JP2019126302A - Electrostatic field screen for pest control - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a pest which can be supplied at a relatively low cost with a simple structure and exhibits a function of ensuring sufficient ventilation and preventing the invasion of pests by installing it in an opening such as a window of a livestock barn such as a pig barn. An object of the present invention is to provide an electrostatic field screen for use. SOLUTION: Three metal nets of the same size and the same mesh of a central net 1 and outer nets 2 and 3 arranged on both sides thereof are arranged in parallel with a predetermined space between the nets, and are arranged in the center. The net 1 is negatively charged, the outer nets 2 and 3 are positively charged, and the opposite poles face each other. The applied voltage to the central net 1 is within a range in which forced discharge does not occur between the nets 1 to 3. It is characterized by being. [Selection diagram] Fig. 1

Description

  The present invention relates to electrostatic field screens for controlling insect pests, and more particularly, to electrostatic field screens for controlling insect pests suitable for use in windows of facilities for livestock (such as pig stalls) and openings of ventilation fans and the like. It is about

  In modern barn design, it is necessary to ensure adequate ventilation. And it is important that the barn be designed to remove excess heat, water vapor, dust, gas, and odors, and evenly distribute the air. Passive or natural ventilation is accomplished by supplying and removing air through the building opening. Natural ventilation occurs due to the natural wind flow around the building and the temperature difference between the inside and outside of the building. Forced ventilation occurs with a fan, an automatic temperature control device, and an air inlet, and most commonly uses a fan to blow air out of the building and fresh air from the other side to the inlet. Done by aspiration through. The fan can also be used in a facility to circulate air and improve the uniformity of ventilation properties.

  However, when ventilation facilities are sufficient, pests may be introduced into the barn. Serious pest problems in livestock production are diverse. Livestock pests feed on animal blood, skin, and hair, and pest bites can cause physical and mental health problems for animals. In addition to pest problems in livestock, there is also the concern of pest-borne transmission of pathogens from the barns to the surrounding human society. In many parts of the world, urbanization that has progressed at a rapid pace has forced the urban livestock industry to provide food to urban residents. Therefore, the risk of transmission of a common infectious disease to livestock in urban areas is becoming more and more serious.

  Thus, in the barn, it is necessary to take measures to ensure sufficient ventilation and to prevent the infestation of pests, and between these two requirements, if ventilation facilities are sufficient, the pests need to be Due to the contradictory side that it may be introduced inside, there has not been proposed a facility suitable for installation in a livestock facility such as a pig house that can simultaneously satisfy these two requirements.

Unexamined-Japanese-Patent No. 2007-195404

  As described above, conventionally, there has not been proposed any equipment suitable for installation in a stall such as a pig stall that can simultaneously satisfy the two requirements of securing sufficient ventilation and preventing the infestation of pests. Its emergence was longing for. The present invention has been made to meet such a demand, and can be supplied at a relatively low price with a simple configuration, and by installing it at the opening of a window of a barn such as a pig bar, sufficient ventilation can be secured and pests It is an object of the present invention to provide an electrostatic field screen for controlling pests that exhibits a function of preventing the entry of water.

  The inventors have found that it is possible to kill pests using high energy electrons generated in the electric field, and due to the high electrical conductivity of the pest body, only pests are electrocuted due to the instantaneously generated arc discharge in the device. As a result of intensive research and testing under the hypothesis of death, the present invention has been completed.

  That is, the invention described in claim 1 for solving the above-described problem is that three stainless steel nets having the same size and the same mesh are arranged between a center net and outer nets arranged on both sides thereof. Arranged in parallel with spacing, the central net is negatively charged, and each outer net is connected to a ground wire and electrostatically induced to be positively charged and made to face opposite poles, The applied voltage to the central net is a range in which no forced discharge occurs between the nets.

  In one embodiment, the applied voltage to the central net is less than 10.1 kV.

  In one embodiment, the mesh size of the three nets is 4 mesh or more, and the three nets are surrounded by an insulating frame.

  In one embodiment, the distance between the three nets is around 15 mm. Then, an insulating material spacer for maintaining the distance between the electrodes is sandwiched between the nets of the three nets.

  Since the electrostatic control screen for pest control according to the present invention is as described above, it can be supplied at a relatively low price with a simple configuration, and sufficient ventilation can be achieved by installing it at the opening of windows of livestock equipment such as a piggery. It is effective in securing and preventing the entry of pests.

