Some embodiments provide a multi-layered exothermic microwave cooking apparatus. The apparatus includes an inner cooking plate shell having top and bottom faces. The apparatus also includes an exothermic plastic outer shell to generate heat from microwave radiation. The outer exothermic shell of the vessel has a bottom surface and at least one side wall, and the inner cooking plate shell closes the vessel to create a cooking surface, and to form an inner space between the bottom surface and the plate. The apparatus also includes a safety valve, which is installed on the side wall of the vessel, to release excess pressure from the inner space during microwave cooking.

BACKGROUND

Today, many people use microwave ovens. A person can use one from nearly anywhere (e.g., at home, at work, at the store, etc.). One of the primary reasons for their popularity is because they can conveniently and safely heat food, including beverages. A microwave oven heats food by bombarding it with electromagnetic radiation in the microwave spectrum causing polarized molecules in the food's water content to oscillate back and forth, and thereby generate thermal energy. This microwave cooking process is also known as dielectric heating.

Despite their popularity, microwave ovens or, more specifically, microwave cooking has a number of problems. For instance, microwave cooking can result in food becoming dry, or partially or unevenly heated. In addition, the cooking time can be very long, and the food can lose its original taste after being heated in the microwave oven. The main cause of these problems is due to how the microwave oven heats food through oscillation.

Furthermore, it is commonly advised to avoid placing metal containers in a microwave oven because the electromagnetic waves cannot pass through the metal, unlike glass, plastic, and paper. There is also the possibility that the oscillation of the electromagnetic waves may produce a concentrated electric field at the edge of the metal object. If that edge is in close proximity with another metallic object, sparks may appear between the two objects because of that concentration.

BRIEF SUMMARY

Embodiments described herein a multi-layered exothermic microwave cooking apparatus. The apparatus includes an inner cooking plate shell having top and bottom faces. The apparatus also includes an exothermic plastic outer shell to generate heat from microwave radiation. The outer exothermic shell of the vessel has a bottom surface and at least one side wall, and the inner cooking plate shell closes the vessel to create a cooking surface, and to form an inner space between the bottom surface and the plate.

In some embodiments, the apparatus further includes an exothermic heating plate that is in contact with the bottom face of the cooking plate shell. This exothermic heating plate further generates heat from microwave radiation. In some embodiments, the exothermic heating plate is made by blending Fe2O3, Mn, Zn, and silica powder with alumina (Al203) ceramic. The exothermic heating plate of some embodiments contains fibrous material or is wrapped with fiber, such as glass wool fiber.

The apparatus of some embodiments also has an insulating material in the inner space of the vessel. Different embodiments can use different insulating material. For instance, the insulating material may be an insulation mat. Also, for instance, the insulating material may be quilted material (e.g., such as a heat-retaining thermal panel). The insulation material can be made with ceramic wool fiber.

The apparatus of some embodiments further includes an exothermic plastic lid that is made with the same exothermic plastic as the vessel. This is to further generate heat from microwave radiation.

In some embodiments, the apparatus's inner shell or plate is made with metal (e.g., copper, aluminum). In some embodiments, the plate is made with metal alloy such as carbon steel. In some embodiments, the plate is an exothermic plate that is coated with ceramic to further generate heat from microwave radiation. In some embodiments, the plate is a ceramic plate.

In some embodiment, the apparatus has safety valve so the vessel is not bent out of shape or cracked when vapor pressure in the inner space reaches its threshold limit. In some embodiments, the safety valve includes (1) a metal cap with at least one hole, (2) a head that fits into the cap, (3) a metal spring to push the head against the cap to substantially close the hole, and (4) a metal housing that is coupled with the metal cap to house the head and metal spring. The safety valve may also include (5) a silicone rubber cap or washer that is placed around the hole formed on the inner side wall of the vessel and the metal cap. In some embodiments, the cap has an inner ring that fits into the hole (e.g., from the inner side wall). In some embodiments, the safety valve has a spring-less silicone rubber valve.

In some embodiments, the exothermic plastic is polyphenylene sulfide (PPS) plastic or syndiotactic polystyrene (SPS) plastic mixed with exothermic particles. In some embodiments, the exothermic particles include ferric oxide (Fe2O3) powder mixed with Manganese (Mn) and Zinc (Zn) powder, or copper-nickel-zinc (Cu—Ni—Zn) powder.

In some embodiments, several legs are formed on the outer bottom surface of the vessel.

Some embodiments also provide a multi-layered exothermic microwave cooking apparatus. The apparatus includes a cooking plate having top and bottom faces. The apparatus also includes an exothermic rubber vessel to generate heat from microwave radiation. The vessel has a bottom surface and at least one side wall, and the cooking plate closes the vessel to create a cooking surface, and an inner space between the bottom surface and the plate. The apparatus also includes a safety valve, which is installed on the side wall of the vessel, to release excess pressure from the inner space during microwave cooking.

In some embodiments, the exothermic rubber is silicone rubber mixed with exothermic particles In some embodiments, the exothermic particles includes Fe2O3 powder mixed with Mn and Zn powder, or Cu—Ni—Zn powder.

DETAILED DESCRIPTION

Some embodiments described herein provide a multi-purpose microwave cooking apparatus. The microwave cooking apparatus (also referred to herein as microwave cookware) is multi-purpose in that it can be used to cook food differently. This includes frying, roasting, steaming, and baking.FIG. 1illustrates an exploded view of a microwave cooking apparatus according to some embodiments of the invention.FIG. 1will be described by reference toFIG. 2that shows the different layers of the microwave cooking apparatus.

As shown inFIG. 1, the apparatus100has a vessel105, a lid110, and a heating element115. In some embodiments, the vessel105is metallic, and has a bottom surface120, a side wall125, and an edge130. An open region is defined with the side wall extending from the bottom surface to the outer edge. In some embodiments, at least a portion of the outer side wall is coated with a layer of exothermic coating130to insulate the vessel and generate thermal energy from microwave radiation.

In some embodiments, the cooking apparatus100includes a heating element115adapted to further generate thermal energy from microwave radiation. The heating element115has a top face that is attached to the outer bottom surface of the vessel so as to distribute heat along the bottom of the vessel. In some embodiments, the heating element115is a mixture of elastic material and ferrite particles. In some embodiments, the heating element115is ferrite rubber. The ferrite rubber can potentially provide exothermic heat at least up to 280° Celsius (C). In some embodiments, several legs155are formed on a bottom face of the elastic material to raise the vessel in order to prevent rapid heat loss. Additional details relating to such a heating element will be described below by reference toFIGS. 13-16.

In some embodiments, at least a portion of the outer side wall125of the vessel is coated with a layer of exothermic coating130. In some embodiments, the outer bottom surface120of the vessel is also coated with the exothermic coating. The exothermic coating130of some embodiments is an exothermic glaze having ferrite, silicon (Si), and aluminum (Al) particles. In some embodiments, the exothermic materials include ferrite powder, Mn, Zn, silicon oxide (SiO2), Si, and aluminum oxide (Al2O3). In some embodiments, the exothermic coating is an exothermic glaze having a mixed metal powder compound (e.g., Fe2O3) with ferrosilicon (Fe—Si) powder, aluminum silicate powder, and ethylene glycol.

Instead of the exothermic glaze, the vessel105of some embodiments is coated with a ceramic coat. The ceramic coat of some embodiments is a mixture of ceramic powder and exothermic particles. In some embodiments, the exothermic particles include ferrite powder. In some embodiments, the exothermic particles also includes manganese zinc (MnZn) powder, magnesium copper zinc (MgCuZn) powder, and nickel zinc (NiZn) powder. As mentioned above, the exothermic materials include ferrite powder, Mn, Zn, silicon oxide (SiO2), Si, and aluminum oxide (Al2O3). In some embodiments, the exothermic particles include Fe2O3 powder with Manganese (Mn) and Zinc (Zn) powder, or copper-nickel-zinc (Cu—Ni—Zn) powder for electro-microwave absorption.

