JP7090270B1 - Foreign matter adhesion prevention device - Google Patents

Abstract

Provided is a foreign matter adhesion prevention device that ensures safety and prevents foreign matter from adhering to the window surface of an underwater structure. It has a light emitting unit 20 that irradiates the inspection window surface 110 of the underwater structure 100 with the irradiation light, and a shielding unit 30 that can prevent the irradiation light from leaking into the underwater structure 100. Has a peak in the wavelength range of 405 to 412 nm, and the irradiation light has an irradiation intensity of 25 Wm-2 when the divalent iron ion concentration in the water outside the window surface is less than 0.1 mg / L. When the divalent iron ion concentration in the water outside the window surface is 0.1 mg / L or more, the irradiation intensity is in the range of 25 Wm-2 to 100 Wm-2. Foreign matter adhesion prevention device 1, which is light. By irradiating the inspection window surface 110 with the above irradiation light, adhesion of a film formed by an attached organism or a biofilm or a compound containing iron is suppressed.

Description

The present invention relates to a foreign matter adhesion prevention device.

Underwater structures installed underwater, such as seawater system equipment in power generation facilities such as thermal power plants and nuclear power plants, are provided with glass or acrylic inspection windows for equipment inspection. It is known that sessile organisms such as barnacles and mussels and foreign substances such as biofilms are likely to adhere to such underwater structures and their inspection windows. When foreign matter adheres to the inspection window, it is difficult to see the outside from the inspection window, and it is difficult to inspect the underwater structure. Therefore, the inspection window may be provided with a scraper for removing the foreign matter by rotating the wiper.

However, the scraper may not be able to completely remove foreign matter firmly attached to the inspection window. Therefore, a technique for preventing the adhesion of organisms to the window surface by irradiating the window surface of the underwater device with ultraviolet rays is disclosed (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2006-281082

The technique disclosed in Patent Document 1 is a technique for preventing the adhesion and growth of living organisms by irradiating an optical window that transmits light with ultraviolet rays. However, since ultraviolet rays are harmful to the human eye, it is not preferable to leak them to the outside where they can be seen by the human eye. In addition to sessile organisms and biofilms, iron compounds also form a film on the surface of inspection windows, which was clarified by the studies by the inventors. However, the current situation is that the method for preventing the formation of the above-mentioned film has not been disclosed.

The present invention has been made in view of the above, and an object of the present invention is to provide a foreign matter adhesion prevention device that ensures safety and prevents foreign matter from adhering to the window surface of an underwater structure.

(1) The present invention has a light emitting portion that irradiates the window surface of the underwater structure with the irradiation light, and a shielding portion that can prevent the irradiation light from leaking into the underwater structure. The irradiation light has a peak in the wavelength range of 405 to 412 nm, and the irradiation light has an irradiation intensity of 25 Wm when the divalent iron ion concentration in the water outside the window surface is less than 0.1 mg / L. The irradiation light is ^-2 or more, and when the divalent iron ion concentration in the water outside the window surface is 0.1 mg / L or more, the irradiation intensity is in the range of 25 Wm ^-2 to 100 Wm ^-2 . It relates to a foreign matter adhesion prevention device, which is the light inside.

(2) The foreign matter adhesion prevention device according to (1), wherein the adhesion of attached organisms or biofilms to the window surface is suppressed by irradiation with the irradiation light.

(3) The foreign matter adhesion prevention device according to (1) or (2), wherein the adhesion of a film formed by a compound containing iron to the window surface is suppressed by irradiation with the irradiation light.

(4) The shielding portion is between a closed state in which the irradiation light is prevented from leaking into the underwater structure and an open state in which the window surface is visible from the inside of the underwater structure. The foreign matter adhesion prevention device according to any one of (1) to (3), which is provided so as to be openable and closable with respect to the window surface and is irradiated with the irradiation light only in the closed state.

(5) The light emitting unit has a control unit and a sensor unit, the sensor unit can detect the open state and the closed state, and the sensor unit detects the open state. In that case, the control unit controls to stop the irradiation of the irradiation light, and when the sensor unit detects the closed state, the control unit controls to irradiate the irradiation light. The foreign matter adhesion prevention device according to (4).

(6) The shielding portion has a lock mechanism capable of holding the closed state, and the lock mechanism holds the closed state when the irradiation light is irradiated, and the closed state when the irradiation light is not irradiated. The foreign matter adhesion prevention device according to (4) or (5), which releases the holding of.

(7) The light emitting unit has an LED light emitting panel including a plurality of LED light emitting elements, and irradiates at least half the area of the window surface with the irradiation light according to any one of (1) to (6). The described foreign matter adhesion prevention device.

