Abstract:
An insect killing system optimized for mosquitoes uses multiple thermal gradients to simulate the breathing of, and body heat emitted by, animals, including human beings and fowl, to attract insects for subsequent electrocution and/or trapping. Mosquitoes are attracted to a mosquito-killing device for electrocution and/or trapping. Heat is generated within the device such that a heat gradient between an outer surface of the device and the atmosphere surrounding the device is created thereby emulating emission of body heat by an animal. At least one mosquito attractant, such as an aromatic, a pheromone, or moisture, is emitted from the device. And an airflow is created that sucks mosquitoes, which have been attracted to the outside of the device, into the device for electrocution and/or trapping by the device.

Description:
[0001]    This is a continuation of pending application Ser. No. 09/009,122, filed Jan. 20, 1998, which is a continuation-in-part of application Ser. No. 08/761,282, filed Dec. 6, 1996, now U.S. Pat. No. 6,050,025, which is a continuation-in-part of application Ser. No. 08/395,910, filed Feb. 28, 1995, now U.S. Pat. No. 5,595,018. 
     
    
     
       TECHNICAL FIELD  
         [0002]    The invention relates generally to attracting and exterminating harmful insects, in particular mosquitoes, and in particular relates to emulating certain characteristics of a mammal to attract insects for electrocution and/or trapping.  
         BACKGROUND OF THE INVENTION  
         [0003]    Insect killing devices are known in the art, see e.g. U.S. Pat. Nos. 5,255,468, 4,852,296, 4,891,904, 5,205,064, 5,020,270, 4,696,126 and 5,301,458.  
           [0004]    The conventional insect killing devices heretofore known typically use light to attract insects to an electrocution grid. Aforementioned Pat. No. 4,891,904 to Tabita discloses a heating device for heating a liquid insecticide containing carrier, such as a mat or wick, for evaporating the insecticide into the atmosphere.  
           [0005]    The known prior art devices are largely ineffective for killing mosquitoes, blood-sucking insects notorious for carrying and spreading diseases such as malaria and yellow fever, while such devices attract and kill many harmless or environmentally beneficial species of insects. A side effect of such systems is that they are prone to eventual failure as a result of clogging of the voltage grid by the remains of larger insects, which can lead to short circuits, inability of the grid to electrocute additional insects, and other failures. Systems such as disclosed in the &#39;904 patent which release toxic poisons into the air clearly are undesirable.  
           [0006]    There remains a need in the art for effectively attracting and exterminating mosquitoes, while being environmentally safe and minimizing attraction of other beneficial insects.  
         SUMMARY OF THE INVENTION  
         [0007]    The invention is directed to solving the problems discussed above. An illustrative embodiment of the invention is directed to a method of attracting mosquitoes to a mosquito-killing device for electrocution and/or trapping. The method comprises: generating heat within the device such that a heat gradient between an outer surface of the device and the atmosphere surrounding the device is created thereby emulating emission of body heat by an animal; emitting at least one mosquito attractant from the device; and creating an airflow that sucks mosquitoes, which have been attracted to the outside of the device, into the device for electrocution and/or trapping by the device. The attractant may be an aromatic, a pheromone, or moisture. Generating heat within the device may comprise: using resistive electrical conductors to generate the heat. The airflow may be directed through an electrocution grid and/or a trap within the device.  
           [0008]    Another illustrative embodiment of the invention is directed to a method of attracting mosquitoes to a mosquito-killing and/or trapping apparatus. The method comprises: emitting heat from an outer surface of the apparatus to create a heat gradient for attracting mosquitoes to the outer surface of the apparatus; simulating exhaling by an animal by emitting a gaseous flow for attracting mosquitoes to the apparatus; and creating an airflow to suck the attracted mosquitoes into the apparatus for electrocution and/or trapping by the apparatus. The gaseous flow may include: a pheromone, or moisture. Resistive electrical conductors may be used to generate heat within the apparatus. The airflow may be directed through an electrocution grid within the device.  
