JP2531854B2 - Microwave power supply - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a microwave feeding unit used in a high frequency heating apparatus for introducing microwaves into a microwave processing chamber.

[Conventional technology]

Conventionally, a shielding plate that shields the microwave processing chamber from a waveguide forming a microwave power feeding portion of a high-frequency heating apparatus using microwaves is inside a microwave processing chamber (sheet metal) via a cushioning material. It is fixed by screwing it to. The shield plate shields the waveguide in which the magnetron is installed and the microwave processing chamber, and protects the magnetron antenna from combustible gas and water vapor generated in the microwave processing chamber.

A conventional microwave power feeding unit is shown in FIGS. 2 and 3 (a).
Description will be made based on (c).

FIG. 2 is a cross-sectional view showing the configuration of a conventional high-frequency heating device having a microwave power feeding section.

In FIG. 2, 1 is an inner container, 2 is an outer container, 3 is a primary combustion chamber serving as a microwave processing chamber, 4 is a lid constituting the primary combustion chamber 3, 6 is an outer container, 7X is an internal waveguide, 7a is a communication hole provided in the internal waveguide 7X, 8 is an external waveguide, 9 is a magnetron for generating microwaves, 10 is a nozzle, 11 is a secondary combustion chamber, 12 is an upper shielding plate, and 13X is a buffer. Material, 14X is a lower shielding plate, 15 is a mounting bracket, 16 is an air supply pipe for supplying air, 17 is a combustion cylinder, 18 is an incineration object to be heated,
Reference numeral 19 is a heat insulating space partition plate, 19a is an orifice, 20 is an upper heat insulating space chamber, 21 is a lower heat insulating space chamber, 22 is a regulating valve, 23 is a communicating pipe, and 24 is a heat insulating material provided on the lower surface of the lid 3.

The arrow A indicates the air supplied into the outer container 2 and the inner container 1 by the air supply pipe 16, and the double arrow B indicates the primary combustion chamber 3.
Combustible gas and water vapor generated inside, Q indicates a conventional microwave power feeding unit.

FIG. 3 (a) is a vertical cross-sectional view showing the structure of a conventional microwave feeding part, FIG. 3 (b) is a bottom view showing the structure of the same microwave feeding part, and FIG. 3 (c) is FIG. It is an enlarged view of the Y section shown to (a).

In FIGS. 3 (a) to 3 (c), the same reference numerals as those in FIG. 2 denote the same parts.

As shown in FIGS. 2 and 3 (a) to (c), the microwave feeding part Q includes a magnetron 9, an external waveguide 8, an internal waveguide 7X, a buffer material 13X, an upper shielding plate 12, It is composed of a lower shield plate 14 and a mounting bracket 15.

The magnetron 9 is provided in the external waveguide 8. An outer shield plate 12 shields a space between the outer waveguide 8 and the inner waveguide 7X, and the outer shield plate 12 is mounted between the outer container 6 and the outer waveguide 8. Further, a space between the internal waveguide 7X and the primary combustion chamber 3 is shielded by an internal shielding plate 14, and the internal shielding plate 14 is buffered inside the lid 4 constituting the primary combustion chamber 3 by a mounting member 15. It is fixed with screws via the material 13X. The mounting member 15 is electrically connected to the lid 3. Further, the cushioning material 13X is for maintaining elasticity between the lower shield plate 14 and the mounting member 15 or between the lower shield plate 14 and the lid 3.

In the conventional high-frequency heating apparatus having the microwave feeding portion configured as described above, the microwave is generated by the magnetron 9, and the microwave is generated from the external waveguide 8 to the upper shield plate 12 and the internal waveguide 7X. It is propagated to the inner and lower shielding plates 14 and further to the incineration object 18 in the primary combustion chamber 4. As a result, the incineration object 18 is heated and incinerated. At this time, combustible gas and water vapor B are generated in the primary combustion chamber 4.

[Problems to be Solved by the Invention]

However, in the conventional microwave power feeding part Q configured as described above, the combustible gas and the water vapor B generated in the primary combustion chamber 3 are formed on the lower surface of the lower shielding plate 14X and the cushioning material 13X.
By adhering to and penetrating into, the lower shield plate 14X and the cushioning material 13X themselves cause microwave absorption and discharge, which causes a rapid heating phenomenon in the lower shield board 14X itself and deteriorates the cushioning material 13X. .

