JPH07101150B2 - Vacuum dryer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vacuum drying apparatus used for drying a bulk material.

[Prior art and its problems]

For example, in the continuous vacuum drying device described in Japanese Patent Publication No. 55-30195, a spiral component transfer track is wound around and fixed to the outer periphery of a central cylindrical body, and a torsional vibration drive unit is provided below the track. A so-called vibrating spiral elevator in which is arranged is used, and the whole is covered with a tank, and the inside of this tank is made into a vacuum state, and the spiral track is dried by the driving of the torsional vibration drive section. When the track is transferred to the upper end of the truck, a branch pipe extending in a generally "U" shape protrudes outward from the tank at its upper end, and the lower end is inserted again into the tank. Has been done. For this reason, a vacuum seal is required to maintain the vacuum in the tank in order to lead the branch pipe to the outside of the tank and to introduce it into the tank. A switching damper is disposed in the "V" -shaped branch pipe, and when the bulk material is dried to a desired degree, the switching damper is opened to open the branch pipe from the upper end of the spiral track. The introduced material is discharged to the outside by switching the switching damper. Therefore, in order to maintain the degree of vacuum in the tank even when discharging from the switching damper to the outside, various vacuum sealing devices must be used on the downstream side.

In the above-mentioned conventional apparatus, a supply pipe is fixed in the tank via a sealing device in order to supply the bulk material to be dried to the lower end of the truck of the vibrating spiral elevator in the closed tank. As described above, in the conventional device, a vacuum sealing device is required in each place, and not only the number of parts is increased, but also the cost of the entire device is significantly increased. Further, the so-called oscillating spiral elevator is entirely covered with a closed tank, and the configuration of the torsional oscillating drive portion is not particularly specified, but a pair of oscillating motors are generally used. As is well known, this oscillating motor has unbalanced weights provided at both ends of the rotary shaft of the induction motor, and this rotation causes each oscillating motor to generate a centrifugal force. Although different slips should occur respectively, a so-called synchronizing force acts to generate a torsional vibration force. However, as is well known, the oscillating motor stores grease or oil, or in some cases, oil for cooling, in order to ensure smooth rotation in the bearing or the rotating part to support the rotating shaft at both ends. ing. When such a torsional vibration drive unit is placed under vacuum, if the drive is continued for a long time, especially if it is continued for a long time, the temperature of the whole becomes high due to coil heat, etc. Therefore, the gas of oil or grease is released into the vacuum and the degree of vacuum is reduced. Not only does it worsen, but if the material to be dried is food, it contaminates it and reduces its quality.

[Problems to be solved by the invention]

The present invention has been made in view of the above problems, and a vacuum that can prevent the adverse effect of the torsional vibration drive section under vacuum and dry even if the bulk material to be dried is a food product without degrading its quality. An object is to provide a drying device.

[Means for solving the problem] In a vacuum drying device in which a bulk material is transferred by circulating vibration on a spiral track in a closed tank under reduced pressure and dried by circulating, The drive unit is arranged in the atmosphere, and an opening is formed at the upper end of the spiral track, and a guide chute extending downward is connected to the opening, and the lower end of the guide chute is at the lower end of the spiral track. A bulk material is provided on the spiral track through the opening of the spiral track and the guide chute only in the closed tank that receives the torsional vibration force of the torsional vibration drive. It is circulated and dried by dropping it to the lower end, and the torsional vibration is applied to the lower end of the closed tank. A material discharge opening is formed on the downstream side with respect to the transfer direction of the loose material, and a gate plate that hermetically closes the material discharge opening is provided, and the dried loose material is opened by opening the gate plate and is subjected to the torsional vibration. This is achieved by a vacuum drying device characterized in that the material is discharged to the outside through the material discharging opening.

[Action]

Since the torsional vibration drive unit is insulated from the closed tank and placed in the atmosphere, it does not lower the vacuum in the closed tank even if the temperature of the drive increases and the gas of oil or grease is released. . Moreover, the bulk material in the closed tank is not contaminated. In addition, under vacuum, the bulk material is circulated in a closed tank by repeated up and down movements on the spiral track and on the guide chute, so that the entire material is uniformly stirred and dried uniformly and quickly. Further, the dried bulk material is discharged to the outside from the material discharge opening arranged at the lower end of the closed tank by the centrifugal force caused by the torsional vibration.