           [0009]    Another illustrative embodiment of the invention is directed to an apparatus that attracts mosquitoes to be killed and/or trapped. The apparatus comprises: means for generating heat within the apparatus such that a heat gradient between an outer surface of the apparatus and the atmosphere surrounding the apparatus is created thereby emulating emission of body heat by an animal; means for emitting at least one mosquito attractant from the apparatus; and means for creating an airflow that sucks mosquitoes, which have been attracted to the outside of the apparatus, into the apparatus for electrocution and/or trapping within the apparatus. The means for generating heat within the apparatus may include means for using resistive electrical conductors to generate the heat. The apparatus may further comprise: means for directing the airflow through an electrocution grid or trap within the apparatus. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    The invention disclosed herein will be better understood with reference to the following drawings, of which:  
         [0011]    [0011]FIG. 1 is an isometric view of a mosquito killing apparatus according to an embodiment of the invention;  
         [0012]    [0012]FIG. 2 is an isometric view similar to FIG. 1, but without safety guard  70 ;  
         [0013]    [0013]FIG. 3 is an enlarged view of the upper circled area of FIG. 2;  
         [0014]    [0014]FIG. 4 is an enlarged view of the lower circled area of FIG. 2;  
         [0015]    [0015]FIG. 5 is an enlarged view of the circled area of FIG. 3;  
         [0016]    [0016]FIG. 6 is an enlarged, partially phantom view similar to FIG. 5, illustrating movement of brace  66  by loosening set screw  69 ;  
         [0017]    [0017]FIG. 7 is a partially fragmented isometric view similar to FIG. 2, with portions omitted for illustrative purposes;  
         [0018]    [0018]FIG. 8 is a partially fragmented isometric view similar to FIG. 7, with portions omitted for illustrative purposes;  
         [0019]    [0019]FIG. 9 is a schematic diagram of the electrical circuitry according to an embodiment of the invention;  
         [0020]    [0020]FIG. 10 is a partial cross-sectional view of a mosquito killing apparatus according to an embodiment of the invention; and  
         [0021]    [0021]FIG. 11 is a partially broken view of a motion pole used in conjunction with the embodiment of FIG. 10. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]    Referring more specially to the drawings, my improved mosquito killing system is generally designated by reference numeral  20 . System  20  attracts mosquitoes  22  by actively projecting multiple infrared heat gradients and pressure differentials coupled with a wide variety of aromatics that simulate animal body heat and breathing.  
         [0023]    System  20  comprises an elongated, generally parallelepiped housing  25  disposed upon a convenient supporting surface  26  (FIG. 1). The housing comprises a rectangular support base  30  and a spaced apart, truncated pyramidal roof  40  (FIGS.  1 - 2 ). The roof closes the tower interior. A switch  32  and photoelectric sensor system  34  control system operation, as discussed hereinafter. A pilot light  42  physically protrudes form roof  40  to indicate the operational status of system  20 .  
         [0024]    The roof  40  is secured to an internal heating tower  50  extending between the base  30  and the roof  40 . A conventional bolt  45  extends through roof  40  to mate with a conventional nut  40 . A cross member  48  secures roof  40  to tower  50  and base  30 .  
         [0025]    The tower  50  conducts air drawn into the base  30  into the upper portion of the housing and then forcefully projects it outwardly. A vertically oriented electrocution grid  60  is fixed to the outer perimeter of the tower  50 . An outermost, safety wire mesh guard  70  surrounds the tower. It extends between the base and the roof to prevent accidental contact with the interior electrocution grid  60  or other internal components. An annular region  71  is defined between the guard  70  and tower  50 ; this region is traversed by mosquitoes  22 ,  22 A (FIG. 1) passing through the guard. Several spaced apart terminal loops  72  and conventional screws  74  removably secure guard  70  to the base  30  and roof  40 . The wire mesh comprises several vertically aligned, parallel, spaced apart stringers  76  reinforced by several parallel, regularly spaced apart horizontal cross members  78 .  
         [0026]    The base  30  preferably comprises a hollow, parallelepiped casing  80  (FIGS.  2 ,  7 - 8 ) that supports the housing  35 . The casing  80  rests on plate  82 . Casing  80  is penetrated by a plurality of intake orifices  83  for first admitting air into the system in response to fan suction. These preferably slit-shaped orifices  83  are regularly spaced about the casing periphery  84  for admitting air into the system. One slit  83  exposes a moist wick  85  to the exterior of the device. A scent drawer  90  also penetrates casing  80 .  
