Personal Chemistry I Uppsala Ab

A-cell Acetyl Cellulosics Ab

Per Olov G Risman

Magnus Fagrell

Rune Simonson

Pia Larsson Brelid

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.

Microwave heating apparatus

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

Microwave applicator system

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.

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 TE (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&equals;1 and the axial index p being >0. The heating system is preferably adapted for wood processing.

Microwave system for heating voluminous elongated loads

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 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 provided with the load chamber and a lower section 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.

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.

Growing community of inventors

Härryda, Sweden

Per Olov G Risman