JP7132592B2 - Drying system and drying method - Google Patents

Description

The present invention relates to a drying system and drying method for drying powdery or granular material.

2. Description of the Related Art Conventionally, there has been known a drying system that dries a granular material supplied to a supply destination such as a molding machine on the upstream side of the supply destination. In such a drying system, a storage tank such as a material tank for storing the granular material, a hopper-like drying tank for storing and drying the granular material transported (replenished) from the storage tank, are known. In such a drying system, the powdery or granular material is dried by heated or dehumidified drying gas or the like in the drying tank. There was a concern that the moisture content of the
For example, Patent Document 1 below describes a first gas introduction unit that introduces an inert gas into a first storage tank that stores powder and a granular material that is transported from the first storage tank and is dried. and a second gas introduction part for introducing an inert gas into a discharge pipe provided at the lower end of the second storage tank.

JP 2015-30190 A

However, in the granular material processing apparatus described in Patent Document 1, it is necessary to provide a first gas introduction section and a second gas introduction section for introducing an inert gas into the first storage tank and the second storage tank, respectively. There is a need for further improvement.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a drying system and a drying method capable of suppressing moisture absorption of powdery or granular material in a storage tank disposed upstream of the drying tank. there is

In order to achieve the above object, the drying system according to the present invention comprises a storage tank for storing granular material, a drying tank for storing and drying the granular material transported from the storage tank, and an inert gas. A gas introduction unit for introducing an inert gas supplied from a supply unit into the drying tank, an exhaust port provided in the drying tank for discharging surplus gas, and a storage tank provided in the storage tank for introducing gas into the storage tank. and a gas pipeline connecting the gas receiving port to the storage tank, and the storage tank is provided with a leakage mechanism for leaking surplus gas while maintaining the inside of the storage tank at a positive pressure. and
Further, in order to achieve the above object, the drying system according to the present invention includes a storage tank for storing powdery or granular material, and a storage tank for storing powdery or granular material transported from the storage tank through a material transport pipeline. a drying tank for drying, a transport gas supply part for supplying inert gas supplied from an inert gas supply part as a transport gas to a discharge part of the storage tank connected to the material transport pipe line, and the drying tank and a gas pipeline connecting an exhaust port provided in the storage tank for discharging surplus gas and a gas inlet provided in the storage tank for introducing gas into the storage tank, wherein the storage tank includes: A leak mechanism is provided to leak surplus gas while maintaining a positive pressure in the storage tank .

Further, in order to achieve the above object, a drying method according to the present invention stores, in a drying tank, a powdery or granular material transported from a storage tank for storing the powdery or granular material, and while drying by introducing an inert gas into the drying tank, excess gas exhausted from the drying tank is sent through a gas pipe toward the storage tank and introduced into the storage tank. and a leakage mechanism provided in the storage tank to keep the inside of the storage tank at a positive pressure to cause leakage .
Further, in order to achieve the above object, the drying method according to the present invention supplies an inert gas as a transport gas to the discharge part of a storage tank for storing the powdery or granular material, and supplies the powder through the material transporting pipeline. While transporting the granular material toward the drying tank, excess gas exhausted from the drying tank is sent through a gas pipe to the storage tank and introduced into the storage tank, and stored. A leakage mechanism provided in the tank is characterized in that the inside of the reservoir is allowed to leak while maintaining a positive pressure .

The drying system and drying method according to the present invention are configured as described above, so that it is possible to suppress the moisture absorption of the granular material in the storage tank disposed upstream of the drying tank.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially broken schematic system diagram schematically showing an example of a drying system for a powdery or granular material according to an embodiment of the present invention, which is used in a drying method for a powdery or granular material according to an embodiment of the present invention. FIG. 2 is a schematic vertical cross-sectional view, partly cut away, schematically showing an example of a gas introduction section provided in the drying system. (a) is a partially broken schematic vertical cross-sectional view corresponding to the X section in FIG. 1, and (b) is a schematic time chart schematically showing an example of basic operations performed in the drying system.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.
In some figures, some of the reference numerals attached to other figures are omitted.
In addition, in FIGS. 1 and 2, a portion of a pipeline (piping), which is a route through which powdery material, gas, etc., is shown is schematically shown by a chain double-dashed line.
Also, the schematic time chart in FIG. 3B schematically shows detection, opening/closing, ON/OFF, etc. of each device.

1 to 3 are diagrams schematically showing an example of a drying system according to this embodiment and an example of a drying method performed using this drying system.
As shown in FIG. 1, the drying system 1 according to the present embodiment includes a storage tank 10 for storing the powdery or granular material, and the powdery or granular material transported from the storage tank 10 via the material transport pipeline 7. and a drying tank 30 for storing and drying. The drying system 1 also includes a gas introduction unit 40 for introducing the inert gas supplied from the inert gas supply unit 3 into the drying tank 30, an exhaust port 33 provided in the drying tank 10 for discharging surplus gas, and a reservoir. and a gas pipe line 8 that connects to a gas receiving port 19 (see FIG. 3A) provided in the tank 10 for introducing gas into the storage tank 10 .

With the above configuration, while the inert gas is introduced into the drying tank 30 to dry the stored granular material, the surplus gas discharged from the drying tank 30 is discharged through the gas pipeline 8. can be introduced into the storage tank 10 by supplying air toward the storage tank 10. As a result, compared to drying the powdery or granular material by introducing outside air into the drying tank 30, drying can be performed more efficiently, and the inside of the drying tank 30 becomes an inert gas atmosphere to dry the powdery or granular material. Oxidation can be suppressed. Moreover, the surplus gas used for drying the granular material can be introduced into the storage tank 10 serving as the supply source of the drying tank 30 . That is, the inert gas introduced into the drying tank 30 for drying the powdery material can also be introduced into the storage tank 10, and the inert gas is individually introduced into the drying tank 30 and the storage tank 10. The required amount of inert gas can be reduced compared to the one provided with the inlet. In addition, as a result, the inside of the storage tank 10 becomes an inert gas atmosphere and a positive pressure, so that the inflow of outside air into the storage tank 10 can be suppressed, and the granular material in the storage tank 10 can be suppressed. moisture absorption can be suppressed.
Further, in the present embodiment, the gas introduction section 40 is configured to heat the inert gas supplied from the inert gas supply section 3 and introduce it into the drying chamber 30 . That is, in the present embodiment, the gas introduction section 40 constitutes a heating gas introduction section. With such a configuration, the particulate material in the drying tank 30 can be efficiently dried by the heated inert gas. Moreover, since the surplus gas exhausted from the drying tank 30 has a higher temperature than the outside air, it is possible to preliminarily raise the temperature of the granular material in the storage tank 10 . Note that depending on the type of powdery material and the supply destination of the drying tank 30, the powdery material may be dried by introducing dehumidified inert gas into the drying tank 30 without heating. In this case, the gas introduction section 40 may be configured without the heating section 50 described later.

