Abstract:
An apparatus for warming substances comprising a container, said container including a first compartment containing a substance that reacts exothermically with water, a second compartment containing water, wherein said second compartment is attached to said first compartment by a valve, and a third compartment, wherein at least 50% of the third compartment&#39;s volume is surrounded by said first compartment, and wherein said first and third compartments are separated by a thermally conductive wall. In a preferred embodiment, the substance that reacts exothermically with water is an anhydrous zeolite.

Description:
[0001]    This invention relates to systems and methods for containers that can warm their contents using an exothermic reaction, such as mixing water with anhydrous zeolites. This application claims benefit under 35 U.S.C. §120 of the filing date for application No. 61/790,297 filed Mar. 15, 2013. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    It is often desirable to be able to heat or reheat items like meals or baby bottles while on the go, away from the convenience of typical heating units such as microwaves. Many portable warming devices rely on power cords, which necessitate the availability of power outlets, to warm their contents. Other such portable warming devices rely on battery power, which have a limited life span, or electrical heating components, which present the possibility of component failure or wear out. Many “cordless” portable devices require time-consuming charging or recharging periods each time the device is used. Additionally, many such portable heating devices only warm their contents but provide no method of maintaining temperature prior to the warming process. 
         [0003]    A novel self-warming container presents a solution to these dilemmas. The container warms its contents at the touch of a button by harnessing heat generated from an internal and enclosed exothermic reaction. To recharge the container for additional uses, one need only microwave the container for a few minutes, resetting the chemical reaction to its initial state. The container is then ready to heat its contents again minutes or even days later. The self-warming container has an array of uses, from heating food for lunches and picnics to warming baby bottles and wipes. The self-warming container can take a variety of configurations depending on its intended use. The invention is especially well suited for food storage, as the design allows it to maintain a relatively constant temperature even prior to warming. Therefore, if refrigerated, the container will keep food cool for a significant amount of time prior to warming. 
       BRIEF SUMMARY OF THE INVENTION 
       [0004]    The invention is a self-warming container, which requires no outside energy input (such as power cords or batteries) to warm its contents other than the addition of water prior to use. The container will begin to warm contents at the touch of a button, so that the user has control of when the contents are to be heated. Additionally, the container only need be heated in the microwave or oven for a few minutes and the water replenished to recharge the heating capabilities of the unit before the next use of the device. In some embodiments of the invention, due to the thermal mass of the container, it could also be used to keep food at a cool temperature prior to warming, if the container is stored in a cool environment, like a refrigerator, prior to use. 
         [0005]    To prepare the device for heating, water is added to an internal water reservoir in the container. To initiate warming, a button adjacent to the water reservoir is depressed. When the button is depressed, the water mixes with a heat producing substance. The interaction between the water and the heat-producing substance causes an exothermic reaction, and the heat is dissipated to the container to warm the contents. 
         [0006]    To reset the heating process, the container is microwaved or placed in the oven to dehydrate the heat-producing substance, which causes the heat-producing material to “reset” itself. Water vapor escaping the container during this “resetting” is vented through a one way valve leading away from the container or is condensed back into the water reservoir. The valve seals itself so that water vapor form the ambient air cannot enter the container and inadvertently interact with the heat producing material. 
         [0007]    There are a number of possible configurations for the invention, based on the size and type of contents to be warmed. For each configuration the method of heating is the same as detailed above. All embodiments include at least one compartment for contents to be warmed and at least one water reservoir compartment, with a surrounding thermal shell for temperature control and heating. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0008]      FIG. 1 . Example of one possible design of the container. 
           [0009]      FIG. 2 . Depiction of differing states of the start button. 
           [0010]      FIG. 3 . Cutout side view of internal aspects of container in  FIG. 1 . 
           [0011]      FIG. 4 . Two additional possible configurations and uses of the container. 
           [0012]      FIG. 5 . Schematic of internal components of container, side view. 
           [0013]      FIG. 6 . Detail of water vapor release valve and water reservoir valve. 
           [0014]      FIG. 7 . Cross-section of self-warming container with removable zeolite cartridge. 
