CN111033127B

CN111033127B - Microwave processing apparatus

Info

Publication number: CN111033127B
Application number: CN201980003765.1A
Authority: CN
Inventors: 大森义治; 福井干男; 细川大介
Original assignee: Panasonic Intellectual Property Management Co Ltd
Current assignee: Panasonic Intellectual Property Management Co Ltd
Priority date: 2018-05-21
Filing date: 2019-05-15
Publication date: 2021-12-17
Anticipated expiration: 2039-05-15
Also published as: JP7378019B2; CN111033127A; EP3798518B1; JPWO2019225413A1; EP3798518A4; EP3798518A1; WO2019225413A1

Abstract

The microwave processing device includes a heating chamber for accommodating an object to be heated, an oscillating unit for generating microwaves, a radiating unit, and a heater. The heater is disposed in the heating chamber so as to form a plane facing a wall surface of the heating chamber and to be spaced apart from the wall surface by a predetermined distance. The radiation unit is disposed in the heating chamber, and radiates microwaves to a space between the heater and the wall surface so that the microwaves propagate through the space between the heater and the wall surface. According to this aspect, a wide installation area of the heater can be obtained using a small antenna, and the radiation area of the microwave can be enlarged. As a result, the heating performance of the heater and the heating performance of the microwave can be ensured at the same time.

Description

Microwave processing apparatus

Technical Field

The present invention relates to a microwave processing apparatus including a heater.

Background

Fig. 5 is a schematic diagram showing the structure of a conventional microwave processing apparatus 100. Fig. 6 is a plan view showing a ceiling 105a of a heating chamber 105 in the conventional microwave processing apparatus 100. As shown in fig. 5 and 6, in the microwave processing apparatus 100, an irradiation region 101 for irradiating microwaves and a region for installing a heater 102 are separately provided.

The radiation region 101 is configured to occupy a majority of the top portion 105 a. The heater 102 is disposed in a limited range in the ceiling portion 105a so as to surround the radiation region 101 separately from the radiation region 101. A radiation section 104 such as a rotary antenna is disposed in the radiation region 101. The oscillating unit 103 generates microwaves and supplies the generated microwaves to the radiating unit 104. With this configuration, the microwave is radiated to the entire heating chamber 105.

In such a microwave processing apparatus, there is a configuration in which a heating element is disposed at a position lower than a rotation antenna or an end portion having strong directivity of the rotation antenna is stopped at a position higher than the heating element (for example, see patent document 1).

The microwave processing apparatus described in patent document 1 is intended to realize a desired heating distribution by stopping the rotating antenna so as not to easily obstruct the orientation of the surrounding sheath heater and radiating microwaves.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2008-286457

Disclosure of Invention

However, in the above-described conventional configuration, it is difficult to heat the object to be heated in various shapes, types, and amounts stored in the heating chamber to a desired state.

That is, if a sufficient microwave radiation area is to be secured, the installation area of the heater is limited. In this case, sufficient heating performance of the heater cannot be obtained. On the other hand, if a sufficient installation area of the heater is secured, the radiation area of the microwave is limited. In this case, if the object to be heated is placed in a wide range, the heating efficiency is reduced or uneven heating occurs, and sufficient heating performance by microwaves cannot be obtained.

In order to ensure the heating performance of the heater, it is desirable to use a small antenna to obtain a wide installation area of the heater. In order to ensure the heating performance of the microwave, it is desirable to obtain a wide radiation area in which an antenna or the like is arranged so that the microwave can be radiated in a wide range. That is, to ensure both the heating performance of the heater and the heating performance of the microwave, it is necessary to solve the opposite problem.

An object of the present invention is to provide a microwave processing apparatus capable of heating objects of various shapes, types, and amounts as desired by simultaneously securing heating performance of a heater and heating performance of microwaves.

A microwave processing device according to one aspect of the present invention includes a heating chamber for accommodating an object to be heated, an oscillating unit for generating microwaves, a radiating unit, and a heater. The heater is disposed in the heating chamber so as to form a plane facing a wall surface of the heating chamber and to be spaced apart from the wall surface by a predetermined distance. The radiation unit is disposed in the heating chamber, and radiates microwaves to a space between the heater and the wall surface so that the microwaves propagate through the space between the heater and the wall surface.

