JPH0665158B2 - Microwave melting equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a microwave melting device for melting a liquid material, a powdery material, a lump, or a mixture thereof by microwave,
In particular, the present invention relates to a microwave melting apparatus suitable for melting radioactive incineration ash, sludge, etc. by microwaves to form a uniform melt.

[Conventional technology]

The method of melting and solidifying radioactive waste such as liquid, powder and lump is
Various studies and proposals have been made with the increase in these wastes. Among them, the microwave melting device can be melted in a short time, the radioactive contamination control is easy, the number of devices installed in the radioactive contamination area is small, and the number of moving parts is small. It has advantages such as easy things.

The principle structure of a conventional microwave melting device is shown in FIG. In the figure, 10 is a microwave inlet for introducing microwaves from a microwave oscillating device (not shown), 11 is a partition window, 12 is a resonant cavity, 13 is a matching mechanism for resonating the melting device, and 14 is an object to be heated. Input slot, 1
Reference numeral 5 is an outlet for discharging decomposed gas of the object to be heated, 16 is a melting furnace, 17 is a flange connecting the resonance cavity portion 12 and the melting furnace 16, and 18 is an object to be heated.

In this conventional microwave melting device, the material to be melted is
When heated with either E ₁ or TM ₁₁ resonant modes, the melt is not entirely melted, resulting in an incomplete melt. That is, in the resonance mode of TE ₁₀ , a high temperature portion appears in the central portion of the heating container along the axial direction of the waveguide, and both sides thereof are low temperature portions. In addition, the resonance mode is T
In the case of M ₁₁ , the inner peripheral edge portion of the heating container has a high temperature and the central portion has a low temperature. For this reason, when the TE ₁₀ mode is used for heating, an unmelted portion is formed in the peripheral portion, and when the TM ₁₁ mode is used for heating, an unmelted portion is generated in the central portion. As a result, when the material to be melted is cooled and solidified, the incompletely melted portion remains as powder or particles,
There is a possibility that a portion that has not been melted when cooled and solidified may flow out.

Therefore, in the conventional apparatus of this type, in order to equalize the heating temperature of the heated object, as a microwave field pattern of the melting furnace 16, uses a point symmetric TM ₀₁ mode generally, in TM ₀₁ mode The adjustment for resonating is performed by moving the matching mechanism 13 up and down.

[Problems to be solved by the invention]

However, in the conventional microwave melting device,
When the melting height of the object to be heated is changed or the height of the object to be heated changes and the height of the object to be heated changes, the microwave resonance mode propagating in the melting furnace 16 becomes the TE ₁₁ mode. It has a drawback that it cannot be heated uniformly.

Further, in the conventional microwave melting apparatus, the discharge port 15 for discharging the decomposition gas of the object to be heated 18 into the resonance cavity portion 12.
Since the object to be heated and the object inlet 14 are provided, the electric field is disturbed in the vicinity thereof, and the resonance mode is TE rather than the TM ₀₁ mode.
_It has a drawback that ₁₁ modes are likely to occur.

Further, in the conventional microwave melting apparatus, the matching mechanism 13 is moved to bring the melting furnace 16 into a resonance state to heat the object to be heated 18. However, it does not necessarily resonate in the TM ₀₁ mode, but in the TE ₁₁ mode. It has the drawback that it may resonate.

[Object of the Invention]

An object of the present invention is to provide a microwave melting device capable of uniformly heating an object to be heated by constantly resonating the melting furnace in TM ₀₁ mode.

[Means for solving problems]

The TE ₁₁ mode has an electric field in a direction perpendicular to the microwave traveling direction, and the TM ₀₁ mode has an electric field parallel to the microwave traveling direction. The present invention attenuates the TE ₁₁ mode without affecting the TM ₀₁ mode by short-circuiting and removing the electric field perpendicular to the traveling direction of the microwave, and the object to be heated in the furnace is removed only by the TM ₀₁ mode. The idea is to heat it uniformly.

That is, the present invention provides a resonance cavity portion having a microwave introduction port and a matching mechanism, one end of which is open, a melting furnace which is connected to an open end of the resonance cavity portion and accommodates an object to be heated, and the melting furnace. In the thing provided with the to-be-heated object input port for injecting the to-be-heated object, and the gas discharge port for discharging the decomposition gas of the to-be-heated object It is characterized in that a short-circuiting member for short-circuiting and removing an electric field in a direction perpendicular to the direction is provided.

