Abstract:
Disclosed are heatable enclosures useful in treating materials for eradication of pests. Specifically, a heating layer which can be fitted or retrofitted into a numerous and wide variety of containers and enclosures, such as suitcases, boxes, trucks and trailers, which are operable to heat the enclosed space of the container to treat heatable materials over a period of time to eradicate pests. Heating films can be utilized that are inexpensive and lightweight.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present patent application is based upon and claims the benefit of U.S. Provisional Patent Application Ser. No. 61/403,411, filed on Sep. 14, 2010, by Michael David Lindsey, entitled “Heatable Enclosure for Pest Eradication,” which is hereby specifically incorporated herein by reference for all that it discloses and teaches. 
    
    
     BACKGROUND 
     Pest and insect damage to materials, fabrics, and garments is a growing problem. As a non-limiting example, insect damage to textiles in the United States is estimated at $200 million annually. Fabric and garment insect infestations are making a comeback because most of the insecticides formerly used to control insects and pests, such as dieldrin and dichlorodiphenyltrichloroethane (“DDT”), have been banned. 
     Accordingly, as people travel, or as containers are shipped from location to location, there is a growing incidence of pest or insect infestation of garments transported in luggage and materials shipped in containers. For example, bed bugs may be found in many hotels, motels, homes, or other accommodations, even in highly sanitary conditions. During the day, nocturnal insects, such as bedbugs, disappear in crevices associated with mattresses, box springs, sheets, upholstery, garments, clothes, pillows, towels, or the like. Even when these materials are examined, it is common for these insects, or the eggs of these insects, to go undetected and packed with garments and transported in luggage. 
     SUMMARY OF THE INVENTION 
     An embodiment of the present invention may therefore comprise a system for killing pests on heatable materials comprising: an enclosure that is adapted to receive the heatable materials, the enclosure having an exterior surface and an interior surface that surrounds an interior space of the enclosure; a heating film that generates infrared radiation comprising a resistive material that is disposed on a substrate, the heating film disposed in the interior space of the enclosure; an insulating layer disposed between the heating film and the interior surface of the enclosure; and a control device, that is operatively coupled to the heating film, that controls current flowing through the heating film so that the infrared radiation penetrates and heats the heatable materials disposed in the enclosure to a sufficiently high temperature, for a sufficiently long period, to kill the pests. 
     An embodiment of the present invention may further comprise a method of killing pests on heat treatable materials comprising: providing an enclosure that is adapted to receive the heatable materials, the enclosure having an exterior surface and an interior surface that surrounds an interior space of the enclosure; providing a heating film that generates infrared radiation comprising a resistive material that is disposed on a substrate, the heating film disposed in the interior space of the enclosure; providing an insulating layer disposed between the heating film and the interior surface of the enclosure; and providing a control device that is operatively coupled to the heating film, that controls current flowing through the heating film so that the infrared radiation penetrates and heats the heatable materials disposed in the enclosure to a sufficiently high temperature for a sufficiently long period to kill the pests. 
     An embodiment of the present invention may further comprise a system for killing pests on heatable materials comprising: an enclosure that is adapted to receive the heatable materials, the enclosure having an exterior surface and an interior surface that surrounds an interior space of the enclosure; a resistive wire heating layer that generates heat by Joule heating comprising a resistive material that is disposed on a substrate, the heating layer disposed in the interior space on multiple surfaces of the enclosure; an insulating layer disposed between the heating film and the interior surface of the enclosure; and a control device, that is operatively coupled to the heating layer, that controls current flowing through the heating layer so that the infrared radiation penetrates and heats the heatable materials disposed in the enclosure to a sufficiently high temperature, for a sufficiently long period, to kill the pests. 
     An embodiment of the present invention may further comprise a method of killing pests on heat treatable materials comprising: providing an enclosure that is adapted to receive the heatable materials, the enclosure having an exterior surface and an interior surface that surrounds an interior space of the enclosure; providing a resistive wire heating layer that generates heat by Joule heating comprising a resistive material that is disposed on a substrate, the heating film disposed in the interior space on multiple surfaces of the enclosure; providing an insulating layer disposed between the heating layer and the interior surface of the enclosure; and providing a control device that is operatively coupled to the heating layer, that controls current flowing through the heating layer so that the heat penetrates and heats the heatable materials disposed in the enclosure to a sufficiently high temperature for a sufficiently long period to kill the pests. 
    