(8) The shielding portion has a conical shape that extends with respect to the window surface, and the light emitting portion is arranged at the apex of the shielding portion having the conical shape, and the irradiation light is applied to the window surface. The foreign matter adhesion prevention device according to any one of (1) to (6), which has a point light source for irradiating.

(9) The foreign matter adhesion prevention device according to any one of (1) to (8), wherein the window surface is a window portion for inspection in the underwater structure.

INDUSTRIAL APPLICABILITY The present invention can provide a foreign matter adhesion prevention device that ensures safety and prevents foreign matter from adhering to the window surface of an underwater structure.

It is a block diagram which shows the foreign matter adhesion prevention apparatus 1 which concerns on 1st Embodiment of this invention. It is a block diagram which shows the foreign matter adhesion prevention apparatus 1a which concerns on 2nd Embodiment of this invention. It is a block diagram which shows the foreign matter adhesion prevention apparatus 1b which concerns on 3rd Embodiment of this invention. It is a block diagram which shows the foreign matter adhesion prevention apparatus 1c which concerns on 4th Embodiment of this invention. It is a figure which shows the structure of a part of the light emitting part which concerns on 1st Embodiment of this invention. It is a figure which shows the structure of the shielding part which concerns on 1st Embodiment of this invention. It is a photograph which shows the state of biofouling to the attachment plate in one Example of this invention. It is a photograph which shows the state of biofouling to the attachment plate in one Example of this invention. It is a schematic diagram of the test which irradiates the window surface of an underwater structure with light of different irradiation intensities. It is a photograph which shows the test result which irradiated the window surface of an underwater structure with light of different irradiation intensities. It is a photograph which shows the test result which irradiated the window surface of an underwater structure with light of different irradiation intensities. It is a schematic diagram of the test which irradiates the window surface of an underwater structure with light of a specific irradiation intensity. It is a photograph which shows the test result which irradiated the window surface of an underwater structure with light of a specific irradiation intensity. It is a photograph which shows the test result which irradiated the window surface of an underwater structure with light of a specific irradiation intensity. It is a photograph which shows the test result which irradiated the window surface of an underwater structure with light of a specific irradiation intensity. It is a photograph which shows the test result which irradiated the window surface of an underwater structure with light of a specific irradiation intensity.

Hereinafter, embodiments of the present invention will be described. The present invention is not limited to the following embodiments, and can be appropriately modified.

[First Embodiment]
As shown in FIG. 1, the foreign matter adhesion prevention device 1 according to the present embodiment prevents foreign matter from adhering to the inspection window surface 110, which is the inspection window portion of the underwater structure 100. The underwater structure 100 is not particularly limited, and examples thereof include seawater system equipment (filter, sponge ball cleaning device, shell removal device) in a power generation facility such as a thermal power plant and a nuclear power plant. These facilities are equipped with inspection windows for checking the operating status such as backwashing of the filter.

The underwater structure 100 is not limited to the above, and is not limited to the above. Cooling water cooler, lubricating oil cooler, LNG vaporizer, generator, drainage pipeline, water wheel, impeller, valve, rotary shaft, headrace pipeline, filter tank, membrane, dam, ship, hull in shipyard, ballast water It may be a tank, a ballast water introduction / discharge pipe, pumps, aquatic culture equipment, a fishery test site, aquatic equipment, an aquarium, a water tank in a fish and shellfish breeding water tank, pipes, pumps and the like.

Iron ions may be injected into the seawater, freshwater, or brackish water around the underwater structure 100 for the purpose of preventing corrosion of the underwater structure 100. For example, in a condenser of a power plant, an injection device that injects an iron ion source such as ferrous sulfate into seawater, fresh water, or steam water around the condenser in order to prevent corrosion of the condenser capillary tube. May be provided. The injection device injects divalent iron ions so that the divalent iron ion concentration is, for example, 0.3 ppm × 6 hours / day or the divalent iron ion concentration is 1.0 ppm × 2 hours / day at the time of initial operation. .. The injection device injects divalent iron ions so that the divalent iron ion concentration is, for example, 0.1 ppm × 6 hours / day or the divalent iron ion concentration is 0.5 ppm × 1 hour / day during normal operation. .. However, when the concentration of divalent iron ions outside the inspection window surface 110 is 0.1 mg / L or more, the inspection window surface 110 contains not only sessile organisms or biofilms but also iron caused by the iron ions. The compound can form an iron film and impair visibility for equipment inspection.

The material constituting the inspection window surface 110 is not particularly limited as long as it is a light-transmitting member, and for example, glass such as quartz glass and soda glass, light-transmitting resin such as acrylic and polyvinyl chloride, and the like are used. Can be mentioned. The inspection window surface 110 is provided with a scraper 111 for removing foreign matter adhering to the inspection window, for example. The scraper 111 is configured to rotate a wiper provided on the outside (underwater side surface) of the inspection window by rotating the handle to remove foreign matter adhering to the outer surface of the inspection window. However, with the scraper 111 alone, it may be difficult to firmly remove foreign matter adhering to the inspection window surface 110 and secure visibility for equipment inspection.

