Abstract:
A composite food storage container combines the advantages of glass and polymer while avoiding their disadvantages. A composite food storage container may include an outer polymer container that is configured to accommodate a glass container within the polymer container. Since the food does not contact the polymer, there are no potential concerns with chemicals leeching into the food. Since the glass is surrounded by the polymer container, the glass is protected from breakage and the composite food storage container does not become too hot to easily and safely handle upon removal from a microwave oven.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/327,359, filed on Apr. 23, 2010, and U.S. Provisional Patent Application Ser. No. 61/386,322, filed on Sep. 24, 2010, both of which are incorporated by reference herein in their entireties for all purposes. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention pertains generally to storage containers and more particularly to food storage containers that are microwave and oven safe. 
       BACKGROUND 
       [0003]    Many individuals are in the habit of bringing their own lunch to school and work by packing food in one or more food storage containers that are then carried in a paper, fabric or polymeric container. Some people, for example, simply use a disposable paper bag to carry their lunch. Some people have fabric bags or lunch boxes that they use to carry their lunch. The food storage containers may be plastic, metal or glass. Each of these materials have advantages and disadvantages. 
         [0004]    Metal food storage containers are strong and not easily damaged, but they cannot be used in a microwave oven. Plastic food storage containers are resistant to damage and can be used in a microwave oven. However, some people are reluctant to use plastic in a microwave oven due to concerns over chemicals in the plastic potentially leeching into the food. Glass food storage containers can be used in a microwave oven, but glass is easily breakable. Glass containers can become too hot to easily handle. 
       SUMMARY 
       [0005]    The present invention, according to various embodiments, relates to a composite food storage container that combines the advantages of glass and polymer while avoiding their disadvantages. In some embodiments, a composite food storage container may include an outer polymer container that is configured to accommodate a glass container within the polymer container. The polymer may be plastic, silicone, and/or another material. Since the food does not contact the polymer, there are no potential concerns with chemicals leeching into the food. Since the glass is surrounded by the polymer container, the glass is protected from breakage and the composite food storage container does not become too hot to easily and safely handle upon removal from the microwave oven. 
         [0006]    In some embodiments, the polymer container may include shock-absorbing ribs that are disposed along an interior surface of the polymer container. The glass container may rest on the shock-absorbing ribs and thus be protected from damage. In some embodiments, the polymer container may include a non-slip lower surface. In some embodiments, the composite food storage container may include a lid that can be moved from closed to open in only a quarter turn. In some cases, the lid may make an audible noise such as a click when the lid reaches its closed position. 
         [0007]    In some embodiments, the outer container and the lid have a substantially circular cross-sectional shape, and in other embodiments, the outer container and the lid have a substantially square or rectangular cross-sectional shape. According to some embodiments of the present invention, the lid sealingly engages with a top rim of the inner bowl, while according to other embodiments, the lid sealingly engages with an outer surface of the inner bowl. According to some embodiments of the present invention, the lid engages a top of the outer container, while according to other embodiments, the lid engages an outer surface of the outer container. According to some embodiments of the present invention, the outer container and the lid are both made of silicone. 
         [0008]    While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0009]      FIG. 1  is a perspective view of a composite food storage container in accordance with an embodiment of the invention. 
           [0010]      FIG. 2  is a perspective view of the composite food storage container of  FIG. 1 , with the cover and glass container removed to better illustrate the internal structure of the polymer container. 
           [0011]      FIG. 3  is a perspective view of the glass container forming part of the composite food storage container of  FIG. 1 . 
           [0012]      FIG. 4  is a cross-sectional view of the composite food storage container of  FIG. 1 , with the glass container removed for clarity. 
           [0013]      FIG. 5  is a perspective view of the underside of a cover forming part of the composite food storage container of  FIG. 1 . 
           [0014]      FIG. 6  is a top view of the polymer container forming part of the composite food storage container of  FIG. 1 . 
           [0015]      FIG. 7  is a front perspective view of a composite food storage container, according to embodiments of the present invention. 
           [0016]      FIG. 8  is a front perspective view of composite food storage container of  FIG. 1 , without the lid, according to embodiments of the present invention. 
