WO2005072522A1

WO2005072522A1 - Insect control device

Info

Publication number: WO2005072522A1
Application number: PCT/GB2005/000335
Authority: WO
Inventors: Colin Peter Smith
Original assignee: Rentokil Initial Plc
Priority date: 2004-01-30
Filing date: 2005-01-31
Publication date: 2005-08-11
Also published as: GB0401982D0

Abstract

The present invention relates to insect control and provides an apparatus which performs insect attraction and killing. An attractant is emitted from the device in the environnent about the device. The attractant is carbon dioxide which may additionally contain a further chemical attractant such as octenol. Insects, such as mosquitoes, are attracted by the attractant and move down a concentration gradient towards the source of the attractant. An insecticide is intermittently released from the device (16). The expulsion of the insecticide is directed to an area about the local periphery of the device. This intermittent, directed expulsion of insecticide from the device results in the insects which have been attracted towards the device by the attractant being exposed to the insecticide.

Description

"Insect Control Device"

Field of the Invention The present invention provides a device for the control of insects, in particular the mosquito. The present invention further provides a method of controlling the release of an insecticide or insect repellent composition in a defined manner. The invention further provides a method of attracting and killing insects such as mosquitoes.

Background of the Invention Blood-sucking (haematophagous) flying insects include species such as the mosquito. Many of these insects have characteristic patterns of activity. For example, midge species found in Scotland are generally more active at dusk and in particular, during the warmer months of the year. Mosquitoes are generally found in habitats which provide either running water, transient water such as flooded areas and ditches, permanent water or contained water. Biting insects are common in many countries and the spread of blood-borne diseases such as malaria has been attributed to the prevalence of these insects .

A less serious consequence of the haematophagous nature of these insects is the irritation caused to those who have been bitten. Bites may be painful and reactions such as itching and swelling of the dermis are commonplace, in some cases lasting for days after the initial bite. In addition, the mere presence of these biting insects can provoke anxiety and disquiet in those liable to be attacked.

Many means are available to prevent biting by haematophagous insects. For example, citronella is commonly used as an insect repellent, either applied directly to the body or released into the atmosphere. Aerosol sprays for manually controlled release of chemicals that kill or disable these biting insects from pressurised canisters are also available.

However, certain species of biting insects travel in large swarms and thus the localised release of an insect repellent or insecticide has little effect on such large numbers. Other insects travel as single individuals and thus the release of repellents or insecticides needs to be constantly altered to target the flight of the insect. Large quantities of repellents and insecticides are wasted through such undirected use. International Patent Application Publication No WO 2004/082376 relates to a device for the release of an insect attractant to draw flying insects into the vicinity of the device. The attracted insects are then sucked into a collection means such as a bag located within the the device. However, the device must be manually activated and the collected insects must be disposed of. Manual disposal of the insects contained within the capture means has the disadvantage that insects collected within the collection means may not be dead. This can potentially result in the insects biting the person who is emptying the collection means .

It would therefore be advantageous to have an automated means of killing or incapacitating insects which are attracted to the insect capture device. Such means would allow the killing or incapacitation of insects attracted to the attractants expelled by the device, but would effect incapacitation in a manner other than the localised capture of the insects within the device. Such an alternative means of incapacitation would overcome the problems associated with emptying and disposing of live insects captured within the device.

The inventor of the present invention has surprisingly found that the killing or incapacitation of insects by an insect attraction and killing device can be improved through the automated expulsion of an insecticide into the environment immediately surrounding the device, the automated expulsion being triggered by predetermined stimuli.

Description of the nvention According to a first aspect of the present invention there is provided a device for attracting and killing insects said apparatus including; a source of carbon dioxide; an exhaust means from which the carbon dioxide is exhausted about the periphery of the device; a source of insecticide contained within means for expelling the insecticide about the periphery of the device.

Preferably the release of the insecticide is triggered by predetermined stimuli which result in the expulsion of insecticide from the device.

The triggered expulsion of insecticide may be continuous. However, preferably the expulsion is intermittent, such that insecticide is expelled from the device in a non-continuous manner.

Preferably the insecticide is released into an area surrounding the device which is substantially in register with the carbon dioxide exhausted from the device.

Where the insecticide is released from an aerosol container, that aerosol may be directed in a direction outward or substantially outward from the device, preferably towards an area where attractant has be emitted from the device. The aerosol expels insecticide in a specific direction. In order to vary the direction of outflow of the aerosol, the aerosol may be rotated. Alternatively a plurality of aerosol containers may be used such that insecticide is expelled in multiple directions in order to provide a cloud of insecticide substantially about the periphery of the device.

Preferably the carbon dioxide is emitted from the device through an exhaust means which exhausts the gas in an upwards direction.

Where the attractant is emitted from the device in an upwards direction, preferably the insecticide is expelled in an upwards, substantially upwards or lateral direction.

The device may also preferably include a top shield for reducing dissipation of attractant exhausted from the apparatus, wherein the top shield is positioned in spaced relationship above the exhaust means.

