Method of suppressing adhesion and propagation, apparatus for suppressing adhesion and propagation, and water quality meter

Abstract

To provide a method of suppressing adhesion and propagation, an apparatus for suppressing adhesion and propagation, and a water quality meter that can efficiently suppress adhesion and / or propagation of adhesion organisms to an object and achieve a longer service life of an irradiation apparatus.SOLUTION: A method of suppressing adhesion and propagation is a method of suppressing adhesion and propagation of adhesion organisms to an object to which adhesion organisms can adhere and suppressing adhesion and propagation of adhesion organisms satisfying conditions represented by the formula (1), and includes intermittent light irradiation to an object. The formula (1) X×a / (a+b)≥Y, where X is a light irradiance (Wm-2), a is a time irradiated with light, b is a time not irradiated with light, and Y is a light irradiance set for each adhesion organism (Wm-2).SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a method for inhibiting adhesion propagation, an apparatus for inhibiting adhesion propagation, and a water quality meter. [Background technology]

[0002] Conventionally, there are known techniques for preventing adhesion of sessile organisms such as barnacles to structures such as water quality meters and seawater system facilities of thermal power plants, nuclear power plants, etc. For example, Patent Document 1 discloses a method for preventing adhesion of sessile organisms to a structure by irradiating the structure in water with light having a wavelength of 409 to 412 nm. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-188570 A Summary of the Invention [Problem to be solved by the invention]

[0004] The method disclosed in Patent Document 1 can suppress the adhesion of sessile organisms to the areas of the structure where light with high irradiance is irradiated. However, there is a possibility that sessile organisms may be attracted to areas where light with low irradiance is irradiated, such as between light irradiation devices or at the ends of the structures, or to areas that are not irradiated and are in the shadows, and there is a problem that the effect of suppressing the adhesion of sessile organisms is insufficient. In addition, the irradiation devices tend to deteriorate due to heat generated by the irradiation of light, and there is room for improvement in terms of extending the life of the irradiation devices.

[0005] The present invention has been made in consideration of the above, and aims to provide an adhesion reproduction inhibition method, an adhesion reproduction inhibition device, and a water quality meter that can efficiently suppress the adhesion of adhesion organisms to an object and achieve a longer lifespan of the irradiation device. [Means for solving the problem]

[0006] (1) The present invention relates to a method for inhibiting adhesion and / or proliferation of sessile organisms on an object to which sessile organisms may adhere, the method satisfying the condition represented by the following formula (1) and intermittently irradiating the object with light. X×a / (a+b)≧Y...Equation (1) where X is the light irradiance (Wm -2 ), a is the time when light is irradiated, b is the time when light is not irradiated, and Y is the irradiance of light set for each attached organism (Wm -2 ).

[0007] (2) The method for inhibiting adhesion propagation described in (1), wherein Y in the formula (1) is 20.

[0008] (3) The method for inhibiting adhesion propagation according to (1), wherein Y in the formula (1) is 150.

[0009] (4) The method for inhibiting adhesion propagation according to any one of (1) to (3), wherein the light irradiated to the object has a peak in a wavelength range of 400 to 430 nm.

[0010] (5) The present invention also relates to an attachment reproduction inhibition device having an irradiation device that irradiates light onto an object and a control unit that controls the irradiation device, wherein the control unit controls the irradiation device so that light is irradiated from the irradiation device to the object intermittently while satisfying the condition expressed by the following formula (1). X×a / (a+b)≧Y...Equation (1) where X is the irradiance of the light from the irradiation device (Wm -2 ), a is the time when light is irradiated from the irradiation device, b is the time when light is not irradiated from the irradiation device, and Y is the irradiance of light (Wm -2 ).

[0011] (6) The present invention also relates to a water quality meter having the attachment propagation inhibition device described in (5) and a sensor device, wherein the irradiation device irradiates light to a detection unit of the sensor device, the light irradiated from the irradiation device has a peak in a wavelength range of 400 to 420 nm, the sensor device performs a detection operation at each predetermined detection timing, and the control unit controls the irradiation device so that light is intermittently irradiated from the irradiation device to the detection unit at each irradiation time other than the predetermined detection timing.

[0012] (7) The water quality meter according to (6), wherein an irradiation surface of the irradiation device is arranged opposite the detection unit. Effect of the Invention

[0013] According to the present invention, it is possible to provide an adhesion propagation inhibition method, an adhesion propagation inhibition device, and a water quality meter that can efficiently inhibit adhesion of adhesion organisms to an object and realize a longer life of an irradiation device. [Brief description of the drawings]

[0014] [Figure 1] 1 is a block diagram showing the configuration of an attachment propagation inhibition device according to one embodiment of the present invention. [Diagram 2] 1 is a diagram showing a configuration of a water quality meter according to a first embodiment of the present invention. [Diagram 3] FIG. 6 is a diagram showing the configuration of a water quality meter according to a second embodiment of the present invention. [Figure 4] FIG. 11 is a diagram showing the configuration of a water quality meter according to a third embodiment of the present invention. [Diagram 5] FIG. 13 is a diagram showing the configuration of a water quality meter according to a fourth embodiment of the present invention. [Figure 6] FIG. 13 is a box plot for the results of juvenile barnacle rate. [Figure 7] This figure shows the phototaxis of cypris larvae under continuous and intermittent (1 / 1, 1 / 2) irradiation conditions with a wavelength of 405 nm and an irradiance of 20 Wm-2. [Figure 8]This is a figure showing the phototaxis behavior of cypris larvae under continuous and intermittent (1 / 1, 1 / 2) irradiation conditions with a wavelength of 405 nm and an irradiance of 400 Wm-2. [Figure 9] This is a figure showing the phototaxis behavior of cypris larvae under continuous and intermittent (1 / 1, 1 / 2) irradiation conditions with a wavelength of 405 nm and an irradiance of 600 Wm-2. [Figure 10] This is a figure showing the phototaxis behavior of cypris larvae under continuous and intermittent irradiation (1 / 1, 1 / 2) conditions with a wavelength of 405 nm and an irradiance of 2000 Wm-2. [Figure 11] This figure shows the phototaxis of cypris larvae under continuous and intermittent irradiation conditions (0.1 / 0.1, 0.1 / 0.2, 0.1 / 0.3) with a wavelength of 405 nm and an irradiance of 600 Wm-2. [Figure 12] This figure shows the phototaxis of cypris larvae under continuous and intermittent (1 / 1, 1 / 2) irradiation conditions with a wavelength of 520 nm and an irradiance of 600 Wm-2. [Figure 13] This figure shows the reaction status of freshwater hydra under each intermittent irradiation condition with an irradiance of 500 Wm-2. [Figure 14] FIG. 1 shows an evaluation of the reaction status of freshwater hydra under each intermittent irradiation condition with an irradiance of 1000 Wm-2. [Figure 15] FIG. 13 is a diagram illustrating an experimental apparatus used in Example 3 of the present invention. [Figure 16] 13 is an image showing a test plate after testing according to Comparative Example 6 of the present invention. [Figure 17] 13 is an image showing a test plate after testing according to Example 3 of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described. Note that the present invention is not limited to the following embodiment and can be appropriately modified.

[0016] <Methods for inhibiting adhesion and propagation> The adhesion and proliferation inhibition method according to this embodiment is a method for inhibiting adhesion of organisms to an object by intermittently irradiating light (hereinafter referred to as intermittent irradiation) to the object to which the adhesion organisms may adhere so as to satisfy a predetermined condition. Note that intermittent irradiation refers to irradiating the object with light by switching between a state in which the object is irradiated with light and a state in which the object is not irradiated with light.

[0017] Examples of the object include structures installed underwater (including structures that are permanently or temporarily wet with liquids such as water or sweat) or structures installed in the air, such as equipment of seawater systems in power generation facilities such as thermal power plants and nuclear power plants, and inspection windows for inspecting these equipment. In addition to the above, the object may be a water quality meter, an underwater camera device, a water intake pipeline, a rotary screen, a bar screen, a drum screen, a mussel filter, a net screen, a water intake pump, a circulating water pump, a circulating water pipe, a heat exchanger, a condenser, a bearing cooling water cooler, a lubricating oil cooler, an LNG vaporizer, a generator, a discharge pipeline, a water wheel, an impeller, a valve, a rotating shaft, a water conveyance pipeline, a filtration tank, a membrane, a dam, a ship, a hull in a shipyard, a ballast water tank, a ballast water inlet / outlet pipe, a pump, an aquaculture facility, a fishery testing facility, a fishery facility, an aquarium, a fish tank in a fish and shellfish breeding tank, a pipe, a pump, a water tank / heat sink of a cooling tower, a scrubber water tank, etc. It may also be, for example, floors of bathrooms, swimming pools, shower rooms, toilets, kitchens, etc. It may also be seats in rooms or cars, operating rooms in hospitals, desks, chairs, exterior and interior walls of buildings, window glass, etc. It may also be the surface or inner surface of a pack container, fresh food, synthetic food, foam, cream, jelly, gel, etc. The structure referred to here may also be a living organism. For example, it may be the shell or soft body of an oyster, fish, protozoa parasitic on fish, plankton, algae, microorganisms, parts of biological tissues, teeth, skin, cells, and their secretions. The structure does not have to be solid. For example, air bubbles in water can also be structures on whose surfaces many attached microorganisms accumulate and adhere. Similarly, liquid droplets in the air can also be structures on which many attached microorganisms accumulate and adhere.

