JPH0123712B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a continuous processing apparatus that performs microwave processing to heat, concentrate, dehydrate, dry, sterilize, burn, etc. a material to be processed.

In recent years, microwaves are often used to perform processes such as heating, concentration, dehydration, drying, sterilization, combustion, and reactions in the waste treatment field, chemical industry, drug manufacturing industry, food industry, etc. I'm getting used to it.

A coaxial microwave drying device such as the microwave drying device described in JP-A-55-99573 is an example of a drying device that uses microwaves to dry water-containing substances such as powder, particles, and sludge. It has been known.

Conventional common coaxial microwave drying equipment is
As shown in FIG. 9, a cylindrical body 1 made of a microwave reflective material such as metal, and a microwave transparent material (generally called a dielectric material) such as Teflon, glass, ceramics, polypropylene, polyethylene, quartz, alumina, etc. It consists of a rotating shaft 3 equipped with screw blades 2 formed by a microwave inlet 4, which guides microwaves into the cylindrical body 1 through a microwave inlet 4, dielectrically heats the water-containing material injected through an inlet 5, and transfers it to an outlet. 6 is discharged as a dry product.

However, in the so-called coaxial microwave heat treatment equipment where microwaves are applied in the same direction as the axial direction of the rotating shaft, the strength of the microwave power or the heating temperature can be adjusted depending on the position in the movement path of the water-containing material. Difficult to optimally control
There was a problem with poor heating efficiency.

The present invention was made in view of the above problems, and
It is an object of the present invention to provide a continuous processing device for drying, etc., which can uniformly spread microwaves and perform microwave processing efficiently.

In order to achieve the above object, the present invention provides a vertical cylindrical body made of a microwave transparent material in a microwave irradiation chamber, and includes a rotating shaft rotated by a drive device inside the vertical cylindrical body. The axis is aligned with the axis of the vertical cylindrical body, and the inner edge of the screw blade for transferring the workpiece is fixed to the outer surface of the rotating shaft, and the outer edge of the screw blade is close to the inner circumferential surface of the vertical cylindrical body. or contact with each other, and further tilt the upper surface of the screw blade so that the outer edge side is lower than the inner edge side, and place the screw blade at a position substantially corresponding to the substantial microwave irradiation area of the microwave irradiation chamber into the microwave irradiation chamber. It is made of a wave-transmitting material, and is transported by screw blades inside a vertical cylinder, and the microwaves are distributed vertically to the workpiece, which has a very large free surface area, through the side wall of the vertical cylinder. The entire surface is irradiated, and the layer thickness of the object placed on the top surface of the inclined screw blade is made thinner as it approaches the rotation axis, where microwaves are relatively weak, and The efficiency of microwave processing is improved by creating agitation near the inner surface of the vertical cylinder due to the frictional force between the object to be processed and the inner surface of the cylinder.

Hereinafter, one embodiment of the present invention will be described based on FIG.

In FIG. 1, the reference numeral 10 indicates a microwave open (microwave irradiation chamber). This microwave opener 10 has, for example, a cylindrical body plate 11 made of metal, which is a microwave reflecting material.
An upper lid 12 and a lower lid 13 made of metal are provided at the upper and lower parts of the housing to close the openings in the upper and lower parts, respectively, and the upper lid 12 and the lower lid 13 have screw portions formed at their ends. By inserting the upper and lower ends of the plurality of connecting rods 14 into the through-holes of the upper end 12 and the lower cover 13 and screwing nuts from the ends, the connecting rods 14 are connected and fixed to each other and fixed at a predetermined position on the body plate 11. One end of a metal waveguide 15 is connected to the waveguide 15, and a microwave oscillation device (microwave generation means) 16 is provided at the other end of the waveguide 15.

Furthermore, inside the microwave open 10,
A vertical shape having a smaller diameter than the body plate 11 and made of a microwave transparent material such as ceramic, glass, or Teflon (generally called a dielectric material, which has a relatively small dielectric loss coefficient and transmits microwaves). A cylindrical body 17 is disposed with its axis aligned with the axis of the open 10, and this vertical cylindrical body 1
7 is also closed at its top and bottom by the upper lid 12 and lower lid 13, respectively. In addition, this vertical cylindrical body 1
A gas supply pipe 18 for supplying an inert gas into the inside of the vertical cylinder 17 is connected to a lower position of the side wall of the cylinder 7, while a gas supply pipe 18 for supplying inert gas into the inside of the vertical cylinder 17 is connected to the upper lid 12. A workpiece supply pipe 19 for supplying objects into the vertical cylinder 17 and a gas exhaust pipe 20 for discharging the gas inside the vertical cylinder 17 are provided, and the lower lid 13 is provided with: Vertical cylindrical body 1
Processed material discharge pipe 2 for discharging the processed material in 7 to the outside of the device
1 is connected. The to-be-processed material supply pipe 19 has a hopper 2 at one end that receives the to-be-processed material.
2 is connected to the other end of the screw feeder 23, and the gas discharge pipe 20 is connected to the condenser 24. In addition, the above-mentioned processing material supply pipe 19, processing material discharge pipe 21, gas supply pipe 18,
Each of the gas exhaust pipes 20 is formed in a size that is cut off against microwaves.

