Abstract: An assembly for applying microwave irradiation to a load having a generally circular cross-section. The applicator supports a dominant TM.sub.120 mode and the load is aligned with a central axis in the applicator, with each aperture of a pair of feed apertures diametrically opposed (for the circular cross sectional case) or located on parallel opposed walls (for the polygonal cross sectional case) with one of the pair of feed apertures positioned at 90 degrees with respect to the other pair about the axis. The applicator may be formed as a cylinder or as a polygonal prism of the type having parallel opposed sides, such as those having a square, hexagonal or octagonal cross-section. Means such as a microwave transparent tube or conveyor provide for positioning of the load in the applicator. In an alternative embodiment, two cavities are used, with one cavity associated with each of the two feed systems, and a means for conveying the load from the first cavity to the second cavity is provided.

Abstract: A connection device for two successive segments (1A, 1B) of a tunnel oven for cooking food, comprises a first sleeve (16A) fixed to the frame (18) of the tunnel and second sleeve (17) secured to the tunnel segments (1A, 1B). The second sleeve (17) is mounted axially slidable relative to the first sleeve (16A). Seals (25) are disposed between the first and second sleeves, within the thickness of these latter, so as to permit sliding without loss of sealing. The device also comprises, in series, a quarter wave trap (26) and a body (31) that absorbs microwaves, also disposed within the thickness of the device.

Abstract: An apparatus, system, and method, for using circular mode magnetic microwave energy to heat the interior regions of a work piece of wood fiber and glue. The microwaves are generated and transmitted as rectangular waveguide mode microwave energy, and are converted by mode converter to circular magnetic mode microwave energy. As circular magnetic mode microwave energy, the microwave energy passes through a work piece or billet of material is reflected on the other side, and travels through the billet a second time. Reflected microwave energy from the main reflected wave as well as reflections from other structures, surfaces and layers in the system travel back toward the microwave source. They are sensed, and a computer tuning system causes capacitive probes to generate offsetting microwave reflections, which are opposite in phase and equal in magnitude to the sum of all of the reflected waves.

Abstract: A plant for pasteurizing or sterilising solid or liquid food products subjects the previously packaged products to heat treatment using microwaves in a pressurized chamber, in order to guarantee its conservation for long periods of time. At least three phases of operation include a rapid heating phase of the products, up to a temperature which is slightly lower than the pasteurizing or sterilising temperature; and a temperature equalising phase, and a cooling phase. The pressure inside the pressurised chamber, during the phases varies as a function of the temperature reached by the products. The plant includes a number of tubular elements (2, 3, 4; 11, 12, 13, 14), each of which consists of a number of sections (2a, 3a, 4a; 11a, 12a, 13a, 14a) cylindrical in shape and of a small diameter, each tubular element having devices for inserting and removing from it the products to be treated and for varying the ambient pressure inside it, as function of the temperature reached by the products.

Abstract: A system and method for pasteurizing citrus juice with the use of microwave energy provide a plurality of microwave chambers through which juice is continuously flowed, the sequential flowing permitting a gradual increase in juice temperature that is sufficient to pasteurize the juice but insufficient to cause a detectable loss of flavor.

Abstract: A microwave refining and melting furnace for the treatment of dissolved or solid products includes a first waveguide traversed by a microwave beam generated by a generator coupled to a first end of the first waveguide. The first waveguide is provided with a material supply orifice located at an upper part thereof close to a first end of the first waveguide. The first waveguide has at a lower part thereof, close to a second end, an overflow lock of variable height making it possible to define a retention volume for the materials, which have been progressively melted by a continuous flow along the lower wall of the first waveguide, from the reception point thereof in the first guide. A second waveguide is connected to the first waveguide for refining the materials.

Abstract: A continuous denitration apparatus capable of ensuring mass processing of a nitrate solution of a nuclear fuel and a continuous stable operation. By a rotation of screws, uranium nitrate solution supplied from a liquid feed inlet is continuously conveyed. A trough is divided into a concentration zone, a denitration zone and a drying zone. Microwaves emitted from a microwave incident inlet pass through a microwave permeable part provided in a critical shield plate for covering the upper part of the trough and are applied to the uranium nitrate solution of high concentration and high viscosity, conveyed by the screws. The uranium nitrate solution is denitrated to prepare a denitrated product (uranium trioxide). This denitrated product is dried in the drying zone to obtain powder to be discharged from an outlet.

Abstract: The tunnel oven comprises an elongated enclosure connected to an inlet closure and an outlet closure and traversed by a conveyor transporting the food to be cooked. The enclosure is delimited by a wall forming a floor, a wall forming a ceiling, and two side walls of which one is provided with a door giving access to the interior of the enclosure. The enclosure is divided into several successive cooking chambers separated from each other in the upper portion of the latter, each chamber being associated with several different heaters, including microwave heaters. The microwave heaters of each chamber comprise several sources provided with microwave emission members disposed in the wall forming the ceiling of the chamber such that one microwave emission member will be offset relative to a neighboring microwave emission member, in the direction of advance of the food.

