This application is a Divisional application of U.S. patent application Ser. No. 09/741,487, filed Dec. 18, 2000, now U.S. Pat. No. 6,401,383. 
    
    
     TECHNICAL FIELD 
     This invention relates to an apparatus to attract and kill flies, specifically to a non-toxic, non-chemical electronic means for reducing the fly population in and around commercial facilities such as dairies, feed lots, poultry houses, and processing plants by applying a burst of high voltage oscillations to a set of or a grid of exposed parallel conductors. The flies are attracted to these exposed conductors by appealing to the flies natural instincts to breed an lay their eggs. The flies that contact the exposed conductors are killed and fall to the ground under the apparatus. 
     BACKGROUND-DESCRIPTION OF PRIOR ART 
     U.S. Pat. No. 5,325,624 issued to Richardson et al on Jul. 5,1994 discloses a non-toxic, non-chemical, non-polluting electronic apparatus to control the fly population within an animal or poultry enclosure which does not kill by electrocution or incineration but rather by destroying the nervous system of the fly with a short burst of high voltage oscillations that is applied to a set of parallel conductors. U.S. Pat. No. 5,979,107 issued to Richardson et al on Nov. 9, 1999 disclosed an improved means for obtaining and installing the parallel conductors that is also not limited to straight runs but can be installed in any pattern as long as the proper spacing between the conductors is maintained. Both of the above apparatus relied on the natural instincts of some species of flies to roost and are limited to permanent indoor applications. 
     Experience resulting from the widespread use of the above inventions has shown the need for an apparatus that will attract and kill blow flies, carrion flies, face flies, and other biting and pest flies as well as the common house flies. These other flies and biting insects are not attracted to a roosting site as are the common house flies and they generally populate outdoor areas rather than indoor facilities. 
     The electronic devices generally used as a means of eliminating insects near homes and gardens using blacklight or fluorescent lights as an attractant and a constant high voltage alternating current on the grid to kill the insects have been tried and proven to be ineffective for these applications. The insects that are of a concern to the commercial farmer and food processor are common house flies, blow flies, carrion flies, face flies, and other biting and pest flies. These flies are not attracted by the fluorescent or black lights used in the units that are intended primarily for mosquitoes and moths. 
     Devices called “fly traps” using carrion or rotting mash as an attractant are available for commercial use. Their general configuration is one where the fly is attracted through a funnel trap arrangement into a bucket to collect the flies. The bucket must be cleaned out periodically and therefore maintenance of the units is high and in heavy fly infestations these units are easily overwhelmed. 
     U.S. Pat. No. 5,369,909 issued to Murphy on Dec. 6, 1994 places a set of parallel conductors on an electric fence and uses the high voltage pulse from an electronic fence charger and a ground rod as the electrical return path. The experience gained from many tests has proven this to not be an effective fly killing device. The high voltage pulse from a fence charger does not contain sufficient energy to kill flies and the ground return is not reliable as a low resistance conductor. A typical electronic fence charger produces very narrow pulses (1-2 usec) with an amplitude of 6-10 KV peak and a pulse repetition rate of about one pulse per second. The output energy content of these fence controllers is determined by the size of the capacitor in which the energy is stored and the voltage across the capacitor. The relationship is expressed mathematically as E=½ C(V×V) where E=energy in joules. A typical electronic fence charger will have a potential pulsed energy output of 0.5 to 10 joules. A standard electronic fence charger with the highest output energy will not kill flies on a conducting wire grid as defined herein. It tends to have the same effect on flies as it does on a cow or a horse, that is, the shock repels the animal and trains it to stay away from the device. 
     Another problem found in the attempts to use a standard electronic fence charger to supply the killing voltage to the grid network was the pulse repetition rate of about 1 per second does not allow sufficient time for the fly to land on the grid network or surrounding surfaces and approach the conducting grid. The repetition rate must be one every 2 to 4 seconds. Two seconds allows time for the flies to land and 4 seconds does not allow sufficient time for them to get to the holes to the attractant. 
     Extensive testing has found that a pulse width of 20 milliseconds or greater is required to supply sufficient energy to kill flies. As the pulse width is decreased below 20 milliseconds fewer and fewer flies will be killed and more just repelled. Greater than 80 milliseconds contains sufficient energy to cause ignition of some materials. 
     A typical electronic fence charger outputs a pulse of approximately 1 microsecond. To increase this pulse width from 1 microsecond to the required 20 milliseconds would require an unreasonably large capacitor. This capacitor would have to be in excess of 200,000 microfarads with an operating voltage capability of at least 600 VDC and would have to store over 10 to the 13th power (obviously impossible) joules. 