           [0017]      FIG. 9  is a bottom perspective view of a lid, according to embodiments of the present invention. 
           [0018]      FIG. 10  is a front and top perspective view of a bowl cover, according to embodiments of the present invention. 
           [0019]      FIG. 11  is a back and top perspective view of the bowl cover of  FIG. 10 . 
           [0020]      FIG. 12  is a front elevation view of the bowl cover of  FIGS. 10 and 11 , and the back, left side, and right side elevation views are identical to the front elevation view of  FIG. 12 , according to embodiments of the present invention. 
           [0021]      FIG. 13  is a top view of the bowl cover of  FIGS. 10-12 . 
           [0022]      FIG. 14  is a bottom view of the bowl cover of  FIGS. 10-13 . 
           [0023]      FIG. 15  illustrates a front perspective view of a food storage container, according to embodiments of the present invention. 
           [0024]      FIG. 16  illustrates a front elevation view of the food storage container of  FIG. 15 , according to embodiments of the present invention. 
           [0025]      FIG. 17  illustrates a front elevation view of a lid and an inner bowl of the food storage container of  FIGS. 15 and 16 , according to embodiments of the present invention. 
           [0026]      FIG. 18  illustrates a bottom perspective view of the lid of  FIGS. 15 to 17 , according to embodiments of the present invention. 
           [0027]      FIG. 19  illustrates a top plan view of the bowl cover of  FIGS. 15 and 16 , according to embodiments of the present invention. 
           [0028]      FIG. 20  illustrates a front and top perspective view of the bowl cover of  FIGS. 15 ,  16 , and  19 , according to embodiments of the present invention. 
           [0029]      FIG. 21  illustrates a front perspective view of a food storage container, according to embodiments of the present invention. 
           [0030]      FIG. 22  illustrates a front elevation view of the lid and inner bowl of the food storage container of  FIG. 21 , according to embodiments of the present invention. 
           [0031]      FIG. 23  illustrates a bottom perspective view of the lid of  FIGS. 21 and 22 , according to embodiments of the present invention. 
           [0032]      FIG. 24  illustrates a front perspective view of a food storage container, according to embodiments of the present invention. 
           [0033]      FIG. 25  illustrates a front elevation view of the food storage container of  FIG. 24 , according to embodiments of the present invention. 
           [0034]      FIG. 26  illustrates a front elevation view of the lid of the food storage container of  FIGS. 24 and 25 , according to embodiments of the present invention. 
           [0035]      FIG. 27  illustrates a bottom perspective view of the lid of  FIGS. 24 to 26 , according to embodiments of the present invention. 
           [0036]      FIG. 28  illustrates a top plan view of the bowl cover of the food storage container of  FIGS. 24 and 25 , according to embodiments of the present invention. 
           [0037]      FIG. 29  illustrates a top perspective view of the bowl cover of  FIG. 28 , according to embodiments of the present invention. 
       
    
    
       [0038]    While the invention is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the invention to the particular embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims. 
       DETAILED DESCRIPTION 
       [0039]    The present invention, according to various embodiments, relates to a composite food storage container that includes an outer polymer container configured to accommodate a glass container within the polymer container.  FIG. 1  is a perspective view of a composite food storage container  10  that includes an outer polymer container  12  and a cover  14 . In some embodiments, the cover  14  includes an annular ring  16  that accommodates sealing structure on the opposite side of the cover  14  (not visible in this illustration) that seals against the inner glass container. 
         [0040]    In some embodiments, the cover  14  has an outer annular ring  18  including a plurality of texture structures  20  that may make it easier for an individual to open and close the cover  14 . The texture structures  20  may extend all the way around the outer annular ring  18 . In some embodiments, the texture structures  20  may be formed as bumps or other-shaped protrusions extending away from the outer annular ring  18 . In some embodiments, the texture structures  20  may be formed as depressions or low spots extending into the outer annular ring  18 . 