    
     
       A BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an illustration of an embodiment of a heatable enclosure for pest eradication. 
         FIG. 2  is an end view of the embodiment of the heatable enclosure of  FIG. 1 . 
         FIG. 3  is a left side view of the embodiment of the heatable enclosure of  FIG. 1 . 
         FIG. 4  is a top view of the embodiment of the heatable enclosure of  FIG. 1  having a releasably sealable access element in a closed condition. 
         FIG. 5  is a right side view of the embodiment of the heatable enclosure of  FIG. 1 . 
         FIG. 6  is a top view of the embodiment of the heatable enclosure of  FIG. 1  having a releasably sealable access element in an open condition. 
         FIG. 7  is an opposite end view of the embodiment of the heatable enclosure of  FIG. 1 . 
         FIG. 8  is a cross section of the embodiment of  FIG. 1 . 
         FIG. 9  is an isometric, enlarged view of the heatable enclosure user interface utilized in the embodiment of the heatable enclosure illustrated in  FIG. 1 . 
         FIG. 10  is a flow diagram of an embodiment of a method of using a heatable enclosure. 
         FIG. 11  is an exploded view of another embodiment of a heatable enclosure. 
         FIG. 12  is a side view of a truck that is outfitted to be a heated enclosure. 
         FIG. 13  is a back view of the truck of  FIG. 12  illustrating a heating film, protective layer and insulating layer that are utilized to convert the truck to a heated enclosure. 
         FIG. 14  is an exploded view of layers, which may comprise a portion of an enclosure. 
         FIG. 15  is an exposed view of layers, which may comprise a portion of another embodiment of an enclosure. 
         FIG. 16  is a top view of a heating element that uses resistive wires. 
         FIG. 17  is a graph of the response of a bi-metallic thermal switch. 
         FIG. 18  is a block diagram illustrating the structure and layout of an embodiment of a control system. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  is a perspective view of an embodiment of a suitcase enclosure  100  that can be heated to kill pests  112 . Heat-treatable materials, such as shirts, clothing and other items, can be placed in the main enclosure  104  of the suitcase enclosure  100  for heat treatment. Certain pests such as bedbugs may hide in clothing and other items that are transported by suitcases, or on the external surfaces of the suitcase. To ensure that the transported items, such as the heat treatable material  110 , do not contain pests such as bedbugs, the heat treatable material  110  is placed within the suitcase enclosure  100 , which heats the heat treatable material  110  to a temperature that kills the pests. The suitcase enclosure  100  includes a main enclosure  104  and a hinged lid  102  that attaches to the main enclosure  104  using matably latchable parts  106 . The surfaces of the main enclosure  104  and hinged lid  102  include heating layer  132  that heat the main enclosure  104  to specified temperature for a sufficient amount of time to kill the pests. Surface temperature sensor  120  senses the interior surface temperature of various surfaces within the suitcase enclosure  100 , including the hinged lid  102 . A power cord  122  is connected to the user interface  114  of the suitcase enclosure  100 . Power cord  122  is plugged into an external power source  124  to obtain power to heat the suitcase enclosure  100  using the heating layer  132 . User interface  114  is used to control the process of heating the suitcase enclosure  100 . A central temperature sensor  118  senses the temperature in a central portion of the main enclosure  104 . The central temperature sensor  118  can be placed in any desired location in the main enclosure  104  to detect temperatures within the suitcase enclosure  100  to ensure that a sufficiently high temperature is reached for a sufficiently long time to kill the pests. 
     For example, a user may wish to obtain central target temperatures ranging from approximately 120° F. to approximately 150° F. for a period of between 30 minutes and an hour for the purpose of killing pests, such as bedbugs, contained within the main enclosure  104 . To fulfill this requirement, simple programming controls can be entered by a user through the user interface  114 . The user interface  114  can be used to program the central target temperature, wall temperatures, and/or length of time that heat is applied to the suitcase enclosure  100 . It has been empirically determined that maintaining a temperature of 120 degrees for a period of one minute will kill bedbugs. However, extended heat treatment, such as disclosed above, will ensure that the required elevated temperatures are reached in all portions of the main enclosure  104  for a sufficient time to kill pests, such as bedbugs and their eggs. Further, when elevated temperatures are maintained for a period of time in the suitcase enclosure  100 , the heat permeates the structure of the suitcase enclosure  100 , so that the external surfaces of the suitcase enclosure  100  also become heated. As the external surfaces of the suitcase enclosure  100  become heated, the pests, including bedbugs, will egress from the outer surfaces and external features  126  of the suitcase enclosure  100  and eggs will be destroyed. In this manner, the pests  112  are exterminated in the inside and egress, or are exterminated on outer surfaces of the suitcase enclosure  100 . This process can be performed at a remote location from the user&#39;s home to prevent transportation of the pests to the user&#39;s home. For example, the user may activate the user interface  114  in a hotel room prior to leaving the hotel room, or in an airport or other remote location. Alternatively, the process can be performed at the user&#39;s home employing methods to contain the pests  112  to prevent egress into the home. The pests  112  are either killed or egress from the outside surfaces of the suitcase enclosure  100  prior to being transported back to the user&#39;s home. In that regard, the user interface  114  can be used to change both the duration time of the heating cycle and/or the temperature of the heating cycle within the suitcase enclosure  100 . During the heating cycle that is set by the user interface  114 , the hinged lid  102  is preferably secured to the main enclosure  104  using the matably latchable parts  106 . In this manner, the heating layer  132  can concentrate the heat within the interior portion of the main enclosure  104 . User interface  114  can provide a display that presents the interior temperature sensed by central temperature sensor  18 , surface temperatures sensed by surface temperature sensor  120 , and elapsed time. After the heat cycle has been performed, additional heat cycles can be employed if desired by the user. Further, heat treatable material  110  can be then removed from the suitcase enclosure  100 , and additional heat treatable material  110  can be placed in the suitcase enclosure  100  for treatment. 
