JP4132462B2 - Drying device for powder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drying apparatus for a granular material, and more particularly to a drying apparatus for drying a granular material such as a resin pellet.
[0002]
[Prior art]
Conventionally, as a drying apparatus for drying granular materials such as resin pellets, for example, a dehumidifying dryer in which a hopper dryer, a dehumidifier, a blower, a heater, and the like are connected by a closed line is used. It is widely used because it can efficiently remove moisture.
[0003]
In such a dehumidifying dryer, since it is necessary to dry the granular material at a stretch to a certain level of humidity, it is necessary to provide a dehumidifier having a large capacity.
[0004]
However, if a dehumidifier having a large capacity is provided, the apparatus becomes large, consumes a lot of energy, and increases the running cost. For example, in Japanese Patent Application Laid-Open No. 11-90932, a main hopper dryer of a dehumidifying dryer is used. , Connect the hopper dryer for pre-drying of the hot air dryer, first supply the granules to the pre-dry hopper dryer to remove the moisture immediately after the start of drying, and then remove the moisture from the It has been proposed to supply energy to a hopper dryer for dehumidification and drying, thereby enabling the use of a dehumidifier having a small capacity, thereby saving energy.
[0005]
[Problems to be solved by the invention]
However, in the drying apparatus described in JP-A-11-90932, it is possible to save energy by using a dehumidifier having a small capacity, but on the other hand, the dried granular material is used. Depending on the application, the drying may not be sufficient yet. For example, when a dried resin pellet is molded, a mold or the like may be soiled due to poor drying.
[0006]
The present invention has been made in view of the circumstances described above, and the object of the present invention is to provide a granular material that can quickly and efficiently dry the granular material while achieving energy saving. It is to provide a drying apparatus.
[0007]
[Means for Solving the Problems]
To achieve the above object, a first aspect of the present invention comprises a hot air dryer comprising a first drying chamber, and a vacuum dryer to a second drying chamber connected to the first drying chamber, the The second drying tank is provided with a heat retaining means for keeping the inside of the tank warm, the heat retaining means is a jacket, and the hot air dryer includes at least the first drying tank and the first drying tank. A drying line is connected to a blowing unit for blowing the drying medium and a heating unit for heating the drying medium blown by the blowing unit, and the drying line is provided in the jacket. A jacket supply line for blowing the drying medium is provided .
[0008]
According to such a configuration, the granular material is first supplied to the first drying tank of the hot air dryer, heated by the hot air and moisture immediately after the start of drying is removed, and then the second dryer of the vacuum dryer. It is supplied to a drying tank and dried under reduced pressure.
[0010]
Moreover, according to such a structure, since the inside of the tank of the 2nd drying tank which dries a granular material under reduced pressure is heat-retained, the granular material heat-dried in the 1st drying tank is 2nd drying. Even if it is supplied to the tank, it is dried under reduced pressure while maintaining the temperature.
[0012]
Moreover, according to such a structure, the inside of the tank of a 2nd drying tank can be heat-retained with a simple structure.
[0014]
Further, according to such a configuration, the drying medium is supplied into the jacket from the drying line of the hot air dryer through the jacket supply line.
[0015]
The invention according to claim 2 is the invention according to claim 1 , wherein the jacket supply line is branched from the downstream side of the heating means in the drying line, and is connected to the jacket on the inlet side. And an outlet side jacket line branched from the upstream side of the heating means in the drying line and connected to the jacket.
[0016]
According to such a configuration, the drying medium heated by the heating means of the hot air dryer branches off from the drying line, flows into the jacket from the inlet side jacket line, and then flows out of the jacket. It again joins the drying line and is heated again by the heating means.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an overall configuration diagram showing a processing system including an embodiment of a powder particle drying apparatus of the present invention.
[0018]
In FIG. 1, this processing system uses a drying device 1 to dry a granular material that has been transported by pneumatic transportation and transports it to other processing devices (for example, a molding machine, a mixer, etc.) 39a and 39b by pneumatic transportation. It is configured as a system.