         [0041]      FIG. 2  provides a glimpse at the interior of the polymer container  12 , with the cover  14  removed. In the illustrated embodiment, a number of shock-absorbing ribs  22  are disposed on an inner surface  24  of the polymer container  12 . In some embodiments, the polymer container  12  may include from three to about ten or more shock-absorbing ribs  22  radially spaced apart on the inner surface  24 . In some embodiments, the shock-absorbing ribs  22  may be equally spaced apart. In some embodiments, the polymer container  12  may include ten shock-absorbing ribs  22  that are equally spaced about 36 degrees apart. In some embodiments, the shock-absorbing ribs  22  may be integrally molded as part of the polymer container  12 . In some cases, the shock-absorbing ribs  22  may be formed separately and then subsequently adhesively secured to the inner surface  24 . As illustrated in  FIG. 6 , the ribs  22  may extend from the inner surface of the bowl cover  12  in a rotationally symmetrical manner. According to some embodiments of the present invention, the ribs  22  extend from the inner surface of the bowl cover  12  in a manner exhibiting rotational symmetry of order ten; in other words, from the top view of  FIG. 6 , the bowl cover  12  may be rotated about the center through ten different positions and have the same visual appearance in each position. According to other embodiments of the present invention, the bowl cover  12  and ribs, as seen from the top view of  FIG. 6 , may include rotational symmetry of order four, five, six, seven, eight, nine, ten, eleven, or twelve. 
         [0042]    The polymer container  12  includes an upper annular ring  26  that includes structure for releasably securing the cover  14  to the polymer container  12 . In the illustrated embodiment, the upper annular ring  26  includes a pair of locking grooves  28  that are spaced about 180 degrees apart on the upper annular ring  26 . In some embodiments, the upper annular ring  26  may include three or more equally spaced apart locking grooves  28 . Each locking groove  28  includes, as best seen along the left side of  FIG. 2 , an elongate track  30  and an inlet  32 . The cover  14  includes two or more corresponding locking pegs, as will be described with reference to  FIG. 5 . To attach the cover  14  to the polymer container  12 , the cover  14  may be positioned over the polymer container  12  with the locking pegs aligned over the inlets  32 . The cover  14  may be dropped onto the polymer container  12 , with the pegs sliding into the inlets  32 . To secure the cover  14  in place, the cover  14  may be rotated, with the pegs sliding into and along the elongate tracks  30 . 
         [0043]    According to some embodiments, the shock-absorbing ribs  22  are configured to generally match the outer profile of the glass container.  FIG. 3  is a perspective view of an illustrative but non-limiting glass container  50  that may be used as part of the composite food storage container  10 . The glass container  50  includes a curved outer surface  52  that sits on the shock-absorbing ribs  22 . The glass container  52  also includes an upper annular ring  54  that, as will be explained subsequently, cooperates with the aforementioned sealing structure on the underside of the cover  14 . According to various embodiments, the dimensions and profile of the ribs are selected such that the glass container  50  fits snugly (i.e., fits with a slight interference fit), such that the glass container  50  is less likely to slip or fall out of the polymer container  12  during use. 
         [0044]    In some embodiments, the glass container  50  may be removed from the polymer container  12  so that the glass container  50  may be washed (e.g., placed into a dishwasher). In some embodiments, an individual may have two or more glass containers  50  that may be swapped in and out of the polymer container  12 . In this way, an individual may refrigerate or freeze leftovers or other food items in the glass container  50 , and then transfer a particular glass container  50  (containing the desired food) into the polymer container  12  for taking for lunch that day. In some embodiments, the glass container  50  may be a Pyrex® glass bowl having a 2 cup capacity. In other embodiments, the composite food storage container  10  is sized to accommodate smaller or larger glass containers. While the glass container shown in  FIG. 3  includes an outwardly protruding lip, according to other embodiments, the glass container or bowl does not include such a lip. 
         [0045]      FIG. 4  is a cross-sectional view of the composite food storage container  10 , with the glass container  50  removed for clarity.  FIG. 4  illustrates additional features of the polymer container  12  as well as the cover  14 . In some embodiments, the polymer container  12  may be molded as one piece, and may be made of a single polymeric material. In the illustrated embodiment, the polymer container  12  may additional components molded therein to provide desired features such as making it easier to grip the composite food storage container  10 . 