In one embodiment, as the attractant is emitted from the device, it may be directed against an anti- dispersal means which deflects and changes the course of the carbon dioxide following its emission from the device. This change of course or ^λflow path' can serve to create a plume of carbon dioxide about a local area of the periphery about the device. The formation of this carbon dioxide plume serves to create a high area of carbon dioxide concentration which serves to attract insects towards the device. Preferably the emission of the insecticide from the device is directed to the area where the carbon dioxide plume is formed, or about the periphery thereof, such that the insecticide expelled towards or substantially towards the area of localised carbon dioxide.

Carbon Dioxide Source The carbon dioxide source may be any suitable source of carbon dioxide. For example, the carbon dioxide source may be a pressurised canister of carbon dioxide. Alternatively, the carbon dioxide can evaporate from a source of dry ice. Preferably the carbon dioxide is produced by the combustion of a mixture of gas and air, most preferably in the presence of a catalyst.

Preferably the gas is a hydrocarbon gas such as propane, butane or a suitable mixture thereof.

The gas is preferably stored within a container and discharged via a 37mb pressure regulator. The gas container is preferably stored within the device in a self-contained housing. The gas preferably enters the combustion chamber through a nozzle which controls gas flow and pressure.

The skilled reader will be aware that the regulated pressure of gas supplied from containers may vary in different countries and therefore modifications to the nozzle may be required to obtain effective functioning of the apparatus . Such modifications will be obvious to the skilled man. For example, with a regulated pressure of 37mb, a nozzle size of 0.3mm is suitable to allow sufficient gas to feed into the combustion chamber for a power requirement of 0.25kW.

Typically, the nozzle housing has at least one hole to permit the flow of gas into the system to allow complete combustion. Complete combustion means that no hydrocarbons are included in the gas which is exhausted from the apparatus .

Preferably the carbon dioxide is mixed with air prior to being exhausted from the apparatus. The apparatus preferably further includes a suction means for drawing air into the apparatus.

The air to be mixed with the carbon dioxide is typically drawn into the device via the suction means. Typically when the carbon dioxide is produced from the combustion of a mixture of gas and air, the carbon dioxide is exhausted as a mixture of carbon dioxide, air and water vapour. Combustion typically takes place within a combustion chamber, which is preferably manufactured from cast aluminium.

Preferably the suction means, for the suction of air, is provided by a venturi arrangement. For the purposes of the present invention a venturi arrangement is defined as an opening which narrows, causing a build-up of pressure sufficient to draw air into the apparatus of the invention.

Catalyst The catalyst is preferably one which allows the combustion of gas and air without a flame and which, when operating at full working temperature, results in the release of carbon dioxide. The catalyst is preferably in the form of a monolith block.

Preferably the catalyst is a substrate coated with at least 200m²/g platinum. The greater the surface area of the catalyst, the better the performance of the catalyst at comparable precious metal content.

Pelleted catalysts have a lower surface area (< 100m²/g) than coated substrates (>200m/g) as the pellets are packed together reducing the available surface area. Coated substrates such as that of the present invention have a greater resistance to higher temperatures and against contaminants. They also contain oxygen storage compounds making the combustion process easier to initiate than beaded catalysts. For example, ignition within the present apparatus typically requires only one spark.

The catalyst has the advantage that it has better resistance against high temperatures. The catalyst typically burns in the region of 500°C to 1500°C. The ability to withstand high combustion temperatures means that contaminants such as carbon monoxide are not produced so that carbon deposits from the hydrocarbon gas source do not build up on and detrimentally affect the functioning of the catalyst .

A wide range of catalysts are known in the art and a suitable catalyst will be known to the skilled man.

The catalyst is typically housed in a chamber.

Carbon Dioxide Exhaust Preferably the carbon dioxide concentration immediately following combustion is between 6000 to 12000 ppm at a temperature which is preferably in the region of between 160°C to 210°C. More preferably the carbon dioxide is exhausted at a concentration of between 8000 to 10000 ppm carbon dioxide at a temperature of 190°C.

In one embodiment of the present invention, the carbon dioxide mixture is exhausted from the apparatus at a concentration of between 500 to 10000 ppm, more preferably between 600 to 7000. Most preferably the carbon dioxide mixture is exhausted at a concentration of approximately 4600 ppm.

The temperature of the carbon dioxide mixture on exhaustion from the apparatus may be at a temperature of between 22 and 45 °C, preferably between 24 and 42°C. Most preferably the temperature of the carbon dioxide mixture is maintained at between 10 to 15 °C above ambient temperature (i.e. above the temperature of the surrounding atmosphere) .

Preferably the carbon dioxide mixture is exhausted from an exhaust pipe, or similar outlet means, through the exit port.

Preferably the outward flow of the exhausted carbon dioxide is effected by at least one fan. The fan may suitably be a 40mm fan.

The exterior end of the exhaust pipe may be oriented in any direction suitable for the attraction of insects. Preferably the exterior end of the exhaust pipe is oriented in an upwards direction. The gaseous attractant mixture is therefore preferably exhausted upwardly.