In this way, a sudden heating phenomenon occurs in the lower shield plate 14X, and the cushioning material 13X deteriorates and loses its cushioning property and airtightness, so that the lower shield plate 14X is distorted and cracked.
There is a problem that a bad smell is emitted from the mounting portion of the external waveguide 8 due to deterioration of the shield against the combustible gas and water vapor generated in the primary combustion chamber 3. In addition, cushioning material
There is a problem that flammable gas and water vapor enter the external waveguide 8 due to deterioration of 13X or breakage of the shielding plate 14X, and discharge is generated in the internal waveguide 7X and the external waveguide 8.

Further, microwaves used for other than the heating phenomenon of the lower shield plate 14X propagate to the incineration object 18 in the primary combustion chamber 3, but the supply of microwaves to the incineration object 18 becomes unstable, and as a result, There was a problem that the drying time of the incineration object 18 was extended, the combustion time was extended, and the ashing rate decreased.

In view of the above problems, an object of the present invention is to prevent distortion and breakage of a shield plate for shielding between a waveguide for introducing microwaves and a microwave processing chamber, and to prevent microwaves from being transmitted from the waveguide. An object of the present invention is to provide a microwave supply unit that can stably supply microwaves to the wave processing chamber.

[Means for solving the problem]

The microwave feeding part of the present invention includes a waveguide, a shield plate receiving fitting, a shield plate, and a shield mounting fitting.

The waveguide is inserted into the microwave processing chamber in which the object to be heated is placed and is for introducing microwaves. The shield plate metal fitting is a ring-shaped member that is in contact with the inside of the microwave processing chamber via a gasket outside the waveguide, has an inner flange at the upper end, and has a female screw inside the lower end. Is. The shield plate is a cup-shaped member having an opening end portion abutting on the lower surface of the inner flange of the shield plate bracket via a cushioning material and having an outer flange at the opening end portion. The shield plate mounting bracket has an upper end abutting on the lower surface of the outer flange of the shield plate through a gasket, and an upper surface of the outer flange abutting the lower end of the shield plate bracket on the outside of the upper end. The male screw is a ring-shaped screwed to the female screw of the shield plate bracket.

[Action]

According to the configuration of the present invention, between the inside of the microwave processing chamber and the shield plate bracket, between the shield plate and the shield plate mount,
The gasket and the cushioning material provided between the shielding plate receiving metal member and the shielding plate mounting metal member and between the shielding plate and the shielding plate metal receiving member can improve the airtightness of the waveguide with respect to the waveguide. Further, in order to prevent the shield plate from being damaged, the cushioning material provided between the shield plate and the shield plate bracket does not come into contact with the atmosphere in the microwave processing chamber. Therefore,
The deterioration of the cushioning material can be prevented, and good cushioning property and airtightness can be secured. Further, by making the shape of the shield plate cup-shaped, the surface of the shield plate in the microwave processing chamber becomes an oxidizing high temperature atmosphere, whereby the combustible gas and water vapor adhering to the shield plate can be removed well.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 1 (a) to (c) and FIG.

FIG. 1 (a) is a vertical cross-sectional view showing the structure of the main part of the microwave feeding part according to one embodiment of the present invention, and FIG. 1 (b) is a bottom view showing the structure of the main part of the microwave feeding part. , Fig. 1 (c) is an enlarged view of the X portion of Fig. 1 (a).

In FIGS. 1A to 1C, 3 is a primary combustion chamber that serves as a microwave processing chamber, 4 is a lid that forms the primary combustion chamber 3,
Reference numeral 7 is an internal waveguide inserted into the primary combustion chamber 3 serving as a waveguide inserted in the microwave processing chamber, 13 is a cushioning material, and 14 is a cup-like shape having an outer flange 14b at an opening end 14a serving as a shielding plate. Lower shield plate, 15a is a shield plate receiving metal fitting, a ring-shaped lower shield plate receiving metal fitting having an inner flange 15c at the upper end and a female screw 15d inside the lower end, and 15b is a shield mounting material A ring-shaped lower shield mounting member having an outer flange 15e on the lower end and a male screw 15f on the outer side of the upper end, and 26 are gaskets.