       FIGS. 2-7  comprise various views of the suitcase enclosure  100 .  FIG. 2  is a top end view of the suitcase enclosure  100 . As shown in  FIG. 2 , the matably latchable parts  106  secure the hinged lid  102  to the main enclosure  104 . The matably latchable parts  106  may comprise a zipper, latches, snaps, seal or other means of mating the hinged lid  102  to main enclosure  104 .  FIGS. 3, 4, 5, 6 and 7  illustrate the different sides of the suitcase enclosure  100  and show external features  126 , such as seams, corner guards, or wheels. In that regard, the suitcase enclosure  100  may take any desired form or shape. In addition, the suitcase enclosure  100  may comprise other types of portable enclosures for treating heat treatable material  110 . In addition, suitcase enclosure  100  may be large enough to treat not only clothing, shoes and other types of personal items, but also items such as sheets and blankets, jackets and coats and other larger items. Clearly, one of the advantages of the suitcase enclosure  100  is that it is a portable, self-contained unit that is capable of connecting to a power source, such as a wall plug. In addition, the suitcase enclosure can be implemented to attach to other power sources, such as 12 or 24 volt outputs, such as through a cigarette lighter disposed on a vehicle, such as a car, truck, boat, etc. 
       FIG. 8  is a cross-sectional view of the suitcase enclosure  100  illustrating the various parts and construction of the suitcase enclosure  100 . As illustrated in  FIG. 8 , the suitcase enclosure  100  includes a hinged lid  102  and main enclosure  104  that form an internal space  108 . A movable central temperature sensor  118  is connected to a conductive tether  116 , which allows the central temperature sensor  118  to be placed in any desired location within the internal space  108  of the suitcase enclosure  100 . The main enclosure  104 , as well as the hinged lid  102 , include a plurality of layers  140 . Exterior surface layer  134  can be made from a canvas, plastic, leather, or other materials commonly used in the manufacturing of luggage. An insulating layer  136  is disposed on the external layer  134 . The insulating layer  136  assists in insulating the internal space  108  from the exterior surface layer  134  and traps the majority of the heat generated within the internal space  108  while transferring some amount of heat to the exterior surface layer  134 . A heating layer  132  is disposed over the insulating layer  136 . The heating layer  132  may comprise a heating film, such as heating film available from Korean Heating Company, Ltd., 1513-5 Dadae-Dong, Saha-Gu, Busan, South Korea; telephone number 82-51-264-2626; fax number 82-51-264-1626, Daewoo Electric Heating Company, Ltd., 188-1, Jangsa-Dong, Jongro-Gu, Seoul, South Korea; telephone number 82-2-2268-2011; fax number 82-2-6442-1963, or SEGGI CENTURY, Rm 908, Mugwang office building 1141-1, Jung-dong, Wonmi-gu, Bucheon-SI, Gyeonggi-do, South Korea; telephone number 82-32-3286699; fax number 82-32-3286464. As illustrated in  FIG. 8 , the heating layer  132  is disposed on all sides of the suitcase enclosure  100 . The application of heat from multiple surfaces allows the entire contents of the enclosure to be treated, to ensure that the pests  112  are killed and that pests on the outside of the suitcase enclosure  100  are either killed or egress from the surfaces of the suitcase enclosure  100 . 
     A heating film can be produced by screen printing an electrically resistive ink onto a substrate so that a plurality of narrow circuit lines are produced in the substrate. The resistive ink then generates radiated heat in the IR spectrum that is capable of penetrating much of the contents of enclosure  100 . In this manner, standard convection of air through the internal space  108  of suitcase enclosure  100  is not relied upon for distribution of heat. Infrared radiation absorbed by the heat treatable materials  110  in conjunction with thermal conduction ensures that the necessary temperatures are achieved throughout the internal space  108  in the main enclosure  104 . Of course, the materials used as resistive materials in the resistive ink of the heating film can be varied to create longer wave IR signals that are even more efficient at penetrating the heat treatable material  110 . 
     Alternatively, heating layer  132  can be constructed from a resistive wire heating element, which is more fully disclosed with respect to  FIG. 16 . A thermal conductive layer  138  is placed over the heating layer to increase the heat uniformity to the internal space  108 . A liner  139  may be placed over the thermal conductive layer  138 . The liner  139  is capable of transmitting heat generated from the thermal conductive layer  138  to the internal space  108 . 