         [0046]    In some embodiments, the polymer container  12  may include a polymer molded body  56  as well as a non-slip bottom  58  that can be secured about the bottom of the polymer molded body  56 . In some embodiments, as illustrated, the non-slip bottom  58  may form the bottom of the polymer container  12 . In some cases, the non-slip bottom  58  may extend at least partially into the shock-absorbing ribs  22 . In some embodiments, the polymer container  12  may include a non-slip handling surface  60  that is molded over the polymer molded body  56 . 
         [0047]    In some embodiments, the non-slip bottom  58  and/or the non-slip handling surface  60  may be formed of any material that provides a good grip. In some embodiments, the non-slip bottom  58  and/or the non-slip handling surface  60  may be formed of silicone. The non-slip bottom  58  and/or the non-slip handling surface  60  may be molded onto the polymer molded body  56 . In some embodiments, the non-slip bottom  58  and/or the non-slip handling surface  60  may be formed by spraying the polymer molded body  56 . In various embodiments, portions of the container  12  are formed from silicone to allow the user to handle the container after heating the container (and its contents) in a microwave. The portions made from silicone will typically have a lower temperature, as silicone more effectively resists temperature increases when subjected to microwave energy. 
         [0048]    In some embodiments, the cover  14  includes an inner sealing ring  62  and an outer sealing ring  64 . The inner sealing ring  62  and the outer sealing ring  64  may be integrally formed with or otherwise attached to the annular ring  16  previously noted. In some embodiments, the inner sealing ring  62  and the outer sealing ring  64  may be configured to sealingly interact with the upper annular ring  54  of the glass container  50 . In some embodiments, part or all of the cover  14  may be formed of a non-slip material such as silicone. For example, in some cases, the texture structures  20  ( FIG. 1 ) may be formed of a non-slip material. 
         [0049]    The polymer container  12  and the cover  14  may be formed of any suitable polymeric material. Illustrative but non-limiting polymeric materials include polyethylene such as HDPE (high density polyethylene) and LDPE (low density polyethylene), polypropylene, and PET (polyethylene teraphthalate). In some embodiments, the polymer container  12  and/or the cover  14  may independently be made of C-PET, polypropylene or polyethylene. In some embodiments, the polymer container  12  and/or the cover  14  may independently be made of silicone. In some embodiments, the polymer container  12  and/or the cover  14  may be injection molded. In some embodiments, the polymer container  12  and/or the cover  14  may include additional materials to impart desired colors or textures to the composite food storage container  10 . In some embodiments, the composite food storage structure  10  may include designs and other artwork for the entertainment of the person using the composite food storage structure  10 . In some embodiments, artwork may be silkscreened onto the polymer container  12  and/or the cover  14 . 
         [0050]      FIG. 5  shows the underside of the cover  14 , illustrating some of the structure previously discussed with reference to other Figures. The cover  14  includes two or more pegs  66 , only one of which is visible in this illustration. In some embodiments, the cover  14  may include two pegs  66  that are spaced about 180 degrees apart. In some embodiments, the cover  14  may, for example, include three pegs  66  that are each spaced about 120 degrees apart, or perhaps four pegs  66  that are each spaced about 90 degrees apart. The number of pegs  66  and their relative alignment will correspond to the number and alignment of the locking grooves  28  formed in the upper annular ring  26  of the polymer container  12 . 
         [0051]      FIG. 6  provides an illustrative but non-limiting example of a possible configuration for the shock-resistant ribs  22 . In this illustration, there are a total of ten shock-resistant ribs  22 , each spaced about 36 degrees apart. The shock-resistant ribs  22  extend from an inner surface  68  and taper down to a lower surface  70 . In some embodiments, the shock-resistant ribs  22  are radially aligned such that the tapered portions are directed towards a common point on the lower surface  70 . In the illustrated embodiment, the shock-resistant ribs  22  are angled away from a common point. 
