Abstract:
The invention relates to a portable package and method for preparing a meal. A warm meal is prepared by taking dehydrated food within a package and combining it with non-boiling water. The mixture is then heated by an electrical, portable power source, such as a battery or vehicle power system. This allows a warm meal to be prepared almost anywhere, even without access to boiling water.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims priority to and incorporates by reference in its entirety U.S. Provisional Application No. 60,696,521, filed Jul. 6, 2005, titled “INTEGRATED HEATER FOR FOOD PACKAGING”. 
     
    
     TECHNICAL FIELD  
       [0002]     The following relates to an apparatus and method for providing heating within food packaging.  
       BACKGROUND  
       [0003]     For many applications, quick-prepared food kits are necessary for nourishment when traditional cooking supplies are not accessible. As examples, military soldiers, astronauts, and recreational campers often must rely upon food rations that will provide nourishing and filling meals without requiring a significant amount of time, effort, or supplies to prepare for consumption. For some applications, the food kits are known as “MREs”, or “meals ready to eat”.  
         [0004]     One type of quick-prepared food kit consists of freeze-dried food within sealed packaging. The freeze-dried food may include meat that already has been cooked before having been dehydrated for long-term storage and portability without refrigeration. To prepare the food, the consumer opens the package and pours approximately 1-2 cups of boiling water inside. The food is hot once again in just a few minutes. The packaging contains the food to enable the consumer to consume the meal directly from the pouch. Typically, the serving size, calories, carbohydrates, sugars, and protein are pre-measured to ensure that a complete meal is included in the package.  
         [0005]     While such food kits are portable and can be prepared very quickly with a minimum of tools and other supplies, it is still necessary to have a source of hot or boiling water to pour into the bag and re-hydrate the food. For campers or hikers, the only source of hot water may be from a campfire. Military soldiers and astronauts may need to rely upon other sources for hot water, which may be inconvenient or rarely accessible. In some circumstances, this may significantly impact the usefulness of the product.  
         [0006]     Since access to heated water is often limited, one known mechanism for heating MREs is to use a chemical heater pack to provide “self-heating.” Water is added to the packaging and the heater is placed next to the packaging. The heater includes magnesium metal, which when mixed with water, forms magnesium hydroxide, hydrogen, and heat. Typically, the meal is ready to be consumed within approximately 15 minutes.  
       SUMMARY 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     Additional embodiments will be more apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout, and in which:  
         [0008]      FIG. 1  is an illustration of packaging for a quick-prepared food kit;  
         [0009]      FIG. 2  is a perspective view of packaging for a quick-prepared food kit;  
         [0010]      FIG. 3  is an illustration of a heater integrated within packaging for a quick-prepared food kit in accordance with an embodiment of the present invention;  
         [0011]      FIG. 4  is an illustration of electrode contacts and steam vents integrated within packaging for a quick-prepared food kit in accordance with an embodiment of the present invention;  
         [0012]      FIG. 5  is a schematic representation illustrating power source options and other circuitry for integrating a heater within packaging for a quick-prepared food kit in accordance with an embodiment of the present invention;  
         [0013]      FIG. 6  is a chart providing power, current, and resistance requirements for a 250 ml quick-prepared food kit package, in accordance with an embodiment of the present invention;  
         [0014]      FIG. 7  is a chart providing power, current, and resistance requirements for a 350 ml quick-prepared food kit package, in accordance with an embodiment of the present invention;  
         [0015]      FIG. 8  is a chart providing heater calculations for a 12 V DC power supply; and  
         [0016]      FIG. 9  is a chart providing heater calculations for a 28 V DC power supply. 
     
    
     DETAILED DESCRIPTION  
       [0017]     The following discloses a heater assembly is integrated within packaging of a quick-prepared food kit. Preferably, the heating assembly uses one or more flexible, semiconductive, electrically resistive heating elements powered by a source of electrical power. This embodiment&#39;s heater assembly withstands the stresses that can break and disconnect an electrical wire-based heater and efficiently provides quick heating capability with reduced power requirements. The integrated heater is designed to be disposable once the meal within the packaging is consumed.  
