JPH0686056B2 - Microwave dryer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a microwave dryer.

(B) Prior art Japanese Utility Model Laid-Open No. 59-91592 discloses a microwave drying device for microwave-drying a material to be dried by applying microwaves to the drying chamber. There is.

Then, after being microwave-dried, the material to be dried is supplied into the drying chamber from above.

Thus, in this case, the material to be dried supplied to the drying chamber cannot be supplied to the drying chamber from the upper portion unless it is above the drying chamber, that is, when the material to be dried is below the drying chamber. Cannot supply the material to be dried into the drying chamber.

(C) Problem to be Solved by the Invention The present invention can supply an object to be dried into the drying chamber even if the object to be dried supplied to the drying chamber is below the drying chamber, and In order to realize the above, it is intended to make the structure easy to clean and prevent microwave leakage.

(D) Means for Solving the Problems A microwave drying apparatus of the present invention includes a drying chamber, a microwave supplying unit that supplies microwaves for performing microwave drying to the drying chamber, and granular or granular materials to be dried. A storage part for storing the material, a material to be dried supply pipe connecting the storage part and the upper drying chamber, and a material to be dried in the upper storage part is sucked through the material to be dried supply pipe, and is introduced into the drying chamber. And a suction chamber provided between the drying chamber and the suction means, the suction means for supplying the suction means having a detachable filter for preventing the material to be dried from being sucked into the suction means. A microwave blocking pipe that connects the suction chamber and the drying chamber and shuts off the microwaves supplied to the drying chamber, and the suction chamber uses the weight by itself when sucking the object to be dried. On top of falling into a drying room It is arranged at a position above the drying chamber.

(E) Action Even if the storage part for storing the material to be dried is located below the drying chamber, the material to be dried is sucked by the driving of the suction means and supplied to the drying chamber.

Furthermore, since the suction chamber provided for such suction is connected to the drying chamber via the microwave blocking pipe,
The microwave is prevented from leaking to the suction chamber.

Furthermore, since the upper suction chamber is equipped with a filter,
Even if the material to be dried is sucked up to the suction chamber, the material to be dried is prevented from being sucked from there. Further, since the suctioned object to be dried is arranged in a position where the suction chamber falls into the drying chamber at the upper part of the drying chamber due to the weight of the object to be dried, when the operation of the suction means is stopped, the drying chamber is moved by its own weight. The material to be dried does not remain in the suction chamber.

Furthermore, since the upper filter is detachable, it can be easily cleaned when it becomes dirty, and the upper filter is located in the suction chamber where microwaves do not leak, so the filter can be made of wire mesh.

(H) Embodiment FIG. 1 shows the structure of a microwave drying apparatus according to an embodiment of the present invention, which comprises a drying apparatus main body (1) and its peripheral mechanism.

The drying apparatus main body (1) is provided with a cylindrical drying chamber (3) having an openable and closable upper lid (2) as a main part.
A supply pipe (4) is connected to the upper left portion of the drying chamber, and the tip of the supply pipe reaches a storage tank (6) for storing the granular or powdery material to be dried (5). The storage tank (6) is below the drying chamber (3). Examples of the material to be dried (5) include resin pellets, rice, and chemical powder particles. The resin pellets are molded after being melted, but if the resin pellets are dried prior to such melt molding, the subsequent molding will be performed well. In this embodiment, resin pellets are selected as the material to be dried (5). Further, a suction chamber, that is, a suction hopper (7) is connected to the center of the upper lid (2) of the drying chamber (3) through an integrally formed microphone mouth wave blocking pipe (7a).

As shown in FIG. 2, the suction hopper (7) is composed of a suction hopper body (7b) and a hopper upper lid (7c) detachably arranged on the body. The upper lid (7c) is engaged with the hook portions (7d) (7d) so that the upper lid (7c) does not come off undesirably when attached. A filter wire mesh (8a) and a filter paper (8) are detachably attached together with the packing (7e) so as to be sandwiched between the suction hopper body (7b) and the hopper upper lid (7c). The filter wire mesh (8a) and the filter paper (8) have a mesh smaller than the material diameter of the material to be dried (5), and the filter paper (8) has a smaller mesh than the filter wire mesh (8a).

