RU2255434C1 - Microwave installation for drying loose materials - Google Patents

Abstract

FIELD: equipment for microwave drying of loose materials in food, chemical, and other industries.

SUBSTANCE: proposed microwave installation for drying loose materials has housing, drying chamber, microwave oscillator, radiator in the form of two meander lines installed for rotation about axis, cover, matching devices, drive, cylindrical screen with holes, and air feed unit communicating with space between housing and screen. The latter is made in the form of ribbed reflector with triangular ribs arranged over screen circumference, their depth being equal to λ/8 and rib-to-rib distance, λ/4; space between housing and screen is divided into even number of alternating air inlet and outlet ducts.

EFFECT: enhanced dissipation of microwave energy throughout drying chamber, uniformity of moisture removal from products, and drying efficiency.

2 cl, 2 dwg

Description

The invention relates to equipment for microwave drying of bulk materials and can be used in food, chemical and other industries.

The closest in technical essence and the achieved effect is a dryer for bulk materials [Patent No. 1617671, IPC ⁷ Н 05 В 6/64, a microwave device for processing materials of the authors Kats LI, Ershova VV, Semenova E.M. .], comprising a housing, a drying chamber, a microwave generator, an emitter in the form of two meander lines mounted rotatably around an axis, a lid, matching devices, a drive, a screen with holes, an air supply unit connected to a cavity between the housing of the heating chamber and screen.

The disadvantage is that the use of caps in this device, representing a waveguide filter with a tube radius of 10-15 times less than the wavelength of the generator, does not allow its use at such frequencies as 2450 MHz and higher, since in this case the diameter of the tubes should be 0.8-1.2 mm or less, which greatly complicates the passage of the processed material through the lids, and in most cases, the passage of the material is simply impossible. The use of a rectangular or round metal comb as a radiator ensures the concentration and uniformity of the field distribution near the inner conductor of the line, while in areas remote from the meander (comb), the field intensity decreases sharply. The passage of air only through the channel between the housing and the screen with openings located therein does not provide uniform moisture removal in the central layers of the material.

An object of the invention is to ensure maximum dissipation of microwave energy in the volume of the drying chamber, the uniformity of moisture removal from the processed material, increasing the drying efficiency.

The technical task of the invention is achieved by the fact that in a microwave installation for drying bulk materials containing a housing, a drying chamber, a microwave generator, a radiator in the form of two meander lines, mounted for rotation around an axis, a cover, coordinators, a drive, a cylindrical screen with holes , the air supply unit connected to the cavity between the housing and the screen, new is that the screen is made in the form of a ribbed reflector with triangular ribs made around the screen circumference, having a depth of λ / 8 and a distance of dy crests λ / 4, and the cavity between the housing and the screen is divided into an even number of alternating channels for the inlet and exhaust air.

The technical result is to ensure maximum dispersion of microwave energy in the volume of the drying chamber, the uniformity of moisture removal from the processed material, increasing the drying efficiency.

Figure 1 schematically shows a microwave installation for drying bulk materials; figure 2 is a section aa.

The microwave installation for drying bulk materials contains a microwave generator 1, emitter 2, cover 3, dispensers 4, a metal cylindrical body 5, a loading hopper 6, an emitter 7 made in the form of two meander lines, mounted for rotation around an axis, the first 8 and the second 9 coordinators, drive 10, screen 11, openings 12, channels 13, nozzles for supplying 14 and air exhaust 15, air supply unit 16, drying chamber 17. The screen is made in the form of a cylinder of electrically conductive material, such as copper or brass, with holes, cat size ryh less than the minimum size of the product being processed, and it represents a ribbed reflector with triangular ribs made on the screen of a circle and having a depth λ / 8 and the distance between the crests of λ / 4.

Microwave installation for drying bulk materials is as follows.

Bulk material from the loading hopper 6 through the upper dispenser 4 enters the drying chamber 17. The microwave generator 1, the drive 10 and the air supply unit 16 are turned on. The product located in the drying chamber during the operation of the microwave generator 1 is exposed to microwave radiation. An electromagnetic wave emanating from the emitter 7, passing through the product, is reflected from the screen 11. The use of triangular ribs around the circumference of the screen provides maximum dispersion of the electromagnetic wave. The emitter 7 is rotated through the rotating first and second coordinators 8 and 9 by means of a drive 10. The first coordinator 8 can be made in the form of a coaxial reactive loop and ensures minimal loss of electromagnetic energy when it moves from the microwave generator to the drying chamber.

Simultaneously with the microwave radiation from the block 16 through the pipe 14 in the channels 13 air is supplied. The number of channels depends on the overall dimensions of the drying chamber and the properties of the processed material. From the channels 13 through the openings 12, air is supplied to the drying chamber, where, passing through a layer of material, it absorbs evaporated moisture and is removed outside through the pipe 15.

The residence time of the product in the installation is regulated by dispensers, which also serve to prevent leakage of microwave radiation. The installation can operate both in batch and continuous mode.

Thus, the microwave installation we offer for drying bulk materials has the following advantages:

- provides maximum dispersion of microwave energy in the volume of the drying chamber;

- provides high uniformity of moisture removal from the processed material;

- improves drying efficiency.

Claims (2)

1. Microwave installation for drying bulk materials, comprising a housing with a drying chamber and a lid, a microwave generator connected to the emitter in the form of two meander lines, the rotation of which around the axis is carried out through the rotating first and second coordinators by means of a drive, a cylindrical screen with holes, an air supply unit connected to the cavity between the housing and the screen, characterized in that the screen is made in the form of a ribbed reflector with triangular ribs made around the screen circumference, having a depth of λ / 8 and a distance of between the crests of λ / 4, where λ - wavelength. 2. The microwave installation according to claim 1, characterized in that the cavity between the housing and the screen is divided into an even number of alternating channels for supplying and discharging air.

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