     The invention disclosed herein supplies a voltage burst to the grid network that is 8000 volts peak-to-peak with a duration of 60 milliseconds and a burst repetition rate of one burst every 2½ seconds. This is a burst of 8000 V peak-to-peak oscillations and not an 8000 Volt peak pulse of energy as is outputted by electric fence chargers. This burst provides the maximum killing energy to effectively kill the flies but remains narrow enough and infrequent enough to be safe considering fire hazards as well as safety to humans and animals. 
     The use of a high impedance output transformer limits the output current and thus gives added safety to humans and animals but provides sufficient power to kill flies that contact the parallel conductors of the grid. 
     OBJECT AND ADVANTAGES 
     It is recognized by all concerned with the production of livestock or poultry and operators of dairies and food processing plants that control of the fly population is necessary to maintain animal health, keep the premises sanitary, and reduce complaints from workers and neighbors. The animals in these locations attract a great many flies that can lead to health related problems for the animals as well as complaints from surrounding residents. Dairies often move the livestock to different pastures at varying periods which means that the fly control apparatus must necessarily be moved from time to time to remain in proximity to the livestock and to maintain its effectiveness to control the fly population. Food processing plants have similar fly control problems and the chemicals available for control at these locations is very limited, expensive, and the use of them is continuously under attack by environmental and governmental groups. Whereas, the concepts disclosed in U.S. Pat. Nos. 5,325,624 and 5,979,107 provides only an attractive roosting site and kills the flies that land on the roosting means, the basic objective of this invention is to provide the most efficient attractant for the given environment and nature of the pests and provide an electronic means to kill the attracted flies and control their population whether indoors or outdoors. 
     The referenced patents use extremely long runs of highly conductive parallel wires as a roosting means (up to several thousand feet) hung throughout the livestock enclosure. The roosting means must be moisture resistant but need not be weather proof as they are always installed inside the livestock enclosure. An object of this invention is to disclose a new relocatable killing grid, hereafter referred to as the “Fly Tower”, that contains an active attractant that represents a perfect breeding/laying means to attract all species of flies and kills the flies with a controlled burst of high voltage oscillations from an electronic control unit thus killing more flies and a broader range of fly species. 
     Another objective of this invention is to provide a simple non-toxic, non-chemical, effective, inexpensive fly population control apparatus that requires very little maintenance and can be effectively and safely used indoors or outdoors in all weather conditions. 
     Another objective is to provide a fly control apparatus that can be easily and quickly moved from one location to another to “follow the herd” and thus be easily relocated to the problem areas. 
     Another objective is to provide an apparatus wherein several of the attracting and killing means can be operated from one electronic device. 
     Another objective is to provide means of attracting the flies that not only attracts and kills the common house fly but also will attract and kill blow flies, carrion flies, face flies, and other biting and pest flies. 
     Another objective of this invention is to reduce the labor necessary to install the fly killing system and also to reduce maintenance cost associated with previously disclosed systems. 
     Another objective of this invention is to disclose an inexpensive, effective electronic control unit that can be powered from a standard 12 volt battery for use in remote locations where 115 VAC power is not available. 
     Further objectives and advantages of this invention will become apparent from a consideration of the drawings and ensuing description. 
    
    
     DRAWING FIGURES 
     FIG. 1 shows a typical Fly Tower installation 
     FIG. 2 is a detail drawing of the Fly Tower enclosure 
     FIG. 3 is a detail drawing of the killing grid used in the Fly Tower 
     FIG. 4 is a block diagram illustrating the first embodiment of he electronic control unit of this invention 
     FIG.5 is a schematic diagram of the electronic control unit 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The Fly Pop&#39;R system as described in U.S. Pat. Nos. 5,325,624 and 5,979,107 was designed to operate with long conductor runs (up to 2500 feet) of killing cables or cord installed inside animal or poultry buildings. The killing cables or cord provides a roosting site and therefore will attract large quantities of flies that are inside the building. However, there are common house flies and also other species of flies present outside of these buildings as well as in and around feed lots, dairies, slaughter houses, food processing plants, etc. 
     The improvements to U.S. Pat. Nos. 5,325,624 and 5,979,107 disclosed in application Ser. No. 09/741,487 now U.S. Pat. No. 6,401,383 provide a non-toxic, non-chemical, inexpensive apparatus for killing roosting flies both indoors and outdoors. However, there are other species of pest flies that do not share the roosting instinct with house flies, face flies etc. 