[0018] The sessile organisms that can attach to the above-mentioned objects are not particularly limited as long as they are organisms that have the property of attaching to the surface of underwater structures (including structures that are permanently or temporarily wet with liquids such as water or sweat) or structures in the air, and examples thereof include sessile organisms such as mussels, barnacles, and hydrozoans, and microorganisms such as bacteria, viruses, fungi, blue-green algae, and protozoa. Sessile organisms are organisms that float in the sea during their early larval stages, and when they reach the sessile stage, they attach to a suitable object and metamorphose into adults. In addition, sessile organisms also include microalgae such as sessile diatoms, green algae, brown algae, and red algae, and larvae of sponges, jellyfish, tube-dwelling polychaetes, bryozoans, and amphizoans.

[0019] Mussels are a general term for bivalve mollusks in the family Mytilidae, and include, for example, the subfamily Modiolinae (Modiolinae) such as the larval mussel, the subfamily Lithophaginae (Lithophaginae) such as the lizardfish, the Crenellinae (Crenellinae) such as the Japanese mussel and the Japanese mussel, and the subfamily Mytilinae (Mytilinae) such as the Japanese mussel, the Japanese marsh mussel, and the purple mussel. Barnacles are a general term for those classified into Crustacea, Cirripadia, and Thoracica, including those belonging to the Balanomorpha suborder, which includes, for example, the striped barnacle, the American barnacle, the red barnacle, the triangular barnacle, the giant red barnacle, the Sarasa barnacle, the rock barnacle, the white striped barnacle, and the European barnacle. Hydrozoa are a general term for animals in the Cnidaria phylum, Hydrozoa class, including, for example, the Anthomedusae order, Hydridae family, such as the hydra, freshwater hydra, and green hydra. The epiphytic generation of jellyfish includes the polyps of moon jellyfish and red jellyfish.

[0020] The sessile organisms that may attach to the above-mentioned objects also include biofilms. A biofilm is a structure formed by microorganisms. A biofilm is usually in the form of a membrane and contains extracellular polymeric substances (EPS) such as polysaccharides secreted by microorganisms. A biofilm may also contain microbial remains, excrement, feces, habitats, gene fragments, organic particles, inorganic particles, etc. In addition, when a very thin biofilm is formed on the seat surface or floor surface of a room or a car, food, the surface, inner surface, or internal parts of a pack container, an individual organism, algae, tissue, cell, skin, tooth, etc., this biofilm can be considered as a sessile organism.

[0021] The above-mentioned predetermined condition for intermittent light irradiation in the method for inhibiting adhesion propagation is a condition represented by the following formula (1).

[0022] X×a / (a+b)≧Y...Equation (1) where X is the light irradiance (Wm -2 ), a is the time when light is irradiated (hereinafter referred to as the on-time), b is the time when light is not irradiated (hereinafter referred to as the off-time), and Y is the irradiance of light (Wm -2 In this specification, the on time means the time from when light irradiation of an object starts to when the irradiation stops the next time in intermittent irradiation. The off time means the time from when irradiation stops to when the irradiation starts the next time in intermittent irradiation.

[0023] As Y, an irradiance capable of inhibiting the attachment and / or proliferation of the affixed organisms to the object (hereinafter referred to as attachment and proliferation inhibition) is set according to the type of the affixed organisms. The irradiance as Y (hereinafter referred to as irradiance Y) may be set, for example, according to the resistance of the affixed organisms to light. In this case, the irradiance Y may be set to the same value for a plurality of affixed organisms having different resistances to light, or different values ​​may be set for each. When the irradiance Y is set to the same value, an irradiance Y effective for inhibiting the attachment and proliferation of the affixed organisms having the highest resistance to light may be set. In this embodiment, the same value is set regardless of the type of the affixed organisms. By using the above formula (1), the light emission conditions for inhibiting attachment and proliferation can be easily set.

[0024] In this embodiment, the irradiance Y in equation (1) is, for example, 20 Wm -2 is preferred, and 150Wm -2 It is more preferable that the irradiance Y in formula (1) is 20 Wm -2 By adjusting the light irradiance X, the light-on time a, and the light-off time b so that the attachment and / or proliferation of the attached organisms on the target object can be suppressed. -2 By adjusting the irradiance X of the light, the on time a, and the off time b so that the adhesion and / or proliferation of the sessile organisms on the target object can be almost completely suppressed. Note that the irradiance in this specification refers to the value of the irradiance measured by an Ophir StarLite-PD300RM-8W irradiance meter.

[0025] The lighting time a and the extinguishing time b are not particularly limited as long as they satisfy the condition of formula (1). For example, the lighting time a may be less than 0.1 seconds, 0.1 seconds or more, 1.0 seconds or more, 1.0 minutes or more, or 1 hour or more. For example, the extinguishing time b may be less than 0.1 seconds, 0.1 seconds or more, 1.0 seconds or more, 1.0 minutes or more, or 1 hour or more. That is, as long as formula (1) is satisfied, the lighting time a / (lighting time a+extinguishing time b) can be freely set. For example, the lighting time a / (lighting time a+extinguishing time b) may be 0.1 or 99.9.

[0026] The irradiance X of the light is not particularly limited as long as it satisfies the condition of formula (1). The irradiance X is, for example, 20 Wm -2 More than 50Wm is preferable. -2 More preferably, it is 100Wm -2 More preferably, it is equal to or greater than this.

[0027] By irradiating light intermittently and so as to satisfy the condition of the above-mentioned formula (1), the adhesion and / or proliferation of sessile organisms can be more reliably and efficiently suppressed, and the adhesion of foreign matter to the object irradiated with light can be more preferably suppressed than by irradiating light continuously. In detail, when irradiating light continuously, foreign matter such as sessile organisms do not adhere to the area irradiated with strong light, but sessile organisms may be attracted by phototaxis to the peripheral area of ​​the light axis irradiated with relatively weak light, and the sessile organisms may proliferate. By irradiating the object with light intermittently, the attraction of sessile organisms by phototaxis can be suppressed, and the adhesion and / or proliferation of sessile organisms can be efficiently suppressed. In addition, by irradiating the object with light intermittently from an irradiation device such as the irradiation device 20 described later, the deterioration over time of the LED elements of the irradiation device is suppressed, and the durability of the irradiation device can be improved. Therefore, the life of the irradiation device can be extended.

[0028] The light irradiated to the object preferably has a peak in the wavelength range of 400 to 430 nm. Although ultraviolet light having a wavelength of 380 nm or less has an effect of inhibiting adhesion and proliferation of attached organisms, it has a problem of low transmittance in seawater. By setting the wavelength of the irradiated light within the above range, a preferable effect of inhibiting adhesion and proliferation and an effect of removing attached organisms can be obtained. The wavelength of the irradiated light may have a peak in a wavelength range other than the above range, as long as it does not impair the effects of the present invention. For example, the wavelength of the irradiated light may have a peak in the wavelength range of 430 to 490 nm, or may have a peak in the wavelength range of 490 nm to 550 nm.

[0029] Next, an example of an apparatus capable of suppressing adhesion or proliferation of adhesion organisms on an object using the adhesion and proliferation suppression method will be described.

[0030] <Attachment and propagation suppression device> First, the adhesion and reproduction inhibition device 1 will be described with reference to Fig. 1. The adhesion and reproduction inhibition device 1 includes an irradiation device 20 that irradiates a target object with light, and a control unit 5 that controls the irradiation device 20, as shown in Fig. 1.

[0031] The irradiation device 20 is, for example, an LED irradiation device, and is configured to include one or more LED elements. The irradiation device 20 is connected to the control unit 5 so as to be able to communicate with each other.

[0032] The light irradiated by the irradiation device 20 preferably has a peak in a wavelength range of 400 to 430 nm. The wavelength of the irradiated light may have a peak in a wavelength range other than the above range, as long as the effect of the present invention is not impaired. For example, the wavelength of the irradiated light may have a peak in a wavelength range of 430 to 490 nm, or may have a peak in a wavelength range of 490 nm to 550 nm.