An output of approximately 4600 parts per million (ppm) carbon dioxide at a temperature 10-20°C above ambient temperature is preferred. An output velocity of between 3 to 3.5 km/h or 1.5 to 2 mph is also preferred. This level of output ensures that the denser carbon dioxide does not sink immediately upon exhaustion.

Preferably an insect attractant is added to the carbon dioxide prior to it being exhausted. Alternatively, a cartridge containing the insect attractant is located near to the exterior exit port of the exhaust means. Preferably the attractant is an insect sex attractant pheromone. More preferably the attractant is octenol (l-octen-3-ol) . Alternatively, the attractant is octanol, octonal, 1-heptanol, 3-octanol or the like.

The inventor has therefore provided a device for insect control which performs insect attraction and killing without the need for the insects attracted to the device to be sucked into or internalised by the device.

According to a second aspect of the present invention there is provided a device for the controlled intermittent release of an insecticide, the device including a dispensing means which effects the release of insecticide, and wherein the device will automatically release insecticide in response to stimuli or when predetermined parameters are met .

Preferably the dispensing means are programmable such that automatic release of the insecticide occurs when the predetermined parameters are met.

Preferably the predetermined parameters or stimuli are defined by the pattern of activity of the insects desired to be killed, incapacitated or disabled by the device. These parameters or stimuli are preferably environmental parameters such as specific humidity, temperature, level of light, the detection of insect flight path, but may also include other parameters such as time of day or a combination of these parameters .

When the dispensing of the insecticide is, for example, to be triggered by a predetermined light level, the release may be triggered by measurement of light by a photocell.

Preferably the dispensing means includes a container, for example a pressurised container, which contains an insecticide or the like and a means for inducing the release of the insecticide from the container via, for example an aerosol or atomiser serving to dispense droplets of insecticide from the device.

Alternatively the insecticide may evaporate from a solid or liquid source.

The insecticide may be any suitable means for disabling or killing insects, and in particular mosquitoes . Preferably the insecticide is a chemical insecticide.

The device may be used for the killing and/or disablement of any insect. Preferably the insects are haematophagous flying insects . More preferably the insects are mosquitoes.

In a preferred embodiment the device may additionally include a means for attracting insects, for example an attractant. The attractant may be any suitable insect attractant such as lights and/or heat or a combination of both, but is preferably a chemical attractant. Such chemical attractants include inter alia carbon dioxide, l-octen-3-ol, octenol, and pheromones .

Preferably the attractant is carbon dioxide or a gaseous mixture containing carbon dioxide, most preferably heated carbon dioxide. The carbon dioxide may be provided from a contained source or be produced as a product of the combustion of gas such as butane or propane.

More preferably heated carbon dioxide is further mixed with a second chemical attractant prior to the expulsion of the mixed attractant from the device. Most preferably the secondary attractant is octenol.

The attractant may also be dispensed in a controlled manner by a programmable dispensing means. This programmable dispensing means may be linked to or separate from that used to dispense the insecticide.

In a further preferred embodiment the device of the present invention may be incorporated within a known device of the prior art. For example, International PCT Publication No WO 2004/082376 describes an insect trapping device which uses expelled carbon dioxide mixed with a secondary chemical insect attractant, as an attractant to lure insects towards the device. Modification of this prior art device with the present invention will result in the modification of the device such that insect capture is not required, but rather release of insecticide into the atmosphere, preferably in a programmable automated fashion causes death or incapacitation of insects attracted by the expelled attractant. This results in much increased efficiency of the device.

In such an arrangement, insects are thus attracted towards the device and killed in the vicinity of the unit. The arrangement provided by the present invention overcomes the disadvantage of the insects, which are drawn into the device prior to their being killed, having to be removed from the insect collection bag within the device. As mentioned above, this collection and disposal step of insects caught within the device is not desirable, particularly when live mosquitoes are caught, as the insects may not be dead and therefore potentially hazardous to the unit operator, while the disposal of dead insects from the bag can be unpleasant. Preferably the expulsion of the insecticide from the device is solar powered. Alternatively, the expulsion of the insecticide from the device is powered by a battery, which may be charged by solar power or through a mains connection. In a further alternative embodiment, the expulsion of the insecticide from the device is powered by a heat cell. For example, a thermo-electric generator (TEG) may be driven by the heat which is a bi- product of gas combustion where combustion is used to produce carbon dioxide.

An example of a suitable battery would be a 1.2V 1500mA hour battery. Such a power source may be expected to run a motor continuously for 10 hours, releasing insecticide four times an hour, eight hours per day. The release of insecticide takes, for example, 8 seconds and thus the release time per day would be approximately 4.5 minutes per day. Such a battery may therefore last for around 120 days .

According to a third aspect of the present invention there is provided a device for the controlled release of insecticide for use in killing and/or disabling insects, the device including: - means for attracting insects; and - means for dispensing insecticide, wherein the means for dispensing the insecticide can be programmed such that the insecticide is dispensed automatically when predetermined parameters are met.

The insecticide may be any suitable means for disabling or killing insects, and in particular mosquitoes. Preferably the insecticide is a chemical insecticide.