     The heating film has additional advantages for application in the suitcase enclosure  100 . The heating film is mass-produced using inexpensive screen printing techniques. A very uniform heating profile can be generated using heating films as a result of easily instituted process controls that easily maintain consistent mixtures and uniform distribution of the resistive materials throughout the screen applied inks. Alternatively, non-uniform heating profiles may be designed into the screen printing process to address hot spots or cold spots in the application. Further, the heating films are extremely thin, i.e., on the order of 0.25 mm. As such, the heating films are lightweight and moderately pliable to shapes that will fit the suitcase enclosure  100 . The operating temperatures of the film are in the range of 70 to 80° C., which is ideally suited for killing pests  112 . The extremely light weight of the heat films adds virtually no detectable weight to the overall suitcase enclosure  100  and other portable devices in which the heating film can be used. Of course, the weight of a suitcase and other portable devices is an important factor to the marketing and sale of these devices. The addition of a very small and virtually undetectable amount of weight to a suitcase that has the ability to kill pests, as well as providing these solutions at only a moderately higher price, is an advantage in the sale and marketing of the suitcase enclosure  100 . The implementation of heat films in commercial products, in addition, does not face substantial impediments. Heat films are UL, CE and CSA approved. The construction of the films allows for easy modification for various power densities and voltages. Application techniques to the substrate allow for minimum gap between the heating elements in a simple and cost effective manner. Current films are available in 30, 50, 60, 80 and 100 cm widths that are easily modified to provide designs that fit exactly into any desired enclosure. 
     Alternatively, a heating film can be directly applied to a substrate layer that forms a portion of the main enclosure  104  and hinged lid  102  of the suitcase enclosure  100 . As indicated above, the heating film may be applied to a substrate layer, which may simply comprise the exterior surface layer  134 , using lithographic techniques, silk screening techniques or other techniques in which the resistive ink is applied directly to the substrate. In addition, a protective layer that has a reasonably high thermal conductivity can be applied directly over the applied resistive ink to provide a protective layer for the resistive ink. Spray-on plastics and other materials can be used to protect the resistive ink. For example, polyurethanes and polyureas can be used, as well as other protective films. Any thin film polymer, including polyethylene, polypropylene and similar polymers, can provide sufficient protection of the conductive/resistive ink layer. The polymer can have a thickness that is sufficient to conduct the infrared radiation, while still providing protection to the conductive/resistive ink. The polymer layer can be thin enough to allow conduction of the heat through the polymer layer and not providing a significant insulation to the heating element. 
       FIG. 8  also illustrates the suitcase controller  142  and the user interface  114 . The suitcase controller  142  may comprise a simple and inexpensive microprocessor controller that is easily programmable to operate with the user interface  114 . The user interface may comprise an inexpensive touch screen display, or a combination of LEDs and buttons, that can be utilized for input of user data. Both the user interface  114  and the suitcase controller  142  are inexpensive and can be readily programmed to perform the required control functions. 
       FIG. 9  is a perspective view of one embodiment of a user interface  114 . As shown in  FIG. 9 , the user interface is disposed in a location beneath the retractable handle  143 , which assists in protecting the user interface  114  from damage or accidental activation. In the embodiment illustrated in  FIG. 9 , an activation element  144 , in the form of a button, is utilized for the input of user data or to initiate a heat cycle. Bulkhead connector  146  provides a connector for connecting the external power source. Status indicator  148  may comprise any desired type of display for displaying operational data of the suitcase enclosure  100 . 
       FIG. 10  is a flow diagram illustrating the operational steps of suitcase controller  142 , as well as the workflow steps of a user of the suitcase enclosure  100 . At step  150 , the user closes a bag and inserts a power cord into the jack that is disposed in the bulkhead connector  146 . At step  152 , the suitcase controller  142  checks for system faults and determines whether the source of power is either 120 volts or 240 volts AC. Additionally, the controller can also test for 12 volt DC and 24 volt DC power inputs. If it is determined that faults exist, or there are other operational problems with the system, the user interface can provide an indication of the fault. In one example, the user interface may flash a red LED and maintain the heating element in an off condition. If it is determined at step  152  that no faults or system problems exist, the heating elements are turned on and the heating process begins. An indication that the bag is operating and other data may also be displayed. In one example, a yellow LED may be illuminated. At step  158 , the wall temperatures of the suitcase enclosure  100  are raised to a predetermined temperature level at a safe ramp rate. In the embodiment illustrated in  FIG. 10 , the wall temperatures are raised to a temperature of 150° F. At step  160 , the suitcase controller  142  initiates a timer for a pre-selected time period for operation of the heating element. Alternatively, a user may specify a time period and may specify a repeating interval for heating the suitcase enclosure  100 . In addition, the suitcase controller  142  monitors the temperatures from the central temperature sensor  118  and the surface temperature sensor  120 . The suitcase controller  142  may turn the heating element on and off to maintain the desired temperature, for example, 150° F., during the heating interval. Once the heating interval is completed, the user interface  114  may indicate a successful heating interval process to the user. In one embodiment, a green light may be illuminated by the suitcase controller  142  in the user interface  114 . If the heating interval is interrupted because a problem exists, such as the central temperature sensor  118  or the surface temperature sensor  120  detects overheating, the heating element is switched off and the failure of the heating interval is indicated on the user interface  114 . In the example of  FIG. 10 , a red LED is illuminated. 