The cushioning material 13 has high temperature resistance. gasket
26 has high temperature resistance and good airtightness.
The material of the lower shield plate 14 is less likely to allow infiltration of combustible gas and water vapor (good penetration resistance), has no deformation, cracking or alteration due to heat (good heat resistance), and has no alteration due to acidity or alkalinity at high temperature ( Good acid and alkali resistance),
It has good microwave transparency.

The position of the weak electric field of the microwave is located away from the lower open end of the internal waveguide 7, and the lower shield plate is located at this position.
The 14 underside positions are relevant.

The structure of the high-frequency heating apparatus having the microwave feeding section shown in FIGS. 1 (a) to (c) is the same as that of the high-frequency heating apparatus shown in FIG. 2 except for the conventional microwave feeding section Q. Is.

As shown in FIGS. 1 (a) to 1 (c), the microwave feeding part is composed of a magnetron 9, an external waveguide 8, an internal waveguide 7, an upper shield plate 12, a lower shield plate bracket 15a, and a lower shield. Plate mounting bracket 15b,
It is composed of a gasket 26, a cushioning material 13, and a lower shield plate 14.

The lower shielding plate receiving metal fitting 15a is brought into contact with the lid 4 inside the primary combustion chamber 3 via the gasket 26 outside the internal waveguide 7. The lower shield plate 14 is an inner flange 15c of the shield plate bracket 15a.
The opening end 14a is brought into contact with the lower surface of the through the cushioning material 13.
The shield plate mounting bracket 15b has its upper end abutted on the lower surface of the outer flange 14b of the lower shield plate 14 via a gasket 26, and the upper surface of the outer flange 15e on the lower end of the shield plate bracket 15c via a gasket 26. Abut. Then, the shielding plate mounting bracket 15b is rotated by the screw mounting hole 100, and the shielding plate mounting bracket 15b is rotated.
The lower shield plate 14 is fixed to the inside of the primary combustion chamber 3 by screwing the male screw 15f of the above into the female screw 15d of the lower shield plate receiving metal fitting 15c, and the internal waveguide 7 is fixed by the cup-shaped lower shield plate 14. Siege.

With this structure, the cushioning material 13 provided at the opening end 14a of the lower shielding plate 14 does not come into contact with the atmosphere in the primary combustion chamber 3. Further, by attaching and detaching the lower shielding plate 14 by screwing the lower shielding plate receiving metal fitting 15c and the lower shielding plate mounting metal fitting 15e, the lower shielding plate 14 can be easily attached and detached,
In addition, the lower shield plate 14 can be reliably attached.

The operation of the high-frequency heating device having the microwave power feeding unit configured as described above will be described below.

Microwaves generated by the magnetron 9 propagate from the external waveguide 8 to the upper shield plate 12, the inner waveguide 7 and the lower shield plate 14, and further to the incineration object 18 arranged in the primary combustion chamber 4. Propagate. As a result, the incineration object 18 is heated and combustible gas and steam are generated in the primary combustion chamber 4.

At this time, the combustible gas and water vapor generated in the primary combustion chamber 3 are discharged between the lower shield plate 14 and the lower shield plate mounting bracket 15b, between the lower shield plate receiving bracket 15a and the lower shield plate mounting bracket 15b, and in the lower portion. A gasket which attempts to pass between the shield plate receiving metal fitting 15a and the lid 3 forming the primary combustion chamber 3 and between the lower shield plate receiving metal fitting 15a and the lower shield plate 14, but which has high temperature resistance and airtightness. Blocked by 26 and cushioning material 13. This completely prevents invasion of combustible gas and water vapor into the internal waveguide 7. In addition, the opening end of the lower shield plate 14
The cushioning material 13 provided on 14a is a gasket 26 having excellent airtightness provided between the lower shielding plate 14 and the lower shielding plate mounting bracket 15b and between the lower shielding plate mounting bracket 15b and the lower shielding plate receiving bracket 15a. As a result, since the atmosphere inside the primary combustion chamber 3 is not touched, deterioration of the cushioning material 13 can be prevented, and good cushioning properties and airtightness can be secured. Therefore, the thermal stress applied to the lower shielding plate 14 can be favorably absorbed by the buffer material 13, and the distortion and cracking of the lower shielding plate 14 can be prevented.

