JP2516977B2 - Microwave heating equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a microwave heating apparatus for heating and cooking food.

2. Description of the Related Art Conventionally, popcorn has been manufactured by using a microwave oven or the like to explode grains such as corn, that is, corn, by heat treatment with microwaves to explode the corn. In this case, since the corn is efficiently heated from the inside, depending on the use of the microwave oven of 600 W, the heat treatment for about 3 minutes can produce non-burned popcorn.

Problems to be Solved by the Invention However, this device has the following problems. That is, an oven of a microwave oven is generally a hexahedral microwave cavity, and when heating an object to be heated such as food, microwave energy is usually generated by changing the shape and volume of the object to be heated and load conditions. It is necessary to prevent uneven heating caused by dispersal and concentration at points. Therefore, a method is used in which microwave energy is diffused by using a turntable, a stirrer, or the like and the object to be heated is uniformly irradiated. It takes a long time to heat-treat grains such as corn, and the corn explodes during heating and scatters including surrounding corn, so it is difficult to heat efficiently.

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

Means for Solving the Problems In order to achieve this object, the microwave heating device of the present invention connects a rectangular waveguide and a circular waveguide, and mounts a magnetron device on the rectangular waveguide side. At the same time, a container containing the object to be heated is arranged in the circular waveguide.

Action With this configuration, microwave energy is concentrated in the vicinity of the object to be heated contained in the container, and it is efficiently cooked.

Embodiment An embodiment of the device of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of the main part of this embodiment. In the figure, reference numeral 1 denotes a rectangular waveguide generally called a standard waveguide, which has a rectangular cross section and has a magnetron 2 attached to one end side. Reference numeral 3 denotes 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 that allows microwaves to pass therethrough, which is arranged at a joint portion between the rectangular waveguide 1 and the circular waveguide 3 and constitutes a microwave heating chamber 5 together with the circular waveguide 3. To do. Reference numeral 6 denotes a cup-shaped container containing grains 7 such as a corn, which is placed in the microwave heating chamber 5 from the opening end on the circular waveguide 3 side and placed on the pedestal 4. 8 is a dome-shaped envelope, which is a container 6
And it is arrange | positioned so that the microwave heating type 5 may be covered. If the container 6 is housed in the waveguide 3 and the openings of the two have substantially the same dimensional relationship, it is sufficient for the envelope 8 to cover the opening of the waveguide 3. The envelope 8 can see through the inside from the outside and has a microwave shielding function. For example, it is made of a metal net or a thin metal plate (so-called punching metal) having a large number of small through holes. Reference numeral 9 denotes a tubular body, which is integrated with the inside of the envelope 8 so as to surround the opening of the container 7 and prevents scattering of the grain due to explosion. A semi-fixed stub 10 is attached to the rectangular waveguide 1 so that the distribution of the standing wave of the microwave can be adjusted. Reference numeral 11 is a microwave radiating antenna of the magnetron 2.

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

FIG. 2 shows the states of the in-tube wavelengths λ _g1 and λ _{g2 in} the rectangular waveguide 1 and the circular waveguide 3 having optimum dimensions. In addition, these wavelengths are represented by the following equations.

Rectangular waveguide Circular waveguide Where λ _g : Wavelength in the tube a: Long-side dimension of the waveguide λ _c : Cutoff wavelength 3.412r (TE mode) In the figure, the rectangular waveguide 1 (internal dimension 109.2 mm × 54.6 m
guide wavelength lambda _g1 in m) is 147.7Mm, the guide wavelength lambda _g2 in circular waveguide 3 formed in a compatible inner diameter 90mm in the waveguide 1, because it is 202.6Mm, wavelength lambda _g1
Wavelength range L ₁ and wavelength λ _g2 at maximum microwave energy of
Of course, there is a relation of L ₂ >> L ₁ with the wavelength range L _{2 of} .

Once the microwave generated in the rectangular waveguide 1 is transmitted into the circular waveguide 3 and the wavelength range at the time of maximum microwave energy is expanded, the heating process for grains and the like is efficient and It can be done in a short time. In the circular waveguide 5, the rectangular waveguide 1
The container 7 can be stored more easily than that, and the microwave energy can be evenly supplied.

EFFECTS OF THE INVENTION According to the present invention, by connecting a circular waveguide to a rectangular waveguide, microwave energy can be concentrated on an object to be heated such as grain, and the range of concentration can be expanded. Therefore, the heat treatment can be easily performed in a short time.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a microwave heating apparatus according to an embodiment of the present invention, and FIG. 2 is a state diagram of a wavelength in a 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 …… Cylinder, 10 …… Stub.

Claims (2)

(57) [Claims] 1. A rectangular waveguide having a magnetron device attached to one end thereof, a circular waveguide having one end opening connected to the other end of the rectangular waveguide, and the rectangular waveguide. A microwave permeable receiving plate, which is disposed at a connecting portion between the tube and the circular waveguide, and a dome-shaped envelope that covers at least the other end opening of the circular waveguide, and is heated. A microwave heating device in which a container containing an object is placed on the receiving plate and is arranged in the circular waveguide. 2. The microwave heating apparatus according to claim 1, wherein the dome-shaped envelope is configured so that the inside can be seen through.