Abstract: A path for a material passes through an opening and along a segment through an off-peak region of an electric field. An E-plane bend delivers an electromagnetic wave to the segment. A standing wave is used to heat the material. The peaks or valleys are pushed or pulled by a movable surface or by changing the frequency of the electromagnetic wave. A rectangular choke flange is used at the opening to the segment. A curved segment connects the segment to another segment for heating the material. According to another aspect of the invention, a segment is used to heat just the edge of a planar material.

Abstract: An electromagnetic exposure chamber has an exterior conducting surface that forms an interior cavity. The exterior conducting surface has a first substantially planar surface, a second substantially planar surface, a first end, and a second end. The first end has an opening for an electromagnetic wave. The electromagnetic wave forms an electric field. The second end has an elliptical shape that directs the electromagnetic wave to a focal region that extends from the first substantially planar surface to the second substantially planar surface. A second opening through the top surface is aligned with the electromagnetic field. It is possible to pass a material through the second opening. If the opening is aligned with the focal region, the heating is increased. If the opening is aligned with a peak of the electromagnetic wave, the heating is increased and the need for dielectric slabs is decreased. A choke prevents the escape of electromagnetic energy.

Abstract: A source provides an electromagnetic wave that has a range of frequencies. The source sweeps the frequency of the electromagnetic wave between a cutoff frequency and double the cutoff frequency. The location, angle, or effective angle of an opening is adjusted by an opening adjuster. A path for an electromagnetic wave has a short for creating a standing wave. The path has a movable surface that can push and pull the peaks and valleys of the standing wave so as to achieve more uniform heating of the material. A dielectric wheel pushes and pulls the peaks and valleys of a standing wave so as to achieve more uniform heating of a material. A dielectric structure has a surface that has a short side and a long side. A motor rotates the dielectric structure to push and pull the peaks and valleys of a standing wave so as to achieve more uniform heating of a material. A path has a first choke flange that has a width w1, and a second choke flange that has a width w2.

Abstract: A path for a material passes through an opening and along a segment through an off-peak region of an electric field. An E-plane bend delivers an electromagnetic wave to the segment. A standing wave is used to heat the material. The peaks or valleys are pushed or pulled by a movable surface or by changing the frequency of the electromagnetic wave. A rectangular choke flange is used at the opening to the segment. A curved segment connects the segment to another segment for heating the material. According to another aspect of the invention, a segment is used to heat just the edge of a planar material.

Abstract: With a device for heating parts 8 made of a microwave absorbing plastic and having a microwave generator 1 that generates microwaves of a certain wavelength, an antenna 4 to which the microwaves are conducted, having at least one free end 5 and a device 6 which surrounds the antenna 4, it is proposed that the device for shielding 6 be designed with a tubular shape, so that the device 6 has an inside diameter smaller than half the wavelength, projects beyond the free end 5 of the antenna and has an opening 7 in its end face. With this device it is possible to achieve a spatially limited and nevertheless homogeneous heating of parts 8. Furthermore a method of heating or welding, shaping or crosslinking parts made of a microwave absorbing plastic using this device is also proposed.

Abstract: A microwave applicator that provides a substantially uniform microwave field distribution over a large area, includes an elongated chamber, preferably operating in the length independent mode. A microwave source generates a microwave field at an output frequency. A waveguide or coaxial cable directs the microwave field from the microwave source into the elongated chamber, either through a side launch, end launch or multi launch. A frequency of the microwave field in the elongated chamber and the output frequency of the microwave source are matched through the use of controlled feedback of critical material and process parameters.

Abstract: The present invention utilizes dielectric slabs to provide a relatively uniform electromagnetic field to a cavity between two or more dielectric slabs. Each dielectric slab is a thickness equal to or nearly equal to a quarter of a wavelength of the electromagnetic field in the dielectric slab. In a particular embodiment, sample material is introduced into the cavity between the two dielectric slabs. This sample material may be introduced through one or more openings in the dielectric slabs. In further embodiments, specialized choke flanges prevent the leakage of energy from this cavity. In a preferred embodiment, an elliptical conducting surface directs the electromagnetic field to a focal region between the two dielectric slabs. Openings to this focal region allow sample material to be passed through this region of focused heating.