         [0052]    In seen in  FIG. 2  and  FIG. 6 , the shock-resistant ribs  22  include a first portion  72  located proximate the inner surface  68 , a second portion  74  and a third portion  76 . In some embodiments, as illustrated, the second portion  74  forms an angle of about 165 degrees with the first portion  74 . In some embodiments, the third portion  78  forms an angle of about 165 degrees with the second portion  76 . In some embodiments, the second portion  74  has a length of about 26.1 millimeters and the third portion  78  has a length of about 14.5 millimeters. In some embodiments, the shock-absorbing ribs  22  are about 1.8 millimeters thick. 
         [0053]      FIGS. 7-9  illustrate a container system  100  similar in many ways to container  10 , according to embodiments of the present invention. Container system  100  includes a bowl cover  112 , which may also be referred to as a container or base, and a lid  114 , according to embodiments of the present invention. As shown in  FIG. 8 , the bowl cover  112  may include one or more raised ribs along an inside surface, which are configured to support and a bowl  150 , for example a glass bowl, to thermally separate the bowl  150  from the outer surface of the bowl cover  112 , and to cushion the bowl  150  if the system  100  is dropped or buffeted. Lid  114  is a “peel off” lid, instead of a “screw-on” lid like lid  14 . A lid  114  which can be peeled off of the bowl  150  and base  112  may be easier to use, especially for children with smaller hands and those with disabilities, than a lid  14  which twists, screws, or clicks into place with rotation, according to embodiments of the present invention. One or more tabs  180  included on the lid  114  further facilitate gripping for removal. Lid  114  may be closed onto the bowl cover or base  112  by laying the lid  114  over the base  112  and pushing down onto the lid  114 . 
         [0054]    The lid  114  may include an annular ring  190  which accommodates a sealing structure on the other side of the lid  114 , according to embodiments of the present invention. An example of such a sealing structure is shown in  FIG. 9 . When the lid  114  is inserted over the bowl  150  and base  112 , the lip or rim of the bowl  150  is seated within groove  194 , and inner and outer lips  192  extend on both sides of the lip or rim of the bowl  150 , with a seal being created as the bowl  150  rim is further seated into the groove  194 . At the same time that the bowl  150  rim is being seated in groove  194 , the outer flange of the lid  114  may be seated around the upper rim of the bowl cover  112 , to provide better thermal properties and as a backup seal to the lip/groove  192 / 194  seal, according to embodiments of the present invention. 
         [0055]    The base or bowl cover  112  may be made of silicone, according to embodiments of the present invention. Silicone provides a comfortable, gel-like texture, which may in some cases be described as sticky, to improve a person&#39;s grip on the container system  100  and/or to prevent or discourage sliding of the system  100  with respect to an underlying surface. Silicone also exhibits shock absorbent properties, which improve the cushioning effect of the system  100  with respect to the bowl  150  during a drop or buffet. The lid  114  may also be made out of silicone, according to embodiments of the present invention. According to embodiments of the present invention, the base  112  and/or lid  114  may be made out of an amalgamation or composite of different materials, which may include silicone or be configured to mimic the texture of silicone. Silicone and its derivatives also have desirable thermal properties, such that if the system  100  is microwaved, the base  112  and/or lid  114  are able to be handled even if the bowl  150  has become too hot to touch, according to embodiments of the present invention. 
         [0056]      FIGS. 15 to 20  illustrate an alternative embodiment of a food storage container system  1500 , according to embodiments of the present invention. The container includes a lid  1514  and a bowl cover  1512 , and a bowl  1550 . The food storage container system  1500  operates in much the same fashion, and has characteristics similar to, food storage containers  10  and  100 , according to embodiments of the present invention. Lid  1514  includes an inner perimeter surface  1566  which is shaped and configured to fit snugly over the inner bowl  1550  and to rest against a top outer surface of the inner bowl  1550 , according to embodiments of the present invention. The inner bowl  1550  may be glass, Pyrex®, and/or the like, while the lid  1514  and/or bowl cover  1512  may be silicone, according to embodiments of the present invention. The bottom edge  1564  of the lid  1514  is configured to rest against or otherwise engage with the top edge  1525  of the bowl cover  1512  while the lid  1514  also snugly fits over the inner bowl  1550 , according to embodiments of the present invention. The lid  1514  may also include a tab or overhang  1580  which makes it easier for a user to grip and/or peel away and/or remove the lid  1514  from the inner bowl  1550  and/or the bowl cover  1512 , according to embodiments of the present invention. 
