JPH0345113Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a microwave melting furnace that reliably prevents dust and fume from entering the waveguide and head tuner.

(Prior art) Conventionally, in a microwave melting furnace, as shown in FIG. The head tuner 3 is movably penetrated through the head tuner 3 and is configured to be movable up and down. A sleeve made of Teflon or the like is disposed within the guide portion 31 so that the shaft 30 can move smoothly. Further, a waveguide 4 is provided on the side of the upper part of the main body, and an exhaust pipe 5 is attached to the lower side of the waveguide 4.
This exhaust pipe 5 is connected to a suction fan (not shown). Furthermore, a feeder 7 whose one end is connected to a hopper 6 for processing objects is connected to the main body 1.

In the above configuration, from the hopper 6 to the feeder 7
The object to be processed is supplied into the crucible 2 through the waveguide 4, and the object to be processed in the crucible 2 is irradiated with microwaves through the waveguide 4, thereby heating and melting the object. The microwaves within the microwave melting furnace main body 1 are adjusted by moving the head tuner 3 up and down. The material to be processed in the crucible 2 is melted by suctioning microwaves, and decomposed gases (off gases) such as water vapor, sulfur dioxide gas, chlorine gas, and so-called smoke are generated depending on the properties and chemical composition of the material to be processed. In addition, when the processed material is newly supplied to the molten material in the crucible 2, dust components such as fine powder of the processed material scattered or components vaporized by heating and melting come into contact with cold air and react to form fine particles. A gas called fume, such as zinc oxide, which has changed into a solid component, is generated in the furnace.

Part of the decomposed gas and the dust and fume accompanying the decomposed gas are exhausted from the exhaust pipe 5 as shown by arrow A in FIG. The remainder rises inside the furnace and adheres to the inner wall of the main body 1, the head tuner, and the waveguide 4, and a large amount of this will accumulate during long-term operation. When such deposits occur, discharge phenomena are likely to occur using the deposits as discharge points, and the deposits on the head tuner portion may get caught in the sleeve mechanism.
Making it difficult to move the head tuner 3 smoothly, etc.
Operational troubles will occur.

To solve this problem, as shown in Figure 5,
An intake pipe 50 is provided in the main body 1 at a position facing the exhaust pipe 5, and air flows from there toward the exhaust pipe 5 to form an air curtain B to block the rising airflow A. However, the diameter of this suction pipe 50 cannot be made very large because of the need to prevent microwave leakage, and therefore, as shown in FIG. The rising air current A blows through the space (gap) C on both sides. especially
Compared to a melting furnace that uses microwaves with a short wavelength such as 2450MHz, in a melting furnace that uses microwaves with a long wavelength such as 915MHz, the diameter of the intake pipe 50 is smaller than the diameter of the main body 1. The atrium gets bigger.

Furthermore, in the configuration shown in FIG. 5, a fan 42 is used to blow air into the furnace in order to protect the Teflon partition plate 41 of the waveguide 4, but this air flow D also blows air into the furnace. The entire surface cannot be covered, and the result is similar to that of the air curtain B described above. Further, even if the air flow D and the air curtain B are combined, it is not possible to cover the entire inside of the furnace, which is the same as above.

(Purpose of the invention) This invention was made to eliminate such conventional drawbacks, and is to reliably prevent dust and fume from entering the head tuner section and the waveguide with a simple configuration. This provides a structure that allows for

(Structure of the device) This device supplies a material to be processed into a crucible, irradiates it with microwaves to melt the material, and draws air from an intake port to discharge off-gas. In a melting furnace, a head tuner is arranged in the upper part of the furnace body so that it can be raised and lowered, a substantially uniform gap is formed between the outer periphery of the head tuner and the inner surface of the furnace body, and an air suction port is formed in the furnace body above the head tuner. This is what I did. In this way, by introducing air into the furnace from the air intake port on the upper side of the head tuner through the outer periphery of the head tuner, a downward air current is formed all over the inside of the furnace, thereby preventing the generation of an upward air flow containing dust and fume. That's what I do.