         [0027]    The scent drawer  90  contains gel  92  that simulates common smells attractive to mosquitoes or to the target insect. The gel  92  gradually releases pheromones (represented by dashed lines  98 ) into the casing interior  86  for mixture with the entering air currents (represented by dotted lines  108 ). Wick  85  supplies moisture (represented by dotted and dashed lines  88 ) to the casing interior, where it is mixed with the entering air currents  108 . Casing interior  86  serves as a mixing chamber where the entering air  108  is intermixed with aromatics  98  and moisture  88 .  
         [0028]    An internal fan  100  forcefully draws air  108  through the slits  83  and into the casing  80 . Preferably, the fan  100  has a relatively low volumetric output rate, in the range of ten to twenty cubic feet per minute (cfm), most preferably fifteen cfm. As air  108  is suctioned into the apparatus it is turbulently mixed with released aromatics  98  and emitted moisture  88  in the casing interior  86 . Fan  100  is secured to plate  82  adjacent transformer  102 . Preferably, the fan blades  105  are positioned immediately adjacent the tower bottom  58 . Air forced upwardly by the fan is directly forced into the heating tower  50  and eventually rises to top  54 . The resultant tower air stream is represented generally by arrows  118  (FIG. 8).  
         [0029]    The tower  50  preferably comprises an elongated tubular conduit  110 , preferably with a rectangular cross-section. The external surface  112  of the conduit  110  is obscured by electrocution grid  60 . A plurality of spaced apart braces  64 ,  65 ,  66 ,  67  and  68  secure the electrocution grid to two elongated, vertically oriented parallel rods  62  and  63  that are parallel to the longitudinal axis of opposite tower corners  52  and  53 . Of course, tower  50  could be cylindrical or another configuration as long as vertical air flow through tower  50  remains.  
         [0030]    An internal, perforated baffle  115  divides the tower  50  into adjacent, lower and upper tubular sections  120  and  130  respectively (FIG. 8). Tower section  120  defines an enclosed heating chamber  125  The upper tower section  130  defines an adjacent dispersal chamber  135 . In effect the baffle  115  comprises a restrictor plate between the chambers that affects the internal tower airflow  118 . It establishes an internal pressure differential between the chambers. Because of the preferred baffle design, denser, warmer air in the lower chamber is at a higher pressure than air above. The tower air pressure differential, and the temperature and pressure gradients established with the preferred construction I have detailed are important. These synergistically enhance the ability of the system to emulate the infrared signature of a live, breathing animal that is attractive to insects. In other words, I have found that this arrangement produces infrared images that simulate the presence of breathing animals, including human beings, fowl and the like.  
         [0031]    The lower tower section  120  houses an elongated, cylindrical, resistive electric heater  122  that warms air within the heating chamber. Baffle  115  restricts the upward airflow to ensure that the residence time of the air  118  in the lower section  120  is adequate to heat the air sufficiently (preferably to a temperature between 100 and 120 degrees Fahrenheit). Preferably, heater  122  centrally extends along the longitudinal axis of section  120  between bottom  58  baffle  115 . Heater  122  is supported at one end by a strut  124  extending across bottom  58  above fan  100 . The opposite end of heater  122  is supported by brace  115 .  
         [0032]    This turbulent air  118  is heated as it travels past heater  122 . A thermostat  126  controls the operation of heater  122  by monitoring tower temperature. Thermostat  126  is preferably mounted adjacent baffle  115  with its thermostatic element in thermal contact with the tower. Of course, the extent to which the air is heated depends upon prevalent external environmental conditions, as will be discussed more thoroughly hereinafter.  
         [0033]    Baffle  115  increases the internal tower pressure differential. As air  118  flows up conduit  110 , baffle  115  restricts its flow. Several holes  116  penetrate the plate  117  comprising baffle  115 . These holes  116  permit air  118  to eventually cross into top section  130 . Consequently, the pressure of the air (indicated by arrows  128 ) entering the upper section  130  is increased by the restriction of baffle  115 . Thus, heated air  128  both a higher temperature and a higher pressure than entering air  108 .  
         [0034]    Air  128  entering the upper section  130  is eventually dispersed into housing  25  and the immediately surrounding area. As air  128  enters the upper section  130  from the bottom section  120 , it flows through a plurality of regularly spaced apart discharge orifices  132  penetrating the upper section walls  134 ,  135 ,  136  and  137  beneath the roof. The discharge orifices pass heated, slightly pressured air outwardly in small turbulent streams (as indicated by arrows  138 ). The air streams  138  emitted from the orifices into the housing are strongest within the interior annulus  71 . The multitude of air streams established thereby create the appearance of animal breathing. In addition there are thermal and pressure gradients surrounding the housing  25 . These gradients additionally simulate human breathing, and the resultant thermal pattern attracts mosquitoes who mistake it for the infrared signature of an animal, including a human being, fowl or the like.  