FIG. 2shows the different layers of the vessel of the microwave cooking apparatus ofFIG. 1. As shown, the vessel includes a metallic body205. In some embodiments, the vessel is formed using aluminum, stainless steel, copper, carbon steel, and/or clad metal. In some embodiments, the inner area is coated with a layer of non-stick coating210. Specifically, the inner bottom surface and the inner side wall are coated with the non-stick coat210. As stated above, the metallic body205may be coated with an exothermic glaze130or a ceramic coat.

Referring toFIG. 1, the cooking apparatus100includes a lid110. The lid has a handle135to handle the lid. A person can use the handle to place the lid over the vessel or remove it from the vessel. At least one vent hole140is formed on the lid to allow heated moisture to escape the vessel without disengaging the lid from the vessel. In some embodiments, the handle135is wrapped with a protective member150to make the handle safe to touch when the vessel105is heated. In some embodiments, the protective member is made of silicone rubber.

In some embodiments, the lid110has a metal disk160made of metal to reflect microwave radiation. This is to prevent food being cooked with microwaves. In some embodiments, the metal is stainless steel. The metal disk can be carbon steel, aluminum, stainless steel, copper, and/or clad metal. As shown, the metal disk can be dome-shaped.

In some embodiments, the lid is coated with the exothermic glaze or ceramic coat. By coating the lid, the microwavable cookware of some embodiments generates heat from all sides. For example, the coat on the lid and vessel generate thermal energy from microwave radiation. Similar to a gas or electric oven, the cookware can cook a food item from all sides.

The lid110has an elastic ring145to fit into the vessel to substantially seal the container. The elastic ring145is attached to the outer edge of the metal disk and sits between the metal disk and the vessel when the lid is placed over the vessel. This is so that the metal disk does not make contact with the vessel, and that there is a predetermined amount of space between the outer edges of metal disk and the vessel in order to prevent arcing or sparks from appearing between the outer edges of the lid and the vessel. In some embodiments, the elastic ring145is a silicone rubber ring.

The elastic ring can be coupled to the lid in various different ways. For instance, the elastic ring can be glued to the lid. Alternatively, the lid may be shaped to hold the elastic ring.

In some embodiments, the cooking apparatus has a see-through, or a look and cook lid adapted to cover the vessel.FIG. 3illustrates a see-through lid305of the microwave cooking apparatus300according to some embodiments. The see-through lid305of some embodiments has a glass disk310that is surrounded by a non-metallic rim315. The glass may be tempered glass. The figure also shows a vessel345. Attached to the vessel is the heating element365that is described above by reference toFIG. 1.

The glass disk310may be dome-shaped. In the example ofFIG. 3, the glass disk is slightly dome-shaped, which makes the apparatus300ideal for frying food with a microwave oven. At least one vent hole320is formed on the lid305to allow heated moisture to escape the open area of the vessel345without disengaging the lid from the vessel. In the illustrated example, only one vent hole320is formed on the glass disk. A metal ring360is placed in the vent hole in order to protect the glass disk310.

In some embodiments, the lid305has a handle330to place the lid on the container (i.e., vessel) or remove the lid from container. As shown inFIG. 3, a hole is formed on the center of the glass disk310, and a coupling member340is inserted in the hole to couple the glass disk to the handle330. The handle330is wrapped with a protective member345to make the handle safe to touch when the vessel is heated. In some embodiments, the protective member345is a piece of silicone rubber that wraps around the handle portion of the handle330. The handle portion being the surface area that a person can pick up when the vessel is heated.

The non-metallic rim315includes an elastic ring325that fits into the vessel345and sits on the edge350of the vessel to substantially seal the container. In some embodiments, the non-metallic rim315is a silicone rim, and the elastic ring is a silicone ring formed on the silicone rim. In some embodiments, the silicone rim and ring are just one piece of silicone rubber that is shaped to hold the glass disk. For instance, the silicone rim can have an open space to insert the glass therein.

In the example ofFIG. 3, the non-metallic rim315serves multiple purposes. First, the non-metallic rim315supports and protects the glass disk310. Second, the non-metallic rim315is used to prevent sparks from appearing between edges of two metal pieces when the microwave is turned on with the apparatus300in it.

In some embodiments, the lid's silicone rubber is mixed with exothermic particles. This is to allow the lid to generate heat from microwave radiation. Instead of silicone rubber, the cookware of some embodiments has a heat resistant plastic lid. For instance, the silicone rim can be made with polyphenylene sulfide (PPS) or syndiotactic polystyrene (SPS) plastic. Like the silicone rubber, the PPS or SPS plastic may be mixed with exothermic particles to generate heat from electromagnetic waves.

In some embodiments, the vessel345has an upper outer edge355and a lower inner edge350. In some embodiments, the non-metallic rim315has a size (e.g., diameter, radius, and circumference) that allows the rim to fit into the vessel345. This is so that the silicone ring325sits on the lower inner edge350.

In some embodiments, the cooking apparatus has a metal roaster lid and a steamer insert.FIG. 4illustrates a metallic lid405and a steamer insert410of the microwave cooking apparatus400according to some embodiments. The figure also shows a vessel415that is similar to the one described above by reference toFIG. 1. Attached to the vessel415is a heating element465that is described above by reference toFIG. 1.

As shown inFIG. 4, the cooking apparatus of has a lid405that is formed to cover the vessel. The lid405is made with a metal disk435. The metal disk can shield a food item by reflecting microwaves. In other words, the metal disk prevents the food item being cooked with the microwaves. In some embodiments, the metal is stainless steel. The metal disk435can be carbon steel, aluminum, stainless steel, and/or copper.

The metal disk435is coupled to an elastic ring425. The elastic ring425is attached to the outer edge445of the metal disk435. The elastic ring425sits between the metal disk and the vessel415when the lid405is placed over the vessel. This is so that the outer edge445of the metal disk435does not make contact with the vessel. Also, there is a predetermined amount of space between the outer edges of metal disk and the vessel. These are all features of the lid to prevent arcing or sparks from appearing between the outer edges of the lid and the vessel.

In some embodiments, the cookware uses a non-metallic disk. In some embodiments, the lid is made primarily with polyphenylene sulfide (PPS) plastic. In some embodiments, the lid is made of plastic engineered with syndiotactic polystyrene (SPS) resin. In some embodiments, the lid has a silicone rubber disk.

The silicone rubber, PPS plastic, or SPS plastic may be mixed with exothermic particles. For instance, the disk may be made by mixing PPS polymer with exothermic particles. In some embodiments, the exothermic particles include ferric oxide (Fe2O3) powder with Manganese (Mn) and Zinc (Zn) powder, or copper-nickel-zinc (Cu—Ni—Zn) powder. The exothermic particles are for electro-microwave absorption to generate heat.

In some embodiments, the cookware has a lid that is coated with an exothermic glaze or an exothermic ceramic coat. For instance the lid may be coated with a ceramic coat that is blended with exothermic particles (e.g., Fe2O3, and Mn and Zn powder, or Cu—Ni—Zn powder). As another example, the lid may be coated with an exothermic glaze having a mixed metal powder compound (e.g., Fe2O3) with ferrosilicon (Fe—Si) powder, aluminum silicate powder, and ethylene glycol.