         [0057]    The bowl cover  1512  may be formed integrally as a single piece by an injection molding process, for example. The bowl cover  1512  includes a plurality of ribs  1522  protruding on the inside of the bowl cover  1512 . The plurality of ribs  1522  may each extend from the bottom  1598  of the bowl cover  1512  upwardly toward the upper edge  1525 , for example ribs  1522  may extend a majority of the height, or about three fourths of the height, or the entire height, between the bottom  1598  and the top edge  1525 , according to embodiments of the present invention. From the top view (see  FIG. 19 ), a number of ribs  1522  may protrude from each of the four inner walls  1524  of the bowl cover  1512 , and each of the ribs may be angled with respect to the inner walls  1524  from which they protrude. The ribs  1522  may have a substantially uniform angle with respect to the side walls  1524  along all or most of their height (with height being measured in a direction from a bottom  1598  of the bowl cover  1512  to a top edge  1525  of the bowl cover  1512 ), according to embodiments of the present invention. In other words, the ribs  1522  in some embodiments do not extend from the inside walls  1524  at a perpendicular angle; according to some embodiments of the present invention, each of the ribs  1522  extending from the same wall  1524  extends from the wall  1524  at the same angle. As illustrated in the top view of  FIG. 19 , this angle may be 70 degrees, for example. According to other embodiments, this angle is between 60 and 80 degrees, and according to yet other embodiments, this angle is between 50 and 90 degrees. According to some embodiments of the present invention, the ribs  1522  extend from the inner surface of the bowl cover  1512  in a manner exhibiting rotational symmetry, for example rotational symmetry of order four (due to the square cross sectional shape); in other words, from the top view of  FIG. 19 , the bowl cover  1512  may be rotated about the center through four different positions and have the same visual appearance in each position. 
         [0058]    The bottom  1598  may also include a raised lip  1523 , which may be in the form of a circle as illustrated in  FIGS. 19 and 20 , according to embodiments of the present invention. The raised lip  1523  and the ribs  1522  serve to insulate the inner bowl  1550  from the bowl cover  1512 , and also to separate the inner bowl  1550  from the bowl cover  1512  to better cushion any impacts experienced by the bowl cover  1512 . The raised lip  1523  may also hold the glass inner bowl  1550  by vacuum against the bottom  1598  of the bowl cover  1512 , to ensure that the glass bowl  1550  remains in place against the bottom  1598  even when both are upside down, according to embodiments of the present invention. The raised lip  1523  may be seventy millimeters in diameter, according to embodiments of the present invention. 
         [0059]      FIGS. 21 to 23  illustrate a food storage container system  2100  similar to system  1500 , with a different lid  2114 , according to embodiments of the present invention. Food storage container system  2100  includes lid  2114 , bowl cover  2112 , and inner bowl  2150 , according to embodiments of the present invention. Lid  2114  includes an inner perimeter surface  2166  configured to engage with and seal around a top outer perimeter of inner bowl  2150 , according to embodiments of the present invention. Lid  2114  also includes a lower surface  2164  configured to rest against or otherwise engage with the top edge  1525  of bowl cover  1512  while inner perimeter surface  2166  is engaged with the top outer perimeter of the inner bowl  2150 , according to embodiments of the present invention. Lid  2114  further includes a lower perimeter lip  2165  configured to improve the seal or closure between the lid  2114  and the bowl cover  1512  when the lid  2114  is secured to bowl cover  1512  and inner bowl  2150 , according to embodiments of the present invention. 