[0033] The control unit 5 is a calculation device configured with a processor such as a CPU, and reads and executes various preset programs and data to control the irradiation device 20. The control unit 5 controls the irradiation device 20 so that the irradiation device 20 irradiates the object with light intermittently while satisfying the condition expressed by the above formula (1), thereby suppressing the adhesion of attached organisms to the object. That is, the irradiation device 20 irradiates intermittently so as to satisfy the condition of the above formula (1).

[0034] The irradiance X of the light irradiated from the irradiation device 20 is not particularly limited as long as it satisfies the condition of formula (1). For example, the irradiance X is set to 25 Wm -2 More than 50Wm is preferable. -2 More preferably, it is 100Wm -2 More preferably, it is equal to or greater than this.

[0035] <Water quality meter> Next, the water quality meter will be described with reference to Figs. 2 to 5. The water quality meter according to this embodiment is used to continuously measure the water quality of water in environments such as the ocean, rivers, or lakes for a predetermined period of time, for example, one day or more. Examples of water quality measurement items measured by the water quality meter include water temperature, salinity, dissolved oxygen (DO) concentration, chlorophyll, organic matter, turbidity, illuminance, pH, ORP (oxidation-reduction potential), conductivity, specific gravity, depth, flow direction and flow velocity, various ion concentrations, visible light and / or infrared light images, etc. The water quality meter according to this embodiment may be capable of measuring a plurality of the above water quality measurement items.

[0036] The water quality meter according to this embodiment includes a sensor device as an object, an illumination device that illuminates the detection unit of the sensor device with light, and a control unit that controls the illumination device. The combined configuration of the illumination device and control unit of the water quality meter corresponds to an adhesion proliferation inhibition device 10.

[0037] First Embodiment The water quality meter 1 according to this embodiment is a water temperature / salinity meter having a salinity concentration sensor (detection unit 31) as a sensor device and a water temperature sensor (detection unit 32), as shown in Fig. 2. In addition to the above, the water quality meter 1 also includes irradiation devices 20a and 20b, a main body unit 4, a control unit 5, and a support body 7a.

[0038] (irradiation device) The irradiation devices 20a and 20b intermittently irradiate the detection unit 31 of the salinity concentration sensor and the detection unit 32 of the water temperature sensor with light having a peak in the wavelength range of 400 to 430 nm. This suppresses the adhesion of organisms to the detection unit 31 of the salinity concentration sensor and the detection unit 32 of the water temperature sensor. The irradiation devices 20a and 20b are, for example, LED irradiation devices and are configured to include one or more LED elements. The irradiation devices 20a and 20b have housing parts 21a and 21b and irradiation surfaces 22a and 22b, respectively. The irradiation surface 22a is arranged opposite one opening 31a of the hole in which the detection unit 31 of the salinity concentration sensor is arranged, and the detection unit 32 of the water temperature sensor. The irradiation surface 22b is arranged opposite the other opening 31b of the hole in which the detection unit 31 of the salinity concentration sensor is arranged.

[0039] The attached organisms that may attach to the detection unit are not particularly limited as long as they are organisms that have the property of attaching to the surface of an object placed in water, but examples include microorganisms such as mussels, barnacles, hydrozoans, and marine bacteria, as well as biofilms.

[0040] The light emitted from the irradiation devices 20a and 20b has a peak in the wavelength range of 400 to 430 nm. The wavelength of the irradiation light may include wavelength ranges other than the above range as long as the effect of the present invention is not impaired. For example, the wavelength range of the irradiation light may include light in the wavelength range of 400 to 440 nm.

[0041] The irradiance of the light irradiated from the irradiation devices 20a and 20b is set to 25 Wm from the viewpoint of suppressing the adhesion of attached organisms. -2 More than 50Wm is preferable. -2 More preferably, it is 100Wm -2More preferably, it is equal to or greater than this.

[0042] By intermittently irradiating light from the irradiation devices 20a and 20b, adhesion of foreign matter to the detection unit 31 and the detection unit 32 to which light is irradiated can be more effectively suppressed than by continuous light irradiation. In detail, when light is irradiated continuously, foreign matter such as attached organisms does not adhere to the area irradiated with strong light, but attached organisms such as algae that grow by photosynthesis may easily grow in the peripheral area of ​​the optical axis irradiated with relatively weak light. This is considered to be because the light irradiated from the irradiation devices 20a and 20b contains wavelengths of light effective for photosynthesis. The intermittent irradiation of light from the irradiation devices 20a and 20b suppresses the growth of algae. Although the reason for the above is unclear, it is considered that the intermittent irradiation of light causes an insufficient amount of light for photosynthesis of algae, inhibiting their growth.

[0043] The intermittent irradiation of light from the irradiation devices 20a and 20b has the effect of suppressing adhesion of algae and the like to the irradiation surfaces 22a and 22b of the irradiation devices 20a and 20b. When the irradiation devices 20a and 20b are configured to include a plurality of LED elements and light is continuously irradiated from the irradiation devices 20a and 20b, algae and the like may adhere between the plurality of LED elements, resulting in a decrease in the irradiance of the irradiated light. However, by intermittently irradiating light from the irradiation devices 20a and 20b, even when the irradiation devices 20a and 20b include a plurality of LED elements, it is possible to suppress a decrease in the irradiance of the irradiated light. In addition, the intermittent irradiation of light from the irradiation devices 20a and 20b suppresses deterioration over time of the LED elements, thereby improving the durability of the water quality meter 1.

[0044] (Sensor device) The salinity sensor is a sensor device that detects the salinity in water. The detection unit 31 of the salinity sensor is provided in a hole through which liquid can flow. If the flow of liquid such as seawater is hindered due to the adhesion of attached organisms to the hole, the salinity sensor cannot accurately measure the salinity. The light irradiated from the irradiation devices 20a and 20b of the water quality meter 1 according to this embodiment suppresses the attachment of attached organisms not only to the detection unit 31 but also to the hole in which the detection unit 31 is placed. This allows the salinity sensor to continuously and accurately measure the salinity.

[0045] The water temperature sensor is a sensor device that detects water temperature. The light irradiated from the irradiation device 20a to the detection unit 32 of the water temperature sensor suppresses the adhesion of organisms to the detection unit 32. This allows the water temperature sensor to continuously and accurately measure the water temperature.

[0046] The salinity concentration sensor and the water temperature sensor as the sensor device are set to perform a detection operation at each predetermined detection timing. The detection interval for performing the above detection is not particularly limited, but may be, for example, 10 minutes or more so that the detection result of the sensor device is not affected by residual heat due to the light irradiated from the irradiation device. The detection interval may be one day. It is preferable that the predetermined detection timing of the salinity concentration sensor and the water temperature sensor is the same timing.

[0047] (Main body) The main body 4 houses a salinity concentration sensor and a water temperature sensor. In addition to the above, the main body 4 may include a storage unit that stores the results of measurement by the salinity concentration sensor and the water temperature sensor.

[0048] (Control unit) The control unit 5 controls the irradiation timing of the irradiation devices 20a and 20b so that light is intermittently emitted from the irradiation devices 20a and 20b. The control unit 5 is communicatively connected to the irradiation devices 20a and 20b by wirings 6a and 6b, respectively.

[0049] The control unit 5 controls the irradiation devices 20a and 20b to irradiate light to the detection unit 31 of the salinity sensor and the detection unit 32 of the water temperature sensor at each irradiation time other than the predetermined timing at which the salinity sensor and the water temperature sensor perform the detection operation. When the salinity sensor and the water temperature sensor perform the detection operation while the irradiation devices 20a and 20b are irradiating the detection unit 31 and the detection unit 32 with light, the salinity sensor and the water temperature sensor may not be able to perform accurate measurement. However, with the above configuration, the control unit 5 controls the irradiation devices 20a and 20b not to irradiate light to the detection unit 31 and the detection unit 32 while the salinity sensor and the water temperature sensor are performing the detection operation. This allows the salinity sensor and the water temperature sensor to perform accurate measurement. From the viewpoint of performing accurate measurement, it is preferable that the predetermined timing at which the salinity sensor and the water temperature sensor perform the detection operation is the center timing of the time when the irradiation devices 20a and 20b do not irradiate light.

[0050] It is preferable that the control unit 5 controls the irradiation devices 20a and 20b so that the ratio of the irradiation time during which the irradiation devices 20a and 20b irradiate the detection units 31 and 32 with light is 30 to 70% of the total of the irradiation time and the time during which the irradiation devices 20a and 20b do not irradiate light (i.e., the elapsed time). This provides an effect of preventing adhesion of foreign matter such as attached organisms, and can suppress adhesion of algae to the areas irradiated with relatively weak light.