〔Example〕

Hereinafter, a circulation type vacuum drying device according to an embodiment of the present invention will be described with reference to the drawings.

1 to 4 show the first embodiment. In these drawings, the circulation type vacuum drying device is indicated by (1) as a whole and comprises a vacuum drying section (2) and a torsional vibration driving section (3).
The vacuum drying section (2) is supported by columns (6) standing on a base (8) via a vibration-proof coil spring (7) fixed to the bottom thereof. Further, the vibration drive unit (3) is driven by inclining the drive unit mounting plate (4), which is hung and fixed to the bottom wall of the vacuum drying unit (2), at a certain angle in opposite directions with respect to the vertical axis. It is composed of a pair of vibration motors (5a) (5b) fixed to both surfaces of the part mounting plate (4). Vibration motor (5
As is well known, in (a) and (5b), a semi-circular weight is fixed to both ends of the rotary shaft of the induction motor, and when this is driven, an oscillating force is generated by the centrifugal force of the semi-circular weight.
Further, since it is fixed by inclining at a constant angle in opposite directions to the vertical axis, a torsional vibration force is generated around the vertical axis. As a result, the vacuum drying section (2) is capable of torsional vibration.

Next, details of the vacuum drying unit (2) will be described.

In the vacuum drying section (2), a track (10) having a substantially U-shaped cross section is spirally wound around and fixed to the inner peripheral wall surface of the substantially cylindrical body (9), and is formed in the center. A cylindrical body (12) is arranged in the space fixed to the bottom surface of the main body (9) by, for example, welding. The coil (11) of the electric heater is wound around the cylindrical body (12). Although not shown, it is assumed that a power source is connected to the coil (11). The heating source is not only the coil (11) but also the track (1
As shown in FIG. 3) of (0), the heater (20) is continuously provided over almost the entire bottom surface.

An opening (60) is formed at the upper end of the track (10) configured as described above, and a guide chute (13) for guiding the material from the upper end of the track 10 to the lower end of the track 10 is formed in the opening (60). ) Is integrally fixed, and is supported at the lower end of the guide chute (13) by a column (14) fixed to the bottom surface of the main body (9) to stabilize the attachment. Further, the supply / discharge opening (21) is provided at the lower end of the main body (9).
The gate plate (22) is fixed to the gate plate (22) by the bolts (24) through the seal member (23), from which the material is supplied and discharged. The upper opening of the main body (9) is covered with a circular lid (15) via a ring-shaped seal plate (25), and is fixed to the main body (9) at its outer peripheral edge by bolts (26). There is. In this way, the inside of the main body (9) is sealed, but the lid (15) is provided with a pair of viewing windows (16) (17), to which a transparent plastic plate is attached. The flow of material and the dry state in the main body (9) can be observed with the naked eye.
Further, the lid (15) is provided with two holes (27) and (28), and one hole (27) is attached with a vacuum gauge (18), so that the degree of vacuum in the main body (9) is increased. It is designed to detect A flexible pipe (19) is connected to the other hole (28), which is connected to a vacuum pump via a solenoid valve (not shown). The inside of the main body (9) is evacuated by opening the vacuum pump and the solenoid valve.

The vacuum drying apparatus according to the embodiment of the present invention is configured as described above, and its operation will be described below.

Although not shown, powder (coffee beans) to be dried is stored near the downstream end of the spiral track (10) of the main body (9). Further, the inside of the main body (9) is kept under a predetermined reduced pressure via a pipe (19) by a vacuum pump (not shown). The vacuum gauge (18) detects whether or not the pressure is reduced to a predetermined level, and drives the pair of vibration motors (5a) (5b) under the predetermined reduced pressure. As a result, a torsional vibration force is generated, the body (9) supported by the coil spring (7) undergoes a known torsional vibration, and the material to be dried runs along the spiral track (10) along it. Be transferred.
During this transfer, the material is heated by the coil (11) wound around the outer periphery of the cylindrical body (12) and the heater (20) arranged on the bottom wall of the track (10). Further, the vacuum state promotes the evaporation of the water content of the material, and the latent heat of evaporation is replenished by the coil (11) and the heater (20), so that the material is heated and dried more efficiently. Further, when the material is transferred on the spiral track (10) and reaches the upper end of the spiral track (10), the material falls into the opening (60) and passes through the guide chute (13) connected to the opening (60). It is returned to the lower end of the truck (10). Then, the material goes up again on the spiral track (10) by the torsional vibration force, and is dried by the drying action by the above-mentioned vacuum and heating. Therefore, the material is repeatedly moved up and down on the spiral track (10) and the guide chute (13) while being dried, and circulates in the main body (9). At this time, since the material is transferred under reduced pressure, the material is transferred at a higher transfer speed than in the case where the material is transferred by applying a torsional vibration force at the same amplitude and the same frequency in the atmosphere. Therefore, the circulation speed can be increased and the heating and drying operations can be performed. Further, since the entire material is agitated by the circulation and transfer of the material, it is possible to efficiently perform the heating and drying operations.

