Alcan International Limited

Other

Beckett Technologies Corp.

Richard M Keefer

Melville D Ball

Bryan C Hewitt

Cindy M Lacroix

Claude P Lorenson

Active elements are described which modify the heating of foodstuffs and other microwave-heatable loads and which are responsive to changes of load dielectric properties with temperature or as a result of changes of state, composition or density during heating, to the presence of absence of loads, and to the presence or absence of adjacent dielectric materials. The active elements, which may be looped slots or strips, are constituted so as to be or become resonant or non-resonant during microwave heating of the load in response to the presence or absence of the load or the presence or absence of adjacent dielectric material. The elements conveniently may be constructed of electroconductive metal or artificial dielectric material.

Microwave packaging structures

Smart microwave packaging structures

A method and device for enhancing the heating of a surface layer of an article being heated by microwave energy is characterized by directing the energy through the surface layer into a main portion of the article in such a manner that the modes of the energy are in cut-off in the surface layer.

Methods and devices used in the microwave heating of foods and other

A susceptor for use in the heating of a foodstuff or other material in a microwave oven is constructed to have at least two regions (12,14) which are each adapted to couple with and absorb microwave energy for the generation of heat in such regions, which heat is then radiatively and conductively transferred to the material. The invention is characterized by one such region (12) having a different lossiness from the other (14), the regions being contiguous with each other. They preferably have a stepwise discontinuity of lossiness between them, which causes higher order mode or modes of microwave energy to be generated or accentuated. The susceptor may be a separate panel or may be a wall component, e.g. the bottom, of a container or utensil, or a removable cover therfor.

Susceptors for microwave heating and systems and methods of use

A product comprises a shallow container and a load located therein for heating by microwave energy. This product is designed either to be used with, or itself to incorporate, a structure for generating or enhancing at least one mode of the microwave energy of an order higher than a fundamental mode that is determined by boundary conditions resulting from the lateral dimensions of either the container of the load or both. The invention resides in controlling the depth of the load in the container in such a manner that, upon irradiation of the product with the microwave energy, the power absorbed by the load from a higher order mode is at or near a maximum value, while preferably the power absorbed by the load from the fundamental mode is at or near a minimum value. Since uneven heating would ordinarily be associated with the predominance of a fundamental mode, the result of this invention is to increase the intensity of a higher order mode relative to the fundamental mode intensity, and thus provide improved microwave heating uniformity.

Improved uniformity of microwave heating by control of the depth of a

A container for holding a body of material such as foodstuff to be heated in a microwave oven, including a dielectric lid and/or other dielectric wall structure with at least two ontiguous dielectric wall portions of respectively different electrical thickness for cooperatively modifying the microwave electric field patterns that would obtain in the body during such heating if the lid and/or other dielectric wall structure were of uniform electrical thickness or were absent. At least one of the portions, preferably the portion of higher electrical thickness, may be so constituted as to undergo a change in dielectric constant during the microwave heating, thereby to alter the heating distribution in the body as heating proceeds.

Microwave container with dielectric structure of varying properties and

A container for holding material such as foodstuff to be heated in a microwave oven, including an open-topped tray and a lid for covering the tray to form a closed cavity, wherein at least one surface of the container has one or more electrically conductive plates and/or microwave-transparent apertures for generating a microwave field pattern having a higher order than that of the fundamental modes of the container, such that the field pattern so formed propagates into the contained material to thereby locally heat the material.

Microwave container and method of making same

A container for containing a material to be heated in a microwave oven, having at least one stepped structure protruding into or out of the container from a surface thereof, this structure including a side wall or side walls that define boundary conditions that generate a microwave field pattern within the container having a higher order than that of the fundamental mode of the container.

Package of material for microwave heating including container with

A container for holding a body of material to be heated in a microwave oven, the container having at least one surface provided with a structure for generating within the container a microwave energy mode of a higher order than that of the container fundamental modes, wherein the mode generating structure has a periphery formed with a multiplicity of protuberances distributed around its perimeter for diffusing the heating effect of the higher order mode microwave energy.

Container for microwave heating including means for modifying microwave

For determining doneness of a body of food or other material heated in a microwave oven, a device including an indicator that changes appearance at a predetermined temperature, mounted on an outwardly-facing major surface of a thin-gauge metal element which is disposed in the oven so as to receive heat from the body. The metal element may be mounted on the lid or other wall of a container holding the body in the oven; the lid may be microwave-transmissive and may hold the metal element spaced above the body. The indicator may include a substance that melts at the predetemined temperature to reveal an underlying color or pattern on the metal element surface. In use, the device is placed in a microwave oven together with the body and is observed visually, for detection of the change of appearance, which occurs when the indicator reaches a temperature corresponding to adequate doneness of the body.

Systems and methods for determining doneness of microwave-heated bodies

A novel cover arrangement is described for use with foodstuff holding pans to be heated in a microwave oven. The cover is one which in terms of microwave energy, does not transmit reflected energy. Thus, the cover acts in a manner analogous with non-reflecting coatings in optics and permits passage of the microwave radiation into the container holding the foodstuff, while substantially preventing escape of microwave radiation reflected from the foodstuff surface and container bottom. In this manner the microwave energy is retained and concentrated within the container, resulting in more efficient and uniform heating of the foodstuff. The novel cover is particularly valuable when used with aluminum foil pans, which without the cover of this invention seriously reflect microwave radiation.

Growing community of inventors

Peterborough, Canada

Richard M Keefer