JP6644483B2 - Heating device and method of controlling heating device - Google Patents

Description

  The present invention relates to a heating apparatus for a granular material and a method for controlling the heating apparatus.

  2. Description of the Related Art Conventionally, there has been known a heating apparatus that heats a powder or a granular material such as a resin pellet while storing it in a heating hopper. As an example of the heating device, a heating and drying device for heating and drying the granular material is given. Such a heating device has a heating hopper provided with a heating mechanism, and a supply mechanism for supplying the granular material to the heating hopper. A conventional heating device is disclosed, for example, in Patent Document 1.

  The heating device described in Patent Literature 1 is a drying device for heating and drying the powder and granules by supplying warm air to the powder and granules stored inside the drying hopper.

JP 2013-250036 A

  Many of the powder and granular materials such as resin pellets expand when heated, with an increase in temperature. For this reason, when the granular material is heated inside the hopper in which the granular material is stored as in the heating device described in Patent Document 1, the granular material in the hopper expands. When the storage amount of the granular material is large, a vertical pressure is applied to the granular material stored in the lower portion due to the weight of the granular material stored in the upper portion. When the powders expand in this state, a pressing force is applied between the adjacent powders. As a result, there is a possibility that a bridge or blocking may occur in the granular material stored in the lower part of the hopper.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a technology for suppressing occurrence of bridging or blocking of a granular material in a heating device for heating the granular material.

In order to solve the above problems, the first invention of the present application is:
A heating hopper for storing powder and granules inside,
A heating mechanism that heats the powder particles stored inside the heating hopper,
A supply mechanism for supplying the granular material from the upper part of the heating hopper into the heating hopper,
An outlet for discharging the powder and granules stored in the heating hopper from a lower portion of the heating hopper,
A control unit for controlling operations of the heating mechanism and the supply mechanism,
Has,
The control unit, from the empty state of the heating hopper, until the granular material in the heating hopper reaches a predetermined initial upper limit,
A supply step of continuously or intermittently supplying the granular material by the supply mechanism,
A standby step of performing heating by the heating mechanism while stopping the supply mechanism until a predetermined time has elapsed ;
There rows first supply step of repeating, storing the said powder or granular material into the heating hopper,
In the heating device, the predetermined time is a time longer than a time required for the granular material in the heating hopper to expand sufficiently .

A second invention of the present application is a heating hopper for storing powder and granules therein, a heating mechanism for heating the powder and granules stored in the heating hopper, and a heating hopper from above the heating hopper. A supply mechanism for supplying the granular material, a discharge port for discharging the granular material stored in the heating hopper from below the heating hopper, and a control unit for controlling operations of the heating mechanism and the supply mechanism And wherein the control unit controls the supply mechanism to control the supply of the powder and granules from an empty state of the heating hopper until the powder and granular material in the heating hopper reaches a predetermined initial upper limit. Performing a first supply step of repeating a supply step of continuously or intermittently supplying the body and a standby step of performing heating by the heating mechanism while stopping the supply mechanism, and placing the granular material in the heating hopper. Storing and waiting In, heating the powder and granular material to a predetermined temperature is a bridge or blocking hardly occurs temperature even under a load from above, as the heating device.

The third invention of the present application is the heating device according to the first invention or the second invention, wherein in the supply step, a first predetermined amount of the powder particles is an amount that hardly causes a bridge or blocking due to its own weight when heated. The body is fed into the heating hopper .

  A fourth invention of the present application is the heating device according to any one of the first invention to the third invention, wherein a level sensor for detecting a height of the granular material is provided in the heating hopper; When the granular material stored in the heating hopper reaches the initial upper limit, the first supply step is stopped, a second supply step is performed, and the second supply step is performed in the heating hopper. A feedback control step of supplying the granular material to the heating hopper by the supply mechanism when determining that the granular material has fallen below the detection position of the level sensor.

  A fifth invention of the present application is the heating device according to any one of the first invention to the fourth invention, wherein the average supply speed of the powder and granules to the heating hopper by the supply mechanism is equal to or smaller than the powder supply rate from the heating hopper. It is substantially the same as the average discharge speed of the powder and granules from the discharge port after the start of discharge of the granules.

  A sixth invention according to the present application is the heating device according to any one of the first invention to the fifth invention, wherein the control unit heats the powder and granules in the heating hopper by the heating mechanism, thereby controlling the powder. Dry the granules.

A seventh invention of the present application includes a heating hopper provided with a heating mechanism, a supply mechanism for supplying the granular material from an upper portion of the heating hopper, and a discharge port for discharging the granular material from a lower portion of the heating hopper. a method of controlling a heating device, wherein the heating hopper is empty, the step of introducing continuously or intermittently said heating hopper a) before Symbol granular material, b) after said step a) while stopping the supply of the powder or granular material by the feed mechanism, until a predetermined time elapses, by repeating the steps of heating the powder and granular material of the heating hopper, the powder particle in the heating hopper The body is stored, and the predetermined time is a time longer than a time in which the granular material in the heating hopper is sufficiently expanded .
The eighth invention of the present application has a heating hopper provided with a heating mechanism, a supply mechanism for supplying the granular material from an upper portion of the heating hopper, and a discharge port for discharging the granular material from a lower portion of the heating hopper. A method for controlling a heating device, comprising: A) a step of continuously or intermittently charging the powder or granules into the heating hopper from an empty state of the heating hopper; and B) after the step A), Repeating the step of stopping the supply of the granular material by the supply mechanism and heating the granular material in the heating hopper, thereby storing the granular material in the heating hopper, In), the powder is heated to a predetermined temperature at which bridging or blocking hardly occurs even when a load is applied from above.

According to the first to eighth inventions of the present application, the granular material can be stored in the heating hopper while the granular material is heated by an amount that does not easily cause bridging or blocking. Thereby, it is possible to suppress the occurrence of bridging or blocking in the granular material inside the heating hopper.

  In particular, according to the fifth invention of the present application, overdrying of the granular material can be suppressed.