       FIG. 11  illustrates another embodiment of an enclosure, which comprises a box  200 . The box  200  comprises an exterior carton  218  that has a bulkhead receptacle  220  that is adapted to receive the power cord  212 . The power cord  212  can plug into the power source  214  to provide power to the box  200 . The insulating floor  208  and insulating walls  206  are placed in the internal space  216  of the exterior carton  218 . A heating film  202 , that is formed to fit inside the insulating walls  206 , is placed on the interior surface of insulating walls  206 . An insulating lid  204  is then placed on top of the box-shaped heating film  202 . Closing flaps  210  can be closed upon activation of the power cord  212 . The box  200  of  FIG. 11  is a simpler design and less expensive design than the suitcase enclosure  100  of  FIG. 1 . Power cord  212  can simply be plugged into a power source  214  for a set period of time, which eliminates the need for a controller. Further, a user interface is not required with the box  200 , but rather, the user simply keeps the power cord  212  plugged into the power source  214  and bulkhead receptacle  220  for a given period of time, such as 60 to 480 minutes. Bi-metallic switches can be used to control the current and temperature in the manner described with respect to  FIG. 16 . Box  200  provides a simple and cost effective manner of creating an enclosure to kill pests and can be easily constructed in an inexpensive manner. Again, the heating film  202  is disposed on multiple sides of the box  200  to ensure that heat is being applied from multiple surfaces, to ensure that the pests are killed or egress from the outer surfaces of the box  200 . 
       FIG. 12  is a side view of a truck/trailer  300  that includes an enclosure  310  that forms part of the truck/trailer  300 . A user interface  308  is provided on an outside surface of the enclosure  310 . 
       FIG. 13  is a rear view of the truck/trailer  300  showing the door  312  in an open position. A rear view in  FIG. 13  is a partial cutaway view showing portions of the protective layer  306  that covers the heating film  302 . The heating film  302  is placed on the interior walls of the truck/trailer  300  and on a floor portion of the truck/trailer  300 . An insulating layer  304  is shown in a cut-away portion of the sidewalls of the truck/trailer  300 . The insulating layer  304  may comprise any desired type of insulating material that can be placed in the walls of the truck/trailer  300 . Insulating layer  304  may be attached directly to the inside surface of the walls of the truck/trailer  300  or may constitute foam insulation that is injected into the walls of the truck/trailer  300 . The heating film  302  can be formed in large sheets that are constructed to fit on the walls and the truck bed of truck/trailer  300 . Each of the sections of the heating film  302  can then be wired to the user interface  308 . The protective layer  306  may comprise a spray-on protective coating, such as used in truck bed liners. The protective layer  306  may be a homogeneous protective surface that is applied directly to the heating film  302  to provide a durable working surface to transport items for heat treatment. Various polymers can be used for the protective layer that can be sprayed on or directly applied to the heating film  302 . These polymers may comprise polyurethanes, polyureas, pure polyureas and similar materials that have durable characteristics between −50° F. and 200° F. Coatings may include Rhino Extreme 21-55 available from Rhino Linings Corp., 9151 Rehco Road, San Diego, Calif. 92121. Other protective coatings can be used, such as Line-X Excess-350 available from Line-X Protective Coatings, 6 Hutton Center Drive, Suite 500, Santa Ana, Calif. 92707. Both of these protective coatings comprise spray-on elastomers that are easily applied over the heating film  302 . Although  FIGS. 12 and 13  illustrate a truck/trailer  300  having an enclosure  310 , the identical process can also be used with stand-alone trailers. 
     Since bedbugs can be easily spread in furniture and other household and office items, the use of a truck or a trailer to kill pests, such as bedbugs, is extremely beneficial. For example, if bedbugs have infested furniture, including beds, couches, chairs, etc. in a home, the furniture can be removed and placed in the truck or trailer and subjected to one or more heat cycles within the trailer to kill the bedbugs. The furniture can then be placed back in the house with the assurance that the bedbugs have been exterminated. Further, if a user is moving from one location to another, the truck/trailer  300 , or a similarly constructed trailer, can be used to transport furniture that may be infected with bedbugs. One or more heating cycles may be used to ensure that bedbugs are exterminated from the furniture and other household items during the transportation of the items to a new location. Further, new furniture that is being transported to a purchaser can also be treated to ensure that there has no been infestation of bedbugs or other pests. As further illustrated in  FIG. 13 , the heating film  302  is applied to multiple surfaces, including the floor surface of the truck/trailer  300 , to ensure that the contents of the truck/trailer  300  are fully exposed to heat applied by the heating film  302 . This ensures that pests are killed on the contents of the truck/trailer  300 . 