As shown in FIG. 1, the foreign matter adhesion prevention device 1 according to the present embodiment has a light emitting unit 20 and a shielding unit 30. The light emitting unit 20 has a peak in the wavelength range of 405 to 412 nm, and irradiates the inspection window surface 110 with irradiation light having an irradiation intensity of 25 Wm ^-2 or more. As a result, adhesion of adhered organisms or foreign substances such as biofilm to the inspection window surface 110 is suppressed. When the divalent iron ion concentration in the water outside the inspection window surface 110 is 0.1 mg / L or more, the irradiation intensity of the irradiation light is adjusted within the range of 25 Wm ^-2 to 100 Wm ^-2 . As a result, in addition to the adhesion of attached organisms or biofilms to the inspection window surface 110, the adhesion of the film formed by the iron-containing compound is suppressed. The shielding unit 30 can cover the light irradiation unit 21 and prevents the irradiation light harmful to the human eye from leaking into the underwater structure 100. The water passage point of the underwater structure 100 is inside a part of the underwater structure 100 shown in the cylindrical shape in FIG. The inspector of the underwater structure 100 can inspect the operating status of the underwater structure 100 by visually recognizing the water passage portion through, for example, the inspection window surface 110. In the present specification, the "outside of the underwater structure" is the outside of the underwater structure, and is a concept including the above-mentioned water passage point. Further, the "inside of the underwater structure" means the inside of the underwater structure 100 and the area on the inspector side with respect to the inspection window surface 110. That is, the above water passage point is not included in the concept of "inside the underwater structure".

FIG. 1A shows a closed state of the shielding portion 30 (hereinafter, may be simply referred to as a “closed state”) in which the leakage of the irradiation light into the underwater structure 100 is prevented, and FIG. B) shows an open state of the shielding portion 30 (hereinafter, may be simply referred to as “open state”) in which the inspection window surface 110 becomes visible from the inside of the underwater structure 100. The shielding portion 30 is kept in a closed state except when the underwater structure 100 is inspected.

The above-mentioned attached organisms are floating in the sea during the early larvae, and when they become adherent larvae, they are organisms that attach to appropriate deposits and metamorphose into adults, and examples thereof include mussels and barnacles.

Mussels are a general term for bivalves of the Musaceae family, such as Limnoperna fortunei, Lithophagainae, Lithophagainae, Lithophagainae, and Lithophagainae. Crenellinae), Lithophaga curta, Limnoperna fortunei, Lithophaga curta, and the like are included. The barnacles are a general term for those classified into crustacea, cerlipadia, and barnacles, such as barnacles, barnacles, barnacles, barnacles, and barnacles. Includes those belonging to the barnacle-type suborder (Balanomophorpha), including barnacles, barnacles, barnacles, barnacles, barnacles, and barnacles of Europe.

The biofilm is a structure formed by microorganisms on the surface of a window surface such as an inspection window surface of an underwater structure. Biofilms are usually membranous and contain extracellular high molecular weight substances (EPS, extracellular polymer substance) such as polysaccharides secreted by microorganisms. The biofilm may also contain microbial remains, excrement, feces, burrows and the like. Here, the microorganism can be exemplified by an organism belonging to bacteria, fungi, blue-green algae, protozoa and the like. It also includes microalgae such as adherent diatoms, green algae, brown algae and red algae, and larvae such as kaimen, hydroins, jellyfish, tube-dwelling polychaetes, gammaridea and gammaridea.

The iron-containing compound is a compound produced by oxidizing iron ions in water, and the iron-containing compound forms a film on the surface of the inspection window surface 110. Iron ions in water may be injected into water for the purpose of anticorrosion of the underwater structure 100. Examples of the iron-containing compound include iron (II) oxide (FeO), iron (III) oxide (Fe ₂ O ₃ ), iron oxyhydroxide (FeOOH), iron hydroxide (Fe (OH) ₂ ), and the like. Examples thereof include ferric hydroxide (Fe (OH) ₃ ). The reason why the formation of the film is suppressed by irradiating the inspection window surface 110 with the irradiation light is not clear, but for example, the following reasons can be considered. Since the iron-containing compound is negatively charged in seawater and the inspection window surface 110 is positively charged, an electrostatic attractive force acts on the inspection window surface 110, and the iron-containing compound is applied to the inspection window surface 110. Is deposited to form a film. However, it is considered that the irradiation of the irradiation light suppresses the positive charge of the inspection window surface 110, and as a result, the deposition of the iron-containing compound on the inspection window surface 110 is suppressed.