It is the schematic which showed the structure of the heating-drying apparatus which concerns on 1st Embodiment. It is a block diagram showing composition of a control system of a heating drying device concerning a 1st embodiment. It is a flowchart which shows the flow of the heating drying process in the heating drying device which concerns on 1st Embodiment. It is a flowchart which shows the flow of a predetermined amount supply process in the heating drying apparatus which concerns on 1st Embodiment. It is the figure which showed the heating state of the granular material for every area | region of the heating hopper in the heating drying apparatus which concerns on 1st Embodiment. It is the figure which showed the heating state of the granular material for every area | region of the heating hopper in the heating drying apparatus which concerns on 2nd Embodiment. It is the figure which showed the heating state of the granular material for every area | region of the heating hopper in the heating drying apparatus which concerns on 3rd Embodiment. It is the figure which showed the heating state of the granular material for every area | region of the heating hopper in the heating drying device which concerns on 4th Embodiment. It is a flow chart which shows a flow of a heating drying process in a drying device concerning a 4th embodiment. It is a flow chart which shows a flow of a granular material supply process in a heating drying device concerning a modification.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

<1. Heating and drying apparatus according to the first embodiment>
<1-1. Configuration of heating and drying device>
FIG. 1 is a schematic diagram illustrating a configuration of a heating and drying apparatus 1 according to the first embodiment of the present invention. The heating and drying apparatus 1 is an apparatus for heating and drying the resin pellets 9 as powders and supplying the dried resin pellets 9 to a subsequent injection molding machine 8. As shown in FIG. 1, the heating and drying apparatus 1 of the present embodiment includes a heating hopper 20, a heating mechanism 30, a supply mechanism 40, a discharge mechanism 50, and a control unit 60.

  The heating hopper 20 is a container that stores the resin pellets 9 therein. The heating hopper 20 has a substantially cylindrical side wall 21, a funnel-shaped bottom 22 gradually converging downward from the lower end of the side wall 21, and a top plate 23 covering an upper opening of the side wall 21. Inside the heating hopper 20, a space for storing and drying the resin pellets 9 by heating is provided.

  At the upper part of the heating hopper 20, an inlet 201 for introducing the resin pellets 9 into the heating hopper 20 is provided. The charging port 201 of the present embodiment is provided in the top plate 23 of the heating hopper 20. However, the inlet 201 may be provided in the side wall 21 as long as the inlet 201 is located above the heating hopper 20. An outlet 202 for discharging the resin pellets 9 downward from the heating hopper 20 is provided below the heating hopper 20.

  The heating hopper 20 includes a lower sensor 24 and an upper sensor 25. The lower sensor 24 and the upper sensor 25 are level sensors that detect whether the resin pellet 9 has reached a predetermined height.

  The heating mechanism 30 is a mechanism for heating the resin pellets 9 stored inside the heating hopper 20. The heating mechanism 30 includes a heating circulation line 31, a filter 32, a heating blower 33, a heater 34, and an outlet 35.

  The heating circulation line 31 is a piping system that circulates gas to supply hot air for drying into the heating hopper 20. One end of the heating circulation line 31 is connected to a suction port 231 provided in the top plate 23 of the heating hopper 20. The other end of the heating circulation line 31 penetrates the side wall 21 of the heating hopper 20 and is connected to an outlet 35 arranged inside the heating hopper 20. The other end of the heating circulation line 31 may penetrate the top plate 23 of the heating hopper 20 and be connected to the outlet 35. A filter 32, a heating blower 33, and a heater 34 are interposed in the middle of the heating circulation line 31.

  When the heating blower 33 is driven, an airflow is generated in the heating circulation line 31 from the suction port 231 to the outlet 35. The fine dust sucked into the heating circulation line 31 from the heating hopper 20 is collected by the filter 32. The gas that has passed through the filter 32 is heated by the heater 34 to become hot air. Then, the hot air is blown from the outlet 35 into the inside of the heating hopper 20. Note that an adsorber that adsorbs moisture contained in the gas may be provided between the filter 32 and the heater 34.

  The hot air blown out from the outlet 35 is diffused into the heating hopper 20 through a gap between the resin pellets 9 stored in the heating hopper 20. Thereby, the resin pellet 9 is heated, moisture is evaporated from the resin pellet 9, and the resin pellet 9 is dried. That is, the gas diffused in the heating hopper 20 absorbs moisture from the resin pellet 9. Further, the absorbed gas is sucked again from the heating hopper 20 through the suction port 231 to the heating circulation line 31. In addition, the moisture taken in the gas is discharged outside the system of the line 31 while circulating through the circulation line 31 for heating. When the heating circulation line 31 is not provided with a mechanism for discharging the gas in the heating circulation line 31, the heating circulation line 31 is replaced with a degassing device for adsorbing moisture contained in the gas in the heating circulation line 31. A wet device may be provided.

  The supply mechanism 40 is a mechanism for supplying the resin pellets 9 to the heating hopper 20. The supply mechanism 40 includes a storage hopper 41, a supply pipe 42, a supply hopper 43, a supply circulation line 44, a filter 45, and a supply blower 46.

  The storage hopper 41 is a container that stores therein the resin pellets 9 before drying. The storage hopper 41 includes a substantially cylindrical tubular portion 411, a funnel-shaped funnel portion 412 that gradually converges from the lower end portion of the tubular portion 411 downward, and a lid portion 413 that covers an upper opening of the tubular portion 411. Having. The lower end of the funnel 412 is connected to the upper end of the supply pipe 42 extending vertically. The lower end of the supply pipe 42 is connected to the middle of the supply circulation line 44. Thereby, the resin pellets 9 stored in the storage hopper 41 are supplied into the supply circulation line 44 through the supply pipe 42 by gravity.

  The supply hopper 43 is installed above the heating hopper 20. The supply hopper 43 is a container that temporarily stores the resin pellets 9 when the resin pellets 9 are supplied to the heating hopper 20. The supply hopper 43 is connected to the heating hopper 20 via an openable opening 201 provided in the top plate 23 of the heating hopper 20.

  The supply circulation line 44 is a piping system for circulating gas in order to transport the resin pellets 9 stored in the storage hopper 41 to the supply hopper 43. The upstream end of the supply circulation line 44 is connected to an intake port 431 provided above the supply hopper 43. The downstream end of the supply circulation line 44 is connected to a supply port 432 provided on the side of the supply hopper 43. The supply port 432 is provided with a punched metal plate 433 having a plurality of through holes. The punching metal plate 433 restricts passage of the resin pellets 9 and allows passage of gas.

  A filter 45 and a supply blower 46 are interposed in the middle of the supply circulation line 44. The lower end of the supply pipe 42 is connected to the supply circulation line 44 on the downstream side of the filter 45 and the supply blower 46.

  When the supply blower 46 is driven, an airflow from the intake port 431 to the supply port 432 is generated in the supply circulation line 44. Then, the resin pellets 9 supplied from the storage hopper 41 into the supply circulation line 44 via the supply pipe 42 are conveyed downstream in the supply circulation line 44 by the airflow. Thus, the resin pellets 9 are pneumatically conveyed from the storage hopper 41 to the supply hopper 43.

  The fine dust sucked from the supply hopper 43 into the supply circulation line 44 is collected by the filter 45. The movement of the resin pellets 9 from the supply hopper 43 to the supply circulation line 44 is blocked by the punching metal plate 433. Therefore, the resin pellets 9 are supplied into the supply hopper 43 without flowing into the supply circulation line 44.