         [0035]    Attracted mosquitoes  22  are electrocuted (i.e., mosquito  23  shown in FIG. 3) when they approach the tower  50  by the electrocution grid  60  surrounding the exterior conduit surface  112 . The electrocution grid  60  comprises a vertically oriented wire network  150 . Multiple spaced apart electrically conductive stringers  152  extend downwardly from top brace  64  and main line  151  with corresponding spaced apart electrically conductive stringers  154  protruding upwardly from bottom braces  68  (FIGS. 4 and 7A). A plurality of staples  155  secure both main lines  151 ,  153  to respective braces  64  and  68 .  
         [0036]    The downwardly oriented and upwardly oriented stringers  152  and  154  alternate. In other words, an upward stringer  154  extends between each downward stringer  152  (FIG. 7A). Whenever an object touches a downward and an upward stringer  152  and  154 , it creates a short circuit that electrifies the object, such as mosquito  23 .  
         [0037]    After electrocution, the insects (i.e. mosquitoes) are generally disintegrated. Other remains generally fall toward the base  80  where they are typically swept away by winds, etc. However, when necessary, the middle braces  65 ,  66  and  67  may all be manually manipulated to clean the grid  60 . A set screw  69  normally retains the braces in place. Set screw  69  tightens against rod  62  or  63  to secure the brace  64 - 68 . Set screw  69  may be loosened to move braces  65 ,  66  or  67  upwardly or downwardly to clean stringers  152  and  154  as shown in FIG. 6. A groove  160  extending through braces  65 ,  66  and  67  receives the stringers  152  and  154 . The stingers  152  and  154  slide along the grooves  160  with lip  162  removing any debris thereon.  
         [0038]    With primary emphasis now directed to FIG. 9, the preferred electrical control circuit has been designated by the reference numeral  200 . Nominally 120 volt A.C. voltage is supplied to the circuitry with a standard three-prong plug  201 . Voltage is transmitted across input lines  203 ,  204  through fuses  205 A and  205 B. Switch  32  may be user selected to apply power directly to tilt-over safety switch  170 . Alternatively, switch  32  may direct voltage via photoelectric switch system  34  to switch  170  or it may be switched “off”. System  34  automatically energizes and controls the apparatus depending upon ambient light conditions. Safety tilt-over switch  170  disables the apparatus when the tower is tipped over approximately thirty degrees from vertical.  
         [0039]    Voltage applied to node  206  is applied to a thermostat-controlled switch  126 . Switch  126  applies voltage to node  207  to energize both motor  100  and resistive heating element  122 A. Voltage on node  206  also energizes the primary  208  of high-voltage transformer  102 . As long as there is voltage across nodes  206 ,  206 B the pilot light  42  will be energized as well. High voltage outputted from the transformer across lines  151  and  153  electrifies the electrocution grid  60  previously discussed.  
         [0040]    For best results the device should be operated during the night. It should be placed away from humans. During daylight hours it is preferably placed in the shade. During operation system  20  attracts mosquitoes  22  by projecting air  138  outwardly from tower  50 . Air  138  comprises a mixture of moisture  88 , aromatics  98  and heated and pressurized air  128 . The projected air  138  creates several thermal and pressure gradients around housing  25  that simulate human breathing and body heat. The aromatics  98  and moisture  88  further enhance the simulation of a live animal such as a human or fowl.  
         [0041]    The system  20  first draws air  108  into base  30  through several slits  83  as a result of the operation of a fan  100 . Of course switch  32  must be activated. As air  108  enters the casing interior  86 , it mixes with aromatics  98  escaping from drawer  90  and moisture  88  from wick  85 . The mixed air is then blown upwardly into heating tower  50 .  
         [0042]    As the blown air  118  enters the tower section  120 , it passes an electric heater  122 . Heater  122  warms air  118  to a preselected temperature as determined by thermostat  126 . The heated air  118  is also slightly pressurized by baffle  115  as it moves into dispersal chamber  130 .  