On the other hand, at the center of the vertical cylindrical body 17, a rotating shaft 25 made of metal or a microwave-transmitting material is arranged with its axis aligned with the axis of the vertical cylindrical body 17. The rotating shaft 25 passes through the upper lid 12 and the lower lid 13 and is rotatably supported by the upper lid 12 and the lower lid 13 by bearings (not shown), and has a drive device such as a drive motor at its upper end. 26 are connected. In addition, this rotating shaft 25
A screw blade 27 made of a microwave transparent material such as ceramic is attached to the screw blade 27 . The screw blade 27 has an inner edge 27a fixed to the outer circumferential surface of the rotating shaft 25, an outer edge 27b located close to the inner circumferential surface of the vertical cylindrical body 17, and has a spiral shape. is inclined so that the outer edge 27b side is lower than the inner edge 27a side.

In the figure, 28 is a metal distribution plate that evenly distributes the microwaves sent from the waveguide 15 within the vertical cylindrical body 17, and 40 is a metal distribution plate that distributes the processed material through the processed material discharge pipe 21. It is a scraper that leads to 29
is the discharge valve.

Therefore, in the continuous processing apparatus described above, when drying a material to be processed such as a water-containing material containing harmful substances, first, the drive device 26 is activated to rotate the rotating shaft 25 and the screw blades 27 to be rotated. Next, an inert gas is supplied from the gas supply pipe 18 into the vertical cylinder 17, and the microwave oscillator 16 is activated to oscillate microwaves, and the microwaves are transmitted from the waveguide 15 to the microwave opener 10.
Lead inward. Then, the screw feeder 23 is operated to continuously feed the processed material stored in the hopper 22 into the vertical cylindrical body 17 from the processed material supply pipe 19, and the discharge valve 29 is opened at a predetermined position. Open at the timing of . Then, the object to be processed falls onto the spiral surface of the upper surface of the screw blade 27, and due to its inclination and gravity, is moved to the inner peripheral surface of the vertical cylindrical body 17, and is rotated while contacting the inner peripheral surface. and is gradually transported downward. microwave open 10
The microwaves entering the interior are directly absorbed by the object through the side wall of the vertical cylindrical body 17 made of a microwave-transmitting material. The processed material is gradually dried and heated, and the processed material has a predetermined moisture content, and is continuously discharged from the processed material discharge pipe 21. Further, the water vapor generated by drying and heating the object to be treated is guided along with the accompanying gas from the gas exhaust pipe 20 to the condenser 24, cooled, and condensed and separated.

Here, in the above-mentioned continuous processing apparatus, the processed material that has fallen onto the screw blade 27 is transferred downward without being relatively stirred, so that the dried processed material is not scattered as dust. Less is. Further, the microwave enters the inside of the vertical cylindrical body 17 made of a microwave-transmitting material by passing through the side wall from almost the entire surface of the side wall, and also passes through the screw blade 27 made of a microwave-transmitting material. Therefore, the object being transported on the upper surface of the screw blade 27 can receive microwaves from its entire circumference. Furthermore, since the screw blade 27 is vertical, the free surface area of the object to be processed is much larger than in the case of a conventional horizontal screw blade. Furthermore, microwaves gradually attenuate when absorbed by the object to be processed, and there is a limit to the depth of penetration; however, the layer thickness of the object to be processed on the upper surface of the screw blade 27 is relatively small. The layer is thinner near the rotating shaft 25, where the microwave is weaker, and the microwave penetrates into the center of the layer. Therefore, the drying and heating efficiency of the processed material is extremely high.
It also becomes easier to control the heating temperature.