The attractant may be any suitable insect attractant, but is preferably a chemical attractant. Such chemical attractants include inter alia carbon dioxide, l-octen-3-ol, octenol, and pheromones . The predetermined parameters which, when met result in insecticide release are defined by the pattern of activity of the insects desired to be killed or disabled by the device. For example, such parameters may include a time of day, a specific humidity, temperature or level of light, or a combination of these parameters . When the dispensing is, for example, to be triggered by a predetermined light level, the release may be triggered by measurement of light through a photocell.

Preferably the insecticide is contained in a pressurised container, which is activated to allow release of insecticide following programmed release. Said arrangement allows the insecticide to be propelled out of the canister by an aerosol propellant such as compressed gas.

Alternatively the insecticide can be dispensed as a through means, for example, a diffuser.

According to a fourth aspect of the present invention there is provided a method of killing insects, the method including the steps of: - releasing an insect attractant into the vicinity of the insect killing device ; and - programming the device to automatically expel an insecticide into the vicinity of the device when predefined parameters are met.

Preferably the insecticide is expelled into an area surrounding the device which is substantially in register with the area into which the insect attractant is expelled.

Preferably the insects attracted by the insect attractant are haematophagous flying insects . More preferably the insects are mosquitoes.

Preferably killing insects includes the incapacitation or disabling of insects.

The attractant may be any suitable insect attractant, but is preferably a chemical attractant. Such chemical attractants include inter alia carbon dioxide, l-octen-3-ol, octenol, and pheromones .

The predetermined parameters which, when met result in insecticide release are defined by the pattern of activity of the insects desired to be killed or disabled by the device. For example, such parameters may include a time of day, a specific humidity, temperature or level of light, or a combination of these parameters. When the dispensing is, for example, to be triggered by a predetermined light level, the release may be triggered by measurement of light through a photocell.

Preferably the insecticide is contained in a pressurised container and released via an aerosol, which is activated to allow release of insecticide following programmed release.

The present invention further provides for the use of a device according to the present invention in the attraction and killing of insects .

Preferably the insects are mosquitoes.

Preferably the mosquitoes are attracted through the use of carbon dioxide and / or another suitable chemical attractant such as octenol.

Preferred features of each aspect of the invention are the same for each other aspect mutatis mutandis unless the context demands otherwise.

Unless otherwise defined, all technical and scientific terms used herein have the meaning commonly understood by a person who is skilled in the art in the field of the present invention.

Throughout the specification, unless the context demands otherwise, the terms * comprise' or 'include', or variations such as 'comprises' or 'comprising', 'includes' or 'including' will be understood to imply the inclusion of a stated integer or group of integers, but not the exclusion of any other integer or group of integers .

Description of the Figures

The present invention will now be described by way of example only with reference to the accompanying non-limiting examples and further with reference to the accompanying figures, which are provided for the purposes of illustration and are not intended to be construed as being limiting on the present invention. In the figures; Figure 1 shows a schematic of the device for the programmed release of insecticide, Figures 2 to 8 show alternative means for the mechanical dispensing of insecticide, Figures 9 and 10 show alternative means for the dispensing of insecticide involving use of a solenoid, Figure 11 shows an example of an embodiment of the insect killing device of the present invention, and Figure 12 shows a representation of the combustion chamber of the device.

Detailed Description of the Invention EXAMPLE 1 Insecticide Expulsion Means Figure 1 shows an embodiment wherein a device 2 of the invention is powered by solar power, which is detected by a solar cell 4 and stored via a charger 6 in a battery 8. The battery is connected to an intermediate component 10 including a controller, timer and a CPU. The intermediate component 10 is controlled by a photocell 12 such that release of insecticide from a container 16 is programmed to detect the level of daylight. The component 10 is also connected to a spray mechanism 14. The spray mechanism 14 is conjoined to a container 16 of insecticide. The insecticide is preferably contained in an aerosol or pressurised canister. This is preferably interchangeable to allow replacement and exchange.

Figures 2 to 6 show alternative mechanical spray mechanisms 14 for use in the invention. This mechanism results in the release of insecticide from the aerosol or storage container. Figure 2 shows a cam 18 whose rotation is used to depress a release button 20 on the container 16. Means of rotating the cam 18 such as a DC motor are not shown. An example of a suitable motor is a 3V DC motor geared to provide appropriate torque running at around 7.5 rp .

Gearing may be required for generating sufficient torque to cause depression of the button 20. The distance that the release button 20 must be depressed is indicated by the symbol x. It is important that the profile of the cam 18 progressively extends to a distance equal to the summation of the distance from the axis of rotation 21 to the top of the button 20 (y) and the value x. Although for clarity, the cam 18 is shown as separated by a gap in Figure 2, this gap would typically not be provided. Rotation of the cam 18 180° to that shown in Figure 2 is sufficient to depress the release button 20 allowing the release of insecticide from the container 16 through an opening 22 by standard means known in the art. Control means for activating and deactivating the mechanism are not shown.

