Abstract: An apparatus and method for heating a sample, such as chemical reaction mixtures are disclosed. The apparatus may include at least a microwave generator, a waveguide for guiding the generated microwaves to an applicator, and a deflector formed by a closed loop defining a plane. The deflector may have an inherent resonance frequency and a thickness in a direction normal to the plane. The deflector may be rotatable around an axis being at least substantially parallel to the plane, and 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 may be easily adjustable by rotating the deflector. The resonance conditions and the coupling factor may be adjusted in response to the dielectric properties of the sample in order to optimize the amount of absorbed power and thereby obtain control of the sample heating process.

Abstract: A microwave applicator for heating loads being a waveguide transition between the rectangular TE10 and TE20 modes comprising a TE10 mode section and a TE20 mode section. The location of the load being inside said TE20 mode section and with its major axis perpendicularly to the major propagation direction of the TE20 mode, close to a shorting wall of said TE20 mode section and also close to the centreline of said propagation direction.

Abstract: Microwave heating apparatus comprising an elongated dielectric microwave applicator with an axial TM type mode, said dielectric applicator is provided with a load chamber for a load to be heated, said load chamber is located in a centered axial position inside the applicator. Two microwave feeding points are arranged at a lower end of the applicator for feeding microwave energy in the axial direction of the applicator so that significant cross-talk between the applied microwaves is avoided.

Abstract: A Microwave heating system includes an elongated cylindrical metal cavity intended for heating a voluminous elongated load. The system includes microwave feeding means arranged to generate a single mode of the circular type TEm;n;p (a so-called whispering gallery mode) inside the cavity in order to heat the elongated load, wherein the circumferential index m is at least 4, the radial index n=1 and the axial index p being >0. The heating system is preferably adapted for wood processing.

Abstract: 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.

Abstract: Microwave heating apparatus comprising a dielectric microwave applicator provided with a microwave coupling means adapted to feed microwave energy to the applicator. The applicator is provided with a load chamber 8 extending coaxially with regard to the centre axis of the applicator from an upper end to a predetermined distance from a lower end of the applicator, said load chamber is adapted to receive a load to be heated. The dielectric applicator comprises two sections, an upper section 4 provided with the load chamber and a lower section 6 for impedance matching between the coupling means and upper section. In a preferred embodiment the lower section has an increasing cross-sectional area from the coupling means to the intersection to the upper section.

Abstract: Microwave heating system comprising an elongated cylindrical metal cavity intended for heating a voluminous elongated load.

Abstract: Microwave heating apparatus comprising a dielectric microwave applicator provided with a microwave coupling device adapted to feed microwave energy to the applicator. The applicator is provided with a load chamber 8 extending coaxially with regard to the centre axis of the applicator from an upper end to a predetermined distance from a lower end of the applicator, the load chamber is adapted to receive a load to be heated. The dielectric applicator comprises two sections, an upper section 4 provided with the load chamber and a lower section 6 for impedance matching between the coupling device and upper section. In a preferred embodiment the lower section has an increasing cross-sectional area from the coupling device to the intersection to the upper section.

Abstract: 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.

Abstract: Microwave heating apparatus comprising a dielectric microwave applicator provided with a microwave coupling means adapted to feed microwave energy to the applicator. The applicator is provided with a load chamber 8 extending coaxially with regard to the center axis of the applicator from an upper end to a predetermined distance from a lower end of the applicator, said load chamber is adapted to receive a load to be heated. The dielectric applicator comprises two sections, an upper section 4 provided with the load chamber and a lower section 6 for impedance matching between the coupling means and upper section. In a preferred embodiment the lower section has an increasing cross-sectional area from the coupling means to the intersection to the upper section.

Abstract: The present invention relates to a microwave applicator for heating loads being a waveguide transition between the rectangular TE10 and TE20 modes comprising a TE10 mode section and a TE20 mode section. The location of the load (4) being inside said TE20 mode section and with its major axis perpendicularly to the major propagation direction of the TE20 mode, close to a shorting wall (3) of said TE20 mode section and also close to the centreline of said propagation direction.

Abstract: Microwave heating apparatus comprising an elongated dielectric microwave applicator with an axial TM type mode, said dielectric applicator is provided with a load chamber for a load to be heated, said load chamber is located in a centered axial position inside the applicator. Two microwave feeding points are arranged at a lower end of the applicator for feeding microwave energy in the axial direction of the applicator so that significant cross-talk between the applied microwaves is avoided.

Abstract: 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.

Abstract: A method of drying wooden objects according to the invention shall be carried out in a closed treatment room (10) with a supply of microwave effect which heats the objects stacked in a unit so that the moisture is pressed out and removed. Each unit is positioned in a cover of heat insulation stuff which prevents cooling of the wooden objects by the air circulation in the room.

Abstract: A microwave radiator assembly comprising an oven cavity, an antenna chamber communicating with the oven cavity by radiation openings and an antenna structure energized by a microwave generator. The introduction of radiation into the oven cavity is effected by an arrangement comprising a metallic plate in which said radiation openings are carried out and a coupling pin mounted in a microwave-transparent plate projecting through each opening forming coaxial paths into the oven chamber.

Abstract: An electric supply circuit for a microwave oven provided with a magnetron tube in which an anode circuit is supplied with high tension, the circuit comprising a mains supply, a leak field transformer having a primary winding and a secondary winding, the secondary winding supplying the anode circuit, two parallel branches connecting the primary winding of the transformer to the mains supply, a first one of the two branches including a switch and a protective resistor serially connected, a second one of the two branches including a relay contact, and a relay coil being connected in series to the protective resistor and forming an additional branch which is connected in parallel to the primary winding of the transformer, the relay coil controlling the relay contact, the first one of the branches being closed upon actuation of the switch supplying the relay coil and the primary winding via the protective resistor, the second one of the branches being closed upon exitation of the relay coil to close the relay cont