[0051] For example, when the detection interval of the sensor device is 20 minutes and the ratio of the irradiation time is 50%, the control unit 5 causes the irradiation devices 20a and 20b to irradiate light to the detection units 31 and 32 5 minutes after the detection timing of the sensor device. Light is continuously irradiated from the irradiation devices 20a and 20b during the irradiation time of 10 minutes. When the irradiation time of 10 minutes has elapsed, the control unit 5 stops the irradiation of light from the irradiation devices 20a and 20b. After that, the detection timing of the next sensor device arrives after 5 minutes has elapsed, and the sensor device performs a detection operation. This can eliminate the influence on the detection of the sensor device, such as a rise in water temperature caused by the irradiation of light from the irradiation devices 20a and 20b.

[0052] (Support) The support 7a is a support for fixing the irradiation devices 20a and 20b, and is configured to allow water from the outside to pass through the detection units 31 and 32. The support 7a has, for example, a frame shape, and is not particularly limited in terms of material, and materials such as metal and resin can be used appropriately. The support 7a allows the irradiation surfaces 22a and 22b to be arranged so as to face the detection units 31 and 32.

[0053] Hereinafter, other embodiments of the present invention will be described. Descriptions of configurations similar to those of the first embodiment will be omitted in some cases.

[0054] Second Embodiment 3, the water quality meter 1a according to the second embodiment has a dissolved oxygen (DO) concentration sensor (detection unit 33) as a sensor device and a water temperature sensor (detection unit 34). In addition to the above, the water quality meter 1a also has an irradiation device 20c, a main body unit 4a, a control unit 5a, a support body 7b, and a wiper device 8.

[0055] The irradiation device 20c according to this embodiment has a housing part 21c and an irradiation surface 22c. In this embodiment, the irradiation device 20c is a single irradiation device, and the irradiation surface 22c is disposed facing a detection part 33 of a dissolved oxygen (DO) concentration sensor and a detection part 34 of a water temperature sensor. The irradiation device 20c is fixed and supported by a support body 7b. The support body 7b has a frame shape similar to the support body 7a.

[0056] The dissolved oxygen (DO) concentration sensor is a sensor device that measures the dissolved oxygen (DO) concentration in water. The detection unit 33 of the dissolved oxygen (DO) concentration sensor and the detection unit 34 of the water temperature sensor are intermittently irradiated with light having a peak in the wavelength range of 400 to 430 nm from the irradiation device 20c, thereby suppressing adhesion of attached organisms to the detection unit 33 and the detection unit 34. The configuration in which the detection timing of the dissolved oxygen (DO) concentration sensor and the water temperature sensor, and the irradiation timing at which light is irradiated from the irradiation device 20c are controlled by the control unit 5a is the same as that of the water quality meter 1 according to the first embodiment. The control unit 5a is housed inside the main body unit 4a and is communicably connected to the irradiation device 20c by a wiring 6c.

[0057] (Wiper device) The wiper device 8 is a device that removes by wiping off the attached organisms that adhere to the detection unit 33 of the dissolved oxygen (DO) concentration sensor and the detection unit 34 of the water temperature sensor. The wiper device 8 has abutting parts that rotatably come into contact with the detection units 33 and 34. The abutting parts are made of a flexible material such as resin. Since the water quality meter 1a has the wiper device 8 in addition to the irradiation device 20c, even if one device is unable to sufficiently inhibit or remove the attachment and proliferation of attached organisms to the detection units 33 and 34 due to a malfunction of the device, the other device can inhibit or remove the attachment and proliferation of attached organisms to the detection units 33 and 34, so that the sensor device can perform accurate measurement more reliably.

[0058] Third Embodiment 5, the water quality meter 1c according to the third embodiment has a pH / ORP sensor (detection unit 36) as a sensor device, a chlorophyll / turbidity sensor (detection unit 37), and a depth sensor (detection unit 38). In addition to the above, the water quality meter 1c also has an irradiation device 20e, a main body unit 4c, and a control unit 5c.

[0059] The irradiation device 20e according to this embodiment has a housing part 21e and an irradiation surface 22e. In this embodiment, the irradiation device 20e is a single irradiation device, and the irradiation surface 22e is disposed facing the detection unit 36 ​​of the pH / ORP sensor, the detection unit 37 of the chlorophyll / turbidity sensor, and the detection unit 38 of the depth sensor. The irradiation device 20e is fixed and supported by a support 7c. The support 7c has a frame shape similar to the support 7a.

[0060] The pH / ORP sensor is a sensor device that measures the hydrogen ion exponent and oxidation-reduction potential (ORP) in water. The chlorophyll / turbidity sensor is a sensor device that measures the chlorophyll concentration and turbidity in water. The depth sensor is a sensor device that measures the depth from the water surface.

[0061] The light having a peak in the wavelength range of 400 to 430 nm is intermittently irradiated from the irradiation device 20e to the detection unit 36 ​​of the pH / ORP sensor, the detection unit 37 of the chlorophyll / turbidity sensor, and the detection unit 38 of the depth sensor, thereby suppressing adhesion of attached organisms to the detection units 36, 37, and 38. The configuration in which the detection timing of the pH / ORP sensor, the chlorophyll / turbidity sensor, and the depth sensor, and the irradiation timing at which the irradiation device 20e irradiates light are controlled by the control unit 5c is the same as that of the water quality meter 1 according to the first embodiment. The control unit 5c is housed inside the main body 4c, and is communicatively connected to the irradiation device 20e by a wire 6e.

[0062] Next, an example in which the adhesion propagation inhibition method according to this embodiment is applied to an underwater camera device will be described. As shown in Fig. 4, the underwater camera device 1b has an illuminance sensor (detection unit 35) as a sensor device. In addition to the above, the underwater camera device 1b also has an illumination device 20d, a main body unit 4b, a control unit 5b, a wiper device 8a, and an imaging unit (camera lens 9).

[0063] The underwater camera device 1b can periodically capture underwater images using an imaging unit. The underwater images are, for example, visible light images. The underwater camera device 1b is equipped with a plurality of irradiation devices 20d around the camera lens 9. The irradiation devices 20d can irradiate light having a peak in the wavelength range of 400 to 430 nm, and preferably can irradiate white light.

[0064] The on time a and off time b of the light having a peak in the wavelength range of 400 to 430 nm irradiated from the irradiation device 20d are not particularly limited as long as they satisfy the condition of formula (1). That is, as long as formula (1) is satisfied, the control unit 5b can freely set the on time a / (on time a+off time b). For example, the on time a / (on time a+off time b) may be set to 0.1 or 99.9.

[0065] The light may be used as illumination by irradiating the light from the irradiation device 20d in accordance with the image capturing timing of the imaging unit. For example, when the ambient illuminance is low at the image capturing timing of the imaging unit, white light is irradiated from the irradiation device 20d, and an image including color information of the object to be captured can be obtained by irradiating the white light as illumination.

[0066] When the ambient illuminance is low at the time of photographing by the imaging unit, if light having a peak in the wavelength range of 400 to 430 nm is irradiated from the illumination device 20d, since the light having a peak in the wavelength range of 400 to 430 nm has a wavelength range that is highly transparent in the sea, an underwater image of a relatively distant area can be photographed.

[0067] In this embodiment, a plurality of irradiation devices 20d (seven in this embodiment) are provided around the camera lens 9.

[0068] The illuminance sensor (detection unit 35) measures the illuminance of the surroundings, and turns on the illumination from the irradiation device 20d under conditions where the illuminance of the surroundings is lower than a predetermined value (dark conditions).

[0069] Next, another example of application of the adhesion reproduction inhibition method according to the present embodiment will be described. In the above-mentioned example of application to an underwater camera device, adhesion reproduction inhibition was performed using the illumination device 20 that intermittently irradiates light, but adhesion reproduction inhibition may also be performed using a device that continuously irradiates light (hereinafter referred to as continuous illumination).

[0070] For example, with the irradiation device fixed, light is continuously irradiated onto the blades of a rotating propeller. At this time, instead of irradiating the entire propeller with light from the irradiation device, the position of the propeller and the direction of light irradiation are fixed, and light is irradiated so that some of the propeller blades are irradiated with light, so that each blade of the propeller can be intermittently irradiated while the irradiation device is performing continuous irradiation. Then, by adjusting the rotation speed of the propeller and the irradiance of the light from the irradiation device to satisfy the above-mentioned formula (1) and performing continuous irradiation, the adhesion of attached organisms can be efficiently suppressed.

[0071] For example, a large structure such as a ship at anchor may be continuously irradiated with light by mounting an irradiation device on a drone or the like and moving the device to scan the ship. In this case, the same effect as intermittent irradiation can be achieved by moving the irradiation device so that the same part of the ship is periodically irradiated with light. Then, by adjusting the irradiance from the irradiation device and the moving speed of the irradiation device to satisfy the condition expressed by formula (1) and irradiating continuously, the adhesion of the attached organisms can be efficiently suppressed. In addition, for example, under a transitory seawater flow condition, high-intensity light is irradiated upstream, and then adhesion is suppressed for a certain period of time in the downstream area, and adhesion is restored after the water is drained, so that the damage caused by biological adhesion within the facility can be efficiently suppressed without affecting the environment. Such an irradiation method can also be considered as a kind of intermittent irradiation. EXAMPLES

[0072] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the description of the following examples.

