Anti-corrosion device

Abstract

To provide a corrosion prevention device capable of changing magnitude of corrosion prevention current as necessary.SOLUTION: A corrosion prevention device 100 that is a corrosion prevention device provided on a marine vessel having a hull 1 having conductivity includes: a plurality of insulators 2 provided on the outer surface of the hull; a plurality of sacrificial anodes 3 that are mounted on the hull through the insulators and perform corrosion prevention of a propeller 41; a plurality of auxiliary anodes 6 provided in places different from the sacrificial anodes; a plurality of first variable resistors R1 provided between the sacrificial anodes and the hull; and a plurality of second variable resistors R2 provided between the auxiliary anodes and the hull. The above configuration can provide a corrosion prevention device capable of changing magnitude of corrosion prevention current as necessary.SELECTED DRAWING: Figure 1

Description

Technical Field

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

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 it has a lower potential than 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 field (UEP: Underwater Electric Potential) 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.

Means for Solving the Problems

[0006] To solve the above problems, the corrosion prevention device according to the present disclosure is a corrosion prevention device provided on a ship having a conductive hull, and includes a plurality of insulators provided on the outer surface of the hull, a plurality of sacrificial anodes attached to the hull via the insulators, a plurality of first variable resistors provided between the sacrificial anodes and the hull, and a plurality of second variable resistors provided between the auxiliary anodes and the hull. inside the hull, for the anticorrosion device Power supply a power source that generates an anticorrosion current by doing this It does not include. The corrosion prevention device according to the present disclosure is a corrosion prevention device provided on a ship having a conductive hull, and includes a plurality of insulators provided on the outer surface of the hull, a plurality of sacrificial anodes attached to the hull via the insulators to prevent corrosion of the propeller, a plurality of auxiliary anodes provided at locations different from the sacrificial anodes, a plurality of first variable resistors provided between the sacrificial anodes and the hull, a plurality of second variable resistors provided between the auxiliary anodes and the hull, a first ammeter provided between the sacrificial anode and the first variable resistor, and a second ammeter provided between the auxiliary anode and the second variable resistor. provided on the outer surface of the hull, comprising a sensor unit that detects an underwater electric field, and a control unit that changes the resistance values of the first variable resistor and the second variable resistor based on an input from the sensor unit The control unit is configured to change the resistance values of the first variable resistor and the second variable resistor based on the current values measured by the first ammeter and the second ammeter.

Advantages of the Invention

[0007] According to the present disclosure, it is possible to provide a corrosion prevention device capable of changing the magnitude of the corrosion prevention current as needed.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0009] <First Embodiment> (Configuration of Ship) Hereinafter, the corrosion prevention device 100 according to the first embodiment of the present disclosure will be described with reference to FIG. 1. The corrosion prevention device 100 is a device for performing corrosion prevention 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 corrosion prevention device 100.

[0010] 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.

[0011] 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 body 41, a shaft 42, a grounding portion 43, and a bearing 5. The propeller 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 body 41. The shaft 42 is supported by the hull 1 in a rotatable state about the central axis via the bearing 5.

[0012] A grounding portion 43 is provided on a part of the shaft 42 inside the hull 1. The grounding portion 43 is provided to electrically connect (ground) the hull 1 and the propeller 4. Specifically, the grounding portion 43 and the hull 1 are electrically connected through the first wiring L1.

[0013] Also, the propeller 4 is formed of a copper alloy as an example. That is, the propeller 4 has a higher electric potential than the hull 1 formed of iron described above.

[0014] (Configuration of Corrosion Prevention Device) The anticorrosion device 100 has a plurality of insulators 2, sacrificial anodes 3, a plurality of auxiliary anodes 6, a plurality of first variable resistors R1, and second variable resistors R2. Each insulator 2 is fixedly arranged at intervals on the outer surface 1B of the hull 1. As the insulator 2, a resin material such as rubber is preferably used. A sacrificial anode 3 or an auxiliary anode 6 is attached to each of these insulators 2. That is, the sacrificial anode 3 and the auxiliary anode 6 are fixed to the outer surface 1B of the hull 1 via the insulator 2.

[0015] The sacrificial anode 3 is formed of a metal material having a lower potential than iron, such as zinc for example. These insulators 2 and the sacrificial anode 3 are provided in the vicinity of the propeller 4 on the outer surface 1B of the hull 1.

[0016] The first variable resistor R1 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 first variable resistor R1 is provided on this second wiring L2. Also, a plurality of second variable resistors R2 are provided at locations different from the first variable resistor R1. The second variable resistor R2 is also a resistor capable of freely changing its resistance value. The auxiliary anode 6 and the hull 1 are electrically connected by a third wiring L3. The second variable resistor R2 is provided on this third wiring L3. The anticorrosion device 100 is configured as described above and does not include an external power source for supplying power from the outside.

[0017] Next, the operation of the anticorrosion device 100 will be described. When the ship S is performing normal navigation, in the anticorrosion 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 with a higher potential than zinc becomes the cathode.