Figure 3 shows two rack and pinion arrangements, A and B. Arrangement A shows a rack 24 and a pinion 26 located above the release button 20. Control means for activating and deactivating the mechanism are not shown. However, on activation the pinion 26 is rotated, this rotation being driven for example by a motor. The engagement of the teeth of the pinion 26 with the grooves on the rack 24 causes the rack 24 to move. Clockwise rotation, as indicated by arrow 28, causes downward movement of the rack 24 as indicated by arrow 30 and thus depression of the release button 20. This allows the release of insecticide from the container 16 through the opening 22. Arrangement B shows an alternative rack and pinion arrangement. An assembly 32 comprises the container 16, the release button 20, and the rack and pinion assembly 34 which are contained within a framework 36, shown in cross section. The rack 24 is mounted on the lower surface of a platform 40 located at the base of the container 16. Clockwise rotation of the pinion 26 causes the rack 24 to move upwards, pushing the platform 40 upwards into contact with the base of the container 16. The upwards movement of the platform 40 pushes the container 16 upwards until the release button 20 contacts the top surface 38 of the box 36 and is depressed, causing release of the insecticide as described previously.

An alternative to the framework 36 is a bar in place of the top surface 38 of the framework positioned to come in contact with the release button 20 on activation of the device.

The two rack and pinion set ups shown in A and B may require gearing for producing sufficient torque as well as means of rotating the pinion 26 in both directions . Electronic control means for controlling the direction and travel of a motor are well known in the art.

Figure 4 shows a snail cam mechanism, in two positions, a first, deactivated position A and a second, activated position B. A shaft 42 is connected to a snail cam 44. A motor (not shown) or similar means causes rotation of the shaft 42 in the direction indicated by arrow 46. Gearing (not shown) is provided for torque. The rotation of the shaft 42 in turn causes rotation of the snail cam 44 causing its enlarged end 44A to contact and depress the release button 20, as shown in B. Insecticide is released from the container 16 as described previously. As the motor continues to drive rotation of the shaft 42, the enlarged end 44A is moved from contacting the release button 20 to the position shown in A, terminating release of the insecticide. A control (not shown) is also provided to activate and deactivate the device.

Figure 5 shows an alternative means for depressing the release button 20. Control means (not shown) for activation and deactivation of the device is provided. A motor (not shown) causes rotation of a starter handle 48 and in turn rotation of a shaft 50. Rotation of the shaft 50 causes the spring 52 to be released from forcible contact with the shaft 50 and to enter contact with the release button 20. The spring 52 is released with sufficient force as to cause depression of the release button 20, inducing release of the insecticide from the container 16 as described above. The necessary force to permit depression of the release button and permit release of insecticide would be in the region of 3kg.

The starter handle 48 is rotated in the reverse direction to raise the spring 52 from contact with the release button 20 and into the position shown in Figure 5, ready for re-release on re-activation.

Figure 6 shows a further alternative means for depressing the release button 20. Similar to the cam mechanisms shown in Figure 1, rotation of a motor (not shown) causes a lever arm 54 to exert a downward force on the release button 20. The mechanism requires a control means (not shown) for activation and deactivation. On activation, the motor causes rotation of a wheel 56 in the direction as shown by arrow 58. Gearing (not shown) may also be provided for generating sufficient torque. A shaft 60 fixed to the wheel 56 thus comes into contact with the elongate arm 54A of the lever 54, causing its displacement as shown by arrow 64. The displacement of the arm 54A causes rotation of the lever 54 about a fixed pivot point 66 . This rotation in turn induces the enlarged end 54B of the lever 54 to exert a downward force (indicated by an arrow 70) on the release button 20. The depression of the release button 20 caused by the downward force 70 results in release of the insecticide from the container 16.

Figure 7 shows a sixth means for mechanical depression of the release button 20. The depressing means is composed of a drive nut 72, which is driven along the length of a threaded shaft 74 by a motor 76. A gear box 78 provides the necessary torque. Control means (not shown) control the activation and deactivation of the mechanism. On activation, the motor 76 causes rotation of the threaded shaft 74, inducing downward movement of the drive nut 72 along the shaft 74. After a defined distance, for example 3 mm, the nut 72 is brought into contact with the release button 20. Subsequent movement of the nut causes depression of the release button 20 to cause release of the insecticide from the container 16.

When the nut 72 has moved the defined distance, the drive nut 72 also contacts an end stop 80A which prevents excessive downward displacement of the drive nut 72, and thus of the release button 20. Contact of the drive nut 72 with the end stop 80A activates a microswitch 82A which causes a reversal in the direction of the motor 76. The shaft 74 then rotates in the opposite direction, causing upward movement of the drive nut 72 along the length of the shaft 74. This reverse rotation of the nut 72 eventually results in full retraction of the release button 20 and thereafter movement of the drive nut 72 away from the release button 20. This has the effect of preventing further release of the contents of the container 16. When the nut 72 has travelled sufficient distance along the shaft 74, a further end stop 80B prevents further displacement of the drive nut 72 and activates a further microswitch 82B which emits an electronic signal causing the motor 76 to stop. Figure 8 shows two alternative mechanisms (A and B) for depressing the release button 20. Both mechanisms involve the use of a solenoid.