Abstract: The present invention overcomes many of the problems associated with electromagnetic exposure of planar materials. A diagonal slot compensates for the effects of signal attenuation along the propagation path. Adjustably variable path lengths allow peaks and valleys of the electromagnetic field in one exposure segment to compensate for peaks and valleys in another exposure segment. Dielectric slabs may be used to extend the peak field region between top and bottom conducting surfaces to allow for more uniform exposure of planar materials that have a significant thickness. Specialized choke flanges prevent the escape of electromagnetic energy. One or more rollers between exposure segments may be enclosed by an outer surface to prevent the escape of electromagnetic energy.

Abstract: A microwave applicator including a cylindrical elongated chamber used to process materials therein; a microwave power source capable of producing microwave power having an electric field; a waveguide connected to the chamber couples microwave power into the microwave chamber. The applicator provides microwave energy having a substantially uniform field distribution over a large area for processing materials such as a web or sheet-like product. The uniformity of the applicator is enhanced by the use of matching devices within the applicator to match the regions of the applicator with no load to regions where the load is present in a continuous manner.

Abstract: The present invention utilizes dielectric slabs to provide a relatively uniform electromagnetic field to a cavity between two or more dielectric slabs. Each dielectric slab is a thickness equal to or nearly equal to a quarter of a wavelength of the electromagnetic field in the dielectric slab. In a particular embodiment, sample material is introduced into the cavity between the two dielectric slabs. This sample material may be introduced through one or more openings in the dielectric slabs. In further embodiments, specialized choke flanges prevent the leakage of energy from this cavity. In a preferred embodiment, an elliptical conducting surface directs the electromagnetic field to a focal region between the two dielectric slabs. Openings to this focal region allow sample material to be passed through this region of focused heating.

Abstract: A rectangular microwave applicator for processing waste material. The rectangular microwave applicator generally includes an upper cavity and a waste container. The upper cavity defines side walls and a ceiling, the bottom of the upper cavity is open. A screwfeeder tube is positioned on and extends through one of the side walls, and a vent is positioned on and extends through another of the side walls. The waste container is rectangular in configuration and is receivable in the bottom of the upper cavity. The waste container holds waste material which is introduced therein via the screwfeeder tube. A microwave choke is carried across the bottom of the upper cavity and is configured to permit the entrance of the waste container in the bottom of the upper cavity. A microwave energy input is at each corner on top of the ceiling of upper cavity and extends therethrough.

Abstract: The present invention overcomes many of the problems associated with electromagnetic exposure of planar materials. A diagonal slot compensates for the effects of signal attenuation along the propagation path. Adjustably variable path lengths allow peaks and valleys of the electromagnetic field in one exposure segment to compensate for peaks and valleys in another exposure segment. Dielectric slabs may be used to extend the peak field region between top and bottom conducting surfaces to allow for more uniform exposure of planar materials that have a significant thickness. Specialized choke flanges prevent the escape of electromagnetic energy. One or more rollers between exposure segments may be enclosed by an outer surface to prevent the escape of electromagnetic energy.

Abstract: A method of dispensing the material that is heated by microwave energy immediately before the material is dispensed. The method comprises a series of steps including conveying the material through a pressurized passage through a dispensing tube that has radial boundaries transparent to microwave energy. The dispensing tube is located within a microwave resonant chamber. The microwave energy is channeled from a microwave generating source along a waveguide to the microwave resonant chamber. Material within the passage is heated by the microwave energy and produces a TM.sub.020 heating profile with negligible heating at the radial boundaries of the dispensing tube. The material is dispensed onto a component along a path. The dispensing step requires a measure of time to define a dispensing cycle. The output of the microwave generating source is varied. The amount of microwave heating that occurs within the material is dependent upon the output of the microwave generating source.