The irradiation light emitted from the light emitting unit 20 has a peak in the wavelength range of 405 to 412 nm. Ultraviolet rays having a wavelength of 380 nm or less have an effect of suppressing attached organisms, but have a problem of low transmittance in seawater. By setting the wavelength of the irradiation light in the above range, a preferable adhesion suppressing effect can be obtained. The irradiation light preferably has a peak in the wavelength range of 400 to 420 nm. The wavelength of the irradiation light may include a wavelength range other than the above as long as the effect of the present invention is not impaired. For example, it may contain light in the wavelength range of 400 to 440 nm.

The irradiation intensity of the irradiation light is 25 Wm ^-2 or more when the divalent iron ion concentration in the water outside the inspection window surface 110 is less than 0.1 mg / L. The irradiation intensity of the irradiation light is in the range of 25 to 100 Wm ^-2 when the divalent iron ion concentration in the water outside the inspection window surface 110 is 0.1 mg / L or more. The irradiation intensity is preferably in the range of 25 to 50 Wm ^-2 when the concentration of divalent iron ions in the water outside the inspection window surface 110 is 0.1 mg / L or more. The irradiation intensity is a value obtained as a measured value of Pyranometer LI-200 manufactured by Meiwaforsis Co., Ltd. As a result, the adhesion of foreign matter to the inspection window surface 110 is preferably suppressed. When the concentration of divalent iron ions in the water outside the inspection window surface 110 is 0.1 mg / L or more and the irradiation intensity of the irradiation light exceeds 100 Wm ^-2 , the adhesion of the film formed by the iron-containing compound is suppressed. On the contrary, there is a risk of promoting the formation of an iron film due to the photooxidative action. If the irradiation intensity of the irradiation light is less than 25 Wm ^-2 , it may not be possible to obtain a sufficient effect of suppressing the adhesion of attached organisms. The irradiation time of the light is not particularly limited and may be continuous or intermittent. When it is intermittent, it is preferable that the average irradiation intensity in a predetermined time is within the above range.

The light emitting unit 20 may be, for example, an LED irradiation device that irradiates LED light, a mercury lamp, a fluorescent tube, or the like. Among them, it is preferable that the LED irradiation device is used, and it is preferable to have an optical fiber that irradiates the LED or an LED light emitting panel composed of a plurality of LED light emitting elements. The light emitting unit 20 according to the present embodiment has an optical fiber.

The light emitting unit 20 includes a light irradiation unit 21 and a main body unit 22. The main body 22 has a control unit (not shown) that controls the light emitted from the light irradiation unit 21. As shown in FIG. 5, the main body portion 22 is housed inside the housing portion 221 and is fixed by the fixing portion 222. Note that FIG. 5A shows a front view of the main body portion 22 and the housing portion 221, FIG. 5B also shows a left side view, and FIG. 5C also shows a right side view. Further, the light emitting unit 20 may have a sensor unit 40.

The light irradiation unit 21 is an exit port of the optical fiber 23, and the irradiation light emitted from the light irradiation unit 21 is applied to the irradiation region L1 which is at least a part of the inspection window surface 110. In the present embodiment, the irradiation region L1 is a partial circular region of the inspection window surface 110. As shown in FIG. 6C, the irradiation light Lc emitted from the light irradiation unit 21 reaches the inspection window surface 110 with a slight spread from the exit port, but is within the surface of the inspection window surface 110. Only irradiated. With the irradiation region L1, there is no risk of deterioration due to irradiation of the shielding portion 30 covering the light irradiation portion 21, and the room for selecting the material constituting the shielding portion 30 can be widened.

The main body 22 is an irradiation device of an LED point light source capable of irradiating LED light as irradiation light. The main body 22 is not particularly limited, and conventionally known ones can be used. As shown in FIG. 5, the main body 22 has a projection lens 220 that irradiates LED light as a point light source. The irradiation light emitted from the light projecting lens 220 is transmitted to the light irradiation unit 21 through the optical fiber 23.

The main body 22 has a control unit (not shown) and can control the irradiation of the LED light emitted from the projection lens 220. The control unit is configured to be communicable with, for example, the sensor unit 40 described later, and when the sensor unit 40 detects an open state, the control unit controls to stop the irradiation of the LED light, and the sensor unit 40 controls the closed state. When is detected, control is performed to irradiate the LED light. As a result, it is possible to reliably prevent the LED light emitted from the light emitting unit 20 from leaking into the underwater structure 100, and it is possible to improve the safety of the foreign matter adhesion prevention device 1.