It is a schematic diagram which shows schematic structure of the electrostatic field screen for insect pest control which concerns on this invention. It is a schematic diagram which shows the electric field in the electrostatic field screen for insect pest control which concerns on this invention. It is a figure which shows the test method performed in order to confirm the effect of the electrostatic field screen for insect pest control based on this invention. It is a figure which shows the test method performed in order to confirm the effect of the electrostatic field screen for insect pest control based on this invention. 6 is a graph showing the relationship between applied voltage under different relative humidity (RH) conditions and the magnitude of current generated by silent discharge from the central net for three different types of electrostatic field screens according to the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. As shown in FIG. 1, the electrostatic field screen for controlling pests according to the present invention is made of stainless steel having the same size and the same mesh of three pieces of the central net 1 and the outer nets 2 and 3 arranged outside thereof. Metal nets are arranged in parallel with a predetermined interval between the nets 1 to 3. The central net 1 is connected to a DC voltage generator 4 having a maximum current of 1,000 μA, for example, to be negatively charged, and the outer nets 2 and 3 are connected to the ground line 5 to be connected to the central net 1. It is configured such that it is positively charged by electrostatic induction and opposite poles face each other.

  For example, assuming that the three nets 1 to 3 are installed in the windows of a barn, the mesh size is 4 mesh or more in order to ensure sufficient air permeability, and an insulating frame such as polycarbonate etc. Surrounded by six. In addition, a spacer 7 made of an insulating material such as polypropylene having a thickness corresponding to the distance between the electrodes is interposed between the nets 1 to 3 to secure the distance between the electrodes. The inter-electrode distance is, for example, about 15 mm.

  In this configuration, since the central net 1 side is negatively charged between the central net 1 and the external net 2, the external net 2 side is positively charged by electrostatic induction. Is formed. Similarly, between the central net 1 and the outer net 3, the central net 1 side is negatively charged, so that the outer net 3 side is positively charged by electrostatic induction, and an electric field is formed between the nets 1 and 3. (See Figure 2). Arrows in FIG. 2 indicate the direction of the current.

  As mentioned above, the device according to the invention is developed under the hypothesis that only the pest will be electrocuted by the instantaneously generated arc discharge in the device due to the high conductivity of the pest body . The present inventors have confirmed that this hypothesis is correct, conducted the following test to determine the effectiveness of the device, and obtained the most appropriate condition from the test result to optimize the configuration of the device. It was decided to

Culex pipiens was used as a model vector of the test material virus pathogen. The adult mosquitoes were reared in a growth chamber under conditions of 25.0 ± 0.5 ° C., 4,000 lux and a photoperiod of 12 hours. And in the following experiment, the adult mosquito of newly emerged Culex pipiens was used. The average body size (ie, the average length from the head to the heel tip of 20 adults) was 5.6 ± 1.3 mm.

As a test device , according to the present invention, three stainless steel nets of the same size and the same mesh are arranged in parallel at predetermined intervals between the nets 1 to 3, and a DC voltage is generated at the central net 1. A device to which the vessel 4 was connected was prepared. In this test apparatus, a galvanometer 8 for measuring the movement of free electrons to the central net 1 was connected to each ground line 5 (see FIG. 1). In addition, three types of electrostatic screens having different net sizes, that is, 45 × 45 cm (S screen), 90 × 90 cm (M screen), and 180 × 90 cm (L screen) were prepared as test devices.

≪Experiment 1≫
In the first experiment, three types of screens were charged at 1 to 15 kV, and forced discharge (arc discharge) was performed from the central net 1. Further, the silent discharge (which is constantly generated on the outer net 2 and 3 side surface of the central net 1) was measured in a voltage range (2.0 to 10.0 kV) that does not cause forced discharge. The galvanometer 8 measured the current as the sum of silent discharge and forced discharge, or as pest-mediated discharge described later. The experiments were performed at 25 ° C. and under different relative humidity (RH) conditions (30, 60 and 90%).

≪Experiment 2≫
In the second experiment, the three screens are charged with different voltages (2-10 kV), and the range of voltages at which all pests introduced to the screen are electrocuted, and the pest-mediated transient current at a given voltage ( And the magnitude of the arc discharge). Culex mosquitoes, which are test insects, were collected with an insect aspirator and blown between the nets by blowing compressed air through the tip of the insect aspirator (FIG. 3). The wind speed was measured on the surface of the central net 1 using a highly sensitive anemometer.