Abstract: An apparatus and method for the continuous processing of a granular material in a wet or dry state. The apparatus comprises first and second heating chambers, and the heating energy is provided by microwave energy. The first chamber preheats the granular material to lower the moisture content. The second chamber heats the granular material to the desired high temperature, for example, 800.degree. C. for the reactivation of carbon. The first and second chambers are arranged in a vertical orientation to allow gravity to assist in the flow of material through the chambers. The flow of material is controlled by a valve positioned at the outlet of the second chamber. The apparatus is suitable for the reactivation of metallurgical carbon and the heating of other granular materials such as ceramics and glass powders.

Abstract: The present invention provides a new and useful method for bringing about a metallurgical effect in a metal-containing ore or concentrate comprising treating said ore in a resonant microwave cavity while maximizing electric field strength in the area of said ore in said cavity.

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: An apparatus for heating a flowing fluid with microwave energy comprising a conduit having an inlet portion, an outlet portion, and a retention portion wherein at least the retention portion of the conduit is fabricated from a material which is substantially microwave transparent. A temperature probe is provided for measuring the temperature of the flowing fluid in the outlet portion. The cross-sectional area of the retention portion is substantially greater than the cross-sectional area of the outlet portion such that the flow rate through the retention portion is slower than the flow rate through the outlet portion from the retention portion to the temperature probe. Microwave energy is used to heat the flowing fluid in the retention portion, the microwave energy being generated by a source which is controlled in response to a signal from the temperature probe. The retention portion of the conduit resides within a wave guide and passes transversely therethrough.

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 microwave applicator device for continuous heat treatment of elongate products comprises an applicator housing that defines a generally rectangular waveguide cavity and at least one excitation system for exciting the cavity with microwaves propagating in TE.sub.01 transverse electric mode, the system including at least one microwave generator associated with a feed waveguide connected to the cavity via a window formed through a wall of the cavity. The front and rear walls of the feed waveguide are respectively connected to the front and rear edges of the window, and the feed waveguide is associated with a guide flap extending in the cavity in the vicinity of the rear edge of the window, and with a guide member provided substantially facing the window.

Abstract: Apparatus for heating a fiber using microwave energy. The apparatus has a source of microwave energy feeding and applicator. The applicator is configured to concentrate the microwave energy on a chamber holding a fiber. Fibers made or coated using chemical vapor deposition in the apparatus are also disclosed.

Abstract: A microwave processing system is provided wherein the material to be processed is in the form of a web type quantity configuration with a thickness that is small in relation to the wavelength of a particular microwave frequency. The material is passed through the field associated with a plurality of microwave standing waves of the particular frequency, each adjacent standing wave being offset 1/4 wavelength along the direction of movement of the web. A carrier gas removes volatile solvents from the material surfaces. Control is provided for the interrelationship of temperature, rate of movement, flow of carrier gas, and microwave power.

Abstract: Process and apparatus, in which a stream of liquid reactants is heated in a resonant microwave cavity operating in a TM.sub.0n0 mode and then provided with sufficient time in an annular plug flow reactor to complete the reaction results in improved time-temperature uniformity for all volume elements of the stream and are particularly suited for production of polyurethane prepolymer. A special cleaning method is provided for removing polymeric residues from the equipment with a solution of a monofunctional secondary amine in an organic solvent.

Abstract: A sample is heated by microwaves, and the temperature of the sample is measured by a radiation pyrometer arranged to receive radiation directly from the sample. The sample is disposed in a chamber having an orifice dimensioned to block the passage of microwaves, and admit the passage of radiation. The chamber has an upper wall in which one or more openings are formed for receiving a sample-containing receptacle.

Abstract: Apparatus for heating a fiber using microwave energy. The apparatus has a source of microwave energy feeding and applicator. The applicator is configured to concentrate the microwave energy on a chamber holding a fiber. Fibers made or coated using chemical vapor deposition in the apparatus are also disclosed.

Abstract: A process and apparatus for controlled continuous microwave digestion of samples of materials to prepare them for subsequent analyses or other chemical operations. The material to be analyzed, in finely divided form and mixed with digesting liquid, such as a strong acid, is charged as a slug into a flowing liquid carrier stream, usually water, which stream, containing the slug, is passed in a tube through a zone in which the tube and contents are subjected to microwave radiation, to heat the digesting liquid and the material to be digested to promote the digestion. The process and apparatus are modified by inclusion of detecting and controlling steps and corresponding apparatus components to detect a condition of the flowing liquid without physically contacting it, as by determining the dielectric constant of contents of the tube, or a related property of such contents at one or more locations of the tube, usually outside the microwave zone, and controlling operations of the process and apparatus accordingly.

