JPH07310999A - Fresh-water film type antifouling device - Google Patents

Abstract

PURPOSE:To prevent marine life from sticking to and growing on the inside of a piping transferring seawater. CONSTITUTION:A fresh-water film antifouling device 3 is provided for a circulation water pipe 2. A plurality of outflow ports 4 in the shape of slits in the circumferential direction are provided in the circulation water pipe 2, with appropriate intervals maintained in the longitudinal direction, and river water supplied from a fresh-water supply piping 5 is made to flow out into the circulation water pipe 2 from the outflow ports 4 of fresh water so that a fresh-water film 6 be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fresh water film type antifouling device for preventing marine organisms from adhering to and growing on the inner surface of a pipe for transferring seawater.

[0002]

2. Description of the Related Art A condenser used in a thermal power plant or a nuclear power plant is connected to an exhaust port of a steam turbine and cools steam discharged from the steam turbine with cooling water to condense it.
By setting the back pressure of the steam turbine to be a vacuum, the pressure difference between the steam inlet and the exhaust port of the steam turbine is increased to extract more energy from the steam turbine.

Seawater is often used as the cooling water, but in the piping from the sea to the condenser and the piping from the condenser to the sea, marine organisms such as shellfish and algae adhere to the inner wall surface. However, it grows there and the wall surface becomes uneven, which causes an increase in flow resistance in the pipe. Also, when marine organisms grow on the wall surface, a thick layer is formed and this layer peels off at once and flows to the condenser, blocking the heat transfer tube of the condenser and reducing the performance of the condenser, This causes problems such as leaking seawater from the heat transfer tubes and forcing the power plant to shut down.

In order to avoid such problems, conventionally, an antifouling paint to which marine organisms are unlikely to adhere has been applied to the inner wall surface such as a pipe which is in contact with seawater to suppress the adhesion of marine organisms. It cannot be prevented, and the plant is regularly shut down to remove marine organisms adhering to the wall surface.

[0005]

However, shutting down the power plant to remove marine organisms must be avoided during the summer when the demand for electricity increases. Also, in regions where the seawater temperature is high, it is necessary to carry out every week, but it is required to reduce the number of times as much as possible to suppress the decrease in electrical output.

On the other hand, since this antifouling paint deteriorates with age and marine organisms tend to adhere to it, it is necessary to periodically remove the paint and reapply the antifouling paint. In addition to this countermeasure, there was a temporary method of killing marine organisms by introducing a chemical solution into seawater, but another problem of marine pollution occurred and it is not currently implemented. An object of the present invention is to provide a fresh water film type antifouling device which does not require periodic cleaning of the inner wall surface of a pipe and does not cause the problem of marine pollution.

[0007]

According to the present invention, a through hole is provided in a wall surface of a pipe for transferring seawater, fresh water such as river water is allowed to flow out from the outside through the through hole, and marine organisms adhere to the inner surface of the pipe. It is characterized in that it is adapted to prevent growth.

[0008]

[Function] When fresh water gradually flows out from the wall surface of the pipe that is in contact with seawater, the freshwater flowing out from the wall flows along the wall surface and forms a freshwater film with a low concentration of seawater in a certain section downstream from the through hole. And do not mix immediately.

Therefore, the eggs and larvae of the marine organisms are blocked by the fresh water film formed on the wall surface of the pipe, and do not come close to the wall surface, and are unlikely to adhere. In addition, since it is difficult for marine organisms to approach the wall surface, it is difficult to lay eggs on the wall surface.

Even if marine organisms lay eggs on the wall surface of the pipe that is in contact with seawater, or even if eggs and larvae of marine organisms flow and adhere, the place near the wall surface is only fresh water or fresh water and seawater are replaced. Because it is a place, marine life will die.

The fact that marine organisms die in a place where only fresh water or where fresh water and seawater are exchanged means that marine organisms are rarely inhabited in the vicinity of the estuary and that piping for passing seawater that is rarely used is used. While not in use, it is clear that fresh water is stored in the pipe to prevent the growth of marine organisms and to be effective.