Here, since the microwave blocking pipe (7a) is present in the hopper (7), microwaves supplied into the drying chamber (3) do not leak, as will be described later, and therefore safe. In addition, the filter wire mesh (8a) is used. If microwaves leak into the hopper (7), undesired discharge occurs in the filter wire netting (8a) due to the action of the leaking microwaves, so that the filter wire netting (8a) should be used. I can't. Furthermore, since the filter wire netting (8a) and the filter paper (8a) are detachable, they can be easily cleaned or replaced when they become dirty.

A poppet valve (9) is provided in the upper lid (7c) of the hopper (7), which is located above the filter wire mesh (8a) and the filter paper (8). Then, in the upper part of the poppet valve (9), a suction means, that is, a suction blower (11) is connected to the upper suction hopper (7) via an intake pipe (10).
Are connected. In this case, when the blower (11) is driven while the poppet valve (9) is driven to open, the intake action of the blower (11) causes the intake pipe (10), the suction hopper (7), and the microwave cutoff pipe. (7a) and the drying chamber (3) to the supply pipe (4), the material to be dried 5 in the storage tank (6) is sucked and passes through the supply pipe (4) to the drying chamber (3). Reach When the material to be dried (5) reaches the drying chamber (3), it falls by its own weight and accumulates therein.

Here, the material to be dried (5) may not fall into the drying chamber (3) and is then further sucked to reach the inside of the suction hopper (7). Cannot be blocked by the filter wire mesh (8a) and the filter paper (8), so that the object to be dried (5) is prevented from being undesirably sucked toward the suction blower (11). . When the suction blower (11) is stopped, the suction hopper (7) passes through the microwave blocking pipe (7a) above the drying chamber (3) when the object to be dried sucked into the suction hopper (7) is stopped. Since the objects to be dried are sucked into the suction hopper (7), they fall into the drying chamber (3) by their own weight.

In the drying chamber (3), microwaves are supplied from the magnetron (12) to the inside of the drying chamber (3) through the waveguide (13), and the bottom wall is driven by the motor (14) to be dried (5). ) Is provided for stirring the level sensor (16) and a temperature sensor (17) such as a thermistor on the side wall.
Are arranged. The level sensor (16) detects whether or not a desired amount of the material to be dried (5) has accumulated in the drying chamber (3), and the temperature sensor (17) detects the temperature of the material to be dried (5). To do. In addition, the intake valve (1
A compressor (19) is connected via 8), and an exhaust valve (20) is provided on the upper lid (2) of the drying chamber (3). Drive these compressors (19) and intake valve (18)
Also, the exhaust valve (20) is opened when the material to be dried (5) is dried by microwaves, etc., and the steam generated at the time of drying and the like is discharged from the exhaust valve (20) together with the air from the compressor (19).
Is discharged to the outside through.

Further, a discharge valve (21) is provided on the right bottom portion of the drying chamber (3), and the discharge valve is opened when discharging the dried object (5) to be dried. The material to be dried (5) discharged based on the opening of the discharge valve (21) falls through the discharge pipe (22) into the lower preliminary chamber (23) and accumulates therein. A temperature heater (24) is arranged on the lower inclined wall of the preliminary chamber, and a level sensor (26) having a rotating body (25) is provided in the preliminary chamber (23). Such a level sensor (26) normally rotates the rotating body (25), and
Even if an attempt is made to rotate the rotating body (25) by accumulating a small amount of the dried object (5) inside 3), the dried object (5) becomes a load and the rotating body (25) is satisfied. When it cannot rotate, it outputs a predetermined signal to detect that the material to be dried (5) has accumulated a slight predetermined amount.

