JPH0764690B2 - Method of manufacturing biofouling prevention tube - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antifouling structure having a function of preventing the adhesion of marine organisms such as barnacles, purple shellfish and algae.

[0002]

2. Description of the Related Art Marine structures in contact with seawater are constantly exposed to fouling due to the adhesion of marine life. Therefore, not only the appearance of the ordinary marine structure is impaired but also the functional structure is impaired. For example, in the case of a ship, the resistance increases due to the adhesion of sea life to the bottom surface of the hull and the like, and the propulsion speed of the hull decreases. Further, in the case of a thermal power plant, if marine organisms adhere to the seawater intake pit, the flow of seawater, which is a cooling medium, may be impaired, and power generation may have to be stopped.

For this reason, many techniques for preventing adhesion of marine organisms have been studied in the past. Among them, one of the techniques for preventing adhesion of marine organisms, which is currently in practical use, is a paint containing cuprous oxide or organotin. It is a method of applying to the contact surface of the marine structure with seawater. Further, JP-A-60-209505 discloses a biofouling-preventing pressure-sensitive adhesive body in which a primer layer is provided on one surface of a plate made of copper or a copper alloy, and a pressure-sensitive adhesive layer is formed on the primer layer.

[0004]

However, according to such a conventional antifouling method using a paint, even if the paint is applied thickly, the paint is easily peeled off, so that the life expectancy of a remarkable antifouling effect is It takes about one year, and complicated maintenance work is required to reapply it every year. In addition, JP-A-60-20
The marine organism adhesion preventive body disclosed in Japanese Patent Publication No. 9505 is copper or a copper-nickel (Cu-Ni) alloy, and its corrosion resistance and antifouling performance are insufficient.

According to many years of experimental research conducted by the present inventor, it has been found that when a beryllium copper alloy is used in a marine structure, an extremely excellent antifouling effect can be obtained. this is,
It is presumed that beryllium ion acts synergistically with copper ion, exerts a great repellent effect on marine life, and prevents the reproduction of marine life. It has been found by the present inventor that the beryllium copper alloy has an effect of exhibiting an antifouling function and a continuous action of elution of copper ions.

The object of the present invention is to prevent the adhesion of marine organisms,
An object of the present invention is to provide a simple manufacturing method of a tubular body which has excellent durability, requires no maintenance, and is non-toxic.

[0007]

A method for manufacturing a biofouling prevention tube according to the present invention for solving the above-mentioned problems is a method in which a thin plate of beryllium copper alloy is spirally wound around the outer periphery of a core rod, and the outer periphery of this thin plate is electrically charged. It is characterized in that an insulating resin is formed and then the core rod is pulled out. The beryllium copper alloy has a beryllium content of 0.2 to 2.8% by weight, and Be-
Cu alloy, Be-Co-Cu alloy, Be-Co-Si-
It is characterized in that it is any one selected from the group consisting of a Cu alloy and a Be-Ni-Cu alloy. The composition of the beryllium copper alloy is, for example, Be: 0.2 to 1.
0% by weight, Co: 2.4 to 2.7% by weight, balance Cu and unavoidable impurities, Be: 0.2 to 1.0% by weight, N
i: 1.4 to 2.2 wt%, balance Cu and unavoidable impurities, Be: 1.0 to 2.0 wt%, Co: 0.2 to
0.6% by weight, balance Cu and inevitable impurities, Be:
1.6-2.8% by weight, Co: 0.4-1.0% by weight,
Si: 0.2 to 0.35% by weight, balance Cu and inevitable impurities.

[0008]

The method for producing a biofouling prevention tube according to the present invention uses a core rod, spirally wraps a thin plate of beryllium copper alloy around the outer periphery of the core rod, and forms an electrically insulating resin on the outer periphery of the thin plate. Then, since the core rod is removed, the beryllium copper alloy thin plate can be lined on the inner peripheral wall, which is difficult to form, by a simple means.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1st of this invention regarding the manufacturing method of the pipe which flows seawater
An example is shown in FIG. As shown in FIG. 1 (A), the core rod 1
A thin plate 2 of beryllium copper alloy is spirally wound around. As shown in FIG. 1B, the outer shell is covered with an electrically insulating resin 3 and adhered to the thin plate 2. Then, the core rod 1 is pulled out. As shown in FIG. 1C, the obtained tubular body 7 has a thin plate 2 of beryllium copper alloy formed on the inner peripheral wall surface.

This beryllium-copper alloy has an effect of exhibiting an antifouling function and a continuous action of elution of copper ions. The effect of exhibiting the antifouling function and the sustained action of elution of copper ions are described in detail below. Effect of antifouling function The ionization tendency of beryllium, copper and nickel is Be> N
It is known from the literature that i> Cu, indicating that the element on the left is more likely to elute. In the case of beryllium copper, beryllium elutes first to form a local battery to exert a biofouling prevention effect due to the current effect, and the beryllium ion takes an oxidized form called internal oxidation. This internal oxidation forms a BeO film on the inside.
The porosity of the coating allows the elution of copper to form Cu ₂ O + BeO on the surface. It is considered that the antifouling function is exhibited by the elution of this copper ion into seawater.

Sustaining action of copper ion elution The above-described effect of exhibiting the antifouling function has a continuing action of eluting copper ions. That is, beryllium copper has an action of continuing the antifouling function without stopping. Beryllium copper that comes into contact with seawater has a dense surface oxide (Cu ₂ O) formed on its surface.
A film of eO inner oxide is formed. Therefore, the elution of copper into seawater is maintained, and the volume of this film increases due to oxidation. When the volume increase of the film reaches a certain amount, the oxide film on the surface is separated from the porous internal oxide layer. Therefore, it is considered that the electrochemical action and the elution of copper are maintained for a long time.

