JPH03213A - Microwave drying device - Google Patents

Abstract

PURPOSE:To prevent the generation of defective product and the trouble of a device from occurring by a method wherein the generation of abnormality in a stirring means is detected with a detecting means and the drying action is stopped so as to suppress the ununiform drying of matter to be dried. CONSTITUTION:Microwave is supplied from a magnetron 15 through a waveguide 16 in the interior of a drying chamber 3, at the lower part of which a metal stirring body 20 rotatingly driven by a motor 19 through a rotating shaft connected to the motor 19 is provided. The stirring body 20 stirs not only matter to be dried 5 but also microwave, since it is made of metal. A piece of magnet 21 is fixed to a part of the under surface of the stirring body 20 and a reed switch 22 is provided at one position beneath the bottom wall 3a of the drying chamber. When the stirring body 20 is rotated under normal state, the reed switch 22 is turned ON by magnetic force when the piece of magnet 21 is rotatingly brought in the neighborhood of the position just above the reed switch. If abnormality generates in the stirring body 20, the reed switch 22 can not be turned ON in the same manner as turned at the normal rotation of the stirring body 20, resulting in detecting abnormality.

Description

[Detailed description of the invention] (b) Industrial application field The present invention relates to a microwave drying device.

(b) Prior art Japanese Patent Application No. 1-47804 discloses a microwave drying device that applies microwaves to a drying chamber into which the material to be dried is supplied to microwave-dry the material to be dried. . The apparatus is provided with a stirring means for stirring the material to be dried in the drying chamber so that the material to be dried is dried evenly. The stirring means is made of metal and also stirs with microwaves so that the material to be dried is dried evenly.

Here, regarding the stirring means, the following abnormalities may occur.

(After removing the stirring means to clean the inside of the drying room,
It is recommended to install stirring means.

(i) The stirring means comes off from the specified location during drying.

If an abnormality occurs in the stirring means in this way, the drying operation of the drying object will be performed without stirring the drying object and the microwave, and the drying object will be unevenly dried and may be partially dried. It will melt.

If the drying operation continues without noticing such melting, a large amount of defective products will be produced, and if the material to be dried solidifies after melting, the discharge part of the material to be dried will become clogged and the device may malfunction. Put it away.

(c) Problems to be Solved by the Invention The present invention prevents the production of defective products even if an abnormality occurs in the stirring means, and prevents the microwave drying device from malfunctioning. It is.

(d) Means for Solving the Problems The microwave drying apparatus of the present invention includes a drying chamber into which a granular or powdery material to be dried is supplied, and a microwave for microwave drying the material to be dried in the drying chamber. The apparatus includes a microwave supply means for supplying waves, a stirring means for stirring the material to be dried in the drying chamber and stirring the microwave, and a detection means for detecting an abnormality in the stirring means.

(e) Operation When an abnormality occurs in the stirring means, this is detected by the detection means, and the occurrence of the above-mentioned abnormality can be recognized. Therefore, the drying operation can be immediately stopped, the drying object can be prevented from being dried unevenly, and the occurrence of defective products and failure of the microwave drying apparatus can be prevented.

(f) Embodiment FIGS. 1 to 3 show the structure of a microwave drying apparatus according to an embodiment of the present invention, and the apparatus consists of a main body (1) of the drying apparatus and peripheral mechanisms thereof.

The main part of the drying apparatus (1) is provided with a cylindrical drying chamber (3) having an upper lid (2) that can be opened and closed.

A supply pipe (4) is connected to the upper left part of the drying chamber, and the tip of the supply pipe is connected to the granular or powdery material to be dried (5).
) into the storage tank (6) that stores the water. Such materials to be dried (5) include, for example, resin pellets, rice, powdered pharmaceutical products, and the like. The resin pellets are molded after being melted, or if the resin pellets are dried prior to such melt molding, the subsequent molding can be performed better. In this embodiment, a resin pellet is selected as the material to be dried (5).