The drying system 1 also includes a transport gas supply unit 6 that supplies the inert gas supplied from the inert gas supply unit 3 to the discharge unit 28 of the storage tank 10 that communicates with the material transport pipeline 7 as a transport gas. I have it. In other words, in the present embodiment, the drying system 1 is configured to pneumatically transport the granular material from the storage tank 10 as a supply source to the drying tank 30 . With such a configuration, an inert gas is introduced as a transport gas into the discharge section 28 of the storage tank 10 for storing the powdery or granular material, and the powdery or granular material is transported through the material transporting pipeline 7 to the drying tank 30 . , the excess gas exhausted from the drying tank 30 can be sent through the gas pipe 8 toward the storage tank 10 and introduced into the storage tank 10 . This makes it possible to suppress moisture absorption of the granular material during transportation, compared to the case where outside air is used as the transportation gas. In addition, since the surplus gas used for transporting the powdery or granular material can be introduced into the storage tank 10 serving as the supply source of the drying tank 30, the powdery or granular material in the storage tank 10 can be discharged in the same manner as described above. Moisture absorption can be suppressed. In other words, the inert gas used for transporting the granular material can be introduced into the storage tank 10, and the material transport pipe line 7 and the storage tank 10 are each provided with an introduction part for introducing the inert gas. The amount of inert gas required can be reduced compared to the other. In other words, in the drying system 1, the inside of the storage tank 10 can be made into an inert gas atmosphere without providing an introduction part for directly introducing the inert gas into the storage tank 10. FIG.

The drying system 1 also includes a control panel 66 having a control section that controls each section and executes various modes to be described later. The control panel 66 includes a control unit including a CPU and the like, and a display unit and an operation unit for setting, inputting, and displaying various settings, which are connected to the control unit via signal lines and the like. , setting conditions and input values set and input by operating this display operation unit, various programs such as control programs for executing each operation described later, various preset operating conditions , and a storage unit that stores various data tables and the like and is configured from various memories and the like.

Here, the powdery or granular materials refer to materials in the form of powder or granules, but include materials in the form of microflakes, short fiber flakes, sliver-like materials, and the like.
Moreover, as the above material, any kind of material such as synthetic resin materials such as resin pellets and resin fiber pieces, metal materials, semiconductor materials, wood materials, chemical materials, and food materials may be used.
Examples of the powdery material include natural material (virgin material), pulverized material, masterbatch material, various additives, and the like in the case of molding a synthetic resin molded product. Moreover, it is good also as a structure containing reinforcing fibers, such as a glass fiber and a carbon fiber.

Further, the supply destination 2 of the drying tank 30 may be, for example, a molding machine such as an injection molding machine. This embodiment shows an example in which the drying tank 30 is directly installed on the molding machine as the supply destination 2 . The molding machine as the supply destination 2 is not limited to an injection molding machine for molding synthetic resin molded products, and may be an injection molding machine for other materials, an extrusion molding machine for various materials, a compression molding machine, or the like. Other molding machines may be used as supply destinations. Further, the supply destination 2 of the drying tank 30 is not limited to the molding machine, and may be a charge hopper, a compounding device, or the like on the molding machine. Moreover, the supply destination 2 of the drying tank 30 is not limited to a single supply destination, and may be a plurality of supply destinations.

In addition, the inert gas supplied from the inert gas supply unit 3 may be any gas having a low oxygen concentration, such as argon gas (argon-rich gas (argon-rich gas)), or nitrogen gas (nitrogen-rich gas). gas (nitrogen-rich gas) is preferred.
Examples of the inert gas supply unit 3 for generating such an inert gas include hollow fiber membrane separation type and pressure swing adsorption type (PSA type) gas generators. A PSA-type gas generator is preferable because it can efficiently obtain a high-concentration nitrogen gas. The inert gas supply unit 3 may be provided in the drying system 1 , or may be provided in a factory or the like separately from the drying system 1 and connected to the drying system 1 . The inert gas supplied from the inert gas supply unit 3 may be dehumidified gas or high pressure inert gas compressed to a relatively high pressure. Further, the inert gas supply unit 3 may be configured to selectively supply inert gas and compressed gas (compressor air).

In addition, the inert gas supply unit 3 includes a dry gas supply unit 5 that supplies inert gas to the gas introduction unit 40 via the downstream supply pipe line 4A, and a dry gas supply unit 5 that supplies inert gas to the discharge unit 28 of the storage tank 10 on the downstream side. It is connected through an upstream supply pipe line 4 to a transport gas supply unit 6 that supplies an inert gas through a pipe line 4B. The dry gas supply unit 5 and the transport gas supply unit 6 are provided with gas supply valves for switching between a state of supplying the inert gas and a state of blocking the supply of the inert gas. In addition, the dry gas supply unit 5 and the transport gas supply unit 6 are equipped with a regulator for adjusting pressure, a filter for capturing dust and the like, a micro mist separator (oil mist filter) for capturing oil mist and the like, and the like. A configuration in which a thermal refining unit is provided may be employed.

Further, the transport gas supply unit 6 is provided with a switching valve for switching between supply of compressed gas supplied from a compressed gas source such as a compressor and supply of inert gas from the inert gas supply unit 3 . In other words, in the present embodiment, an inert gas having a low oxygen concentration and a compressed gas having an oxygen concentration similar to that of the atmosphere can be selectively supplied to the discharge section 28 of the storage tank 10 as the transport gas. there is
Although the drawing shows an example in which the dry gas supply unit 5 is spaced apart from the drying tank 30 , it may be attached to the drying tank 30 or the storage tank 10 . In addition, although the figure shows an example in which the transport gas supply unit 6 is attached to the frame-shaped base 29 that holds the storage tank 10 , it is provided separately from the storage tank 10 and the base 29 . Alternatively, it may be attached to the drying tank 30 . Further, in the figure, an example is shown in which the upstream supply pipe line 4 connected to the inert gas supply unit 3 is branched and connected to the dry gas supply unit 5 and the transport gas supply unit 6. It is not limited to modes.

