JPH0442800B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fish and shellfish swimming blocking device that blocks swimming of fish and shellfish in seawater when cultivating fish and shellfish.

[Conventional technology]

Traditionally, when cultivating fish and shellfish, nets are strung out in seawater to form cages, and aquaculture is carried out within the cages, but the nets that form the cages are easily damaged, so it takes a lot of effort to preserve the nets. This requires a lot of labor and expense, making it unsuitable for large-scale aquaculture such as on ocean farms.

Therefore, the applicant has proposed a device as shown in FIGS. 7 and 9, for example.

First, in Fig. 7, 1 is six vertically long conductive electrodes with a circular cross section, which are placed at each vertex of a regular hexagon when viewed from above in seawater, and 2 is for electric screen generation. It is an AC power source, and every other electrode 1 is connected to one end of the power source 2 via a connecting wire 3a, and another connecting wire 3 is connected to the other end of the power source 2.
The remaining electrodes 1 are connected through b, and a voltage is applied by a power source 2 so that the polarity of adjacent electrodes 1 is different, and an electric screen is formed between each electrode 1, and the screen causes each electrode 1 to have a different polarity. Swimming of fish and shellfish inward and outward is blocked.

At this time, for example, if the distance between two adjacent electrodes 1 is L, the distribution of electric field strength in a vertical section including both electrodes 1 will be as shown in FIG. The electric field strength at this position is very high, and when it is a certain distance from both electrodes 1,
The electric field strength remains almost constant. However, the 8th
The horizontal axis in the figure indicates the distance from the center of one electrode 1 to the center of the other electrode 1.

Next, in FIG. 9, 4a is a first electrode row, in which a plurality of vertically elongated conductive electrodes 5a with a circular cross section are arranged in seawater at intervals L', and each electrode is connected to a connecting body. 5a are electrically connected to each other to form a first electrode row 4a.

4b is a second electrode row, in which, like the first electrode row 4a, a plurality of vertically elongated conductive electrodes 5b with a circular cross section are arranged at intervals L′ in seawater, and each The electrodes 5b are electrically connected to each other to constitute a second electrode row 4b, and both electrode rows 4a, 4
b are arranged in parallel.

6 has both ends connected to both electrode rows 4 via the above-mentioned both connectors.
This is an AC power source for generating an electric screen connected to electrodes 4a and 4b, and the power source 6 connects both electrode arrays 4a and 4.
An alternating current voltage is applied between the two electrode rows 4a and 4b.
An electric screen is formed between them, and the screen blocks the swimming of fish and shellfish.

At this time, the distribution of isoelectric lines obtained by connecting equipotential points in the cross section perpendicular to each electrode 5a, 5b is as shown in the dashed line in FIG. The electric field strength distribution in a vertical section including the electrodes 5a and 5b has a pattern similar to that shown in FIG. The intensity distribution is as shown in FIG. 10, and the electric field intensity at a position close to both electrodes 5a is very high, and is almost 0 at a position intermediate between both electrodes 5a. However, the horizontal axis in FIG. 10 indicates the distance from the center of one electrode 5a to the center of the other electrode 5a.

[Problem that the invention seeks to solve]

By the way, when cultivating fish and shellfish by using the inside of each electrode 1 as shown in FIG. Then, due to the high electric field strength in the vicinity of electrode 1, fish F may receive strong electrical stimulation and become paralyzed or fatal, and there is a problem in that cultured fish and shellfish are damaged by electrical stimulation in the cage. There is.

Therefore, it may be possible to apply a voltage from the power supply 2 to the extent that even if the farmed fish and shellfish approaches the electrode 1, it will not receive strong electrical stimulation, but in this case, the electric field strength at the intermediate position between the adjacent electrodes 1 The above-mentioned problem cannot be solved by adjusting the applied voltage of the power source 2, since the voltage becomes too low and the screen no longer functions as an electric screen.