  After the supply of the resin pellets 9 in the supply hopper 43 and the stopping of the pneumatic conveyance by the supply blower 46, the resin pellets 9 are supplied from the supply hopper 43 into the heating hopper 20 through the input port 201. As described above, the resin pellets 9 are stored in the heating hopper 20 by repeating the pneumatic conveyance of the resin pellets 9 from the storage hopper 41 to the heating hopper 20 and the stop of the pneumatic conveyance.

  The discharging mechanism 50 is a mechanism for discharging the resin pellets 9 from the inside of the heating hopper 20. The discharge mechanism 50 has a discharge pipe 51 extending downward from a discharge port 202 of the heating hopper 20, and a shutter 52 for restricting movement of the resin pellet 9 in the discharge pipe 51. The lower end of the discharge pipe 51 is connected to the injection molding machine 8.

  Although the shutter 52 of the present embodiment is opened and closed manually, the control unit 60 may automatically open and close the shutter 52. When the shutter 52 is opened, the resin pellets 9 stored in the lower part of the heating hopper 20 can be discharged downward through the discharge port 202 and the discharge pipe 51 due to gravity. When the shutter 52 is closed, the discharge of the resin pellets 9 from the heating hopper 20 is stopped.

  In the present embodiment, as the resin pellets 9 are consumed by the injection molding machine 8, the resin pellets 9 are discharged from the inside of the heating hopper 20 to the injection molding machine 8. That is, even if the shutter 52 is opened, the resin pellet 9 is not discharged from the inside of the heating hopper 20 to the injection molding machine 8 unless the resin pellet 9 is consumed in the injection molding machine 8. For this reason, after the discharge pipe 51 and the injection molding machine 8 are connected, the shutter 52 is kept open during the driving period of the heating and drying device 1.

  FIG. 2 is a block diagram illustrating a configuration of a control system of the heating and drying apparatus 1. The control unit 60 is a unit for controlling the operation of each unit of the heating and drying apparatus 1. As shown in FIG. 2, the control unit 60 is electrically connected to the lower sensor 24, the upper sensor 25, the heating blower 33, the heater 34, and the supply blower 46, respectively. The control unit 60 of the present embodiment is configured by a computer having an arithmetic processing unit such as a CPU and a memory. However, the control unit 60 may be configured by an electronic circuit. The control unit 60 controls the operation of each of the above-described units based on a preset program or an external input signal. Thereby, the heating and drying process of the resin pellets 9 in the heating and drying device 1 proceeds.

<1-2. Operation of heating and drying device>
Next, the processing of the resin pellets 9 in the heating and drying apparatus 1 will be described with reference to FIGS. FIG. 3 is a flowchart showing the flow of the heating and drying process in the heating and drying apparatus 1. FIG. 4 is a flowchart showing the flow of the predetermined amount supply process in the heating and drying apparatus 1.

  In the heating and drying apparatus 1, when processing the resin pellets 9, first, the heating hopper 20 is subjected to the first supply step (steps S11 to S14) from an empty state, so that the initial upper limit amount is set in the heating hopper 20. Is stored. Then, a second supply step (steps S15 to S17) of supplying the resin pellets 9 is performed while performing feedback control according to the consumption amount of the resin pellets 9 in the heating hopper 20.

  In the first supply step, first, the control unit 60 starts heating the heating hopper 20 by the heating mechanism 30 (step S11). That is, the control unit 60 starts driving the heating blower 33 and the heater 34. After a lapse of a predetermined time from the start of heating, the process proceeds to step S12. When the heating hopper 20 has a temperature sensor for measuring the internal temperature, the process may proceed to step S12 when the temperature in the heating hopper 20 reaches a predetermined temperature.

  Next, a predetermined amount supply step of putting a first predetermined amount of the resin pellets 9 into the heating hopper 20 is performed (step S12). Specifically, the “first predetermined amount” in the predetermined amount supply step means an amount of the resin pellet 9 that is less likely to cause a bridge or blocking due to its own weight when the resin pellet 9 is heated.

  When the resin pellets 9 are heated, each of the resin pellets 9 expands as the temperature rises. At this time, the lower resin pellet 9 receives a vertical pressure due to the weight of the upper resin pellet 9. When the resin pellet 9 expands, the resin pellet 9 is pressed against the side wall 21 of the heating hopper 20. As a result, a pressure is applied to the resin pellet 9 from the side wall 21 toward the inside. Therefore, when the storage height of the resin pellets 9 is large, or when the storage height of the resin pellets 9 is large with respect to the diameter of the heating hopper 20 in the horizontal direction, the pressure between the resin pellets 9 increases, and a bridge or blocking occurs. There is a fear. Therefore, the "first predetermined amount" in the predetermined amount supply step (step S12) is, for example, the type of the resin pellet 9, the height of the resin pellet 9 in the heating hopper 20, the diameter of the heating hopper 20 in the horizontal direction. Is preferably defined by

  The heating and drying apparatus 1 of the present embodiment has a supply mechanism 40 for performing so-called batch transport. Therefore, the predetermined amount supply step includes a plurality of batch transportation steps in order to supply the first predetermined amount of the resin pellets 9. Here, the first predetermined amount is X [kg], the batch transport amount that can be transported in one batch transport is x [kg], and the quotient obtained by dividing X by x is N [times]. In this case, the supply mechanism 40 performs the normal batch transportation N times. In addition, the batch transport amount x [kg] per one time is adjusted so that N is an integer. The flow of the predetermined amount supply step at this time will be described with reference to FIG.

  The control unit 60 first sets the count number n to 0 (step S121). Next, it is determined whether or not the count number n is smaller than the number N of normal batch transportation (step S122). If it is determined in step S122 that the count number n is smaller than the number N of normal batch transportation, the control unit 60 causes the supply mechanism 40 to perform normal batch transportation (step S123). After that, the count number n is incremented (step S124). As described above, the count number n is a value indicating the number of times the normal batch transportation is performed.

  If it is determined in step S122 that the count number n is equal to or larger than the number N of the normal batch transportation, the control unit 60 ends the predetermined amount supply step. Thereby, the resin pellets 9 of the first predetermined amount X [kg] can be put into the heating hopper 20.

  Subsequently, the supply mechanism 40 waits until a predetermined time elapses (step S13). That is, the control unit 60 causes the supply mechanism 40 to supply the first predetermined amount of the resin pellets 9 to the heating hopper 20, and then performs heating by the heating mechanism 30 until the predetermined time elapses. The supply of the resin pellets 9 to the heating hopper 20 is stopped.

  During the standby step in step S13, the resin pellets 9 put into the heating hopper 20 in the predetermined amount supply step (step S12) are heated and expand with the rise in temperature. The “predetermined time” in this standby step is a time longer than the time during which the resin pellet 9 expands sufficiently.