The drying tank 30 includes a collection section 31 that collects the powdery or granular material that is pneumatically transported through the material transportation pipeline 7, and a drying body 35 that is provided below the collection section 31. ing.
The collecting part 31 has a cylindrical shape that communicates with the inside of the drying body 35 . The collection unit 31 includes an inlet 32 communicating with the material transport pipe line 7, a separation unit 34 for separating the powdery or granular material from the transport gas, and a transport gas separated in the separation unit 34 for exhausting. An exhaust port 33 is provided.
The separation unit 34 may be of any type as long as it can separate the granule material and the transport gas. It may be made of a punching metal or a net-like (mesh-like) perforated plate-like body or the like.

The inlet 32 is provided on the top surface of the collecting section 31 so as to open downward. Separation part 34 is arranged so that a gap is formed between it and the inner peripheral surface of collection part 31 , and is cylindrical so as to surround inlet 32 . The exhaust port 33 is opened in the side peripheral wall of the collection section 31 on the outer peripheral side of the separation section 34 . In this embodiment, the exhaust port 33 constitutes the exhaust port 33 for exhausting excess gas from the drying tank 30 . That is, the gas pipe line 8 is connected to the exhaust port 33 so as to communicate therewith.
The granular material collected by the collection unit 31 falls into the drying body 35 due to its own weight and is stored therein. Note that the collection unit 31 is not limited to the configuration described above. For example, it is assumed that the input port 32 is provided so as to open at the side peripheral wall of the collection unit 31, the separation unit 34 is provided along the top surface, and the exhaust port 33 is opened at the top surface. good too. Alternatively, a structure may be adopted in which the particulate material is separated from the transport gas by a so-called cyclone system without providing the separating section 34 as described above.

The drying main body 35 includes a hopper portion 37 and a lid body 36 that covers an upper opening of the hopper portion 37 so as to be openable and closable. Further, the drying body 35 is provided with a material sensor 67 (see FIG. 3(b)) that outputs a material request signal (no material). Such a material sensor 67 may be, for example, a contact type sensor having a limit switch or the like that is turned ON/OFF by an arm portion that swings as the storage level of the granular material decreases. A non-contact type such as a type may also be used.

The lid body 36 is tightened to the hopper portion 37 by fasteners such as fasteners. The collecting part 31 described above is installed on the lid 36 . The lid 36 is provided with an opening that allows the lower end opening of the collecting section 31 and the hopper section 37 to communicate with each other.
The hopper portion 37 has a hopper shape in which an inverted frustum portion is provided on the lower end side of the cylindrical portion. The drawing shows an example in which the hopper portion 37 is elongated in the vertical direction. The hopper portion 37 may have a relatively small diameter (for example, an inner diameter of 200 mm or less) and a small capacity. For example, the drying system 1 may dry and supply optical resin pellets as a granular material to a supply destination 2 for molding an optical element such as a lens.

Further, the hopper portion 37 is provided with an introduction port 60a for introducing heated gas heated in a gas introduction portion 40 described later, and a return port 38 for returning part of the gas toward the gas introduction portion 40. there is The return port 38 is provided so as to open at the side peripheral wall of the upper end portion of the hopper portion 37 . The return port 38 is an upstream opening of a return pipe 42 connected to the gas introduction portion 40 .
The introduction port 60 a is provided so as to open at the lower end side portion of the hopper portion 37 . In this embodiment, the introduction port 60a is opened at the lower end of a gas introduction pipe 60 installed to extend vertically in the hopper portion 37 . The lower end of the gas introduction pipe 60 is provided with a rectifying section that expands downward. In addition, above the rectifying portion, the gas introduction pipe 60 is in contact with the inner peripheral wall of the hopper portion 37 so that the axis of at least the lower end portion of the gas introduction pipe 60 coincides with the axis of the hopper portion 37 . A plurality of restricting pieces that restrict the lower end side of the gas introduction pipe 60 are provided so as to protrude radially.

Further, in this embodiment, the gas introduction pipe 60 is detachably attached to the hopper portion 37 . With such a configuration, even when the diameter of the hopper portion 37 is small as described above, cleaning of the inside of the hopper portion 37 can be improved by removing the gas introduction pipe 60 . The drawing shows an example in which a holding portion for hooking and holding the upper end portion of the gas introduction pipe 60 is provided on the inner peripheral wall of the upper end portion of the hopper portion 37 . A connection port 39 is provided on the inner peripheral wall of the upper end portion of the hopper portion 37 so as to open as a downstream opening of an introduction pipe 58 connected to a gas introduction portion 40 described later. The upper end portion of the gas introduction pipe 60 is bent toward the inner peripheral wall of the hopper portion 37 so that the opening of the upper end portion is connected to the connection port 39 . Also, an example in which a grip portion is provided at the upper end portion of the gas introduction pipe 60 is shown. The manner in which the gas introduction pipe 60 is detachable from the hopper portion 37 is not limited to the manner described above, and various modifications are possible. Alternatively, the gas introduction pipe 60 may be fixed to the hopper portion 37 in a non-detachable manner. Further, instead of the aspect in which such a gas introduction pipe 60 is provided, the drying gas (in this embodiment, A mode in which an introduction port 60a for introducing the heated gas into the hopper portion 37 may be opened.

In addition, the drawing shows an example in which an input pipe 64 is provided on the lower side (exhaust side) of the drying main body 35 via an on-off valve 63 that is manually opened and closed. Such an on-off valve 63 is held by a holding portion 62 provided on the lower end side of the drying body 35 so as to be slidable substantially perpendicularly to the axial direction of the input pipe 64 , and the discharge valve 63 is held at the lower end of the drying body 35 . A slide shutter provided with an opening that communicates the outlet and the injection tube 64 and a closing portion that blocks the discharge port and the injection tube 64 may be used. The holding portion 62 that slidably holds the on-off valve 63 may be provided with sealing members 22 and 23 (see FIG. 3A) similar to the holding portion 20 of the storage tank 10 described later. Further, in the illustrated example, an example in which a residual material removal pipe 65 is provided so as to protrude from the side peripheral wall of the introduction pipe 64 is shown.
Moreover, in the example of a figure, the example which provided the outer peripheral cylinder part 61 which covers so that the outer peripheral side of the hopper part 37 may be enclosed is shown. In other words, the drying main body 35 has a so-called double tube structure with the outer peripheral tube portion 61 and the hopper portion 37 . A suitable heat insulating material may be filled between the inner peripheral surface of the outer peripheral cylindrical portion 61 and the outer peripheral surface of the hopper portion 37, or a band heater may be provided. Further, in the example of the drawing, an example in which the control panel 66 is attached to the outer peripheral cylindrical portion 61 is shown. And it may be installed at a location spaced apart from the storage tank 10 .