       FIG. 14  is an exploded view of a portion of an enclosure with a surface heater  401  that utilizes a heating film  410 . The enclosure can comprise any desired type of surface heater  401  that has a plurality of layers  400 . As illustrated in  FIG. 14 , the heating film  410  has a plurality of carbon ink channels  416  that pass the electrical current  438  from bus bar  414 . The heat conductive layer  412  is disposed over the heating film  410  to protect the heating film  410  from damage and increase the heat uniformity to the interior surface  442 . The heat conductive layer  412  can comprise any desired material that has at least a moderate degree of thermal conductivity. As such, internal heat transfer  418  to the interior portion of the enclosure  402  occurs preferentially over the external heat transfer  420  to exterior space of the enclosure  404  of the enclosure, since insulation layer  408  is disposed between the heating film  410  and the exterior surface layer  406 . Exterior surface layer  406  can be used to support the insulation layer  408 . The exterior surface layer  406  can be selected from a numerous and wide variety of materials, such as those conventionally used in the external wall construction of luggage, including soft and hard luggage, such as metal, fabric, plastic, fiberglass or similar materials, to provide the exterior surface layer  406  with the proper rigidity necessary to create the enclosure. In addition, the exterior surface layer  406  may comprise materials that are conventionally used for the exterior wall construction of various containers as illustrated in  FIG. 11 , such as paperboard, cardboard, corrugated plastic, or similar materials commonly used by the packaging industry. The exterior surface layer  406  may be selected depending upon the intended use of the enclosure and the ability to properly enclose the insulation layer  408  and the heating film  410 . The insulation layer  408  may be disposed adjacent to, and mounted on, the exterior surface layer  406 . The insulation layer  408  may be selected from a numerous and wide variety of materials to provide a heat transfer barrier between the interior portion of the enclosure  402  and the exterior surface layer  406  surrounding enclosure. The internal heat transfer  418  to the internal portion of the enclosure  402 , versus the external heat transfer  420  to the external space of the enclosure  404 , is determined by the insulated value of the insulation layer  408 , the thermal conductivity of the heat conductive layer  412 , as well as the temperature difference between the interior portion of the enclosure  402  and the exterior space of the enclosure  404 . It is desirable to have external heat transfer  420  to the exterior surface layer  406  to cause pests, such as bedbugs, to egress from the exterior surface layer  406 . At the same time, it is desirable to have an insulation layer  408  that is sufficient to cause the internal heat transfer  418  to the interior portion of the enclosure  402 , so that a sufficient amount of heat is generated in the interior portion of the enclosure  402  to kill pests, such as bedbugs. Accordingly, the insulation layer  408  may comprise a plastic sheet material that is applied to the exterior surface layer  406 , such as foam board, closed or open cell foam, sheet or a spray foamed material, such as polyurethane foam, corrugated cardboard, fiber fill, such as bamboo fill, cotton fill, synthetic fiber fill, such as polyester fill, air filled sheets, or bubble material or similar materials. 
       FIG. 15  is another view of the construction of an enclosure with a surface heater  401  that utilizes resistive wire heating elements  422 .  FIG. 15  discloses a plurality of layers  400  that form an enclosure. An electrical current  438  is applied to resistive wire heating elements  422 , which generate heat by method of Joule heating. The resistive wire heating elements are supported by structural layer  440 . An insulation layer  408  is disposed between the structural layer  440  and the exterior surface  406 . The insulative qualities of the insulation layer  408  control the amount of internal heat transfer  418  to the interior portion of enclosure  402 , versus the amount of external heat transfer  420  to the exterior space of the enclosure  404 . A heat conductive layer  412  is placed over the resistive wire heating elements  422  to protect the resistive wire heating elements  422  from damage. Heat conductive layer  412  may comprise any desired heat conductive layer, including plastic materials and other suitable material. The resistive wire heating elements  422  can be made from resistive carbon fiber wire, electrically resistive ribbons, or other similar materials that are capable of generating heat in response to the flow of electrical current  438 . Electrically resistant wires and ribbons can be made from nickel, iron, nickel-chrome alloys, nickel-iron alloys, and similar materials. Wires and ribbons suitable for use with the invention include Balco alloy, Evanoham, Alloy R, Karma Mid-Ohm and similar products. Pelican Wire Co Inc, 3650 Shaw Boulevard, Naples, Fla. 34117-8408, telephone 1 (239) 597-8555; Kanthal 1 Commerce Blvd, Palm Coast, Fla. 32164; Telephone: +1 (386) 445 20 00; Fax: +1 (386) 446 22 44 
       FIG. 16  is an illustration of a surface heater that uses resistive wire heating elements  422 .  FIG. 16  is one embodiment illustrating the manner in which a resistive wire heating layer can be constructed to fit within conventional containers, enclosures, luggage, suitcases, garment bags, briefcases, duffle bags, backpacks, or the like. As shown in  FIG. 16 , the sidewall section  430  can be disposed along the sidewall of a container, such as a box. Floor section  426  can be disposed along a lower portion, while the lid section  428  can be disposed on an upper portion, of a container. Structural layer  440  may comprise an insulating layer, a thermal conductive layer, or a combination of the two. As illustrated in  FIG. 16 , one single structure, in the form of a heating shell  444 , can be used to surround the interior or exterior sides of a heating enclosure in one simple and easy to implement device. The specific geometry of the heating shell  444 , illustrated in  FIG. 16 , can be modified to produce various three-dimensional shapes when folded. Box shapes, rectangular shapes, cylindrical shapes, frusto-conical shapes, pyramid shapes, and other desired shapes can be formed depending upon the particular implementation. 