In some embodiments, the cookware's lid405is dome-shaped. In the example ofFIG. 4, the dome is a high-dome or is shaped to have a predetermined height. This allows the apparatus to be used for roasting purposes. For example, the cookware shown in the figure can be used to roasting purposes (e.g., roasting poultry). Thermal energy is generated from the heating element465and the outer coat470being exposed to microwave radiation. The energy is then transferred to the inner areas of the body of the vessel. As indicated above, the lid may also generate heat from microwave radiation.

As shown, at least one vent hole420is formed on the lid405to allow heated moisture to escape the open region of the vessel415without disengaging the lid from the vessel. In the example ofFIG. 4, six vent holes are placed on the side of the dome-shaped lid. The lid405also has a handle430. A hole is formed on the center of the metal disk435, and a coupling member (not shown) is inserted in the hole to couple the handle430to the metal disk. The coupling member can be a screw. If there is a screw, there can also be a washer so that the handle430does not easily unscrew. In some embodiments, a surrounding area475where the handle430is coupled to the plate435can be depressed. This is mainly done to save space (e.g., for the cookware to fit into a small microwave oven).

In some embodiments, the microwave cookware further includes a steamer insert to steam food items. In some embodiments, the steamer insert is made of metal. The metal can be aluminum, stainless steel, copper, carbon steel, and/or clad metal. Alternatively, the steamer insert can be made of plastic. In the example ofFIG. 4, the steamer insert includes a number of steam holes. Different sections of the steamer can be raised or lowered to allow steam to flow different directions and/or provide places for food (e.g., vegetables) to sit.

In some embodiments, the vessel has an upper outer edge455and a lower inner edge450. In some embodiments, the lid405sits over the upper outer edge455of the vessel415, and the steamer insert410sits on lower inner edge450of the vessel. In the example cookware400ofFIG. 4, the elastic ring425of the lid405sits on the outer edge455, and the outer edge475of the steamer insert410sits on the lower inner edge450of the vessel415.

In some embodiments, the microwave cooking apparatus has a lid that is coated with an exothermic glaze or a ceramic coat. The coating on the lid further insulates the vessel and generates heat from microwave radiation. In some embodiments, the coating on the lid further provides an upper heat generation layer. This is particularly useful in cases where the cookware is used for baking purposes as heat is coming from all directions of the vessel.

FIG. 5illustrates a lid505of the microwave cooking apparatus500according to some embodiments of the invention. The figure also illustrates a vessel525(i.e., container) that is similar to the one described above by reference toFIG. 1. Attached to the vessel525is a heating element530that is the same as the one described above by reference toFIG. 1.

As shown inFIG. 5, the lid505has a plate520that is coated with an exothermic glaze510or a ceramic coating. In some embodiments, the lid is coated with an exothermic ceramic coat having exothermic particles. In some embodiments, the exothermic particles have ceramic powder and ferrite. In some embodiments, the exothermic particles also has manganese zinc (MnZn) powder, magnesium copper zinc (MgCuZn) powder, and nickel zinc (NiZn) powder. In some embodiments, the exothermic particles include Fe2O3 powder with Manganese (Mn) and Zinc (Zn) powder, or copper-nickel-zinc (Cu—Ni—Zn) powder for electro-microwave absorption.

In some embodiments, the lid is coated with an exothermic glaze. The glaze of the cookware of some embodiments is a mixed metal alloy powder compound comprising ferrite, silicon (Si), and aluminum (Al). In some embodiments, the exothermic glaze includes a mixed metal powder compound (e.g., Fe2O3) with ferrosilicon (Fe—Si) powder, aluminum silicate powder, and ethylene glycol.

In some embodiments, the microwave cooking apparatus has double wall structure.FIG. 6illustrates a double walled vessel600of the microwave cooking apparatus according to some embodiments. The inner shell605is disposed adjacent the outer shell610and the edges of the shells are (e.g., hermetically) sealed to form a cavity615(also referred to herein as inner space, a thermal dynamic layer, inner chamber) between the two shells. In some embodiments, the cavity615is filled at least partially with a thermal conductive medium645to form a thermodynamic layer that can absorb and retain heat for an extended period time. In some embodiments, the inner or outer shell is made using at least one of aluminum, stainless steel, carbon steel, copper, and clad metal. The double walled vessel600of some embodiments can heat up to about 450° Celsius (C) with a microwave oven.

Different embodiments can use different thermal conductive mediums. In some embodiments, the microwave cookware uses a gaseous medium, such as ambient air. In some embodiments, the inner space is at least partially filled with a compound, such as silicone oil.

In some embodiments, the inner space is at least partially filled with a fibrous medium, such as carbon fiber. The inner space may have a piece of fiberglass woven fabric for insulation. The fiberglass woven fabric may have a honeycomb form. For instance, the fabric can have a number of cells that are similar in appearance to those of a bee's honeycomb. The honeycomb fiberglass fabric may be used because it is lightweight, fire resistant, flexible, and has good impact resistance.

In some embodiments, the fibrous medium includes ceramic wool fiber for insulation. In some embodiments, the inner space has a piece of material made with ceramic fiber. In some embodiments, the inner space the material is a ceramic fiber blanket or mat. The blanket is a lightweight, thermally efficient ceramic fiber insulating material that has dimensional stability at high temperature. In some embodiments, the blanket is made from high-purity alumina, zirconia, and silica spun ceramic fibers. In some embodiments, the blanket has a temperature grade around or above 760° Celsius (C).

In some embodiments, the fibrous medium includes glass cloth.

In some embodiments, the inner space615includes a quilted panel. The panel may be made using glass cloth. The panel may be sewn into a pillow-like shape and filled with silica powder mixture. The panel may be sewn first closed and then compressed. The sewing technique allows the panel to be flexible. For instance, the quilted panel can be wrapped around the outer side wall of the inner shell of the double-walled vessel. The panel can also withstand abuse that the cookware is subject. That is, the panel is resistant to various vibration and motion of the vessel. Depending on the size of the inner chamber, the thicknesses of the panel may change.

In some embodiments, inner space615contains a thin sheet of micro-porous insulation material. The thin sheet may be made with a micro-porous board material. As the board can be delicate, it might be coated in some manner to reinforce the board material. The thin sheet may be made primarily with pyrogenic silica. The thin sheet may be reinforced in some manner (e.g., with e-glass filament, oxide opacifier, etc.).

In some embodiments, the inner space615includes a piece of foam to keep food items hot for several hours. In some embodiments, the foam is made of polyurethane. In some embodiments, the inner space is at least partially filled with a chemical gel. In some embodiments, the chemical gel includes ammonium nitrate, calcium chloride, sodium chloride, sodium acetate, and ammonium chloride. One of the benefits of using such a gel is for its endothermic performance or its ability to absorb heat. That is, the gel can be used to keep food cold for an extended period of time.

As shown inFIG. 6, the inner space may be fully filled with the thermal conductive medium. As a first example, the inner space may be filled with the above-mentioned fibrous medium. As another example, the inner space may be filled with the thin sheet of microporous material.

In some embodiments, the inner space is at least partially filled with a set of one or more thermal conductive pads. The inner space can be filled at least partially with a thermal conductive gel. For faster heat absorption and transfer, the inner space may include a silicone-based material that is mixed with an aluminum oxide compound. In some embodiments, the inner space is at least partially filled with a silicone rubber having ferrite particles (e.g., manganese zinc (MnZn) ferrite particles).

In some embodiments, the cookware600has pressure relief valve installed on the outer shell. This is to relive pressure built up in the cavity615between the inner and outer shells605and610.

In some embodiments, the microwave cooking apparatus600has an exothermic plate620. The exothermic plate620generates and transfers heat. In some embodiments, the exothermic plate620is placed in the cavity between the inner and outer shells. In particular, the plate is placed between the outer bottom surface of the inner shell and the inner bottom surface of the outer shell. In some embodiments, the plate makes contact with both shells to transfer heat to both shells. In some embodiments, the outer shell610has an opening (e.g., an open circle) to expose the plate620to microwave radiation.