As shown in FIG. 2, in this embodiment, the gas introduction unit 40 passes through the granular material layer in the drying tank 30 with the introduction of the inert gas supplied from the inert gas supply unit 3. A mixing section 45 is provided to take in a part of the gas so as to circulate, mix it with the introduced inert gas, and supply the mixture to the downstream side. With such a configuration, when the inert gas is introduced, part of the gas that has passed through the powder material layer in the drying tank 30 is taken in the mixing unit 45, and the introduced inert gas and the dry tank 30 can be fed. That is, by introducing the inert gas, it is possible to dry the granular material while circulating part of the gas in the drying tank 30 . As a result, the amount of inert gas required for drying can be reduced compared to, for example, exhausting the gas introduced into the drying tank 30 without circulating it. In addition, intrusion of outside air can be suppressed as compared with the one in which the gas in the drying chamber 30 is circulated by a blower or the like.

Further, in the present embodiment, the dust collection section 41 is provided upstream of the mixing section 45 . The illustrated example shows an example in which the dust collecting section 41 is provided above the mixing section 45 .
The dust collecting section 41 is configured such that a filter section 44 is provided in a cylindrical body 43 whose side peripheral wall is connected to a return pipe 42 connected to the upper end portion of the hopper section 37 . The filter part 44 has a tubular shape coaxially provided with a gap between it and the inner peripheral surface of the tubular body 43 . A metal filter may be used as the filter portion 44 . With such a configuration, it is possible to easily wash using a solvent or the like. As such a metal filter, for example, a cylindrical filter obtained by sintering and integrating a plurality of layers of mesh, and a cylindrical filter obtained by sintering metal powder can be used. Moreover, this filter part 44 is provided detachably with respect to the cylindrical body 43 . In the illustrated example, the cylindrical body 43 is provided with an upper opening through which the filter portion 44 can be inserted and removed, and a cover is provided to cover the upper opening so as to be openable and closable.
Further, an opening opening toward the mixing section 45 is provided on the inner peripheral side of the filter section 44 on the bottom side of the cylindrical body 43 .

The mixing section 45 includes a tubular body 46 provided with an opening on the top side that is aligned with the opening of the tubular body 43 of the dust collecting section 41 . The cylindrical body 46 is provided with a connection portion 48 to which the downstream supply pipe line 4A connected to the dry gas supply portion 5 is connected. Further, a mixing nozzle 47 formed in a cylindrical shape is provided in the cylindrical body 46 so as to be communicated with the connecting portion 48 . The mixing nozzle 47 is provided with a gas passage 47a whose upstream opening communicates with the connecting portion 48 and whose downstream opening opens toward a connecting pipe 49 connected to a heating portion 50, which will be described later. A narrowed portion 47b having a small diameter is provided in the middle of the gas passage 47a. In addition, the mixing nozzle 47 is provided with an intake passage that communicates a plurality of gas intake ports 47c that are open on the outer peripheral side with the constricted portion 47b.

In the mixing section 45 configured as described above, when a high-pressure inert gas is introduced from the dry gas supply section 5 into the gas passage 47a, the flow rate increases in the constricted section 47b, resulting in a decrease in pressure (negative pressure action) at that site. As a result, the gas around the outer periphery of the mixing nozzle 47 (that is, the gas inside the cylindrical body 46) is taken into the gas passage 47a through the gas intake port 47c, and together with the introduced inert gas, flows through the connecting pipe from the downstream opening. 49 is discharged. In other words, the mixing section 45 is configured to take in the gas in the cylindrical body 46 by the so-called venturi action in the narrowed section 47b accompanying the introduction of the high-pressure inert gas, and discharge it toward the downstream side. A portion of the surplus gas in the drying body 35 is taken into the mixing section 45 through the return pipe 42 and the dust collection section 41 by such a venturi action, and is mixed with the inert gas. In addition, the inert gas introduced into the mixing nozzle 47 via the dry gas supply unit 5 and the gas discharged from the downstream opening of the mixing nozzle 47 (that is, the inert gas and the gas returned from the drying main body 35 are The flow ratio (volumetric flow ratio) between the added gas) and the gas may be about 1:1.5 to 1:5, preferably about 1:2 to 1:4.

Further, in this embodiment, the gas introduction section 40 includes a heating section 50 that heats the gas mixed in the mixing section 45 .
The heating section 50 has a main body case 51 into which the gas from the mixing section 45 is introduced. The main body case 51 has a cylindrical shape elongated in one direction (vertical direction in the figure), and a connection pipe 49 and an introduction pipe 58 are connected to one end in the longitudinal direction. The connecting pipe 49 is connected so as to pass through the side peripheral wall of the main body case 51 , and a downstream opening that opens in the main body case 51 constitutes a gas introduction port 52 for introducing gas into the main body case 51 .
In addition, the main body case 51 has an inner cylinder 55 elongated in one direction that is the same as the longitudinal direction of the main body case 51 and a linear heater 57 wound along the outer peripheral surface of the inner cylinder 55 . , and an outer cylinder 56 containing an inner cylinder 55 around which the linear heater 57 is wound. An opening at one end in the longitudinal direction of the inner cylinder 55 communicates with a gas outlet port 53 provided at one end in the longitudinal direction of the main body case 51 . In addition, the opening at the other longitudinal end of the inner cylinder 55 opens at the other longitudinal end inside the main body case 51 . Further, the gas introduction port 52 described above is open in the space on the outer peripheral side of the outer cylinder 56 .

