JP5737928B2 - Method for producing dry granule - Google Patents

Description

  The present invention relates to a method for producing a dry granular material.

  2. Description of the Related Art Conventionally, as a drying device for drying powder particles such as resin pellets, a hot air dryer that heats and drys the powder particles with hot air is known.

  In such a hot-air dryer, the granular material may block in the dryer. Therefore, methods for preventing blocking have been studied.

  For example, a stirring means and an air purge device are provided in a hopper in which pellets are stored, and the pellets adhering to the side wall of the hopper are stirred by the stirring blades, and the air purge device tries to adhere to the lower portion of the hopper. There has been proposed a hopper device capable of preventing pellet blocking in the hopper by stirring the pellets (see, for example, Patent Document 1 below).

JP 2006-143263 A

  However, in the hopper device described in Patent Document 1 described above, it is necessary to provide a stirring means and an air purge device in the hopper, which complicates the configuration of the hopper.

  Therefore, an object of the present invention is to provide a method for producing a dry granular material that can efficiently dry the granular material while suppressing blocking of the granular material in the dry hopper with a simple configuration. There is to do.

In order to achieve the above-described object, the invention described in claim 1 includes an input port into which a granular material made of a resin material is input, and an output port from which the granular material dried from the granular material is discharged. Using a drying apparatus having a drying hopper having a dry hopper, and drying the granular material before being supplied to a supply device that consumes the granular material, wherein the discharge port is A low-temperature drying step of closing the powder particles in the drying hopper at a first temperature while closing and restricting the discharge of the particles from the drying hopper, and opening the discharge port for the drying When the powder particles are discharged from the hopper and the powder particles discharged from the discharge port are supplied to the supply device, the powder particles in the drying hopper are switched from the low temperature drying step. , High temperature drying at a second temperature higher than the first temperature And a degree, the first temperature and the second temperature is characterized that it is set to a temperature lower than the Vicat softening temperature of the powder or granular material (JIS K 7206, B50 method).

  According to such a method, in the low-temperature drying step, the granular material in the drying hopper is dried at a low temperature while regulating discharge of the granular material from the drying hopper.

  Thereby, when the powder is not discharged from the dry hopper and the flow of the powder is small, the powder in the dry hopper can be dried at a low temperature, and the powder is blocked in the dry hopper. This can be suppressed.

  Moreover, when discharging a granular material from a drying hopper, it switches to a high temperature drying process, and dries the granular material in a drying hopper at high temperature.

  Thereby, when the powder is discharged from the drying hopper and the powder is flowing, the powder in the drying hopper can be dried at a high temperature, and the powder can be efficiently dried. .

  Therefore, it is possible to efficiently dry the granular material while suppressing blocking of the granular material in the drying hopper.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, the low-temperature drying step and the high-temperature drying step are alternately repeated.

  According to such a method, in the dry hopper, the dried granular material can be discharged | emitted intermittently, suppressing that a granular material blocks.

The invention of claim 3 is the invention according to claim 1 or 2, wherein the drying device, from the previous SL-receiving device is capable of receiving a request signal for requesting the powder or granular material, The drying apparatus is switched to the high temperature drying process by receiving the request signal, and the drying apparatus is switched to the low temperature drying process by not receiving the request signal for a predetermined time.

  According to such a method, a granular material can be dried, supplying the dried granular material to a to-be-supplied apparatus.

  According to the first aspect of the present invention, the granular material can be efficiently dried while suppressing blocking of the granular material in the dry hopper.

  Moreover, according to invention of Claim 2, the dried granular material can be discharged | emitted intermittently, suppressing that a granular material blocks in a dry hopper.

  Moreover, according to invention of Claim 3, a granular material can be dried, supplying the dried granular material to a to-be-supplied apparatus.

It is a schematic block diagram which shows the drying system used for the manufacturing method of the dry granular material of this invention. It is a flowchart which shows the drying process of a granular material. It is a flowchart which shows a low-temperature drying process. It is a flowchart which shows a high temperature drying process.

  FIG. 1 is a schematic configuration diagram showing a drying apparatus used in the method for producing a dry granular material of the present invention.