According to this aspect, the space between the plane formed by the heater and the wall surface of the heating chamber can be used as the waveguide path. This makes it possible to obtain a wide installation area of the heater using a small antenna and to expand the radiation area of the microwave. As a result, the heating performance of the heater and the heating performance of the microwave can be ensured at the same time, and the object to be heated can be heated as desired.

Drawings

Fig. 1 is a schematic diagram showing a configuration of a microwave processing device according to embodiment 1 of the present invention.

Fig. 2 is a plan view of the top of a heating chamber in the microwave processing apparatus according to embodiment 1.

Fig. 3 is a sectional view of the microwave processing apparatus according to embodiment 1 taken along line 4-4 shown in fig. 1.

Fig. 4 is an enlarged view of a radiation section of the microwave processing apparatus according to embodiment 2 of the present invention.

Fig. 5 is a schematic diagram showing the structure of a conventional microwave processing apparatus.

Fig. 6 is a plan view of the top of a heating chamber in a conventional microwave processing apparatus.

Detailed Description

A microwave processing apparatus according to a first aspect of the present invention includes a heating chamber for accommodating an object to be heated, an oscillating unit for generating microwaves, a radiating unit, and a heater. The heater is disposed in the heating chamber so as to form a plane facing a wall surface of the heating chamber and to be spaced apart from the wall surface by a predetermined distance. The radiation unit is disposed in the heating chamber, and radiates microwaves to a space between the heater and the wall surface so that the microwaves propagate through the space between the heater and the wall surface.

In a microwave processing apparatus according to a second aspect of the present invention, in addition to the first aspect, the radiation section is a loop antenna having a loop plane perpendicular to the wall surface. The center of the annular plane is located in the space between the heater and the wall surface. The microwaves radiated by the radiation section propagate in an antenna projection space including the annular plane and extending perpendicularly to the annular plane.

In the microwave processing apparatus according to the third aspect of the present invention, in the second aspect, a distance between the wall surface and a portion of the radiation section that is farthest from the wall surface is 2 times or less a distance between the wall surface and a portion of the heater that is farthest from the wall surface.

In the microwave processing device according to the fourth aspect of the present invention, in addition to the second aspect, the heater traverses the antenna projection space at a plurality of positions.

In a microwave processing device according to a fifth aspect of the present invention, in addition to the second aspect, the antenna projection space extends from the annular plane in two directions perpendicular to the annular plane.

In a sixth aspect of the microwave processing apparatus according to the present invention, in addition to the second aspect, the heating chamber includes a holder that holds the heater. The holder is disposed outside the antenna projection space.

In a seventh aspect of the microwave processing apparatus according to the present invention, in addition to the second aspect, the heating chamber has an extraction portion for connecting the heater and an external power supply. The lead-out portion is disposed outside the antenna projection space.

In the microwave processing apparatus according to the eighth aspect of the present invention, in addition to the second aspect, the radiation section is disposed in the middle between the two opposing wall surfaces of the heating chamber.

In a microwave processing apparatus according to a ninth aspect of the present invention, in the second aspect, one end of the loop antenna is connected to the transmission unit via a connection unit provided on a wall surface of the heating chamber. The other end of the loop antenna is connected to the wall surface via a ground portion that is separated from the connection portion by a distance of within one quarter of the wavelength of the microwave.

In a tenth aspect of the microwave processing apparatus according to the present invention, in the second aspect, the radiation section has an annular side arranged in parallel with the wall surface.

In a microwave processing apparatus according to an eleventh aspect of the present invention, in addition to the second aspect, the radiation section includes a plurality of loop antennas. The antenna projection spaces of the loop antennas do not overlap in the heating chamber.

In a microwave processing apparatus according to a twelfth aspect of the present invention, in the first aspect, the wall surface is a ceiling portion of the heating chamber.

Embodiments of the present invention will be described below with reference to the drawings.

(embodiment mode 1)

Fig. 1 is a schematic diagram showing a configuration of a microwave processing device 50 according to embodiment 1 of the present invention. Fig. 2 is a plan view of the ceiling 1a of the heating chamber 1 in the microwave processing apparatus 50.