The lower part of the spare chamber (23) is connected to another suction hopper (27) located higher than the spare chamber (23) through a transfer pipe (28). Like the suction hopper (7), the suction hopper (27) is also provided with a filter wire net (29) and a filter paper (29) having a mesh smaller than the material diameter of the material to be dried (5), and A poppet valve (30) is provided above the filter paper. Then, in the upper part of the poppet valve (30), the upper suction hopper (27)
Also, the suction blower (11) is connected via an intake pipe (31). In this case, if the blower (11) is driven with the poppet valve (30) opened, the blower (1)
The intake action of 1) is the intake pipe (31), suction hopper (27)
To the transfer pipe (28) through the auxiliary chamber (23)
The material to be dried (5) accumulated in the above reaches the suction hopper (27) through the transfer pipe (28). When the material to be dried (5) reaches the suction hopper (27), it falls into the popper due to its own weight. Further, in the suction hopper (27), the heat retaining heater (32) is arranged on the lower inclined wall, and the open / close valve (33) is provided at the lower end.
Is provided, and upper and lower limit level sensors (34) (35) are arranged at the upper and lower portions. Open / close valve (33)
In the closing of the suction hopper (2), when the object to be dried (5) falls into the intake hopper (27) due to the above-mentioned intake action.
The material to be dried (5) collects in 7), while the open / close valve (33)
When the opening is opened, the material to be dried (5) thus accumulated falls downward to reach the next-stage processing section, and the material to be dried (5), that is, resin pellets dried in such processing section is melt-molded. It

FIG. 3 shows the circuit of the microwave drying device, and a microcomputer (36) of product number LC-65PG23 manufactured by Sanyo Electric Co., Ltd. is provided as a main control unit, and the computer is the drying device main body (1). Information from the operation section (37) disposed on the front surface of the vehicle, temperature information from the temperature sensor 17, the various level sensors (16) (26) (34) (35)
Based on the information from the magnetron (12), the motor (14), the intake valve (18), the exhaust valve (20), the compressor (19), the exhaust valve (21), the heater (24) (32), Suction blower (11), poppet valve (9) (30), open / close valve (33)
Drive control.

FIG. 4 shows a flow chart of an operation program incorporated in the microcomputer (36), and the operation of the microwave dryer will be described below with reference to the chart.

After turning on the power, go through the S1 step and then use the normal S2, S3, S3a, S
4 and S5 are cyclically executed. In step S1, initial setting operation is performed. That is, all the writable areas in the microcomputer (36) are cleared, and the magnetron (12), motor (14), compressor (19), heaters (24) (32), suction blower ( 11) is placed in the drive stopped state and the intake valve (1
8), exhaust valve (20), discharge valve (21), poppet valve (9)
(30) and the on-off valve (33) are placed in the closed state. In S2 step, the operation information from the operation section (37) is input, and in S3 step, the lower limit level sensor (35) determines whether or not the material to be dried (5) is accumulated in the suction hopper (27). , In the S3a step, the level sensor (2
Based on the detection of 6), it is determined whether or not a small amount of the material to be dried (5) is accumulated in the preliminary chamber (23). In step S4, it is checked whether or not the start flag is set in the computer (36), and in step S5, it is determined whether or not the start key is currently operated by the operation section (37) based on the input information in step S2. It

Thus, when the material to be dried (5), which is a resin pellet, is melt-molded and the material to be dried (5) is dried in advance so that such molding can be performed well, first, the operation part (37) is hand,
Within the range of 20 to 60 minutes and the range of 70 to 170 ° C., the desired drying time and drying temperature are set by key operation, and the continuous switch (38) is turned on. These operation information are input in step S2. After that, when the start key is operated on the operation section (37), such information is similarly input in step S2, an affirmative judgment is made in step S5, the start flag is set in step S6, and then in step S7. Then, the drive control of each of the heat retention heaters (24) (32) is started. That is, each of the heat retaining heaters (24) (32) is intermittently driven at a desired ratio so that the insides of the preliminary chamber (23) and the suction hopper (27) are approximately maintained at the set drying temperature, and therefore the preliminary chamber is The inside of (23) and the suction hopper (27) is kept at the above temperature.