Further, a suction hopper (7) is connected to the center of the upper lid (2) of the drying chamber (3). A filter wire mesh (8) having a mesh smaller than the material diameter of the dried material (5) is disposed within the hopper, and a poppet valve (9) is provided above the filter wire mesh. Such a poppet valve (9) is connected to a solenoid valve (10) and a compressed air pipe (11+
It is connected to the near compressor (12) via
Compressed air is supplied to the poppet valve (9) based on the opening of the solenoid valve (lO) and driving of the near compressor (12), and the poppet valve (9) is driven to open. At the upper part of the poppet valve (9), the suction hopper (7) is connected to a suction blower (
14) are connected. In this case, the poppet valve (9)
When the blower (14) is driven with the blower (14) being driven to open, the intake action of the blower (14) is caused by the
), the supply pipe (4) via the suction hopper (7) and the drying chamber (3), and the material to be dried (5) in the storage tank (6).
) passes through the supply pipe (4) to the drying chamber (3). When the material to be dried (5) reaches the drying chamber (3), it falls and accumulates therein due to its own weight.

Microwaves are supplied into the drying chamber (3) from a magnetron (15) via a waveguide (16). The magnetron (15) is connected to the duct (17)
The compressed air pipe +111 is connected to the near compressor (12), and the compressed air is connected to the compressed air pipe (111) based on the drive of the compressor (12).
11) through the duct 7) to the magnetron (15)
The magnetron (I5) is cooled.

Furthermore, a metal agitator (20) connected to a motor (19) via a rotating shaft (18) and rotationally driven by the motor (19) is provided at the lower part of the drying chamber (3). .

The stirring body (20) is detachable from the rotating shaft (18), and stirs the material to be dried (5), and since it is made of metal, it also stirs the microwave.

A magnet piece (21) is fixed to a part of the lower surface of the stirring body (20), and the locus of rotation of the magnet piece (21) accompanying the rotation of the stirring body (20) (Fig. 3 - dotted chain line) A reed switch (2) is installed at one place under the bottom wall (3a) of the drying chamber
2) is provided. The reed switch (22) is turned on by magnetic force when the stirring body (20) rotates in a normal state and the magnet piece (21) rotates near directly above it, and this on state is maintained for 0.2 seconds. .

The rotational speed of the stirring body (20) is determined so that it rotates 60 times per minute, and therefore the reed switch (22) is turned on once per second, and each time the reed switch (22) is turned on. It is held for 0.2 seconds.

If an abnormality occurs in the stirring body (20), for example, if you forget to attach the stirring body (20) after removing it to clean the inside of the drying room (3). , the magnetic force of the magnet piece (21) no longer acts on the reed switch (22), and the reed switch (22) is no longer turned on.

Also, the stirring body (20) may rotate 9 for some reason during stirring.
1 (18), the reed switch (22) will not turn on in the same way.

Also, if the stirring body (20) stops rotating for some reason during stirring and the magnet piece (21) stops at a position away from directly above the reed switch (22), the reed switch (22) will It will no longer turn on.

In addition, the stirring body (20) may be rotated for some reason during stirring.
If the rotation stops and the magnet piece (21) comes to a stop close to the reed switch (22), the magnetic force of the magnet piece (21) acts on the reed switch (22) and the reed switch (22) continues. 2
2) remains on.

In this way, when an abnormality occurs in the stirring body (20), the reed switch (22) can no longer be turned on every second as when the stirring body (20) is normally rotating, that is, the lead The switch (22) detects an abnormality in the stirring body (20). Here, such a reed switch (22)
corresponds to the detection means of the present invention.

Furthermore, a level sensor (2) is installed on the side wall of the drying chamber (3).
3) and a temperature sensor (24) such as a thermistor. The level sensor (23) detects whether a predetermined amount of the material to be dried (5) has accumulated in the drying chamber (3), and the temperature sensor (24) detects the temperature of the material to be dried (5). do.

Furthermore, an exhaust valve (25) is provided on the upper lid (2) of the drying chamber (3). This opening of the exhaust valve (25) is performed when the material to be dried (5) is dried using microwaves, and water vapor generated during drying is discharged to the outside through the exhaust valve (25).

Furthermore, a discharge valve (26) is provided at the bottom right of the drying chamber (3). Such a discharge valve (26) is a solenoid valve (27)
and the near compressor (through the compressed air pipe (eye)
12), and the discharge valve (12) is connected to the discharge valve (
Compressed air is supplied to the discharge valve (26), and the discharge valve (26) is driven to open. The discharge valve (26) is opened when the dried material (5) is discharged.

