FR2645391A1 - Microwave applicator fed under Brewster incidence - Google Patents

Abstract

Tubular system with rectangular, square, circular or other cross-section allowing microwaves to be applied by an auxiliary waveguide forming with the moving or stationary product an angle under Brewster incidence, the polarisation of the electric field being in the plane of incidence. The waveguide is made from sheet metal, optionally perforated, and which allows the volatile products to be evacuated without losing waves. It is of a size suitable to allow the propagation of the waves in the presence of the material. This system makes it possible optionally to have a waveguide which is very close to the cutoff in the absence of the material which will cause energy dissipation in the absence of product. Several apparatuses may be arranged in series, with different angles adapted to the variation in the Brewster angle in line with the transfer or depending on the nature of the product to be treated, for this purpose the waveguide may include an articulated link making this adjustment possible and thereby making it possible to obtain the corresponding Brewster angle. In the case of bonding wood, for example, at an angle of about 22 DEG may be involved, for dried wood. The exact values of the angles being those which lead to minimum energy return to the generators.

Description

MICROWAVE APPLICATOR
FEED BY BREWSTER INCIDENCE
Tubular system of rectangular, square, circular or other cross-section, allowing the application of microwaves by auxiliary waveguide forming with the moving product or at a stop an angle under incidence of BRE
WSTER, the polarization of the electric field being in the plane of incidence.

The exact value of the angle will be that which will lead to a return of energy to the minimum generators.

DESCRIPTION
The invention has set itself the goal of a handset comprising the principle of applying microwaves, described in a nonlimiting manner with reference to the example as shown in the sketch. The function and the animation are obtained by the installation of a tubular system of rectangular, square, or other section (3) forming treatment cavity and guide means. The material to be treated (possibly wood for our example) will scroll in the said guide (3) by all mechanical or other means that are known per se.

The scroll guide (3) is equipped with a wave guide (2) which will be fixed so as to obtain the material chosen at the angle of BREWSTER (Ex: around 220 for wood). The waveguide can be made of preferably non-magnetic perforated sheet (the diameter of the holes allowing the evacuation of harmful products without leakage of waves). The waveguide is of an appropriate size to allow propagation of the waves in the presence of the material.

This system possibly making it possible to have a waveguide very close to the cut in the absence of material which will cause energy dissipation in the absence of product. These devices can be placed one after the other and have angles whose variation will follow the change in the nature of the product to be treated and the corresponding evolution of the BREWSTER angle (see sketch). Optionally, the waveguide may include an articulated connection, impervious to wave leaks, allowing this adjustment (see sketch), intended to minimize energy returns to the generators. These can be arranged alternately so as to supply successively each side of the guide-tunnel which can also be split in the case where the products to be treated are on a carpet which would cross
The waveguide (2) is equipped with a welded flange allowing the rigid attachment of a generator (1). The frequency will be 2450 MHz or other frequency authorized for industrial, scientific or medical applications, and of restored power of 800 W, 1200 W or several kW. There may be one or more applicators corresponding to this technical characteristic.

These applicators and generators will comply with the standards in force, in particular concerning microwave leaks. The electrical part complies with the standards in force. This applicator according to the chosen material and therefore the corresponding BREWSTER angle, will deliver the microwave the material according to the example chosen previously. For example, it may be a wooden coil with an angle of about 220. The exact values being those which will lead for each of the generators to minimum energy returns.

Claims (6)

1. Microwave treatment module comprising a tubular system, of rectangular, square, circular or other section (3) forming a treatment cavity for the product, scrolling or stopped, at an angle at the incidence of BREWSTER. 2. module according to claim 1, characterized in that said product processing cavity is crossed by a variable speed device, by gear motor, by gravity or by any other means. 3. Module according to any one of the preceding claims, characterized in that the waveguide is made of non-magnetic sheets. 4. Module according to any one of the preceding claims, characterized in that the waveguide comprises an articulated connection, tight against leakage of waves and allowing this angle adjustment. (pl I / II, fig 1) 5. Module according to any one of the preceding claims, characterized in that the generator (1) whose frequency is one of the frequencies authorized for industrial, scientific or medical applications, in particular the frequency 2450 NHz with restored powers of eOOW . 1200W, or several kW. 6. Microwave treatment device characterized in that it consists of several modules, according to any one of the preceding claims, arranged one after the other with angles whose variation follows the change of nature of the product to be treated by corresponding evolution of the BREWSTER angle (pl II / II, fig 2), the exact values of which will be those which will lead to a return of energy to the minimum generators.