(Example) In FIGS. 1 and 2, a guide section 31 and its flange 33 are attached to the upper end of the furnace body 1, and the opening diameter of the guide section 31 is set to be below the cutoff wavelength of the microwave. A large number of air intake ports 35 are formed substantially uniformly in the circumferential direction in the surrounding flange portion 33 . The shaft 30 of the head tuner 3 movably passes through the guide part 31, and the guide part 30 is arranged so that a uniform gap is always formed between the outer peripheral surface of the head tuner 3 and the inner peripheral surface of the main body 1.
1, the shaft 30 is held so as not to be eccentric. Furthermore, an air suction port 44 is formed in the waveguide 4 . Note that the air intake port 35 is connected to the flange portion 33.
Instead of being formed in the head tuner 3, it may be formed in the furnace body 1 above the head tuner 3.

In the above configuration, dust and fume generated by heating and melting the object to be processed are sucked into the exhaust pipe 5 as shown in the figure along with the upward airflow A, and air sucked from the air intake port 35 is sucked into the head tuner 3.
A downward airflow E spreads from the gap around the furnace to the entire surface of the furnace.
The air is sucked into the exhaust pipe 5 along with the rising air current A. The downdraft E has an inlet 44 of the waveguide 4.
This includes air sucked in from the The downdraft E spreads over the entire surface of the furnace, and since there is no air curtain gap C as in the conventional structure, the updraft A containing dust and fume is all sucked into the exhaust pipe 5 and rises further upwards. This will definitely be prevented. In particular, since air is descending at a high speed in the gap around the outer periphery of the head tuner 3, upward flow from this area is reliably blocked.

FIG. 3 shows another embodiment of this invention, in which a pipe 80 is connected to the upper part of the furnace body 1 and the waveguide 4 to an air inlet, and a fan 8 is connected to the other end of the pipe 80. A filter 9 is further provided at the tip thereof. As this filter 9, it is preferable to use a high performance filter such as a Hepa filter. Further, instead of providing both the filter 9 and the fan 8, only one of them may be provided. Although the air suction port is not shown, a large number of holes may be formed as in the above embodiment, or the end of the pipe 80 may be simply opened.

In the above configuration, air is forced into the furnace, and the effect of suppressing the rise of dust and fume due to the downward flow of air within the furnace is the same as described above. Further, in this embodiment, it is easier to adjust the amount of air supplied than when using only the air intake port 35. Furthermore, by providing the filter 9, leakage of radioactive substances to the outside of the reactor can be more reliably prevented.

(Effects of the device) As explained above, this device arranges the head tuner in the upper part of the furnace body in a movable manner in a microwave melting furnace, and also forms a nearly uniform gap between the outer periphery of the head tuner and the inner surface of the furnace body. let me,
In addition, an air suction port is formed in the furnace body above the head tuner to prevent dust and fume from rising by creating a downward airflow over the entire surface of the furnace. It is possible to reliably prevent particles from entering the head tuner section and the waveguide.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view showing an embodiment of this invention, Fig. 2 is a plan view thereof, Fig. 3 is a side view showing another embodiment, Fig. 4 is a perspective view of the conventional structure, and Fig. 5 is a plan view thereof. FIG. 6 is a vertical sectional view showing another example of the conventional structure.
FIG. 1... Furnace body, 2... Crucible, 3... Head tuner, 4... Waveguide, 5... Exhaust pipe, 30...
Shaft, 31... Guide portion, 35... Air intake port, A
...Updraft, E...Downdraft.

Claims (1)

[Scope of utility model registration request] In a microwave melting furnace, a workpiece is supplied into a crucible, the workpiece is irradiated with microwaves, and the offgas is discharged by suctioning air from an intake port. The microwave melting device is characterized in that the head tuner is arranged to be movable up and down, a substantially uniform gap is formed between the outer periphery of the head tuner and the inner surface of the furnace body, and an air suction port is formed in the furnace body above the head tuner. Furnace.