GB2118815A - Insect extermination - Google Patents

Abstract

An electrically operated insect trap is designed to attract and kill nocturnal flying insects. The trap is portable and has a fluorescent tube to emit light rays of a frequency likely to attract flying insects above or below two spaced apart metal mesh members 12, 13 with an insulating separator 14 between the members. Means is provided to maintain a sufficient electrical potential difference between the metal mesh members and to energise the fluorescent tube so that an insect flying through the metal mesh members causes a short circuit and the resulting spark kills the insect. Discharge through a capacitor circuit is disclosed. <IMAGE>

Description

SPECIFICATION Improvements in or relating to insect traps This invention relates to the provision of an improved apparatus for killing flying insects especially nocturnal ones such as gnats, mosquitoes and others.

For many years it has been realised that certain types of flying insects are a great nuisance and can also be a danger not only to human beings but also to animals. There are two main avenues of approach to a solution of the problem (a) to repel them to try to keep the insects away from a predetermined position and (b) to attract the insects and then trap and/or kill them. I believe that the second method has advantages over the first method and quite a number of electric insect traps of various kinds have been proposed see e.g.

a Summary of investigations of electric insect traps by Truman E. Hienton (retired) collaborator Agricultural Research Services, Technical Bulletin No. 1498 published in 1 974 by the United States Department of Agriculture.

Among the electrical methods that have been proposed are light traps and the attraction of some adult flying insects to artificial light has been known for many years. Incandescent electric lamps produce radiation including ultra-violet rays, visible light including yellow and red light rays and infra-red radiation. I believe that many flying insects are especially attracted to ultra-violet rays which are also emitted by gaseous discharge lamps such as mercury vapour lamps and the summary of investigations mentioned above stated that the near ultra region, 320 nm-380 nm of the electromagnetic spectrum has been found to be the most attractive radiant energy to a great many nocturnal insects.

The above knowledge has been made use of commercially and several pieces of apparatus have been put on the market to trap light-sensitive nocturnal flying insects but so far as I am aware all of the commercially available devices have several serious disadvantages e.g.

1. They are all substantially static in the sense thatas a practical matter they cannot readily be packed up and taken on a journey.

2. They are relatively large and expensive.

3. They operate at high voltages between 4500 volts and 7000 volts.

In accordance with the present invention I provide a portable electrical insect trap especially for attracting and killing substantially nocturnal flying insects comprising a fluorescent light tube adapted to emit light rays of a frequency likely to attract flying insects, two spaced apart electrically conductive metal mesh members, insulating separator means between the metal mesh members to keep the members spaced apart by a desired distance, means to maintain sufficient electrical potential difference between the metal mesh members and to energise the fluorescent tube when the trap is connected to a suitable source of electrical power and an easily portable container for the apparatus.

Essentiaily therefore my insect trap includes a box containing a suitable source of ultra-violet light or other light attractant, two electrically conductive wire mesh members with an insulating separator or separators between the wire mesh members, means to connect the wire mesh members and the lamp to a source of electrical power and means to maintain an electrical potential difference of a predetermined voltage between the two wire mesh members when the electrical power is on.

The two wire mesh members are preferably of the same gauge though if desired one may be a little larger than the other and the size of the mesh openings in the wire mesh members is preferably the same but may be different if desired. The irisulating separator(s) may be made of plastics material and may be in the form of a mesh separator or may comprise several separate members suitably located and secured in position between the wire mesh members. The apparatus is operable most effectively in low ambient light conditions and the reference made above to nocturnal flying insects is intended to include not only insects who appear at night but also other insects who fly in the evening or at dusk when the ambient light is dull. In full daylight the ambient light is usually too bright to enable the lamp to attract the flying insects.

In order that the invention may be more closely understood reference is now directed by way of example to the accompanying drawings in which: Figure 1 is a diagrammatic plan view of a box suitable to hold the apparatus with the lid removed, Figure 2 is a side view of the box with the lid on, Figure 3 is an end view of the box with the lid on; Figure 4 is a plan view of the box with the lid operand with the various parts of the apparatus in position only a part being shown in full detail, Figures 5 and 6 are detail views of the metal mesh members and the insulating separator in plan and section only a part being shown in full detail, Figure 7 is a view of the electrical circuitry.

Referring to the drawings the insect trap includes a f)at shallow box 1 with a body 2 and a lid 3, preferably hingedly secured to the body 2.

The body 2 and the lid 3 have ends 4 and sides 5 and the body 2 has a bottom 6 and the lid 3 has a top 7. Figure 1 ,from which the lid 3 has been removed has a first cover portion 8 at one end to form a housing for electrical equipment and a second cover portion 9 at the other end to enclose one end of the lamp, which is not shown in Figure 1.