After heating and drying for a predetermined time, the gate plate (22) arranged below the main body (9) is removed by removing the bolt (24). As a result, the material circulating in the main body (9) is discharged to the outside of the main body (9) through the supply / discharge opening (21) before being transferred upward along the track (10) again. Although not shown, a guide chute can be attached to the supply / discharge opening (21). When all the material is discharged from the inside of the main body (9) and becomes empty, a new material to be dried is supplied into the main body (9) through a guide chute for introduction while applying a torsional vibration force from a supply / discharge opening (21). . The material supplied through the supply / discharge opening (21) ascends in the spiral track (10) by the torsional vibration force and is finally filled in the main body (9) to a required level. After the filling, the gate plate (22) is attached by the bolts (24), and the material to be dried in the main body (9) circulates in the main body (9) while being heated and dried as described above.

The operation of the embodiment of the present invention has been described above. Next, this effect will be described.

Since the material is transferred by vibration in vacuum, as compared with the transfer of torsional vibration in the atmosphere as described above, the transfer speed is high and the drying efficiency is high even with the same vibration force. or,
Assuming the circulation transfer on the spiral track (10) and the guide chute (13), the material is evenly stirred, and at the same time, a heater (20) and a heater (20) arranged on the bottom surface of the track (10) are provided. Since the material is heated by the coil (11) wound around the outer periphery of the cylindrical body (12), the entire material can be efficiently and uniformly dried. Further, since the heating and drying is performed in a vacuum, it is possible to further improve the drying efficiency as compared with the heating and drying in the atmosphere in combination with the improvement of the transfer rate described above. Furthermore, since all the dried material in the main body (9) is discharged to the outside from the supply / discharge opening (21) by the centrifugal force generated by the torsional vibration, the next material to be dried can be easily replaced. It can be done reliably.

Since grease is applied to the bearing and varnish is applied to the coil inside the vibration motor, when the vibration motor is heated by operating for a long time, gas is discharged from the inside of the motor. In the past, since the vibration motor was also placed in a vacuum, the released gas deteriorates the degree of vacuum and deposits on the material to be dried, and in some cases deteriorates the quality of the material, or heats and dries it. It was supposed to reduce the action. However, according to this embodiment, since the vibration motors (5a) and (5b) are arranged in the atmosphere, the vibration motors (5a) and (5b) are cut off from the material to be heated and dried, so that the above-mentioned drawbacks are not present.

FIGS. 5 and 6 show a circulation type vacuum drying device (31) according to the second embodiment, which is also composed of a vacuum drying section and a torsional vibration driving section, like the apparatus of the first embodiment. It The second embodiment differs from the first embodiment in that the heating heater is arranged outside the vacuum chamber. Therefore, the configuration will be described below. Also, the parts corresponding to those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

The vacuum drying section (32) has a track (38) having a substantially U-shaped cross section that is spirally wound around and fixed to an inner peripheral wall surface of a cylindrical main body (33), and is formed in a space formed in a central portion. Is a cylinder (3
6) is airtightly fixed to the bottom surface of the main body (33), and the ring-shaped upper opening formed by the main body (33) and the cylindrical body (36) is inserted through the ring-shaped seal plate (25). It is covered with a ring-shaped lid (35) and is fixed to the main body (33) at the outer peripheral edge by bolts (26). Similarly, the flange portion (36a) of the cylindrical body (36) also has a sealing plate. It is fixed to the inner peripheral edge of the lid (35) with a bolt.
Therefore, the cylindrical wall of the main body (33), the cylindrical body (36) and the lid (35).
The doughnut-shaped vacuum chamber (airtight chamber) is constituted by the donut-shaped vacuum chamber, and the spiral track (38) is arranged in the donut-shaped vacuum chamber. Opening (61) at the top of the track (38)
The guide chute (39) for guiding the material to the lower side of the track (38) is integrally fixed to the opening (61). Further, as in the first embodiment, a supply / discharge opening (21) is formed in the lower portion of the main body (33), and the gate plate (22) is fixed to this through a seal member (23) by a bolt (24). The material is supplied and discharged from here.
Further, the peep window (16) is formed on the lid (35) as in the first embodiment.
(17), a vacuum gauge (18), and a pipe (19) connected to a vacuum source via a solenoid valve. The heating coil (34) is wound around the outer peripheral wall of the main body (33), and the other heating coil (37) is wound around the coil support (40) on the inner side of the cylindrical body (36). Are installed. The flange portion (40a) of the coil support body (40) is fixed to the lid (35) by bolts. Therefore, the coils (34) (37) are arranged outside the vacuum chamber.