As shown in fig. 1 and 2, the microwave processing device 50 includes a heating chamber 1 for accommodating an object 2 to be heated, an oscillator 3, an antenna 4, a heater 5, and a transmission line 6.

The oscillation unit 3 includes, for example, a semiconductor amplifier and generates microwaves. The transmission line 6 transmits the microwave generated by the oscillator 3 to the antenna 4 via the connection portion 6a provided in the ceiling portion 1 a. The antenna 4 radiates the microwave transmitted through the transmission line 6 into the heating chamber 1. The heater 5 is a sheath heater. The heater 5 is held by a holder 8 provided on the ceiling portion 1a, and is disposed in the vicinity of the ceiling portion 1 a. In the present embodiment, the antenna 4 and the transmission line 6 correspond to a radiation unit and a transmission unit, respectively.

The antenna 4 is disposed on the top 1 a. The antenna 4 has a loop antenna structure in which one end is connected to a transmission line connected to the oscillator 3 and the other end is connected to the ceiling 1a and grounded. The annular plane 4a of the antenna 4 is perpendicular to the top 1 a.

The microwave generated by the oscillator 3 generates a high-frequency current flowing through the antenna 4. This produces a strong electromagnetic field excitation 9 at the annular plane 4a of the antenna 4. The electromagnetic field excitation 9 propagates in the antenna projection space 7 extending along the straight line X. The straight line X is a straight line passing through the center of the annular plane 4a and perpendicular to the annular plane 4 a.

The antenna projection space 7 includes a circular plane 4a, and a cross section of the antenna projection space 7 perpendicular to the straight line X has the same shape and size as the circular plane 4 a. The antenna projection space 7 can be said to be a locus of the annular plane 4a when the annular plane 4a of the antenna 4 is virtually moved along the straight line X.

The heater 5 is disposed in a ring shape at an appropriate distance from the ceiling portion 1a so as to form a plane facing the ceiling portion 1 a. The propagation direction of the electromagnetic field radiated from the antenna 4 can be made uniform by the space between the ceiling portion 1a and the heater 5. Therefore, in the present embodiment, the space is used as a waveguide path for microwaves. More specifically, the antenna projection space 7 becomes a waveguide path. Thus, even if the antenna 4 is small, the microwave can be propagated to the end of the antenna projection space 7 shown in fig. 2, that is, the end of the heating chamber 1.

The holder 8 is disposed outside the antenna projection space 7. Thus, in the antenna projection space 7 as a waveguide path, the holder 8 does not reflect and divide the microwave propagating through the waveguide path. As a result, the microwave can be reliably and efficiently propagated over the entire waveguide path even with the small-sized antenna 4.

Fig. 3 is a cross-sectional view of the microwave treatment device 50 taken along line 4-4 shown in fig. 1. As shown in fig. 3, the heater 5 is disposed at an appropriate distance from the wall surface (top portion 1a in the present embodiment) of the heating chamber 1 as described above. Thereby, as described above, the antenna projection space 7 becomes a waveguide path.

The heater 5 is disposed widely below the antenna projection space 7. The heater 5 traverses the antenna projection space 7 at a plurality of heater traversing portions 15. With this configuration, as shown by an arrow 10 in fig. 3, a part of the microwave propagating through the waveguide is branched off to the object 2 to be heated by the heater crossing portion 15. That is, a part of the microwave can be separated toward the object 2 to be heated by diffraction and scattering of the microwave generated around the heater 5. This makes it possible to more uniformly propagate the microwave through the entire waveguide path in the heating chamber 1, thereby efficiently heating the object 2.

As shown in fig. 2, the heater 5 is connected to an external power supply 20 via a lead-out portion 19 provided on a wall surface (in the present embodiment, a rear wall surface 1b (see fig. 3)) of the heating chamber 1. The lead portion 19 is disposed outside the antenna projection space 7. In the present embodiment, no structure that impedes propagation of microwaves is provided near the end of the space between the plane formed by the heater 5 and the ceiling portion 1 a. This ensures a waveguide path and allows the microwave to propagate over a wide range.

In the present embodiment, two antennas 4 are disposed so that the annular plane 4a is along a straight line Y which is a center line of the heating chamber 1 in the depth direction. That is, the two antennas 4 are disposed in the middle between the two opposing wall surfaces of the heating chamber 1. In the present embodiment, the two wall surfaces are the rear wall surface 1b of the heating chamber 1 and the inner wall surface of the door 21 covering the front opening of the heating chamber 1 (see fig. 3).