  In these experiments, house mosquitoes were blown at a wind speed of 3-5 m (average air flow rate in a well-ventilated pig house). All experiments were performed under the above RH and temperature conditions. The galvanometer 8 recorded the pest-mediated discharge as a transient current. Culex pipiens was evaluated for mortality after passing through the electric field. Twenty adult squids were used for each voltage and RH condition tested. The experiment was repeated 5 times, data are shown as mean and standard deviation (SD), and significant differences between treatments were determined using Tukey's method.

Test Results and Examination In the above test apparatus, the central net 1 was negatively charged using a high voltage generated in the Cockcroft circuit in the voltage generator 4, and both electrodes were charged by discharging from the outer nets 2 and 3. The flow (current) of stored electricity to the central net 1 was affected by the voltage applied to the electrodes, the distance between the electrodes, and the electrical conductivity of the air between the two electrodes. The current was proportional to the increase in voltage and inversely proportional to the increase in distance. The conductivity of air changes in response to fluctuations in the concentration of water vapor (RH) in the air and becomes higher as RH increases (ie, the amount of electrical transfer increases). In this experiment, the distance between the electrodes was fixed, the voltage was changed effectively, and the squid was electrocuted by an electrostatic device under different RH conditions.

  In Experiment 1, the voltage at which forced discharge occurred from the central net 1 due to the uneven structure of the nets 1 to 3 used in the screen was measured. A forced discharge (arc discharge) occurred at a salient point on the central net 1. As the applied voltage to the central net 1 was increased, the screen resulted in a forced discharge at ≧ 10.1 kV regardless of the change in RH. As a result, it was found that at <10.1 kV, the screen can be operated without forced discharge even if there is a change in RH.

  In the electric field generated between the nets, silent discharges were continuously generated from the outer nets 2 and 3 side surface of the central net 1 toward the outer nets 2 and 3. FIG. 5 shows the relationship between the applied voltage and the generation of silent discharge. In any type of screen of different sizes, the current generated by this discharge increases in direct proportion to the increase in applied voltage, and the range of applied voltage is 6.8-10 kV, M for the S size screen. The size screen was 4.3 to 10 kV, and the size screen was 3.2 to 10 kV. The current increased as the screen net size increased. Furthermore, the current increased with increasing RH in all screens tested.

  In the electrostatic field screen according to the present invention, since it was thought that the air in the electric field was ionized by ionization, measurement was performed using an ion detector. As a result, it was found that the air in the electric field was ionized by ionization. It is also confirmed that ionized air in this electric field is very active, capable of destroying or inactivating various microorganisms including viruses, and deodorizing odorants passing through the electric field. The Various odors generated in the barn cause serious environmental problems, and the electrostatic field screen according to the present invention can be effectively used for countermeasures against the odor due to the odor removal ability.

  In the subsequent second experiment, various voltages that do not cause forced discharge from the central net 1 were used, and conductors that transmit electricity (free electrons) according to the capacity were introduced into the space between the nets of the screen. The inventors' hypothesis is that this conductor material can serve as a temporary acceptor of electrons from the central net 1 and as a donor of electrons to the outer nets 2 and 3 by reducing the distance between the electrodes. It was.

  In the test to confirm the validity of this hypothesis, the insect (Cauliflower) was a good bioconductor (Figure 4). That is, the epidermis, which is the outer protective layer covering many vertebrate bodies, is known to be efficiently charged by its high conductivity, and adults of the house mosquito have this epidermal structure. It is because

  Table 1 lists the magnitudes of instantaneous transient currents mediated by adults of C. elegans introduced into the test apparatus. The nets 1 to 3 were charged under different RH conditions with different voltages (2 to 10 kV). Once house mosquitoes are introduced, electrons move from central net 1 to outer nets 2 and 3 instantaneously, within the voltage range of 3 to 10 kV for L and M screens and 4 to 10 kV for S screens. I came to flee to the earth through. This electron transfer was simultaneously recorded as transient currents of the same magnitude by the two galvanometers 8. However, the magnitude of the current was significantly different between the screens used even when the same voltage was applied.