     Many species such as carrion flies, fannia flies, horn flies, horse flies, and other pest flies, while not having roosting instincts, all share a very strong reproductive instinct. They are attracted by rotting animal and vegetable matter, not only as food, but as an egg laying site. It is therefore obvious that to control all species of flies, a way to mimic an odor that will appeal to the reproductive or feeding instinct and eliminate the fly once it was attracted is a desirable goal. The present preferred embodiment of the attracting and killing apparatus is disclosed herein. This apparatus will be referred to as the Fly Tower  200  and can be used as an extension to the improved Fly Pop&#39;R system or as an independent system. After reviewing the following disclosures, it will be readily apparent that the Fly Tower  200 , as an extension to the improved Fly Pop&#39;R system, provides a non-toxic, non-chemical, inexpensive system for controlling the population of all species of flies both indoors and outdoors. 
     The present preferred embodiment for the Fly Tower  200  is shown in FIG.  1  and FIG.  2 . It consists of a weather proof enclosure  201  that houses a bait chamber  250  and a pair of killing grids  215  and  216 . This enclosure  201  is mounted about 4 feet above ground level on a mounting rod  213  that is driven into the ground for stability. The mounting rod  213  is metal such as a 1″ galvanized pipe to prevent small animals that might be attracted by the odor from the bait chamber  250  from climbing to the enclosure  201 . The enclosure  201  is easily removed from the mounting rod  213  by removing a retaining bolt  240  that securely fastens a mounting bracket  241  to the mounting rod  213 . 
     The present preferred embodiment for the Fly Tower  200  enclosure  201  is shown in FIG.  2 . The enclosure  201  consists of a top  202 , ends  203  and  204 , and back plates  205  and  206  that hold the killing grids  215  and  216 , all made of ¼″ white polyethylene. The top  202  extends beyond the sides to add the weatherproof aspects of the enclosure  201 . The two end panels  203  and  204  are removable with stainless steel screws  207 ,  208 ,  209  to allow access to the bait chamber  250 . Two back plates  205  and  206  support the killing grids  215  and  216  and have strategic holes  230  to allow the bait attractant odor to escape the enclosure  201  as shpwn in FIG.  3 . 
     A block of wolmanized lumber  210  is used as a base plate and it makes up the floor of the enclosure  201 . This gives a solid foundation on which to attach the mounting bracket  241 , the ends  203  and  204  and provides a location for the bait chamber  250  to sit. 
     Two upper frame supports  211  and  212  are attached to the top  202  and provide support for the killing grids  215  and  216 . These are also made from wolmanized lumber to resist the weather. 
     The details of a killing grid assembly  219  is shown in FIG.  3 . The killing grid assembly  219  consists of a back plate  205  and  206  on which is mounted two groups of ⅛″ stainless steel rods spaced 9/32″ apart. Each group  221  and  222  is held securely to the back plate  205  by three polypropylene threaded studs  218  and a threaded brass stud  225  and  226 . Back plates  205  and  206  are identical. 
     The back plate  205  is constructed of ¼″ white polyethylene and has several strategically located holes  230  drilled in it to allow the odor from the attractant in the bait chamber  250  to escape the enclosure  201 . 
     The two groups of rods  221  and  222  are electrically isolated from each other as each group  221  and  222  will be at different electrical potentials during operation. The groups of rods  221  at  222  are maintained at a separation of 9/32″ at all points. 
     The distance between the face of the back plate  205  and the bottom edge of the rods  221  and  222  that make up the killing grid  215  is maintained at ½″. This spacing is sufficient to allow the dead flies to drop out to the ground but not enough space for the flies to get to the odor holes  230  without contacting the killing grid  215 . 
     The threaded brass studs  225  and  226  are attached to the high voltage wires  103  and  104  on the backside of the back plates  205  and  206 . 
     Another embodiment is a single group  221  or  222  of rods mounted on but electrically isolated from a back plate  205  or  206  that is made from a conducting material such as stainless steel. The grid  221  or  222  and the conducting back plate  205  or  206  are connected to the high voltage wires  103  and  104 . This configuration is not as efficient as the preferred embodiment in that the dead flies can more easily become lodged between the grid  221  or  222  and the conducting back plate thus requiring more maintenance. 
     The present preferred attractant consists of one quart 50/50 mixture of cornmeal and meat scrap meal. Both of these meals are dry powder which makes them light and easy to handle and ship. Neither of these meals has a strong or objectionable odor in the dry state. To activate them, they are placed in a plastic container and mixed with enough water to make a slurry. The container is then placed in the bait chamber  250  of the Fly Tower  200  enclosure  201 . Within a short time the odor will be very attractive to all species of flies, but noticeable to humans only when they are close to the Fly Tower  200  installation. Once mixed with water and allowed to react, even if the mixture dries out, the odor will remain strong enough to attract flies. 