On activation of the mechanism shown in Figure 8A, the solenoid 84 forces an activating bar 86 down into contact with the release button 20. As the activating bar 86 is pushed further down a downwards force is exerted on the release button 20 causing its depression and thus the release of insecticide from the container 16. On deactivation, the magnetism of the solenoid 84 is switched off and biasing means (not shown) causes the activating bar 86 to be returned to the normal position, thus removing the downward force from the release button 20.

In Figure 8B a lever 88 is attached to a shaft (not shown) at its end 88A proximal to the solenoid 84. On activation, the shaft is drawn into the magnetised coil of the solenoid 84. The lever 88 then pivots about a pivot point 90 causing a downward force to be exerted by the other end 88B of the lever 88 on the release button 20. Insecticide is thus released as described above. Deactivation results in the reverse movement of the components.

Figure 9 shows a side view A and a front view B of a further solenoid-driven means for depressing the release button 20. The container 16 of insecticide is positioned within a U-shaped framework 92. The framework 92 is composed of two vertical plates 92A, interconnected by a base plate 92B. A slot 94 extends longitudinally along the top end of each of the vertical plates 92A. A depressing means, in this case a bar, 96 is held at each of its ends within the slot 94 and slides along the length of the slot 94 during use of the device.

A supporting means, in this example a bar, 98 is fixed within the framework 92 at its base. The container 16 is supported at its base by the supporting means 98. The solenoid 84 is located below the supporting means 98 at the base of the container 16. An activating means 86 has an elongated portion 86A and a head portion 86B attached to the elongated portion 86A. The elongated portion 86A extends at its base end into the magnetised coil of the solenoid 84 and at its upper end through the base plate 92B of the framework. The head portion 86B is therefore located on the upper surface of the base plate 92B.

On activation, the solenoid 84 draws the elongated portion 86A of the activating means 86 down into the magnetised coil of the solenoid 84. This downward movement pulls the framework 92 downward by exerting a downward force on the base plate 92B. The depressing means 96 then slides along the slot 94 towards the base of the framework 92. The depressing means 96 thus comes into contact with the release button 20 and exerts a downward force on it. Insecticide is then released from the container 16 through the opening 22 as described above. An alternative embodiment is shown in Figure 10. Figure 10B shows an enlarged view of the base of the device shown in Figure 10A. A weighted depressing means, in this example a bar, 96 rests on the release button 20 when in deactivated mode. However, the weight of the depressing bar 96 alone is not sufficient to cause depression of the release button 20. When a solenoid 84 is activated a head portion 86B of the activating means 86 exerts a force on the load bar 102. The force is transferred to load struts 100A and 100B (not shown) which pull downward on the depressing bar 96 and thus an additional force is exerted on the release button 20, as described for the embodiment shown in Figure 9. The additional force is sufficient to cause release of the insecticide from the container 16.

The type and strength of solenoid used for the reaction will be obvious to one skilled in the art. An example of a suitable solenoid would be a 30W 5V latching solenoid, the permanent magnetic holding force being 2.2Kgf. A capacitor may be used to facilitate activation of the solenoid.

EXAMPLE 2 Alternative means of dispensing insecticide

As an alternative to the propellant driven, aerosol expulsion of the insecticide as described above, the insecticide may be dispensed by means of a diffuser which allows for the dispersion of insecticide into the local environment. The insecticide may diffuse from a gel or sponge soake in insecticide or a card soaked with insecticide. Alternatively the insecticide may evaporate from a volatile liquid. Alternatively, the insecticide may be provided as a combination of sources such as a gel and volatile liquid.

The diffuser may be battery operated or driven by an electric supply, which may be sourced from a mains supply or from a light solenoid or a heat cell.

EXAMPLE 3 nsect attraction and capture

In a preferred aspect of the present invention, the attractant expelled from the device is provided by carbon dioxide which results from the combustion of gas such as propane or butane.

In such an embodiment, the container which retains the insecticide is located within the device and serves to expel insecticide into the local environment about the device in the region where the emitted carbon dioxide is located.

An example of such an apparatus is shown in figure 11. Said apparatus 110 has a combustion chamber 12 housing a chamber which contains a catalyst 154. A thermocouple is located inside the combustion chamber 112 and is in contact with the catalyst chamber. A spark igniter is also located inside the combustion chamber 112. The base of the combustion chamber 112 is mounted on a venturi arrangement housed within a nozzle housing 120. A jet carrier 124 is located at the base of the nozzle housing 120. A gas nozzle 122 is also provided at the base of the combustion chamber 112. A sintered disc (not shown) is located between the gas nozzle 122 and the combustion chamber 112.

An exhaust chimney 126 houses an exhaust pipe. The thermoelectric generators 130 are arranged between the outer wall of the combustion chamber 112 and a heat sink 132. A heat plate 156 is used in conjunction with heat transfer pins 158 to assist in thermal conductivity of the heat generated from combustion to the hot side of the thermoelectric generators 130. The heat pins 158 are provided above and below the catalyst 154 to ensure effective heat transfer through to the heat plate 156 and thus to the thermoelectric generators 130. The high thermal conductivity of the cast aluminium combustion chamber 112 further assists in heat transfer to the thermoelectric generators 130.