  As shown in FIG. 1, the drying apparatus 1 is provided with powder particles supplied from a tank (not shown) in which powder particles made of a resin material (for example, a resin material having thermoplasticity such as acrylic resin) are stored. The apparatus is configured as an apparatus for drying a body to produce a dry powder and supplying the obtained dry powder to a molding machine 2 (an example of an apparatus to be supplied).

  The drying apparatus 1 includes a drying hopper 3, an aerodynamic transport section 4 that pneumatically transports the granular material from a tank (not shown) to the drying hopper 3, a hot air supply section 5 that supplies hot air to the drying hopper 3, and a drying apparatus. And a control unit 6 for controlling the operation of 1.

  The drying hopper 3 includes a storage tank 11 and a slide gate 12.

  The storage tank 11 is formed so that the substantially cylindrical upper portion and the substantially conical lower portion whose opening cross-sectional area decreases downward are continuous. Moreover, the upper end part of the storage tank 11 is provided with the lid | cover which coat | covers the storage tank 11 from upper direction, and the inlet 31 into which a granular material is thrown into the lid | cover is provided. In addition, a discharge port 32 for discharging the dry granular material from the storage tank 11 is provided at the lower end of the storage tank 11. A discharge pipe 33 is connected to the discharge port 32 via the slide gate 12.

  The slide gate 12 is connected to the lower end of the storage tank 11 so as to open and close the discharge port 32. The slide gate 12 is slidably provided in an open position where the discharge port 32 is opened and a closed position where the discharge port 32 is closed.

  The pneumatic transportation unit 4 includes a loader hopper 13, a transportation line 14, a suction line 15, and a transportation blower 16.

  The loader hopper 13 is a hopper that is smaller than the drying hopper 3, and is formed such that a substantially cylindrical upper portion and a substantially conical lower portion whose opening cross-sectional area decreases downward are continuous. . The loader hopper 13 is connected to the lid of the drying hopper 3 at the lower end so as to communicate with the charging port 31 of the drying hopper 3.

  The transport line 14 is a pipe that transports the granular material from a tank (not shown) to the loader hopper 13, and its upstream end in the transport direction is connected to the tank (not shown) and is downstream in the transport direction. The side end is connected to the side wall of the loader hopper 13.

  The suction line 15 is a pipe that exhausts from the loader hopper 13 to the transport blower 16, and its exhaust direction upstream end is connected to the upper wall of the loader hopper 13, and its exhaust direction downstream end is the transport blower 16. It is connected to the. The upstream end of the suction line 15 in the exhaust direction is surrounded by the punching metal plate 10 and the like on the inner side of the upper wall of the loader hopper 13.

  The transport blower 16 sucks the transport line 14, the loader hopper 13, and the suction line 15, and generates an air flow from a tank (not shown) toward the transport blower 16.

  Then, the granular material in the tank (not shown) is transported to the loader hopper 13 via the transport line 14 by the air flow generated by the transport blower 16. Thereafter, when the transport blower 16 is stopped and a discharge valve (not shown) provided at the lower end of the loader hopper 13 is opened, the powder particles are discharged from the loader hopper 13 to the drying hopper 3.

  In the loader hopper 13, there is also an airflow that passes through the punching metal plate 10 and is sucked into the suction line 15 and toward the transport blower 16. 10 restricts suction to the suction line 15.

  The hot air supply unit 5 includes a hot air supply line 17, a drying blower 18, an intake line 19, and a circulation line 20.

  The hot air supply line 17 is a pipe that heats the airflow from the drying blower 18 and supplies the airflow to the drying hopper 3, and its supply direction upstream end is connected to the drying blower 18, and its supply direction downstream end The part passes through the side wall of the drying blower 18 and is disposed in the drying hopper 3. In the middle of the hot air supply line 17, a heater 21 for heating the airflow from the drying blower 18 is provided outside the drying hopper 3. A nozzle 22 for blowing hot air into the drying hopper 3 is provided at the downstream end of the hot air supply line 17 in the supply direction.

  The drying blower 18 blows air into the hot air supply line 17 while sucking the inside of the intake line 19, and generates an air flow from the intake line 19 through the drying blower 18 into the drying hopper 3. The drying blower 18 is provided with an inverter (not shown). And the drying blower 18 can change the ventilation volume by carrying out inverter control based on the signal from CPU25 (after-mentioned).