     The Fly Tower  200  is weatherproof, easy to install and use, and needs no cleaning. Once purchased it will require only minimal expenses for electricity and a yearly replacement of the attractant. Several Fly Towers  200  can be operated from one control unit  300  and the Fly Towers  200  may be moved at any time to accommodate rotational grazing, or changing fly problems. They can share an electronic control unit  200  with an outdoor or indoor installation of killing cables  101  and  102  as previously defined. 
     The Fly Tower  200  attractant is strong enough to lure flies away from cattle, poultry, and other livestock, and bring them to the self cleaning, electronic killing grid from long distances. 
     The Fly Tower  200  is very different and much safer than an electric fence. It is safer because the rods  221  and  222  of the killing grids  215  and  216  of the Fly Tower  200  are only 9/32″ apart. Anyone touching the grid will only have the electricity pass through a finger tip for 9/32″. It will not pass through the wold body to reference ground like an electric fence. 
     The Fly Tower  200  electronic control unit is very different from fence charger electronics. Even the most modern, powerful fence chargers will not kill a fly. If a fence charger is used in place of the Fly Tower  200  power unit, the capacitor discharge of the fence charger does not generate enough energy to damage the fly&#39;s nervous system. There is only a snap, and the fly flies away. The Fly Tower&#39;s  200  longer duration oscillatory power burst is needed to kill flies. 
     If 115 VAC power is available, an electronic control unit as disclosed in U.S. Pat. No. 5,325,624 is usable if modified to meet the requirements for operating the Fly Tower  200  as disclosed herein. The modifications are to increase the burst time from 20 milliseconds to 60 milliseconds and the burst repetition rate from one every 2 seconds to one every 2½ seconds. The high voltage oscillations must remain at 8000 V peak-to-peak. 
     However, because of the potentially remote locations for mounting the Fly Tower  200  the need for a battery powered electronic control unit is obvious. 
     FIG. 4 is a block diagram illustrating a first embodiment of an improved electronic control unit  300  and FIG. 5 is a schematic of the preferred embodiment for this unit. This unit uses a commercially available DC to AC inverter  302  to produce the 115 VAC necessary to drive a high voltage transformer  307 . This power inverter  302  is available from Waga Tech is Item #39393. It produces 115 VAC # 60 Hz and an output power of 400 watts peak with a 10-15 VDC input as shown from a 12 volt battery  301 . 
     A 12 VDC regulator  303  consists of a blocking diode  331  and limiting resistor  332  that limit the direction and amount of current into a filter capacitor  333 , zener diode  334 , and oscillator  304 . A regulator  303  limits the voltage to the oscillator  304  to a maximum of 12 VDC. 
     Oscillator  304  generates the timing to turn on a triac  306  as required to produce the high voltage burst from transformer  307 . 
     Operator isolator  305  isolates the lower voltage DC circuitry from the triac  306  which operates at 115 VAC. 
     Oscillator  304  is of standard NE555 design  341  and produces an oscillating square wave output with an on time (high at pin  3 ) of 60 milliseconds and an OFF time (low at pin  3 ) of 2½ seconds. 
     Resistors  335  and  336  along with diode  337  and capacitor  338  are selected to produce this desired output. Typical values are resistor 335=51 K, resistor 336=2.4 meg., and capacitor 338=2.2 uf. 
     Optical isolator  305  is a standard device such as a Motorola MOC  3010  that has a triac driver output. Resistor  337  (typically =680 ohms) limits the current to the input of the optical isolator  305 . Resistor  340  (typically=1 K) limits the current through the optical isolator  305  output and thus the gate current to the triac  306 . Triac  306  is a standard commercial device such as a Motorola  2 N 6239 . 
     A primary  351  of high voltage transformer  307  is supplied current from the output of the DC to AC Inverter  302  and is switched on and off by the action of a triac  306  (under control of an oscillator  304 ) which is in series with the primary  351 . When current is flowing from the 115 VAC output of the DC to AC inverter  302  to the primary  351  of the high voltage transformer  307 , the high impedance secondary  352  of this transformer  307  is producing an 8000 V peak-to-peak, 60 Hz oscillation. This high voltage is present for 60 milliseconds and occurs every 2½ seconds. This is the voltage that is present across the killing cables  101  and  102  and the Fly Tower  200  grid networks  215  and  216  that kills the flies that are present. 
     A pair of high voltage wires  103  and  104  with an insulation sufficient to withstand these high voltages is used to connect the electronic control unit  300  with the Fly Tower grid networks  205  and  216 . 
