JPH0686057B2 - Microwave dryer - Google Patents

Description

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

(B) Conventional technology In Japanese Patent Application No. 1-47803, microwaves are supplied to a drying chamber in which a granular or powdery material to be dried is supplied, and the material to be dried is microwaved uniformly. There is disclosed a microwave drying device for stirring an object to be dried so that various microwave drying is performed.

However, in this case, the power supply port for supplying the microwave to the drying chamber is formed on the side wall of the drying chamber, and the microwave permeable cover covering the power supply port is located on the side wall of the drying chamber. Further, the material to be dried is scattered sideways by stirring.
Therefore, at the time of stirring, the material to be dried frequently hits the cover located on the side wall of the drying chamber, and there is a drawback in that the cover is heavily worn.

Also, when cleaning the inside of the drying chamber, if it is on the side wall, the magnetron will be hot immediately after the drying operation, so there is a risk that a person who cleans it may touch and burn it.

(C) Problem to be Solved by the Invention The present invention is intended to provide a microwave drying device in which a car covering a microwave power feeding port is less likely to be worn, and maintenance such as cleaning can be performed safely.

(D) Means for Solving the Problems The microwave drying apparatus of the present invention has an upper opening, and a drying chamber to which granular or powdery material to be dried is supplied, and the material to be dried in the drying chamber are agitated. A stirring unit, a door that opens and closes the upper opening of the drying chamber for maintenance such as cleaning of the upper drying chamber, a power supply port provided in the door, and a door fixed to the door, and the drying from the power supply port. A microwave oscillating means for supplying microwaves to the room and a microwave transparent cover for covering the power feeding port are provided.

(E) Action That is, the power supply port is provided on the door that opens and closes the upper opening of the drying chamber, and the cover that covers the power supply port is located on the door corresponding to the upper wall of the drying chamber. Therefore, the material to be dried easily scatters in the lateral direction during stirring, but does not easily scatter upward, the frequency of contacting the material to be dried with the cover located on the upper door is low, and the cover is not easily worn.

Also, when performing maintenance such as cleaning of the drying chamber, the door that closes the upper opening of the drying chamber is opened and moved to the side away from the person doing the maintenance, so there is no danger of hitting the magnetron and getting burned. It's safe.

(V) Embodiments FIGS. 1 to 4 show 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 main body of the drying device body (1) is a cylindrical drying chamber (3) whose upper opening (3a) is opened and closed by a door (2).
Is provided. 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). 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).

A suction hopper (7) is connected and fixed to the door (2) of the drying chamber (3). The material to be dried (5) is placed in the hopper.
Filter wire mesh (8
a) and the filter paper (8) are arranged and a poppet valve (9) is provided above the filter paper. A suction blower (11) is connected to the suction hopper (7) above the poppet valve (9) via an intake pipe (10). In this case, when the blower (11) is driven with the poppet valve (9) being driven to open, the intake action of the blower (11) causes the intake pipe (1).
0), the suction hopper (7) and the drying chamber (3) to the supply pipe (4), and the material to be dried (5) in the storage tank (6) passes through the supply pipe (4) to the drying chamber (5). 3). When the material to be dried (5) reaches the drying chamber (3), it falls by its own weight and accumulates therein.

A supply port (2a) is further formed in the door (2), and a microwave oscillating means, that is, a magnetron (12) is provided via a waveguide (13) communicating with the power supply port (2a). It is fixed. A cooling fan (12a) for supplying cooling air to the magnetron (12) is also fixed. The microwave from the magnetron (12) is supplied into the drying chamber (3) via the waveguide (13) and the power supply port (2a).
The power supply port (2a) is covered with a microwave transparent cover (2b).

In the drying chamber (3), the bottom wall is provided with an agitator (15) driven by a motor (14) to agitate the material to be dried (5), and the side wall is provided with a level sensor (16) and a thermistor. A temperature sensor (17) such as a stat is arranged. The bell sensor (16) detects whether or not a predetermined amount of the dried material (5) has accumulated in the drying chamber (3), and the temperature sensor (17) detects the temperature of the material to be dried (5). Further, a compressor (19) is connected to the left bottom portion of the drying chamber (3) via an intake valve (18), and an exhaust valve (20) is further connected to the door (2) of the drying chamber (3) correspondingly. ) Is provided. The driving of the compressor (19) and the opening of the intake valve (18) and the exhaust valve (20) are performed when the material to be dried (5) is dried by microwaves, and the steam generated during the drying is compressed. (1
It is discharged to the outside through the exhaust valve (20) together with the air from 9).

