JPS63162089A - Method for preventing sticking of marine organism by using external ultraviolet light source - Google Patents

Abstract

PURPOSE:To assure high safety and excellent maintenance characteristic, by sending the UV rays condensed from an external UV light source into one end of an optical fiber cable, putting the cable into sea water, and projecting the UV rays in the sea water from the other end of the cable. CONSTITUTION:The UV light is projected to the systems of a heat exchanger which uses the sea water as its cooling water or a marine structure or ship which is in constant contact with the sea water in order to prevent the propagation of adhesive contaminating organism. The UV rays condensed from the external UV light source 2 is sent into one end of the optical fiber cable 7 without immersing a UV lamp directly into the sea water. This cable 7 is put into the sea water and the UV rays are projected in the sea water from the other end of the cable. As a result, the safety is enhanced and the maintenance characteristic is improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for preventing the adhesion of marine organisms, particularly in a seawater cooling water system for a tubular heat exchanger such as a condenser used in a turbine, etc. This invention relates to improvements in methods for preventing marine organisms from growing on structures such as condenser ice chambers, pipes, and system strainers.

[Conventional technology]

The growth of marine organisms in the cooling seawater system may cause blockage or abnormal damage to the condenser tubules due to deposits or their falling off and flowing, and may cause abnormalities in the strainer or other structures within the system. This can lead to blockages and a decrease in water supply, which can cause problems in plant operation. Conventionally, chlorine injection has been used as a method to prevent the growth of marine organisms. As is well known, chlorine has a high sterilizing power against marine organisms, and as described in Japanese Patent Publication No. 52-335&2, it electrolyzes seawater and generates hypochlorous acid from chlorine ions in seawater to prevent marine organisms from adhering to it. A method is used to do this.

However, when chlorine is injected into large amounts of cooling seawater used in power generation plants, etc., the method of chlorine injection is avoided from the perspective of environmental conservation, as the wastewater seawater may have a negative impact on the marine ecosystem. There is a tendency.

For this reason, there is a method of irradiating ultraviolet light that does not affect the environment and has a high adhesion prevention effect.

This method utilizes the sterilizing effect of ultraviolet light with a wavelength of 253.7 nm, and irradiates ultraviolet light onto environmental areas where marine organisms are likely to attach and grow, making the irradiated area an unsuitable environment for marine organisms to live in. It is.

The simplest way to irradiate ultraviolet rays is with a dominant wavelength of 253.
．． There is a method of waterproofing a 7 nm ultraviolet lamp with a quartz outer tube and submerging it in water.

[Problems to be solved by the invention] However, according to this method, the lamp itself is submerged in water, so
It has the following drawbacks.

First, the amount of cooling seawater used in a power generation plant is extremely large, and not only does it have a large impact force on the lamps, but the pressure may also be high. Ultraviolet rays are severely attenuated by materials other than quartz glass, and quartz glass must be used as a protective cover, which limits its strength. In the event that a solid foreign object enters the first water and collides with the quartz glass surface,
This can be damaged and the lamp may no longer function.

Second, if the lamp stops functioning due to end of life or abnormality during operation, the cooling seawater system must be temporarily stopped in order to check or replace the lamp. In power generation plants, it may not be possible to shut down the cooling seawater system for several weeks due to power generation issues and other issues. Therefore, during this time, there is a risk that attached growth of marine organisms will occur.

An object of the present invention is to provide an ultraviolet irradiation method that is highly safe and easy to maintain.

[Means for solving problems]

The above purpose is to place an external UV light source outside the cooling seawater system, without directly submerging the UV lamp in water, and to collect the UV light efficiently using a reflector whose inner surface has been treated with aluminum vapor deposition to reflect the UV light. This is accomplished by pumping ultraviolet light into one end of a highly transparent quartz fiber and placing the other end of the fiber in seawater.

[Effect]

That is, since only the end of the fiber is flooded,
It can easily withstand the severe usage conditions mentioned above, and is also less likely to be damaged by solid foreign matter. Furthermore, since the lamp body is in the air, even if the fiber is damaged, the lamp function will be maintained, and the lamp can be replaced regardless of the seawater system.

Furthermore, by increasing the number of fibers and arranging their exit ends in various directions, the rotating acid can be placed at the opening of the reflector by installing a moving reflector in front of the fiber inlet end of the external light source. It is possible to send out concentrated ultraviolet rays from the fiber entrance and irradiate high-intensity ultraviolet rays in any direction. Further, by adjusting the shape of the opening of the reflecting plate and the speed at which the rotating acid moves, it becomes possible to arbitrarily adjust the ultraviolet irradiance and irradiation time.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. FIG. 1 shows an overall view of an ultraviolet irradiation device using an external ultraviolet light source according to the present invention attached to an area to be prevented from adhering to marine organisms.