[0019]
The drying apparatus 1 includes a hot air dryer 3 having a hot air drying hopper 2 as a first drying tank, and a vacuum dryer 5 having a reduced pressure drying hopper 4 as a second drying tank. The vacuum drying hopper 4 is connected to the connection pipe 29.
[0020]
The hot air dryer 3 includes a hot air drying hopper 2, a cyclone 6, a drying filter 7, a drying blower 8 as a blowing means, and a drying heater 9 as a heating means in the order of passage of air as a drying medium. By connecting through the blower pipes 11a, 11b, 11c, 11d, and 11e, a closed line that circulates hot air (that is, the drying heater 9 is connected to the hot air drying hopper 2 through the blower pipe 11e). A drying line 10 is configured.
[0021]
The hot-air drying hopper 2 includes a hot-air container portion 12 that receives powder particles, and a blower pipe 11 e connected to the heater 9 is connected so as to open in the hot-air container portion 12. Moreover, the hot-air container part 12 is formed so that the lower part is restrict | squeezed toward the bottom, and the discharge port 15 for discharging | emitting a granular material is formed in the lower end part. A connecting pipe 29 is connected to the discharge port 15, and an upper gate 16 for opening and closing the connecting pipe 29 is provided.
[0022]
Connected to the upper part of the hot air container section 12 are a transport pipe 20 connected to an ejector 19 for pneumatically transporting a granular material from a storage tank (not shown), and a blower pipe 11 a connected to the cyclone 6.
[0023]
The vacuum dryer 5 is sequentially provided with a line filter 23 and a vacuum pump 24 on the downstream side of the vacuum drying hopper 4, and these are connected via pressure reduction pipes 25a and 25b, respectively. It is configured. An air release valve 37 is provided in the middle of the decompression pipe 25 a that connects the decompression drying hopper 4 and the line filter 23, and the decompression that connects the line filter 23 and the decompression pump 24. The middle of the pipe 25b is formed in a fin shape to dissipate heat.
[0024]
The reduced-pressure drying hopper 4 includes a reduced-pressure container portion 27 that receives powder and a jacket 28 as heat retaining means for retaining the reduced-pressure container portion 27.
[0025]
The decompression vessel part 27 is connected to the upper part thereof with a connection pipe 29 connected to the hot air dryer 3 and a decompression pipe 25a connected to the line filter 23, and its lower part is squeezed downward. The discharge piping 30 for discharging a granular material is connected to the lower end part. The discharge pipe 30 is provided with a lower gate 31 for opening and closing the discharge pipe 30, and a relief valve 42 is provided in the middle thereof.
[0026]
The jacket 28 is formed at a predetermined interval from the outer wall surface of the depressurized container portion 27 so as to cover the outer peripheral side portion of the depressurized container portion 27, and a heat medium is supplied to the space spaced by the predetermined interval to keep the heat. Is configured to do. According to the jacket 28, the decompression container portion 27 can be kept warm with a simple configuration.
[0027]
In this drying apparatus 1, the drying line 10 of the hot air dryer 3 is provided with a jacket supply line 32 for sending hot air into the jacket 28, and the jacket 28 is heated from the drying line 10 through the jacket supply line 32. It is configured to supply a medium. That is, an inlet pipe 33 as an inlet side jacket line is branched off from the middle of the blower pipe 11e connecting the hot air drying hopper 2 and the dry heater 9 downstream of the drying heater 9 in the drying line 10. The inlet pipe 33 is connected to the jacket 28 from the side, and from the drying filter 7 disposed on the upstream side of the drying heater 9, an outlet pipe 34 as an outlet side jacket line different from the blower pipes 11b and 11c is provided. By branching and connecting the outlet pipe 34 to the jacket 28 from the side, a jacket supply line 32 is formed, a supply valve 35 is provided in the middle of the inlet pipe 34, and the supply valve 35 is opened and closed. The hot air can be sent into the jacket 28.