In addition, both electrode rows 4a and 4b in FIG.
are arranged to surround a specific area with the first electrode array 4a inside, for example, and when cultivating fish and shellfish in the specific area as a cage, both electrode arrays 4a, When a fish F approaches the electric screen between electrodes 5a and 4b, it receives strong electrical stimulation before entering the electric field screen due to the high electric field strength near the electrode 5a, and the cultured fish and shellfish receive electrical stimulation in the cage. There is a problem that it can be damaged by.

Therefore, the technical object of the present invention is to prevent damage to cultured fish and shellfish caused by electrical stimulation in areas within the cage other than the electric screen, without impairing the function of the electric screen.

[Means for solving problems]

This invention has been made with the above-mentioned points in mind, and consists of arranging a plurality of elongated conductive electrodes at approximately equal intervals in the vertical direction in seawater, and connecting each of the power sources with a power source for generating an electric screen. A fish and shellfish swimming blocking device that applies a voltage to generate an electric screen between the electrodes to block the swimming of fish and shellfish,
The swimming blocking device for fish and shellfish is characterized in that the cross section of each of the electrodes has a shape having two or more types of curvature radii.

[Effect]

Therefore, according to the present invention, a plurality of conductive electrodes that are vertically elongated and whose cross sections have two or more types of radii of curvature are arranged in seawater, and each conductive electrode is A voltage is applied to the electrodes to form an electrical screen between each electrode.

At this time, since the cross section of the conductive electrode was shaped to have two or more radii of curvature, the electric field strength near the electrode due to voltage application is higher near the electrode surface with a large radius of curvature than near the electrode surface with a small radius of curvature. By appropriately arranging electrode surfaces that are small and have a large radius of curvature on desired sides, fish and shellfish can be damaged by strong electrical stimulation in areas other than the electric screen, without impairing the swimming-blocking function of the electric screen. This will be prevented.

〔Example〕

Next, this invention will be described in the first part showing its embodiment.
This will be explained in detail with reference to FIGS.

(First Example) First, FIGS. 1 to 3 showing the first example will be described.

In FIG. 1, the same symbols as in FIG. 7 indicate the same things, and the difference from FIG. 7 is that electrode 1 is replaced with
The conductive electrode 7, which is elongated in the vertical direction and has an oblong cross section with two types of radii of curvature, is arranged with the electrode surface having a large radius of curvature facing inside, that is, on the cage side.

At this time, for example, as shown by the solid line, one-dot chain line, and two-dot chain line in FIG.
If R2 and R3 (R1<R2<R3) and the distance between both electrodes 7 is L as in the case of FIG. 7,
The potential distribution and electric field strength distribution in a vertical cross section including both electrodes 7 are shown in FIGS. 3a and b, respectively, and in each figure, the solid line, one-dot chain line, and two-dot chain line correspond to the radius of curvature in FIG. 2, respectively. R1, R2,
It corresponds to the electrode surface of R3. However, Fig. 3a,
The horizontal axis of b indicates the distance from the center of one electrode 7 to the center of the other electrode 7, and FIG. 3a shows the potential of the other electrode 7 as a reference. do.

As can be seen by comparing the solid line and the two-dot chain line in Figure 3a and b, the larger the radius of curvature of the electrode surface, the more constant the potential gradient becomes at all points, and the more uniform the electric field strength becomes. The electric field strength near the electrode decreases as the radius of curvature increases.

Therefore, as shown in FIG. 1, by arranging the electrode 7 having an oval cross section with the electrode surface having a large radius of curvature facing the cage, the cultured fish F in the cage can be placed in the first position.
Even if the fish F approaches the electrode 7 as indicated by the arrow in the figure, the electrical stimulation that the fish F receives in the vicinity of the electrode 7 is significantly reduced compared to the case shown in FIG. Damage caused by electrical stimulation inside the cage is prevented.

By the way, between each electrode 7, the radius of curvature of the opposing surface of each electrode 7 is smaller than that on the fish tank side, and is about the same as in the case of FIG. The anti-swimming function is not impaired.

(Second Embodiment) Next, FIGS. 4 to 6 show the second embodiment.
The diagram will be explained.