[0018] As a result, through the seawater between the sacrificial anode 3 and the propeller 4, the grounding portion 43 of the propeller 4, the first wiring L1, and the hull 1 are electrically connected. 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, the current generated between the propeller 4 and the hull 1 can be greatly suppressed, and corrosion of the propeller 4 can be suppressed.

[0019] 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.

[0020] 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.

[0021] Therefore, in the present embodiment, a first variable resistor R1 is provided on the second wiring L2. In order to change the magnitude of the underwater electric field using the corrosion prevention device 100, first, the resistance value of this first variable resistor R1 is changed. By changing the resistance value of the variable resistor R, 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.

[0022] More specifically, by adjusting the resistance value of the first variable resistor R1 in the increasing direction, the magnitude of the anticorrosion current A1 can be reduced. On the other hand, to increase the anticorrosion 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 becomes possible to control the magnitude of the underwater electric field formed by the anticorrosion current A1 as needed. Further, in the above configuration, the magnitude of the underwater electric field can be controlled without receiving a large power supply from an external power source. Note that the insulator 2 is provided to prevent the anticorrosion current A1 from flowing directly from the sacrificial anode 3 to the hull 1 and not passing through the variable resistor R.

[0023] Here, as shown as the deteriorated portion P in FIG. 1, on the outer surface 1B of the hull 1, the coating film may peel off, or the chemical structure of the coating film may change over time, so that the resistance value of the coating film of the deteriorated portion P may become small.

[0024] In this case, when the anticorrosion device 100 is in operation, the hull 1 of this deteriorated portion P may become an anode, and the macrocell current between the hull 1 and the propeller 4 may increase. Specifically, with the deteriorated portion 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, and a macrocell current is generated. In particular, when the deteriorated portion P is largely separated from the propeller 4, there is a risk that the underwater electric field in the distance increases due to an increase in the dipole moment.

[0025] However, in the present embodiment, in addition to the sacrificial anode 3 for preventing corrosion of the propeller, a plurality of auxiliary anodes 6 are provided on the outer surface 1B. When there is no deteriorated portion in the hull coating, the variable resistor R2 on the third wiring L3 of the auxiliary anode 6 is maximized to cut off unnecessary anticorrosion current. Only when a deteriorated portion P occurs in the hull coating, the variable resistor R2 on the third wiring L3 of the auxiliary anode 6 located closest is decreased to generate an anticorrosion current Ap between the deteriorated portion P. In this case, since the dipole moment becomes smaller compared to the case where the anticorrosion current flows from the distant sacrificial anode 3, an increase in the distant underwater electric field caused by the deteriorated portion P can be avoided.

[0026] The above describes the first embodiment of the present disclosure. Note that, without departing from the gist of the present disclosure, various changes and modifications can be made to the above configuration. For example, in the above first embodiment, an example in which zinc is used as the sacrificial anode 3 and the auxiliary anode 6 has been described. However, as the sacrificial anode 3 and the auxiliary anode 6, in addition to zinc, any metal having a lower potential than copper, such as aluminum, magnesium, iron, etc., can be preferably used. Further, as trace elements thereof, aluminum, zinc, cadmium, magnesium, indium, titanium, iron, tin, manganese, etc. may be included.

[0027] <Second Embodiment> Subsequently, the second embodiment of the present disclosure will be described with reference to FIG. 2. Note that the same components as those in the above first embodiment are denoted by the same reference numerals, and detailed descriptions thereof are omitted. As shown in FIG. 2, the corrosion prevention device 100 according to the present embodiment further includes a sensor unit S, 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 above first embodiment.

[0028] The sensor unit S is a device provided on the outer surface 1B of the hull 1 and measures the potential (underwater electric field) in seawater. Specifically, the sensor unit S has two electrodes, and uses the potential measured by one electrode as the reference potential and the potential measured by the other electrode as the actual value for detection. Therefore, it is desirable that not only one but also a plurality of sensor units S are provided. Note that, in FIG. 2, only one sensor unit S is illustrated for simplicity of illustration.

[0029] The potential measured by the sensor unit S 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 hull 1 based on the measured values of the underwater electric field at the inputted 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 the variable resistor R described above as necessary based on the distribution of the underwater electric field input from the underwater electric field distribution prediction unit 80.

[0030] According to the above configuration, based on the actual magnitude of the underwater electric field detected by the sensor unit S, the control unit 90 changes the resistance values of the first variable resistor R1 and the second variable resistor R2. Thereby, according to the magnitude and distribution shape of the underwater electric field that changes over time due to factors such as deterioration of the hull coating, the anticorrosion currents A1 and Ap (the same as those described in the first embodiment based on FIG. 1) can be controlled more freely and precisely, and an increase in the underwater electric field in the distance can be prevented.

[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, the third embodiment of the present disclosure will be described with reference to FIG. 3. 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. 3, the anticorrosion device 100 according to the present embodiment further includes a plurality of ammeters M in addition to the configuration described in the second embodiment.

[0033] The ammeters M are provided on the second wiring L2 and the third wiring L3 on the sacrificial anode 3 side and the auxiliary anode 6 side of the resistors R1 and R2, respectively. The ammeters M measure the magnitude of the current flowing through the second wiring L2 and the third wiring L3 and send it to the control unit 90 as an electrical signal.