The sensor unit 40 is configured to be able to communicate with the control unit of the main body unit 22 by wire or wirelessly, and is arranged inside, for example, the door unit 31 of the shielding unit 30 described later. The sensor unit 40 is not particularly limited as long as it is a sensor capable of detecting the open state and the closed state of the shielding unit 30, and is, for example, a magnetic sensor, a pressure sensitive sensor, an ultrasonic sensor, a capacitance sensor, a distance measuring sensor, or the like. A known sensor capable of detecting contact or proximity with the sensor can be used.

The housing portion 221 accommodates the main body portion 22. The housing portion 221 is fixed by the fixing portion 222. The housing portion 221 has a lid portion that can be opened and closed, and the lid portion is fixed by the fixing portion 222.

The fixing portion 222 is a known magnet holder having a magnet such as a neodymium magnet, and can firmly fix an object with a force that cannot be moved by human power, for example, about 800N. The magnetic force of the fixed portion 222 can be switched by the operating portion 223. When the lid portion of the housing portion 221 is released from the fixing by the operation unit 223, the irradiation of the LED light of the main body portion 22 may be stopped. As a result, it is possible to prevent the main body 22 from being operated by accidentally opening the lid of the housing 221 while the LED light is being emitted from the floodlight lens 220 of the main body 22. Therefore, the foreign matter adhesion prevention device 1 The safety of the lens can be further improved.

As shown in FIG. 1, the shielding portion 30 has a door portion 31, a frame portion 32, and an opening / closing mechanism 33. In addition to the above, the shielding portion 30 has a grip portion 34, a locking mechanism 35, and a window portion 36, as shown in FIG. 6 (A) is a top view of the shield 30 in the closed state, FIG. 6 (B) is a front view of the shield 30 in the open state, and FIG. 6 (C) is a right side view of the shield 30 in the closed state. Are shown respectively.

The door portion 31 is connected to the frame portion 32 via the opening / closing mechanism 33, and is provided so as to be openable / closable with respect to the inspection window surface 110. The state in which the door portion 31 is in contact with the frame portion 32 is the closed state, and the state in which the door portion 31 is rotated by the opening / closing mechanism 33 and separated from the frame portion 32 is the open state. As the opening / closing mechanism 33, a known opening / closing mechanism such as a hinge is used.

As shown in FIG. 6, the door portion 31 is a member having a recess on the surface facing the frame portion 32. As shown in FIG. 6B, a light irradiation unit 21 is connected to the front surface of the door unit 31. As shown in FIG. 6C, the LED light emitted from the light irradiation unit 21 is emitted from the front side of the door unit 31 toward the inspection window surface 110. The LED light is emitted in the area surrounded by the recess of the door portion 31 and the frame portion 32 in the closed state and reaches the inspection window surface 110, so that the LED light does not leak into the underwater structure 100.

The frame portion 32 has a shape corresponding to the door portion 31, is arranged so as to surround the circumference of the inspection window surface 110, and is fixed to the underwater structure 100. The frame portion 32 and the door portion 31 are in contact with each other and fixed in the closed state. A member such as packing may be arranged between the door portion 31 and the frame portion 32 in the closed state. This makes it possible to prevent the LED light from leaking from between the door portion 31 and the frame portion 32. The material of the door portion 31 and the frame portion 32 is not particularly limited, and materials such as resin and metal can be used.

The grip portion 34 is a handle for opening and closing the door portion 31. The lock mechanism 35 is a mechanism capable of fixing the closed door portion 31 and the frame portion 32 and holding the closed state. The lock mechanism 35 is not particularly limited, and a known lockable lock mechanism such as a snap lock is used.

It is preferable that the lock mechanism 35 keeps the closed state when the LED light is irradiated, and releases the closed state when the LED light is not irradiated. For example, when the lock mechanism 35 is interlocked with the energizing device or the power supply device that supplies the power for operation to the main body 22 and the holding of the closed state of the lock mechanism 35 is released, the energization to the main body 22 is cut off. Can be configured to be. As a result, since the LED light is not irradiated in the open state, it is possible to reliably prevent the LED light from leaking into the underwater structure 100.

The window portion 36 is provided on the front surface of the door portion 31, and is a window portion that allows the inside of the shielding portion 30 to be confirmed when the shielding portion 30 is closed. The window portion 36 is normally fixed by a fixing tool or the like so that it cannot be opened or closed.

Hereinafter, other embodiments of the present invention will be described. The description of the same configuration as that of the first embodiment may be omitted.

[Second Embodiment]
FIG. 2 is a diagram showing a foreign matter adhesion prevention device 1a according to the second embodiment of the present invention. FIG. 2A shows a closed state of the shielding portion 30a, and FIG. 2B shows an open state of the shielding portion 30a.

