JPH04278038A - Net for crawl - Google Patents

Abstract

PURPOSE:To provide a crawl net having rich abrasion resistance and rich corrosion resistance against sea water. CONSTITUTION:The cables of a nickel.titanium alloy are knitted to form a crawl net. The crawl net has sufficient abrasion resistance, corrosion resistance against sea water and strength, is profitable and permits to extremely reduce the frequency of the generation of troubles such as the escape of culturing fishes due to the breakage of the net used.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to fish cage nets that are highly resistant to abrasion and corrosion against seawater.

0002

[Prior art] As a means of cultivating sea fish in inland seas and open oceans,
Generally, cage nets are used. In this method, a net is stretched in a circle in the sea to create a cage, and the fish to be cultured are raised in this cage in a migratory state. The degree of mesh in this fish cage net varies depending on the size of the fish to be cultured, etc., but the wire used to make the net may be made of synthetic resin rope such as nylon or galvanized copper wire. ing. Stainless steel nets are also widely used for shrimp farming.

0003

[Problems to be Solved by the Invention] Fish cage nets are used for long periods of time while immersed in seawater, and especially when installed in the open ocean, they are constantly exposed to rough waves. Furthermore, each time a fish is landed from a fish cage net, it is necessary to fold the net and pull it onto land, and therefore, a large external stress is applied to the fish cage net during use. For this reason, fish cage nets made of nylon ropes have a durability of only about two to three years, and often break in various places. Furthermore, even fish cage nets that use metal wire rods are not necessarily more durable than nets made of nylon material, and in addition, they have other drawbacks. For example, if stainless steel wire is used for fish cage nets, durability will be significantly reduced due to rusting. The reason for this is that stainless steel generally has an oxide film that prevents rust from progressing, but when it is used as a material for fish cage nets, the materials constantly rub against each other and the oxide film peels off, which prevents rust from forming. This is because it progresses rapidly. Particularly in the case of fish cage nets, if even one part of the net breaks due to deterioration of durability, the farmed fish will escape from that part. This is an important concern for net manufacturers, as it can cause great damage to aquaculture farmers and lead to compensation issues.

[0004] Furthermore, when galvanized copper wire is used in fish cage nets, the zinc component elutes into the seawater, contaminating the ocean and farmed fish, and having a negative impact on the marine product ecosystem. This is actually happening. In this respect, nylon nets do not cause the above-mentioned problems, but they do have the disadvantage that a large amount of shellfish such as barnacles and seaweed adhere to them during long-term use, causing clogging. When the fish cage net becomes clogged in this way, the circulation of seawater inside and outside the fish cage is blocked, which has a negative impact on the growth of the migratory fish being cultured.

[0005]

[Purpose of the Invention] The present invention has been proposed in order to suitably solve the above-mentioned problems inherent in fish cage nets. The purpose is to provide a network.

[0006]

[Means for Solving the Problems] In order to overcome the above-mentioned problems and achieve the intended purpose, the present invention is characterized in that nickel-titanium alloy wires are knitted into a net.

[0007]

[Embodiments] Next, the fish cage net according to the present invention will be described below by giving preferred embodiments. The cage net according to the embodiment is made of a nickel-titanium (Ni-Ti) alloy wire rod, for example, a wire rod with a wire diameter of 8 mm (No. 8 wire) is meshed with the required mesh (depending on the type of fish to be cultured). By organizing it into a net for fish preserves. It is preferable that the wire be electrolessly plated with copper in advance to prevent shellfish and seaweed from adhering to it.

The nickel-titanium alloy used in this embodiment is a shape memory alloy that generally exhibits superelastic behavior below the reverse transformation completion temperature. However, in this example, this was not adopted to take advantage of the shape memory effect and superelastic effect specific to nickel-titanium alloys, but rather the fish cage nets were used for their wear resistance, corrosion resistance against seawater, and strength. This is because it overcomes all the conditions required for. That is, nickel-titanium alloys have wear resistance that is about eight times that of stainless steel alloys, and also have corrosion resistance that will not be corroded even if they are immersed in seawater for a long period of time. Also, in terms of strength, it is extremely strong compared to other mesh wires, so it can be made thinner than metal wires used in conventional meshes. Furthermore, when copper plating is applied to a nickel-titanium alloy wire, the metal ions produced by the copper component prevent shellfish and seaweed from adhering to the wire, ensuring good seawater flow at all times.
Moreover, it has low toxicity, so it does not have any negative impact on the ecosystem.

[0009]

As explained above, since the fish cage net according to the present invention is made of a nickel-titanium alloy, it has wear resistance, corrosion resistance against seawater, and sufficient strength. Therefore, the frequency of accidents such as the net being torn during use as a fish tank and the farmed fish escaping can be extremely reduced, and the economic damage suffered by businesses can be effectively avoided. In addition, if the wire is copper plated,
Since adhesion of shellfish and seaweed can be prevented, the circulation of seawater can always be maintained in a good manner.

Claims (2)

[Claims] 1. A net for a fish cage, characterized in that the net is formed by knitting wire rods of nickel-titanium alloy. [Claim 2] The nickel-titanium alloy wire includes:
2. The fish cage net according to claim 1, which is coated with electroless copper plating.