[0073] [Adhesion suppression effect confirmation test 1] The effectiveness of LED light in inhibiting the adhesion of living organisms was confirmed using cypris larvae of the striped barnacle (hereafter referred to as cypris larvae). Note that cypris larvae are nauplius larvae in the planktonic stage that undergo repeated molting and grow to be able to attach to objects. The juvenile barnacles described below are barnacles that metamorphose after cypris larvae attach to objects such as test containers.

[0074] A test container (a petri dish with a diameter of 6 cm and a height of 6 cm) was filled with 70 ml of test seawater (seawater filtered through a membrane with a pore size of 0.45 μm) and cypris larvae (number of individuals: 44 ± 12, irradiance 1200 Wm -2 In the test area, 30±5 mm of barnacles were placed in the test area. LED light (peak wavelength: 405 nm) was irradiated through the glass lid to the test container under each irradiation condition shown in Tables 1 to 3 below. UFL-501-08 UV-UT (manufactured by U-Technology Co., Ltd.) was used as the light source of the LED light. In order to prevent the temperature of the test seawater, etc. from increasing due to the irradiation of the LED light, the outside of the bottom of the test container was immersed in tap water during the test. The test container was covered with aluminum foil and kept in almost constant darkness without irradiating the LED light as the control area. The test was conducted for 96 hours, and the juvenile barnacle rate was compared between the control area and each test area. The juvenile barnacle rate is the ratio of juvenile barnacles to the number of Barnacles nigricans present in each test container.

[0075] [Table 1]

[0076] [Table 2]

[0077] [Table 3]

[0078] (Test Results) Table 1 shows the irradiance of 100 Wm -2 Continuous irradiation, irradiance 200Wm -2 Continuous irradiation, irradiance 200Wm -2 Table 2 shows the percentage of juvenile barnacles in the test and control areas with intermittent illumination (0.2 sec on / 0.1 sec off, 0.1 sec on / 0.1 sec off, 0.1 sec on / 0.2 sec off). -2 Intermittent irradiation (0.1 seconds on / 0.1 seconds off), irradiance 600Wm -2 Table 3 shows the percentage of juvenile barnacles in the test area and the control area with intermittent irradiation (0.1 seconds on / 0.2 to 1.1 seconds off). -2 Intermittent irradiation (5 minutes on / 10 minutes off), irradiance 1200Wm -2 The figures show the percentage of juvenile barnacles in the test area with intermittent illumination (12 minutes on / 60 minutes off) and the control area. The N number in Table 1 refers to the number of tests (same for the following tables).

[0079] As shown in Table 1, when the irradiance is 200 Wm -2 It was confirmed that the 0.1 second on / 0.1 to 0.2 second off illumination conditions significantly reduced barnacle attachment compared to the control area. Under the continuous illumination and 0.2 second on / 0.1 second off illumination conditions, none of the very few attached barnacles were observed to creep, confirming that attachment to the test containers could be almost completely suppressed.

[0080] As shown in Table 2, the irradiance is 400 Wm -2 Irradiation conditions of 0.1 seconds on / 0.1 seconds off and irradiance of 600Wm -2 Under the irradiation conditions of 0.1 seconds on / 0.2 seconds off, none of the very few attached individuals were observed to move their legs, and it was confirmed that attachment to the test container could be almost completely suppressed. -2It was confirmed that under the illumination condition of 0.1 seconds on / 1.1 seconds off, barnacle attachment could be suppressed by about 0.4% compared to the control area. Under other illumination conditions, it was confirmed that barnacle attachment could be significantly reduced compared to the control area.

[0081] As shown in Table 3, the irradiance is 600 Wm -2 Irradiation conditions: 5 minutes on / 10 minutes off, and irradiance of 1200Wm -2 Under the illumination conditions of 12 minutes on / 60 minutes off, none of the very few attached individuals were observed to crawl, confirming that attachment to the test container could be almost completely suppressed.

[0082] As shown in Tables 1 to 3, the irradiance is 200 Wm -2 The rate of young barnacles (0.5±1.3%) under continuous irradiation at an irradiance of 400Wm -2 Rate of young barnacles (0.5±1.2%) at 0.1 sec on / 0.1 sec off, irradiance 600Wm -2 The rate of young barnacles (0.9±1.6%) at 0.1 sec on / 0.2 sec off, irradiance 600Wm -2 The rate of young barnacles (0.7±1.0%) at 5 min on / 10 min off and irradiance of 1200 Wm -2 The results were very similar for the juvenile barnacle rate (1.8±2.7%) at 12 min on / 60 min off. -2 The rate of young barnacles (7.5±5.8%) under continuous irradiation at an irradiance of 600Wm -2 The results were very similar for the percentage of juvenile barnacles (7.5±6.5%) under the 0.1 s light on / 0.5 s off condition.

[0083] (Significant difference to test results) Here, a significant difference test was conducted on the results of the juvenile barnacle ratio under each irradiation condition in the adhesion suppression effect confirmation test 1 using the statistical software R for multiple comparison tests (Tukey HSD method). Figure 6 is a box plot of the results of the juvenile barnacle ratio under each irradiation condition. The horizontal axis of Figure 6 shows each irradiation condition in the adhesion suppression effect confirmation test 1, and the vertical axis shows the juvenile barnacle ratio (%). Note that A1 is the ratio of juvenile barnacles under an irradiance of 200 Wm-2 Continuous irradiation, A2 is irradiance 400Wm -2 Intermittent illumination of 0.1 seconds on / 0.1 seconds off, A3 has an irradiance of 600Wm -2 Intermittent illumination of 0.1 seconds on / 0.2 seconds off, A4 has an irradiance of 600Wm -2 Intermittent illumination of 5 minutes on / 10 minutes off, A5 has an irradiance of 1200Wm -2 Intermittent illumination of 12 minutes on / 60 minutes off, B1 has an irradiance of 100Wm -2 Continuous irradiation, B2 has an irradiance of 600Wm -2 This shows intermittent illumination with the light on for 0.1 seconds and off for 0.5 seconds.

[0084] As a result of the significance test, no significant difference was found between the results of each juvenile barnacle rate in A1 to A5 (p value > 0.05, p value 0.26 to 0.99).Similarly, no significant difference was found between the results of each juvenile barnacle rate in B1 and B2 (p value > 0.05, p value 0.99).

[0085] From the results of the juvenile barnacle rate and the significant difference test between A1 to A5 and B1 and B2, it can be confirmed that the radiation conditions required for adhesion suppression in each intermittent irradiation are proportional to the irradiation energy. In other words, it was confirmed that the radiation conditions required for adhesion suppression in intermittent irradiation satisfy the above-mentioned equation (1).

[0086] Here, the irradiance is 20 Wm -2 Continuous irradiation (peak of light wavelength: 400-430 nm) can suppress the attachment and / or reproduction of barnacle larvae to the target object, and the irradiance is 150 Wm ―2 It has been found that continuous irradiation with light (peak of light wavelength: wavelength region of 400 to 430 nm) can almost completely suppress the attachment of barnacle larvae to an object. Using these findings, for example, the light irradiation conditions required to prevent the attachment of barnacles when light (peak of light wavelength: wavelength region of 400 to 430 nm) is intermittently irradiated can be calculated using the following formula (2) or formula (3).

[0087] X×a / (a+b)≧20...Equation (2) X×a / (a+b)≧150...Equation (3)

[0088] [Phototaxis confirmation test] The phototaxis of cypris larvae was confirmed. Except for the LED light irradiation conditions, the same procedure as in adhesion suppression effect confirmation test 1 was used to irradiate LED light (peak wavelength: 405 nm) continuously for 96 hours on the cypris larvae in the test container. -2 and 50Wm -2 The tests were conducted under two irradiance conditions:

[0089] (Test Results) Table 4 shows the irradiance of 20 Wm -2 Table 5 shows the distribution of barnacles attached to the petri dishes in the test and control areas. -2 1 is a table showing the location distribution of barnacles attached to the petri dishes in the test plot and the control plot.

