RU2355133C1 - Uhf oven for continuous processing of heat-insulated dielectric items - Google Patents

Abstract

FIELD: electrics.

SUBSTANCE: invention concerns devices of thermal processing of heat-insulated materials and can be applied in production of construction units. UHF oven includes chamber of heating by UHF currents, UHF generator (power supply unit), waveguide and conveyor. At one end of heating chamber a wall carrying power supply unit is mounted. Power supply unit is made in the form of rectangular waveguide and emission rod and is sealed from heating chamber case by dielectric shell of radio permeable material. Heating chamber houses part of metal tube passing through wall coaxial to waveguide. Conveyor with molds filled with dielectric material passes over the tube and carries air supply system. Length of tube section placed inside heating chamber is not less than one quarter of wavelength in heating chamber. Power supply unit is mounted between side surfaces of heating chamber and tube.

EFFECT: reduced power and labour cost of production of heat-insulated dielectric items with homoporous structure, uniformity of durability and thermal physical parametres over the whole bulk of item.

5 cl, 1 dwg

Description

The invention relates to devices for heat treatment of heat-insulating materials and can be used for the manufacture of building blocks.

Known container microwave oven (patent No. 2060600 RU, 05/20/1996), consisting of a heating chamber with microwave currents, a conveyor and locks at the inlet and outlet of the heating chamber, which, according to safety requirements, reduce the intensity of electromagnetic waves to 10 μW / cm ² . The gateways are equipped with rotating reflective curtains, with the ability to rotate 1/2 wavelength. However, this design increases labor costs and does not ensure uniformity of strength and thermophysical characteristics of the product due to the residual content of excess moisture and gases unevenly distributed over the volume of the product.

An object of the invention is to expand the technical capabilities of the device, improving the quality of thermal insulation products.

The technical result of using the invention is to reduce energy and labor costs in the manufacture of heat-insulating dielectric products having an equal pore structure, ensuring uniformity of strength and thermal characteristics of the product throughout the volume.

The specified technical result is achieved due to the fact that the microwave conveyor furnace contains a heating chamber with microwave currents, a microwave generator (energy input unit), a waveguide and a conveyor, and at one end of the heating chamber there is a wall on which the energy input unit is located, made in in the form of a rectangular waveguide and a radiating pin, and sealed from the housing of the heating chamber by a dielectric cup of radiolucent material. In the heating chamber is located part of the metal pipe passing through the wall and installed coaxially with the waveguide. The joint between the pipe and the wall is hermetically sealed with a special perforated plate. Inside the pipe there is a conveyor with molds filled with dielectric material, on which the air supply system is located. The length of the pipe portion located in the heating chamber is selected to be equal to or greater than a quarter of the wavelength in the heating chamber. An energy input unit is installed between the side surfaces of the heating chamber and the pipe. The ratio of the diameters of the heating and the pipe is selected from the condition:

Dd≈λ _cr · E ₂ ,

Where

D is the diameter of the heating chamber;

D is the pipe diameter;

λ _cr - the wavelength in the heating chamber (round waveguide);

λ _cr · E ₂ is the critical wavelength of E ₂ .

The drawing shows a microwave oven for continuous processing of insulating dielectric products.

The installation comprises an energy input unit made in the form of a rectangular waveguide 1 and a radiating pin 2 mounted on a wall 7, which is located at one end of the heating chamber 3. A conveyor 4 with molds for dielectric material 5 and an air supply system passes through a pipe 6, which, in turn, through the wall 7 partially protrudes into the heating chamber 3. The length of the pipe portion 6 located in the heating chamber 3 is selected to be equal to or greater than a quarter of the wavelength in the heating chamber 3. The energy input unit is sealed from the body of the heating chamber EVA 3 with a dielectric cup 8 of radiolucent material. The heating chamber 3 has at the end a narrowing 9.

Microwave oven for continuous processing of insulating dielectric products operates as follows. The energy supplying waveguide 1 converts the main wave E of a rectangular waveguide using a pin 2 into a wave E _{2 of a} coaxial waveguide, which propagates in the heating chamber 3 in the space between the round casing of the heating chamber 3 and the pipe section 6 in the direction from the wall 7 and interacts with the heated material of the product 5. Due to the fact that the length of the pipe section 6 located in the heating chamber 3 is selected to be equal to or greater than a quarter of the wavelength in the heating chamber 3, which plays the role of a waveguide, stable excitation is ensured. wave _E2.

Since the energy input unit is removed from the product heating zone, the wave excitation zone of E ₂ does not affect the heating process, i.e. on uniformity.

Since the existence of a wave in a coaxial waveguide is determined only by the ratio of the diameters of the heating chamber 3 and the metal pipe 6, therefore, for the furnace, the restriction on the dimensions of the heat-treated product is practically removed.

Unused energy, representing about 11% of the installation’s power, enters the outlet section 9, where it is completely absorbed by the dielectric material 5.

Air purge with t = 110 ° C removes excess moisture and gases from the surface of the product, creates a temperature gradient directed from the center of the product to its surface, due to which vapors and gases are removed from the mass of material, according to partial pressures depending on the temperature gradient.

The above conditions created by the microwave oven contribute to the uniform removal of both excess moisture and gases in the volume of the product until the pores are closed, which provides the same strength and thermophysical characteristics throughout the volume of the product with its various configurations and sizes.

Using the proposed microwave oven, building blocks of 588 × 288 × 200 mm in size were obtained, which were used in the construction of buildings, followed by their cladding.

From the existing level of technology, technical solutions have not been identified that have a similar set of essential features, which meets the condition of patentability - “novelty”.

The set of essential features of the proposed technical solution allows you to get a new technical result, which meets the condition of patentability "inventive step".

The proposed microwave oven can be used for the manufacture of building blocks of various sizes and configurations, which meets the condition of patentability "industrial applicability".

Claims (5)

1. Microwave oven for the continuous processing of heat-insulating dielectric materials, containing a heating chamber with microwave currents, a microwave generator (energy input unit), a waveguide and a conveyor, characterized in that at one end of the heating chamber there is a wall on which an energy input unit is located, made in the form of a rectangular waveguide and a radiating pin, and sealed from the housing of the heating chamber by a dielectric cup of radiolucent material, as well as in the heating chamber, there is a part of a metal pipe passing through henka, and installed coaxially with the waveguide, and in such a way that a conveyor with molds filled with dielectric material is placed inside the pipe, and an air supply system is also placed. 2. Microwave oven for continuous processing of heat-insulating dielectric materials according to claim 1, characterized in that the length of the pipe section located in the heating chamber is selected to be equal to or greater than a quarter of the wavelength in the heating chamber. 3. Microwave oven for continuous processing of insulating dielectric materials according to claim 1, characterized in that the energy input unit is installed between the side surfaces of the heating chamber and the pipe. 4. Microwave oven for continuous processing of insulating dielectric materials according to claim 1, characterized in that the ratio of the diameters of the heating chamber and the pipe is selected from the condition
Dd≈λ _cr · E ₂ ,
where D is the diameter of the heating chamber;
D is the pipe diameter;
λ _cr - the wavelength in the heating chamber (round waveguide);
λ _cr · E ₂ is the critical wavelength E2. 5. Microwave oven for continuous processing of insulating dielectric materials according to claim 1, characterized in that the heating chamber has a narrowing at the end.