The foreign matter adhesion prevention device 1a has a light emitting unit 20a and a shielding unit 30a. In the present embodiment, the light emitting unit 20a has an LED light emitting panel including a plurality of LED light emitting elements. The light emitting unit 20a can adjust the irradiation intensity of the LED light and the like as a whole of the light emitting unit 20a without depending on a single light emitting element. Further, by keeping the output of each LED element low, it can be expected that the life of the device will be extended. The light emitting unit 20a can also make a part of the light irradiation unit 21a emit light.

The light irradiation unit 21a is an LED light emitting panel. The light irradiation unit 21a includes, for example, a plurality of LED elements arranged in a panel frame, a light guide plate, and a reflection sheet. The LED light emitted from the plurality of LED elements toward the center of the panel is uniformly emitted from the entire surface of the panel by the light guide plate and the reflective sheet. The main body 22 has a control unit that supplies electric power to the light irradiation unit 21a and controls the output. The light irradiation unit 21a and the main body unit 22 are connected by a power line and a communication line.

In the present embodiment, the irradiation region L2 of the irradiation light irradiated from the light irradiation unit 21a to the inspection window surface 110 is at least half the area of the inspection window surface 110 as shown in FIG. 2 (B). As a result, a wider area on the inspection window surface 110 where foreign matter is prevented from adhering can be secured as compared with the first embodiment. Therefore, the inspection of the underwater structure 100 can be performed more preferably.

[Third Embodiment]
FIG. 3 is a diagram showing a foreign matter adhesion prevention device 1b according to a third embodiment of the present invention. FIG. 3A shows a closed state of the shielding portion 30b, and FIG. 2B shows an open state of the shielding portion 30b.

The foreign matter adhesion prevention device 1b has a light emitting unit 20b and a shielding unit 30b. In the present embodiment, the light emitting unit 20b has an optical fiber that irradiates the LED light of the point light source, as in the first embodiment. The shielding portion 30b has a door portion 31b having a conical shape that extends with respect to the inspection window surface 110. As shown in FIG. 3, the light irradiation unit 21b of the light emitting unit 20b, which is a point light source, is arranged at the apex of the door portion 31b having a conical shape.

In the present embodiment, the irradiation region L3 of the irradiation light irradiated from the light irradiation unit 21b to the inspection window surface 110 is a region including the entire surface of the inspection window surface 110 as shown in FIG. 3 (B). As a result, it is possible to prevent foreign matter from adhering to the entire surface of the inspection window surface 110, and it is possible to more preferably inspect the underwater structure 100. Further, the above can be realized by a simple configuration using a point light source.

[Fourth Embodiment]
FIG. 4 is a diagram showing a foreign matter adhesion prevention device 1c according to the fourth embodiment of the present invention. FIG. 4A shows a closed state of the shielding portion 30c, and FIG. 4B shows an open state of the shielding portion 30c.

The foreign matter adhesion prevention device 1c has a light emitting unit 20c and a shielding unit 30c. Like the light emitting unit 20a, the light emitting unit 20c includes an LED light emitting panel including a plurality of LED light emitting elements. Therefore, the foreign matter adhesion prevention device 1c has the same configuration as the foreign matter adhesion prevention device 1a according to the second embodiment, and the same effect can be obtained.

The light irradiation unit 21c is an LED light emitting panel. The LED light emitting panel can be freely shaped, and the light irradiation unit 21c has a shape corresponding to the inspection window surface 110. Therefore, as shown in FIG. 4B, the irradiation region L4 of the irradiation light emitted from the light irradiation unit 21c to the inspection window surface 110 is a region including the entire surface of the inspection window surface 110. As a result, it is possible to prevent foreign matter from adhering to the entire surface of the inspection window surface 110, and it is possible to more preferably inspect the underwater structure 100.

The present invention is not limited to the above embodiment, and can be appropriately modified.
In the above embodiment, the window surface of the underwater structure 100 has been described as the inspection window surface 110, but the present invention is not limited to the above. The window surface may have a purpose other than inspection.

Hereinafter, the present invention will be described in more detail by way of examples, but the contents of the present invention are not limited to the contents of the following examples.

<1> Outdoor immersion test of affixa plate In this example, a PVC affixa plate is immersed in the sea on the premises of the Hiroshima Prefectural Fisheries and Marine Technology Center with a weight of 5 kg to a depth of 2 m, and a rope and metal are used. It was fixed in the sea using a chain. Using an optical fiber covered with a waterproof tube from an LED light source installed on the sea, the LED light having a peak wavelength of 405 nm was irradiated to the immersed affixa in the sea. For comparison, a immersion test was also performed on the affixa plate not irradiated with LED light.

As the LED light source, a high power LED light source manufactured by U-Technology Co., Ltd. was used. The irradiation intensity of the LED light of the affixa plate was adjusted so that the irradiation intensity of each affixa plate at a distance of 10 cm from the optical fiber ejection port was 1000 Wm ^-2 .