[0090] [Table 4]

[0091] [Table 5]

[0092] As shown in Tables 4 and 5, the irradiance is 20 Wm -2 and irradiance 50Wm -2 Under both conditions, in the control area, approximately 80% of the individuals attached to the bottom of the petri dish, and approximately 20% attached to the side of the dish. On the other hand, in the test area, it was confirmed that the difference in the attachment rate between the bottom and side of the petri dish was small. A multiple comparison test (Bonferroni method) was conducted on the side attachment rate in the control area and the side attachment rate in the test area, and it was confirmed that the side attachment rate of the petri dish in the test area was significantly higher (p<0.01). From this result, it is inferred that even when attaching, cypris larvae tend to avoid places where they are directly exposed to LED light (peak wavelength: 405 nm).

[0093] [Test to confirm the effect on phototaxis] Using the cypris larvae of the barnacle Acanthurus anguinus, we investigated the effect of LED light on the swimming behavior of the cypris larvae.

[0094] A test tank (width 1 cm x height 1 cm x length 12 cm) was filled with 20 ml of test seawater (seawater filtered through a membrane with a pore size of 0.45 μm), and a light source was placed at one end of the length of the test tank to irradiate LED light horizontally into the test tank. As light sources, UFL-501-08 UV-UT (U-Technology Co., Ltd.) (peak wavelength: 405 nm) and UFL-501-08 G-UT (U-Technology Co., Ltd.) (peak wavelength: 520 nm) were used. The test tank was numbered from 1 to 24 as lane numbers at 5 mm intervals in ascending order from the end of the light source side in the length direction. A cypris larva was placed in lane 12 of the test tank filled with test seawater, and LED light was irradiated from the light source under each irradiation condition. The irradiation conditions will be described later. One minute after the start of irradiation, it was confirmed which lane the cypris larva had moved to. Fifteen cypris larvae were used in each test, and five cypris larvae were placed in each test tank and observed three times. This test was repeated three times for each illumination condition. In other words, a total of 45 cypris larvae were tested under each illumination condition.

[0095] (Irradiation conditions) The LED light irradiation conditions are a wavelength peak of 405 nm or a wavelength peak of 520 nm, and an irradiance of 20 Wm ―2 , 400Wm ―2 , 600Wm ―2 , or 2000Wm ―2 The phototaxis of cypris larvae was confirmed by continuous irradiation or the following intermittent irradiation under conditions of each combination of wavelength and irradiance. <Intermittent irradiation conditions> If the lighting time (seconds) is set to lighting time (seconds) / light-off time (seconds), there are five conditions: 0.1 / 0.1, 0.1 / 0.2, 0.1 / 0.3, 1 / 1, and 1 / 2.

[0096] (Test Results) The results of this test are shown in Figures 7 to 12. The horizontal axis of Figures 7 to 12 is the lane number of the test tank in which cypris larvae were confirmed one minute after the start of irradiation, and the vertical axis is the average number of cypris larvae that moved to each lane number over three tests.

[0097] 7 to 11 show the test results for radiation conditions at a wavelength of 405 nm, and FIG. 12 shows the test results for radiation conditions at a wavelength of 520 nm. ―2 The irradiation conditions of continuous irradiation and intermittent irradiation (1 / 1, 1 / 2) are shown in Fig. 8. The irradiance is 400 Wm ―2 The irradiation conditions of continuous irradiation and intermittent irradiation (1 / 1, 1 / 2) are shown in Fig. 9. The irradiance is 600 Wm ―2 The irradiation conditions are continuous irradiation and intermittent irradiation (1 / 1, 1 / 2). Figure 10 shows the irradiance of 2000Wm ―2 The irradiation conditions for continuous irradiation and intermittent irradiation (1 / 1, 1 / 2) are shown in Figure 11. The irradiance is 600 Wm ―2 The irradiation conditions are continuous irradiation and intermittent irradiation (0.1 / 0.1, 0.1 / 0.2, 0·1 / 0.3). Figure 12 shows the irradiation conditions of 600Wm ―2 The irradiation conditions are continuous irradiation and intermittent irradiation (1 / 1, 1 / 2).

[0098] As shown in Figures 7 to 11, it was confirmed that continuous irradiation with LED light of a wavelength of 405 nm caused the cypris larvae to tend to approach the light source and to swim in the opposite direction to the light source. ―2 In the case of continuous illumination, clear repellent and escape behavior was observed, with the larvae swimming in the opposite direction to the light source. On the other hand, in the case of intermittent illumination, it was confirmed that the number of individuals attracted to the light source was reduced compared to continuous illumination, and that the number of individuals escaping from the light source in the opposite direction to the light source tended to decrease. From these results, it is inferred that intermittent illumination suppresses the movement of cypris larvae due to phototaxis in response to light illumination.

[0099] As shown in Figure 12, it was confirmed that continuous illumination at a wavelength of 520 nm caused many larvae to swim toward the light source. On the other hand, in the case of intermittent illumination, it was confirmed that fewer individuals approached the light source compared to continuous illumination. In other words, it is presumed that intermittent illumination suppresses the attraction of cypris larvae to light with a wavelength of 520 nm due to their phototaxis.

[0100] [Adhesion suppression effect confirmation test 2] The effect of light irradiation on the adhesion of hydroids was confirmed using stem segments of the hydroid Hydra spp. The stem segments were prepared by cutting off the roots and flowers of the hydroid Hydra spp. after isolating the polyps from a colony of the hydroid Hydra spp.

[0101] 70 ml of test seawater (seawater filtered through a membrane with a pore size of 0.45 μm) and Hydra stem pieces (number of pieces: 12 pieces) were placed in a test container (a glass petri dish with a diameter of 6 cm and a height of 6 cm). As a test group, this test container was irradiated with LED light (peak wavelength: 405 nm) through a glass lid under each irradiation condition shown in Tables 4 and 5 below. As a control group, the test container was covered with aluminum foil and kept in almost constant darkness without irradiating with LED light. The test was conducted for 96 hours, and the regeneration rate of Hydra stem pieces and the number of regenerated Hydra flowers were compared between the control group and each test group.

[0102] [Table 6]

[0103] [Table 7]

[0104] (Test Results) Table 6 shows the irradiance of 200 Wm -2 Table 7 shows the regeneration rate and number of regenerated Hydra flowers in the test and control plots after 96 hours under the intermittent illumination condition (1 hour on / 1 hour off). -2The regeneration rate of Hydra stem segments and the number of regenerated Hydra flowers after 96 hours in the test and control areas under the intermittent illumination condition (2 hours on / 2 hours off) are shown in Tables 6 and 7. -2 In the two intermittent irradiation conditions, the regeneration rate of the Hydra stem segments and the number of regenerated Hydra flowers after 96 hours were confirmed to be 0%. During the test, it was also observed that the stem tissue of the Hydra gradually regressed and collapsed from the cut part. From these results, it was found that the regeneration rate of the Hydra stem segments and the number of regenerated Hydra flowers after 96 hours were 0%. -2 It was confirmed that colony formation of marine hydrozoans can be completely suppressed under two intermittent illumination conditions: (1 hour on / 1 hour off) and (2 hours on / 2 hours off). In addition, when compared with the results of adhesion suppression effect confirmation test 1, it is presumed that hydrozoans have lower resistance to indigo light with a wavelength of 405±25 nm than barnacles.

[0105] [Adhesion suppression effect confirmation test 3] The effect of light irradiation on freshwater hydra was confirmed. 3 ml of test water was placed in a 12-well plate, and one freshwater hydra was placed in each well. After confirming that the tentacles and body were fully extended, LED light (peak wavelength: 405 nm) was irradiated from diagonally above the well plate under each of the irradiation conditions described below. The irradiation time was 3 minutes, and the freshwater hydra was observed under a microscope to see whether it contracted or shrunk its body during irradiation. 15 individuals were observed for each irradiation condition test.

[0106] The test water was prepared by adding 2 ml of each of the following solutions (a) to (c) to 1 L of pure water. (a) 0.5M CaCl2, 0.5M NaCl, 0.05M KCl (b) 0.05M MgSO4 (c) 0.5 M Tris HCl (pH 7.5)

[0107] The LED light irradiation conditions were irradiance of 500 Wm -2 Or 1000Wm -2 The intermittent illumination conditions were set as follows: the on time was fixed at 0.1 seconds, and the off time was set for each irradiance as follows: <500Wm -2 Lights out time in 0 seconds (i.e., continuous irradiation), 0.1 seconds, 0.2 seconds, 0.3 seconds, 0.4 seconds, 0.5 seconds, 0.6 seconds, 0.7 seconds, 0.8 seconds, 0.9 seconds, 1.0 seconds <1000Wm -2 Lights out time in 0 seconds (i.e., continuous irradiation), 0.8 seconds, 0.9 seconds, 1.0 seconds, 1.3 seconds, 1.5 seconds, 2.0 seconds, 3.0 seconds

[0108] (Test Results) Figure 13 shows the irradiance of 500 Wm -2 Figure 14 shows the evaluation of the reaction of freshwater hydra to the LED light irradiation under each intermittent irradiation condition in the case of irradiance or 1000Wm -2 The graphs show the evaluation of the reaction state of freshwater hydra to the irradiation of LED light under each intermittent irradiation condition in the case of 13. The horizontal axis of Fig. 13 and Fig. 14 shows the off time of each intermittent irradiation condition, and the vertical axis shows the percentage of freshwater hydra that showed each reaction among the total. The reaction state was evaluated as "body contraction" indicating that the body of the freshwater hydra contracted, "return after contraction" indicating that the body contracted and then returned to normal, and "no response" indicating that the freshwater hydra did not respond to the irradiation of the LED light. In Fig. 13 and Fig. 14, "body contraction" is shown by the densest dot pattern, "return after contraction" by the next densest dot pattern, and "no response" by the sparsest dot pattern.