With the configuration as described above, the linear heater 57 is arranged in the ring-shaped accommodation space formed between the outer peripheral surface of the inner cylinder 55 and the inner peripheral surface of the outer cylinder 56 . Since the gas passes through the inner peripheral side and the outer peripheral side of the outer cylinder 56 , foreign matter contained in the gas can be prevented from adhering or accumulating on the linear heater 57 . In addition, the gas introduced from the gas introduction port 52 provided at one end in the longitudinal direction of the main body case 51 and directed to the opening of the inner cylinder 55 that opens at the other end in the longitudinal direction is introduced into the outer space of the outer cylinder 56. can be preliminarily heated at Further, the preliminarily heated gas can be heated in the inner peripheral space of the inner cylinder 55 and discharged from the gas outlet 53 provided at one longitudinal end portion of the main body case 51 . That is, the gas introduced into the main body case 51 can be efficiently heated on the outer peripheral side of the outer cylinder 56 and the inner peripheral side of the inner cylinder 55 .

In this embodiment, the inner cylinder 55 and the outer cylinder 56 are shaped to penetrate in the longitudinal direction and have substantially the same length dimension. The inner cylinder 55, the outer cylinder 56, and the body case 51 are provided coaxially. Appropriate holding portions for holding the inner cylinder 55 and the outer cylinder 56 are provided at both ends of the body case 51 in the longitudinal direction.
In the present embodiment, the opening at one end in the longitudinal direction of the inner cylinder 55 is aligned with the gas outlet port 53 provided through the one end in the longitudinal direction of the main body case 51 in the longitudinal direction. Further, the longitudinal direction of the inner cylinder 55 is arranged at the other longitudinal end of the main body case 51 such that the opening of the inner cylinder 55 at the other longitudinal end of the inner cylinder 55 opens toward the inner surface of the other longitudinal end of the main body case 51 . It has the structure which provided the spacer part 54 interposed between the direction other end parts.

The linear heater 57 may be a so-called sheathed heater in which a heating wire such as a nichrome wire inserted in an elongated metal pipe is insulated from the metal pipe with powder such as magnesia. The linear heater 57 may have a spirally wound inner diameter (coil inner diameter) slightly smaller than the outer diameter of the inner cylinder 55 before being attached to the inner cylinder 55 . With such a configuration, the linear heater 57 can be brought into effective contact with the outer peripheral surface of the inner cylinder 55 . Further, if such a linear heater 57 is used as a heating source, the size of the heating source can be reduced, and by varying the length of the linear heater 57, the heater capacity can be varied. . The length of the linear heater 57 may be set appropriately according to the required heater capacity, and may be, for example, about 800 mm to 4000 mm. Moreover, although the example shown in the drawing shows an example in which the linear heater 57 is provided from the other longitudinal end of the inner cylinder 55 to an intermediate portion of the one longitudinal end of the inner cylinder 55 , the linear heater 57 is provided over substantially the entire longitudinal direction of the inner cylinder 55 . It is good also as a structure provided.

In addition, the diameter of the linear heater 57 (the outer diameter of the metal pipe) may be an appropriate diameter from the viewpoint of miniaturization of the heating unit 50, for example, about 2 mm to 10 mm. It may be 5 mm or less. The inner diameter of the outer cylinder 56 is set appropriately so that the linear heater 57 contacts or approaches the inner peripheral surface of the outer cylinder 56 when the inner cylinder 55 around which the linear heater 57 is wound is accommodated. It may be the diameter. Further, the thickness of the inner cylinder 55 and the outer cylinder 56 may be set appropriately from the viewpoint of strength, heat transfer, etc., and may be, for example, about 0.5 mm to 2 mm.
A holding portion for holding heater terminals of the linear heater 57 is provided at the other longitudinal end portion of the main body case 51 .
In addition, the inner cylinder 55 , the linear heater 57 and the outer cylinder 56 may be configured to be freely put in and taken out from the main body case 51 . With such a configuration, it is possible to improve cleanability and maintainability. Further, as indicated by a two-dot chain line in FIG.

A temperature sensor for detecting the temperature of the gas heated in the heating unit 50 is provided near the opening of one longitudinal end of the inner cylinder 55 on the exit side (see FIG. 1). The drawing shows an example in which the introduction pipe 58 is provided with a temperature sensor. Based on the temperature detected by the temperature sensor, the controller of the control panel 66 controls the energization of the heating element (linear heater 57) so that the heated gas reaches a predetermined temperature.
In the drying tank 30 configured as described above, when the gas supply valve of the dry gas supply unit 5 is opened and the linear heater 57 is activated (ON), the inert gas supply unit 3 Along with the introduction of the inert gas, part of the gas in the drying body 35 is taken in and mixed in the mixing section 45 via the return pipe 42 and the dust collection section 41, and sent toward the heating section 50. be. Then, it is heated in the heating unit 50 and supplied into the drying main body 35 . Surplus gas in the drying body 35 due to the introduction of the inert gas is exhausted from the exhaust port 33 and sent to the storage tank 10 through the gas pipe line 8 . In other words, in this embodiment, a part of the gas inside the drying body 35 is circulated by introducing the inert gas, and the remaining gas is exhausted through the exhaust port 33 . By introducing the inert gas into the drying body 35 and circulating a part of the gas while exhausting the surplus gas, the gas in the drying body 35 is substantially replaced with the inert gas. Further, the gas exhausted through the exhaust port 33 is also substantially inert gas.

The drying body 35 is substantially airtightly sealed except for the exhaust port 33 and the discharge port at the lower end, and the discharge port is connected to the molding machine serving as the supply destination 2 and substantially sealed. there is Further, leakage of gas from the gas pipeline 8 and the storage tank 10 downstream of the exhaust port 33 is regulated by leakage mechanisms 11 and 12, which will be described later. Therefore, the inside of the drying body 35 becomes a positive pressure (positive pressure) by introducing the inert gas.
The drying main body 35, the dust collecting section 41, the mixing section 45, and the heating section 50 of the drying tank 30 are not limited to the configurations described above, and may be configured appropriately. For example, a heater box that heats the drying body 35 while circulating the gas with a blower or the like may be provided, and an inert gas may be introduced to an appropriate location in the drying body 35. Other various modifications may be made. is possible.