<2> Adhesion status of attached organisms or biofilm by irradiation with LED light The adhesion status of attached organisms or biofilm to the affixa 1 month and 2 months after the start of the immersion test of <1> was confirmed. FIG. 7 is a photograph showing the adhesion state one month after the start of the test, and FIG. 8 is a photograph showing the adhesion state two months after the start of the test.

In FIGS. 7 and 8, in order from the left, photographs of the affixa plate without light irradiation and with LED light having a peak wavelength of 405 nm are shown. The scale on the right side indicates the distance (cm) from the optical fiber outlet. As is clear from FIGS. 7 and 8, the attachment plate irradiated with the LED light having a peak wavelength of 405 nm is in the irradiation range of the LED light radially emitted from the optical fiber ejection port arranged on the upper part of the attachment plate. The result was that no attached organisms or biofilms were attached. On the other hand, it was clear that the attachment plate not irradiated with the LED light had attached organisms, biofilms, and the like adhered to the entire surface.

<3-1> Irradiation test of LED light to the inspection window surface of underwater structure 1
Replace the inspection window (made of acrylic resin) of the shell remover in the condenser of the coal-fired power plant equipped with the ferrous sulfate injection device with a new one, and replace the inspection window with three types of LEDs with different irradiation intensities. Irradiated with light. Specifically, as shown in FIGS. 9A and 9B, the inspection window surface 110 is divided into 4 sections by a light-shielding plate S, and the irradiation intensities are 25 Wm ^-2 and 50 Wm for 3 sections, respectively. ^-2 , 200 ^Wm -LED light with a peak wavelength of 405 nm was continuously irradiated to make a test group. The irradiation regions L are regions of about 40 mm × 40 mm, respectively, as shown in FIG. 9A, and the irradiation intensities on the inspection window surface 110 are set to the above-mentioned irradiation intensities. As the LED light source, the LED module SRDB-40UV40-405 (manufactured by U-Technology Co., Ltd.) was used so that the distance between the light irradiation unit 21 and the inspection window surface 110 was 100 mm. In addition, other inspection windows of the same shell removal device were replaced with new ones at the same time to make a control section.

FIG. 10 is a photograph of the test group taken 11 weeks after the start of the test, and FIG. 11 is a photograph of the control group taken 11 weeks after the start of the test. Arrows W in FIGS. 10 and 11 indicate the direction of the water flow. The white spots in the inspection windows of FIGS. 10 and 11 are spots to which barnacles B have adhered. As shown in FIGS. 10 and 11, many barnacles B adhered to the upstream side of the water flow W where seawater tends to stay. In FIG. 10, which shows the test plot, the adhesion of barnacles B and biofilm was suppressed in the vicinity of the light irradiation region L of 25 Wm ^-2 and 50 Wm ^-2 on the left half surface of the inspection window. In addition, the formation of a thick yellow iron hydroxide film was confirmed in the irradiation region L of 200 Wm ^-2 . The formation of iron hydroxide film was also confirmed at 25 Wm ^-2 and 50 Wm ^-2 , but it was very thin and the formation of iron film was suppressed. Further, the biofilm was attached to the inspection window surface 110 other than the irradiation region L. On the other hand, in FIG. 11 showing the control section, barnacles B were concentratedly adhered to the left half surface of the inspection window. In addition, the entire surface was covered with thick detritus (which is thought to be biofilmed by the bacteria existing inside it). Therefore, by setting the irradiation intensity of the LED light of 405 nm to the range of 25 Wm ^-2 to 100 Wm ^-2 , the adhesion of attached organisms and biofilm can be suppressed, and the adhesion of the film formed by the compound containing iron can be suppressed. Results that can be suppressed were confirmed.

<3-2> Inspection of underwater structure LED light irradiation test on window surface 2
For the two inspection windows (made of acrylic resin) of the shell remover in the condenser of a coal-fired power plant equipped with a ferrous sulfate injection device, the irradiation intensity is 50 Wm ^-2 and 200 Wm ^-2 , respectively, and the peak wavelength is 405 nm. The test plot was set by continuously irradiating with LED light. Specifically, the irradiation region L is a circular region having a diameter of 50 mm (diameter 60 mm on the light emitting surface from the inspection window) shown in FIGS. 12 (A) and 12 (B), and the irradiation intensity on the inspection window surface 110 is the above. The irradiation intensity was adjusted. As the LED light source, a 405 nm wavelength LED light source UFSL-501-08UV-UT (manufactured by U-Technology Co., Ltd.) was used, and the distance between the light irradiation unit 21 and the inspection window surface 110 was set to 100 mm. The inspection windows in the test area were cleaned before the start of the test, and the inspection windows cleaned at the same time were used as the control area.