         [0060]      FIGS. 24 to 29  illustrates a food storage container system  2400  similar to systems  1500  and  2100 , but with a different lid  2414  and a different bowl cover  2412 , according to embodiments of the present invention. Lid  2414  includes an outer lip  2464  configured to engage with or form a seal with an outer surface  2437  of the upper opening perimeter  2425  of the bowl cover  2412 , according to embodiments of the present invention. Lid  2414  also includes an inner lip  2466  configured to engage with or form a seal with an outer surface of inner bowl  2150 , according to embodiments of the present invention. Lid  2414  further includes a lower perimeter lip  2465  formed on the inner lip  2466  and configured to improve the sealing between the inner lip  2466  and the bowl cover  2412 , according to embodiments of the present invention. 
         [0061]    Because the lid  2414  is configured to cover and seal around an outside of the bowl cover  2412  in which has been placed an inner bowl such as inner bowl  2150 , the bowl cover  2412  may be provided with features to discourage the sides  2424  from bulging outwardly too far upon insertion of the inner bowl  2150 , according to embodiments of the present invention. For example, the bowl cover  2412  may be similar to bowl cover  1512 , with the addition of reinforcement ribs  2433  to each inside corner and a reinforcement base  2435 , which is shown in the shape of a square but which may take other shapes, to the bottom  2498  of the inside of the bowl cover  2412 . Reinforcement ribs  2433  and/or reinforcement base  2435  further stiffen the bowl cover  2412  and discourage warping or bulging out of the sides  2424  upon insertion of the inner bowl  2150 , according to embodiments of the present invention. Otherwise, the ribs  2422  are similar to ribs  1522  described above, and the bottom lip  2423  is similar to bottom lip  1523  described above, according to embodiments of the present invention. Lid  2414  may also include a feature  2480  to facilitate gripping and removal of the lid  2414 , according to embodiments of the present invention. 
         [0062]    Although bowl covers and lids are described herein as being used with a glass inner bowl with a single compartment, the glass inner bowl may also include two or more inner compartments. Also, the shapes of the lids and the bowl covers described herein may be formed to permit the easy stacking of multiple container systems, for example by forming an indentation in the lid which corresponds to a shape of the bottom of the bowl cover or the bottom of the inner glass bowl, according to embodiments of the present invention. Although containers systems described herein may be used to heat foods in a microwave oven, they may also be used to heat foods in a conventional oven, and the same container system may be used in either or both, according to embodiments of the present invention. 
         [0063]    According to embodiments of the present invention, the lid of the container system may include a ventilation hole to let air out of the container, in order to reduce the possibility of excessive moisture (in order to reduce the chance of molding) and over-steaming. Container systems may be used for storage, heating, and transporting foods, and may be manufactured in different shapes, sizes, and/or colors or color combinations. 
         [0064]    Although embodiments of the bowl cover are described as having one or more fins or ribs separating the bowl cover from the inner glass bowl, according to some embodiments of the present invention, these inner ribs are not present. According to such embodiments, a silicone sleeve may be placed directly over the inner glass bowl, with a large (or entire) surface area of contact between the outer surface of the bowl and the inner surface of the bowl cover. Such embodiments may include a very small or an almost imperceptible air gap between the inner bowl and the bowl cover. 
         [0065]    Some embodiments of the present invention may include one or more of the following features and/or characteristics:
       resistance to breaking   extremely heat-resistant   non-slip outer surfaces   minimization of chemical transfer (because glass and silicone are physiologically inert)   reduction in microwaving and/or cooking time   elimination of hot/cold spots in heated food via suspension of the glass bowl   ease of gripping (to reduce risk of dropping or mishandling)   free from staining or odors   highly resistant to thermal expansion (e.g. upon transfer from a refrigeration system to a pre-heated oven).   use for steaming of foods (e.g. by putting water in the outer (e.g. silicone) bowl before placing the glass bowl inside, with steam rising from the channels created by the ribs around the outside of the glass)   vent in the lid to permit escape of steam or moisture or other gases   inner glass bowl is held to the outer bowl cover by the ring (e.g. the 70 mm diameter ring) on the bottom inside of the outer bowl cover, to help ensure that the glass remains in place even when upside down   the lid (e.g. the silicone lid) is completely independent of the bowl cover (e.g. the silicone bowl cover) and either can be in use without the other.       
 
         [0079]    Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. For example, while the embodiments described above refer to particular features, the scope of this invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the claims, together with all equivalents thereof.