Then, steps S8, S9, and S10 are sequentially executed. S8
In step, it is checked whether or not the transport flag in the computer (36) is set (in this case, it is checked that it is not set). In step S9, the operation of supplying the material to be dried (5) to the drying chamber (3) is executed. That is, the poppet valve (9) is opened and the suction blower (11) is driven,
The material to be dried (5) is supplied from the storage tank (6) into the drying chamber (3) by the suction action of the blower (11), and the motor (14) is driven to rotate the agitator (15), The top surface of the material to be dried (5) supplied into the drying chamber (3) is aligned with a smooth horizontal surface. In step S10, whether or not the upper surface of the object to be dried (5) reaches the position of this sensor (16) by the detection of the level sensor (16) and the object to be dried (5) has accumulated in the drying chamber (3) by a predetermined amount. Is determined (in this case, it is determined that the predetermined amount is not accumulated).

Then, the steps S2, S3, S3a, S4, S11, and S8 to S10 are cyclically executed. At this time, in step S11, it is checked whether or not the supply end flag in the computer (36) is set. Then, a predetermined amount of the material to be dried (5) is accumulated in the drying chamber (3), and if this is determined in step S10, then S12, S1
3 steps are executed. In step S12, the operation of supplying the material to be dried (5) to the drying chamber (3) executed in step S9 is ended. In step S13, the supply end flag is set.

Then, steps S2, S3, S3a, S4, S11, and S14 to S17 are cyclically executed. At this time, in step S14, it is checked whether or not the drying end flag is set in the computer (36), and in step S15, the drying operation is executed. That is, the magnetron (12) is intermittently driven depending on whether or not the temperature of the article to be dried (5) detected by the temperature sensor (17) reaches the set drying temperature, and the article to be dried (5) is dried at the drying temperature. Maintained in the microwave and dried, and the motor (14)
Is re-driven to rotate the agitator (15) and to be dried (5)
Is agitated so as to be evenly dried, and the compressor (19) is driven and the intake valve (18) and the exhaust valve (20) are opened so that water vapor generated from the material to be dried (5) is discharged to the outside. Is discharged. Further, in the step S15, the time of the drying elapsed time is started together with such a drying operation. In step S16, it is determined whether or not the drying elapsed time has reached the set drying time, and in step S17, whether or not the transport flag is set is checked as in step S8.

When the elapsed dry time reaches the set dry time, S1
After 6 steps, S18 and S19 steps are executed. In step S18, the time for the drying operation and the elapsed drying time, which is executed in step S15, is ended, and the time counted is set. In step S19, the drying end flag is set.

Then, after steps S17, S2, S3, S3a, S4, S11, and S14, steps S20, S21, S22, S23, and S24 are sequentially executed. In step S20, it is checked whether or not the ejection flag in the computer (36) is set. In step S21, the spare room (2
In 3), it is judged whether or not the material to be dried (5) has already accumulated a slight predetermined amount. In step S22, when the heat retaining operation (described later) in the drying chamber (3) is being performed, this is finished and the discharge flag is set. In the S23 step, the dried object (5) is placed in the preliminary chamber (23) in the above S21 step.
Is allowed to be newly discharged from the drying chamber (3) to the preliminary chamber (23) because a predetermined amount is not accumulated, and the step S23 is performed. Then, the operation of discharging the dried material (5) from the drying chamber (3) to the preliminary chamber (23) is executed. That is, the discharge valve (21) is opened, the motor (14) is continuously driven to rotate the stirring body (15), and the stirring body (15) is rotated in accordance with the rotation of the stirring body (15). 15) The material to be dried (5) in the vicinity is pushed to the surroundings, and the material to be dried (5) falls from the discharge valve (21) through the discharge pipe (22) and is discharged to the preliminary chamber (23). Material to be dried discharged in this way (5)
Since the preliminary chamber (23) is kept warm from the step S7, it is prevented from being naturally cooled, and the substance to be dried (5) is prevented from absorbing moisture again due to the natural cooling. Further, in step S23, the time counting of the elapsed time of such discharge is started. In step S24, the discharge elapsed time is a predetermined discharge time (this is a time sufficient to discharge all the predetermined amount of material to be dried (5) stored in the drying chamber (3)). Is determined.

