HUT71356A - Method for immobilization or extirpation of larvae swimming in water and electric trap for carrying out said method - Google Patents

Abstract

A trap for swimming larvae in fresh water is constituted by two capacitor plates for influencing a mass of fresh water between the plates. An alternating current flowing in the interior of the larvae is able to kill the larvae, and the power dissipation of the trap is limited substantially thereto, while the effect of heating up the mass of water is avoided, since fresh water is a poor conductor. Therefore, it is sufficient with a voltage generator which supplies a relatively low power, i.e. a relatively high voltage but a limited current. In a method where the trap is used, a concentrated electric power dissipation of an immobilizing or killing magnitude is caused in the interior of the larvae. The interior of the larvae is constituted substantially of an electrically highly conductive liquid, and when an alternating electric field is established in the water between the capacitor plates, there will be an alternating polarization of both water mass and larvae, and an alternating current is caused inside the larvae.

Description

EXTRACT

The method of the invention is for immobilizing or killing larvae floating in freshwater masses. In the process, a concentrated dissipation of electric energy in the electrically conductive fluid which substantially fills the interior of the larvae is induced to immobilize or kill the larvae and to create an alternating electric field in the water on insulated condenser plates 1 on opposite sides of the water body (4). by means of a low-power, high-voltage AC generator connected alternately to the capacitor plates (1, 2), polarizing the water mass (4) and the larvae, thereby generating alternating current in the larvae.

The invention also relates to an electric trap for carrying out the above process. An electric trap with an electrical insulating layer (3) ^x placed on the opposite side of the body of water (4), with a low power 2 »··« high voltage, connected to an alternating current field generating an alternating electric field in the body of water (4) 4) and by means of alternating polarization of the larvae, there are two capacitor plates (1, 2) which produce a concentrated dissipation of electric energy in the larvae and thus an alternating current in the larvae.

(Figure 3)

Procedure for immobilizing or killing freshwater larvae and performing an electric trap

JAC <A'LarsVOSTLIE, Stratford upon Avon,

United Kingdom · ίτ l

Inventor:

V 'T' ·· · '

LarsVOSTLIE,

Stratford upon Avon,

Great Britain. F L>

Date of (international) filing: 02.04.1992

ζ í A v- YC 0 · '-l-J- i 1 · <' P /. cl, ('111 3 · A) ftjC

International Application Number: PCT / N092 / 00061

International Publication Number: WO 92/17061

78191-1935 VO ♦ ·

The present invention relates to a method for immobilizing or killing larvae floating in freshwater masses. The invention also relates to an electric trap for carrying out this process.

The process of the present invention allows for the inactivation or killing of larvae without the use of a chemical (poison) which is environmentally beneficial and is also suitable for the treatment of large volumes of water. Such systems are important for, among other things, the water supply connections on which freshwater organisms such as shells are deposited.

These difficulties are usually overcome by methods employing chemicals. This means that poison is injected into the system at a suitable location (such as the water supply connection). This poison may be in the form of liquid (liquefied chlorine), gas (ozone) or solid particles floating in water, gradually dissolving. For most of these chemical systems, some or all of the poison returns to the water supply tank. Therefore, the concentration of the poison increases gradually, which is unacceptable for the environment. To counteract this effect, systems have been introduced in which the poison is neutralized (for example by using clay) or unstable toxins (such as ozone) are decomposed in a short time.

However, it is preferable to completely exclude such environmental effects. It has been found that electrical effects can also be applied to influence floating organisms. In this regard, the state of the art contains little literature. Studies have been carried out on the behavior of certain organisms in a DC electric field (ie near a DC conductor) and, to a certain extent, the effects of a magnetic field have also been investigated. The effect of the AC electric field on larvae and other macroorganisms is relatively less studied.

Μ. Kirpichenko's experiments in Russia showed that a relatively weak electric field (7-10 V / cm) exposed larvae over a long period (30-50 hours), depending on the temperature of the water, reduced larval deposition and high (90% - above).