When the discharge valve (26) is opened, the dried material (5) is discharged through the discharge pipe (28) to the preliminary chamber (
29) and accumulates. A heat retainer (30) is arranged on the lower inclined wall of the preliminary chamber, and the preliminary chamber (2)
9) is a level sensor having a rotating body (31) <32)
is provided. Such a level sensor (32) normally rotates the rotary body (31), and when a predetermined amount of the material to be dried (5) accumulates in the preliminary chamber (29) and attempts to rotate the rotary body (31). However, when the object to be dried (5) is a load and the rotating body (31) cannot be rotated satisfactorily, a predetermined signal is output, and a predetermined amount of the object to be dried (5) is accumulated. detect that there is a

The lower part of the preliminary chamber (29) is connected to a conveying pipe (34) to another suction hopper (33) located higher than the preliminary chamber (29).
) are connected through. Similar to the suction hopper (7), the suction hopper (33) also includes a filter wire mesh (35) having a mesh smaller than the material diameter of the material to be dried (5).
is arranged, and a poppet valve (36) is provided above the filter wire mesh. Such a poppet valve (3
6) is connected to the near compressor (12) via a solenoid valve (37) and a compressed air pipe (11), and the above-mentioned poppet valve (36) is supplied with compressed air, and the poppet valve (36) is driven to open. At the upper part of the poppet valve (36), the suction blower (14) is also connected to the suction hopper (33) via an intake pipe (38). In this case, if the blower (14) is driven with the poppet valve (36) open, the intake action of the blower (14) will be transferred to the intake pipe (3).
8), conveying pipe (34) via suction hopper (33)
The material to be dried (5) accumulated in the preliminary chamber (29)
passes through the conveyance pipe (34) to the suction hopper (33).
leading to. When the material to be dried (5) reaches the suction hopper (33), it falls into the hopper due to its own weight.

In the suction hopper (33), a heat retainer (39) is arranged on the lower inclined wall, an on-off valve (4o) is provided at the lower end, and upper and lower limit level sensors (
41) (42) is placed. The above on-off valve (40
), when the suction action moves and the dried material (5+) falls into the suction hopper (33), the dried material (5) accumulates in the suction hopper (33), while the on-off valve (40 ) is opened, the dried material accumulated like this (5)
falls downward and reaches the next processing section, where the dried material (5), ie, the resin pellet, is melt-molded and molded.

Figure 4 shows the circuit of the microwave drying device, and the main control section is a part number LC-65PG23 manufactured by Sanyo Electric Co., Ltd.
A microcomputer (43) is provided, and the computer receives operation information from the operation section (44) disposed on the front side of the drying device main body (1) and temperature information from the temperature sensor (24). , the various level sensors mentioned above (23
) (32) (41) Based on the information from (42), the information from the reed switch (22), etc., the magnetron (15), motor (19), exhaust valve (25)
), compressor (12), heat retainer (30) (39
), suction blower (14), solenoid valve (10) (27)
! 37), an on-off valve (40), an abnormality buzzer (45), and an abnormality light emitting diode (46) disposed on the front surface of the drying apparatus main body).

FIG. 5 shows a flowchart of the main operation program incorporated in the microcomputer (43), and the operation of the microwave drying apparatus will be explained below along the same chart.

After turning on the power, it goes through the S1 step and then normally goes to S2, S3, and S3.
Steps 3a, S4, and S5 are executed cyclically. S1
In this step, an initial setting operation is performed. That is, all writable areas in the microcomputer (43) are cleared, and the magnetron (15), motor (19), compressor (12), and heat insulator (30) are cleared.
) (39), the suction blower (14) is placed in the stopped state, and the exhaust valve (25), the discharge valve (26), and the poppet valve +9) (361) are each placed in the closed state. In step S2, the operation section (44)
In step S3, it is determined by the lower limit level sensor (42) whether the material to be dried (5) has accumulated in the suction hopper (33), and in step S3a, the lower limit level sensor (42) ), it is determined whether a small predetermined amount of the material to be dried (5) is accumulated in the preliminary chamber (29). In step S4, it is checked whether the start flag in the computer (43) is set, and in step S5, it is determined whether the start key is currently being operated by the operation unit (44) based on the input information in step S2. .

