Abstract:
A food storage container that is double-walled and transportable. The space or compartment between the two walls insulates the food contents of the container. The compartment between the walls may contain water, refrigerant gel, styrene or filler of the user&#39;s choice. The walls of the container are very thin and malleable.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Application Ser. No. 60/806,848 filed Jul. 10, 2006. 
     
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a food storage container and more particularly to a portable food storage container that is double-walled for purposes of insulating the inner compartment and its contents. 
         [0004]    2. Description of the Prior Art 
         [0005]    Food storage containers are widely used in households across America. These are typically made of a plastic, and include a body forming a storage space with an open mouth and a lid closing the mouth. The container has thin walls to increase the usable storage space and reduce manufacturing costs. Typically the containers are shaped and sized to store several bodies to be nested when not in use. The base typically holds food items or beverages and the lid seals the container shut. The container can be stored in the refrigerator or freezer to cool or preserve the contents. Alternatively, the container can also be put in the microwave to heat or cook the contents. The containers are easily transportable and come in a variety of shapes, sizes, colors, etc. Containers of this type are available, for example from the Tupperware, Inc. of Orlando, Fla. and others. 
         [0006]    A disadvantage of these containers is that because of the thin walls the temperature of the contents cannot be maintained above or below the ambient temperature. In all containers, the environment will first transfer thermal energy to or take thermal energy away from the container bringing the temperature of said container itself towards the temperature of the environment it is in. Single layer plastic containers offer little insulation to the food. This makes it difficult to transport the containers while maintaining the preferred temperature of the food. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention generally involves an improved container for storing and serving foods or beverages. The present invention aims to provide a portable double-walled food storage container that insulates the contents to maintain a desired temperature. The container has an inner wall, which holds the substance being stored, and an outer wall exposed to the outside environment. The container walls are very thin and are preferably manufactured using molding technology. The space between the outer wall and inner wall (optionally) contains fluids that insulate the inner compartment. 
     
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0008]    To further satisfy the recited objectives, a detailed description of typical embodiments of the invention is provided with reference to appended drawings that are not intended to limit the scope of the invention, in which: 
           [0009]      FIG. 1  is a front view of a preferred embodiment of a container with lid; 
           [0010]      FIG. 2  is a cross-section view of the container consistent with the embodiment of  FIG. 1  without a lid; 
           [0011]      FIG. 3  is a top view of the container of a second embodiment with a lid; 
           [0012]      FIG. 4  is a top view of the container of  FIG. 1  with the lid. 
       
    
    