[0109] As shown in Figure 13, the irradiance is 500 Wm -2 In the case of 1000Wm, it was confirmed that more than 80% of the individuals showed a body contraction reaction with a light-on time of 0.1 seconds and a light-off time of 0.1 to 0.3 seconds. -2 In the case of , it was confirmed that 80% or more of individuals showed a reaction of contracting their body when the light was on for 0.1 seconds and the light was off for 0.8 to 1.0 seconds. On the other hand, it was confirmed that the reaction rate of body contraction decreased when the light was off for 1.3 seconds or more. From these results, it is inferred that attachment to the target object can be suppressed for freshwater hydra by predetermined intermittent irradiation conditions set, for example, by the above formula (2), in the same way as continuous irradiation.

[0110] [Adhesion suppression effect confirmation test 4] The effect of light irradiation on bacterial growth was confirmed by smearing marine bacteria on an agar medium and counting the number of colonies that appeared after exposure to LED light.

[0111] 0.1 ml of seawater containing marine bacteria (all marine bacteria in seawater in barnacle breeding tanks) was dropped and smeared on the surface of the agar medium in a petri dish (diameter 9 cm x height 1.5 cm), and half of the smeared agar medium was covered with aluminum foil to serve as a control. LED light (peak wavelength: 405 nm) was then irradiated from above the petri dish under each irradiation condition shown in Table 8, and the number of colonies in the control and test areas on the surface of each agar medium was counted approximately 24 hours and approximately 48 hours after the start of irradiation. This was repeated three times, and the occurrence rate of colonies in the irradiated area relative to the number of colonies in the control area was calculated.

[0112] The agar medium was prepared by adding a powdered medium (Marine Agar 2216, Difco) to 1 L of distilled water, dissolving it by heating, sterilizing it, and then dispensing about 20 ml of the medium into a petri dish and leaving it to stand for 30 to 60 minutes to prepare a solid agar medium. The seawater used for smearing on the agar medium was diluted 10-fold with seawater filtered through a membrane with a pore size of 0.45 μm.

[0113] [Table 8]

[0114] (Test Results) Table 8 shows the irradiance of 200 Wm -2 When continuously irradiated for 8 hours at 400Wm -2 When the lamp is irradiated intermittently (1 minute on / 1 minute off) for 8 hours at an irradiance of 400 Wm -2 The figure shows the rate of colony appearance in the irradiated area compared to the control area when the light was turned on for 8 hours (1 hour on / 1 hour off). The LED light irradiation level under all three irradiation conditions was the same, at 1600 Whm -2 It is.

[0115] As shown in Table 8, the bacterial colony emergence rate was lower than 10% even after 48 hours under all irradiation conditions, and it was confirmed that intermittent irradiation had the same sterilization effect on marine bacteria as continuous irradiation. In addition, the bacterial colony emergence rate was almost the same under all irradiation conditions, and it was confirmed that the same amount of irradiation produces the same reproduction inhibition effect.

[0116] [Adhesion test 1] The test device was installed in the sea by hanging it with a metal chain or rope. The installation position was about 2m deep. The test device consisted of two test plates (made of polyvinyl chloride, 60cm x 60cm x 5mm thick, evaluation surface 50cm x 50cm) spaced apart, and an underwater LED lamp (peak wavelength: 407nm) that was placed between the two test plates and irradiated the two test plates with LED light was fixed to the frame. The distance between the irradiated surface of the underwater LED lamp and one of the test plates was about 20cm, and the distance between the irradiated surface of the underwater LED lamp and the other test plate was about 30cm. As a control, the test device was installed in the sea without an underwater LED lamp. The test period was about one month from April 14 to May 18, 2022. The test was conducted under the following six conditions.

[0117] Example 1: Underwater LED light (irradiance: 200Wm -2 (at the center of the evaluation surface of the test plate, distance from the test plate: 30 cm) was used, and intermittent irradiation was performed toward the center of the test plate by switching between irradiation and non-irradiation every second. Example 2: Underwater LED light (irradiance: 400Wm -2 (at the center of the evaluation surface of the test plate, distance from the test plate: 20 cm) was used, and intermittent irradiation was performed toward the center of the test plate by switching between irradiation and non-irradiation every second. Comparative example 1: Underwater LED light (irradiance: 200Wm -2 (at the center of the evaluation surface of the test plate, distance from the test plate: 30 cm) and continuous irradiation was performed toward the center of the test plate. Comparative example 2: Underwater LED light (irradiance: 400Wm -2(at the center of the evaluation surface of the test plate, distance from the test plate: 20 cm) was used, and continuous irradiation was performed toward the center of the test plate. Comparative Example 3: No underwater LED lights were used and the test surface was left in the sea (building side test surface). Comparative Example 4: No underwater LED lights were used and the device was left in the sea (test surface on the pier side).

[0118] (Test Results) Tables 9 and 10 show the state of organisms attached to the surface of the test plates in the control group. Table 9 shows the number of organisms attached to the surface of the test plates and the results of colony number analysis (coverage area for Ascidians and Scutellaria). Table 10 shows the results of wet weight analysis of organisms attached to the surface of the test plates (measured after each organism was peeled off).

[0119] [Table 9]

[0120] [Table 10]

[0121] In Comparative Examples 3 and 4, a large number of algae, colonial ascidians, amphipod mud tubes, bryozoans, etc. were found to be attached and covering the entire surface of the test plate. On the other hand, in both Comparative Examples 1 and 2 as well as in Examples 1 and 2, no attachment of organisms to the surface of the test plate, including the periphery, was observed at least with the naked eye. For this reason, -2 It was confirmed that even when the light was irradiated intermittently by switching on and off every second, it was possible to prevent the attachment of organisms.

[0122] [Adhesion test 2] The test device shown in FIG. 15 was installed by suspending it with a crane in the sea near the power plant intake. The installation position was adjusted to be 1 m below the lowest water level so that part of the test device would not be exposed above the sea even at low tide. As shown in FIG. 15, the test device was fixed to a frame 7, which included test plates P1 and P2 (made of polyvinyl chloride, 25 cm x 25 cm), as well as an underwater LED irradiation device (peak wavelength: 405 nm, manufactured by Delphys) that irradiates LED light onto test plate P2 as a test area. The distance between the irradiation surface of the underwater LED irradiation device and test plate P2 was approximately 35 cm. Test plate P1 was not irradiated with light and was used as a control area. The detection unit S of the water temperature sensor was placed in the center of test plates P1 and P2, respectively, and the change in water temperature was recorded by the recording unit M. The test period was approximately one month from August 19 to September 14, 2021. The following three types of LED devices were used as test areas.

[0123] Example 3: Small LED irradiation device (6-lamp type, irradiance setting: (at the position of the test plate surface) 100 Wm -2 ) was used, and irradiation was switched between on and off every 15 minutes using a lab timer to irradiate the center of the test panel P2 intermittently. Comparative Example 5: Small LED irradiation device (6-lamp type, irradiance setting: (at the position of the test plate surface) 100 Wm -2 ) was used to continuously irradiate the center of the test panel P2. Comparative Example 6: Large LED irradiation device (36-lamp type, irradiance setting: (at the position of the test plate surface) 100 Wm -2 ) was used to continuously irradiate the center of the test panel P2.

[0124] (Test Results) In the test plates P2 of Example 3 and Comparative Examples 5 and 6, it was confirmed that adhesion of foreign matter such as attached organisms was greatly suppressed near the center of the test plate P2 irradiated with LED light, compared with the control test plate P1. On the other hand, adhesion of green algae was confirmed around the center of the test plate P2 irradiated with LED light in Comparative Examples 5 and 6, and on the irradiated surface of the irradiation device. Almost no adhesion of the above-mentioned green algae was observed on the test plate P2 of Example 3.