According to the present invention having such a configuration, the T
Since only M ₀₁ mode is transmitted, the matching mechanism is TM
It can be fixed in the most comfortable position for ₀₁ mode, and no maintenance is required.

Further, according to the present invention, a matching device for resonating the melting furnace can be attached to the oscillator side of the partition window, which facilitates maintenance and inspection, especially when the object to be heated contains a radioactive substance, etc. Since the melting furnace side is isolated from the partition window, no one can enter it, and objects requiring maintenance can be installed closer to the oscillator side than the partition window, facilitating maintenance.

〔Example〕

 Examples of the present invention are shown below.

FIG. 1 shows an embodiment of the present invention.

In the figure, 1 is a microwave inlet for introducing microwaves from a microwave oscillator, 2 is a resonant cavity, 3 is a matching mechanism for resonating the melting device, 4 is an inlet for a heated object, and 5 is a target. An outlet for discharging decomposed gas of the heated material, 6 a melting furnace, 7 a flange connecting the resonance cavity 2 and the melting furnace 6, 8 a heated object, 9 a partition window, and 20 a matching unit.

This embodiment is different from the conventional example shown in FIG.
The point is that a short-circuit member 30 for short-circuiting an electric field perpendicular to the microwave traveling direction so as to be perpendicular to the longitudinal direction is provided inside. The short-circuit member 30 is provided in the resonance cavity portion 2 below the heating target inlet 4.
The installation position of the short-circuit member 30 does not necessarily have to be lower than the object-to-be-heated inlet 4 and may be provided in the resonance cavity portion 2. However, it is preferably provided below the object-to-be-heated inlet 4. Most effective.

The specific structure of the short-circuit member 30 is shown in FIG. In FIG. 2A, the metal rod 31 is provided in the resonance cavity portion 2. 2 (B) is the metal rod 3 shown in FIG. 2 (A).
Two 1s are provided so as to be orthogonal to each other. FIG. 2 (C) shows a metal member 32 formed by bending a metal rod into a V shape at the center. Further, FIG. 2 (D) shows a metal member 33 in which the central portion of the metal rod is formed into a rhombus shape,
The metal mesh 34 is shown in FIG. 2 (E).

〔The invention's effect〕

As described above, according to the present invention, since the short-circuit member is provided at a right angle to the traveling direction of the microwave, TE
₁₁ modes can be removed and the inside of the melting furnace can be heated uniformly.

Further, according to the present invention, since only the TM ₀₁ mode is transmitted into the melting furnace, the fixed position of the matching mechanism can be fixed to a specific position.

Further, according to the present invention, since the matching device for resonating the melting furnace is attached to the oscillator side of the partition window, maintenance and inspection can be facilitated. In particular, if the object to be heated contains a radioactive substance, the melting furnace side is isolated from the partition window and no one can enter, so that the one that needs maintenance can be installed on the oscillator side from this partition window.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a concrete configuration diagram of the short-circuiting member shown in FIG. 1, and FIG. 3 is a configuration diagram of a conventional microwave melting device. 1 ... Microwave inlet, 2 ... Resonant cavity, 3 ... Matching mechanism, 4 ... Heated object inlet, 5 ... Exhaust port, 6 ... Melting furnace, 8 ... Heated object, 9 ... ... Partition window, 30 ... Short-circuit member.

Claims (3)

[Claims] 1. A resonance cavity part having a microwave introduction port and a matching mechanism, one end of which is open, a melting furnace which is connected to the open end of the resonance cavity part and accommodates an object to be heated, and the inside of the melting furnace. In which a heated object charging port for charging a heated object and a gas discharging port for discharging a decomposition gas of the heated object are provided. Inside the electric field of the microwave in the resonant cavity, the traveling direction in the melting furnace A microwave melting device, wherein a short-circuiting member for short-circuiting and removing an electric field in a direction perpendicular to is provided. 2. The microcircuit according to claim 1, wherein the short-circuiting member is provided in a cavity of the resonance cavity below a position where a material to be heated inlet is installed. Wave melting device. 3. The microwave melting apparatus according to claim 1 or 2, wherein a partition window is provided at the microwave introduction port.