[0034] In addition to the underwater electric field distribution information obtained by the sensor unit S described in the above-described second embodiment, the control unit 90 changes the resistance value of the variable resistor R based on the magnitudes of the currents flowing through the second wiring L2 and the third wiring L3. That is, the magnitudes of the corrosion prevention currents A1 and Ap (which are the same as those described in the first embodiment with reference to FIG. 1) that are occurring at a certain point in time are fed back to the control unit 90 as electrical signals. Based on this electrical signal, the control unit 90 performs feedback control to control the magnitudes of the corrosion prevention currents A1 and Ap.

[0035] As described above, according to the above configuration, based on the actual current values measured by the ammeter M, the control unit 90 changes the resistance values of the first variable resistor R1 and the second variable resistor R2. As a result, the magnitudes of the corrosion prevention currents A1 and Ap are fed back to the control unit 90, and it becomes possible for the control unit 90 to more freely and precisely control the magnitude of the underwater electric field.

[0036] The third 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.

[0037] <Supplementary Note> The corrosion prevention device 100 described in each embodiment and the method of operating the corrosion prevention device 100 are understood as follows, for example.

[0038] (1) The corrosion prevention device 100 according to the first aspect is a corrosion prevention device 100 provided on a ship S having a hull 1 with conductivity, including a plurality of insulators 2 provided on the outer surface 1B of the hull 1, a sacrificial anode 3 attached to the hull via the insulator 2 for preventing corrosion of the propeller, a plurality of auxiliary anodes 6 provided at locations different from the sacrificial anode 3, a first variable resistor R1 provided between the sacrificial anode 3 and the hull 1, and a plurality of second variable resistors R2 provided between the auxiliary anode 6 and the hull 1.

[0039] According to the above configuration, 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. Thereby, it becomes possible to control the magnitude of the underwater electric field as needed.

[0040] (2) The corrosion prevention device 100 according to the second aspect is provided on the outer surface 1B of the hull 1, and further includes a sensor unit S that detects an underwater electric field, and a control unit 90 that changes the resistance values of the first variable resistor R1 and the second variable resistor R2 based on an input from the sensor unit S.

[0041] According to the above configuration, based on the magnitude of the actual underwater electric field detected by the sensor unit S, 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.

[0042] (3) The corrosion prevention 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 auxiliary anode 6 and the second variable resistor R2, and the control unit 90 is configured to change the resistance values 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.

[0043] 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 values of the first variable resistor R1 and the second variable resistor R2. Thereby, the magnitude of the corrosion prevention current A1 is fed back to the control unit 90, and it becomes possible for the control unit 90 to control the magnitude of the underwater electric field more freely and precisely.

Explanation of Reference Numerals

[0044] 100 Corrosion prevention device 1 Hull 1B Outer surface 2 Insulator 3 Sacrificial Anode 4 Propeller 5 Bearing 6 Auxiliary Anode 41 Propeller Body 42 Shaft 43 Grounding Part 70 Input Part 80 Prediction Unit for Electric Field Distribution in Water 90 Control Unit A1, A2, Ap Corrosion Protection Current L1 First Wiring L2 Second Wiring L3 Third Wiring M1 First Ammeter M2 Second Ammeter P Deterioration Part R1 First Variable Resistor R2 Second Variable Resistor S Sensor Part

Claims

1. An anticorrosion device provided on a ship having a conductive hull, comprising: a plurality of insulators provided on the outer surface of the hull; a plurality of sacrificial anodes attached to the hull via the insulators to prevent corrosion of the propeller; a plurality of auxiliary anodes provided at locations different from those of the sacrificial anodes; a plurality of first variable resistors provided between the sacrificial anodes and the hull; a plurality of second variable resistors provided between the auxiliary anodes and the hull; and an anticorrosion device not provided with a power source for generating an anticorrosion current by supplying power to the anticorrosion device within the ship.

2. a sensor unit provided on the outer surface of the hull for detecting an underwater electric field; and a control unit for changing the resistance values of the first variable resistor and the second variable resistor based on an input from the sensor unit. The anticorrosion device according to claim 1, further comprising:

3. An anticorrosion device provided on a ship having a conductive hull, comprising: a plurality of insulators provided on the outer surface of the hull; a plurality of sacrificial anodes attached to the hull via the insulators to prevent corrosion of the propeller; a plurality of auxiliary anodes provided at locations different from those of the sacrificial anodes; a plurality of first variable resistors provided between the sacrificial anodes and the hull; a plurality of second variable resistors provided between the auxiliary anodes and the hull; a first ammeter provided between the sacrificial anode and the first variable resistor; a second ammeter provided between the auxiliary anode and the second variable resistor; a sensor unit provided on the outer surface of the hull for detecting an underwater electric field; and a control unit for changing the resistance values of the first variable resistor and the second variable resistor based on an input from the sensor unit. The anticorrosion device comprises: The control unit is configured to change the resistance values of the first variable resistor and the second variable resistor based on the current values measured by the first ammeter and the second ammeter.

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