In addition, in the above continuous processing apparatus, the screw blade 2
By changing the rotational speed of 7, the residence time of the object to be treated within the vertical cylindrical body 17 can be freely adjusted. Furthermore, the spiral surface of the upper surface of the screw blade 27 is inclined so that the outer edge 27b is lower than the inner edge 27a, so that even the objects to be processed that would not fall unless the screw blade is tilted are large enough to fall. It can be dropped in small pitches, and the device can be made smaller. It is also easy to maintain the airtightness of the device. Incidentally, in the above description, the screw blades 27 are uniformly pitched and single. However, the physical properties of the object to be treated vary depending on what is being handled, and also change as the moisture content decreases during the process of drying and heating. Therefore, to accommodate this, screw blades 27 of various shapes are used.

Figure 2 shows the lower pitch of the screw wing 27.
P ₁ is made smaller than the pitch P ₂ on the upper side. This is because the material to be treated has a high water content and has poor flow on the upper side of the screw blade 27, but on the lower side of the screw blade 27, the water content decreases and the flow speed becomes faster, which may generate dust. This is to prevent this from happening. The radial inclination θ of the screw blade 27 is preferably 5° to 40° with respect to the horizontal. For the same purpose, the third
As shown in the figure, the upper part 2 of the screw wing 27
7c may have an inclined shape, and the lower portion 27d may have a horizontal shape.

FIG. 4 shows a plurality of screw blades 27 attached to a rotating shaft 25 with spacers 30 interposed therebetween. In this case, depending on the physical properties of the material to be treated and changes in its physical properties during the drying and heating process, the material to be treated can be combined with horizontal screw blades as described above, or by selecting the pitch, length, etc. as appropriate. 27, the dust is transferred downward without being stirred relatively, but in the discontinuous portion where the spacer 30 is interposed, the dust falls and is stirred to such an extent that no scattering of dust occurs, thereby increasing the drying efficiency. In FIG. 5, a plurality of pieces 31 are provided on the outer edge 27b of the screw wing 27. Each piece 31
has a plurality of long holes 31a extending in the radial direction of the screw blade 27, and a plurality of bolts 32a screwed through the outer edge 27b of the screw blade 27 through the outer edge 27b are passed through the long holes 31a. , by screwing a nut 32b thereto, it is locked to the screw blade 27, and the screw blade 27 can freely move in the radial direction. Therefore, the piece 31 comes into contact with the inner circumferential surface of the vertical cylindrical body 17 and rotates due to its own weight. Therefore, the object to be processed is the screw blade 27 and the vertical cylindrical body 1.
This prevents the workpiece from falling between the inner peripheral surface of the vertical cylinder 17 and the workpiece passing through the vertical cylindrical body 17. Furthermore, by attaching this piece 31, the outer diameter of the entire screw wing 27 automatically becomes approximately equal to the inner diameter of the vertical cylindrical body 17, so there is no need to precisely process the outer periphery of the screw wing 27. , its production is extremely easy. Note that the gap between the inner peripheral surface of the vertical cylindrical body 17 and the screw blade 27 may be adjusted by fixing the piece 31 at an appropriate position with the bolt 32a and nut 32b.

On the other hand, in the embodiment shown in FIG. 1, a distribution plate 28 is provided in the microwave opener 10 to ensure uniform propagation of microwaves. Wings may be provided. Furthermore, local heating of the object to be treated is likely to occur at the upper stage of the screw blade 27 where the moisture content of the object to be treated is high. This localized heating may be prevented by reducing it with a metal shield disposed at an appropriate distance from the outer surface of the sidewall.

Furthermore, as shown in FIG. In the cylindrical body 17,
A rotary shaft 25 including screw blades 27 and rotated by a drive device 26 may be provided to increase the processing efficiency of the object to be processed. A pressure reducing device 34 such as a blower or a vacuum pump
The vertical cylindrical body 1 is placed inside the microwave open 10 by
It is also possible to create a negative pressure from inside 7 so that water vapor, decomposition gas, etc. generated by dry heating can be taken out from the side wall of the vertical cylindrical body 17.

In addition, FIG. 7 shows multiple microwave open 1
0 are stacked one on top of the other, and the above-mentioned vertical cylindrical body 17 is arranged therein, and the boundary between each microwave open 10 is formed of metal, and this part is used as a microwave reflecting wall 10a. A microwave shielding portion is formed by providing a microwave reflecting material 35 on the lower surface of the portion 27e of the screw blade 27 located at a position corresponding to the microwave reflecting wall 10a, and each microwave opening 10 is provided with a microwave shielding portion. A microwave oscillation device 16 is provided, and each microwave oscillation device 16 is provided with a temperature controller 36. Each microwave oscillation device 1 is controlled by each temperature controller 36.
By controlling the input power of each microwave generated at 6, the heating temperature at each microwave open 10 can be optimally controlled. Therefore, the physical properties of the object to be treated change as the moisture content decreases during the drying and heating process.
According to this change, the heating temperature in each microwave opener 10 can be optimally adjusted, and power loss can be minimized. Further, the rotating shaft 25 of the portion 27e of the screw blade 27 located at the position corresponding to the microwave reflecting wall 10a is preferably made of metal, but if the shaft diameter is large enough to cut off against microwaves, it is particularly preferable to use metal. There is no need to make it. Furthermore, a metal member 35 may be provided on the upper surface of the portion 27e of the screw blade 27 at a position corresponding to the microwave reflecting wall 10a. It is preferable that the pitch of this part is cut-off for microwaves, but it is not necessary to do so because there is no problem even if some microwaves leak.

