SU1764190A1 - S h f furnace - Google Patents

Abstract

Usage: heating and drying of dielectric materials, such as food. Summary of the Invention; A microwave oven contains a microwave generator connected through a section of the waveguide and a radiator to a heating chamber (KN), a dielectric support for accommodating the material being heated. The dielectric stand is mounted on a shelf, made in the form of a contour closed along the perimeter of the KN circuit made of metal strips of width I / 8. The emitter consists of a square plate and a metal plate parallel to it, mounted on the inner surface of the upper wall of the SC. The square plate is connected to the waveguide section by means of a metal pin that passes through a hole in the metal plate, and with the wall of a CN, by means of a short-circuit jumper. In the upper part of the side walls of the CL are made half-wave grooves. The distance from the bottom of the CC to the shelf I / 8 where I is the wavelength of the CC, 1 Il. cl

Description

The invention relates to a technique of ultra-high frequencies, namely, the design of a serhvA of a low-frequency furnace for heating and drying dielectric materials, for example, food products.

A microwave oven is known, comprising a radiator rotating in a heating chamber, formed by a vertical rod exiting a vertical rod with a horizontal triangular-shaped segment.

Similar to the construction of the microwave oven does not provide uniform heating of the processed material.

Known microwave oven, selected as a prototype, containing a microwave generator, a waveguide, a radiator connected to a heating chamber, inside of which on a metal shelf around the perimeter of the chamber.

near its bottom, a dielectric support is installed for the material being heated. In order to distribute an electromagnetic field in a heating chamber, this construction of a microwave oven uses liquid flows transmitted through radiotransparent tubes.

A disadvantage of the known construction is the insufficiently uniform distribution of the electromagnetic field in the heating chamber and, accordingly, uneven heating of the material being processed, in particular, due to the dependence of this distribution on the load variation and parameters of the microwave generator.

The aim of the invention is to ensure uniform heating of the processed material due to uniform distribution of the microwave field in the heating chamber.

Vi o

This goal is achieved by the fact that, in the known construction of a microwave oven comprising a microwave generator connected through a section of the waveguide and the radiator to the heating chamber, a dielectric support for accommodating the heated material that is installed inside the chamber and fixed on a shelf made in the form of a closed perimeter the bottom of the heating chamber contour of metal strips, the emitter is made in the form of a square plate and a metal plate located parallel to it, which is fixed on the inner surface of the The square of the heating chamber wall, the square plate is connected to the waveguide section by means of a metal coupling pin passing through the hole in the metal plate, and the upper wall of the heating chamber by means of a short connecting jumper, the width of the metal shelf I / 8 and the distance from the shelf To the bottom of the heating chamber is H / 8, and in the upper part of the side walls of the heating chamber there are grooves of depth H / 2, where is the wavelength in the heating chamber.

Comparison of the claimed technical solution with the prototype made it possible to establish compliance with the novelty criterion. In the study of other known technical solutions in this field of technology, it was established that the proposed technical solution meets the criterion of significant differences.

The drawing shows a General view of the microwave oven

The microwave oven contains an emitter in the heating chamber 1, connected through a segment of waveguide 2 to the microwave generator 3. The emitter is made in the form of a square plate 4 and a metal plate-screen 5 parallel to it, which is fixed on the inner surface of the upper wall 6 of the heating chamber 1. For The square plate 4 is connected to the waveguide 2 by means of a metal coupling 7, passing through the insulated hole 8 in the plate-screen 5. The square plate 4 by means of short clamps Jumper jumper 9 is connected with a metal plate-screen 5, which means with the upper wall 6 of the chamber 1.

The design of the radiator, when executed, is known the calculated ratios relative to the dimensions of the elements of the waveguide-radiator path. provides excitation in the heating chamber of the microwave field with a circular insulation, the most effective for

heating electrically anisotropic materials, such as many products in particular, as well as good matching of the transmission path with the radiating system.

To compensate for interference phenomena arising due to the reflection of electromagnetic waves from the chamber walls and resulting in non-uniformity of the Floor, throttle sections in the form of grooves 10 are made in the upper part of the side walls of the heating chamber 1, half a wavelength. For exposure to electromagnetic waves on the bottom of the material being processed

5 11 inside the heating chamber 1 on the shelf 12, made in the form of a contour of metal strips closed along the bottom of the chamber, a dielectric stand 13 is fixed. In this case, the width of the shelf 12, and

0 also the distance from the shelf 12 to the bottom of the heating chamber 1 is one eighth of the wavelength in the heating chamber 1. The selection of the dimensions of the throttle notches 10, the width of the shelf 12 and the distance from the shelf 12 to

The 5 bottoms of chamber 1 is based on the results of the experiments performed. With these ratios of sizes, the value of the standing wave coefficient over the voltage Ket. And with various volumes of load, it is minimal and amounts to the order of 1.18-1.22, while the reflection loss is about 1% of the power of the microwave generator.

Thus, the use in the microwave oven 5 of the radiator, which forms an electromagnetic field with circular polarization and ensures good coordination of the transmitting path with the radiating system, as well as design features

The heating chambers, which help to improve the matching of the radiating system with the load, ensure uniform distribution of the microwave floor in the heating chamber and, consequently, uniform heating of the material being processed. It has been experimentally confirmed that the relative change in the energy of the microwave oscillations at any point in the working volume of the microwave oven is no more than 3 dB.

Claims (1)

0 claims A microwave oven containing a microwave generator connected through a section of the waveguide and the radiator to the heating chamber, a dielectric stand for 5 accommodating the heated material, which is installed inside the heating chamber and mounted on a shelf made in the form of a contour of metal strips closed along the perimeter of the bottom of the heating chamber, in order to provide heating uniformity; the radiator is made in the form of a square plate and a metal plate parallel to it, which is fixed on the inner surface of the upper wall of the heating chamber; the square plate is connected to the waveguide section by means of a metal coupling pin passing through the hole in the metal plate and the upper wall of the heating chamber is by means of a short-circuit jumper, the width of the metal strips is equal to I / 8, and the distance from the shelf to the bottom of the heating chamber is I / 8, and in the upper part of the side walls of the heating chamber there are grooves of depth I / 2, where I - the wavelength in the heating chamber.