  In the present embodiment, the predetermined time is a time empirically determined in advance. However, based on a signal from a temperature sensor provided in the heating hopper 20, the standby step of step S13 may be ended when the temperature at which the resin pellets 9 sufficiently expand is reached. If the temperature of the resin pellet 9 rises to a predetermined temperature and the resin pellet 9 expands sufficiently, even if the subsequent resin pellet 9 receives a load from above, bridging or blocking hardly occurs. As described above, in step S13, the control unit 60 stops the supply of the resin pellets 9 to the heating hopper 20 by the supply mechanism 40 until the resin pellets 9 are heated to a predetermined temperature or higher.

  After the standby step in step S13, the control unit 60 determines whether a second predetermined amount of the resin pellets 9 has been stored in the heating hopper 20 (step S14). When the second predetermined amount of the resin pellets 9 is not stored, the process returns to step S12, and the predetermined amount supply step is performed again. On the other hand, when the second predetermined amount of the resin pellets 9 is stored, the process proceeds to step S15, and shifts to the second supply process. In the first supply step, the storage amount of the resin pellets 9 in the heating hopper 20 increases every time the predetermined amount supply step of step S12 is performed. Then, the controller 60 repeats the predetermined amount supply step and the standby step until the resin pellets 9 stored in the heating hopper 20 reach the second predetermined amount. That is, the “second predetermined amount” is an “initial upper limit amount” that is the upper limit amount of the resin pellet 9 in the first supply step.

  The “second predetermined amount” in step S14 is, specifically, the amount by which the resin pellets 9 in the heating hopper 20 reach above the detection position of the lower sensor 24. That is, the second predetermined amount is an amount larger than the lower limit amount in the second supply step which is the feedback control after step S15. Note that the second predetermined amount is preferably an amount in which the resin pellet 9 in the heating hopper 20 reaches a position above the detection position of the upper sensor 25.

  Whether or not the resin pellets 9 charged into the heating hopper 20 have reached the second predetermined amount may be determined by the number of times the predetermined amount supply step of step S12 has been performed, or The determination may be made based on whether a predetermined height has been reached.

  In the present embodiment, the start of heating (step S11) is performed before the start of the first predetermined amount supply step (step S12) of the first supply step. However, the start of the heating (step S11) may be simultaneous with the start of the first predetermined amount supply step (step S12), or in the middle of or immediately after the first predetermined amount supply step (step S12). You may.

  As in the present embodiment, when the inside of the heating hopper 20 is sufficiently heated before the start of the first predetermined amount supply step (step S12), the first standby step (step S13) and the second and subsequent standby steps The standby time in (Step S13) can be set to be the same.

  However, if the inside of the heating hopper 20 is not sufficiently heated before the start of the first supply step (steps S11 to S14), the standby time in the first standby step (step S13) is equal to or less than the second standby step (step S13). It is preferable to set longer than the standby time in step S13). This suppresses the second predetermined amount supply step (Step S12) from being performed in a state where the heating of the resin pellets 9 supplied in the first predetermined amount supply step (Step S12) is insufficient. Therefore, pressure is applied from above before the expansion of the resin pellets 9 input in the first predetermined amount supply step (Step S12) is completed, and the occurrence of bridges and blocking in the resin pellets 9 is suppressed.

  In step S14, when it is determined that the amount of the resin pellets 9 charged into the heating hopper 20 has reached the second predetermined amount, the control unit 60 stops the first supply step in steps S11 to S14 and proceeds to the second supply step. Switch. The second supply step is a feedback control using the lower sensor 24 and the upper sensor 25. In the second supply step, the supply of the resin pellets 9 into the heating hopper 20 is performed according to the discharge of the resin pellets 9 from the discharge port 202.

  In the second supply step, the control unit 60 first determines whether or not the lower sensor 24 has detected the resin pellet 9 (Step S15). That is, it is determined whether or not the surface of the resin pellet 9 in the heating hopper 20 is below the lower sensor 24. In step S15, if the lower sensor 24 detects the resin pellet 9, that is, if the surface of the resin pellet 9 in the heating hopper 20 is above the lower sensor 24, the control unit 60 proceeds to step S15. Return and wait.

  In step S15, when the lower sensor 24 stops detecting the resin pellet 9, that is, the resin pellet 9 in the heating hopper 20 is periodically discharged from the discharge port 202, and the surface of the resin pellet 9 is If it has dropped below the detection position 24, the process proceeds to step S16. Then, the control unit 60 causes the supply mechanism 40 to perform the normal batch transport similar to step S12 once (step S16).

  Thereafter, the controller 60 determines whether or not the upper sensor 25 has detected the resin pellet 9 (Step S17). If it is determined in step S17 that the upper sensor 25 has not detected the resin pellet 9, the control unit 60 returns to step S16 and causes the supply mechanism 40 to perform normal batch transport again.

  On the other hand, if it is determined in step S17 that the upper sensor 25 has detected the resin pellet 9, the control unit 60 returns to step S15, and waits until the surface of the resin pellet 9 falls below the lower sensor 24. As described above, in the second supply process of steps S15 to S17, the resin pellets 9 are sequentially supplied to the heating hopper 20 in accordance with the supply speed to the injection molding machine 8 by feedback control.

  As described above, in the second supply step, when it is determined that the resin pellets 9 in the heating hopper 20 have not reached the lower sensor 24, a feedback control step of supplying the resin pellets 9 to the heating hopper 20 by the supply mechanism 40. It is.

<1-3. About the dry state in the heating hopper>
Next, the heating state of the resin pellets 9 in the heating hopper 20 during the heating and drying process will be described in detail with reference to FIG. FIG. 5 is a diagram showing a heating state of the resin pellets 9 for each region in the heating hopper 20.

  The heating and drying apparatus 1 of the first embodiment discharges the resin pellets 9 that have been subjected to the heating and drying treatment in the heating hopper 20 for 5 hours or more to the injection molding machine 8 at a speed of 1 [kg / h]. . The ejection of the resin pellets 9 to the injection molding machine 8 is not always performed at a constant speed, but is performed intermittently. Therefore, the discharge speed is an average value per unit time. In the heating and drying apparatus 1, six regions from a first region to a sixth region are conceptually set in the internal space of the heating hopper 20.

  The first region is a region that is filled with the resin pellets 9 when 1 kg of the resin pellets 9 is stored in the heating hopper 20. The second region is a region obtained by removing the first region from a region filled with the resin pellets 9 when 2 kg of the resin pellets 9 are stored in the heating hopper 20. The third region is a region where the first region and the second region are removed from a region filled with the resin pellets 9 when 3 kg of the resin pellets 9 are stored in the heating hopper 20. The same applies to the fourth to sixth areas.

  In FIG. 5, the elapsed time indicates the elapsed time from when the first predetermined amount supply step (step S12) is completed. Further, in FIG. 5, in each box, a granular material identification display indicated by alphabets such as A, B, and C, and a drying time shown in parentheses after the granular material identification display are displayed. In addition, the granular material identification display is given in order from A in the same order as the alphabet, from the one put into the heating hopper 20 for every 1 kg.