Abstract: A two-zone lime mud calciner is provided for processing lime mud from kraft pulp recovery operations. A conveyer is employed for conveying lime mud horizontally through the calciner. The first zone and second zone of the calciner each contains a dielectric hysteresis heating device for first drying the lime mud in the first zone and then decomposing the dried lime mud to lime and carbon dioxide. A co-current flow of purge air removes steam generated in the first zone and a counter-current flow of purge air removes carbon dioxide generated in the second zone with a vent being provided adjacent the upstream and of the second zone.

Abstract: A system and method for pasteurizing citrus juice with the use of microwave energy provide a plurality of microwave chambers through which juice is continuously flowed, the sequential flowing permitting a gradual increase in juice temperature that is sufficient to pasteurize the juice but insufficient to cause a detectable loss of flavor.

Abstract: An apparatus assembly for heating a product has a tunnel and microwave generators positoned for generating a microwave field zone within the tunnel. A conveyor belt extends within the tunnel for passing a product through the tunnel. A plate formed of a material impermeable to microwaves is positioned in the tunnel so that an entire width of the belt passes over the plate in the microwave field zone so that microwave energy is reflected away from the belt. In addition, heating elements for generating an infrared energy zone and a further conveyor belt may be positioned so that a product passed through the tunnel then is passed by the further conveyor belt through the infrared energy zone.

Abstract: An apparatus for drying a fried food has a dry chamber being provided with separated chambers in which the food is transported in order, a microwave oscillator for supplying a microwave energy to the respective separated chambers, and hot blast generator for supplying heated air to the respective separated chambers. The length in the food forward direction of each of the separated chamber is equal to or longer than that of just before chamber. The microwave energy supplied to each of the separated chamber corresponds to the water content of the fried food passing through the chamber.

Abstract: A new microwave autoclave apparatus, and a method for pasteurizing, sterilizing or retorting food product in a continuous mode, and in commercial quantities, using microwave radiant energy. In this new microwave autoclave apparatus, containers of food-stuff are held tightly within individual moving bottom vessel, and a corresponding moving top cover. The moulds therefrom, made of a material which is permeable to microwave radiation, are linked together to form a chain such that a continuous flow of container enters and leaves a microwave chamber. The synchronization of the moving top covers with the moving bottom vessels, and the opposing forces applied thereupon provide tightly fitted cavities capable of supporting substantial pressure, and thus providing a retort effect. The moulds prevent undesired expansion of containers during heating periods, without applying adverse pressure beyond its original shape during the cooling phase.

Abstract: The invention relates to an arrangement for microwave radiation of materials, in particular of the starting materials for ceramic materials, alloys etc., having a conveying path that is defined at least in part by a trough or pipe arrangement, the wall of which has a specific microwave-absorption capacity, a resonator surrounding at least a length of the wall, and at least one generator for generating the microwave radiation. In order to enable adjustment of the heating and the radiation dosing of the microwave-treated materials independently of one another, it is proposed according to the invention that the wall of the trough or pipe arrangement (1; 9.1 to 9.3) has different microwave-absorption properties along its length.

Abstract: Lime mud from kraft pulp recovery operations is processed using dielectric hysteresis heating, in a two-stage operation, in which wet lime mud first is dried then the dried lime mud is decomposed to lime and carbon dioxide. A two-zone lime mud calciner is employed in which the lime mud is conveyed horizontally, with drying being effected in the first zone and then decomposition being effected in the second zone. A co-current flow of purge air removes steam generated in the first zone and a counter-current flow of purge air removes carbon dioxide generated in the second zone.

Abstract: Apparatus and method for regenerating saturated adsorbents using microwave energy. A saturated adsorbent, such as activated carbon, is fed onto a continuously moving conveyor belt. The conveyor belt transports the carbon to a microwave cavity where the carbon is exposed to microwave energy. The cavity is defined by a containment enclosure which is sealed to prevent radiation leakage. The carbon is heated to a sufficient temperature to cause the contaminants to desorb. The system also includes vents for removing the desorbed contaminants and a holder for receiving the treated carbon discharged from the belt. The microwave cavity may be divided into a number of heating compartments so that the carbon on the belt is heated to different temperatures in each compartment. Each compartment is separately vented, thereby allowing selective recovery of the different contaminants in the carbon.

Abstract: A system is provided for heating non-metallic material or a discrete layer of the non-metallic material. Microwave energy is introduced into an enclosure defining a first cavity and capable of substantially containing the microwave energy. A semiconductive sheet is positioned at the bottom of the first cavity. Thermal insulation overlies the semiconductive sheet. A second cavity is defined by the undersurface of the semiconductive sheet and flexible microwave shielding in the form of a skirt which is attached to, and depends from, the enclosure. The flexible shielding is composed of a material which also substantially contains the microwave energy. The semiconductive sheet is effective to convert some of the microwave energy into thermal energy and to transmit the thermal energy into the second cavity while transmitting the remainder of the microwave energy directly to the discrete layer, thereby rapidly heating the discrete layer.