Further, the continuous action of copper ion elution generated by beryllium copper will be explained as follows using the schematic diagram shown in FIG. 4 when comparing beryllium copper and cupro-nickel. As shown in FIG. 4, when beryllium copper (BeCu) has a certain thickness of a corrosion product (oxide), the corrosion product is peeled off. Then, the surface of the beryllium copper alloy appears, and the thickness of the corrosion product increases as the corrosion progresses again. Then, the corrosion product is peeled off again when it reaches a certain thickness, which is repeated. On the other hand, the elution of ions decreases as the thickness of the corrosion product increases, which gradually decreases. However, when the corrosion products are peeled off as described above, the surface of the alloy appears and the amount of ion elution increases. Therefore, the increase and decrease of copper ion elution are repeated.

In the beryllium copper of the embodiment of the present invention, the stripping of the oxide film has the effect of sustaining the elution of copper ions. As a result, the amount of marine organisms adhering to the surface of copper beryllium is small or hardly adhered. On the other hand, in the case of Cupro nickel (CuNi) of the comparative example,
Dense nickel oxide N on the surface layer due to some aging
Formation of iO ₂ or copper oxide Cu ₂ O results in the formation of FIG.
As shown in, the elution of copper ions is suppressed. this is,
According to the ionization tendency (Be>Ni> Cu), it is considered that in the case of cupro nickel, nickel (Ni) is preferentially eluted to form a local battery, which is because a dense oxide is formed on the surface. Therefore, in the case of cupronickel, the thickness of the corrosion product initially increases with time, but the growth rate of the corrosion product gradually decreases. At the same time, the elution amount of copper ions gradually decreases. Moreover, with Cupro nickel, flaking of corrosion products does not occur as easily as with copper beryllium. Therefore, the elution amount of ions remains at a low level, and the antifouling effect decreases.

The present inventors have for the first time discovered that the beryllium copper alloy has such a remarkable effect of the antifouling function and a lasting action of elution of copper ions. The present inventor is unaware of any prior art document that refers to or points out. As a practical beryllium copper alloy, 11 alloys having a beryllium content of 0.2 to 0.6% by weight and a beryllium content of 1.8 to 2.0% by weight.
Various alloys such as No. 25 alloy are specified by JIS, but those having a beryllium content of 1.6% or more are preferable in terms of antifouling effect. When the content of beryllium exceeds 2.8%, beryllium does not form a solid solution in copper any more, so that the antifouling effect is excellent but the wrought workability is gradually reduced.

Next, FIG. 2 shows a second embodiment in which a thin plate of beryllium copper alloy of the present invention is wound around a core rod. The second embodiment is
This is an example in which the thin plate 2 is wound so that a gap 5 is formed when the thin plate 2 of beryllium copper alloy is spirally wound around the core rod 1. In this state, it is inserted into the resin tube body, and then the core rod is pulled out. In the obtained tube, a beryllium-copper alloy is partially formed on the inner wall surface of the tube, and the resin is exposed at other parts.

Also in this second embodiment, the adhesion and reproduction of marine organisms can be prevented by the antifouling effect of the beryllium copper alloy and its sustaining effect. FIG. 3 shows a third embodiment of a method of winding a thin plate of beryllium copper alloy of the present invention. In the third embodiment, a thin plate 2 of beryllium copper alloy is provided with a gap 5 on the outer periphery of a core rod 1.
This is an example in which a beryllium copper alloy thin plate 2 is wound so as to be wound in a spiral shape so that the gap 5 can be covered.
The outer shell of this is coated with resin. Then, pull out the core rod 1. The inner wall of the obtained tube is entirely formed of beryllium copper alloy.

[0017]

As described above, according to the method for producing an organism adhesion preventing pipe of the present invention, a marine organism adhesion preventing pipe can be produced by a relatively simple operation. Further, according to the antifouling structure attached by this method, there are effects that it is excellent in corrosion resistance, maintenance work is simple, there is no problem of toxicity, and the adhesion of marine life is effectively prevented.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a method of manufacturing a biofouling prevention tube according to a first embodiment of the present invention.

FIG. 2 is an explanatory view showing a method for winding a beryllium copper alloy thin plate according to a second embodiment of the present invention.

FIG. 3 is an explanatory view showing a method for winding a beryllium copper alloy thin plate according to a third embodiment of the present invention.

FIG. 4 is a schematic explanatory diagram comparing changes over time in the amount of copper ions eluted and the thickness of corrosion products for beryllium copper and cupro nickel.

[Explanation of symbols]

 1 core rod 2 beryllium copper alloy thin plate 3 resin

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Claims (2)

[Claims] 1. A biofouling prevention device, characterized in that a thin plate of beryllium copper alloy is spirally wound around the outer periphery of a core rod, an electrically insulating resin is formed on the outer periphery of the thin plate, and then the core rod is pulled out. Pipe manufacturing method. 2. The beryllium copper alloy has a beryllium content of 0.2 to 2.8% by weight, and a Be--Cu alloy,
2. The biofouling prevention tube according to claim 1, wherein the biofouling prevention tube is selected from the group consisting of Be-Co-Cu alloy, Be-Co-Si-Cu alloy and Be-Ni-Cu alloy. Method.