  In the first embodiment, if it is 3 [kg], it is assumed that bridging and blocking hardly occur due to expansion due to heating. In the first embodiment, the resin pellets 9 of 3 kg are subjected to the heating and drying process in the heating hopper 20 for 0.5 h, so that the resin pellets 9 expand sufficiently. Therefore, in the first embodiment, the first predetermined amount is 3 [kg], and the “predetermined time” in step S13 is 0.5 [h].

  In such a heating and drying apparatus 1, a first predetermined amount supply step (step S12) is performed in a state where the discharge of the resin pellets 9 to the injection molding machine 8 is stopped. Thereby, 3 kg of resin pellets 9 indicated by A, B, and C are put into the empty heating hopper 20. Therefore, the first region is filled with resin pellets 9 represented by A, the second region is represented by B, and the third region is represented by C. After that, 0.5 [h] heat drying processing is performed on the resin pellets 9 of A, B, and C (a standby step in step S13). By heating, the resin pellets 9 of A, B and C expand sufficiently.

  Next, when the elapsed time reaches 0.5 [h], a second predetermined amount supply step (step S12) is performed, and 3 [kg] resin pellets 9 indicated by D, E, and F are formed. It is put into the heating hopper 20. At this time, the resin pellets 9 of D, E, and F are put on the resin pellets 9 of A, B, and C that have sufficiently expanded. As a result, the fourth region is filled with resin pellets 9 indicated by D, the fifth region by E, and the sixth region by F. Then, after that, 0.5 [h] heat drying treatment is performed on the resin pellets 9 of A to F (step S13). By heating, the resin pellets 9 of D, E, and F expand sufficiently.

  In the first embodiment, 6 kg is set as the second predetermined amount. For this reason, when the elapsed time reaches 1 [h], the resin pellet 9 in the heating hopper 20 has reached 6 [kg], and the control unit 60 changes the supply method from the first supply step to the second supply step. Switch to supply process. In addition, it is preferable that both the lower sensor 24 and the upper sensor 25 are arranged near the upper end of the sixth region.

  In the first embodiment, as described above, the resin pellets 9 that have been subjected to the heat drying process in the heating hopper 20 for 5 hours or more are supplied to the injection molding machine 8. Therefore, the resin pellets 9 are not discharged to the injection molding machine 8 until the elapsed time reaches 5 [h] and the heating and drying time of the A stored at the bottom reaches 5 hours. Then, when the elapsed time reaches 5 [h], the discharge of the resin pellets 9 to the injection molding machine 8 is started at a speed of 1 [kg / h]. When the discharge of the resin pellets 9 to the injection molding machine 8 is started, the respective steps of the second supply step also proceed, and the resin pellets 9 indicated by G ′, H ′, I ′, etc. It is thrown into.

  In FIG. 5, the resin pellets 9 supplied in the second supply step are easily distinguished from each other in the first supply step and the resin pellets 9 supplied in the second supply step. “′” Is attached to the granular material identification display. The resin pellets 9 supplied in the second supply step are supplied little by little, so that there is a wide range of drying time, but for each 1 kg, the drying time is n [h] to n + 1 [h]. Is described in parentheses in FIG. 5 as “n”.

  At the time when the elapsed time becomes 6 [h], all the resin pellets 9 of A stored in the first area at the time of 5 [h] are discharged, and the resin pellet 9 of B is discharged to the first area. Is stored. Then, the resin pellets 9 indicated by G ', which have been injected in the second supply step during the elapsed time of 5 [h] to 6 [h], are stored in the sixth region.

  When the elapsed time reaches 7 [h], all the B resin pellets 9 stored in the first area at the time when the elapsed time is 6 [h] are discharged, and the C resin pellet is discharged to the first area. Pellets 9 are stored. Then, the resin pellets 9 indicated by H ′, which have been injected in the second supply step during the elapsed time from 6 [h] to 7 [h], are stored in the sixth region.

  As described above, in the example of FIG. 5, when the resin pellets 9 are initially charged, in the first supply step, the resin pellets in the heating hopper 20 are changed from the empty state to the second predetermined amount of 6 [kg]. ], The first predetermined amount of the resin pellets 9 of 3 [kg] and the standby of 0.5 [h] are repeated. By doing so, it is possible to suppress the occurrence of bridges and blocking in the resin pellets 9 in the heating hopper 20 due to expansion due to heating of the resin pellets 9 and pressure from above.

<2. Second Embodiment>
Subsequently, the supply, discharge, and heating states of the resin pellets 9 during the heating and drying process in the heating and drying apparatus 1 according to the second embodiment will be described with reference to FIG. FIG. 6 is a diagram illustrating a heating state of the resin pellet 9 in each region of the heating hopper 20 in the second embodiment. Note that the configuration of the heating and drying apparatus 1 according to the second embodiment is the same as that of the first embodiment, and a description thereof will be omitted.

  In the second embodiment, the resin pellets 9 that have been subjected to the heat drying treatment in the heating hopper 20 for 2 hours or more are discharged to the injection molding machine 8 at a speed of 1 [kg / h]. In the second embodiment, if the weight is 1 [kg], bridging and blocking hardly occur due to expansion due to heating. In the second embodiment, it is assumed that the resin pellet 9 of 1 [kg] is sufficiently dried by heating and drying in the heating hopper 20 for 0.5 [h]. For this reason, in the second embodiment, the first predetermined amount is set to 1 [kg], and the “predetermined time” in step S13 is set to 0.5 [h]. In addition, the second predetermined amount in the second embodiment is set to 6 [kg] as in the first embodiment.

  First, in a state where the discharge of the resin pellets 9 to the injection molding machine 8 is stopped, a first predetermined amount supply step (Step S12) is performed. As a result, 1 kg of the resin pellet 9 indicated by A is put into the empty heating hopper 20. Therefore, the first region is filled with the resin pellet 9 indicated by A. Then, a heating and drying process of 0.5 [h] is performed on the resin pellet 9 of A (step S13). By heating, the resin pellet 9 of A expands sufficiently.

  Next, when the elapsed time reaches 0.5 [h], a second predetermined amount supply step (step S12) is performed. As a result, 1 kg of the resin pellet 9 indicated by B is put into the heating hopper 20. Therefore, the second region is filled with the resin pellet 9 indicated by B. Then, the heating and drying process of 0.5 [h] is performed on the resin pellets 9 of A and B (step S13). By heating, the resin pellet 9 of B also expands sufficiently.

  Similarly, when the elapsed time reaches 1 [h], the third predetermined amount supply step is performed. When the elapsed time reaches 1.5 [h], the fourth predetermined amount supply step is performed. Thus, the third region is filled with 1 kg of resin pellet 9 indicated by C, and after the resin pellet 9 of C is sufficiently expanded, the fourth region is filled with 1 kg of resin indicated by D. The pellet 9 is filled.

