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: A microwave heating apparatus includes a magnetron (6) mounted on a top surface of a wave guide (7). A bottom surface of wave guide (7) is inclined towards the bottom of the wave guide opening. A metal plate (9) is provided with a predetermined clearance above the bottom surface of wave guide (7). The microwaves are irradiated from an antenna (10) of magnetron (6) and travel along the bottom surface of wave guide (7). The microwaves are guided to an opening (8) under regulation by a metal plate (9) dispersion, and thus the microwaves reach the opening without suffering from the loss of energy. An object of heating (1) is irradiated directly by the microwaves with an improved heating efficiency.

Abstract: In a high-mode microwave resonator for high-temperature treatment of materials, the resonator comprises a housing with a polygonal cross-section formed by planar housing wall segments and planar end walls. One of the end walls includes an in-coupling window arranged so as to direct a microwave beam into the resonator at an angle with respect to the housing axis and toward an edge between adjacent wall segments such that the microwave beam is divided, upon reflection, into two symmetrical beam components which, upon further reflection, provide for an essentially homogeneous field distribution throughout the resonator interior.

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: A microwave oven including a defrosting step in which a target which must be heated is irradiated with microwaves which are irregular in terms of time at least when the phase of water in the target is shifted from a solid body to liquid. The microwave oven includes a magnetron for generating microwaves for dielectrically heating a target which must be heated; and a waveguide through which microwaves generated by the magnetron are propagated into a heating chamber, wherein a defrosting process is performed in such a manner that microwaves which are irregular in terms of time and which are in a chaos state are propagated through the waveguide at least when the phase of water in the target is shifted from a solid body to liquid.

Abstract: A microwave processing system comprising a microwave applicator and a microwave source. A microwave source generates a microwave field at an output frequency. 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: A microwave applicator includes an elongated chamber, preferably having a cylindrical shape, for processing materials therein. A waveguide, connected to the elongated chamber, couples microwave power into the elongated chamber. The cross-sectional area of the elongated chamber can be mechanically adjusted to control and maintain the microwave field uniformity and resonant mode, preferably the length independent mode TM.sub.010, during the processing of the material. The applicator can thus provide microwave energy having a substantially uniform field distribution over a large area for processing materials in a non-continuous, semi-continuous or fully continuous manner.

Abstract: A microwave applicator includes an elongated chamber, preferably having a cylindrical shape, for processing materials therein. A waveguide, connected to the elongated chamber, couples microwave power into the elongated chamber. The cross-sectional area of the elongated chamber can be mechanically adjusted to control and maintain the microwave field uniformity and resonant mode, preferably the length independent mode TM.sub.010, during the processing of the material. The applicator can thus provide microwave energy having a substantially uniform field distribution over a large area for processing materials, for example, a web or sheet like product, plywood and pre-impregnated cloth, in a continuous manner.

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: 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 microwave applicator (10) including a tunable cavity (12) having by an elongated casing formed from a transition section (14) axially secured between upstream and downstream end sections (16) and by first and second end assemblies (28) each axially movable in the elongated casing. A tube assembly (72) passes through and is rotatably supported within tubes (36) of the end assemblies (28) and passes through the elongated casing. Material in the tube assembly (72) in the elongated casing and between the end assemblies (28) are subjected to microwave power introduced into the transition section (14) by a waveguide (110) via an opening 20. The axis of the tube assembly (72) is adjustably offset from that of the elongated casing and the transition section (14) is adjustably fixed at various circumferential positions to superimpose the material bed in the tube assembly (72) with the area of highest field strength.

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: The present invention is an improved method and apparatus for supplying electromagnetic energy to a body having at least one substantially planar surface comprises moving over the planar surface a self-propelled container housing a source of electromagnetic energy and having an open side which is substantially perforate to the electromagnetic energy thereby permitting transmission of the energy from the container to the body while all other surfaces of the container substantially block transmission therethrough. Concurrently with the movement of the container responding within the container to at least one selected parameter to control the movement of the container over the planar surface.

Abstract: A microwave processing system is disclosed. The system is particularly useful for concurrently controlling a plurality of chemical reactions from a single microwave source. The system comprises a source that produces electromagnetic radiation in the microwave range; a waveguide in communication with the source and into which the source propagates microwave radiation; a resonator in communication with the waveguide; and an adjustable dynamic moderating device between the waveguide and the resonator for moderating the wave energy passing from the waveguide to the resonator without substantially changing the propagated mode in the waveguide.

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: There is provided a microwave waste sterilizer comprising an upper outer shell, a lower outer shell, an upper means for guiding microwave energy, a lower means for guiding microwave energy, an upper means for dispersing microwave energy, and a lower means for dispersing microwave energy. There is also provided a method for sterilizing waste materials with dual sources of microwave energy. Further there is provided a method for dispersing microwave energy into a chamber such that the dispersed microwave energy creates a flux field of substantially uniform flux.

Abstract: A device for molding products made of glass or a synthetic resin which device has a microwave generator, a microwave oven coupled to the generator and mold parts movable relative to each other provided in the microwave oven for forming molds for holding a parison of the glass or synthetic resin to be heated dielectrically.