A discharge valve (21) is provided on the right bottom of the drying chamber (3), and the discharge valve is opened when discharging the dried object (5). 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 level sensor (26)
Is normally rotated by rotating the rotating body (25), and a small predetermined amount of the object to be dried (5) is accumulated in the auxiliary chamber (23) to rotate the rotating body (25). When 5) is a load and the rotating body (25) cannot be rotated satisfactorily, a predetermined signal is output to detect that the material to be dried (5) is accumulated in 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 (29a) 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 portion of the poppet valve (30), the suction hopper (2
7) through the intake pipe (31) to the intake blower (1
1) are connected. In this case, when the blower (11) is driven with the poppet valve (30) open, the intake action of the blower (11) causes the transfer pipe (28) to pass through the intake pipe (31) and the suction hopper (27). ), The material to be dried (5) accumulated in the preliminary chamber (23) passes through the transfer pipe (28) and reaches the suction hopper (27). When the material to be dried (5) reaches the suction hopper (27), it falls into the hopper by its own weight.

In the suction hopper (27), the heat retaining heater (32) is arranged on the lower inclined wall, the opening / closing valve (33) is provided on the lower end, and the upper and lower limit level sensors (34) are provided on the upper and lower parts.
(35) is located. When the on-off valve (33) is closed, the intake action acts to drop the material to be dried (5) in the suction hopper (27), and the material to be dried (5) accumulates in the suction hopper (27). When the opening / closing valve (33) is opened, the material to be dried (5) thus accumulated falls downward to reach the next-stage processing section, that is, the material to be dried (5) dried in the processing section, that is, Resin pellets are melt molded.

In order to explain the opening / closing mechanism of the door (2), the bearing body (36) is fixed to the side wall of the drying chamber (3), and the bearing body (36) has a large upper diameter portion. A through hole composed of (37) and the lower diameter small portion (38) is formed. The inner surface of the lower diameter small portion (38) is threaded. on the other hand,
A screw shaft (41) having a fixed handle (39) on the upper part and a screw part (40) on the lower part is provided.
The screw part (40) at the lower part of 1) is screwed into the small diameter part (38) at the lower part. The pipe shaft (43) is supported on the screw shaft (41) by a bearing portion (42) fixed to the screw shaft (41), whereby the pipe shaft (43) rotates with respect to the screw shaft (41). It is free to move. Such a pipe shaft (4
The lower part of 3) reaches inside the large diameter part (37). An arm body (44) is fixed to the pipe shaft (43), and the arm body (44) is fixed to the upper surface of the door (2) at the tips (45) (45). .

In such a door opening / closing mechanism, when the door (2) is opened, the handle (39) is first moved counterclockwise (second
(Fig.) Then, based on the screwing relationship between the screw part (40) and the lower diameter small part (38), the screw shaft (41) moves upward while rotating, and the bearing part (42) accordingly moves. By pushing (43) upward, the pipe shaft (4
3) also moves upward, so that the arm (4
The door (2) connected via 4) moves up. Then, the door (2) is manually operated to rotate the pipe shaft (43) with respect to the screw shaft (41) to move the door (2) to the position indicated by the broken line in FIG. Is completed, and the upper opening (3a) of the drying chamber (3) is opened. In this state where the door (2) is opened, it is easy to remove the agitator (15) and it is very easy to clean the drying chamber (3). In the opening operation, the opposite work may be performed.

Now, in the above-mentioned structure, the power supply port (2a) is formed in the door (2) that opens and closes the opening (3a) of the drying chamber (3), and the cover (2b) covering this power supply port (2a). Is located on the door (2) corresponding to the upper wall of the drying chamber (3).
Therefore, the material to be dried (5) easily scatters laterally when stirred by the stirrer (15), but it is difficult to scatter upwards, and the cover (2b) located on the upper door (2) is dried. The frequency with which the object (5) hits is low, and the cover (5) does not easily wear.

FIG. 5 shows a circuit of the microwave drying device, and a microcomputer (46) of Sanyo Denki Co., Ltd. product number LC-65PG23 is provided as a main control unit, and the computer is a drying device body (1). Information from the operation section (47) arranged on the front surface of the vehicle, temperature information from the temperature sensor (17), and various level sensors (16) (26) (34) (3)
5) Based on the information from the above, etc., the magnetron (1
2), cooling fan (12a), motor (14), intake valve (1
8), exhaust valve (20), compressor (19), discharge valve (2
1) The heat insulation heaters (24) (32), the suction blower (11), the poppet valves (9) (30), and the opening / closing valve (33) are drive-controlled.