In some embodiments, the exothermic plate620is formed with exothermic clay ceramic. In some embodiments, the ceramic clay has ferrite powder. In some embodiments, the plate has clay ceramic powder mixed with iron oxide powder (Fe2O3) powder and magnesium-Zinc (Mn—Zn) silicate powder. In some embodiments, the plate is made with clay ceramic powder mixed with iron (III) oxide powder (Fe2O3) powder and copper-nickel-zinc (Cu—Ni—Zn) powder for electro-microwave absorption. In some embodiments, the clay ceramic includes at least one of manganese zinc (MnZn) powder, magnesium copper zinc (MgCuZn) powder, and nickel zinc (NiZn) powder. Instead of Fe2O3, some embodiments use Fe3O4 (iron (II,III) oxide) powder. In some embodiments, the plate is made of ferrite silicone mixture and Fe3O4 powder.

FIG. 6also shows a heating element625according to some embodiments of the invention. The heating element625is similar to the one described above by reference toFIG. 1. However, inFIG. 6, the heating element625includes a number of vent holes630. A set of one or more vent holes630can be formed on the elastic heating element to prevent disfigurement of the heating element. Also, when there is an opening along the bottom of the outer shell, heated air or moisture can come out of the cavity through the vent holes.

Further, as shown inFIG. 6, the heating element625may be supported or raised by a number of supporting members640or legs. In some embodiments, the supporting members640are formed on the bottom of the heating element.

In some embodiments, the cookware's vessel is covered at least partially with a thermal exothermic layer635. In some embodiments, the layer serves multiple purposes. The layer may insulate the vessel by trapping heat. The layer may make the vessel safe to touch when heated. Different embodiments use different materials for the outer layer. In some embodiments, the outer layer has heat resistance up to and excess of 260° C. In some embodiments, the layer is composed of polystyrene such as syndiotactic polystyrene (SPS) plastic. In some embodiments, the layer is composed of a polymer such as polyphenylene sulfide (PPS) plastic. In some embodiments, the layer is made using silicone rubber. To enhance the exothermic properties of the vessel, the PPS, SPS, or silicone rubber may be mixed with exothermic particles.

In some embodiments, the cookware's outer shell is coated with an exothermic glaze or exothermic ceramic coat. The glaze or coat may be covered over with PPS or SPS plastic. The glaze or coat may be covered with a piece of silicone rubber. The PPS plastic, SPS plastic, or silicone rubber material may be mixed with exothermic particles for additional exothermic performance.

In some embodiments, the inner space of the multi-layered container600is at least partially filled with a reactive medium or material that absorbs one or more different gaseous mediums, such as the ambient air mentioned above, and holds the gaseous mediums for an extended period of time. This is to improve and maintain a vacuum inside the sealed inner space. The reactive material of some embodiments can absorb different types of gas molecules, such as H2O, O2, N2, CO, CO2, etc.

When a gaseous medium makes contact with the reactive material, the gaseous medium is combined with the reactive material through a chemical reaction. The reactive material essentially absorbs or eliminates even small amounts of gas molecules from the inner space. In some embodiments, the reactive material is getter that can absorb heated air and retain it for several hours. In some embodiments, a deposit of getter material is placed in the inner space of the multi-layered container. In some embodiments, the getter comprises zirconium (Zr). In some embodiments, the getter is primarily zirconium-based in amount or volume but can include one or more other elements, e.g., aluminum (Al), cobalt (Co), iron (Fe), etc.

In some embodiments, the reactive material is injected or placed in the inner chamber of the multi-layer container with one or more of the thermal conductive material listed above.FIG. 7illustrates a container of the microwave cooking apparatus according to some embodiments. Specially, the figure shows a thermodynamic layer715that has getter765. In the illustrated example, the microwave cooking container700is a thermal microwave cooking vessel in that it can retain heat for an extended period of time.

When the multi-layered container700is heated, the air within the thermodynamic layer715is heated, and the air molecules are absorbed by getter765. The getter765can retain the heated air for several hours, similar to a thermal flask. For instance, when getter765is placed in the thermodynamic layer with ambient air, the multi-layered container may remain heated for about 5 to 6 hours. In some embodiments, the inner space has getter and ambient air. In some embodiments, the inner space has getter and silicone oil. In some embodiments, the inner space has getter and a fibrous medium (e.g., ceramic wool). In some embodiments, the inner space715has getter765and one or more other thermal conductive mediums described above by reference toFIG. 6.

In some embodiments, the thermal microwave cooking vessel700has a set of one or more support structures720and735. In some embodiments, a support structure (720or735) is made with a piece of silicone rubber. The support structures720and735prevent the disfigurement of the inner and outer shells. Therefore, they protect the integrity of the thermal dynamic layer715. Each support structures can include a surface area (725or755) that is supported by a bottom support member (730or745). In some embodiments, the cookware includes a round support structure720that fits around the inner shell705. The surface area725730may be in contact with the outer side wall of the inner shell705. The support member730may be in contact with the inner side wall of the outer shell710.

In some embodiments, the cookware700includes a plate-like support structure735that is disposed in between the outer bottom surface of the inner shell705and the inner bottom surface of the outer shell710. The top755of the support plate735may make contact with the outer bottom surface of the inner shell705. One or more bottom support members745may be formed on the plate735. The bottom support member745may touch the inner bottom surface of the outer shell710.

In some embodiments, the cookware's inner shell705is covered at least partially with an exothermic glaze770or a ceramic coat that is described above by referenceFIGS. 1 and 2. In the example ofFIG. 7, the outer bottom surface and the outer side wall of the inner shell705is coated with the exothermic glaze770. In some embodiments that coat the inner shell705, there can be an open region in the outer shell710. The opening exposes the exothermic glaze770to microwave radiation. In some embodiments, the opening is a round circle along the bottom surface of the outer shell710.

As indicated above, in some embodiments, the cookware's outer shell710is covered at least partially with a thermal exothermic layer760. The exothermic layer760is described above by reference toFIG. 6. Finally, in the example ofFIG. 7, a number of legs750are attached to the double walled container700.

In some embodiments, the cookware's thermal dynamic layer has a piece of ferrite rubber to insulate the vessel.FIG. 8illustrates a double walled vessel800of the microwave cooking apparatus with such a thermal dynamic layer850. As shown, the inner shell805is disposed adjacent the outer shell810, and the edges of the shells are (e.g., hermetically) sealed to form the thermal dynamic layer850between the two shells. In some embodiments, the inner or outer shell is made using at least one of aluminum, stainless steel, carbon steel, copper, and clad metal.

In some embodiments, the cavity850is filled at least partially with a thermal conductive medium to form a thermodynamic layer that can absorb and retain heat for an extended period time. As mentioned above, different embodiments can use different thermal conductive mediums. In the example ofFIG. 8, to absorb and transfer heat, the thermodynamic layer850includes a piece of ferrite rubber820and a piece of fibrous material825. The ferrite rubber may be attached (e.g., glued) to the surface of one of the two shells (805or810). For instance, the piece of ferrite rubber820is attached to the outer surface of the inner shell805. The rubber820may wrap around the inner shell805as illustrated in the figure.

In some embodiments, the rubber820is attached to the outer side wall and/or the outer bottom surface of the inner shell805. In conjunction with the inner shell or instead of it, a piece of ferrite rubber may be attached to the inner surface of the cookware's outer shell810. In some embodiments, instead of ferrite rubber, the cookware uses a different material (e.g., PPS or SPS with exothermic particles). In some embodiments, the cookware uses silicone rubber with exothermic particles.