The storage tank 10 as a supply source of the drying tank 30 includes, as shown in FIG. It has The storage tank 10 has a capacity larger than that of the drying body 35 described above. The capacity of the storage tank 10 may be three times or more, preferably five times or more, that of the drying body 35 .
In this embodiment, the storage tank 10 is held by a frame-shaped base 29 . The figure shows an example in which the base 29 is provided with rolling elements such as casters that can freely travel on the floor.
Further, in this embodiment, the storage tank 10 is provided with leakage mechanisms 11 and 12 for leaking surplus gas while maintaining the inside of the storage tank 10 at a positive pressure. With such a configuration, the inflow of outside air into the storage tank 10 can be suppressed more effectively than when the storage tank 10 is open to the atmosphere. moisture absorption can be suppressed.
Also, the leakage mechanisms 11 and 12 are provided at the upper end portion of the storage tank 10 . With such a configuration, nitrogen gas as an inert gas is lighter than oxygen and outside air. The inert gas can be effectively diffused by the

The reservoir main body 13 has a hopper shape that tapers downward toward the material discharge side. The shape of the storage main body 13 in a plan view may be a substantially square shape or a substantially circular shape. In the example shown, the storage body 13 has a stepped hopper shape in which the tubular portion, the inverted frustum-shaped portion, and the tubular portion and the inverted frustum-shaped portion are provided in this order from the upper side to the lower side. Although shown, it is not limited to such an embodiment.
The inlet 15 is provided at the upper end of the reservoir main body 13 so as to open upward. In addition, the upper end portion of the storage body 13 is provided with a lid mounting portion 14 that constitutes the opening peripheral portion of the inlet 15 . The lid mounting portion 14 is annularly provided over the entire circumference so as to protrude toward the inner diameter side (center side in plan view).

The lid 11 covering the input port 15 has a flat plate-shaped portion arranged on the upper side so as to cover the upper side of the storage main body 13, and the flat plate-shaped portion positioned on the outer peripheral side of the upper end portion of the storage main body 13. and a hanging part provided to hang down from the peripheral edge of the. In the present embodiment, the lid 11 is not configured to be fastened to the storage body 13 by fasteners such as fasteners, but is configured to be placed on the lid placement portion 14 of the storage body 13. It is That is, the lid body 11 is configured to close the inlet 15 of the storage main body 13 by its own weight. Also, the lid 11 is configured to be detachable from the storage main body 13 . The base 29 that holds the storage tank 10 may be provided with a holding portion capable of hooking and holding the detached lid 11 . Further, instead of such a mode, the lid 11 and the storage main body 13 may be connected by a suitable rotary connecting member such as a hinge.

Further, in the present embodiment, a seal member 12 is provided between the upper surface of the lid mounting portion 14 and the lower surface of the outer peripheral end portion of the flat plate portion of the lid 11 . The seal member 12 is annularly provided along the entire periphery of the opening of the inlet 15 . Also, the sealing member 12 may be made of a foamed resin material such as foamed silicon that is compressed and deformed by the weight of the lid 11, rubber, or the like. Also, the sealing member 12 may be attached to the lower surface of the flat plate portion of the lid 11 or may be attached to the upper surface of the lid mounting portion 14 .
In this embodiment, the lid 11 and the sealing member 12 that are closed by their own weight as described above function as a leakage mechanism. In other words, if gas is introduced through the gas pipeline 8 and the pressure in the storage tank 10 rises excessively, a part of the outer peripheral side end of the lid 11 rises against its own weight so as to float. A gap is formed between the sealing member 12 and the portion to be sealed (for example, the upper surface of the lid mounting portion 14) to allow the gas in the storage tank 10 to leak out. Further, even when such a gap is formed, gas is continuously introduced into the storage tank 10 via the gas pipe line 8, so that the dead weight of the lid 11 and the sealing member 12 affect other parts. The inside of the storage tank 10 is kept at a positive pressure by the seal of . Also, since the sealing member 12 is provided even when the introduction of gas is stopped, the inflow of outside air can be reduced.

In addition, the mass of the lid 11 and the sealing performance of the sealing member 12 may be adjusted so that the inside of the drying system 1 including the inside of the storage tank 10 has an appropriate pressure.
Moreover, the leakage mechanism provided in the storage tank 10 is not limited to the above-described modes. For example, as indicated by a two-dot chain line in FIG. Instead of 12B, an orifice or the like for leaking a small amount of gas may be provided. When such pressure regulating valves 12A and 12B and orifices are provided, the lid 11 is fastened to the reservoir main body 13 so that the lid 11 can hermetically seal the inlet 15 of the reservoir main body 13. It is good also as a structure which provided the suitable fastening mechanism which carries out. As the leakage mechanism provided in the storage tank 10, it is possible to employ those having various configurations. Further, instead of providing the storage tank 10 with the leakage mechanism, the gas pipeline 8, the material transport pipeline 7, the drying tank 30, etc. may be provided with the leakage mechanism. In other words, a leak mechanism for leaking surplus gas may be provided in at least one of the storage tank 10, the material transport pipeline 7, the drying tank 30, and the gas pipeline 8, which are connected in a substantially closed loop. Further, a pressure gauge for measuring the pressure inside the drying system 1 may be provided at an appropriate location, and when the pressure exceeds a preset monitoring pressure, a lamp or an alarm may be used to notify an abnormality.

The gas pipeline 8 is provided with a pipeline dust collector 9 . As the filter provided in the pipe dust collection section 9, a metal filter may be used as in the dust collection section 41 described above.
The end of this gas pipeline 8 is connected to a storage tank 10 . In this embodiment, as shown in FIG. 3(a), a gas receiving port 19 connected to the gas pipeline 8 is provided at the lower end portion of the storage tank 10. As shown in FIG. With such a configuration, the nitrogen gas as the inert gas introduced from the lower end portion of the storage tank 10 can be effectively diffused into the storage tank 10 .
Further, the gas receiving port 19 is provided so as to open below the inverted frustum-shaped portion of the lower end portion of the storage main body 13 . Further, in this embodiment, an outer cylinder 18 is provided to receive the discharge pipe 16 projecting downward from the lower end of the inverted frustum-shaped portion of the storage body 13 . is opened. With such a configuration, it is possible to prevent the gas inlet 19 from being clogged with the particulate material, and the gas introduced from the gas inlet 19 can be smoothly introduced into the storage tank 10 . be able to.