  When the elapsed time reaches 2 [h], a fifth predetermined amount supply step is performed, and the discharge of the resin pellets 9 to the injection molding machine 8 is started. Thus, the fifth region is filled with 1 kg of the resin pellet 9 indicated by E, and the discharge of the resin pellet 9 from the discharge port 202 is started. At this time, the resin pellet 9 of D which was charged last time is sufficiently expanded.

  When the elapsed time reaches 2.5 [h], the sixth predetermined amount supply step is performed. As a result, 1 kg of the resin pellet 9 indicated by F is put into the heating hopper 20. At this time, the resin pellets 9 of E which have been charged last time are sufficiently expanded. At this time, the amount of the resin pellets 9 discharged from the discharge port 202 is about 0.5 [kg]. Therefore, as shown in FIG. 6, resin pellets 9 of A and B are provided in the first region, resin pellets 9 of B and C are provided in the second region, and resin pellets 9 of C and D are provided in the third region. D and E resin pellets 9 are stored in the region, and E and F resin pellets 9 are stored in the fifth region. Also, F resin pellets 9 are stored in a part of the sixth region.

  Subsequently, when the elapsed time reaches 3 [h], a seventh predetermined amount supply step is performed. Thereby, 1 kg of the resin pellet 9 indicated by G is put into the heating hopper 20. At this time, the resin pellet 9 of F which has been charged last time is sufficiently expanded. At this time, the total amount of the resin pellets 9 discharged from the discharge port 202 is 1 [kg]. That is, all the resin pellets 9 of A are discharged. Therefore, the B resin pellets 9 are stored in the first region, and the G resin pellets 9 are stored in the sixth region.

  When the elapsed time reaches 3 [h] and the seventh predetermined amount supply step is performed, the resin pellets 9 in the heating hopper 20 reach the second predetermined amount of 6 [kg]. Therefore, after a predetermined time of 0.5 [h] has elapsed from this point, the control unit 60 switches the supply method from the first supply step to the second supply step. Thereafter, since the resin pellets 9 are continuously discharged to the injection molding machine 8 at a speed of 1 [kg / h], each step of the second supply step proceeds, and is indicated by H ′, I ′, J ′, and the like. The resin pellets 9 to be discharged are sequentially put into the heating hopper 20.

  As in the second embodiment, the resin pellets 9 may be discharged to the injection molding machine 8 before the first supply step is completed. Even in this case, when the resin pellets 9 are initially charged, the first predetermined amount of the resin of 1 [kg] and the standby of 0.5 [h] are repeated in the first supply step. By doing so, it is possible to suppress the occurrence of bridges and blocking in the resin pellets 9 in the heating hopper 20 due to expansion due to heating of the resin pellets 9 and pressure from above.

<3. Third Embodiment>
Subsequently, the supply, discharge, and heating states of the resin pellets 9 during the heating and drying process in the heating and drying apparatus 1 according to the third embodiment will be described with reference to FIG. FIG. 7 is a diagram illustrating a heating state of the resin pellet 9 in each region of the heating hopper 20 in the third embodiment. Note that the configuration of the heating and drying apparatus 1 according to the third embodiment is the same as that of the first embodiment, and a description thereof will not be repeated.

  In the third embodiment, the resin pellets 9 that have been subjected to the heat drying treatment in the heating hopper 20 for 5 hours or more are discharged to the injection molding machine 8 at a speed of 1 [kg / h]. In the third embodiment, if the weight is 2 kg, bridging and blocking hardly occur due to expansion due to heating. Further, in the third embodiment, it is assumed that the resin pellets 9 of 2 [kg] are heated and dried in the heating hopper 20 for 0.5 [h] so that the resin pellets 9 expand sufficiently. That is, in the third embodiment, the first predetermined amount is 2 [kg]. In addition, the second predetermined amount in the third embodiment is set to 6 [kg] as in the first embodiment.

  In the third embodiment, the “predetermined time” in step S13 is set to a time longer than 0.5 [h] instead of the heating time 0.5 [h] for sufficiently expanding the resin pellet 9. . Specifically, when the first supply step includes k predetermined amount supply steps (step S12) and a standby step (step S13), the “predetermined time” (step S13) in the first to (k−1) th steps S13 Hereinafter, “the first predetermined time” is set to 2 [h], and the “predetermined time” (hereinafter, referred to as the “second predetermined time”) in the k-th step S13, which is the last round, is set to 1 [h]. I do.

  The first predetermined time 2 [h] is the same as the time required to discharge the first predetermined amount 2 [kg] to the injection molding machine 8 at a speed of 1 [kg / h]. As described above, in the third embodiment, the first predetermined time is set to be a quotient obtained by dividing the first predetermined amount by the discharge speed to the injection molding machine 8. As a result, the average supply speed of the resin pellets 9 to the heating hopper 20 in the first supply step and the average discharge speed of the resin pellets 9 from the heating hopper 20 after the start of discharge become substantially the same.

  First, in a state where the discharge of the resin pellets 9 to the injection molding machine 8 is stopped, a first predetermined amount supply step (Step S12) is performed. As a result, 2 kg of resin pellets 9 indicated by A and B are put into the empty heating hopper 20. Therefore, the first region is filled with the resin pellet 9 indicated by A, and the second region is filled with the resin pellet 9 indicated by B. After that, the heating and drying treatment of 2 [h], which is the first predetermined time, is performed on the resin pellets 9 of A and B (step S13). By heating, the resin pellets 9 of A and B expand sufficiently.

  Next, when the elapsed time reaches 2 [h], a second predetermined amount supply step (step S12) is performed. Thus, 2 kg of resin pellets 9 indicated by C and D are charged into the heating hopper 20. Therefore, the third region is filled with the resin pellet 9 indicated by C, and the fourth region is filled with the resin pellet 9 indicated by D. Then, the heat drying process of 2 [h], which is the first predetermined time, is performed on the resin pellets 9 of A, B, C, and D (step S13). By heating, the C and D resin pellets 9 also expand sufficiently.

  Similarly, when the elapsed time reaches 4 [h], a third predetermined amount supply step (step S12) is performed. Thereby, 2 kg of resin pellets 9 indicated by E and F are put into the heating hopper 20. Therefore, the fifth region is filled with the resin pellet 9 indicated by E, and the sixth region is filled with the resin pellet 9 indicated by G. Then, a heat drying process of 1 [h], which is the second predetermined time, is performed on the resin pellets 9 of A, B, C, D, E, and F (Step S13). By heating, the resin pellets 9 of E and F also expand sufficiently.