[0028]
In this drying apparatus 1, the hot air drying hopper 2, the vacuum drying hopper 4, the drying blower 8 and the drying heater 9 are covered with a heat insulating material 17.
[0029]
And in order to dry a granular material with the drying apparatus 1 comprised in this way, first, initial hot drying is performed in the hot air dryer 3. FIG. In order to perform initial heat drying by the hot air dryer 3, first, the upper gate 16 is closed and the drying blower 8 is operated. Then, air is sent from the drying blower 8 to the drying heater 9 through the blower pipe 11d, and hot air heated by the drying heater 9 is sent from the blower pipe 11e into the hot air container portion 12 of the hot air drying hopper 2. Then, it comes to flow out from the ventilation piping 11a.
[0030]
Next, by operating the ejector 19, the granular material is put into the hot air container section 12 from the transport pipe 20. Then, the granular material is dried such that moisture immediately after the start of drying is removed by the hot air sent into the hot air container portion 12.
[0031]
The hot air sent to the blower pipe 11a flows into the cyclone 6 connected to the blower pipe 11a to remove dust and the like, and then sent to the drying filter 7 through the blower pipe 11b to further dust. Etc. are removed, and then sent again to the drying blower 8 through the blower pipe 11c. Further, the hot air containing moisture in the hot air container 12 is released to the outside air by being partially released to the atmosphere by, for example, the cyclone 6 or the drying filter 7, and on the other hand, from the outside air It tries to prevent the increase of the humidity of the circulating hot air by taking in less air.
[0032]
Next, the granular material after the initial heat drying in the hot air dryer 3 is further sufficiently dried by the reduced pressure dryer 5.
[0033]
In order to perform drying by the reduced pressure dryer 5, first, when the drying blower 8 of the hot air dryer 3 is activated in advance, the supply valve 35 is opened, and the jacket 28 is passed through the inlet pipe 33 from the middle of the blower pipe 11e. Hot air is sent into the inside, and thereby the inside of the decompression container portion 27 is kept warm. The hot air flowing into the jacket 28 flows out to the drying filter 7 through the outlet pipe 34 and joins the drying line 10 again. Further, the opening / closing operation of the supply valve 35 may be performed continuously or intermittently as appropriate according to the heat insulation state in the decompression container portion 27.
[0034]
Next, the lower gate 31 is closed, the upper gate 16 is opened, the granular material is received in the decompression vessel portion 27, and then the upper gate 16 is closed again to operate the decompression pump 24. If it does so, the inside of the pressure reduction container part 27 will be pressure-reduced via pressure reduction piping 25a, 25b, and the granular material received in the pressure reduction container part 27 will be dried under reduced pressure. The capacity of the decompression pump 24 may be appropriately selected depending on the capacity of the decompression container 27, the type and size of the granular material, and for example, a capacity of about 40 to 100 Torr is used.
[0035]
The air sucked by the decompression pump 24 flows into the line filter 23 through the decompression pipe 25a, and after dust and the like are removed, the air is sent to the decompression pump 24 through the decompression pipe 25b.
[0036]
As described above, if the hot air dryer 3 is initially heated and dried, and then the vacuum dryer 5 is used to dry under reduced pressure, the moisture immediately after the start of drying is removed by the hot air in the initial heat drying. Then, since it is vacuum-dried by the vacuum dryer 5, the vacuum dryer 5 can be dried quickly and sufficiently under reduced pressure, and efficient drying that can save energy can be achieved. In addition, the apparatus can be reduced in size and simplified as compared with the use of a dehumidifying dryer, and more sufficient drying can be achieved. For example, when a dried powder is molded, a mold is used. As a result, it is possible to provide a granular material with good quality without causing stains due to poor drying.