Thus, the eggs and larvae attached to the wall surface of the pipe do not grow and die. Here, it is clear that freshwater kills marine organisms, but since rainwater and river water originally flow into the ocean as a natural phenomenon, they do not cause marine pollution at all.

[0013]

EXAMPLE FIG. 2 shows the overall construction of this example. Further, FIG. 1 shows the details of the fresh water film type antifouling device according to the present embodiment. In this embodiment, a fresh water film antifouling device 3 according to the present invention is provided on a circulating water pipe 2 of a thermal power and nuclear power plant.
A plurality of circumferential slit-shaped outflow holes 4 are provided at appropriate intervals in the longitudinal direction, and the river water supplied from the freshwater supply pipe 5 is allowed to flow out from the outflow holes 4 into the circulating water pipe 2 to form a freshwater film. 6 is formed.

The installation intervals of the outflow holes 4 take into consideration that the fresh water 8 flowing out from the outflow holes 4 mixes with the seawater 7 and does not return to a seawater concentration where marine organisms can live on the wall surface. When the fresh water 8 gradually flows out from the wall surface of the circulating water pipe 2 that is in contact with the sea water 7, the fresh water 8 flowing out from the wall surface flows along the wall surface, and the fresh water film 6 with a low concentration of sea water flows in a certain section downstream from the outflow hole 4.
The fresh water 8 does not mix immediately with the sea water 7.

Therefore, the eggs and larvae of marine organisms are circulated water pipe 2
Is blocked by the fresh water film 6 formed on the wall surface and does not come close to the wall surface and becomes difficult to adhere. In addition, since it is difficult for marine organisms to approach the wall surface, it is difficult to lay eggs on the wall surface.

Even if marine organisms lay eggs on the wall of the circulating water pipe 2 in contact with the seawater 7, or even if eggs and larvae of the marine organisms flow and adhere, the freshwater 8 is the only place near the wall or freshwater. 8 and 7 are replaced by each other, so marine life will die.

The shape of the outflow hole 6 may be configured as in the embodiment described later, but it goes without saying that other shapes can be adopted. Further, in the circulating water pipe 2 of the condenser 1, hot water such as high-temperature drainage discharged in the plant is discharged from the wall surface to form a hot water film along the wall surface, thereby killing marine organisms. .

Another embodiment of the present invention will be described with reference to FIG. In this embodiment, the slit-shaped outflow hole 4 of the above embodiment is used.
Instead of the above, a porous outflow hole 9 is provided. Also in this embodiment, the same effect as that of the above embodiment can be obtained.

[0019]

As described above, since the antifouling device according to the present invention uses fresh water, there is no problem of marine pollution, and the fresh water can be discharged from the inner surface of the pipe to prevent marine pollution. Since it is possible to prevent organisms from adhering and growing, it is possible to prevent the flow resistance in the pipe from increasing due to unevenness on the inner wall of the pipe due to the growth of marine organisms. In addition, marine organisms that grew in a thick layer on the wall separated and flowed to the condenser,
Blocking the heat transfer tube of the condenser, reducing the performance of the condenser,
It is possible to solve the problem that seawater leaks from the heat transfer tube and the plant must be stopped.

[Brief description of drawings]

FIG. 1 is a sectional view showing a fresh water film type antifouling device according to the present invention.

FIG. 2 is an overall configuration diagram showing a mounted state of the antifouling device shown in FIG.

FIG. 3 is a sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 1 Condenser 2 Circulating water pipe 3 Freshwater film type antifouling device 4,9 Outflow hole 5 Freshwater supply pipe 6 Freshwater film 7 Seawater 8 Freshwater

Claims (3)

[Claims] 1. A through hole is provided in a wall surface of a pipe for transferring seawater, and fresh water such as river water is allowed to flow from the outside through the through hole to prevent marine organisms from adhering to and growing on the inner surface of the pipe. A fresh water film-type antifouling device characterized in that 2. The fresh water film type antifouling device according to claim 1, wherein the pipe is a circulating water pipe connected to a condenser of a power plant. 3. The fresh water film type antifouling device according to claim 2, wherein hot water is allowed to flow out from a wall surface of the circulating water pipe from a condenser outlet to the ocean.