A microwave heating device which comprises a heating chamber (3) to receive an article (2) being heated, a microwave generator (11) for irradiating microwaves in the heating chamber (3), and a steam generator (12) for supplying the heating chamber (3) with steam. Provided in the heating chamber (3) are heat accumulating plates (28a, 28b) adapted to be subjected to microwave irradiation for heating and heat accumulation. Accordingly, dewing resulting from steam is reduced in the heating chamber (3).

Microwave heating device

The present invention relates to an apparatus for heating a sample, such as chemical reaction mixtures, whose dielectric properties varies during the heating process In particular, the present invention relates to a microwave heating apparatus comprising a microwave generator, a waveguide for guiding the generated microwaves to an applicator, and a deflector formed by a closed loop defining a plane, said deflector having an inherent resonance frequency and a thickness in a direction normal to said plane, the deflector being rotatable around an axis being at least substantially parallel to said plane, the deflector being positioned in the waveguide so as to form a resonant cavity with the sample and the waveguide applicator The resonance conditions of the resonant cavity and the coupling factor of radiation from the waveguide to the cavity are easily adjustable by rotation of the deflector The resonance conditions and the coupling factor can be adjusted in response to the dielectric properties of the sample in order to optimise the amount of absorbed power and thereby obtain control of the sample heating process

Microwave heating apparatus

Disclosed is an improved system and method to evaluate the status of a material The system and method are operative to identify flaws and measure the erosion profile and thickness of different materials, including refractory materials, using electromagnetic waves The system is designed to reduce a plurality of reflections, associated with the propagation of electromagnetic waves launched into the material under evaluation, by a sufficient extent so as to enable detection of electromagnetic waves of interest reflected from remote discontinuities of the material Furthermore, the system and method utilize a configuration and signal processing techniques that reduce clutter and enable the isolation of electromagnetic waves of interest Moreover, the launcher is impedance matched to the material under evaluation, and the feeding mechanism is designed to mitigate multiple reflection effects to further suppress clutter

Material erosion monitoring system and method

A variable frequency microwave heating apparatus (10') designed to allow modulation of the frequency of the microwaves introduced into a multi-mode microwave cavity (32') for testing or other selected applications. The variable frequency microwave heating apparatus (10') includes a traveling wave tube (TWT) (20). A power and temperature display/controller (60) receives input from a power monitor (62) and a temperature sensor (64). The power monitor (62) receives input from the directional coupler (24') which detects the direction and amplitude of signals incident upon and reflected from the microwave cavity (32'). The power and temperature display/controller (60) further serves to control the microwave oscillator (14'), the pre-amplifier power control (18') and the TWT power supply (22'). A cooling system (66) is provided for cooling the TWT (20). A tapered waveguide coupler (68) acts as an impedance transformer.

Variable frequency microwave heating apparatus

The present invention provides methods for decomposing and extracting compositions for the recovery of petroleum-based materials from composites comprising those petroleum-based materials, comprising subjecting the compositions and/or composites to microwave radiation, wherein the microwave radiation is in the range of from about 4 GHz to about 18 GHz. The present invention also provides for products produced by the methods of the present invention and for apparatuses used to perform the methods of the present invention.

Microwave-based recovery of hydrocarbons and fossil fuels

A variable frequency microwave heating apparatus (10) designed to allow modulation of the frequency of the microwaves introduced into a furnace cavity (34) for testing or other selected applications. The variable frequency heating apparatus (10) is used in the method of the present invention to monitor the resonant processing frequency within the furnace cavity (34) depending upon the material, including the state thereof, from which the workpiece (36) is fabricated. The variable frequency microwave heating apparatus (10) includes a microwave signal generator (12) and a high-power microwave amplifier (20) or a microwave voltage-controlled oscillator (14). A power supply (22) is provided for operation of the high-power microwave oscillator (14) or microwave amplifier (20). A directional coupler (24) is provided for detecting the direction and amplitude of signals incident upon and reflected from the microwave cavity (34). A first power meter (30) is provided for measuring the power delivered to the microwave furnace (32). A second power meter (26) detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load (28).

Apparatus and method for microwave processing of materials

A variable frequency microwave furnace system (10) designed to allow modulation of the frequency of the microwaves introduced into a furnace cavity (34) for testing or other selected applications. The variable frequency microwave furnace system (10) includes a microwave signal generator (12) or microwave voltage-controlled oscillator (14) for generating a low-power microwave signal for input to the microwave furnace. A first amplifier (18) may be provided to amplify the magnitude of the signal output from the microwave signal generator (12) or the microwave voltage-controlled oscillator (14). A second amplifier (20) is provided for processing the signal output by the first amplifier (18). The second amplifier (20) outputs the microwave signal input to the furnace cavity (34). In the preferred embodiment, the second amplifier (20) is a traveling-wave tube (TWT). A power supply (22) is provided for operation of the second amplifier (20). A directional coupler (24) is provided for detecting the direction of a signal and further directing the signal depending on the detected direction. A first power meter (30) is provided for measuring the power delivered to the microwave furnace (32). A second power meter (26) detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load (28).

Variable frequency microwave furnace system

A portable microwave instrument for evaluating characteristics of a structural member includes a source of microwave energy, a transmitter coupled to the source of microwave energy for transmitting a microwave signal at the structural member, and a receiver positioned on the same side of the structural member as the transmitter and being disposed to receive a microwave signal reflected by the structural member. A phase angle difference is determined between the transmitted microwave signal and the received microwave signal using a signal splitter and a balanced mixer. The difference in phase angle varies in accordance with differences in size, shape and locations of constituent materials within the structural member.

Portable microwave instrument for non-destructive evaluation of structural characteristics

A variable frequency microwave heating apparatus (10) designed to allow modulation of the frequency of the microwaves introduced into a furnace cavity (34) for testing or other selected applications The variable frequency heating apparatus (10) is used in the method of the present invention to monitor the resonant processing frequency within the furnace cavity (34) depending upon the material, including the state thereof, from which the workpiece (36) is fabricated The variable frequency microwave heating apparatus (10) includes a microwave signal generator (12) and a high-power microwave amplifier (20) or a microwave voltage-controlled oscillator (14) A power supply (22) is provided for operation of the high-power microwave oscillator (14) or microwave amplifier (20) A directional coupler (24) is provided for detecting the direction and amplitude of signals incident upon and reflected from the microwave cavity (34) A first power meter (30) is provided for measuring the power delivered to the microwave furnace (32) A second power meter (26) detects the magnitude of reflected power Reflected power is dissipated in the reflected power load (28)

Don W. Bible

Papers

Apparatus and method for microwave processing of materials

Variable frequency microwave furnace system

Portable microwave instrument for non-destructive evaluation of structural characteristics

Microwave heating appts. and method for material

Vorrichtung und verfahren zur mikrowellenbearbeitung von materialien