[0037]
Moreover, in this drying apparatus 1, since the decompression container part 27 is kept warm by the jacket 28, the temperature of the granular material dried in the hot air dryer 3 is maintained even if it is supplied to the decompression container part 27. The dried product is dried under reduced pressure. Therefore, the granular material can be dried more quickly and sufficiently.
[0038]
Furthermore, in this drying apparatus 1, since hot air is supplied into the jacket 28 from the drying line 10 of the hot air dryer 3 via the jacket supply line 32, there is no need to supply a heat medium separately, Since there is no need for the equipment for the supply, the temperature can be efficiently kept with a simple configuration, and the cost of the apparatus and the running cost can be reduced. In particular, the jacket supply line 32 is formed by an inlet pipe 33 branched from the downstream side of the drying heater 9 and an outlet pipe 34 branched from the drying filter 7 on the upstream side of the drying heater 9. Since the hot air heated by 9 can be efficiently supplied to the jacket 28 and recovered, efficient heat retention can be achieved.
[0039]
Then, after sufficiently drying under reduced pressure by the reduced pressure dryer 5, the granular material in the reduced pressure container 27 is discharged by opening the air release valve 37 and opening the lower gate 31, and after the discharge is completed. The air release valve 37 and the lower gate 31 are closed to finish drying under reduced pressure. For example, transport pipes 38a and 38b connected to receivers 40a and 40b of other processing apparatuses 39a and 39b are connected to the discharge pipe 30, respectively, and the discharged granular materials are respectively transferred to the transport pipes 38a and 38b. Are ejected pneumatically to the receivers 40a and 40b via the transport pipes 38a and 38b.
[0040]
Further, the drying apparatus 1 is provided with an air supply unit 43 for compressing the air sucked by the decompression pump 24 and sending the compressed air to the transport system and the drive system.
[0041]
The air supply unit 43 includes a decompression pump 24 and a booster 44, a mist separator 45, and an air tank 46, which are sequentially arranged on the downstream side of the decompression pump 24, and these are pressurized pipes 47a, 47b, 47c, respectively. The pressurization line 48 is configured by being connected via the. A part of the pressurizing pipe 47a connecting the decompression pump 24 and the booster 44 is formed in a fin shape to dissipate heat, and a relief valve 49 is provided in the middle. Yes.
[0042]
The decompression pump 24 uses a swinging pump, and is configured to suck air from the decompression line 26 and simultaneously compress the air. The booster 44 further compresses the air compressed by the decompression pump 24. For example, the booster 44 further compresses the air compressed by the decompression pump 24 about twice. The mist separator 45 removes the mist condensed by the compression from the compressed air. The air tank 46 is filled with compressed air, and is connected to a compressed air supply pipe 52 connected to the electromagnetic valve 51. The electromagnetic valve 51 is configured to open and close corresponding to each of the ejectors 19, 41 a and 41 b, the upper gate 16 and the lower gate 31, and a pressure supply pipe for sending compressed air to each of them. 50a, 50b, 50c, 50d, and 50e are connected to each other. An air filter 53 is provided in the middle of the compressed air supply pipe 52.
[0043]
In such an air supply unit 43, the compressed air simultaneously sucked from the decompression line 26 by the decompression pump 24 is sent to the booster 44 through the pressurization pipe 47 a and further compressed, and then pressurized. After the dust sent to the mist separator 45 through the pipe 47b and condensed is removed, it is sent to the air tank 46 through the pressure pipe 47c and stored. When each of the ejectors 19, 41a and 41b, the upper gate 16 and the lower gate 31 is operated, the corresponding electromagnetic valve 51 is opened, so that the corresponding pressure supply pipes 50a, 50b, 50c, 50d and 50e are opened. Compressed air is sent through, thereby causing the ejectors 19, 41a and 41b, the upper gate 16 and the lower gate 31 to operate. The opening / closing operation of the upper gate 16 and the lower gate 31 is performed by driving air cylinders 54 and 55 to which compressed air is sent.