       FIG. 16  also illustrates a pair of thermal switch  432  devices that function to control the temperature of the heating layer illustrated in  FIG. 16 . The thermal switch  432  may take the form of a bimetallic switch that controls the flow of current based upon the output temperature of the heating layer illustrated in  FIG. 16 . In this manner, the thermal switch  432  is capable of controlling the application of current from power cord  434  to the resistive wire heating elements  422 . 
       FIG. 17  is a plot of the response of a bimetallic thermal switch  436  based on temperature over a period of time. As shown in  FIG. 17 , the bimetallic thermal switch is capable of maintaining the heating element at a temperature between approximately 140° F. and 160° F. Installation of the bimetallic switches in the circuit of the heating element illustrated in  FIG. 16  allows the heating element to automatically maintain a predetermined temperature between approximately 140° F. and 160° F. Bimetallic switches are available from Cantherm, 8415 Mountain Sight Avenue, Montreal (Quebec), H4P 2B8, Canada. Typical switches that can be used include Part No. F20A07005ACFA06E, which switches at 70° C. Part No. C5705025Y is a bimetallic thermal switch that switches at 50° C. 
       FIG. 18  is a schematic block diagram of an embodiment of a control system  500  that is suitable for use with the present invention. As illustrated in  FIG. 18 , the control system  500  includes AC power cord  502 , control board  526 , heater zone  524 , user interface  520 , and remote sensors  522 . The AC power cord  502  can be connected to a power source to supply power to a bulkhead connector  504 . Bulkhead connector  504  may comprise a male prong socket for the AC power cord  502 . Power from the bulkhead connector is supplied to an AC to DC converter  506 , which converts an AC signal to a DC voltage. Power sources in some countries operate on 220-240 volts, rather than US and Canada which operate at 120 volts AC. In that regard, AC line monitor  508  detects the input voltage and generates a signal that is supplied to the controller  510 , indicating the voltage range to the input signal from the AC to DC converter  506 . Controller  510  receives user inputs from user interface  520 . User inputs may include control signals to activate the heating system, duration of the heating time, desired temperatures, and other input information. User interface  520  also receives data from the controller  510  that is displayed on the user interface  520  indicating the operation of the control system  500 . Controller  510  includes analog to digital circuits and logic circuits for carrying out the logical operations of the control system  500 . Driver circuit  512  is controlled by the controller  510  to supply current to the heater load  516 . Driver circuit  512  may use a triac to control the current applied to the heater load  516 . Driver circuit  512  is connected directly to the power supply from the bulkhead connector  504  to supply power directly to the heater load  516 , which is disposed in the heater zone  524 . A fault detection circuit  514  is connected to the heater load  516  to determine if there are any faults in the heater load  516 . If so, a signal is transmitted from the fault detection circuit  514  to the controller  510  to turn off the power supplied by the driver circuit  512 . Temperature sensors  518  provide data to the controller  510  for operation of control system  500 . In addition, remote sensors  522  provide additional information that assists the controller  510  in proper operation of the control system  500 . Temperature sensors  518  may comprise surface temperature sensors, such as surface temperature sensor  120 . Remote sensors  522  may comprise a central temperature sensor, such as central temperature sensor  118 , illustrated in  FIG. 1 . 
     Controller  510 , illustrated in  FIG. 18 , regulates the power supplied to the heater load  516 . In this manner, the temperature generated by the heater load  516  then can be increased or decreased in response to the information provided by temperature sensors  518 , and remote sensors  522 . Controller  510  can increase the temperature of the heater load  516  at a predetermined rate to aggressively approach a surface target temperature. Controller  510 , together with the temperature sensors  518 , and remote sensors  522 , can be considered to be a closed proportional-integral derivative circuit. Using a controlled fixed rate of increase in the power applied to heater load  516  can reduce the thermal shock to the heat treatable materials that are disposed within the interior space of the heating enclosure. A triac used in the driver circuit  512  clips the sinusoidal waveform of the AC circuit that is applied from the bulkhead connector  504  to reduce delivered power. For example, to cut the delivered power by 50 percent on a 60 hertz system, the triac would clip half of the waveform. Although only a single heater zone  524  is illustrated, multiple heater zones may be utilized. In that case, controller  510  can function to reduce instantaneous power consumption by zero-cross switching and distributing the AC power across the multiple heating zones. For example, if a first heating zone requires 25 percent power and a second heating zone requires 50 percent power, the controller can synchronize a first triac to conduct for 15 cycles per second. The controller can also control a second triac to conduct 30 cycles per second and stop conducting for the next 15 cycles per second. In this manner, multiple triacs can be used to supply power to different heating loads. 
     Referring to Table 1, a preselected temperature and the period of time for treatment can vary depending on the pest which is being caused to egress from within, or from the external surface of, the enclosure body, or which is being killed within the enclosure body, or on the external surface of the enclosure body, in association with the heat treatable material. For the purposes of this invention the term “pest” encompasses a wide range of pathogens, molds, or insects (whether as adult, larvae, or eggs). 
     