In some embodiments, the inner chamber850includes multiple layers of different materials. For instance, in the example ofFIG. 8, the cavity850includes a layer of ferrite rubber820and a layer of fibrous material825. In some embodiments, the fibrous material825is ceramic wool or fiberglass wool to increase thermal conductivity for about 4-5 hours. One of the reasons for using such wool is because of its ability to remain stable in a high-temperature setting. Also, the wool is used because of its thermal insulation performance. In some embodiments, the inner chamber850has a piece of foam to keep food items hot for several hours. In some embodiments, the foam is made of polyurethane.

As mentioned above, in some embodiments, the inner chamber includes a fibrous medium, such as ceramic wool. In some embodiments, the inner chamber850includes a quilted panel or a thin bendable board made of microporous material. In some embodiments, the thermal conductive medium825may be attached in some manner to the ferrite rubber825. As illustrated, there may be a space or an area855in the inner chamber850to hold a pocket of air. The air may act as a third insulating member in addition to the rubber820and the medium825. The space also allows the materials820and825to expand when the vessel is heated. In some embodiments, the thermal conductive medium825(e.g., the quilted panel, the thin sheet) may fill out the remaining area next to the ferrite rubber825.

In some embodiments, the inner chamber850is at least partially filled with a chemical gel. In some embodiments, the chemical gel includes ammonium nitrate, calcium chloride, sodium chloride, sodium acetate, and ammonium chloride. One of the benefits of using such a gel is for its endothermic performance or its ability to absorb heat. That is, the gel can be used to keep food cold for an extended period of time.

In some embodiments, the cookware's outer shell810is covered with a layer of material to insulate the vessel and to make the vessel safe to handle. In the example ofFIG. 8, the outer surface and the handle area of the outer shell810are covered with layers of heat insulating materials. Specifically, the figure shows an outer cover835and a set of cool touch handles840that insulate the vessel and make it safe to touch. In some embodiments, the thermal insulating member (835or840) is made of a polymer such as polyphenylene sulfide (PPS). In some embodiments, the thermal insulating member (835or840) is made with PPS plastic. In some embodiments, the thermal insulating member is made of silicone rubber. In some embodiments, the PPS plastic, SPS, or silicone rubber may be exothermic in that it was mixed with exothermic particles. In some embodiments, the outer cover835has exothermic particles while the handle840does not have such particles.

In the example ofFIG. 8, the outer cover835covers the outer surface of the outer shell815. For instance, the outer side wall and the outer bottom surface of the outer shell are surrounded by the cover layer835. As will be described below by reference toFIG. 9, the cover layer may only cover the bottom portion of the outer shell.

In some embodiments, the microwave cooking apparatus800has an exothermic plate830. In some embodiments, the exothermic plate830is a ceramic plate. Alternatively, the exothermic plate can be a clay plate (e.g., clay ceramic plate). For exothermic performance, the clay plate may be blended with ferrite (Fe) powder, and manganese (Mn) and zinc (Zn) silicate powder.

Finally, as shown inFIG. 8, the cookware800of some embodiments has a pressure release valve845. There is a hole in the outer shell810. The valve845covers that hole and lets out excess pressure built up within the inner chamber850of the doubled walled vessel.

FIG. 9illustrates yet another example of a microwave cooking apparatus900according to some embodiments of the invention. This figure is similar to the previous figure. Different from the previous figure, the current figure shows that at least a portion of the cookware's outer surface of the inner shell910is coated with an exothermic powder coat920and at least a portion of the outer surface of the outer shell is coated with a ceramic coat915. Each coating (910or915) may include Fe, Mn, and Zn as exothermic particles.

Also different from the previous figure,FIG. 9shows that only the outer bottom surface of the cookware900and the handle area can be covered with layers of heat insulating materials. The previous figure showed that the entire side wall can be covered with the cover layer935. For instance, if some type of plastic is used, it may only cover the outer bottom surface and/or the handle area.

Further, different from the previous figure, the thermal conductive medium925(e.g., the quilted panel, the thin sheet) fills out the remaining area next to the ferrite rubber925. Further, different from the previous figure,FIG. 9shows that the cookware900of some embodiments has an outer bottom cover935with a number of vent holes955. The outer bottom cover may be made from PPS plastic. PPS plastic is used because it has high heat resistance. The PPS may be exothermic in that it is mixed with exothermic particles. In some embodiments, the outer bottom cover is made with silicone rubber.

Similar to the previous figure,FIG. 9shows that the inner chamber of the vessel can include a piece of fibrous material920. Further, the cookware900can have a set of one or more cool touch handles (e.g., made of silicone rubber that wraps around the outer surface of the outer shell910). In addition, the cookware can have a safety valve945to relieve excess pressure within the inner chamber950.

FIG. 10illustrates yet another example of a microwave cooking apparatus1000according to some embodiments of the invention. This figure is similar to the previous figure. The main differences between the current figure and the previous figure are that the cookware1000shown in the current figure is footed. That is, a set of one or more bottom support members1035is attached to or formed on the outer bottom surface of the outer shell. Also, the cookware ofFIG. 10does not have the set of cool touch handles940.

FIG. 11illustrates yet another example of a microwave cooking apparatus1100according to some embodiments of the invention. As shown, the cookware's inner shell1105is wrapped with a piece of ferrite rubber1120. The rubber may1120be attached to a portion of the outer surface of the inner shell1105. The cookware1100also has a piece of fibrous material1125(e.g., ceramic wool fiber, fiberglass woven fabric, etc.) for added insulation. The outer surface of the cookware is also coated with an exothermic ceramic coat. In the example ofFIG. 11, the coating1115is on the outer surfaces of the lid1135and outer shell1110.FIG. 11also shows that the cookware1100of some embodiments has a pressure release valve1145and an exothermic ceramic or clay ceramic plate1130.

In some embodiments, the cookware includes an exothermic infrared cover that generates and traps heat.FIG. 12shows such an exothermic infrared cover1200according to some embodiments of the invention. As shown, the cover1200includes at least one exothermic layer1215. In some embodiments, the exothermic layer1215has a layer of ferrite rubber. The rubber may be coated on or attached to the outer surface of the plate1205of the cover1200. In some embodiments, the exothermic layer1210is an exothermic ceramic coat.

In some embodiments, the cover1200includes a heat-resistant outer layer1215(e.g., thermal insulation layer). The heat-resistant outer layer1215may cover the exothermic layer1210. In some embodiments, the heat-resistant outer layer1215serves multiple purposes. The heat-resistant outer layer may insulate the vessel by trapping heat. The heat-resistant outer layer1215may make the cover1200safe to touch when heated. Different embodiments use different materials for the heat-resistant outer layer. In some embodiments, the heat-resistant layer is composed of polystyrene such as syndiotactic polystyrene (SPS). In some embodiments, the heat-resistant layer is composed of a polymer such polyphenylene sulfide (PPS). The vessel of some embodiments uses such a polystyrene or polymer because it has heat resistance up to and excess of 260° C.

In some embodiments, the lid has a disk1205made of PPS plastic. In some embodiments, the lid has a disk made with SPS plastic. In some embodiments, the lid has a disk made with silicone rubber. The PPS plastic, SPS plastic, or silicone rubber may be mixed with exothermic particles.

In some embodiments, the exothermic particles include Fe2O3 powder with Manganese (Mn) and Zinc (Zn) powder, or copper-nickel-zinc (Cu—Ni—Zn) powder for electro-microwave absorption. In some embodiments, the lid has a metal disk made of stainless steel, aluminum, or carbon steel.