In FIG. 4, the same symbols as in FIG. 9 indicate the same things, and the difference from FIG. 9 is that the electrodes 5a, 5b
Instead, conductive electrodes 8a, 8 elongated in the vertical direction are oval in cross section and have two types of radii of curvature.
b constitutes third and fourth electrode rows 9a and 9b,
The point is that the electrodes 8a, 8b are arranged so that the radius of curvature of the opposing surfaces of the electrodes 8a, 8b in each of the electrode rows 9a, 9b is large. In addition, the dashed-dotted line in FIG. 4 shows the distribution of equipotential lines in the cross section orthogonal to each electrode 8a, 8b.

At this time, as shown by the solid line, one-dot chain line, and two-dot chain line in FIG. ′, R3′ (R1′<R2′<R3′), and if the distance between both electrodes 8a is L′ as in the case of FIG. 9, the potential distribution in the vertical section including both electrodes 8a is and the electric field strength distributions are shown in Figure 6a and b, respectively, and in each figure, the solid line, one-dot chain line, and two-dot chain line represent the electrodes with the curvature radii R1', R2', and R3' in Figure 5, respectively. It corresponds to the surface. However, the horizontal axes in FIGS. 6a and 6b indicate the distance from the center of one electrode 8a to the center of the other electrode 8a.

As can be seen by comparing the solid line and the two-dot chain line in FIG. is low, almost 0,
The electric field strength near the electrode decreases as the radius of curvature increases.

Therefore, as shown in FIG.
b, and if a fish tank is formed by enclosing a specific area with the third electrode row 9a inside, for example, the cultured fish F in the cage will be placed between both electrode rows 9a and 9b as shown by the arrow in FIG. Even if the fish F approaches the electric screen, the electrical stimulation that the fish F receives in the vicinity of the electrode 8a is significantly reduced compared to the case shown in FIG. Previous electrical stimulation damage is prevented.

By the way, between both electrode rows 9a, 9b, the radius of curvature of the opposing surface of each electrode 8a, 8b is smaller than that on the cage side, and is about the same as in the case of FIG. 9 described above. The electric screen's ability to prevent fish and shellfish from swimming will not be impaired.

Note that, of course, the cross-sectional shape of the conductive electrodes 7, 8a, 8b is not limited to the oval shape described above.

〔Effect of the invention〕

As described above, according to the fish and shellfish swimming blocking device of the present invention, since the cross section of the conductive electrode has a shape having two or more types of curvature radius, the electric field intensity near the electrode due to voltage application is The area near the electrode surface, which has a larger radius of curvature, is smaller than the area near the surface, and by appropriately arranging the electrode surface with a large radius of curvature on the desired side surface, it can be It is possible to prevent fish and shellfish from being damaged by strong electrical stimulation in the area, and the effect is extremely large.

[Brief explanation of drawings]

1 to 6 show an embodiment of the fish and shellfish swimming blocking device of the present invention, FIG. 1 is a cutaway plan view of the first embodiment, and FIGS. 2 and 3 are explanations of the principle of FIG. 1. Figure 2 is a schematic diagram, Figures 3a and b are potential distribution diagrams and electric field strength distribution diagrams, respectively, and Figure 4
The figures are cutaway plan views of the second embodiment, Figures 5 and 6.
The figure is a diagram explaining the principle of Figure 4, Figure 5 is a schematic diagram, Figures 6a and b are potential distribution diagrams and electric field strength distribution diagrams, respectively, and Figures 7 and 9 are compared with this invention. FIGS. 8 and 10, which are cut-away plan views of the fish and shellfish swimming cutoff device, are electric field strength distribution diagrams in FIGS. 7 and 9, respectively. 2, 6... Power source, 7, 8a, 8b... Conductive electrode.

Claims (1)

[Claims] 1. Arranging a plurality of elongated conductive electrodes in seawater at approximately equal intervals in the vertical direction, and applying voltage to each of the power sources using a power source for generating an electric screen to generate an electric screen between the electrodes; A fish and shellfish swimming blocking device for blocking swimming of fish and shellfish, characterized in that the cross section of each of the electrodes has a shape having two or more types of curvature radii.