[0125] FIG. 16 is an image of the foreign matter adhesion state of the test plate P2 of Comparative Example 6 after the adhesion test. Green algae A and fibrous green algae A1 were attached to the periphery of the central part of the test plate P2 of Comparative Example 6 where the LED light was irradiated. FIG. 17 is an image of the foreign matter adhesion state of the test plate P2 of Example 3 after the adhesion test. No green algae was found to be attached to the periphery of the central part of the test plate P2 of Example 3 where the LED light was irradiated. Therefore, it was confirmed that by intermittently irradiating the LED light of a predetermined wavelength, not only the adhesion of foreign matter such as attached organisms to the irradiated part of the LED light on the target object, but also the adhesion of green algae to the area around the irradiated part can be suppressed.

[0126] The water temperature change detected by the water temperature sensor was an increase of about 0.4°C compared to the control area in the small LED irradiation device used in Comparative Example 5, and an increase of about 0.6°C compared to the control area in the large LED irradiation device used in Comparative Example 6. On the other hand, in Example 3, it was confirmed that the water temperature quickly became equivalent to that of the control area when irradiation was switched to non-irradiation.

[0127] The small LED irradiation device after the adhesion test in Comparative Example 5 had an irradiance of 100 Wm -2 from 58.2Wm -2 The small LED irradiation device of Comparative Example 6 after the adhesion test had an irradiance of 100 Wm -2 from 22.5Wm -2 When the irradiation surfaces of the LED irradiation devices of Comparative Example 5 and Comparative Example 6 were cleaned and the irradiance was measured again, the irradiance was reduced to 100 Wm -2 It recovered to around 100%. Therefore, it is presumed that the decrease in irradiance in Comparative Example 5 and Comparative Example 6 is due to the adhesion of foreign matter to the irradiation surface. On the other hand, the small LED irradiation device of Example 3 did not show any decrease in irradiance after the adhesion test. Therefore, it was confirmed that the adhesion of foreign matter to the irradiation surface of the LED irradiation device can be suppressed by intermittently irradiating LED light of a specified wavelength.

[0128] [Test 1 to confirm the effect of light irradiation on airborne microorganisms] The microorganisms that had fallen onto LB medium were cultured and the number of colonies that appeared after exposure to LED light was counted to confirm the effect of light exposure on microorganisms attached to structures in the air.

[0129] 5g of tryptone, 2.5g of yeast extract, 5g of NaCl, 7.5g of agar, and 480ml of distilled water were added to a medium bottle and stirred, then autoclaved at 121°C for 20 minutes, and 20ml of the mixture was dispensed into a petri dish and solidified at room temperature to prepare LB medium. The three petri dishes containing this LB medium were placed on a counter about 90cm above the floor near the exit to the outdoors with the lids open, and left to stand for 8 hours. After 8 hours, the lids were closed, and the three petri dishes were designated as samples 1 to 3, and LED light (peak wavelength: 405nm) was irradiated from directly above each sample under the irradiation conditions for each sample shown in Table 11. After 8 hours from the start of irradiation, each sample was cultured for 48 hours in a constant temperature incubator set at 35°C, and the number of colonies on the medium surface of each sample was counted. UFL-501-08 UV-UT (manufactured by U-Technology Co., Ltd.) was used as the light source of the LED light. Sample 3, which was a petri dish that was left unexposed for 8 hours without being irradiated with LED light, was used as a control.

[0130] [Table 11]

[0131] (Test Results) Table 11 shows the number of colonies for each sample and the irradiation dose of 1600Whm -2 The figures show the sterilization rates for the control area when LED light was irradiated continuously and intermittently. The sterilization rate for the control area shown in Table 11 is the value obtained by dividing the number of colonies in sample 1 or 2 after irradiation with LED light by the number of colonies in the control area of ​​sample 3. As shown in Table 11, 47 bacterial and fungal colonies were observed in sample 3, which is the control area. In contrast, one colony was observed in sample 1 and three colonies were observed in sample 2, and the sterilization rate was 100% when the irradiance Y in formula (1) above was 200 Wm -2By irradiating the LED light with intermittent irradiation, the sterilization rate was over 90%. This result shows that a irradiance Y of 200 Wm2 is also effective against airborne bacteria and fungi that adhere to the surfaces of airborne structures. -2 It is presumed that by adjusting the concentration as described above, it is possible to almost completely suppress the attachment and / or proliferation of sessile organisms that attach to structures in the air.

[0132] [Test 2 to confirm the effect of light irradiation on airborne microorganisms] The microorganisms that had fallen onto the LB medium were cultivated, and the number of colonies that appeared after exposure to LED light at a lower irradiance than the radiation conditions shown in Table 12 was counted to confirm the effect of light exposure on the microorganisms attached to structures in the air.

[0133] LB medium was prepared using the same procedure as in "Test 1 for Confirming the Effect of Light Irradiation on Microorganisms in the Air," and the LB medium was placed on a counter about 90 cm above the floor near the exit to the outdoors with the lids open, and left to stand for 8 hours. After 8 hours, the lids were closed, and the five dishes were designated as samples 4 to 8, and LED light (peak wavelength: 405 nm) was irradiated from directly above each sample under the irradiation conditions for each sample shown in Table 14. After 8 hours from the start of irradiation, each sample was cultured for 48 hours in a constant temperature incubator set at 35°C, and the number of colonies on the medium surface of each sample was counted. UFL-501-08 UV-UT (manufactured by U-Technology Co., Ltd.) was used as the light source for the LED light. Samples 6 to 8, which were dishes that were left to stand for 8 hours without being irradiated with LED light, were used as controls.

[0134] [Table 12]

[0135] (Test Results) Table 12 shows the number of colonies for each sample and the irradiation dose of 160Whm -2The figures show the sterilization rates relative to the average colony count in the control area when LED light was continuously irradiated and when it was intermittently irradiated. The sterilization rates relative to the average colony count in the control area shown in Table 12 are calculated by dividing the number of colonies in sample 4 or 5 after irradiation with LED light by the average number of colonies in the control areas of samples 6 to 8. As shown in Table 12, 13 to 18 bacterial and fungal colonies were observed in the three control areas. In contrast, five colonies were observed each in samples 4 and 5, and the sterilization rates were approximately 10% when the irradiance Y in formula (1) above was 20 Wm -2 The sterilization rate was 60% or more even when the LED light was irradiated with intermittent irradiation of 1000 W / m. This result shows that the irradiance Y of 20 W / m is sufficient for airborne bacteria, fungi, and other attached organisms that adhere to the surfaces of airborne structures. -2 It is presumed that by adjusting the amount as described above, the attachment and proliferation of sessile organisms on the target object can be efficiently suppressed. [Explanation of symbols]

[0136] 1, 1a, 1b, 1c water quality meter 10. Attachment and propagation suppression device 20, 20a, 20b, 20c, 20d, 20e irradiation equipment 22a, 22b, 22c, 22d, 22e irradiation surface 31, 32, 33, 34, 35, 36, 37, 38 Detector 5, 5a, 5b, 5c control section

Claims

1. A method for inhibiting adhesion and / or proliferation of sessile organisms on an object to which the sessile organisms may adhere, comprising: A method for inhibiting adhesion and propagation of bacteria, comprising intermittently irradiating the object with light, the method comprising: satisfying the condition represented by the following formula (1): X×a / (a+b)≧Y...Formula (1) where X is the irradiance of light (Wm －２ ), a is the time when light is irradiated, b is the time when light is not irradiated, and Y is the irradiance of light (Wm －２ ).

2. 2. The method for inhibiting adhesion propagation according to claim 1, wherein Y in formula (1) is 20.

3. 2. The method for inhibiting adhesion propagation according to claim 1, wherein Y in formula (1) is 150.

4. The method for inhibiting adhesion and propagation of microorganisms according to any one of claims 1 to 3, wherein the light irradiated to the object has a peak in a wavelength range of 400 to 430 nm.

5. An adhesion and proliferation inhibition device having an irradiation device that irradiates light onto an object to which adhesion organisms are attached, and a control unit that controls the irradiation device, The control unit controls the irradiation device so that light is irradiated from the irradiation device to the object intermittently while satisfying the condition expressed by the following formula (1). X×a / (a+b)≧Y...Formula (1) where X is the irradiance of the light from the irradiation device (Wm －２ ), a is the time when light is irradiated from the irradiation device, b is the time when light is not irradiated from the irradiation device, and Y is the irradiance of light (Wm －２ ).

6. A water quality meter comprising the adhesion propagation inhibition device according to claim 4 and a sensor device, the illumination device illuminates a detection unit of the sensor device with light; the light irradiated from the irradiation device has a peak in a wavelength range of 400 to 430 nm; The sensor device performs a detection operation at each predetermined detection timing, The control unit controls the irradiation device so that light is intermittently irradiated from the irradiation device to the detection unit for each irradiation time other than the specified detection timing.

7. The water quality meter according to claim 6 , wherein an irradiation surface of the irradiation device is disposed opposite to the detection unit.

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