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: A reaction vessel used in industrial applications is heated by a multiple mode microwave beam that is directed to an interior wall of the reaction vessel. The beam is in an inclined-angular fashion and the wall is arranged so the beam is absorbed and reflected from it many times to provide a helical-like reflection and absorption pattern within the vessel interior to uniformly heat the vessel wall and the material. A microwave isolator connected between a source of the microwave energy and the reaction vessel includes a quartz plate and a seal for compensating disparities in thermal expansion coefficients between the plate and a housing for the plate.

Abstract: Microwave energy may be used to dielectrically heat a medium, which can remediate the medium. An apparatus or a system employing this concept is well-suited for various environmental applications, such as in-situ remediation of soil, sludge or spills. The system comprises a microwave energy source having a preselected microwave frequency for emitting microwave energy. The system also comprises a wave-guide section having a cross-section dimensioned in accordance with the wavelength of the microwave frequency for transmitting microwave energy. A broadband mode converter may be disposed in alignment with the wave-guide section. An applicator element is disposed in alignment with the broadband more converter for applying microwave energy directly to the medium without confining the medium, thereby removing contaminants from the medium.

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 matched or dummy load for a microwave dryer having a microwave generator and a microwave applicator. The matched load includes a waveguide having opposed broad walls, opposed narrow walls, and an end wall defining a waveguide chamber. A power absorbing body made of sintered silicon carbide, casted silicon carbide, or other materials is disposed in the waveguide chamber. One or more of the walls includes means for transferring heat from the power absorbing body. A housing or shroud having an inlet and an outlet surrounds the waveguide. The means for removing heat is disposed between the inlet and outlet of the housing so that a cooling medium passed through the housing removes heat from the power absorbing body. A tuning stub is placed in front of the power absorbing body to reduce microwave reflections.

Abstract: A portable apparatus which produces high temperature and pressure steam derived from a microwave energy source for the rapid sterilization of medical and dental appliances. Items to be sterilized are placed in a detachable high pressure chamber which is then attached to the microwave powered steam source. Microwave energy is coupled into a guiding structure containing a shaped impedance transformation element so that essentially all of the microwave energy is transferred to a reaction fluid contained in a holder at the end of the matching element. The reaction fluid is rapidly vaporized and the resulting vapors rapidly expand into the chamber through a metal screen that also prevents transmission of microwave energy. Pressure temperature values internal to the chamber are used to control application of microwave power thereby maintaining an optimum micro-organism kill condition for a prescribed time interval.

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: Method and apparatus for in vivo or in vitro selective deposition of microwave power patterns in lossy dielectric materials, particularly biological tissue. Configured as a needle-like probe, a miniature coaxial cable (1) having a circumferential gap (12) in the shield (2) is wrapped with an electrically thin dielectric substrate (18). The cable center conductor (6) extends immediately past gap (12) and is shorted to cable shield (2). A thin conductive dipole resonator (21) is positioned on substrate (18) and over gap (12) to achieve inductive coupling between the cable center conductor (6) and the dipole resonator (21) through gap (12). The ends of the dipole resonator (21) are capacitively (22) loaded so as to make the current on resonator (37) more uniform and to greatly reduce and stabilize the resonant frequency to be essentially insensitive to the dielectric properties of the surrounding material.

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 heat treatment installation for parts made of a composite material having a ceramic matrix and including a treatment enclosure which is connected to a microwave generator by a waveguide and which includes a press for hot pressing a part to be treated in the enclosure and a gas source for introducing a protective gas into the enclosure.

Abstract: A microwave oven includes a heating chamber, a turntable provided in the oven, a magnetron, a waveguide for guiding the microwave generated by the magnetron into the heating chamber, an electric field sensor provided at the inner wall face of the waveguide or the heating chamber, a metal reflector provided rotatably inside the waveguide for adjusting the impedance of a load at the heating chamber side by its rotation angle, and a circuit responsive to an output of the electric field sensor for controlling the rotation angle of the metal reflector. The control circuit includes a first program for controlling the rotation angle of the metal reflector according to a first method within a predetermined time period from the start of operation of the microwave oven, and a second program for controlling the rotation angle of the metal reflector according to a second method different from the first method after elapse of the predetermined time period.

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 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.

Abstract: An electric discharge surface conditioning apparatus includes a discharge electrode consisting of an assembly of alternating conductive and non-conductive discs which rotate about an axis. The surface of the conductive discs includes a specific pattern of slots to effect a pumping action thereby enhancing the electric discharge efficiency by circulating the fluid away from the surface of the workpiece being machined. A control arrangement for controlling the orientation of the described electrode is provided.

Abstract: Some forms of EDM employ monitoring of sparking in the gap between an electrode and a workpiece to control the machining process but difficulties arise in providing a threshold which when applied to the monitoring signal indicates the onset of arcing. This problem has been found to be due to the change in amplitude which occurs with gap current in monitoring signals derived in some ways. The invention uses a threshold control circuit to provide a variable reference signal for a comparator which compares the monitoring and reference signals, the magnitude of the reference signal varying inversely with the gap current. The output of the comparator determines by way of a drive circuit and transistors whether or not voltage is applied between an electrode and a workpiece.