Therefore, when melt-molding the object to be dried (5), which is a resin pellet, in order to dry the object to be dried (5) in advance so that such molding can be performed well, first, the operating section (44) is Then, set the desired drying time and drying temperature within the range of 20 to 60 minutes and 70 to 170'C by key operation, respectively.
Then, the continuous switch (47) is turned on. These operating information are input in step S2. After that, the operation section (44
), the information is similarly input in step S2, an affirmative judgment is made in step S5, the start flag is set in step S6, and each of the above-mentioned heat retention is performed in step S7. -ta (30) (3
9) drive control is started. That is, the above preliminary room (29
) and the suction hopper (33) are maintained at approximately the drying temperature set above.
39) is driven intermittently at the desired ratio, thus the reserve i (2
9) and the suction hopper (33) are kept at the above temperature.

Next, steps S8, S9, and S10 are sequentially executed. In step S8, it is checked whether the transport flag in the computer (43) 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 by opening the solenoid valve (10) and driving the compressor (12).
is opened and the suction blower (14) is driven, and the suction action of the blower (14) causes the drying chamber (3) to be drawn from the drying chamber (6).
) is supplied with the to-be-dried*(5), and the motor (19
) is driven, the stirring body (20) rotates, and the drying chamber (3)
The upper surface of the material to be dried (5) supplied inside the container is aligned to a smooth horizontal surface. In the SIO step, the level sensor (23) detects whether the upper surface of the object to be dried (5) has reached the position of this sensor (23) and a predetermined amount of the object to be dried (5) has accumulated in the drying chamber (3). (In this case, it is determined that the predetermined amount has not been accumulated.) 9 After that, S2, S3, S3a, S4, Sll, S8 to S
Each of the 10 steps is executed cyclically. At this time, in the Sll step, the presence or absence of cents in the supply end flag in the computer (43) is checked. When a predetermined amount of the material to be dried (5) accumulates in the drying chamber (3) and this is determined in the SIO step, steps S12 and S13 are then executed. In step S12, the operation of supplying the material to be dried (5) to the drying chamber (3) executed in step S9 is completed.

In step S13, the supply end flag is set.

After that, S2, S3, S3a, S4.811, S14~
Each step of S17 is executed cyclically.

At this time, in step S14, it is checked whether the drying end flag in the computer (43) is set, and in step S15, a drying operation is executed. That is, the temperature sensor (2
Depending on whether the temperature of the material to be dried (5) detected by 4) has reached the set drying temperature, the magnetron (15)
) is driven intermittently, and the material to be dried (5) is maintained at the drying temperature and subjected to microwave drying. In addition, the motor (19) is driven to rotate the stirring body (20), and the object to be dried (5) and the microwave are agitated, so that the object to be dried (5) is evenly dried. Further, the compressor (12) is driven to cool the magnetron (15). Furthermore, in step S15, along with this drying operation, measurement of the elapsed drying time is started. In step S16, the drying time m
1, it is determined whether the set drying time has been reached,
In step S17, as in step S8, it is checked whether or not the transport flag is set.

Therefore, when the elapsed drying time reaches the set drying time, S
After 16 steps, S18 and SL9 steps are executed. In step S18, the drying operation executed in step S15 and the measurement of elapsed drying time are completed, and the measured time is reset. In step S19, the drying end flag is set.

And S17, S2, S3, S3a, S4, S11,
After passing through S14 step, S20, S21, S22, S
Steps 23 and S24 are sequentially executed. In step S20, it is checked whether the discharge flag in the computer (43) is set. In step S21, it is determined whether a small predetermined amount of the material to be dried (5) has already accumulated in the preliminary chamber (29) based on the detection by the level sensor (32). In step S22, if a heat-retaining operation (described later) is being performed in the drying chamber (3), this is terminated and the discharge flag is set. In step S23, if the predetermined amount of material to be dried (5) has not accumulated in the preliminary chamber (29) in step S21, the drying chamber (3) is moved from the drying chamber (3) to the preliminary chamber (29).
This step is executed when the dried material to be dried (5) is allowed to be newly discharged from the drying chamber (3). An operation of discharging to the preliminary chamber (29) is performed. That is, by opening the solenoid valve (27) and driving the compressor (12), the discharge valve (26) is opened and the motor (
19) is subsequently driven to rotate the agitator (20), and as the agitator (20) rotates, the material to be dried (5) near the agitator (20) is pushed to the surroundings, Materials to be dried (5
) is discharged from the discharge valve (26) via the discharge pipe (28) into the preliminary chamber (29).