Further, the lower end surface 17 of the discharge pipe 16 is formed as an inclined surface in which the edge on the side farther from the gas inlet 19 than the edge on the gas inlet 19 side faces upward. The lower end of the peripheral wall of the discharge pipe 16 on the side of the gas inlet 19 is positioned below the gas inlet 19 , and the lower end of the peripheral wall on the side away from the gas inlet 19 is positioned above the gas inlet 19 . It is designed to With such a configuration, it is possible to suppress the intrusion of the particulate material into the gas inlet 19 side, and at the same time, it is possible to increase the opening area of the discharge pipe 16, so that the gas is introduced from the gas inlet 19. The gas can be introduced into the storage tank 10 more smoothly.
The gas receiving port 19 is not limited to the one configured as described above, and may be one having an opening in the inner peripheral surface of the discharge pipe 16 of the storage tank 10, an inverted frustum-shaped portion, a cylindrical portion, or the like. It's okay. Further, for example, the downstream portion of the gas pipe line 8 is accommodated in the storage tank 10, and the end opening thereof is used as the gas receiving port 19, and is opened in the middle of the vertical direction in the storage tank 10, or preferably at the lower end side portion. etc., and other various modifications are possible.

Further, in this embodiment, as shown in FIG. 3(a), an on-off valve 24 that is manually opened and closed is provided between the outer cylinder 18 and the lower end discharge pipe 27 communicating with the discharge portion 28. there is The on-off valve 24 is a slide shutter held by a holding portion 20 provided on the lower side of the outer cylinder 18 so as to be slidable substantially perpendicularly to the axial direction of the discharge pipe 16 . The holding portion 20 is provided with a slide recess 20 a that slidably receives the on-off valve 24 and an opening 21 that allows the discharge pipe 16 and the lower end discharge pipe 27 to communicate with each other. In the on-off valve 24, an opening 25 aligned with the opening 21 of the holding portion 20 and a closing portion 26 closing the opening 21 of the holding portion 20 are arranged side by side in the sliding direction.

Further, the holding portion 20 is provided with sealing members 22 and 23 along the vicinity of the periphery of the opening 21 . The seal members 22 and 23 are ring-shaped (annular) that are concentric with the opening 21. The seal ring 23 is in sliding contact with the upper surface of the on-off valve 24, and the seal ring 23 is oriented toward the on-off valve 24 side. and an elastic member 22 for urging.
The elastic member 22 and the seal ring 23 are accommodated in a ring-shaped accommodation groove 20b formed in the downward ceiling wall surface of the slide recess 20a of the holding portion 20 so as to surround the opening 21. As shown in FIG.
The elastic member 22 is made of an elastic material such as silicone rubber, and is shown in the drawing as a hollow ring having a substantially circular cross section. The elastic member 22 may be one that slightly biases the seal ring 23 toward the on-off valve 24 side, and is not limited to a hollow cylindrical member, and may be generally inverted V-shaped, In addition, various shapes may be used. Moreover, it is not limited to the one made of rubber or the like, and it may be made of a spring member such as a disc spring or a spring.

The seal ring 23 has a smooth and flat lower surface that contacts the upper surface of the on-off valve 24 in a sliding manner. The seal ring 23 is made of synthetic resin materials such as UHMWPE (ultra-high molecular weight polyethylene), Teflon (registered trademark), PEEK (polyetheretherketone), fluorine-based resins, and metal materials such as bronze and phosphor bronze. It may be made of a material having excellent abrasion resistance and slidability.
By providing the sealing members 22 and 23 as described above, the on-off valve 24 can be opened and closed relatively smoothly, and at the same time, the airtightness of the holding portion 20 that holds the on-off valve 24 in a slidable manner is improved. be able to.

The discharge part 28 of the storage tank 10 directs the granular material to the collection part 31 of the drying tank 30 through the material transport pipe line 7 by compressed gas or inert gas supplied through the transport gas supply part 6 . It is configured to be pumped. The discharge part 28 is substantially airtightly sealed by the valve body during non-transportation, and is supplied with compressed gas or inert gas during transport, so that the discharge part 28 is substantially substantially sealed from the outside air.
Although not shown in detail, the discharge section 28 is connected to three downstream supply pipelines 4B, 4B, 4B, which are respectively connected to the transport gas supply section 6. As shown in FIG. In the discharge portion 28, by switching and supplying high-pressure gas (compressed gas or inert gas) to each of these downstream supply pipes 4B, 4B, 4B, the valve body provided in the discharge portion 28 Opening and closing, transportation of the granular material that falls under its own weight to the discharge section 28 side, and purging (feeding off) of the granular material in the material conveying pipeline 7 after closing the valve body may be performed.

The particulate material transported to the drying tank 30 side through the material transport pipe line 7 together with the compressed gas or inert gas as the transport gas from the discharge part 28 is separated from the transport gas in the collection part 31 and captured. It is collected and thrown into the drying body 35 . Further, the transport gas separated in the collecting section 31 is exhausted from the exhaust port 33 and returned to the storage tank 10 through the gas pipeline 8 .
That is, in the present embodiment, the surplus gas out of the gas supplied to the drying tank 30 for drying and substantially the entire amount of the gas supplied for transportation are introduced into the storage tank 10 via the gas pipeline 8. be introduced. If a leakage mechanism is provided at a location other than the storage tank 10 as described above, part of the gas will leak from the leakage mechanism and the remaining gas will be introduced into the storage tank 10 .
Moreover, the discharge part 28 provided in the lower part of the storage tank 10 is not limited to the one described above, and other various structures may be used. For example, a configuration in which the discharge portion 28 is not provided with the valve body as described above may be employed. Even in such a system, the interior of the drying system 1 is substantially sealed except for the leakage mechanisms 11 and 12 described above and is kept at a positive pressure, so that outside air is difficult to enter.

In the drying system 1 configured as described above, the powdery or granular material transported from the storage tank 10 for storing the powdery or granular material is stored in the drying tank 30, and the stored powdery or granular material is While the heated inert gas is introduced into the drying tank 30 for drying, the surplus gas discharged from the drying tank 30 is sent through the gas pipe line 8 toward the storage tank 10 and into the storage tank 10. It is possible to implement a drying method to introduce.
In the drying system 1, an inert gas is introduced as a transport gas into the discharge section 28 of the storage tank 10 for storing the powdery material, and the powdery material is transported through the material transport pipe 7 to the drying tank. 30, the excess gas discharged from the drying tank 30 is sent through the gas pipeline 8 toward the storage tank 10 and introduced into the storage tank 10. ing.

