JPH1116675A - High frequency heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heat an heating object evenly, while generating rotating electric field with constant microwave energy strength in a heating compartment of a high frequency heating device. SOLUTION: This device is composed of a first wave guide 3 with a first magnetron 1 attached to its H surface wall 9, a second wave guide 4 which has a second magnetron 2 attached to its H surface wall 10 and is connected to another end of the first wave guide so that the H surfaces are crossing rectangularly each other at its end part opposite with which its first magnetron 1 is provided, a heating compartment 5 structured at the connecting part of each wave guide, an opening 7 opened in the guide wall of the connecting part of each wave guide and a heating object moving device 19 to reciprocate the heating object in a direction perpendicular to E surface of the electric field in the heating compartment. Thereby, rotating electric field with constant microwave energy is generated in the heating compartment and the heating object is evenly heated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency heating apparatus using two magnetrons for heating an object to be heated.

[0002]

2. Description of the Related Art A heating technique for satisfactorily heating an object to be heated has been advanced, and optimal heating, which has been considered difficult in the past, is being enabled.

In such a situation, there is an example of a high-frequency heating apparatus using two magnetrons to increase the intensity of a microwave electric field in a heating chamber. For example, as shown in Japanese Utility Model Laid-Open Publication No. 59-136194,
A high-frequency heating device that radiates microwaves from the upper part of the heating chamber to the object to be heated is mounted on a ceiling of the heating chamber by connecting two waveguides, each equipped with a magnetron, orthogonally to each other. Proposed.

[0004]

In the high-frequency heating apparatus using two magnetrons of the above-described example, high-power microwave energy can be supplied to the heating chamber, but the object to be heated is generally only the outer portion. Was heated rapidly and there was a problem that the inside could not be heated sufficiently. That is, since the direction of the electric field generated in the heating chamber is constant and not rotating, there is a problem that the microwave energy intensity of the electric field is not uniform in the heating chamber. Further, since each waveguide is connected in a so-called H-bend manner in which the respective E-planes are connected at right angles,
When microwaves radiated from each of these magnetrons are merged by electro-seeding in the waveguide, if the respective microwaves have a phase shift, the heating output sometimes decreases. There was a problem.

The intensity of the electric field due to the microwave propagating in the waveguide is zero at a portion of the waveguide that comes into contact with the tube wall, and becomes stronger as the distance from the portion in the direction perpendicular to the tube wall increases. Because of the following characteristics, the object to be heated placed in the heating chamber is near the inner wall of the heating chamber and near the center of the heating chamber,
There is a problem that uniform heating is difficult.

[0006]

In order to solve the above-mentioned problems, the present invention focuses on the direction of an electric field of a microwave supplied from two magnetrons into a heating chamber.

First, it is necessary to uniformly apply microwaves to the heating chamber from directions different by 90 degrees. For this purpose, the first magnetron is installed, for example, in a vertical portion of the heating chamber, and the second magnetron is installed in a horizontal portion of the heating chamber that is different from the above-described vertical direction. More specifically, a first magnetron is mounted on the H-plane wall at one end of the first waveguide,
A second magnetron is attached to the H-plane wall at one end of the second waveguide, and the other end of the second waveguide is connected to the first end.
A so-called E-bend connection is made so that the H planes are orthogonal to each other at the end of the waveguide where the first magnetron is not installed. The space formed by the waveguides at the connection portion is a heating chamber in which an object to be heated is stored.

At this time, it is necessary to rotate the electric field generated in the heating chamber not only in a fixed direction but also in a temporal manner. Therefore, the length of the first waveguide and the second
Is set to λg / 4.

Further, in order to uniformly heat the object to be heated placed in the heating chamber, the object to be heated is reciprocated back and forth in a direction perpendicular to the E plane of the electric field. The object-to-be-heated moving device is installed in the heating chamber.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A microwave is radiated from a first magnetron to generate a first electric field in a direction perpendicular to the H plane of the first waveguide from inside the first waveguide to a heating chamber.
Similarly, microwaves are radiated from the second magnetron, and from the inside of the second waveguide to the inside of the heating chamber,
Perpendicular to the H-plane of the first waveguide, ie, H
Creates an electric field in a direction parallel to the plane. Here, the microwave of the first magnetron and the microwave of the second magnetron have the same output and a phase difference of 90 degrees, and under such circumstances, the electric field vector of the first magnetron and the second magnetron The electric field vector generated by the orthogonal combination of the electric field vectors changes the direction over time, and becomes a rotating electric field.