The material to be dried (5) discharged in this way is stored in the preliminary chamber (29
) has been kept warm since step S7, so
There is no natural cooling, and when it comes to natural cooling, the material to be dried (
5) is prevented from absorbing moisture again. Furthermore, in step S23, the elapsed time of such discharge is started to be counted. In step S24, the discharge elapsed time is a predetermined discharge time (this is a sufficient time to discharge all the predetermined amount of the material to be dried (5) stored in the drying chamber (3)). It is determined whether or not it has been reached.

After that, S2, S3. S3a,,S4,Sll,S14
, S20, S23, S24, and S17 are executed cyclically, and when a small predetermined amount of the material to be dried (5) accumulates in the preparatory chamber (29) as a result of the above-mentioned discharge, steps from S3a to S17 are executed in the circulation. S25, S26, S27, S28
Each step is executed sequentially. In step S25, the transport flag is set, and in step S26, the above-mentioned step S9 is set.
If the drying material supplying operation is being executed by the step, the operation is stopped. In step S27, the suction hopper (33) is transferred from the warmed preliminary chamber (29) to the suction hopper (33).
An operation of transporting the dried material (5) to the container is performed. That is, the solenoid valve (37) is opened and the compressor (1) is opened.
2) opens the poppet valve (36) and drives the suction blower (14), and the suction action of the blower (14) causes drying to be carried from the preliminary chamber (29) to the suction hopper (3)! I'l! Jt5'l is transported. The material to be dried (5) transported in this way is not naturally cooled because the suction hopper (33) has been kept warm since step S7, and the material to be dried is prevented from absorbing moisture again. be done. In step S28, it is determined by the detection by the upper limit level sensor (41) whether the dried material (5) has accumulated in the suction hopper (33) up to the position of the sensor (in this case, it is determined no (34)). ;P, S24, S17,
Each step of S27 and S28 is executed cyclically, and during this time,
The discharge operation to the preliminary chamber (29) and the conveyance operation to the suction hopper (33) are processed in parallel, and the material to be dried (5) discharged to the preliminary chamber (29) is immediately conveyed to the suction hopper (33). Ru.

And 1. When the elapsed discharge time reaches a predetermined discharge time (all the materials to be dried (5) are discharged from the drying chamber (3) to the preliminary chamber (29)), the process continues in S29 and S30.
．． Each step of S31 is executed sequentially. In step S29, the evacuation operation and elapsed elapsed elapsed time measurement performed in step S23 are completed (however, if the compressor (12)
is not stopped because the transport operation is in progress), and the measured time is reset. At S30 step,
All of the above-mentioned supply end flag, drying end flag, and discharge flag are reset. In step S31, the operation section (4
In step 4), it is determined whether the continuous switch (47) is turned on.

In this case, the continuous switch (47) is in the on state, and after passing through the f&s17 step, S4, S11, S8,
Each step of S27.528 is executed cyclically. Then, when the material to be dried (5) in the preliminary chamber (29) is transported and the material to be dried (5) is accumulated in the suction hopper (33) up to the position of the upper limit level sensor (4I), the process starts from step S28.
32.833 steps are executed. In step S32, the conveyance operation executed in step S27 is stopped, and in step S33, the conveyance flag is reset.

The material to be dried (5) accumulated in the suction hopper (33) in this way is melt-molded in the next processing section.
This is the upper limit level sensor (4) inside the suction hopper (33).
An external command signal P for instructing melt molding is sent to the computer (
43) is executed when given within. That is, at this time, the computer (43) opens the on-off valve (40), and the material to be dried (5) is discharged to the suction hopper (33) or the ninth stage processing section. The release valve (40) is closed again when all of the material to be dried (5) in the suction hopper (33) is discharged. Then, the released dried eA (5)
is melt-molded in the next processing section, and in this case, the resin pellet, that is, the material to be dried (5), is dried in advance, so that the molding can be performed well.

Here, if the processing capacity of the next-stage processing section for the melt-forming is slow, the operations from the drying material supply operation to the conveyance operation are performed repeatedly, so that the suction hopper (33) and the preparatory chamber (29) The material to be dried (5) remains accumulated. When the drying material (5) is accumulated in the preliminary chamber (29) and the drying material (5) is to be further discharged from the drying chamber (3), this is determined in step S21. In other words, it is determined that more than a predetermined amount of the material to be dried (5) has accumulated in the preliminary chamber (29) and that it is not permitted to newly discharge the material to be dried (5) from the drying chamber (3) to the preliminary chamber (29). be done. Then, the dried material (5) is left as it is in the drying chamber (3) even after drying. If the drying material (5) is simply left to stand, the material to be dried (5) will naturally cool down and absorb moisture again even after being dried, but in the embodiment of the present invention, step S34 is executed at this time to prevent this. That is, such S3
In step 4, the same control as the drying operation in step S15 is performed, and the object to be dried (5) is kept warm at the set drying temperature using microwaves, so that the object to be dried (5) is kept in the drying chamber (3).
) to prevent moisture from being absorbed again.