Such a drying method is executed by controlling each device of the drying system 1 by the control section of the control panel 66 described above.
3B, when the drying system 1 is activated, the gas supply valve of the drying gas supply unit 5 is opened, the linear heater 57 is turned on, A heated gas is supplied into the drying body 35 of the . At this time, if no powdery material is stored in the drying main body 35, that is, if a material request signal is output from the material sensor 67 of the drying main body 35, the gas supply valve of the transportation gas supply unit 6 is turned off. is opened, high-pressure gas (compressed gas in the figure) is supplied to the discharge part 28 of the storage tank 10 as described above, and the granular material is transported to the drying body 35 . The transportation of the granular material to the drying main body 35 may be continued until a predetermined time has passed, or until a full signal is output from an upper limit level meter or the like provided in the drying main body 35. good too. Before the drying system 1 is activated, the lid 11 of the storage tank 10 may be opened and the granular material may be introduced and stored in the storage tank 10. .

In addition, when transporting as described above, the on-off valve 63 at the bottom of the drying tank 30 may be closed so that the undried granular material is not supplied toward the supply destination 2. .
Further, when the powdery or granular material is stored in the drying body 35, an initial drying mode for drying the powdery or granular material to a predetermined moisture content in the drying body 35 is executed. In addition, while the surplus gas, which is part of the gas used for drying, is introduced into the storage tank 10 as described above and leaked from the leakage mechanisms 11 and 12, the pressure in the system including the storage tank 10 is kept positive. is kept at
After the powdery or granular material in the drying body 35 is dried, the on-off valve 63 is opened as necessary to supply the powdery or granular material in the drying body 35 toward the supply destination 2 . In the molding machine serving as the supply destination 2, after random shots, trial shots, and the like are performed as appropriate, a steady operation mode for molding molded products is sequentially executed.

If the granular material is consumed at the supply destination 2 in this manner, the storage level of the granular material in the drying body 35 is lowered. Then, when a material request signal is output from the material sensor 67, the gas supply valve of the transport gas supply unit 6 is opened, and a high-pressure gas (inert gas) to transport the granular material to the drying body 35 . That is, in the present embodiment, compressed gas is used to transport the granular material in the initial transportation mode at the beginning of operation, and inert gas is used to transport the granular material in the transportation mode during steady operation. It is configured to Instead of such a mode, a configuration may be adopted in which the inert gas is used to transport the granular material even in the initial transport mode.
Also, the basic operation described above is merely an example, and various other operations can be performed.

Moreover, the configuration of each part of the drying system 1 is not limited to the above example, and various other modifications are possible. For example, in the present embodiment, the gas introduction unit 40 that introduces the inert gas supplied from the inert gas supply unit 3 into the drying tank 30 and the inert gas supplied from the inert gas supply unit 3 are used as materials. Although an example is shown in which the transport gas supply unit 6 that supplies the transport gas to the discharge unit 28 of the storage tank 10 that communicates with the transport pipe line 7 is provided, only one of them may be provided. For example, in place of the inert gas, a compressed gas or a dehumidified gas may be introduced into the drying chamber 30, or outside air may be heated and introduced. Alternatively, only a compressed gas can be introduced into the discharge section 28 as the transport gas, or instead of pumping, a suction blower is connected to the collection section 31 via a suction path to carry out suction transport. may be Further, instead of pneumatically transporting the powdery or granular material from the storage tank 10 to the drying tank 30, it is possible to supply the powdery or granular material by dropping it from the storage tank 10 toward the drying tank 30 by its own weight. It is good also as a mode etc.

REFERENCE SIGNS LIST 1 drying system 6 transportation gas supply unit 7 material transportation pipeline 8 gas pipeline 10 storage tank 11 lid (leakage mechanism)
12 sealing member (leakage mechanism)
12A, 12B pressure control valve (leakage mechanism)
18 Outer cylinder (lower end side part)
REFERENCE SIGNS LIST 19 Gas receiving port 28 Discharge part 30 Drying tank 33 Exhaust port 40 Gas introduction part 45 Mixing part 3 Inert gas supply part

Claims (7)

A storage tank for storing the granular material, a drying tank for storing and drying the granular material transported from the storage tank, and an inert gas supplied from an inert gas supply unit is introduced into the drying tank. and a gas pipeline connecting an exhaust port provided in the drying tank for discharging surplus gas and a gas receiving port provided in the storage tank for introducing gas into the storage tank. and
A drying system according to claim 1, wherein the storage tank is provided with a leakage mechanism for leaking surplus gas while maintaining the inside of the storage tank at a positive pressure . A storage tank for storing the granular material, a drying tank for storing and drying the granular material transported from the storage tank through the material transport pipeline, and an inert gas supplied from the inert gas supply part as a transport gas to the discharge part of the storage tank communicating with the material transport pipeline, an exhaust port provided in the drying tank for discharging surplus gas, and the storage tank provided with the a gas pipeline connecting to a gas receiving port for introducing gas into the storage tank ,
A drying system according to claim 1, wherein the storage tank is provided with a leakage mechanism for leaking surplus gas while maintaining the inside of the storage tank at a positive pressure . In claim 1,
Transportation in which an inert gas supplied from an inert gas supply unit is introduced as a transport gas into a discharge part of the storage tank that communicates with a material transport pipeline that transports the powdery or granular material from the storage tank to the drying tank. A drying system comprising a gas inlet. In any one of claims 1 to 3,
The gas introduction section for introducing gas into the drying tank is accompanied by the introduction of the inert gas supplied from the inert gas supply section, and part of the gas that has passed through the granular material layer in the drying tank is A drying system comprising a mixing section that takes in the inert gas so as to circulate it, mixes it with the introduced inert gas, and supplies it toward the downstream side. In any one of claims 1 to 4,
The drying system, wherein the gas receiving port is provided at a lower end portion of the storage tank. The powdery or granular material transported from the storage tank for storing the powdery or granular material is stored in the drying tank, and the stored powdery or granular material is dried by introducing an inert gas into the drying tank , Excess gas exhausted from the drying tank is sent through a gas pipe toward the storage tank and introduced into the storage tank. A drying method characterized by leaking while maintaining a positive pressure . An inert gas is supplied as a transport gas to the discharge part of a storage tank that stores the powdery or granular material, and the powdery or granular material is transported toward the drying tank through the material transport pipeline while being exhausted from the drying tank. The surplus gas is fed into the storage tank through the gas pipeline and introduced into the storage tank, and the inside of the storage tank is maintained at a positive pressure by a leakage mechanism provided in the storage tank. A drying method characterized in that it is leaked .

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