  These results indicate that different amounts of electricity (free electrons) accumulated in central net 1 were released towards the pests. The magnitude of the increase in current corresponds to an increase in the area of the central net 1 (that is, an increase in the capacitance of the central net 1). In all screens, the magnitude of the current became larger as the applied voltage increased. The higher the current, the greater the impact, causing the squid to fly out of the air. The RH condition did not produce any significant difference in insect-mediated transients in all screens.

  Table 1 also shows the mortality of Culex pipiens introduced on the screen. The lowest voltages that could kill all squids by blitz were 4, 6, and 8 kV on L, M, and S size screens, respectively. At these voltages, similar levels (about 20 μA) of insect-mediated transient currents are generated, and it has been found that currents of this level are necessary to effectively electrocut the insect in the electric field of the screen . At lower voltages, the generated shock was insufficient to kill the insects, as there is less accumulation of free electrons in the central net 1.

<Table 1>

  The results obtained from the above test results are as expected of the present inventors, and the device according to the present invention is applicable for preventing the escape of mosquitoes that transmit the virus from the barn. It was corroborative. It is clear that this device is also effective in preventing pests from entering the barn, that is, protecting livestock and the like from various pests. Theoretically, this pest control method can be applied to all pests having a conductive skin layer. In pest control for livestock, control of ectoparasites is one of the most expensive and time-consuming tasks, and in warmer regions, various flies are ectoparasites on animals.

  The apparatus according to the present invention is not only provided with an electric shock killing ability of pests but also can secure a sufficient opening area for ventilation by using a net having a large opening area. The mesh size of the net (e.g., about 7.0 mm) is much larger than that of the conventional woven pest net (about 0.8-1.5 mm). In addition, when this conventional woven pest net was installed in the same barn opening where the present apparatus was installed in the above experiment, naturally the ventilation efficiency was surely lowered.

  In the test apparatus, the current increased in direct proportion to the increase in applied voltage, RH (only for silent discharge), and net size in both arc discharge and silent discharge. These properties are due to the electrostatic nature of the screen. However, the magnitude of the current (20 to 200 μA) was negligible from a practical point of view. As described above, the electric field is formed between the negative charge of the central net 1 and the positive charge of the outer nets 2 and 3 on the central net 1 side. It was possible to touch the surface of the net safely. As another protection means, there is a current limiter (the maximum limit value is 1000 μA) incorporated in the electric circuit of the voltage generator 4. This is because when an excessive current is generated due to an unexpected situation, the voltage generator 4 Automatically turn it off.

  The apparatus according to the present invention can be used for efficient pest control in a barn and can eliminate the need for insecticide treatment. In addition, the device according to the present invention has a simple configuration, is easy to manufacture without requiring special technology, can be easily adjusted in size according to the installation location, and operates with low power consumption, infecting pathogen viruses. Can be used to electrically kill harmful pests, and are suitable for installation at the opening of livestock raising facilities for pest control, eliminate the need for insecticide treatment, and manage them environmentally It is possible to breed and supply animals free of viruses in a livestock facility, and its industrial applicability is extremely large.

1 Central net 2, 3 Outer net 4 Voltage generator 5 Ground wire 6 Insulation frame 7 Spacer 8 Galvanometer

Claims (6)

Three stainless steel nets of the same size and the same mesh, the central net and the outer nets arranged on both sides of the central net, are arranged in parallel with a predetermined interval between the nets, and the central net is negatively charged. , Each of the outer nets is positively charged and the opposite poles are opposed to each other,
The electrostatic field screen for controlling pests, wherein a voltage applied to the central net is in a range where no forced discharge occurs between the nets.   The electrostatic field screen for controlling pests according to claim 1, wherein an applied voltage to the central net is less than 10.1 kV.   The electrostatic field screen for controlling pests according to claim 1 or 2, wherein the mesh size of the three nets is 7 mm or more.   The electrostatic field screen for pest control according to any one of claims 1 to 3, wherein the three nets are surrounded by an insulating frame.   The electrostatic field screen for pest control according to any one of claims 1 to 4, wherein a distance between the three nets is about 15 mm.   The electrostatic field screen for pest control according to any one of claims 1 to 5, wherein a spacer made of an insulating material for maintaining a distance between the electrodes is sandwiched between each of the three nets.