Abstract: A microwave apparatus (10) with conductive fingers (104, 105) on extensions (101, 102) contacting the material (200) to be processed and knife edges (100) adjacent the material on opposed sides of the cavity (12). The fingers and knife edges prevent leakage of the microwaves from the cavity (12) through extensions (101 and 102) and can be replaced or modified for various material 200 and die cross-sections. The apparatus is particularly useful for curing electrically conductive resin impregnated fibers.

Abstract: In an electromagnetic-wave-operated heating apparatus in which, with a body to be heated such as a living body inserted into the cavity resonator incorporating at least one reentrant, an electromagnetic wave produced by high frequency energy supplied into the cavity resonator is used to heat the body; an electric field concentrating member is provided between the reentrant and the body in such a manner that the electric field concentrating member is provided to be electrically disconnected to the reentrant, whereby, under an ordinary condition that the body held in the apparatus is not in parallel with the end face of the reentrant, a deep portion of the body can be heated with high efficiency.

Abstract: In the heat treatment of food particularly pre-packed food it is important to control the temperature and to provide uniform heat distribution within the article, By using a number of microwave emission slots in a waveguide which are brought to resonance in the presence of pre-packed articles carried over the slots by a conveyor the rate of rise of temperature within the article is controlled without unnecessary energy loss between articles carried seriatim on the conveyor The slots may be set obliquely to the direction of passage of the article Alternatively the slots may be formed by a series of smaller slots staggered obliquely across the waveguide so that the presence of the article tunes each of the slots in turn as it passes over the waveguide. The slots may be covered with low-loss dielectric material to prevent extraneous matter falling into the slots and to space the article from the slots so as to control power dissipated.

Abstract: A microwave device for treating process liquids, preferably precursors to radiopharmaceuticals, with microwave radiation, with the intention of reducing reaction time and increasing reaction yield. The method and the device are characterized in that the geometry of the microwave cavity is varied proportionally to the geometry of the sample container in order to concentrate the microwave field within the container. The reaction time can also be shortened and the reaction yield also increased by varying the microwave field energy or microwave field frequency. The reaction time can also be decreased by adding salts to the process liquid or by adapting the frequency of the microwave field to the resonance frequency of the process liquid in the microwave spectrum.

Abstract: A method and apparatus for preparing essentially fat free chips such as potato chips and the like having an appearance and taste similar to conventional chips without the use of deep fat frying processes. The method of the present invention includes the steps of exposing sliced raw potatoes and the like to a high intensity microwave field that rapidly converts moisture within the slice into steam. These exposed slices are then dried by longer exposure to a lower energy microwave field. The apparatus of the present invention includes a meander waveguide with a microwave absorptive terminator at an end of the waveguide. Apertures are provided along portions of the waveguide for transporting the potato slices and the like through the waveguide. A belt link type conveyor belt having an open lattice structure is employed to convey raw product slices through the meander waveguide.

Abstract: A microwave applicator device for the treatment of sheet or lap products comprising a housing defining a parallelepipedal waveguide cavity with dimensions a.times.b.times.L in an orthogonal coordinate system Ox, Oy, Oz, the housing being aligned along Oz and provided with slots for passing the product to be treated into the cavity along a plane parallel to the Ox, Oz plane, and means a microwave generator for exciting the cavity in Transverse Electric Mode, in order to create an electric field (E) internal to the cavity along a direction substantially parallel to Ox. The housing is such that the dimension a of the cavity is greater than a value substantially equal to the dimension b of the cavity.

Abstract: A sample is heated by microwaves, and the temperature of the sample is measured by a radiation pyrometer arranged to receive radiation directly from the sample. The sample is disposed in a chamber having an orifice dimensioned to block the passage of microwaves, and admit the passage of radiation. The chamber has an upper wall in which one or more openings are formed for receiving a sample-containing receptacle.