  The intake line 19 is a pipe that sucks outside air into the drying blower 18, the intake direction upstream end thereof is open to the atmosphere, and the supply direction downstream end thereof is connected to the drying blower 18. A filter 23 that collects dust and the like is provided in the middle of the intake line 19.

  The circulation line 20 is a pipe that exhausts the air in the drying hopper 3 to the intake line 19, the exhaust direction upstream end thereof is connected to the drying hopper 3, and the exhaust direction downstream end thereof is the switching valve 24. To the upstream end of the intake line 19 in the intake direction (specifically, the upstream end of the intake line 19 in the intake direction upstream of the filter 23). The switching valve 24 cuts off the communication between the intake line 19 and the circulation line 20, opens the intake line 19 to the atmosphere, connects the intake line 19 to the circulation line 20, and connects the intake line 19 to the atmosphere. It is switched to the circulation side that closes the atmosphere.

  When the switching valve 24 is switched to the circulation side and the drying blower 18 is operated, the airflow generated by the drying blower 18 is first heated by the heater 21 and then blown into the drying hopper 3 from the nozzle 22. Next, the hot air (heated airflow) blown into the drying hopper 3 heats and drys the powder in the drying hopper 3 and then returns to the intake line 19 via the circulation line 20 to be filtered. Then, the air is sucked into the dry blower 18 again.

  It should be noted that the outside air can be taken into the intake line 19 by switching the switching valve 24 to the atmosphere opening side as appropriate.

  The control unit 6 includes a receiving device 26 and a CPU 25.

  The receiving device 26 is configured to be able to receive a detection signal (described later) or a non-detection signal (described later) from a level sensor 44 (described later) by a known wireless or wired communication method.

  The CPU 25 is electrically connected to the slide gate 12, the transport blower 16, the drying blower 18, and the receiving device 26. The CPU 25 receives a detection signal (described later) or a non-detection signal (described later) from the level sensor 44 (described later) via the receiving device 26, and the operations of the slide gate 12 and the drying blower 18 based on these signals. To control.

  The drying apparatus 1 and the molding machine 2 are connected via a supply line 41.

  The supply line 41 is a pipe that supplies dry powder and granules from the dry hopper 3 to the molding machine 2, and its upstream end in the supply direction is connected to the discharge pipe 33 of the dry hopper 3, and downstream in the supply direction. The side end portion is connected to the molding machine 2. A level detector 42 is provided in the vicinity of the molding machine 2 in the middle of the supply line 41.

  The level detection unit 42 stores the dry powder particles that are in the middle of being supplied to the molding machine 2, and whether or not the dry powder particles retained in the retention unit 43 are at a certain level. And a known level sensor 44.

  The level sensor 44 transmits to the CPU 25 a detection signal indicating the detection of the dry powder or a non-detection signal (an example of a request signal) indicating the non-detection of the dry powder and particles to the CPU 25 at regular intervals.

  FIG. 2 is a flow diagram showing a drying process of the granular material. FIG. 3 is a flowchart showing a low-temperature drying process. FIG. 4 is a flowchart showing the high-temperature drying process.

  Hereinafter, the drying process of a granular material is demonstrated, referring FIGS.

  In one embodiment of the method for producing a dry granular material of the present invention, after the granular material is stored in the dry hopper 3, as shown in FIG. 2, when drying is started, first, a low temperature drying process (S1) is performed. To be implemented. When the drying is started, the slide gate 12 is disposed at the closed position, and the discharge of the powder particles from the drying hopper 3 is restricted.

  In the low temperature drying process (S1), as shown in FIG. 3, the hot air is supplied from the hot air supply unit 5 to the drying hopper 3 (S11).

  In the low temperature blowing (S11), the CPU 25 controls the blowing amount of the drying blower 18 so that the temperature in the drying hopper 3 is the recommended preliminary drying temperature of the granular material (the preliminary drying temperature before molding, The temperature is adjusted to a first temperature that is 10 to 20 ° C. lower than the upper limit of the temperature recommended by the body manufacturer. Specifically, when the recommended preliminary drying temperature is 90 ° C, the temperature is adjusted to 70 to 80 ° C.