  When the elapsed time reaches 5 [h], the discharge of the resin pellets 9 to the injection molding machine 8 is started. At the same time, the control unit 60 switches the supply method from the first supply step to the second supply step. Thereafter, since the resin pellets 9 are continuously discharged to the injection molding machine 8 at a speed of 1 [kg / h], each step of the second supply step proceeds, and is indicated by G ′, H ′, I ′, and the like. The resin pellets 9 to be discharged are sequentially put into the heating hopper 20.

  Here, with reference to FIG. 5, a comparison is made with the heating and drying time of the resin pellet 9 in the first embodiment. As shown in FIG. 5, in the first embodiment, when the elapsed time reaches 10 [h], the heating and drying time of the resin pellets stored in the first region is 9.5 [h]. Therefore, the heating and drying time of the resin pellets 9 discharged to the injection molding machine 8 is 5 hours or more and less than 10.5 hours. That is, the heating and drying time of the resin pellets 9 varies by 5 hours or more.

  On the other hand, in the third embodiment, the supply speed of the resin pellets 9 in the first supply step is adjusted to the discharge speed of the resin pellets 9 to the injection molding machine 8. In this way, as shown in FIG. 7, during the period when the resin pellets 9 are discharged to the injection molding machine 8 after the elapsed time 5 [h], the heating of the resin pellets stored in the first region is performed. The drying time is 5 hours or more and less than 7 hours. That is, the variation in the heating and drying time of the resin pellet 9 can be reduced. Thereby, overdrying of the resin pellet 9 can be suppressed.

  Depending on the type of the resin pellets 9, it may be necessary to change the molding conditions on the side of the injection molding machine 8 because the heating and drying time becomes longer than necessary. When processing such a resin pellet 9, it is preferable to adjust the supply speed of the resin pellet 9 in the first supply step to the discharge speed of the resin pellet 9 to the injection molding machine 8, as in the third embodiment. .

<4. Fourth embodiment>
Next, the supply, discharge, and heating states of the resin pellets 9 during the heating and drying process in the heating and drying apparatus 1 according to the fourth embodiment will be described with reference to FIG. FIG. 8 is a diagram illustrating a heating state of the resin pellet 9 in each region of the heating hopper 20 in the fourth embodiment. FIG. 9 is a flowchart showing the flow of the heating and drying process in the fourth embodiment. Note that the configuration of the heating and drying apparatus 1 according to the fourth embodiment is the same as that of the first embodiment, and a description thereof will not be repeated.

  In the fourth embodiment, the resin pellets 9 that have been subjected to the heat drying treatment in the heating hopper 20 for 5 hours or more are discharged to the injection molding machine 8 at a speed of 1 [kg / h]. In the fourth embodiment, if the weight is 2 kg, bridging and blocking hardly occur due to expansion due to heating. Further, in the fourth embodiment, it is assumed that the resin pellet 9 of 1 [kg] is heated and dried in the heating hopper 20 for 0.5 [h] so that the resin pellet 9 expands sufficiently. In the fourth embodiment, the first predetermined amount is set to 1 kg, which is smaller than 2 kg.

  In the fourth embodiment, the “predetermined time” in step S13 is not the heating time 0.5 [h] for sufficiently expanding the resin pellet 9 but a time longer than 0.5 [h]. Set to [h]. The “predetermined time” of 1 [h] is the same as the time required to discharge the first predetermined amount of 1 [kg] to the injection molding machine 8 at a speed of 1 [kg / h]. . Thus, in the fourth embodiment, as in the third embodiment, the first predetermined time is set to be a quotient obtained by dividing the first predetermined amount by the discharge speed to the injection molding machine 8. As a result, the average supply speed of the resin pellets 9 to the heating hopper 20 and the average discharge speed of the resin pellets 9 from the heating hopper 20 after the start of discharge become substantially the same.

  First, in a state where the discharge of the resin pellets 9 to the injection molding machine 8 is stopped, a first predetermined amount supply step (Step S12) is performed. As a result, 1 kg of the resin pellet 9 indicated by A is put into the empty heating hopper 20. Therefore, the first region is filled with the resin pellet 9 indicated by A. After that, the resin pellet 9 of A is subjected to a heat drying process of 1 [h] for a predetermined time (step S13). By heating, the resin pellet 9 of A expands sufficiently.

  Thereafter, such a predetermined amount supply step (step S12) and a standby step (step S13) are repeated. Thus, every 1 hour, 1 kg of resin pellets indicated by B, C, D, and E are supplied to the heating hopper 20. When the elapsed time reaches 5 [h], the sixth predetermined amount supply step (step S12) is started, and at the same time, the discharge of the resin pellets 9 to the injection molding machine 8 is started. At this time, the 6th area is filled with 1 kg of resin pellet 9 indicated by F.

  In the fourth embodiment, the supply method is not switched from the first supply step to the second supply step even after all of the first to sixth areas are filled with the resin pellets 9. Therefore, as shown in FIG. 9, the control unit 60 repeats the first supply step shown in steps S11 to S13. For this reason, after the elapsed time of 5 [h] has elapsed, the resin pellets 9 are discharged to the injection molding machine 8 at a speed of 1 [kg / h], while once every hour, [Kg] of resin pellets 9 is charged. Thus, even after the F resin pellets 9 are charged, 1 kg of resin pellets indicated by G and H are supplied to the heating hopper 20 every hour. Thereafter, 1 kg of resin pellets are similarly supplied every hour.

  As in the fourth embodiment, the supply speed of the resin pellets 9 in the first supply step is adjusted to the discharge speed of the resin pellets 9 to the injection molding machine 8, and the resin pellets 9 are supplied to the heating hopper 20 only by the first supply step. 9 may be input. This eliminates the need to perform feedback control as in the second supply step. Further, as shown in FIG. 8, during the period when the material is discharged to the injection molding machine 8 after the elapsed time 5 [h], the heating and drying time of the resin pellets 9 stored in the first area is set to 5 hours. It can be less than 6 hours. That is, the variation in the heating and drying time of the resin pellets 9 can be further reduced as compared with the third embodiment. As a result, overdrying of the resin pellet 9 can be further suppressed.

<5. Modification>
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to said Embodiment.

  FIG. 10 is a flowchart illustrating a flow of a heating and drying process of the heating and drying apparatus according to a modification. This heating / drying apparatus has the same configuration as the heating / drying apparatus 1 according to the first embodiment except that it does not have an upper sensor.

  In the example of FIG. 10, the first supply process in steps S11 to S14 is the same as in the first embodiment. On the other hand, the second supply process includes Step S15 similar to the first embodiment and Step S18 different from the first embodiment.

  In the second supply process of the example of FIG. 10, when it is determined in step S15 that the lower sensor 24 has detected the resin pellet 9, the process returns to step S15 and waits, as in the first embodiment. If it is determined in step S15 that the lower sensor 24 has not detected the resin pellet 9, the process proceeds to step S18. Then, the control unit 60 causes the supply mechanism 40 to perform the normal batch transport a predetermined number of times (step S18). The number m of batch transports in step S18 may be one or more. Then, when step S18 ends, the process returns to step S15.