Next, the circulation type vacuum drying device (3
The action and effect of 1) will be explained. Since the action of circulating the material in the vacuum chamber is the same as in the first embodiment, the heating method will be described. Similar to the first embodiment, the material is subjected to the drying action by the vacuum state and the heating, and is repeatedly moved up and down on the spiral track (38) and the guide chute (39) to circulate in the body (33). However, in the first embodiment, since the heating coil and the heater, which are the heating means, are installed in the vacuum chamber, when the coil and the heater are in a heated state, gas is released from the insulating material of the electric wires forming them. As a result, the gas may deteriorate the quality of the material to be dried. In the second embodiment, since the coils (34) (37) as heating means are arranged outside the vacuum chamber, it is possible to give only pure heat to the material to be dried and to give the released gas. Absent. Therefore, it becomes possible to obtain a dried material of higher quality.

FIG. 7 shows a vacuum dryer (50) according to a third embodiment of the present invention.
However, the parts corresponding to those in FIGS. 1 to 6 are designated by the same reference numerals and the detailed description thereof will be omitted.

That is, in the above embodiments, the main body is cylindrical, and the spiral track is wound around and fixed to the inner peripheral wall surface, but according to the present embodiment, the cylindrical tube pair (55) serves as a closed tank. Although it is used under reduced pressure, only the spiral track portion of the so-called vibrating spiral elevator is placed under reduced pressure inside this. The entire torsional vibration drive section is arranged in the atmosphere. A central cylinder (51) fixed to the upper end of the torsional vibration drive is located in the closed tank (55), and a spiral track (52) is wound around and fixed to the outer periphery of the central cylinder (55). And from this upper end, the lower end of the spiral track (52), that is, the ascending opening (52
It is arranged so as to face a). Therefore, the material fed from the material feeding / discharging port to a certain level rises up the spiral track (52) by the drive of the torsional vibration drive unit. It is possible to perform vacuum drying by repeating the circulation after falling to (52a), and since the heating coil (54) is attached to the outer periphery of the tank (55), the vacuum drying can be performed. In addition, it is possible to prevent adverse effects from this coil. The other functions and effects are the same as those in the above-described embodiment, and will not be described.

Although the embodiments of the present invention have been described above, the present invention is not limited to these and various modifications can be made based on the technical idea of the present invention.

For example, although a pair of vibration electric motors are used as the torsional vibration driving unit in the above embodiments, the present invention is not limited to this. For example, an electromagnet is used to fix this on the base, and the sealed tank and the base are inclined at equal angular intervals. A so-called electromagnet-type torsional vibration drive unit may be used by connecting the plate springs provided. It is clear that other known torsional vibration drives can be used.

Further, in the above embodiments, the heating source is arranged inside and / or outside the tank in order to promote the drying in the vacuum.
This may be omitted.

Further, in the above embodiments, the common supply / discharge port was used for supplying the material into the tank and for discharging the material, but instead of this, the supply port and the discharge port may be separately provided. . For this reason, one extra sealing means (vacuum seal) is required, but even with this, the number of sealing means can be far reduced compared with the conventional device, and the cost of the entire device can be reduced. it can.

Further, in the above first and second embodiments, a spiral track is formed on the inner peripheral wall surface of the closed tank, and the material is lifted up and guided from the opening at the upper end of the track to the lower end of the track by the guide chute for circulation. In the third embodiment, only the spiral track wound around the central cylindrical portion of the known vibration spiral elevator is arranged in the closed tank, and the track is formed on the inner peripheral wall surface of the closed tank. Although not provided, in the structure shown in FIG. 7, a spiral track is further formed on the inner peripheral wall surface of the closed tank as in the first and second embodiments, and this is also transferred by the common torsional vibration drive section. In this way, the circulation efficiency may be further increased.