  In addition, 1st temperature can also be adjusted to 30-40 degreeC lower temperature with respect to the Vicat softening temperature (JISK7206, B50 method) of a granular material, for example.

  In the low temperature drying treatment (S1), the first temperature is blown at a low temperature (S11) for several hours (for example, 2 to 3 hours) longer than the drying time recommended by the powder and particle maker, and the particles (Specifically, this S11 corresponds to a low-temperature drying step).

  Next, the granular material is supplied from the drying hopper 3 to the molding machine 2. When the granular material is transported from the drying hopper 3 to the molding machine 2 for the first time, the level sensor 44 transmits a non-detection signal to the CPS 25 because there is no granular material in the staying portion 43 of the level detecting unit 42 ( S12: NO).

  When receiving the non-detection signal, the CPU 25 controls the operation of the slide gate 12 to move the slide gate 12 to the open position.

  Thereby, the transport from the drying hopper 3 to the molding machine 2 is started (S13), and the granular material is supplied from the drying hopper 3 to the molding machine 2 through the supply line 41.

  Next, when the powder is filled in the molding machine 2 and stays in the supply line 41 until it is detected by the level sensor 44 in the stay part 43, a detection signal is transmitted from the level sensor 44 to the CPU 25. (S14: YES), CPU25 which received the detection signal controls the operation | movement of the slide gate 12, and moves the slide gate 12 to a closed position.

  Thereby, the transport of the dry granular material from the dry hopper 3 to the molding machine 2 is stopped (S15).

  Next, the CPU 25 automatically switches the low-temperature drying process (S1) to the high-temperature drying process (S2) by controlling the drying blower 18 so that the air blowing amount increases (S16).

  That is, when the slide gate 12 is disposed at the open position and the granular material is discharged from the drying hopper 3, the low temperature drying process (S1) is switched to the high temperature drying process (S2).

  In the high temperature drying process (S2), as shown in FIG. 4, the hot air is supplied from the hot air supply unit 5 to the drying hopper 3 (S21).

  In the high temperature air blowing (S21), the temperature in the drying hopper 3 corresponds to the upper limit value of the recommended preliminary drying temperature of the granular material (the preliminary drying temperature before molding, which is recommended by the manufacturer of the granular material). The second temperature is adjusted. Specifically, when the recommended preliminary drying temperature is 90 ° C, the temperature is adjusted to 85 to 90 ° C.

  In addition, the 2nd temperature in a high temperature drying process (S2) can also be adjusted to a temperature lower by 10-20 degreeC with respect to the Vicat softening temperature (JISK7206, B50 method) of a granular material, for example.

  Thereby, in a high temperature drying process (S2), a granular material is dried at 2nd temperature higher than 1st temperature (specifically, S21-S27 correspond to a high temperature drying process).

  Next, when the granular material supplied to the molding machine 2 is melted, molded, and consumed, the granular material retained in the retention portion 43 of the level detection unit 42 is reduced, and the upper end portion of the granular material is , The level sensor 44 is not detected.

  Then, a non-detection signal is transmitted from the level sensor 44 to the CPU 25 (S22: NO), and the CPU 25 that has received the non-detection signal controls the operation of the slide gate 12 to move the slide gate 12 to the open position.

  Thereby, transport of the granular material from the drying hopper 3 to the molding machine 2 is started (S23), and the granular material is supplied from the drying hopper 3 to the molding machine 2 through the supply line 41.

  Next, if the particulate matter is retained in the supply line 41 until it is detected by the level sensor 44 in the retention portion 43, a detection signal is transmitted from the level sensor 44 to the CPU 25 (S24: YES), and the detection signal is detected. The CPU 25 that has received the control controls the operation of the slide gate 12 to move the slide gate 12 to the closed position.

  Thereby, transportation of the granular material from the drying hopper 3 to the molding machine 2 is stopped (S25).

  After that, when the granular material supplied to the molding machine 2 is consumed again, if the granular material retained in the retention unit 43 of the level detection unit 42 decreases, based on the non-detection signal from the level sensor 44. Then, the granular material is transported from the dry hopper 3 to the molding machine 2 (S22 to S25).

  On the other hand, when the granule supplied to the molding machine 2 is not consumed, such as when the molding machine 2 is stopped, the granular material retained in the retention unit 43 of the level detection unit 42 does not decrease. The upper end portion of the granular material continues to be detected by the level sensor 44.

