JPS63299084A - Microwave heating device - Google Patents

Abstract

PURPOSE:To efficiently heat grains by connecting a rectangular wave guide and a circular wave guide, fitting a magnetron device on the rectangular wave guide side, and arranging a container containing the grains to be heated. CONSTITUTION:A rectangular wave guide 1 fitted with a magnetron device 2 on one end side, a circular wave guide 3 connected with one end opening section to the other end side of the rectangular wave guide 1, a microwave permeating receiver plate 4 arranged at the connection portion between the rectangular wave guide 1 and the circular wave guide 3, and a dome-shaped envelope 8 covering at least the other end opening section of the circular wave guide 3 are provided, and a container 6 containing grains to be heated is mounted on the receiver plate 4. Microwaves generated in the rectangular wave guide 1 are transmitted into the circular wave guide 3, and the wavelength range at the maximum microwave energy is expanded. The heating process of grains or the like can be thereby performed efficiently in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a microwave heating device for cooking food.

BACKGROUND OF THE INVENTION Popcorn has traditionally been produced by heating corn, ie, grains of corn, using a microwave oven or the like to explode the corn. In this case, since the corn is efficiently heated from the inside, by using a 600W microwave oven, popcorn without burning can be prepared in about 3 minutes of heating treatment.

Problems to be Solved by the Invention However, this device has the following problems. In other words, a microwave oven is generally a hexahedral microwave cavity, and when heating an object such as food, multiple microwave energies are generated due to variations in load conditions such as the shape and volume of the object. It is necessary to prevent uneven heating caused by dispersing and concentrating heat in certain areas.

For this purpose, a method is used in which microwave energy is diffused using a turntable, a stark, etc., and the object to be heated is uniformly irradiated with the microwave energy.

It takes a long time to heat-process grains such as corn, and it is difficult to heat them efficiently because the corn explodes during cooking and scatters, including surrounding corn.

An object of the present invention is to provide a microwave heating device that solves the above problems.

Means for Solving the Problems To achieve this objective, the microwave heating device of the present invention connects a rectangular waveguide and a circular waveguide, and
In addition to installing a magnetron device on the rectangular waveguide side,
A container containing an object to be heated is placed inside a circular waveguide.

Effect: With this configuration, microwave energy is concentrated near the object to be heated stored in the container, and the object is efficiently cooked.

EXAMPLE An example of the apparatus of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a main part of this embodiment. In the figure, 1 is a rectangular waveguide generally called a standard waveguide.
It has a rectangular cross section, and a magnetron 2 is attached to one end. 3 is a circular waveguide whose one end opening is connected to the other end opening of the waveguide 1 . Reference numeral 4 denotes a receiving plate made of a low dielectric constant material through which microwaves are transmitted, and is placed at the junction between the rectangular waveguide 1 and the circular waveguide 3.
Together, they constitute a microwave heating chamber 5. 6 is a pot-shaped container containing grains 7 such as corn, which is put into the microwave heating chamber 5 from the open end of the three circular waveguides, and placed in the pedestal 4.
placed on top. A dome-shaped envelope 8 is arranged to cover the container 6 and the microwave heating chamber 5. If the container 6 is housed within the waveguide 3 and the openings of both have substantially the same dimensions, it is sufficient for the envelope 8 to cover the opening of the waveguide 3. This envelope 8 allows the inside to be seen through from the outside and has a microwave shielding effect.

For example, it is made of a metal net or a thin metal plate with many small holes (so-called punched metal). Reference numeral 9 denotes a cylindrical body, which is provided integrally within the envelope 8 so as to surround the opening of the container 7, and prevents the grains from scattering due to explosion. Reference numeral 10 denotes a semi-fixed stub, which is attached to the rectangular waveguide 1 so as to adjust the distribution of microwave standing waves. 11 is a magnetron 26 microwave radiation antenna.

The operation of this embodiment configured as above will be explained.

FIG. 2 shows the state of the respective inner wavelengths λ1°λ and 2 in the rectangular waveguide 1 and the circular waveguide 3 having the optimum size. Note that these wavelengths are expressed by the following equation.

Rectangular waveguide Circular waveguide Where: λ: Inner wavelength a: Long side dimension of the waveguide λ. : Cutoff wavelength 3.412 r (TE mode) In the diagram, the inner wavelength λ1 of rectangular waveguide 1 (inner dimensions 109.2MX54.6m) is 147.7m, and the inner diameter size 90 that fits this waveguide 1 is Since the internal wavelength λ12 in the circular waveguide 3 formed at +a is 202.6 m, the wavelength λ
Of course, the relationship between the wavelength range L1 of No. 11 when the microwave energy is maximum and the wavelength range L2 of the wavelength λ12 is L2>L+.

Once the microwaves generated in the rectangular waveguide 1 are transmitted into the circular waveguide 3, the wavelength range when the microwave energy is at its maximum is expanded.
This can be done efficiently and in a short time. Furthermore, the circular waveguide 5 has a smaller capacity than the rectangular waveguide 1. The S7 is easy to store and microwave energy can also be evenly supplied.

Effects of the Invention In the present invention, by connecting a circular waveguide to a rectangular waveguide, microwave energy can be concentrated on the object to be heated such as grains, and the range of concentration can be expanded. Therefore, heat treatment can be easily performed in a short time.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a main part of a microwave heating device according to an embodiment of the present invention, and FIG. 2 is a state diagram of the wavelength inside the tube in a microwave heating chamber. 1... Rectangular waveguide, 2... Magnetron, 3... Circular waveguide, 4... Receiving plate,
5... Microwave heating chamber, 6... Container, 7... Grain, 8... Dome-shaped envelope, 9... - Cylindrical body, 10...,... stub. Name of agent: Patent attorney Toshio Nakatashi Baka 1 Figure 2 1θ-Sukuf 1

Claims (2)

[Claims] (1) A rectangular waveguide with a magnetron device attached to one end, a circular waveguide with an opening at one end connected to the other end of the rectangular waveguide, and the rectangular waveguide. It has a microwave-transparent receiving plate disposed at a connecting portion with the circular waveguide, and a dome-shaped envelope that covers at least the other end opening of the circular waveguide, The microwave heating device is configured such that a container containing the container is placed on the receiving plate and positioned within the circular waveguide. (2) The microwave heating device according to claim (1), wherein the dome-shaped envelope is configured such that the inside thereof can be seen through.