Abstract: A system for advancing trays of foor or other material to be frozen or heated through a vertically oriented housing is provided with improved means for loading the trays at one end of the housing, causing incremental advancement of the trays and removing them from the other end of the housing. The device includes a removal drawer at the outlet end which, when closed, supports the stack of trays in the device. When the drawer is opened, the stack advances downwardly and the lowermost tray in the stack is removed from the bottom of the stack and is drawn outwardly with the drawer. During opening of the drawer, other means are employed to support the stack of trays after the stack has moved downwardly one tray increment. When the drawer is reclosed, the trays are again supported by the drawer. A cold (or hot) medium is introduced into the housing at a plurality of levels.

Abstract: A disposable microwave shielding device for use in connection with controlled microwave heating of foods is formed from a dielectric sheet which is covered, on one surface, with a conductive sheet or film. The other surface of the sheet is covered or coated with a sheet or film of high temperature, burn-resistant material. The laminate or sandwich effectively precludes combustion of the dielectric sheet which might otherwise occur during heating by isolating the dielectric material from the air.

Abstract: A differential heating container for simultaneously heat conditioning a multi-component meal in which the individual food components of the meal have different heating requirements. The device includes a tray and cover which are thermoformed from plastic which is transparent to microwave energy. The rims of the tray and cover are arranged to engage each other in a snap-fit which seals the container and means are provided to destroy the seal to facilitate removal of the cover when the meal is to be served. The tray and cover are formed with ridges and walls which, when the tray and cover are combined, engage each other and cooperate to define a plurality of isolated food compartments. When the container is closed, the ridges on the cover overlap both sides of the cooperative ridges on the tray to protect the surfaces of the tray ridges and sidewalls from becoming spattered with any of the food components such as sauces, gravy, etc.

Abstract: A multicomponent food package for heating food in electrical appliances. The package is dimensioned so that the package may be properly aligned in the appliance.

Abstract: A frozen or refrigerated precooked meal formed from a number of food components is packaged in a compartmented tray which is transparent to radiant energy such as that from microwave or infrared energy sources. Each of the tray compartments is defined by ridges and side walls formed integrally with the tray and the different component foods of the meal are disposed within selected different tray compartments. A radiation transparent film is secured over the tray and is bonded to the upper edge of the tray side wall and ridges to seal each compartment. Selected areas of the seals between the film and portions of the ridges and/or tray side walls are weakened so that they may rupture in response to excessive water vapor pressure build up to enable the water vapor to escape. The sealed food tray may be placed in a specially formed shielding box which controls the quantity of radiation to which each of the food components are exposed within a given time.

Abstract: Pre-frozen complete dinners are packaged in a compartmented tray which is formed from a material transparent to microwave radiation of a frequency which would be employed to heat or partially cook the food. The tray, with the various foods of the dinner in separate compartments, is taken directly from a freezer storage and is placed in a specially designed shielding box which in turn is placed in a microwave oven to heat the food. Means are provided on the box to control the degree to which each tray compartment, and the food contained therein, is exposed to the radiation, thus controlling the degree of heating or cooking of each of the foods independently of each other. Means are provided for isolating each of the compartments fully from each other while the food is being heated to preclude contact between the separate foods and gases generated during the heating or cooking process.

Abstract: An oven employing electromagnetic radiation as a source of heat is adapted for use in the mass preparation of complete pre-frozen or refrigerated meals such as in institutional feeding environments and the like. Each meal is prepackaged and contained in a single radiation transparent tray with the various individual foods of the meal being located in selected predetermined compartments of the tray. The oven includes a lower conveyor belt which carries the tray through the oven and an upper conveyor belt which moves through the oven at the same linear speed as the lower conveyor belt but spaced above the lower belt so that the tray may be received and disposed between the belts. Each of the upper and lower belts include means defining radiation transparent apertures arranged in a predetermined array to be alignable with the different compartments in each food tray. The apertures are arranged to control the amount of radiation to which each food in each tray is exposed.

Abstract: A complete prefrozen meal is placed in a combination heating-serving container. The meal is composed of a plurality of different food items which require different quantities of heat in order to bring each of them to their intended serving temperature. The combination heating-serving container includes self-contained means associated with each food item to be heated to apply the desired quantity of heat to the food items within the same time interval. The container also includes means for isolating each of the food items from each other during the heating process. The container is thermally insulated and also includes means operable by the user to begin the heating cycle when he so desires.

Abstract: A convenience food package includes a radiation transparent plastic envelope defining sealed compartments with different food components in the respective compartments. The package configuration enables it to be used with a specially designed electrical appliance having a carrier receptive to the package. The appliance includes radiation emitting elements on opposite sides of the carriage. The carriage includes shields opaque to the radiation, the shield being provided with selectively formed radiation transparent apertures which control the degree of exposure of the individual food components in the food package to the radiation.