         [0018]      FIGS. 1 and 2  illustrate exemplary quick-prepared food kits, or “MREs” that may be adapted to incorporate the integrated heating system in accordance with the present invention. The packaging consists of a flexible foil  20  that is designed to keep the food sealed from external elements. The packaging is lightweight, easily portable, compressible, and durable to impact. The exterior laminate(s) may use common materials such as nylon, polyethylene, polypropylene, polyester, or metal film, along with printed layers for branding and instructions. In some embodiments, to unseal the packaging, a tear portion  10  is included to enable consumers to easily tear open the packet without requiring any tools.  
         [0019]      FIG. 3  illustrates an integrated heating system that may be used in accordance with an embodiment of the present invention. Although the outside packaging  34  appears as a standard, quick-prepared food kit, the interior of the packaging  32  includes a semiconductive heating element  30 , preferably in a serpentine configuration. The inner laminate within the packaging may be made of any of nylon, polyethylene, polypropylene, polyester, metal film, or other common materials in the packaging industry.  
         [0020]     The heating element is flexible to bend along with the packaging  34 . Metallic contacts  33   a  and  33   b  connect to a power source to provide an electrical circuit to turn on the heater and start warming the package once water is added. In some embodiments, water is already added such that all that is needed is heating provided by the heating assembly.  
         [0021]     The resistive heating element may include, for example, but is not limited to a graphite or carbon foil, or it may be a felt or fabric encased within the packaging. The heating element is designed for the intended power source, such as a 12 V DC automobile or a 28 V DC military system.  
         [0022]     In one example, the metallic contacts  33   a  and  33   b  can be connected to a military vehicle, using on-board power device clamps. As another example, the contacts can be connected to a vehicle power adapter, such as through a cigarette lighter. As further examples, the contacts also may be connected to a rechargeable power device or to vehicle battery terminals.  
         [0023]      FIG. 4  illustrates an optional protective label cover for the exterior of the packaging, in accordance with a further exemplary embodiment of the invention. Flexible packaging  40  includes a protective label cover  43 , which peels back to expose a terminal  42  and a micro-perforated steam vent  44 . This protects the vent and terminal during transport and storage while enabling easy access during heating. When the protective label is fully removed from the packaging  45 , both terminals  46  and  47  are exposed, along with the vent  48 . The micro perforations in the vent allow steam to vent but impede liquid water from exiting, for proper heating in some circumstances.  
         [0024]      FIG. 5  illustrates a schematic with several possible power sources and other circuitry that may be associated with the heating system. Particularly, the heater  50  can connect through contacts  51   a  and  51   b  to a car adaptor  52   a , vehicle battery terminals  52   b , an in-vehicle connection  52   c , a rechargeable device  52   d , or other power sources. The spacing of the contacts  51   b  and  51   a  can be determined to easily connect the packaging to battery terminals having the same geometry. A 12 V DC power source is acceptable, although 28 V DC is preferred to minimize heating time. The heater element geometry varies according to the voltage and power requirements, as will be described further below.  
         [0025]     As also shown in  FIG. 5 , the packaging may also optionally include an over-current fuse  54  to prevent damage to the input power source.  
         [0026]     Significantly, as an optional embodiment, the heating element can additionally include a thermal fuse  53  designed to create an open circuit when the food and water have received a determined amount of heat energy. This is useful to prevent overcooking or undercooking. A thermal fuse indicator, such as an LED, can be included to inform the consumer that the meal in the food kit has been prepared appropriately.  
         [0027]      FIG. 6  is a chart providing power, current and resistance requirements for a 250 ml quick-prepared food kit package, in accordance with an embodiment of the present invention. As can be seen, assuming a package that can contain 250 ml of water, with an initial temperature of 20° C. and a desired final temperature of 95° C., charts are provided that indicate the power, current, and resistance for given times and time, current, and resistance for given power to temperature. Similarly,  FIG. 7  is a chart providing power, current, and resistance and time, current, and resistance for an integrated heater used in a 350 ml package. The package can be made in other sizes as well. Various pre-proportioned quantities of food can be packaged with instructions for the appropriate amount of water to add.  
         [0028]      FIG. 8  is a chart providing heater calculations for a 12 V DC power supply. Particularly, for a 12 V supply, as power is varied, the current, resistance, and length to width ratio is provided. As the length is varied, the width and area are provided as well.  
         [0029]     Lastly,  FIG. 9  is a chart providing heater calculations for a 28 V DC power. Similar to  FIG. 8 , as power is varied, the current, resistance, and length to width ratio is provided. As the length is varied, the width and area are provided as well.  
         [0030]     From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.