As mentioned above, the multi-purpose microwave cookware of some embodiments has an elastic heating element.FIG. 13illustrates a heating element1300of the microwave cooking apparatus according to some embodiments. The heating element1300has a top face and a bottom face, and the top face attached to the outer bottom surface of the microwaveable vessel. In some embodiments, the heating element1300is attached to the outer bottom surface by a heat press process. The heat press process can include the following steps: applying a layer of adhesive to the outer bottom surface of the vessel, drying the vessel for about an hour in an area having a temperature about 180° C. and pressing the heating element onto vessel at temperatures ranging between 150-250° C. This heat-press process removes excess water, minimizes shrinkage, and ensures greater resistance to high temperature, moisture, and physical abuse.

In some embodiments, the heating element1300is ferrite rubber, which is a mixture of ferrite particles having the general chemical formula MOFe2O3, where MO is one or more divalent metal oxides combined with 48 to 60 mole percent of iron oxide, and elastic material. In some embodiments, the elastic material is silicon rubber capable of withstanding temperatures up to at least the transitional temperature of the ferrite particles, which is temperature marking the change of the particles from a ferromagnetic to paramagnetic state. In some embodiments, the elastic material is silicon rubber capable of withstanding at least 260° Celsius (C).

The use of ferrite rubber as a heating element1300offers several advantages over coating a vessel with ferrite particles. First, it is durable in that it is flexible and strong enough to be used in demanding conditions such as in a microwave oven or in a sink. It is also durable in that it protects the magnetic properties of the ferrite particles by being moisture resistant. Secondly, it is moldable in that it can be molded into varying shape or size. For example, in some embodiment, several legs are molded or formed on the bottom face of the heating element1300. This eliminates the manufacturing steps of separately attaching the legs onto the bottom face of the heating element.

FIG. 14illustrates a bottom plan view of the heating element ofFIG. 13. Provided on the bottom face1400of the heating element1400is a plurality of thermal insulating members1405or legs. In some embodiments, at least four legs are geometrically arranged or formed on the bottom face of the heating element1400to provide support for the vessel1410. The thermal insulating members1405are narrow-shaped so as to make minimal contact with the inner surface or turntable of the microwave oven, and thus provide insulation to the vessel by ensuring that the thermal energy stored in the heating element800is not rapidly transferred to the inner surface of the microwave oven.

FIG. 15shows the results of an exothermic test performed on a microwave vessel with a piece of ferrite rubber. Specifically, this figure shows an exothermic test for a pan that has a diameter of 55 mm. The ferrite rubber is the primary heating element for the test. The test was performed with a 1000 Watt (W) microwave oven. The results show the temperature in degrees Celsius (C).

As shown inFIG. 15, the results include four sets of data. The first set of data has temperature measurements after heating the vessel for just 1 minute with the microwave oven. The average temperature was measured at 196.9° C. The high temperature was measured at 2267° C. The high was based on a temperature reading from the center of the pan. The low temperature was measured at 177.7° C. The low was based on a temperature reading from the outer edge of the pan. The first set of data also includes a graphical representation of the pan with the temperature reading of the different areas around the pan.

The second set of data has temperature measurements after heating the vessel for 3 minutes with the microwave oven. The average temperature was measured at 258.2° C. The high temperature was measured at 278.5° C. The high was based on a temperature reading from the center of the pan. The low temperature was measured at 254.3° C. The low was based on a temperature reading from the outer edge of the pan. The second set of data also includes a graphical representation of the pan with the temperature reading of the different areas around the pan.

The third set of data has temperature measurements after heating the vessel for 5 minutes with the microwave oven. The average temperature was measured at 268.1° C. The high temperature was measured at 287.5° C. The high was based on a temperature reading from the center of the pan. The low temperature was measured at 256.6° C. The low was based on a temperature reading from the outer edge of the pan. The third set of data also includes a graphical representation of the pan with the temperature reading of the different areas around the pan.

The fourth set of data has temperature measurements after heating the vessel for 10 minutes with the microwave oven. The average temperature was measured at 277.3° C. The high temperature was measured at 294.8° C. The high was based on a temperature reading from the center of the pan. The low temperature was measured at 267.1° C. The low was based on a temperature reading from the outer edge of the pan. The fourth set of data also includes a graphical representation of the pan with the temperature reading of the different areas around the pan.

FIG. 16shows the results of a second exothermic test performed on a second microwave vessel with a piece of ferrite rubber. Specifically, this figure shows an exothermic test for a pan (e.g., a pizza pan) that has a diameter of 260 mm. The ferrite rubber is the primary heating element for this second text test. The test was performed with a 1000 Watt (W) microwave oven. The results show the temperature in degrees Celsius (C).

As shown inFIG. 16, the results include four sets of data. The first set of data has temperature measurements after heating the vessel for just 1 minute with the microwave oven. The average temperature was measured at 155.0° C. The high temperature was measured at 187.5° C. The high was based on a temperature reading from the center of the pan. The low temperature was measured at 137.0° C. The low was based on a temperature reading from the outer edge of the pan. The first set of data also includes a graphical representation of the pan with the temperature reading of the different areas around the pan.

The second set of data has temperature measurements after heating the vessel for 3 minutes with the microwave oven. The average temperature was measured at 236.7° C. The high temperature was measured at 256.6° C. The high was based on a temperature reading from the center of the pan. The low temperature was measured at 223.1° C. The low was based on a temperature reading from the outer edge of the pan. The second set of data also includes a graphical representation of the pan with the temperature reading of the different areas around the pan.

The third set of data has temperature measurements after heating the vessel for 5 minutes with the microwave oven. The average temperature was measured at 254.6° C. The high temperature was measured at 271.0° C. The high was based on a temperature reading from the center of the pan. The low temperature was measured at 245.0° C. The low was based on a temperature reading from the outer edge of the pan. The third set of data also includes a graphical representation of the pan with the temperature reading of the different areas around the pan.

The fourth set of data has temperature measurements after heating the vessel for 10 minutes with the microwave oven. The average temperature was measured at 271.4° C. The high temperature was measured at 284.6° C. The high was based on a temperature reading from the center of the pan. The low temperature was measured at 260.3° C. The low was based on a temperature reading from the outer edge of the pan. The fourth set of data also includes a graphical representation of the pan with the temperature reading of the different areas around the pan.

Embodiments described herein also provide a multi-layered exothermic microwave cooking apparatus.FIG. 17illustrates a perspective view of a multi-layered exothermic microwave cooking apparatus1700according to some embodiments of the invention. The cooking apparatus has an exothermic vessel1705. In some embolisms, the vessel has an exothermic lid1710that is at least partially made with the same material as that of the outer shell body1730of the vessel1705.

In some embodiments, the vessel1705and/or the lid1710are/is made with exothermic plastic. Exothermic plastic is high-heat resisting plastic mixed in with exothermic particles. For instance, the exothermic plastic may be a piece of polyphenylene sulfide (PPS) plastic mixed with exothermic particles. Also, for instance, the exothermic plastic may be a piece of syndiotactic polystyrene (SPS) plastic mixed with exothermic particles. The exothermic particles generate thermal emery (i.e., heat) by reacting to microwaves. In some embodiments, the exothermic particles include ferric oxide (Fe2O3) powder mixed with Manganese (Mn) and Zinc (Zn) powder, or copper-nickel-zinc (Cu—Ni—Zn) powder.

In some embodiments, the vessel1705and/or the lid1710are/is made with exothermic rubber. Exothermic rubber is high-heat resisting rubber mixed with exothermic particles. For instance, the vessel1705ofFIG. 17can be made with silicone rubber that is infused with exothermic particles.