  As in the example of FIG. 10, the heating hopper 20 does not have to have two level sensors. If the heating hopper 20 has at least one level sensor, feedback control in the second supply step can be performed.

  Further, in each of the above embodiments, the supply mechanism 40 performs the so-called batch transport in which the resin pellets 9 are intermittently supplied into the heating hopper 20. However, the supply mechanism of the present invention may be one that continuously supplies resin pellets into the heating hopper.

  In each of the above embodiments, the supply mechanism 40 supplies the resin pellets 9 into the heating hopper 20 by pneumatic transportation. However, the supply mechanism 40 may be another form of supply mechanism such as a screw feeder.

  In the first and second embodiments, in the first supply step, it is determined whether or not the supplied resin pellets have sufficiently expanded based on whether or not a predetermined time has elapsed. However, a temperature sensor is provided in the heating hopper, and the control unit determines whether the temperature in the heating hopper has reached a predetermined temperature based on a signal from the temperature sensor. You may judge whether it expanded enough.

  Further, the heating device of the above embodiment is a heating and drying device that heats and dries the powder and granules stored in the heating hopper by the heating mechanism sending hot air into the heating hopper. Not limited to The heating device of the present invention may simply increase the temperature of the granular material without aiming at drying the granular material. Further, the heating device of the present invention may be a humidification heating device that performs heating and humidification by sending wet hot air to a material having a low moisture content. Further, the heating mechanism of the present invention may heat the casing of the heating hopper, or may have a heating plate arranged inside the heating hopper and in contact with the powder or granules.

  Further, in the above embodiment, the discharge destination of the granular material connected to the heating device is the injection molding device, but the discharge destination of the granular material is another molding device such as an extrusion molding device or an inflation molding device. It may be. Further, the discharge destination of the granular material is not limited to the molding apparatus, but may be another apparatus such as a polymerization apparatus.

  Further, the shape of the details of the heating device may be different from the shape shown in each drawing of the present application. In addition, the elements appearing in the above-described embodiments and the modified examples may be appropriately combined as long as no contradiction occurs.

REFERENCE SIGNS LIST 1 heating drying device 8 injection molding machine 9 resin pellet 20 heating hopper 24 lower sensor 25 upper sensor 30 heating mechanism 31 heating circulation line 33 heating blower 34 heater 35 outlet 40 supply mechanism 41 storage hopper 43 supply hopper 44 supply Circulation line 46 Supply blower 50 Discharge mechanism 51 Discharge pipe 52 Shutter 60 Control unit 201 Input port 202 Discharge port 231 Suction port

Claims (8)

A heating hopper for storing powder and granules inside,
A heating mechanism that heats the powder particles stored inside the heating hopper,
A supply mechanism for supplying the granular material from the upper part of the heating hopper into the heating hopper,
An outlet for discharging the powder and granules stored in the heating hopper from a lower portion of the heating hopper,
A control unit for controlling operations of the heating mechanism and the supply mechanism,
Has,
The control unit, from the empty state of the heating hopper, until the granular material in the heating hopper reaches a predetermined initial upper limit,
A supply step of continuously or intermittently supplying the granular material by the supply mechanism,
A standby step of performing heating by the heating mechanism while stopping the supply mechanism until a predetermined time has elapsed ;
There rows first supply step of repeating, storing the said powder or granular material into the heating hopper,
The heating device, wherein the predetermined time is a time longer than a time for sufficiently expanding the granular material in the heating hopper . A heating hopper for storing powder and granules inside,
  A heating mechanism that heats the powder particles stored inside the heating hopper,
  A supply mechanism for supplying the granular material from the upper part of the heating hopper into the heating hopper,
  An outlet for discharging the powder and granules stored in the heating hopper from a lower portion of the heating hopper,
  A control unit for controlling operations of the heating mechanism and the supply mechanism,
Has,
  The control unit, from the empty state of the heating hopper, until the granular material in the heating hopper reaches a predetermined initial upper limit,
    A supply step of continuously or intermittently supplying the granular material by the supply mechanism,
    A standby step of performing heating by the heating mechanism while stopping the supply mechanism,
Performing a first supply step of repeating the above, storing the granular material in the heating hopper,
  A heating device configured to heat the granular material to a predetermined temperature at which a bridge or blocking hardly occurs even when a weight is applied from above in the standby step. The heating device according to claim 1 or claim 2,
  The heating device, wherein in the supplying step, a first predetermined amount of the granular material, which is an amount that hardly causes bridge or blocking due to its own weight when heated, is supplied into the heating hopper. The heating device according to any one of claims 1 to 3, wherein
Inside the heating hopper, a level sensor for detecting the height of the powder and granules is provided,
The controller stops the first supply step and performs a second supply step when the granular material stored in the heating hopper reaches the initial upper limit amount,
The second supply step is a feedback control step of supplying the powder and granules to the heating hopper by the supply mechanism when it is determined that the powder and granules in the heating hopper are below the detection position of the level sensor. There is a heating device. The heating device according to any one of claims 1 to 4, wherein
The average supply speed of the granular material to the heating hopper by the supply mechanism is substantially the same as the average discharge speed of the granular material from the discharge port after the discharge of the granular material from the heating hopper is started. Is a heating device. The heating device according to any one of claims 1 to 5, wherein
The heating device, wherein the control unit dries the powder and granules by heating the powder and granules in the heating hopper by the heating mechanism. A method for controlling a heating device, comprising: a heating hopper provided with a heating mechanism; a supply mechanism for supplying the granular material from an upper portion of the heating hopper; and an outlet for discharging the granular material from a lower portion of the heating hopper. From the empty state of the heating hopper,
a step of introducing a) before Symbol powdery grains continuously or intermittently said heating hopper,
b) after the step a) , heating the powder in the heating hopper until a predetermined time elapses , while stopping the supply of the powder by the supply mechanism;
By repeating the above, the granular material is stored in the heating hopper ,
The method for controlling a heating device, wherein the predetermined time is a time longer than a time for sufficiently expanding the granular material in the heating hopper .   A method for controlling a heating device, comprising: a heating hopper provided with a heating mechanism; a supply mechanism for supplying the granular material from an upper portion of the heating hopper; and an outlet for discharging the granular material from a lower portion of the heating hopper. From the empty state of the heating hopper,
  A) a step of continuously or intermittently charging the powder or granules into the heating hopper;
  B) after the step A), heating the powder in the heating hopper while stopping the supply of the powder by the supply mechanism;
By repeating the above, the granular material is stored in the heating hopper,
  In the step (B), a method for controlling a heating device, wherein the granular material is heated to a predetermined temperature at which bridging or blocking hardly occurs even when a load is applied from above.

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