B Gold part 1. UV lamp 2. Large reflector 3 and small reflector 4
The light source housing 5 is fixed to the protective housing 8 of the fiber cable 7 with a presser 6. An irradiation section 9 that collects the outlet ends of the fiber cables 7 is attached to the tip of the maintenance body 8. ? ! It is installed and fixed together with the housing 8 in seawater by the fixing part 10.

A small drive device is built inside the light source housing 5 and rotates the shaft 11. FIG. 2 shows the end of the fiber cable 7 of the protective housing 8 on the light source side, and a large number of fiber ends are arranged radially. A reflecting plate 12 that rotates while being connected to the shaft 11 is attached in contact with this surface. This reflecting plate 12 has two elongated openings 13 as shown in FIG. The stopper 14 is a rod for fixing the small reflecting mirror 4.

FIG. 3 shows the irradiation side end of the fiber cable 7 of the irradiation section 9, which is arranged in a grid pattern on the semi-cylindrical outer surface. The fiber cable 7 is routed in the protective housing 8 so that the fiber cable 7 in the opening 13 shown in FIG. ing.

When electricity is applied to the base part 1 and the UV lamp 2 is turned on, ultraviolet light with a main wavelength of 253.7 nm is generated, which has a large reflection @3
The small reflector 4 directs the fiber cable 7 toward the inlet end. Since there is a reflector plate 12 at this inlet end, fibers other than the ends of the rows located in the openings 13 are also reflected. In this way, concentrated ultraviolet light enters the opening 13.

This ultraviolet light is irradiated from a certain row of fiber ends in the axial direction of the semicircular cylinder of the irradiation section 9. Therefore, by rotating the first reflecting plate 12, it appears that the plane light is irradiated from the irradiating section 9 while moving 180'.

According to this embodiment, the rotational movement of the reflection plate 12 and the opening 1
By changing the shape of 3, various irradiation amounts, irradiation times, and irradiation patterns can be obtained for the direction of the fiber end arranged in the irradiation section 9, so that effective irradiation can be performed for the installation environment. There is an effect. In addition, since the irradiation unit 9 is already sealed with seawater, inspection or replacement of the ultraviolet lamp 2 can be carried out at any time by removing the presser 6, regardless of the seawater system. be.

〔Effect of the invention〕

According to the present invention, ml of seawater in the irradiated area! It is possible to create a structure that is less susceptible to damage due to environmental conditions such as pressure and collision with solid foreign objects, and even if damage occurs, it will not directly affect the UV lamp, making it possible to perform highly safe irradiation. There is an effect that it can be done.

Furthermore, since the ultraviolet lamp can be operated independently of the seawater system, the irradiation device has the advantage of being easy to maintain.

Furthermore, various irradiation patterns can be obtained depending on the shape of the opening, how it is moved, and how the inlet and outlet ends of the fiber cable are arranged, so there is flexibility for highly efficient irradiation.

[Brief explanation of the drawing]

FIG. 1 is an overall view showing one embodiment of the present invention, FIG. 2 is a sectional view taken along the line ■--■ in FIG. 1, and FIG. 3 is a view taken along the line mm in FIG. 1. 1... Base portion, 2... Ultraviolet lamp, 3... Large reflecting mirror, 4... Small reflecting mirror, 5... Light source housing, 6...
Holding tool, 7... Fiber cable, 8... Protective casing, 9... Irradiation section, 10... Fixing section, 11... Shaft, 12... Reflection plate. 13... opening, 14... stopper.

Claims (1)

[Claims] 1. To prevent the growth of adherent fouling organisms on systems such as heat exchangers that use seawater as cooling water or on marine structures and ships that are in constant contact with seawater. In the method of irradiating ultraviolet light, the ultraviolet lamp is not directly immersed in seawater, but instead the ultraviolet light is concentrated from an external ultraviolet light source and sent to one end of an optical fiber cable, the cable is placed in seawater, and the other end is A method for preventing the adhesion of marine organisms, which is characterized by irradiating ultraviolet rays into seawater from the end of a cable. 2. In an external ultraviolet light source consisting of an ultraviolet lamp and multiple optical fiber cable ends, a reflector plate with a rotating or moving aperture is installed in front of the group of fiber ends so that concentrated ultraviolet light hits the aperture. The marine habitat according to claim 1, wherein the direction and intensity of ultraviolet irradiation are variable by configuring a reflecting mirror and arbitrarily combining the shape and movement method of the aperture and the arrangement of the irradiation end of the fiber. Biofouling prevention method.