The vessel ofFIG. 17has multiple shells, including the outer body shell and an inner shell or plate, that when coupled creates an inner chamber as will be described below. To release excess pressure within the inner chamber (not shown), the vessel1705has a safety pressure release valve1715installed on the side wall of the vessel. The pressure relief valve1715releases heated vapor from the inner chamber when the vessel is microwaved and pressure builds up in the inner chamber. The valve1715prevents the vessel's body or outer shell1730from being bent out of shape or cracked when pressure in the inner space reaches a certain threshold limit.

The vessel1705has an inner surface plate shell or cooking plate. In the example ofFIG. 17, the inner plate is coated with a ceramic coat1735. The ceramic coating is exothermic in that in can generate thermal energy when it is bombarded with microwaves.

As shown inFIG. 17, the multi-layered exothermic microwave cooking apparatus1700of some embodiments has a lid1710. Different from the lid shown inFIG. 1, the lid1710ofFIG. 17does not have a silicone ring that is placed between the lid and vessel. InFIG. 1, the silicone ring prevents sparks from forming between the metallic lid and metallic vessel when that apparatus is in use. However, in the example ofFIG. 17, the lid1710and body1730are made of exothermic plastic, and there are no two metal pieces that are in close proximity to one another to create such sparks.

In the example ofFIG. 17, the lid1710is dome shaped or high-dome shaped. The dome shape promotes convection cooking or, in other words, allows hot air to circulate within the cooking area in order to cook food from all sides. So that the lid does not disengage from the vessel, the lid1710may include one or more vent holes1725as illustrated inFIG. 17. Different embodiments can have different-shaped lids or even no lid at all. In some embodiments, the lid1710includes a tempered glass disc such as the one illustrated inFIG. 3.

In some embodiments, the lid1705has a handle1720. In the example ofFIG. 17, a hole is pierced on about the center of the convexed plastic plate body1740of the lid1710. A screw or coupling member (not shown) is inserted into that hold in order to couple the handle1720to the lid1710. The handle1720can be formed on the lid with the exothermic plastic or exothermic silicone rubber. However, in such embodiments, the handle may be too hot to handle when the exothermic lid is heated with a microwave oven.

In some embodiments, the apparatus's vessel1705has multiple layers or a stack of items to generate and retain heat.FIG. 18shows a cross-sectional view of the different layers of the exothermic vessel ofFIG. 17.

As shown inFIG. 18, the vessel1705includes an exothermic plastic body shell1730that is shaped as a container. The vessel also has a cooking plate shell1805having top and bottom faces. The cooking plate1805is coated with a ceramic coat1735. The ceramic coat1735can generate heat from microwave radiation.

The container body1730has a bottom surface1820and at least one side wall1825. The cooking plate1805closes the exothermic container1730to create a cooking surface, and to form an inner space1800or chamber between the bottom surface1820and the plate1805. In some embodiments, the plate and container is securely couple to one another via different methods known to those skilled in the arts. In the example ofFIG. 18, the plate1805is shaped like a container and sits firmly on the rim1830of the exothermic container1730. The two containers1730and1805may be glued or fastened to one another as well.

In some embodiments, the vessel1705includes an exothermic heating plate1810that is in contact with the outer bottom face of the inner cooking plate shell1805. The heating plate1810may be glued or fastened in some manner to the bottom face of the cooking plate1805. The exothermic heating plate1810further generates heat from microwave radiation. In some embodiments, the exothermic heating plate1810is made by blending Fe2O3, Mn, Zn, and silica powder with alumina (Al2O3) ceramic. The exothermic heating plate1810of some embodiments contains fibrous material or is wrapped with fiber, such as glass wool fiber.

In some embodiments, the exothermic vessel1705has an insulating material1815in the inner space1800of the vessel. Different embodiments can use different insulating material. For instance, the insulating material may be an insulation mat1815as illustrated inFIG. 18. Also, for instance, the insulating material may be quilted or shaped material (e.g., such as a heat-retaining microporous thermal quilted panel).

In some embodiments, the inner space1800has a reactive material to further insulate the vessel1705. In some embodiments, the reactive material is getter that can absorb heated air and retain it for several hours. In some embodiments, a deposit of getter material is placed in the inner space1800of the multi-layered container1705. In some embodiments, the getter comprises zirconium (Zr). In some embodiments, the getter is primarily zirconium-based in amount or volume but can include one or more other elements, e.g., aluminum (Al), cobalt (Co), iron (Fe), etc.

FIG. 19shows a top view of the exothermic vessel1705shown inFIG. 17. As shown, the cooking plate1805is covered with the ceramic coat1735. The plate1805has several grill marks in order to allow grilling with the vessel1705. In some embodiments, the apparatus's plate is made with metal (e.g., copper, aluminum, stainless steel, or some other steel). In some embodiments, the plate is made with metal alloy such as carbon steel. In some embodiments, the plate is made of ceramic.

FIG. 20shows a bottom view of the exothermic vessel shown inFIG. 17. Specifically, the figure shows the outer bottom surface of the exothermic plastic container1730. Several legs or support structure2005a-dare formed directly on the outer bottom surface1820of the container1730.

FIG. 21shows a perspective view of the exothermic heating plate1810of the apparatus ofFIG. 17. As mentioned above, in some embodiments, the exothermic heating plate1810is made by blending Fe2O3, Mn, Zn, and silica powder with alumina (Al203) ceramic. As shown, the exothermic heating plate1810of some embodiments contains fibrous material or is wrapped or lined with fiber. The fiber gives the heating plate structural integrity to the alumina ceramic. That is, the lined-fiber assists in preventing the piece from falling apart (e.g., bending and cracking) when it rapidly changes temperature during use.

FIG. 22illustrates a perspective view of an insulation mat1815of the apparatus ofFIG. 17. The insulation mat1815is placed in inner space to trap heat. In some embodiments, the thickness or width of the mat closely matches the height of the inner space. In some embodiments, the inner space contains glass cloth for insulation. In some embodiments, the inner space includes a quilted panel. The panel may be made using glass cloth. The panel may be sewn into a pillow-like shape and filled with silica powder mixture. The panel may be sewn first closed and then compressed. The sewing technique allows the panel to be flexible. For instance, the quilted panel can be wrapped around the outer side wall of the inner shell of the double-walled vessel. The panel can also withstand abuse that the cookware is subject. That is, the panel is resistant to various vibration and motion of the vessel. Depending on the size of the inner chamber, the thicknesses of the panel may change.

In some embodiments, inner space contains a thin sheet of micro-porous insulation material. The thin sheet may be made with a micro-porous board material. As the board can be delicate, it might be coated in some manner to reinforce the board material. The thin sheet may be made primarily with pyrogenic silica. The thin sheet may be reinforced in some manner (e.g., with e-glass filament, oxide opacifier, etc.).

In some embodiments, the inner space includes a piece of foam to keep food items hot for several hours. In some embodiments, the foam is made of polyurethane. In some embodiments, the inner space is at least partially filled with a chemical gel. In some embodiments, the chemical gel includes ammonium nitrate, calcium chloride, sodium chloride, sodium acetate, and ammonium chloride. One of the benefits of using such a gel is for its endothermic performance or its ability to absorb heat. That is, the gel can be used to keep food cold for an extended period of time.

In some embodiments, the inner space may be at least partially filled with the thermal conductive medium. As a first example, the inner space may be filled with the above-mentioned fibrous medium. As another example, the inner space may be filled with the thin sheet of microporous material. In some embodiments, the inner space is at least partially filled with a set of one or more thermal conductive pads. The inner space can be filled at least partially with a thermal conductive gel. For faster heat absorption and transfer, the inner space may include a silicone-based material that is mixed with an aluminum oxide compound. In some embodiments, the inner space is at least partially filled with a silicone rubber having ferrite particles (e.g., manganese zinc (MnZn) ferrite particles). As mentioned above, in some embodiments, the inner space has a reactive medium (e.g., getter).