       
         
               
               
               
               
             
               
               
               
               
               
             
               
               
               
               
             
               
               
               
               
               
             
               
               
               
               
             
               
               
               
               
               
             
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                 Temperature 
                 Time 
               
               
                   
               
             
             
               
                 Pathogen 
                 Enteric viruses 
                 60 C. 
                 Rapidly 
               
             
          
           
               
                   
                 
                   Salmonellae 
                 
                 60 C. 
                 20  
                 Hours 
               
               
                   
                 
                   Shigellae 
                 
                 55 C. 
                 60  
                 Minutes 
               
             
          
           
               
                   
                 
                   E. 
                   coli 
                 
                 60 C. 
                 Rapidly 
               
             
          
           
               
                   
                   Entamoebahystolytica  cysts  
                 50 C. 
                 5  
                 Minutes 
               
               
                   
                 Hookworm eggs 
                 50 C. 
                 5  
                 Minutes 
               
               
                   
                 Roundworm eggs 
                 55 C. 
                 120  
                 Minutes 
               
               
                 Molds 
                 Wood Fungi (Staining Fungi) 
                 66 C. 
                 75  
                 Minutes 
               
             
          
           
               
                   
                 
                   Basidiomycotina 
                 
                 50 C. 
                 N/A 
               
             
          
           
               
                   
                   Poria  - Wood Eating Fungi 
                 66 C. 
                 75  
                 Minutes 
               
               
                   
                 ( Meruliporia   Incrassata ) 
                   
                   
                   
               
               
                   
                   Fomes  ( Fomitopsis   Rosea ) 
                 66 C. 
                 75  
                 Minutes 
               
               
                   
                 
                   Stachybotrys 
                   Chartarum 
                 
                 60 C. 
                 30  
                 Minutes 
               
               
                   
                 
                   Aspergillus 
                   Alutaceus 
                 
                 62 C. 
                 20  
                 Minutes 
               
             
          
           
               
                   
                 
                   Aspergillus 
                   Acandidus 
                 
                 62 C. 
                 N/A 
               
             
          
           
               
                   
                 
                   Aspergillus 
                   Ustus 
                 
                 62 C. 
                 25  
                 Minutes 
               
               
                   
                 
                   Aspergillus 
                   Wenti 
                 
                 63 C. 
                 25  
                 Minutes 
               
               
                   
                 
                   Aspergillus 
                   Niger 
                 
                 63 C. 
                 25  
                 Minutes 
               
               
                   
                 
                   Alternaria 
                   Alternata 
                 
                 63 C. 
                 25  
                 Minutes 
               
               
                 Insects 
                 Bed Bug Adults &amp; Nymphs 
                 45 C. 
                 15  
                 Minutes 
               
               
                   
                 Bed Bug Eggs 
                 45 C. 
                 60  
                 Minutes 
               
               
                   
                 German Cockroach - Adult Male 
                 49 C. 
                 27  
                 Minutes 
               
               
                   
                   
                 54 C. 
                 7  
                 Minutes 
               
               
                   
                 Flour Beetle 
                 49 C. 
                 16  
                 Minutes 
               
               
                   
                   
                 54 C. 
                 4  
                 Minutes 
               
               
                   
                 Drywood Termite Nymphs 
                 49 C. 
                 30  
                 Minutes 
               
               
                   
                   
                 54 C. 
                 6 
                 Minutes 
               
               
                   
                 Agentine Ant (Adults) 
                 49 C. 
                 4  
                 Minutes 
               
               
                   
                   
                 54 C. 
                 1  
                 Minute 
               
               
                   
               
             
          
         
       
     
     Hence, the various embodiments disclosed herein provide various ways of killing bedbugs, or other pests, in containers and causing such pests to egress from surfaces of the container. Various types of containers are disclosed, including suitcases, standard boxes, trailers, trucks and similar devices. The various types of containers and enclosures can be retrofit with a heating film or a resistive wire heating element to create an enclosure that is capable of killing pests. These enclosures can also be retrofit with various controllers, including a user interface, as well as simple controllers, such as a bimetallic switch. This system uses simple surface heaters on multiple sides of the enclosure, such as heating film and resistive wire heating layers. Inexpensive control systems are used, including bimetallic switches, closed loop controllers, and other systems. Heating films are ideal for use on the various enclosures since they are low cost, extremely thin, lightweight and pliable, and can produce optimal temperature ranges for killing pests. Further, infrared wavelengths, on the order of 50 to 1000 nanometers, that are generated by the heating film, allow the heat to penetrate materials within the enclosure, rather than relying upon convective air currents. Heating films are safe to use and can be either custom designed for application directly to an enclosure or provided in a pre-made film having various widths. 
     The foregoing description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and other modifications and variations may be possible in light of the above teachings. The embodiment was chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and various modifications as are suited to the particular use contemplated. It is intended that the appended claims be construed to include other alternative embodiments of the invention except insofar as limited by the prior art.