The heat plate 156 is generally made of aluminium but may be made from copper. It is generally approximately 3mm thick.

The combustion chamber 112, thermoelectric generators 130 and heat sink 132 are housed in a first outer housing 134. A vapour shield (anti- dispersal means/top shield) 138 is mounted above the exhaust pipe.

A service panel 142 is provided on the first outer housing 134. A multi-spark ignition switch 144 is situated on the service panel 142. An air vent 166 is also located in the first outer housing 134. The first outer housing 134 is mounted on a second outer housing 146, which houses a gas cylinder (not shown) .

The apparatus 110 may be mounted on wheels to facilitate movement of the device.

In use, a gas cylinder (not shown) is housed within the second outer housing 146. A safety valve button 160 is activated to draw gas from the gas cylinder through the nozzle 122 and sintered disc into the combustion chamber 112. The venturi arrangement simultaneously draws air into the combustion chamber 12. The ignition switch 144 is depressed, activating the spark igniter and causing the gas and air mixture to ignite. A temperature differential thus builds up between the combustion chamber 112 and the heat sink 132. The gas mixture burns until the oxygen in the air is used up and the catalyst 54 reaches its working temperature of 350°C (measured on the top surface of the active catalyst; the temperature of the inside of the catalyst can reach up to 800°C) . The gas is now burnt completely by catalytic conversion producing steam and 8000 - 10000 ppm carbon dioxide at 190°C (i.e. at the exhaust chimney 126, directly above the combustion chamber 12) . A power indicator 168 indicates that the apparatus has reached this stage.

When the temperature differential between the combustion chamber 112 and the catalyst chamber is sufficiently high, the thermocouple lproduces a voltage which holds the safety valve open. The temperature differential is sufficient when a voltage of 5 millivolts is generated. The safety valve button 160 may then be deactivated.

The heat from the operational catalyst 154 is transferred via the heat pins 158 and plates 156 through the walls of the combustion chamber 112 to the thermo-electric generators 130, which are connected to an electrical output and which convert the temperature differential between the combustion chamber 112 and the heat sink 132 into a voltage which is used to drive the inlet and outlet fans 162,164. The voltage required to activate the fans is approximately 3 volts. The inlet fan 162 helps maintain the temperature differential between the combustion chamber 112 and the heat sink 132.

The outlet fan 164 mixes the carbon dioxide produced from combustion and the air drawn in through the suction means, and forces the mixture up the exhaust pipe and out through the exhaust outlet 126. The carbon dioxide/water vapour/air mixture leaves the exhaust outlet 126 at a concentration of 800 to 5000 ppm carbon dioxide and at a temperature in the region of 10 to 15°C above ambient temperature, ambient temperature being between 15 to 25°C, for example 20 to 22°C.

A cartridge 152 containing an insect attractant, such as octenol, can be placed at the exit of the exhaust pipe. When octenol evaporates from the cartridge 152, it mixes with the carbon dioxide/water vapour/air mixture, forming an insect- attracting vapour.

The warmth of the carbon dioxide mixture causes the gaseous mixture to rise up from the exit port of the exhaust pipe. Such plumes of attractant are vulnerable to dissipation caused by air currents such that insects are not optimally attracted.

However, the vapour shield 138 can be positioned in a spaced relationship with the outlet of the exhaust port to inhibit the attractant vapour from dissipating from the local vicinity of the apparatus 110.

Insects attracted to the periphery of the device may be exposed to insecticide which is expelled from the device. The outlet port of the insecticide containing means, whether it be an aerosol or a diffuser is located in the area under the vapour shield. The expulsion of insecticide from the outlet can result in insecticide being present in the plume of carbon dioxide which is present in the local environment about the device. It is preferred that the expulsion of the insecticide from the device is only intermittent, that is that the insecticide will be expelled in bursts at timed intervals . This means that insecticide will not always be present about the periphery of the device, rather the constant outflow of attractant will attract insects down a concentration gradient towards the device. Once, present in this area about the device, the insecticide will be emitted and the insects attracted by the attractant will be exposed to the insecticide and incapacitated or killed.

The device can further include a safety mechanism which maintains a safe operating temperature.

The safety mechanism preferably includes a safety valve, a safety valve button, a thermocouple and a bimetallic switch. The safety valve, safety valve button, thermocouple and bimetallic switch are preferably connected in a circuit.

The safety valve controls the flow of gas into the combustion chamber. The thermocouple is preferably located such that it detects the temperature of the combustion chamber and the temperature of the chamber housing the catalyst. When the temperature differential between the two chambers is sufficiently high, a voltage flows along the thermocouple to maintain the safety valve in its open position. If the temperature in the combustion chamber drops or the catalyst malfunctions, the valve closes, thus preventing gas entering the combustion chamber.

The bimetallic switch is preferably located on the outer wall of the combustion chamber and is connected in circuit with the safety valve such that if the trapping apparatus overheats the safety valve closes . The trapping apparatus is deemed to have overheated when the temperature of the outer wall of the combustion chamber exceeds 120°C.