Extensive investigations have also been carried out in Russia, which resulted in plant power plant facilities. During the experiments, water was passed through an electrostatic filter of 220-450 V, 50 Hz, depending on the stage of development of the larvae. In general, it has been found that larvae must be exposed for at least 1 s to kill, but this time can be reduced by changing the shape of the pulse.

An electric field application system for electrolysis is also known to prevent deposits, which is described in the patent application of Mitsubishi (Japan). The problem with such an electrolysis system is that the electrodes are in direct contact with water, and therefore a high current flows, which

mainly heats the water. The operating costs of such a system are therefore generally high.

Fishing gear for use in salt water is known from Norwegian Patent Nos. 83 894 and Swedish Patent Specification 140 958 and German Patent Application Publication No. 1,073,629, which use pulsed current, that is, AC components superimposed on a direct current, such as aim at killing or stunning fish. Very high voltages are used, and since salt water is a good electrical conductor, high currents are flowing, so a generator supplying electrodes to the water must be capable of delivering high electrical power.

Immobilization or killing of larvae in freshwater is also desirable, preferably using an alternating electric field that does not require large-scale dissipation of energy in salt water.

The invention is based on the study of the behavior of floating larvae, in particular the causes of their behavior in electric fields. It has been observed that the larvae 's swimming behavior and other activity is affected when there is a change in the surrounding electric field. The direction of the helix-like swimming pattern changes, and this observation, together with the observation of larvae (floating) placed in a magnetic field, shows that the larvae are arranged longitudinally relative to the direction of the field. In other words, the larvae get polarized when they enter the field. This is not natural but induced ♦

- 5 polarity.

The conditions in and around the larvae in terms of electric field depend on the larval physiology and how the electric field is applied. The reason that direct current flows around the larva and not through the larva is due to the physiological conditions of the materials on the larval surface. It is obvious that the conductivity of the larvae surface is significantly lower than that of the larvae material, since the larvae interior is largely (> 90%) composed of highly conductive water.

The difference between the behavior of a larva in a permanent and alternating electric field is that larvae in a permanent and permanently applied electric field for a limited period of time are not particularly affected, while alternating fields can cause death. In the first case, the reason is that the applied DC electric field tends to create an opposite field inside the larva. When this opposite field is created, energy is transported within the larval body, that is, current flows, but as it occurs, a steady state develops, with no effect on the inside of the larva, only on the outside, due to its swimming characteristic field forces. The larval forces may be dragging the larva to the starting point of the electric field. This may explain the theory that using a weak electric field may increase the deposition rate.

- 6 If the applied electric field is changed, the larval polarity will also change, that is, there will be a current in the larval body to produce a field opposite to the applied field. In this process, internal energy transport takes place in the larval body. This (pulse-like) change in the field also affects the larval electrical system (nervous system pulses), which is a determining factor for larval activity, including swimming.

Accordingly, the present invention provides a method for immobilizing or killing larvae that float in freshwater. The process involves generating a concentrated dissipation of electric energy in the electrically conductive fluid that substantially fills the interior of the larvae by immobilizing or killing the larvae, and providing an alternating electric field in the water to insulate the capacitor disposed on opposite sides of the water body. , by means of a low-power, high-voltage AC generator alternating the body of water and the larvae by polarizing and thereby generating alternating current in the larvae.

The invention will now be described in more detail with reference to one embodiment and the accompanying drawings.

Fig. 1 shows a homogeneous electric field between two insulated plates 1 and 2 (capacitor) where the insulating layer 3 has very low susceptibility.

Figure 2 shows the mass of water 4 introduced between the two plates 1 and 2 (capacitor) of Figure 1.

Figure 3 shows the opposite field formed by polarization in the water body 4.

Figure 4 shows a reduced electric field in the water body 4.

Figure 5 shows (a) conductive particles (i.e. larvae) of a non-polar type, which (b) become polarized by induction in an electric field and are therefore arranged in the direction of the field.

Fig. 6 shows an apparent arrangement of polar larvae in a body of water 4 exposed to an electric field.

The larvae are most simply considered as conductive particles initially distributed in low-conductivity freshwater (condenser theory). The process of the present invention can be carried out in connection with water supply connections in fresh water, which contains larvae of freshwater snails. The principle of the invention is based on a system of two metallic insulated sheets 1 and 2 (capacitor) placed in freshwater (Fig. 1), wherein the insulating layer 3 surrounding the sheets 1 and 2 (capacitor) is very thin and has low susceptibility field is only slightly polarized.