           [0015]      FIG. 8 . Detail of cross-section of self-warming container with removable cartridge showing juncture of cartridge with water compartment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Basic Design 
       [0016]    The design of the invention can take on any number of configurations, depending on the intended use of the device. All configurations have at least the following components: an internal compartment for storing the contents to be warmed, an internal water reservoir compartment, an outer shell which houses the heat-producing substance and reaction, and a button by which the user can initiate the heating reaction. In some embodiments of the invention, a one-way valve connects the outer shell to the ambient atmosphere, allowing water vapor to escape the device. In other embodiments, water vapor is condensed back into the water reservoir chamber. 
         [0017]    To warm contents of the container, the outer button is depressed, which opens a valve between the water reservoir and heat-producing substance. Such a substance would produce an exothermic reaction when hydrated, so the mixture of the two compartments would release heat to the internal contents of the container, thereby heating the contents. To reset the container for future uses, the device is placed in the microwave or oven to dehydrate the heat-producing substance, reversing the reaction and restoring the container to its original state. The water reservoir is refilled with water, and the container is again ready to be used to warm its contents with the push of a button. 
         [0018]    Due to the need for the container to contact food and also be exposed to a wide range of temperatures, the materials for construction of the container need all be of food-grade quality, as determined by the Food and Drug Administration (FDA). In addition, because the container may be microwaved or placed in the oven to recharge the heat-producing substance, but could also be stored in the refrigerator, the materials of construction must be able to withstand a wide range of temperatures, especially high temperatures. In some embodiments of the invention, these construction materials could be a number of different food-grade silicone rubbers or other materials which meet the criteria outline above. In addition, all spring and valve-like components would also be made of temperature resistant, non-metallic materials to prevent sparking when heated. 
       CONTENTS COMPARTMENT 
       [0019]    In all configurations of the invention there is at least one internal compartment  101  to hold the contents to be warmed, such as food, liquids, lotions, or towlettes. This compartment  101  can take on different sizes and shapes dependent on the intended use. Such a compartment can be seen in  FIG. 1 , which illustrates one possible embodiment of the invention. The wall of the contents compartment is made of a heat- and cold-resistant material to prevent damage due to frequent heating and cooling. The material should also be of food-grade quality for consumer safety. Water Reservoir: 
         [0020]    All configurations of the invention also contain at least one internal compartment  301  for holding water, which is separated from the contents to be heated by internal walls  302 , seen in the cut-out view in  FIG. 3 . There is an opening  102  at the top of the device above the water reservoir  301  for additional water to be added between uses. The water reservoir  301  is connected to the outer shell of the container  303  and heating substance  304  by a valve  501  which has a default position of closed to prevent mixture of the two compartments until it is desired, as illustrated in  FIG. 5 . 
       OUTER SHELL AND HEATING METHODS 
       [0021]    An outer shell  303  surrounds the contents and water reservoir compartments of the invention. The outer shell is separated from the other compartments by internal walls  302 ,  306 . In one embodiment of the invention, illustrated in  FIG. 3 , the outer shell is comprised of three layers: an outer wall made of thermally insulated material  305 , an inner wall of the same food-grade resistant material that defines the internal compartments  306 , and an internal space between the two walls which houses the heat-producing substance  304 , which surrounds the internal compartments  101 ,  301 . The water reservoir  301  is connected to the outer shell  303  via a valve  501 , illustrated in  FIG. 5  (for details, see  FIG. 6 ). When the user depresses a button  103 , a spring  502  engages and the valve  501  is opened, allowing water to flow into the internal space of the outer shell  304  and react with the heat-producing substance. This heat producing substance could be a number of different natural or synthetic zeolite materials that possess a strong affinity for water. Zeolites are aluminosilicate substances that undergo an exothermic reaction when hydrated. When water from the reservoir  301  enters the outer shell  303  and meets the zeolite or similar material, the zeolite is hydrated and an exothermic reaction occurs, giving off heat to the surroundings. This heat generation warms the internal contents of the container. The thermal insulation of the outer wall of the container  305  prevent the outside of the container from becoming too warm, and prevents heat loss outside the container, thereby improving heating of the internal contents. Zeolites are able to hydrate and dehydrate indefinitely while maintaining structural stability, allowing the heating reaction to be reversed and the container to be used to warm contents hundreds or thousands of times. In some embodiments of the invention, the zeolite or similar heating-producing substance is completely enclosed within the walls of the invention (see  FIG. 3 ). 