[0044]
By providing such an air supply unit 43, it is possible to operate the transport systems such as the ejectors 19, 41a and 41b and the drive systems such as the upper gate 16 and the lower gate 31 without providing a separate drive source. Therefore, it is possible to efficiently use the air sucked by the decompression pump 24, and it is possible to configure an efficient processing system that can save energy.
[0045]
In the embodiment described above, the inlet pipe 33 and the outlet pipe 34 of the jacket supply line 32 are connected to the upstream side and the downstream side of the drying heater 9, but hot air that can be kept warm can be supplied to the jacket 28. If it is a structure, you may branch from any position of the drying line 10 not only this .
[0046]
Moreover, the hot-air dryer 3 of this embodiment can be used in any known hot-air dryer as long as it is dried by hot air. Similarly, any known vacuum dryer can be used as long as the vacuum dryer 5 is in a vacuum state. In addition, in this invention, a reduced pressure dryer is synonymous with a vacuum dryer.
[0047]
Further, the type of the granular material is not limited, for example, resin pellets or ceramic particles.
[0048]
Further, the drying medium of the hot air dryer 3 can be appropriately selected depending on the purpose and application thereof, for example, nitrogen gas in addition to air.
[0049]
【The invention's effect】
As described above, according to the invention described in claim 1, since the granular material from which moisture has been removed in the hot air dryer is dried in the vacuum dryer, it can be dried quickly and sufficiently under reduced pressure, Efficient drying that can save energy can be achieved. In addition, since the apparatus can be reduced in size and simplified as compared with the use of a dehumidifying dryer, and more sufficient drying can be achieved, for example, when a dried granular material is molded, As a result, it is possible to provide a granular material with good quality without causing stains due to poor drying.
[0050]
Further , according to the invention described in claim 1 , since the granular material is dried under reduced pressure while maintaining the temperature heated in the first drying tank in the second drying tank, It can dry quickly and sufficiently.
[0051]
Moreover, according to invention of Claim 1 , the inside of the tank of a 2nd drying tank can be heat-retained by simple structure.
[0052]
Further, according to the first aspect of the present invention, since the drying medium is supplied into the jacket from the drying line of the hot air dryer through the jacket supply line, it is not necessary to supply the heating medium separately. Since there is no need for equipment for the supply, the temperature can be efficiently kept with a simple configuration, and the cost of the apparatus and the running cost can be reduced.
[0053]
According to the second aspect of the present invention, the jacket supply line is branched from the downstream side of the heating means in the drying line, and is connected to the upstream side of the heating means again through the jacket, so that it is heated. Since the drying medium can be efficiently supplied to the jacket and collected, efficient heat retention can be achieved.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram showing a processing system provided with an embodiment of a powder particle drying apparatus of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Drying apparatus 2 Hot-air drying hopper 3 Hot-air drying machine 4 Depressurization drying hopper 5 Decompression drying machine 8 Drying blower 9 Drying heater 10 Drying line 28 Jacket 32 Jacket supply line 33 Inlet piping 34 Outlet piping

Claims (2)

A hot air dryer comprising a first drying tank;
A vacuum dryer comprising a second drying tank connected to the first drying tank ;
The second drying tank is provided with a heat retaining means for retaining heat in the tank,
The heat retaining means is a jacket;
The hot air dryer includes at least the first drying tank, a blowing unit for blowing a drying medium to the first drying tank, and a heating unit for heating the drying medium blown by the blowing unit. Connected, equipped with drying line,
The said drying line is equipped with the jacket supply line for blowing a drying medium in the said jacket, The drying apparatus of the granular material characterized by the above-mentioned. The jacket supply line is branched from the downstream side of the heating means in the drying line and is branched from the upstream side of the heating means in the drying line and connected to the jacket. characterized in that it includes an outlet-side jacket line, granular material of the drying apparatus according to claim 1.

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