FIG. 13 is a photograph taken in the vicinity of the irradiation area L of the test group where the irradiation intensity was 50 Wm ^-2 8 weeks after the start of the test. FIG. 14 is a photograph of the vicinity of the irradiation region L of the test group in which the irradiation intensity was set to 200 Wm ^-2 8 weeks after the start of the test. FIG. 15 is a photograph of the vicinity of the irradiation region L of the test group in which the irradiation intensity was set to 200 Wm ^-2 38 weeks after the start of the test. FIG. 16 is also a photograph of a control group 38 weeks after the start of the test. In FIG. 13, which shows the test group of 50 Wm ^-2 , the formation of an iron hydroxide film was confirmed in the irradiation region L, but it was very thin and the formation of the iron film was suppressed. In addition, no adhesion of biofilm or the like occurred. In FIG. 14, which shows the test group of 200 Wm ^-2 , the formation of the iron hydroxide film I was confirmed in the irradiation region L. Further, in FIG. 15, which shows the test group of 200 Wm- ² , the formation of a thick yellow iron hydroxide film similar to the irradiation region L of 200 Wm ^-2 in FIG. 10 was confirmed. No attachment of attached organisms or biofilms occurred in the irradiation region L of FIGS. 13 to 16. Barnacles B may have adhered to locations other than the irradiation region L. On the other hand, in FIG. 16 showing the target group, barnacles or periphyton were observed on the entire surface. Therefore, it was confirmed that when the irradiation intensity of the LED light of 405 nm is 50 Wm ^-2 , the adhesion of attached organisms and biofilm can be suppressed, and the adhesion of the film formed by the compound containing iron can be suppressed. Further, it was confirmed that when the irradiation intensity was 200 Wm ^-2 , a thicker iron hydroxide film was formed as compared with the case where the irradiation intensity was 50 Wm- ² .

100 Underwater structure 110 Inspection window surface (window surface)
1, 1a, 1b, 1c Foreign matter adhesion prevention device 20, 20a, 20b, 20c Light emitting part 30, 30a, 30b, 30c Shielding part 35 Lock mechanism 40 Sensor part

Claims (9)

A light emitting part that irradiates the window surface of the underwater structure with the irradiation light,
It has a shielding portion capable of preventing the irradiation light from leaking into the underwater structure.
The irradiation light has a peak in the wavelength range of 405 to 412 nm.
When the divalent iron ion concentration in the water outside the window surface is less than 0.1 mg / L, the irradiation light is light having an irradiation intensity of 25 Wm ^-2 or more.
The irradiation light is light having an irradiation intensity in the range of 25 Wm ^-2 to 100 Wm ^-2 when the divalent iron ion concentration in the water outside the window surface is 0.1 mg / L or more .
The outside of the window surface is an outside of the underwater structure, and is a region including a water passage point of the underwater structure, which is a foreign matter adhesion prevention device. The foreign matter adhesion prevention device according to claim 1, wherein the attachment of the attached organism or biofilm to the window surface is suppressed by the irradiation of the irradiation light. The foreign matter adhesion prevention device according to claim 1 or 2, wherein the adhesion of a film formed of a compound containing iron to the window surface is suppressed by irradiation with the irradiation light. The shielding portion is between a closed state in which the irradiation light is prevented from leaking into the underwater structure and an open state in which the window surface is visible from the inside of the underwater structure. It is provided so that it can be opened and closed.
The foreign matter adhesion prevention device according to any one of claims 1 to 3, wherein the irradiation light is irradiated only in the closed state. The light emitting unit includes a control unit and a sensor unit.
The sensor unit can detect the open state and the closed state, and can detect the open state and the closed state.
When the open state is detected by the sensor unit, the control unit controls to stop the irradiation of the irradiation light.
The foreign matter adhesion prevention device according to claim 4, wherein when the closed state is detected by the sensor unit, the control unit controls to irradiate the irradiation light. The shielding portion has a locking mechanism capable of holding the closed state.
The foreign matter adhesion prevention device according to claim 4 or 5, wherein the lock mechanism holds the closed state when the irradiation light is irradiated, and releases the holding of the closed state when the irradiation light is not irradiated. The foreign matter adhered to any one of claims 1 to 6, wherein the light emitting unit has an LED light emitting panel including a plurality of LED light emitting elements, and irradiates the irradiation light to at least half the area of the window surface. Prevention device. The shielding portion has a conical shape that extends with respect to the window surface.
The foreign matter adhered to any one of claims 1 to 6, wherein the light emitting portion is arranged at the apex portion of the shielding portion having the conical shape and has a point light source that irradiates the window surface with the irradiation light. Prevention device. The foreign matter adhesion prevention device according to any one of claims 1 to 8, wherein the window surface is a window portion for inspection in the underwater structure.

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