The apparatus may further include a multispark igniter. This is an electronic battery operated device. On depression it provides a continuous spark to the combustion chamber so as to ignite the gas/air fuel mixture.

The apparatus may also include a voltmeter or other voltage indicator to provide a visual reading of the power generated by the thermoelectric generators. For example, a red colour on a power indicator may show that the apparatus is warming up whilst a green colour could indicate that the apparatus is fully operational.

At least one exhaust vent may be provided in the walls of the combustion chamber so as to allow for free movement of the air drawn in by the fans.

All documents referred to in this specification are herein incorporated by reference. Various modifications and variations to the described embodiments of the inventions will be apparent to those skilled in the art without departing from the scope of the invention. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes of carrying out the invention which are obvious to those skilled in the art are intended to be covered by the present invention.

Claims

1. A device for attracting and killing insects said apparatus comprising; a source of carbon dioxide; an exhaust means from which the carbon dioxide is exhausted about the periphery of the device; a source of insecticide; means for expelling the insecticide into an area about the periphery of the device.

2. A device according to claim 1 wherein the expelled release of the insecticide is triggered by predetermined stimuli which result in the expulsion of insecticide from the device.

3. A device according to claim 1 or 2 wherein the expelled release of the insecticide from the device is provide in an intermittent non-continuous manner.

4. A device according to any preceding claim wherein the insecticide is released into an area surrounding the device which is substantially in register into which the carbon dioxide exhausted from the device.

5. A device according to any preceding claim wherein the insecticide is expelled from an aerosol container.

6. A device according to claim 5 wherein said aerosol container rotates in order to vary the direction of insecticide expelled therefrom.

7. A device according to claim 5 wherein a plurality of aerosol containers are used to expel insecticide in a plurality of directions outwards from the device.

8. A device as claimed in any preceding claim wherein the source of carbon dioxide is combustion of a mixture of gas and air.

9. A device as claimed in any preceding claim wherein combustion takes place in the presence of a catalyst.

10. A device as claimed in claim 9 wherein the catalyst is a platinum-coated monolith block.

11. A device as claimed in any of claims 8 to 10 wherein the gas is propane, butane or a suitable mixture thereof.

12. A device as claimed in any preceding claim wherein the carbon dioxide is mixed with air prior to being exhausted.

13. A device as claimed in any preceding claim wherein an insect attractant is added to the carbon dioxide prior to its exhaustion.

14. A device as claimed in any preceding claim wherein the carbon dioxide is exhausted at a concentration of between 500 to 10000 ppm.

15. A device as claimed in any preceding claim wherein the carbon dioxide is exhausted at approximately 4600 ppm.

16. A device as claimed in any preceding claim wherein the carbon dioxide is exhausted at between 22°C to 45°C.

17. A device as claimed in any preceding claim wherein the carbon dioxide is exhausted at between 24°C to 42°C.

18. A device as claimed in any preceding claim wherein the carbon dioxide is exhausted at a velocity of between 3 to 3.5 km/h.

19. A device as claimed in any preceding claim wherein the carbon dioxide is exhausted from an exhaust pipe.

20. A device as claimed in any preceding claim wherein the exterior end of the exhaust pipe is oriented in an upward direction.

21. A device as claimed in any preceding claim wherein the exterior end of the exhaust pipe is adapted to be directed towards the anti-dispersal means .

22. A device as claimed in any preceding claim wherein the insecticide is any suitable means for disabling or killing mosquitoes.

23. A device for the controlled release of insecticide for use in killing and/or disabling insects, the device including: - means for attracting insects; and - means for dispensing insecticide, wherein the means for dispensing the insecticide can be programmed such that the insecticide is dispensed automatically when predetermined parameters are met.

24. A device as claimed in claim 23 wherein the dispensing means are programmable such that automatic release of the insecticide occurs when the predetermined parameters are met .

25. A device as claimed in claim 23 wherein the predetermined parameters or stimuli are defined by the pattern of activity of the insects desired to be killed.

26. A device as claimed in claim 23 or 24 wherein the parameters are environmental parameters selected from the group consisting of; specific humidity, temperature, level of light, detection of insect flight path, and time of day.

27. A device according to any one of claims 23 to 26 wherein the insecticide is any suitable means for killing mosquitoes.

28. A method of killing insects, the method including the steps of: -releasing an insect attractant into the vicinity of the insect killing device ; and -programming the device to automatically expel an insecticide into the vicinity of the device when predefined parameters are met .

29. A method according to claim 28 wherein the insecticide is expelled into an area surrounding the device which is substantially in register with the area into which the insect attractant is expelled.

30. A method according to claim 28 wherein the attractant is an insect attractant.

31. A method according to claim 28 wherein the attractant is carbon dioxide.

32. A method according to claim 28 wherein the attractant is carbon dioxide in combination with at least one further chemical attractant.

33. Use of a device according to the present invention in the attraction and killing of insects.

34. Use of a device according to claim 33 wherein the insect is a mosquito.