Freshwater between plates 1 and 2 (capacitor) is considered to be a dielectric, i.e. an insulator with a small or limited amount of free electrical charge. The conductivity of pure water is very low. If impurities get into the water, they can increase conductivity. Most contaminants in freshwater consist of non-conductive material such as sludge and microscopic sand particles (clay), but may contain conductive materials such as dissolved metal ions.

According to the above, the larvae have a conductive interior, but their surface layer has very low conductivity. From the outside, larvae are therefore considered to be polarizable particles. However, due to their conductive interior, larvae can be considered as conductive particles under transient conditions.

Therefore, for the purposes of the present invention, the water mass 4 between the condenser plates 1 and 2 can be considered as a dielectric and the larvae are non-polar and conductive particles.

By creating a strong electric field in the body of water 4 (Fig. 3), the water molecules are polarized, creating poles in the opposite direction of the field, thus creating an opposite field in the water between the plates 1 and 2 (capacitor). The larvae also form such polar particles, and when the opposite field is generated, energy transport takes place inside the larva, that is, from one side to the opposite side, ions move as shown in Figure 6, and current flows inside the larva. Due to the forces represented by the electric field, the largest opposing field is created in the longitudinal direction of the larva and forces the larva to be arranged relative to the direction of the field. In this way, the larva rotates as long as it is located along the power lines of the electric field and the opposite field occurs in the longitudinal direction of the larva, where the value of the voltage drop is greatest. In this way,

The larvae, which are regarded as pes particles, attempt to short circuit the 1 and 2 (capacitor) plates.

Using alternating high-power electric fields and short, sharp pulses, the larvae will alternate energy transport between the two sides. The opposite field inside the larva, with its associated current, affects the activity of the larva and can kill the larva.

The distance between the plates 1 and 2 (capacitor) and the size of the plates 1 and 2 (capacitor) can be calculated by calculating the required voltage, pulse width, and frequency. These parameters depend on the conditions of the water body 4, in particular the conductivity of the water (i.e. the density of the larvae), the flow rate of the water through the volume in question and the like. The size of the field applied is generally well below the level at which corona discharge can occur, i.e. below the level of electrical breakdown and discharge.

The method described allows only relatively little energy to be used for deactivating and / or killing the larvae, since most of the energy dissipation takes place within the larvae body (meaning internal energy dissipation), while only a small amount of energy is lost in water. This is in contrast to the systems mentioned above, where high current is flowing through the water at high potentials to kill larvae, and at the same time, significant power loss occurs due to high current. This energy is used to heat the water.

Claims (5)

Claims CLAIMS 1. A method for immobilizing or killing larvae floating in a freshwater mass, comprising concentrating dissociated electrical fluid in a volume of water that substantially immobilizes or kills the larvae in the electrically conductive fluid that substantially fills the interior of the larvae; (1, 2) generates an alternating electric field in the water through a low-power, high-voltage AC generator connected alternately to the condenser plates (1, 2), alternating polarizing the water mass (4) and the larvae, thereby generating alternating current within the larvae. Method according to claim 1, characterized in that it is carried out in a pulsed alternating electric voltage. Electric trap for freshwater larvae for carrying out the process according to claim 1, characterized in that it is a low-power, high-voltage, alternating water-based (4) power supply with an electrical insulating layer (3) disposed on opposite sides of the water body (4). There are two capacitor plates (1, 2) connected to an alternating current generator, alternating polarization of the water mass (4) and the larvae, to generate a concentrated dissipation of electric energy in the larvae and thereby generate an alternating current in the larvae. Electrical trap according to claim 3, characterized in that a capacitor plate (1, 2) is connected to the pulse generator. An electric trap according to claim 3 or 4, characterized in that it comprises a capacitor plate (1, 2) insulated with an insulating layer (3) of a material of low electrical susceptibility. For Lars OSTLIE, the agent is: danubia public patent ^ ve ^ ticket office ltd.