor provided on the first wiring, Comprising, An anticorrosion device not provided with a power source for supplying power to the first wiring and the second wiring in the hull.

2. A hull having conductivity, A propeller supported by the hull and formed of a material having a higher potential than the material forming the hull, An anticorrosion device provided on a ship having, An insulator provided on the outer surface of the hull, A sacrificial anode attached to the hull via the insulator, A first variable resistor provided between the sacrificial anode and the hull, A second variable resistor provided between the propeller and the hull, Comprising, A sensor unit provided on the outer surface of the hull for detecting an underwater electric field, A control unit for changing the resistance value of at least one of the first variable resistor and the second variable resistor based on an input from the sensor unit, An anticorrosion device further comprising.

3. A first ammeter provided between the sacrificial anode and the first variable resistor, A second ammeter provided between the propeller and the second variable resistor, Further comprising, The control unit is configured to change the resistance value of at least one of the first variable resistor and the second variable resistor based on the current values measured by the first ammeter and the second ammeter. The anticorrosion device according to claim 2.

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