Furthermore, in the third embodiment, a so-called central cylindrical body (51) is used, and a spiral track (52) is wound around the outer periphery of the central cylindrical body (51). The material transferred from the upper end of the spiral track (52) is introduced into this opening and dropped vertically to the lower end of the spiral track (52) wound around the outer periphery of the cylindrical body (51). You may lead to the department. That is, the guide chute (53) in FIG. 7 can be omitted.

Further, in the above embodiments, the closed tank is made of an opaque body and the peep window is formed on the lid. However, the whole closed tank may be made of a transparent material so that it can be observed at any position from the outside. For example, high heat resistant glass may be used.

Further, in the above-mentioned examples, it was explained that the heating was performed batchwise by vacuum heating and drying, and if the desired degree of dryness was obtained, the material was discharged to the outside through the supply / discharge port. In such cases, it is necessary to cool this.
For this purpose, a flexible pipe may be connected to the supply / discharge port and lead to the cooling device.

Further, in the above embodiments, when the heating source is used, the electric heater is explained, but far infrared rays may be used instead. In this case, for example, the far infrared ray emitting material may be attached to the side wall portion of the spiral track, or the far infrared ray emitting material which also extends spirally may be attached above the track. .

〔The invention's effect〕

As described above, according to the vacuum drying apparatus of the present invention, the torsional vibration driving section is arranged in the atmosphere, so that the adverse effect of the emitted gas generated from this does not affect the bulk material to be dried, and , Without reducing the degree of vacuum in the closed tank, and by the guide chute connected to the opening provided at the upper end of the spiral track,
The material is guided to the lower end of the track to ensure that the material can be circulated only in the closed tank, which allows the material to be agitated throughout and dried quickly and evenly. The device cost can be greatly reduced without requiring a large number of devices. In addition, the quality of the bulk material to be dried can be guaranteed and dried. Furthermore, since the material is transferred by vibration under reduced pressure, the transfer speed can be further increased under the same torsional vibration condition depending on the quality of the bulk material. Furthermore,
The dried bulk material is forcibly discharged to the outside from the material discharge opening under the centrifugal force caused by the torsional vibration, so that the dried bulk material does not remain in the closed tank,
It can be reliably discharged to the outside, and replacement with the next loose material to be dried can be performed easily and reliably.

[Brief description of drawings]

FIG. 1 is a side view of a vacuum drying apparatus according to a first embodiment of the present invention, FIG. 2 is a plan view of the same, and FIG. 3 is a III-I in FIG.
II line sectional view, FIG. 4 is a IV-IV line sectional view in FIG. 3, FIG. 5 is a partially cutaway side view of the vacuum drying apparatus according to the second embodiment of the present invention, and FIG. 6 is FIG. 6 is a sectional view taken along line VI-VI in FIG. 7 and FIG. 7 is a partially cutaway side view of the vacuum drying apparatus according to the third embodiment of the present invention. In the figure, (1) (31) (50) …… vacuum dryer (3) …… torsional vibration drive section (10) (38) (52) …… track (13) (39) (53) …… Guide chute (60) (61) …… Opening

Claims (2)

[Claims] 1. A vacuum dryer in which a bulk material is transferred by torsional vibration on a spiral track in a closed tank under a reduced pressure and is circulated to dry the material. And an opening is formed in the upper end of the spiral track, and a guide chute extending downward is connected to the opening, and the lower end of the guide chute looks into the lower end of the spiral track. The bulk material is dropped on the spiral track through the opening of the spiral track and the guide chute to the lower end of the spiral track only in the closed tank that receives the torsional vibration force of the torsional vibration drive. Therefore, the bulk material is circulated and dried, and the loose material is transferred to the lower end of the closed tank by the torsional vibration. A material discharge opening is formed on the downstream side with respect to the direction, and a gate plate that hermetically closes the material discharge opening is provided, and the dried loose material passes through the material discharge opening by the torsional vibration by opening the gate plate. The vacuum drying device is characterized in that it is discharged outside. 2. The closed tank is cylindrical, and the spiral track is wound around and fixed to an inner peripheral wall surface of the closed tank, and a heater is provided over substantially the entire bottom surface of the spiral track. The vacuum dryer according to (1).