In FIG. 8, the rotating shaft 25 is made of metal, and a short screw blade 27f made of metal is provided over almost the entire length of the rotating shaft 25 at a position corresponding to the microwave reflecting wall 10a. A microwave shielding portion is formed separately from the screw blade 27g. Here, 37 in the figure is a stopper member.

Furthermore, the above device can be used as a combustion device for carbonization, incineration, catalyst regeneration, etc. by forming them from heat-resistant steel or the like and appropriately selecting the gas body to be supplied to the gas supply pipe 18. It can also be used as a moving bed catalytic reaction device by using a catalyst instead of the object to be treated and allowing the fluid to be reacted to flow through the vertical cylindrical body 17. In this case, it goes without saying that it is necessary to select an appropriate microwave transmitting material depending on the processing temperature.

As explained above, in the continuous processing apparatus for drying, etc. of the present invention, microwaves are transmitted through the side wall from substantially the entire surface of the side wall into the interior of the vertical cylinder formed of the microwave-transmitting material. The object to be treated can receive microwaves from its entire circumference, and the object to be treated is dispersed vertically by the screw blades, increasing the free surface area.
The layer thickness of the object to be treated is made thinner as it approaches the rotation axis, where microwaves are relatively weak, and furthermore, near the inner surface of the vertical cylinder, where microwaves are relatively strong, the layer thickness is reduced due to the frictional force between the object to be processed and the inner surface of the cylinder. Since the microwave treatment generates stirring, the efficiency of microwave treatment of the object to be treated is extremely high.

Furthermore, by adjusting the rotational speed, pitch, and inclination angle of the screw blades, it is easy to control the heating temperature, etc., and it is also easy to adjust the residence time of the device, downsize it, maintain airtightness, etc.

In addition, since the object to be treated is heated using microwaves while being moved by screw blades,
Even when an object to be treated, such as a water-containing substance containing harmful substances, is dried to a high degree of dryness, the object to be treated is unlikely to scatter as dust.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG.
Figures 5 to 5 show other configurations of the screw blade. Figure 2 is a sectional view when the lower pitch is smaller than the upper part, and Figure 3 is a combination of an inclined blade and a horizontal blade. 4 is a sectional view when a plurality of screw blades are combined via a spacer, FIG. 5 a is a sectional view when a piece is provided on the outer edge of the screw blade, and FIG. FIG. 6 to 8 are sectional views showing other embodiments, and FIG. 9 is a sectional view showing a conventional device. 10... Microwave open (microwave irradiation chamber), 16... Microwave oscillation device (microwave generation means), 17... Vertical cylindrical body, 25... Rotating shaft, 26... Drive device, 27... screw wing,
30... Spacer, 31... Piece, 34... Pressure reducing device.

Claims (1)

[Scope of Claims] 1. A rotating shaft rotated by a drive device is provided in a microwave irradiation chamber having a microwave generating means and is formed of a microwave-transmitting material. The inner edge of a screw blade is provided to match the axis of the body, and the inner edge of the screw blade for transporting the object to be processed is fixed to the outer surface of the rotating shaft, and the outer edge of the screw blade is close to or in contact with the inner peripheral surface of the vertical cylindrical body. furthermore, the upper surface of the screw blade is inclined so that the outer edge side is lower than the inner edge side,
Further, a continuous processing device for drying, etc., characterized in that the screw blade at a position substantially corresponding to the substantial microwave irradiation area of the microwave irradiation chamber is formed of a microwave transparent material. 2. A vertical cylindrical body is disposed in a plurality of microwave irradiation chambers arranged in series, and a microwave reflecting material is provided in the vertical cylindrical body at a position corresponding to the microwave reflecting wall of the microwave irradiation chamber. 2. The continuous processing apparatus for drying and the like according to claim 1, further comprising a screw blade using a screw blade to form a microwave shielding part.