Referring now to Figures 4, 5 and 6 it will be seen that the apparatus includes a black light fluorescent tube 10 and a protective mesh cover 11 preferably of wire covered with an outer plastics sheath disposed above the tube 1 0. Below the tube 10 is the trap proper including two spaced apart metal mesh or grid members 12, 13 with a wide mesh spacer 14 between them. If desired the tube 10 can be below the members 12, 13 and 14. In operation the apparatus is connected to a suitable source electrical power e.g. the mains by the electrical connector 15 which energises the tube 10 to emit black light of a desired frequency and which charges the metal mesh members positively and negatively respectively so that there is a potential difference of about 1000 volts between the members.The black light emitted by the tube 10 attracts the flying insects which fly into the box. As the insects pass through the mesh members 12 and 13 they connect one grid to the other and a flash discharge of spark passes through the insect which is thereby killed instantly. It will be understood that although the voltage is relatively high, though lower than previous electrical insect traps the power is relatively low since the spark is produced by the discharge of capacitors. Preferably solid state electrical circuitry is provided below the cover 8 and one suitable embodiment of such circuitry is illustrated in Figure 7.

In accordance with a feature of this invention I find that I can place the two metal mesh members relatively close together because the insulating separating means between the metal mesh members holds the assembly in substantially fixed relative positions and this in turn permits the use of a relatively low potential difference of about1000 volts between the metal mesh members.

The invention therefore provides a re;laiveIy- small, substantially self-contained portable insect trap that can be carried in luggage or in a briefcase or handbag so that the apparatus can easily be taken on holiday or on business trips-and on arrival may be plugged into the mains and operated.

Referring to Figure 7 the electrical circuit for powering the tube 10 comprises a pair of diodes D1 and D2 connected to one side of the mains supply 1 5 in opposite polarity to develop a d.c.

potential across capacitors C1 to C4 connected to the other side of the mains supply. The tube 10 is connected in series with a resistor R1 across the capacitors C1 to C4 so that when power is applied - from the mains supply the capacitors are repeatedly discharged through the tube. The metal mesh members 12 and 13 described above are coupled to output terminals 1 6 and 1 7 of a diode pump circuit also powered from the mains supply 15.Capacitor C7 is charged via diode D5, and the voltage developed on capacitor C7 is superimposed via D4 on the vdltage developed on capacitor C8 toproduce an output voltage of approximately 1000 V across the terminals 1 6 and 1 7. Although it has been stated above that the insulating separator (5) may be made of plastics material it will be understood that any other suitable insulating material or substance may be used. Also, in the drawing the power is shown as being 240 V AC (see Figure 7) but this figure is given purely as an example to suit most UK conditions and other voltages e.g. 110 may be used as desired with suitable adaptation of the components. In fact for general use I may supply units to operate from mains power on 110-240 V AC and I also propose to provide a low voltage version to operate at e.g. 12 volts supply.

Claims (9)

1. A portable electrical insect trap especially for attracting and killing nocturnal flying insects comprising a fluorescent light tube adapted to emit light rays of a frequency likely to attract flying insects, two spaced apart electrically conductive metal mesh members, insulating separator means between the metal mesh members to keep the members spaced apart by a desired distance, means to maintain a sufficient electrical potential difference between the metal mesh members and to energise the fluorescent tube when the trap is connected to a suitable source of electrical power and an easily portable container for the apparatus.

2. An insect trap according to Claim 1 wherein the fluorescent tube is adapted to emit ultra-violet light rays.

3. An insect trap according to Claims 1 or 2 wherein a -potential difference of about 1000 volts is maintained between the metal mesh members when the trap is operating.

4. An insect trap according to any of the preceding claims wherein the metal mesh members have mesh openings of substantially the same size.

5. An insect trap according to any of the preceding claims wherein the insulating separator means is in the form of an insulating mesh member.

6. An insect trap according to any of the preceding claims wherein the container is rectangular in plan and has a housing at one end for electrical equipment and means at the other end to enciose one end of the lamp.

7. An insect trap according to any of the preceding claims wherein a protective mesh guard is provided in the container above the tube.

8. An insect trap according to any of the preceding claims wherein the metal mesh members are connected to electrical circuitry e.g: solid state circuitry arranged so that when an insect causes a short circuit a spark of relatively low power is produced by the discharge of capacitors.

9. An insect trap substantially as hereinbefore described with reference to the accompanying drawings.