After that, S2, S3, S3a, S4, S11, S14, S20, S23, S24,
When each step of S17 is cyclically executed, and a small predetermined amount of the material to be dried (5) is accumulated in the preliminary chamber (23) due to the discharge, the steps S3a to S25, S26, S2 in this cycle are performed.
7, each step of S28 is sequentially executed. In step S25, the transport flag is set, and in step S26, the above S9
When the material to be dried supply operation is executed in step, such operation is stopped. In step S27, an operation of transporting the dried object (5) to the suction hopper (27) from the preliminary chamber (23) which is kept warm is executed. That is, the poppet valve (30) is opened, the suction blower (11) is driven, and the preliminary chamber (23) is driven by the intake action of the blower (11).
The material (5) to be dried is conveyed from the suction hopper (27).
Since the suction hopper (27) keeps the temperature of the material (5) to be dried conveyed in this way from the above step S7, the material to be dried (5) is prevented from absorbing moisture again. To be done. In step S28, it is determined whether or not the material to be dried (5) has accumulated in the suction hopper (27) up to the position of the sensor by the detection of the upper limit level sensor (34) (in this case, it is determined to be no). ). Then S4,
Each step of S11, S14, S20, S23, S24, S17, S27, S28 is cyclically executed, during which the discharge operation to the preliminary chamber (23) and the transfer operation to the suction hopper (27) are performed in parallel, The material to be dried (5) discharged to the preliminary chamber (23) is immediately conveyed to the suction hopper (27).

Then, when the discharge elapsed time reaches a predetermined discharge time (all the material to be dried (5) is discharged from the drying chamber (3) to the preliminary chamber (23)), then S29, S30, and S31 Each step is sequentially executed. In step S29, the discharge operation and discharge elapsed time, which have been executed in step S23, have been timed, and the time measured has been reset. S30
In the step, all of the above-mentioned supply end flag, drying end flag, and discharge flag are reset. In step S31, it is determined whether the operation unit (37) has the continuous switch (38) turned on.

In the present case, the continuous switch (38) is in the ON state, and thereafter, after passing through the S17 switch, the steps S4, S11, S8, S27 and S28 are cyclically executed. Then, when the material to be dried (5) in the preliminary chamber (23) is transported and the material to be dried (5) is accumulated in the suction hopper (27) to the position of the upper limit level sensor (34), the steps S28 to S32 are performed. , S33 step is executed. S
In step 32, the carrying operation executed in step S27 is stopped, and in step S33, the carrying flag is reset.

Thus, the material to be dried (5) thus accumulated in the suction hopper (27) is melted and formed in the next-stage processing section. This is executed when an external command signal P for commanding melt molding is applied to the computer (26) in a state where the material to be dried (5) is accumulated up to the position of 34). That is, at this time, the opening / closing valve (36) is opened by the computer (36), and the material to be dried (5) is discharged from the suction hopper (27) to the next stage processing section. The on-off valve (33) is closed again when all the material to be dried (5) in the suction hopper (27) has been discharged. The released material (5) to be dried is melt-molded in the next-stage treatment section. In this case, the resin pellets, that is, the material (5) to be dried is dried in advance, so that the molding is performed well. .