FIG. 6 shows a flow chart of an operation program incorporated in the microcomputer (46), 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,
4 and S5 are cyclically executed. In step S1, initial setting operation is performed. In other words, all the writable areas in the microcomputer (46) are cleared, and the magnetron (12) and the cooling fan (12) are
a), the motor (14), the compressor (19), the heat insulation heaters (24) (32), the suction blower (11) are placed in the drive stopped state, and the intake valve (18), the exhaust valve (20), the exhaust valve (2
1), the poppet valves (9) (30) and the open / close valve (31) are placed in the closed state. In S2 step, operation information from the operation section (47) is input, and in S3 step, it is judged by the lower limit level sensor (35) whether or not the material to be dried (5) is accumulated in the suction popper (27). , In step S3a, it is determined whether or not a small amount of the material to be dried (5) is accumulated in the preliminary chamber (23) based on the detection of the level sensor (26). In step S4, it is checked whether or not the start flag is set in the computer (46). In step S5, it is determined whether or not the start key is currently operated by the operation section (47) based on the input information in step S2. It

Thus, when the material to be dried (5), which is a resin pet, 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 (47) is hand,
Within the range of 20 to 60 minutes and within the range of 70 to 170 ° C., the desired drying time and drying temperature key are set and the continuous switch (48) is turned on. These operation information are input in step S2. After that, when the start key is operated on the operation unit (47), such information is similarly input in step S2, an affirmative judgment is made in step S5, the start flag is subsequently 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 the step, it is checked whether or not the transport flag in the computer (46) 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, and the substance to be dried (5) is supplied from the storage tank (6) into the drying chamber (3) by the suction action of the blower (11), Moreover, the agitator (15) is rotated by driving the motor (14), and the upper 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).

After that, the steps S2, S3, S3a, S4, S11, and S8 to S11 are cyclically executed. At this time, in step S11, it is checked whether or not the supply end flag is set in the computer (46). 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 supply end flag is set in the computer (46), 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 material to be dried (5) detected by the temperature sensor (17) reaches the set drying temperature (at this time, the magnetron (1)
The cooling fan (12a) is driven to cool (2)), the material to be dried (5) is microwave-dried while being maintained at the drying temperature, and the motor (14) is re-driven to stirrer (15). )
Is rotated so that the material 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 to dry the material to be dried. (5)
Water vapor generated from the water is discharged to the outside. 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 reaches the set drying time, and S1
In step 7, as in step S8, it is checked whether the transport flag is set.

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 of the drying operation and the elapsed time of drying executed in step S15 is ended, and the time counted is reset. 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 step S23, the material to be dried (5) is placed in the preliminary room (23) in step S21.
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 slight predetermined amount of the material to be dried (5) is accumulated in the preliminary chamber (23) as a result of the discharge, 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 dried hopper (27) conveyed in this way from the above step S7, it does not cool naturally and prevents the dried object from absorbing moisture again. It 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, S1
1, S14, S20, S23, S24, S17, S27, S28 are 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 into 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 or not the continuous switch (48) is turned on in the operation section (47).

In the present case, the continuous step (48) is in the ON state, and after the step S17, the steps S4, S11, S8, S27 and 28 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 melt-molded in the next-stage processing section. This is executed when an external command signal P for commanding melt molding is applied to the computer (46) 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 (33) is opened by the computer (46), 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),
When the material to be dried (5) is about to be discharged from the drying chamber (3), this is determined in step S21, that is, the preliminary chamber (2
It is determined that the material to be dried (5) is accumulated in the predetermined amount more than the predetermined amount in 3), and it is not allowed to newly discharge the material to be dried (5) from the drying chamber (3) to the preliminary 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 (48). That is, when the step S31 is executed at the time of turning off, the step S35 is then executed, the start flag is reset, and the heat retention heaters (24) (32) are stopped. Then S2, S3, S3a, S
4, S5 step is cyclically executed.

(G) Effect of the Invention According to the present invention, it is possible to provide a practical microwave drying device in which the cover that covers the microwave feeding part is less likely to wear.

Incidentally, in the present embodiment, the power supply port (2a) has the door (2).
It is not formed on the curved side wall of the cylindrical drying chamber (3), and therefore it is difficult to attach the cover (2b) and the waveguide (13) to such a curved side wall. It is not necessary and is practical in this respect as well.

In addition, when performing maintenance such as cleaning the inside of the drying chamber, there is no worry of burns, and safe work can be performed.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a sectional view, FIG. 2 is a plan view of an essential part, FIG. 3 is a sectional view taken along line III-III of FIG. 2, and FIG. 4 is IV of FIG. -IV line sectional view, FIG. 5 is a circuit diagram, 6
The figure is a flow chart of the operation program of the microcomputer. (3a) …… Top opening, (2) …… Door, (3) …… Drying room, (2a) …… Power supply port, (12) …… Magnetron, (2
b) …… Microwave transparent cover, (15) …… Stirrer.

Continuation of the front page (56) Reference JP-A 64-58511 (JP, A) JP-A 61-262585 (JP, A) JP-A 48-95456 (JP, A) JP-A 60-31919 (JP , A)

Claims (1)

[Claims] 1. A drying chamber having an upper opening to which a granular or powdery material to be dried is supplied, a stirring means for stirring the material to be dried in the drying chamber, and maintenance such as cleaning of the drying chamber. A door for opening and closing the opening of the drying chamber for
A power supply port provided on the door; a microwave oscillating unit fixed to the door for supplying microwaves into the drying chamber from the power supply port; and a microwave transparent cover for covering the power supply port. Microwave drying device characterized by.