Further, by making the shape of the lower shield plate 14 into a cup shape, the surface near the lower shield plate 14 in the primary combustion chamber 3 becomes an oxidizing high temperature atmosphere, which causes the surface of the lower shield plate 14 and the lower shield plate fitting 15b. The combustible gas and water vapor adhering to the are well removed by the combustion heat of the incineration object 18 in the primary combustion chamber 3 serving as the microwave processing chamber, the self-heating of the lower shielding plate 14 and the oxidation reaction caused by the air. Therefore, the absorption of microwaves by the water vapor and the combustible gas attached to the lower shield plate 14 can be reduced. This allows
Microwaves can be stably supplied from the internal waveguide 7 into the primary combustion chamber 3, and a microwave supply unit with improved processing efficiency for the incineration object 18 can be obtained.

The lower surface of the lower shield plate 14 is located in the weak electric field of microwaves. As a result, the lower shield plate 14 by the microwave is
Prevents rapid heating of itself.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to the microwave feeding part of this invention, the waveguide inserted in the microwave processing chamber in which the object to be heated is placed is abutted to the inside of the microwave processing chamber on the outside of this waveguide via the gasket. , A ring-shaped shield plate bracket having an inner flange at the upper end and a female screw inside the lower end, and the opening end abuts on the lower surface of the inner flange of this shield plate bracket through a cushioning material The cup-shaped shield plate having an outer flange at the opening end and the upper end of the outer flange of the shield plate are brought into contact with the lower surface of the shield plate via a gasket. Since the upper surface is abutted through the gasket and the male screw outside the upper end is provided with the ring-shaped shield plate mounting bracket screwed to the female screw of the shield plate receiving bracket, The airtightness of the wave tube is improved by the shield plate. It is possible to prevent the deterioration of the cushioning material. Further, the shape of the shielding plate is cup-shaped, and the surface of the shielding plate is in an oxidizing high temperature atmosphere, so that the combustible gas, water vapor and the like adhering to the surface of the shielding plate can be satisfactorily removed.

As a result, distortion and cracking of the shield plate can be reliably prevented, and microwaves can be stably supplied from the waveguide into the microwave processing chamber, so that the efficiency of microwave processing of the object to be heated can be improved. It is possible to obtain a microwave power feeding section with improved power consumption.

[Brief description of drawings]

FIG. 1 (a) is a vertical cross-sectional view showing the structure of the main part of the microwave feeding part according to one embodiment of the present invention, and FIG. 1 (b) is a bottom view showing the structure of the main part of the microwave feeding part. FIG. 1 (c) is an enlarged view of part X in FIG. 1 (a), FIG. 2 is a sectional view showing the configuration of a conventional high-frequency heating device having a microwave feeding part, and FIG. 3 (a). Is a vertical cross-sectional view showing the structure of a conventional microwave feeding part, FIG. 3 (b) is a bottom view showing the structure of the same microwave feeding part, and FIG. 3 (c) is Y shown in FIG. 3 (a). It is an enlarged view of a part. 3 ... Primary combustion chamber (microwave processing chamber), 7 ... Internal waveguide (waveguide), 13 ... Buffer material, 14 ... Lower shield plate (shield plate), 14a ... Open end, 14b ... Outer flange, 15a ...
… Lower shield plate bracket (shield plate bracket), 15b… Lower shield plate bracket (shield plate bracket), 15c… Inner flange, 15d… Female screw, 15e… Outer flange, 15f… Male Screw, 18 …… Incinerator (object to be heated), 26 …… Gasket

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Keiichi Iwabuchi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-2-302507 (JP, A)

Claims (1)

(57) [Claims] 1. A waveguide inserted into a microwave processing chamber in which an object to be heated is placed, and a waveguide is abutted on the outside of the waveguide to the inside of the microwave processing chamber via a gasket, and is attached to the upper end of the waveguide. A ring-shaped shielding plate receiving metal fitting having an inner flange and a female screw inside the lower end portion, and an opening end portion is abutted to the lower surface of the inner flange of the shielding plate receiving metal fitting via a cushioning material, A cup-shaped shielding plate having an outer flange at its end, an upper end abutting on the lower surface of the outer flange of the shielding plate via a gasket, and an upper surface of the outer flange at the lower end of the shielding plate receiving bracket. And a ring-shaped shield plate mounting bracket in which a male screw outside the upper end is screwed to a female screw of the shield plate receiving bracket.