The strength of the rotating electric field in the heating chamber is constant with respect to the H-plane of each waveguide, but the E-plane wall in the heating chamber with respect to the so-called E-plane perpendicular to the H-plane of each waveguide. The side is minimized, and becomes stronger as it goes away from the E-plane wall side in the vertical direction, and becomes maximum near the center of the heating chamber. Therefore, by providing a moving device at the bottom of the heating chamber, which can reciprocate the object to be heated installed in the heating chamber toward the E-face wall side in the heating chamber, the object to be heated is installed in an electric field having a constant strength. The same operation as in the state performed is obtained, and uniform heating is achieved.

[0012]

Embodiments of the present invention will be described below.

FIG. 1 is a conceptual configuration diagram of a high frequency generator of the present invention, and FIGS. 2 and 3 are cross-sectional views of the high frequency generator of the present invention. In these figures, reference numeral 1 denotes a first magnetron that radiates a microwave to an object to be heated, and reference numeral 2 denotes a second magnetron that radiates a microwave having the same output as the first magnetron 1. Reference numeral 3 denotes a first waveguide in which the first magnetron 1 is attached to an H-plane wall at one end in the longitudinal direction. Reference numeral 4 denotes a second magnetron attached to the H-plane wall at one end in the longitudinal direction. This is a second waveguide in which one end of the first waveguide 3 to which the first magnetron 1 is not mounted is orthogonally connected and is so-called E-bend connection. 5
Is a heating chamber provided at the E-bend connection portion between the first waveguide 3 and the second waveguide 4 for installing an object to be heated. Reference numeral 6 denotes a power supply control device, reference numeral 7 denotes an opening through which an object to be heated is taken in and out of the heating chamber, and reference numeral 8 denotes a door for closing the opening 7 so that it can be opened and closed. 9 is the first magnetron 1
Is the H-plane wall of the first waveguide 3 to be mounted, and 10 is the second wall.
Is the H-plane wall of the second waveguide 4 on which the magnetron 2 is mounted. Reference numeral 11 denotes an object to be heated set in the heating chamber 5,
Reference numeral 12 denotes a microwave generated by the first magnetron 1, and reference numeral 13 denotes a microwave generated by the second magnetron 2. 14 is the first
Is the electric field generated by the microwave 12 of the magnetron 1
Is an electric field generated by the microwave 13 of the second magnetron 2. 16 is a vector of the electric field 14 by the microwave 12 of the first magnetron 1, and 17 is a vector of the electric field 15 by the microwave 13 of the second magnetron 2. Reference numeral 18 denotes a combined electric field vector based on the electric field vectors 16 and 17.

FIG. 4 is a conceptual block diagram of the present invention.
FIG. 19 is a cross-sectional view taken along a line A-A ′, and reference numeral 19 denotes a heated object moving device for reciprocating the heated object 11 back and forth with respect to the opening 7 in the heating chamber 5.