The electromagnetic field excitation 9 of the antenna 4 of the loop antenna configuration propagates from the loop plane 4a in two directions (direction 9a, direction 9b) perpendicular to the loop plane 4 a. According to the present embodiment, the microwave can be uniformly propagated over a wide range. As a result, the object 2 can be heated more uniformly.

The antenna projection spaces 7 of the two antennas 4 do not overlap in the heating chamber 1. According to the present embodiment, the microwaves radiated from the two antennas 4 do not interfere with each other, and thus the microwaves can be propagated to the respective corners of the heating chamber 1.

(embodiment mode 2)

Fig. 4 is an enlarged view of the upper part of the heating chamber 1 in the microwave processing apparatus 50 according to embodiment 2 of the present invention.

As shown in fig. 4, in the present embodiment, the antenna 4 of the loop antenna structure is configured such that the antenna center portion 14, which is the center portion of the loop, is located in a space between the plane formed by the heater 5 and the ceiling portion 1a of the heating chamber 1. With this configuration, most of the microwaves radiated from the antenna 4 can be efficiently propagated through the space between the plane formed by the heater 5 and the ceiling portion 1 a.

In the present embodiment, the distance between the antenna 4 and the ceiling portion 1a is set to be 2 times or less the distance between the heater 5 and the ceiling portion 1 a. More specifically, the distance 16 between the ceiling portion 1a and the portion of the antenna 4 farthest from the ceiling portion 1a is set to 2 times or less the distance 17 between the ceiling portion 1a and the portion of the heater 5 farthest from the ceiling portion 1 a.

Thereby, the antenna center portion 14 can be disposed in the waveguide formed by the heater 5 and the ceiling portion 1 a. As a result, most of the microwaves excited by the antenna 4 can be guided to the waveguide, and efficient heating can be achieved.

Generally, in order to prevent the top portion 1a from being deformed by thermal expansion or the like, the top portion 1a is partially provided with irregularities or an inclined surface 11. Since the inclined surface 11 is a portion that absorbs deformation and is unstable, the antenna 4 is disposed on the flat portion 12 of the ceiling portion 1a in the present embodiment.

As shown in fig. 4, a connecting portion 18a is provided at the top portion 1 a. In the present embodiment, the coaxial line 18 is the transmission line 6. The coaxial line 18 is connected to the oscillator 3, and transmits the microwave generated in the oscillator 3 to the antenna 4 via the connection 18 a.

One end of the antenna 4 is connected to the coaxial line 18 via a connection portion 18 a. The other end of the antenna 4 is connected to the top portion 1a via a ground portion 13 and grounded. In the present embodiment, the ground portion 13 is provided at a distance of within one quarter of the wavelength of the microwave from the connection portion 18 a. The reason for this is shown below.

When the ground portion 13 is disposed apart from the connection portion 18a, the antenna 4 reaches not only a space below the flat portion 12 but also a space below the inclined surface 11. In this case, the stability of the radiation performance of the antenna 4 is impaired. The high-frequency current flowing from antenna 4 to ground 13 returns to the outer-skin ground of coaxial line 18 via top portion 1 a. The electromagnetic field excitation due to the high-frequency current flowing in the top portion 1a causes deviation in the radiation performance of the intended antenna 4.

However, in the present embodiment, the distance between the connection portion 18a and the ground portion 13 is set to be within one quarter of the wavelength of the microwave. This eliminates the problems of stability and deviation of the radiation performance of the antenna 4, and realizes efficient heating. This is because it is preferable that the distance between the connection portion 18a through which the high-frequency current flows and the ground portion 13 is short.

In the present embodiment, the antenna 4 has the annular side 4b arranged substantially parallel to the inclined surface 11 of the heating chamber 1. When a high-frequency current flows in the antenna 4 in the vicinity of the wall of the ceiling portion 1a in this way, an electromagnetic field generated between the antenna 4 and the ceiling portion 1a affects the radiation performance of the antenna 4.