Steps are executed, the start flag is reset, and each of the heat retainers (30) (393) is stopped. Thereafter, steps S2, S3, S3a, S4, and S5 are executed in a circular manner.

FIG. 5 shows a flowchart of the stirring body abnormality detection program incorporated in the microcomputer (43),
Such an abnormality detection program is repeatedly executed through appropriate parts of the main operation program shown in FIG. 5 only when the stirring body (20) is rotationally driven. ) abnormality detection will be explained.

First, steps H1 to H6 are executed. In the H1 step, it is checked whether the 2-second timer flag in the computer (43) is set, in the H2 step, the 2-second timer in the computer (43) starts measuring time, and in the H3 step, the 2-second timer flag is set. is set, and in step H4 it is determined whether or not the 2 second timer has counted 2 seconds, and in step H5, 0.
It is checked whether the 5-second timer flag is set, and in step H6, it is checked whether the reed switch (22) is turned on. Then, by setting the 2-second timer flag in step H3, steps H1, 84 to H6 are repeatedly executed.

Therefore, if the stirring body (20) is rotating normally,
Considering that the reed switch (22) is turned on for 0.2 seconds at a 1-second cycle due to such rotation, the reed switch (22) is turned on for 2 seconds while the 2-second timer measures 2 seconds. It is done twice or three times.

Each time it is turned on, the operations described below are executed from step H6. First, steps H7 to HIO are executed. In step H7, 1 is added to the on counter in the computer (43), in step H8, the 0.5 second timer in the computer (43) starts measuring time, and in step H9
In the step, the above O55 second timer flag is set,
In the HIO step, it is determined whether the 0.5 second timer has counted 0.5 seconds. Then, 0 at H9 step
．． By setting the 5 second timer flag, Hl,
H4, H5, and HIO steps are repeatedly executed. Here, when the reed switch (22) is turned on once, it becomes 0.
Since it continues to be on for 2 seconds, if the H7 step is repeatedly executed during this period, an undesired addition will be made in the on counter, and therefore, after the reed switch (22) is turned on and the on counter is incremented once, this will not happen. H is turned on so that addition is not performed, that is, the H7 step is not executed.
The HIO step is executed immediately from step 5. After that, when the 0.5 second timer measures 0.5 seconds, Hll.

Step H12 is executed. 0 in H1l step.
Timing by the 5 second timer is stopped and its time measurement contents are reset, and the 0.5 second timer flag is reset in step H12. Thereafter, the original H1, H4 to H6 steps are repeated again.

In this way, each time the reed switch (22) is turned on, addition processing is performed by the on counter, and the stirring body (22) is added.
0) is rotating normally, the reed switch (22) is turned on two or three times while the two-second timer is counting two seconds, so the on-counter is incremented two or three times. However, the result of this addition is 2 or 3.

When the 2-second timer counts 2 seconds, steps 813 to H16 are sequentially executed from step H4. 8
In step 13, the 2-second timer and 0.5-second timer are stopped and their timing contents are reset, and in step H14, the 2-second timer flag and the 0.5-second timer flag are reset. In step H15, it is determined whether the addition content in the on-counter is 2 or 3. As is now clear, in the present case, the stirring body (20)
It is determined that the content of the on-counter is 2 or 3 based on the normal rotation of the on-counter. At step H16, the contents of the on counter are reset.

Thereafter, the initial execution processing of steps H1 to H6 is repeated.

Now, if an abnormality as described occurs in the stirring body (20), as is clear now, the reed switch (22)
The ON counter is no longer turned on at a 1-second period, and in step H15, it is determined that the content of the on counter is other than 2 or 3, and then steps H17 and H18 are executed. In step H17, the operation of the microwave drying device is stopped, so that the operation is not continued even though the agitator (20) is malfunctioning, and the material to be dried (5) is not uniformly dried. There is no possibility of partial melting resulting in defective products or malfunctions due to this. H
In step 18, the abnormal buzzer (45) and the abnormal light emitting diode (46) are started to drive, and the stirring body (20)
It is reported that the operation has been stopped due to an abnormality.