In some embodiment, the apparatus1700has safety valve1715.FIG. 23shows a safety pressure release valve that is installed on the side wall1825of the apparatus ofFIG. 17. The valve1715prevents the exothermic plastic or rubber container from being bent out of shape and cracked when vapor pressure in the inner space reaches its threshold limit.

FIG. 24shows an exploded view of the valve ofFIG. 23. The valve of some embodiments has the following parts: a cap2405, a head2410, a spring2415, a washer2420, and a housing2450.

In some embodiments, the cap2405is made of metal or metal alloy. The cap2405also has one or more discharge ports or holes to let out excess pressure. The head2410of the valve fits into the cap2405. The metal spring2415pushes the head2410against the cap2405to substantially close the holes2425and2430. The housing2450, which may be metal, is coupled with the cap2405to house the head2410and metal spring2415. The housing2450has at least one matching discharge port2435or2440as the head2405.

The safety valve may also include the washer (e.g., a silicone rubber cap2420). The washer is placed around the hole2445formed on the inner side wall1825of the vessel. The washer's inner circle on one side may fit into the hole2445, while the other side's inner circle may fit into the cap2405.

In some embodiments, the apparatus uses a spring-less valve.FIG. 25shows a pressure control valve2500according to some embodiments of the invention. The silicone rubber valve can replace the head2410and spring2415of the valve1715ofFIGS. 23 and 24. As shown, the valve2500, in some embodiments, is made of an elastic or compressible material. The valve2500includes a head2505having a conical figure so as to open/close an opening formed on the outer shell of the vessel. The valve also includes a support frame2515that extends from the head2505. The shape of the head2505may be of a spherical shape and the like. The diameter of the head2505is large enough to effectively seal the opening formed on the outer shell of the cooking vessel.

In some embodiments, a recess2520is formed on the head2505(e.g., on the side nearest to the opening formed on the outer shell) so as to receive a large force (pressure) generated from concentrating the pressure within the inner chamber of the vessel (e.g., on to the smaller square area of the recess instead of the whole side of the head2505nearest to the opening).

In some embodiments, the head2505extends from a support frame2515, which has a hollow cylindrical figure, by a neck2510, which is securely attached or formed next to the head and the support frame. In the example ofFIG. 25, the diameter of the neck2510is smaller than the diameter of the support frame2515, thus facilitating the compressibility of the valve2500. Also, this difference in diameter facilitates further discharge of excess pressure through the support frame2515as well. At low temperatures or when there is insufficient pressure (e.g., steam pressure) generated within the inner chamber, the head2505effectively seals the opening formed on the outer shell to prevent unnecessary heat loss.

In some embodiments, the valve2500is made with silicone rubber because of its elasticity as well as its resistance to high temperature.

FIG. 26shows the results of a first exothermic test performed on the multi-layered vessel ofFIG. 17. The test was performed with a multi-layered vessel having a 260 millimeter (mm) diameter. The test was performed with a 1000 Watt (W) microwave oven. The results show the temperature in degrees Celsius (C).

As shown inFIG. 26, the results include four sets of data. The first set of data has temperature measurements after heating the vessel for just 1 minute with the microwave oven. The average temperature was measured at 129.9° C. The high temperature was measured at 151.9° C. The low temperature was measured at 114.8° C. The first set of data also includes a graphical representation of the pan with the temperature reading of the different areas around the pan.

The second set of data has temperature measurements after heating the vessel for 3 minutes with the microwave oven. The average temperature was measured at 273.9° C. The high temperature was measured at 305.3° C. The low temperature was measured at 242.4° C. The second set of data also includes a graphical representation of the pan with the temperature reading of the different areas around the pan.

The third set of data has temperature measurements after heating the vessel for 5 minutes with the microwave oven. The average temperature was measured at 336.8° C. The high temperature was measured at 363.5° C. The low temperature was measured at 320.5° C. The third set of data also includes a graphical representation of the pan with the temperature reading of the different areas around the pan.

The fourth set of data has temperature measurements after heating the vessel for 10 minutes with the microwave oven. The average temperature was measured at 388.3° C. The high temperature was measured at 426.4° C. The low temperature was measured at 348.2° C. The fourth set of data also includes a graphical representation of the pan with the temperature reading of the different areas around the pan.

FIG. 27shows the results of a second exothermic test performed on the multi-layered vessel ofFIG. 17. For this test, the multi-layered vessel was a pizza pan with a diameter of about 260 mm. The test was performed with a 1000 Watt (W) microwave oven. The results show the temperature in degrees Celsius (C).

As shown inFIG. 27, the results include four sets of data. The first set of data has temperature measurements after heating the vessel for just 1 minute with the microwave oven. The average temperature was measured at 115.1° C. The high temperature was measured at 128.7° C. The low temperature was measured at 103.8° C. The first set of data also includes a graphical representation of the pan with the temperature reading of the different areas around the pan.

The second set of data has temperature measurements after heating the vessel for 3 minutes with the microwave oven. The average temperature was measured at 250.0° C. The high temperature was measured at 273.9° C. The low temperature was measured at 237.4° C. The second set of data also includes a graphical representation of the pan with the temperature reading of the different areas around the pan.

The third set of data has temperature measurements after heating the vessel for 5 minutes with the microwave oven. The average temperature was measured at 317.0° C. The high temperature was measured at 348.3° C. The low temperature was measured at 292.4° C. The third set of data also includes a graphical representation of the pan with the temperature reading of the different areas around the pan.

The fourth set of data has temperature measurements after heating the vessel for 10 minutes with the microwave oven. The average temperature was measured at 353.5° C. The high temperature was measured at 422.0° C. The low temperature was measured at 320.5° C. The fourth set of data also includes a graphical representation of the pan with the temperature reading of the different areas around the pan.

As indicated above, the apparatus of some embodiments has an exothermic heating plate having a top face that is in contact with outer bottom surface of the inner shell. This is to transfer the generated heat to the cooking surface. Several different versions of multi-layered vessels with such an exothermic heating plate will now be described by reference toFIGS. 28-31. These figures are similar toFIGS. 8-11, but include the heating plate1810shown inFIGS. 18 and 21.

FIG. 28illustrates a double walled vessel2800of the microwave cooking apparatus according to some embodiments. This figure is similar toFIG. 8, but it shows the plate1810.

FIG. 29illustrates a double walled vessel2900of the microwave cooking apparatus according to some embodiments. This figure is similar toFIG. 9, but it shows the plate1810. Also, in this figure the outer shell2905is made with exothermic PPS plastic.

FIG. 30illustrates a double walled vessel3000of the microwave cooking apparatus according to some embodiments. This figure is similar toFIG. 10, but it shows the plate1810. Also, in this example, the inner shell is wrapped with ferrite silicone rubber3005(e.g., having Fe2O3, Mn, Zn, and silica). Also, the bottom inner space between two shells is insulated with ceramic wool fiber3010.

FIG. 31illustrates a double walled vessel3100of the microwave cooking apparatus according to some embodiments. This figure is similar toFIG. 11, but it shows the plate1810. Also, in this example, the inner shell is wrapped with ferrite silicone rubber3105(e.g., having Fe2O3, Mn, Zn, and silica).

While the invention has been described with reference to numerous specific details, it is to be understood that the invention can be embodied in other specific forms without departing from the spirit of the invention. For instance, any one of the vessels described above without the coat of exothermic enamel glaze can be coated with that glaze. Thus, one of ordinary skill in the art would understand that the invention is not to be limited by the foregoing illustrative details, but rather is to be defined by the appended claims.