Next, the operation of the embodiment configured as described above will be described. In FIG. 2, first, when the power supply control device 6 is operated, the magnetron 1 is energized and emits a microwave 12, and similarly, the magnetron 2 emits a microwave 13. The microwave 12 is electrosprayed toward the heating chamber 5 while creating an electric field 14 in a direction perpendicular to the H-plane wall 9.
13 is also seeded toward the heating chamber 5 while creating an electric field 15 in a direction perpendicular to the H-plane wall 10. That is, the electric field 14 and the electric field 15 are formed so that their directions are at right angles. electric field
The intensity of the microwave energy at 14 is the length of the arrow of the electric field vector 16, and this electric field vector 16
It enters in a direction perpendicular to the face wall 9. Similarly, the intensity of the microwave energy of the electric field 15 is the length of the arrow of the electric field vector 17, and the electric field vector 17 is set in the heating chamber 5 in a direction perpendicular to the H-plane wall 10, that is, in a direction parallel to the H-plane wall 9. To enter. The microwaves 12 and 13 electrosprayed in the heating chamber 5 merge with each other in the heating chamber 5, and the electric field vector 16 and the electric field vector 17 are synthesized. The intensity of the microwave energy of the synthesized electric field is represented by an electric field vector
16 is parallel to the H-plane wall 9 and the electric field vector 17
Is perpendicular to the H-plane wall 9, the sum of the respective electric field vectors 16 (vertical electric field vector) and electric field vector 17 (horizontal electric field vector) is obtained. Further, the waveguide 3 and the waveguide 4
Is set to λg / 4, the microwaves 12 and 13 in the heating chamber 5 have different phases. For this reason, as shown in FIG.
Since the directions of the (vertical electric field vector) and the electric field vector 17 (horizontal electric field vector) change with time, the electric field vector 18 to be synthesized rotates. Therefore, the combined electric field in the heating chamber 5 rotates as a rotating electric field while keeping the strength of the electric field constant. As a result, the intensity of the electric field in the entire heating chamber 5 is always uniform with respect to the H-plane wall 9 side of the waveguide 3 due to the effect of the rotating electric field.
The object 11 to be heated can be uniformly heated with respect to the H-plane wall 9 side of the waveguide 3 in the inside.

Further, due to the characteristics of the microwave, the heating chamber 5
The electric field strength of the E-plane wall 20 perpendicular to the H-plane wall 9 side of the waveguide 3 becomes stronger as the E-plane wall 20 side is minimized and becomes farther away from the E-plane wall side, and becomes maximum near the center of the heating chamber. Therefore, the heated object moving device provided at the bottom of the heating chamber reciprocates the heated object toward and away from the E surface of each waveguide, that is, toward the opening,
The object to be heated can be uniformly heated. As a result, the object to be heated 11 installed in the heating chamber 5 is uniformly heated inside and outside by the microwave having a constant energy. Further, when the door 8 is opened, the object to be heated automatically moves to the position before the door 8, that is, to the vicinity of the opening 7 regardless of the position of the object to be heated 11 in the heating chamber 5.

[0017]

As described above, according to the present invention, microwaves having the same output but different phases are electrosprayed into the heating chamber so that the electric field vectors of the two are synthesized at a right angle. A rotating electric field of constant microwave energy can be generated in the heating chamber, and the object to be heated can be reciprocated with respect to the inner wall side of the heating chamber having a small electric field strength. Uniform heating can be performed, and for example, frozen food in a block shape can be thawed evenly to the inside at a uniform temperature.

[Brief description of the drawings]

FIG. 1 is a conceptual configuration diagram of an embodiment of the present invention.

FIG. 2 is a cross-sectional view of one embodiment of the present invention.

FIG. 3 is a sectional view of one embodiment of the present invention.

FIG. 4 is a sectional view taken along line AA ′ of FIG. 1 according to one embodiment of the present invention;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 1st magnetron 2 2nd magnetron 3 1st waveguide 4 2nd waveguide 5 Heating chamber 6 Power supply control device 7 Opening 8 Door 9 H plane wall of 1st waveguide 10 2nd conduction H-plane wall of wave tube 11 Heated object 12 Microwave by first magnetron 13 Microwave by second magnetron 14 Electric field by microwave of first magnetron 15 Electric field by microwave of second magnetron 16 First magnetron Electric field vector by microwave of 17 Electric field vector by microwave of second magnetron 18 Synthetic electric field vector by microwave of first magnetron and microwave of second magnetron 19 Heated object moving device 20 First waveguide E-plane wall of pipe

Claims (1)

[Claims] 1. A first magnetron (1), a first waveguide (3) having the first magnetron attached to an H-plane wall at one longitudinal end, and a second magnetron (2).
The second magnetron is attached to the H-plane wall at one end in the longitudinal direction, and the other end is connected to the first waveguide of the first waveguide.
A second waveguide (4) connected at the end opposite to the side where the magnetrons are provided so that their H planes are orthogonal to each other; the first waveguide and the second waveguide. A heating chamber (5) formed at a connection part of the waveguide, and a pipe at a connection part between the first waveguide and the second waveguide for taking an object to be heated into and out of the heating chamber. An opening (7) opened in the wall,
A heating object moving device (1) for reciprocating the heating object in the heating chamber in a direction perpendicular to the E-plane of the electric field.
9).