In the present embodiment, by providing a space having a substantially uniform thickness between the antenna 4 and the ceiling portion 1a, the electromagnetic field distribution between the annular edge 4b of the antenna 4 and the ceiling portion 1a can be made more uniform. Thereby, the influence of the loop antenna on the electromagnetic field excitation can be suppressed. As a result, good radiation performance of the antenna 4 can be obtained.

As described above, the microwave processing device 50 according to the present embodiment uses the space between the heater 5 and the ceiling portion 1a of the heating chamber 1 as a waveguide. Thereby, the antenna 4 can radiate microwaves to the entire heating chamber 1. As a result, the heating performance of the heater and the heating performance of the microwave can be ensured at the same time by using a small antenna.

The microwave processing apparatus according to the present invention is explained using the above embodiments. However, the present invention is not limited thereto. For example, in the present embodiment, the oscillator for the microwave is made of a semiconductor. However, other oscillators such as magnetrons may be used. In this embodiment, the antenna is a loop antenna. However, other configurations of antennas may be used.

Industrial applicability

The present invention can be applied to a heating device using medium heating, a kitchen waste disposer, and the like.

Description of the reference symbols

1. 105: a heating chamber; 1a, 105 a: a top portion; 1 b: a rear wall surface; 2: an object to be heated; 3. 103: an oscillating unit; 4: an antenna; 5. 102: a heater; 6: a transmission line; 6a, 18 a: a connecting portion; 7: an antenna projection space; 8: a holder; 9: exciting by an electromagnetic field; 9a, 9 b: direction; 10: an arrow; 11: an inclined surface; 12: a flat portion; 13: a ground part; 14: an antenna center section; 15: a heater crossing portion; 16. 17: a distance; 18: a coaxial line; 19: a lead-out section; 20: an external power supply; 21: a door; 50. 100, and (2) a step of: a microwave processing device; 101: an irradiation region; 104: a radiation part.

Claims

1. A microwave processing device is provided with:

a heating chamber configured to accommodate an object to be heated;

an oscillation unit configured to generate microwaves;

a heater disposed in the heating chamber so as to form a plane facing a wall surface of the heating chamber and spaced apart from the wall surface by a predetermined distance; and

a radiation unit disposed in the heating chamber and configured to radiate the microwave into a space between the heater and the wall surface so that the microwave propagates through the space between the heater and the wall surface,

the radiation unit is a loop antenna having a loop plane perpendicular to the wall surface, the center of the loop plane is located in the space between the heater and the wall surface, and the microwave radiated by the radiation unit propagates through an antenna projection space that includes the loop plane and extends perpendicular to the loop plane.

2. The microwave processing apparatus according to claim 1,

the distance between the wall surface and the portion of the radiation part farthest from the wall surface is 2 times or less the distance between the wall surface and the portion of the heater farthest from the wall surface.

3. The microwave processing apparatus according to claim 1,

the heater traverses the antenna projection space at a plurality of positions.

4. The microwave processing apparatus according to claim 1,

the antenna projection space extends from the annular plane in two directions perpendicular to the annular plane.

5. The microwave processing apparatus according to claim 1,

the heating chamber has a holder for holding the heater, and the holder is disposed outside the antenna projection space.

6. The microwave processing apparatus according to claim 1,

the heating chamber has a lead-out portion for connecting the heater to an external power supply, and the lead-out portion is disposed outside the antenna projection space.

7. The microwave processing apparatus according to claim 1,

the radiation section is disposed between two wall surfaces of the heating chamber facing each other.

8. The microwave processing apparatus according to claim 1,

the microwave processing apparatus further includes a transmission unit connected to the oscillation unit and configured to transmit the microwave to the radiation unit, wherein one end of the loop antenna is connected to the transmission unit via a connection unit provided on the wall surface, the other end of the loop antenna is connected to the wall surface via a ground unit, and the ground unit is spaced apart from the connection unit by a distance of not more than one quarter of the wavelength of the microwave.

9. The microwave processing apparatus according to claim 1,

the radiation portion has an annular edge arranged in parallel with the wall surface.

10. The microwave processing apparatus according to claim 1,

the radiation unit includes a plurality of loop antennas, and the antenna projection spaces of the loop antennas do not overlap each other in the heating chamber.

11. The microwave processing apparatus according to claim 1,

the wall surface is a ceiling of the heating chamber.