In addition, based on such notification, the abnormality of the stirring body (20) will be corrected,
After that, when the reset key is operated on the operation section (44), the abnormality buzzer (45) and the abnormality light emitting diode (4) are activated.
6) is stopped, and the device returns to an operable state.

FIG. 7 shows the main structure of a microwave drying apparatus according to an embodiment of the present invention. In this case, microwaves are emitted from an opening (3b) in the bottom wall (3a) of the drying chamber through which the rotating shaft (18) passes. A microwave choke structure (50) provided to prevent leakage is utilized, and a changeover switch (51) is fixed to this negative part. The lever (52) of the switch (51) is hooked on a vertically movable bar (54) that is biased upward by a spring (53), and the upper end of the bar (54) is connected to the stirring body (20). A dielectric spacer (55) suppresses the generation of microwave discharge between the drying chamber bottom wall (3a) and the
) is opposed to the stirring body (20). The spacer (55) is made of a hard material with excellent wear resistance and a very small coefficient of friction.

Therefore, if an abnormality occurs in the stirring body (20), that is, if it comes off the rotating shaft (18) due to some reason, the weight of the stirring body (20) is removed from the vertical movement bar (54). When the bar (54) is released and moved upward by the biasing force of the spring (53), the lever (52) hooked on the bar (54)
moves upward, and the switch (51) switches from NC contact to NC contact.

Here, the switch (51) is for detecting an abnormality in the stirring body (20), and corresponds to the detection means of the present invention.

FIG. 8 shows the circuit of the microwave drying apparatus, in which a microcomputer control section (58) is connected to a commercial power source (56) via a power switch (57), and a microcomputer control section (58) is connected to a commercial power source (56) via a changeover switch (51). A parallel circuit of a controlled section (59), an abnormality buzzer (45), and an abnormality light emitting diode (46) is connected. The controlled part (59) is connected to the No contact of the changeover switch (51), and the parallel circuit is connected to the NC contact of the changeover switch (51).

The microcomputer control section (58) then
The microcomputer (43) of the above-mentioned embodiment, the operation section (44) for inputting various information to the computer, the temperature sensor (24), and the level sensor (231 (32) (4)
1) Consists of (42). The controlled section (59) is
Magnetron (15) and motor (19) of the above embodiment
, exhaust valve (25), compressor (12), heat retainer (
301 (39), suction blower (14), solenoid valve +10
) (27+(37), on-off valve (40), which are controlled by the computer in the control section (58)
It is controlled according to the main operating program shown in the figure.

Therefore, if an abnormality occurs in the agitator (20), the changeover switch (51) switches from the NC contact to the NC contact, so the operation of the microwave drying device is stopped as in the above embodiment. , and this is notified.

In addition, due to an abnormality in the agitator (20), the changeover switch (51)
It may be configured such that only the drive of the magnetron (15) is stopped when the magnetron (15) is not switched.

(G) Effects of the Invention According to the microwave drying apparatus of the present invention, if an abnormality occurs in the stirring means, this can be detected immediately, and therefore the drying operation can be immediately stopped, thereby preventing the drying material from becoming uneven. It is possible to suppress drying and prevent the occurrence of defective products and equipment failure.

[Brief explanation of the drawing]

1 to 6 show one embodiment of the present invention, FIG. 1 is a sectional view, FIGS. 2 and 3 are a sectional view and a plan view of the main parts, respectively, FIG. 4 is a circuit diagram, and FIG. FIG. 5 is a flowchart of the main operation program, FIG. 6 is a flowchart of the agitator abnormality detection program, FIG. 7 is a sectional view of a main part of another embodiment of the present invention, and FIG. 8 is a circuit diagram thereof. (3)...Drying room, (15)...Magnetron, (
20)... Stirring body, (22)... Reed switch,
+51)...Choice switch.

Claims (1)

[Claims] (1) A drying chamber to which a granular or powdery material to be dried is supplied; a microwave supply means for supplying microwaves for microwave drying the material to be dried to the drying chamber; A microwave drying device comprising a stirring means for stirring the material to be dried and the microwave, and a detection means for detecting an abnormality in the stirring means.