         [0043]    Air  128  moving into chamber  130  is projected outwardly through several orifices  132 . As air leaves chamber  130 , it begins cooling and depressurizing as it moves outwardly. Cooled and depressurized air  138  establishes multiple thermal and pressure gradients once outside tower  50 . Even more thermal and pressure gradients are created once air  138  leaves housing  25 .  
         [0044]    The multiple gradients attract mosquitoes  22 . As attracted mosquitoes  22  enter housing  25  through guard  70 , they alight upon grid  60  where they are subsequently disintegrated (i.e. Mosquito  23 ). Since system  20  attracts mosquitoes without ultraviolet light, beneficial insects and other insects are not attracted to system  20 . In other words, since system  20  uses the infrared spectrum to attract target insects such as mosquitoes, the system  20  does not attract large numbers of non-target insects.  
         [0045]    Experience dictates that the air  138  passing guard  70  should approximate 100 degrees Fahrenheit. In other words, on windy or cold days, the thermostat  126  should run heater  122  longer than warm, hot days.  
         [0046]    [0046]FIG. 10 shows a second preferred embodiment of the invention. According to this embodiment, apparatus  200  provides a heated air space  202  between outer wall  202   a  and inner wall  202   b  of the main body of the apparatus  200 . Space  202  may reheated by any appropriate mechanism such as a heating tube, resistive conductors, or equivalent heat producing mechanisms, such as heater  122  as shown in FIGS. 7 and 8. The heated space  202  creates a heat blanket or gradient around the periphery of the apparatus, which attracts mosquitoes to the outer surface  202   a . A fan  204  driven by a motor  206  causes the air flow in the direction of arrows  220 , from the vicinity of outer surface  202   a  and down into interior chamber  221  of the apparatus  200  thorough an opening between a canopy  210  and the top of the main body of the apparatus  200 .  
         [0047]    An electrocution grid  212  is provided in the interior chamber  221 . Mosquitoes are attracted to the surface  202   a  by the surrounding heat and are sucked into the apparatus by air currents  220 , where they are forced down onto the grid  212  and electrocuted. Mosquito remains then fall into a removable trap  214 , which is removed from the bottom of the apparatus  200  for disposal. A wire mesh  216  covers the bottom of the apparatus to prevent access to the interior.  
         [0048]    The embodiment of FIG. 10 provides a measure of safety by placing the electrocution grid inside the body of the apparatus, precluding inadvertent contact by humans. The electrocution grid is mounted horizontally so that mosquito remains fall into trap  24  through the force of gravity, eliminating the need to periodically clean the electrocution grid.  
         [0049]    [0049]FIG. 11 shows a motion pole  300  for use with a mosquito killing apparatus according to the embodiments of the invention, and in particular with the embodiment of FIG. 10. Motion pole  300  includes a vertical arm  302  for placement in the ground or mounting on a floor, and a horizontal arm  306 . Arm  306  contains a track in which an auger screw  308  is installed. Screw  308  is coupled to a motor  304  for rotating the screw  308 . A hook  310  is connected to the auger screw and is moved along the length of arm  306  as the screw is rotated by the motor. A pair of limit switches  312  are provided near the ends of arm  306  and function to reverse the direction of the motor when they are activated by coming into contact with hook  310 . A suitable attachment mechanism such as loop  218  is provided on the apparatus  200  for engagement with the hook  310 . Alternatively, hook  310  may be inserted into an eyelet provided in the top of the apparatus  200 .  
         [0050]    In operation, the apparatus  200  slowly transverses the path between the limit switches  312  on the horizontal arm  306 , simulating motion of a living animal, which provides an attractant to mosquitoes in the surrounding area.  
         [0051]    It is further understood that the foregoing description is of preferred embodiments of the present invention and that various changes and modifications can be made without departing from the spirit and scope thereof. For example, the power supply may be adapted to be battery powered for increased portability to remote areas. Additionally, solar panels may be added to the apparatus to provide solar power which could be stored in rechargeable batteries. The heating source may be implemented by a solar hear tube, which absorbs solar heat and releases the absorbed heat in a thermostatically regulated fashion to maintain a temperature simulating body temperature of living animals or humans. It is noted further that while various mosquito attractants have been disclosed in the present specification, it is to be understood that not all attractants need to be used together in the same apparatus, and that different attractants as described above may be used in areas where different species of mosquito are present.