     DESCRIPTION OF THE INVENTION 
       [0013]    The present invention may be embodied in several forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not as restrictive. The scope of the invention is, therefore, indicated by the appended claims and their combination in whole or in part rather than by this description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope. 
         [0014]    The present invention is a container apparatus for storing and serving foods or beverages. The container has an inner wall, which defines a chamber that holds the substance being stored, and an outer wall exposed to the outside environment. The two walls are separated creating a compartment between the two layers. The distance between the two walls can be substantially uniform throughout the container or can vary. The container is provided with a standard snap-on closure or lid. The container can be in the shape of a cylinder, sphere, cube, tetrahedron, hexahedron or any other three-dimensional regular or irregular shape. A material, preferably one with high thermal coefficient, is placed in the compartment for the purpose of providing thermal insulation. 
         [0015]    In an advantageous embodiment, the space or compartment between the inner and outer wall contains a fluid that insulates the contents of the inner chamber. The costumer, preferably, can select the type of fluid inserted into the space. In this embodiment an opening is provided that can be used to selectively fill the compartment with a suitable fluid. Once the fluid is introduced, a plug or other closing means are used to seal the compartment shut. Alternatively, in one embodiment, the compartment is filled with an appropriate fluid having a high thermal resistivity, and then the compartment is sealed so that the customer cannot access it. 
         [0016]    A customer will be able to cool or heat the liquid in between the two walls with or without anything in the storage space itself. The container can be heated using a conventional microwave device, or by being emerged in a high temperature environment (e.g. hot water). The container can be cooled by being placed in a conventional freezer, refrigerator or otherwise being immersed in a very cold environment. This will also increase or decrease the temperature of the two walls comprising the rest of the container as well as the liquid there between. Once exposed to the outside environment, the liquid inside the container and the container itself will begin to lose or gain thermal energy, thus decreasing or increasing in temperature. But this change in temperature will happen much less rapidly than if a single walled container is used. In an alternate embodiment, the container is at ambient temperature and is filled with hot or cold materials, such as food stuff. 
         [0017]    Once the compartment is filled, the substance between the two walls, whether a liquid or a gas, is trapped, therefore creating minimal contact between the wall and the substance for thermal energy to transfer. This principal is the same as that used in double-pane windows. 
         [0018]    As previously mentioned, the fluid in the space chamber may be a liquid or a gas. In one embodiment, this liquid may be a mixture of 3 to 10 percent and preferably 5 percent hydroxyethyl cellulose and 90 to 97 percent and preferably 95 percent propylene glycol. Propylene glycol is a non-toxic anti-freeze agent with colligative properties. Alternatively the liquid could be refrigerant gel. Preferably, the gel has a freezing temperature of about −1° Celsius. Such a refrigerant gel may consist of about 15% by weight of cornstarch, about 2% by weight of borax, about 0.01% by weight of a preservative, and remaining weight in water. The preservative in the refrigerant gel can be potassium sorbate, which is non-toxic. In a third embodiment, the compartment is filled with water. In a fourth embodiment, the compartment can be filled with expanded polystyrene, which is a plastic foam. In a fifth embodiment, the compartment is depressurized to create at least a partial vacuum. 
         [0019]    A typical container constructed in accordance with this invention is shown in  FIGS. 1-4 . It should be understood that in the figures are not drawn to scale and that the walls and the compartment between of the walls are shown as being much wider then they are as compared to the overall dimensions of the container for the sake of clarity. More particularly, in the Figs. a container  10  is shown including a snap-on lid  13 , and an outer wall  15 . The container  10  is preferably made of a conventional lightweight plastic that has strong durability properties. It is preferably made of very thin plastic that is flexible and soft but can be formed of any material that is proper for use in a food container. The snap-on lid  13  preferably provides an airtight seal so that during transport the food contents do not leak from container  10 , and are protected so that they do not spoil very fast. The outer wall  15  encloses the container from the outside environment. 
         [0020]      FIG. 2  of the present invention shows container  10 , outer wall  15 , outer wall floor  19 , inner wall  17 , inner wall floor  21 , inner chamber  20 , and a compartment  23  formed between the walls  15  and  17  and floors  19  and  21 . Compartment  23  is sealed. A fluid  24  is introduced in compartment  23  as discussed above. The fluid may be anti-freeze, refrigerant gel, water, foam or a fluid that is non-toxic. The chamber  20  holds the food stuff or any other desired material. The inner wall  17  acts as a barrier between the contents of the compartment  23  and the food contents of the inner chamber  20 . 
         [0021]    As shown in  FIG. 2 , the container is formed with a top member  25  that seals the compartment  23 . The fluid  24  remain in the compartment  23 . The top member  25  provides a peripheral lip  27  that is engaged by an inner groove  29  of the lid  13 . The lip  27  and groove  29  cooperate to releasably seal the container. Of course, it should be understood that the container could be provided with many other interlocking profiles as well. 
         [0022]    As mentioned above, in one embodiment the container  10  is formed and shipped to customers with its compartment pre-filled with an appropriate fluid  24 . In an alternate embodiment, as shown in  FIG. 3 , a container is provided with a top member  30  formed with an opening  33  leading into the compartment  23  and a plug  35 . The customer can remove the plug  35  and fill the compartment with any fluid  24  he desires. 
         [0023]    As shown in  FIG. 4 , the container is formed with a top member  25  that seals compartment  23 . 
         [0024]    The containers may be shaped so that several of them can be nested inside each other without the tops. 
         [0025]    Although the invention has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the application of the principles of the invention. Numerous modifications may be made therein and other arrangements may be devised without departing from the spirit and scope of the invention.