     OPERATION 
     FIG. 1 shows a typical installation of the Fly Tower  200 . 
     A 1″ galvanized pipe is driven into the ground to form the mounting rod  213 . The Fly Tower  200  enclosure  201  is then attachrd and securely held by retaining bolt  240  and mounting bracket  241 . 
     High voltage wires  103  and  104  are attached to the threaded brass studs  225  and  226  that are on the backside of the back plates  205  and  206 . This connects the high voltage bursts of oscillations generated by the electronic control unit  300  to the killing grids  215  and  216 . 
     The high voltage bursts of oscillations may be connected electrically in parallel via high voltage wires  103  and  104  to several Fly Tower  200  installations. They may also be electrically connected in parallel to several runs of killing cables  101  and  102 . 
     A 50/50 mixture of cornmeal and meat scrap meal is mixed with enough water to make a slurry. An open plastic container of this slurry is then placed in the bait chamber  250  of the Fly Tower enclosure  201 . Within a short time the odor from the slurry will become very attractive to all species of flies both as food and a reproduction location. 
     When the electronic control unit  300  is activated, the high voltage burst of oscillations (8,000 V peak-to-peak, 3½ to 4½ cycles of 50/60 Hz, that occurs once every 2½ seconds) is present across the killing grids  215  and  216  of the Fly Tower  200 . 
     The combination of a passive roosting site and an active attractant produced by the Fly Tower  200 , will draw large quantities of flies that are then killed by the high voltage burst of oscillations produced by the electronic control unit  300 . 
     SUMMARY OF THE INVENTION 
     According to this invention in one form the apparatus consists of an electronic control unit  300  that provides a controlled burst of high voltage oscillations to a grid of parallel conductors that are in proximity to an active attractant that appeals to the feeding and reproductive instincts of all species of flies. 
     Thus a device is provided for controlling fly populations while at the same time providing a device which is safe for use around humans, safe for use in nearly any environment and which is inexpensive to operate and which requires very low maintenance. 
     Accordingly, the reader can see that the apparatus of this invention can be used to control the population of flies outside an animal or poultry shelter. In addition, the reader can see that the techniques and apparatus described in this disclosure are not only unique but also safe, effective and inexpensive and also represent a clearly marketable product. 
     Although the descriptions herein contain many specifications, these should not be construed as limiting the scope of the invention but merely producing illustrations of the presently preferred embodiments of this invention. It is to be understood that the invention may be modified in many ways within the scope of the appended claims. In particular, it is to be understood that the invention is not limited to the specific embodiment wire configuration, killing grid configuration, electronic circuitry, pulse width and timing, or to the numerical values employed in describing this invention. Furthermore, many other types of components and materials may be employed in practicing the invention in place of those which have been specifically described. 
     REFERENCE DESIGNATIONS 
       103  HV wire 
       104  HV wire 
       200  Fly tower 
       201  Enclosure 
       202  Top 
       203  End panel 
       204  End panel 
       205  Back plate for grids 
       206  Back plate for grids 
       207  Stainless Steel Screw 
       208  Stainless Steel Screw 
       209  Stainless Steel Screw 
       210  Wolmanized base plate 
       211  Upper frame support 
       212  Upper frame support 
       213  Mounting rod 
       215  Killing grid 
       216  Killing grid 
       218  Threaded poly studs 
       219  Killing grid assembly 
       220  Killing grid assembly 
       221  Group of stainless steel rods 
       222  Group of stainless steel rods 
       225  Brass stud 
       226  Brass stud 
       230  Holes in  205  and  206   
       240  Retaining bolt 
       241  Mounting bracket 
       250  Bait chamber 
       300  Electronic Control Unit 
       301  12 V battery 
       302  DC/AC power inverter 
       303  12 VDC regulator 
       304  Oscillator 
       305  Optical isolator 
       306  Triac switch 
       307  HV transformer 
       331  Blocking diode 
       332  Limiting resistor 
       333  Filter capacitor 
       334  Zener diode 
       335  Resistor 
       336  Resistor 
       337  Diode 
       338  Capacitor 
       339  Capacitor 
       340  Resistor 
       341  NE555 
       351  HV transformer-primary 
       352  HV transformer-secondary
An improved non-toxic, non-chemical, non-polluting, inexpensive electronic apparatus to control the population of many species of flies both indoors and outdoors around poultry and animal enclosures and food processing facilities which attracts and then kills the flies with a burst of high voltage oscillations that is applied to an exposed grid network of closely spaced parallel conductors.