Here, when the processing capacity of the next-stage processing unit for the melt-molding is slow, the suction hopper (27) and the auxiliary chamber (23) are repeated because the operation of supplying the material to be dried and the operation of conveying the material are repeatedly performed. The material to be dried (5) remains in the area. Then, in a state where the material to be dried (5) is accumulated in the preliminary chamber (23),
Further, when the material to be dried (5) is to be discharged from the drying chamber (3), this is judged in step S21, that is, the material to be dried (5) is accumulated in the preliminary chamber (23) by a predetermined amount or more and dried. It is judged that it is not permissible to newly discharge the material to be dried (5) from the chamber (3) to the spare chamber (23). Then, the dried object (5) is left in the drying chamber (3) as it is after being dried. If such leaving is simply performed, the material to be dried (5) is naturally cooled and absorbs moisture again even if it is dried, but in the embodiment of the present invention, in order to prevent this, at this time S3
4 steps are executed. That is, in such S34 step,
Exactly the same control as the drying operation in step S15 is performed, and the material to be dried (5) is kept at the set drying temperature by microwave,
Therefore, the material to be dried (5) is prevented from absorbing moisture again in the drying chamber (3).

The above series of operations is ended by turning off the continuous switch (38). That is, when the step S31 is executed at the time of turning off, the step S35 is then executed, the start flag is set, and the heaters (24) (32) are stopped. Then S2, S3, S3a, S
4, S5 step is cyclically executed.

However, since the transport flag is set if the product to be dried is being transported, it is determined that the transport flag is set in step S17, and the transport operation in step S27 is performed, and in step S28, the suction hopper (27) is loaded into the product to be dried. Is continuously executed until it is determined whether or not has accumulated up to the position of the upper limit level sensor (34).

(G) Effect of the Invention According to the present invention, even if the storage tank for storing the material to be dried is located below the drying chamber, the material to be dried can be sucked by driving the suction means and can be supplied into the drying chamber.

Furthermore, since the suction chamber provided for such suction is connected to the drying chamber via the microwave blocking pipe,
It is safe because it can prevent the microwave from leaking to the suction chamber.

Further, since the suction chamber is provided with the filter, even if the material to be dried is sucked up to the suction chamber, it is possible to prevent the material to be dried from being sucked undesirably from there.

Further, since the suction chamber is disposed above the drying chamber, the substance to be dried sucked into the suction chamber falls into the drying chamber by its own weight when the operation of the suction means is stopped. Therefore, the material to be dried remains in the suction chamber, and it is possible to prevent the suction force from being reduced by narrowing the suction path of the suction means.

Further, since the filter is detachable, it can be easily cleaned when it becomes dirty, and the filter can be formed of a wire mesh because it is located in the suction chamber and where microwaves do not leak.

As described above, according to the present invention, it is possible to obtain an extremely practical microwave drying device that exhibits various effects.

[Brief description of drawings]

1 is a sectional view, FIG. 2 is an exploded perspective view of essential parts, FIG. 3 is a circuit diagram, and FIG. 4 is a flowchart of an operation program of a microcomputer. (3) …… drying room, (4) …… supply pipe, (6) ……
Storage tank, (7) ... Suction hopper, (7a) ... Microwave blocking pipe, (8a) ... Filter wire mesh, (8) ... Filter paper, (11) ... Suction blower, (12) ... Magntron .

Claims (1)

[Claims] 1. A drying chamber, and a microwave supply means for supplying a microwave for performing microwave drying to the drying chamber,
A storage part for storing the granular or powdery material to be dried, a dried material supply pipe connecting the storage part and the drying chamber, and a material to be dried in the storage part is sucked through the dried material supply pipe. And a suction means for supplying into the drying chamber, having a detachable filter for preventing the object to be dried from sucking into the suction means, and between the drying chamber and the suction means. And a microwave blocking pipe that connects the suction chamber and the drying chamber and blocks the microwave supplied to the drying chamber, and the suction chamber sucks the material to be dried. The microwave drying apparatus is arranged at a position above the drying chamber where it falls into the drying chamber under its own weight.