  In this case, a detection signal is transmitted from the level sensor 44 to the CPU 25 (S22: YES).

  Then, the CPU 25 that has received the detection signal measures the time until the non-detection signal is received (S26).

  Then, when a preset waiting time elapses without receiving the non-detection signal (S26: YES), the CPU 25 controls the drying blower 18 so that the amount of air blown is reduced, whereby a high temperature drying process is performed. The process is automatically switched from (S2) to the low temperature drying process (S1) (S27).

  Thereby, as shown in FIG. 2, in the high-temperature drying process (S2), when the granule supplied to the molding machine 2 is not consumed, such as when the molding machine 2 is temporarily stopped, the drying device 1 is The process is again switched to the low temperature drying process (S1).

  That is, the low temperature drying process (S1) and the high temperature drying process (S2) are alternately repeated with the consumption of the granular material supplied to the molding machine 2.

  And such a drying process is continued as needed (S3: YES), and is complete | finished after that (S3: NO).

  According to such a method, as shown in FIG. 3 and FIG. 4, in the low temperature drying step, the powder particles in the dry hopper 3 are kept at a low temperature (first step) while restricting the discharge of the powder particles from the dry hopper 3. 1 temperature).

  Thereby, when the powder is not discharged from the drying hopper 3 and the flow of the powder is small, the powder in the drying hopper 3 can be dried at a low temperature (first temperature). In this case, it is possible to suppress blocking of the granular material.

  Moreover, when discharging a granular material from the drying hopper 3, it switches to a high temperature drying process (FIG. 3, S12-S16), and dries the granular material in the drying hopper 3 at high temperature.

  Thereby, when the granular material is discharged from the dry hopper 3 and the granular material is flowing, the granular material in the dry hopper 3 can be dried at a high temperature (second temperature), and the granular material can be efficiently used. The body can be dried.

  Therefore, it is possible to efficiently dry the granular material while suppressing the blocking of the granular material in the drying hopper 3.

  Moreover, according to such a method, as shown in FIG. 1, a low temperature drying process (S1) and a high temperature drying process (S2) can be repeated alternately.

  Therefore, in the dry hopper 3, the dried granular material can be discharged | emitted intermittently, suppressing that a granular material blocks.

  Moreover, according to such a method, as shown in FIG. 3, when the CPU 25 receives a non-detection signal from the level sensor 44 (S12: NO), the high temperature drying process (S2) is switched (S16). As shown in FIG. 4, when the CPU 25 does not receive the non-detection signal for a certain period of time (S26: YES), the process is switched to the low temperature drying step (S1).

  Therefore, the granular material can be dried while supplying the dried granular material to the molding machine 2.

DESCRIPTION OF SYMBOLS 1 Drying apparatus 2 Molding machine 3 Drying hopper 31 Input port 32 Outlet port

Claims (3)

Using a drying apparatus having a drying hopper having a charging port into which a granular material made of a resin material is charged and a discharging port from which the granular material dried from the granular material is discharged, the granular material is A method for producing a dry granular material for drying the granular material before being supplied to a device to be consumed ,
A low-temperature drying step of drying the particles in the drying hopper at a first temperature while closing the discharge port and restricting the discharge of the particles from the drying hopper;
The discharge port is opened to discharge the powder particles from the drying hopper, and when the powder particles discharged from the discharge port are supplied to the supply apparatus, the low temperature drying step is switched, A high temperature drying step of drying the powder particles in a drying hopper at a second temperature higher than the first temperature,
The said 1st temperature and said 2nd temperature are set to the temperature lower than the Vicat softening temperature (JIS K7206, B50 method) of the said granular material, The manufacturing method of the dry granular material characterized by the above-mentioned.   The method for producing a dry granular material according to claim 1, wherein the low temperature drying step and the high temperature drying step are alternately repeated. The drying apparatus, from the previous SL-receiving device is capable of receiving a request signal for requesting the powder or granular material,
When the drying device receives the request signal, it is switched to the high temperature drying process,
The method for producing a dry granular material according to claim 1 or 2, wherein the drying apparatus is switched to the low temperature drying step when the request signal is not received for a certain period of time.

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