         [0022]    Additionally, due to the insulated outer layer of the container and the thermal mass of the container as a whole, the temperature of the invention will remain relatively constant even prior to warming. To this effect, it is possible that in some embodiments of the invention, such as in food storage, the self-warming container could be stored in the refrigerator prior to use, and the container would maintain its refrigerated temperature prior to the start of the warming process. 
       POWER BUTTON AND INITIATION MECHANISM 
       [0023]    All configurations of the invention have a start button  103  which activates the warming container. The button  103  is comprised of two individual components, as seen in  FIG. 2 : a depressible button  201  and outer elastic covering  202 . The button  201  and the elastic covering  202  could be different colored materials, such as a yellow button and a semi-transparent blue covering. In its initial state, the yellow button  201  and the blue covering  202  are both in the upper position and in close proximity to each other, as seen in  FIG. 2   a . Because of the differing colors of the plastics, the button will appear one color to the user (in this instance, green). When the mechanism is depressed, initially both the button  201  and the covering  202  will be in the down position, but the elastic cover  202  will revert to its upper position due to its elasticity, as seen in  FIG. 2   b . Because of the separation of the button  201  and elastic cover  202 , the mechanism will now appear a different color to the user (in this case, blue). 
         [0024]    Internally, the button connects to a spring  502  which runs the length of the water reservoir  301 . This spring is connected at the opposite terminal to the valve  501  controlling the separation of the water reservoir and the heat-producing substance. When the user depresses the button  103 , the spring engages the valve and opens the separation between the water reservoir and the heat-producing substance. In this manner, the user controls when the container begins to heat its contents by starting the heating reaction by pressing the button. Steam Releasing Valve: 
         [0025]    In some embodiments of the invention, to reset the container after it is used for heating it must be placed in the microwave or oven to dehydrate the heat-producing material. During dehydration, the water which interacted with the heat producing material will be evaporated. To allow for this water vapor to escape the outer shell  303 , a one-way valve  602  connects the inner space of the shell to the ambient atmosphere (see  FIG. 6  for details). One possible embodiment of this valve is a spring-activated valve biasing the valve closed against the container. When the container is heated and enough water vapor produced, the vapor pressure overcomes the force of the spring and forces the valve  602  open to allow the vapor to escape. When the pressure is reduced after the elimination of water vapor, the spring seals the valve closed again to prevent moisture from the ambient air from interacting with the heat-producing substance  304 . In still other embodiments, the water vapor may be vented back to the water reservoir  301  and condensed on the cooler walls of the compartment, rather than or in addition to venting to the ambient atmosphere. 
       HEATING CARTRIDGE DESIGN 
       [0026]    In one embodiment of the invention, shown in  FIGS. 7 and 8 , the heating substance such as zeolites  702  could be enclosed in a removable and replaceable cartridge  703 , rather than inherent to the device. In this way, the container could be used to warm many times by simply replacing a used heating cartridge with a recharged cartridge, rather than recharging the entire device in the microwave or oven, in cases where no such operation is possible. Rather, individual heating cartridges could be switched out when they have been used, and could be recharged in the microwave or oven after use. In such a design, the heating substance is present in an enclosed component which is separate from the main body of the container. The main body of the container could contain the main compartment to hold the contents to be warmed  701 , the water reservoir  706  and associated start button and spring valve  707 , and parts of the outer shell compartment  705 . A separate cartridge houses the heating substance  702  in a completely enclosed compartment comprised of materials similar to those described above. When one desires to use the container, the cartridge is situated into the main container as seen in  FIG. 7 , in the outer shell area  704 ,  705  of the main container. 
         [0027]    To connect the heating cartridge to the main container, there could be a moveable or pivoting portion of the main container outer wall  709 , creating a door or port cover, which allows room for the cartridge to be positioned into place. This door or port cover would engage the cartridge and lock it in place, possibly via a spring-loaded mechanism. To provide continuity from the water reservoir in the main container  706  to the cartridge containing the heating material, there could be a junction  708  which allows the end of the heating cartridge to snap or fit up against the end of the water reservoir when it is positioned in the main container. Additionally, a removable barrier component  710  could be present in the heating cartridge to prevent external moisture from entering the heating substance  702  before the cartridge is positioned on the main container. The water-vapor release valve could be present in this heating cartridge, rather than on the main container as in other embodiments.