Granulation system

Abstract

To provide a granulation system that ensures stable pellet formation while preventing overload of driving means.SOLUTION: This granulation system 100 is a pellet granulation system, comprising: a granulater 1 that forms granular raw material into pellets by driving a motor 5; and a feeder 51 that feeds the granulater 1 with the granular raw material at a predetermined feed rate, the feeder 51 comprising a raw material charger 52, a raw material conveyor belt 53, a siever 54, and an input belt 55. A controller 61 is also included that controls the feed rate of the feeder 51 based on the load size on the motor 5.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a granulation system for forming powdered or granular raw materials such as compost into pellets. [Background technology]

[0002] Traditionally, in various fields such as timber, food, pharmaceuticals, and compost, powdered and granular raw materials have been formed into pellets. Generally, forming them into pellets offers advantages in terms of handling and transportation.

[0003] As a granulation apparatus for forming powdered or granular raw materials into pellets, an extrusion-type granulation apparatus is known. An extrusion-type granulation apparatus mainly comprises a cylindrical member with numerous through-holes and an extrusion member rotatably mounted within the cylindrical member. The through-holes penetrate from the inside to the outside of the cylinder and are generally formed in a cylindrical shape. After the powdered or granular raw material is fed into the cylindrical member, the extrusion member is rotated, causing the powdered or granular raw material to be pushed out through the through-holes. As the powdered or granular raw material passes through the through-holes, it is subjected to pressure and solidifies, forming pellets. In an extrusion-type granulation apparatus, rollers or extrusion blades are generally used as extrusion jigs.

[0004] For example, Patent Document 1 describes a compost granulation apparatus that employs rollers in the extrusion jig. When compost is used in powder form, it is easily affected by wind and difficult to spread evenly, so pelletizing it has the advantage of making it easier to spread. In addition, with pellets, the spread compost does not wash away all at once due to rain, but gradually seeps into the soil, which is considered preferable for the soil. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2007-137731 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Incidentally, a granulation system for forming powdered or granular raw materials into pellets mainly comprises a granulation device, a supply device for supplying the powdered or granular raw materials to the granulation device, and a discharge device for discharging the pellets formed by the granulation device. In such a granulation system, the powdered or granular raw materials are supplied to the granulation device at a predetermined supply speed by a conveyor or the like, and the formed pellets are discharged from the granulation device and transported.

[0007] Here, the resistance to rotation of extrusion members and other components varies depending on the moisture content of the granular raw material. For example, when the moisture content of the granular raw material is low, the resistance to rotation tends to be higher compared to when it is high. Therefore, the load on the motor (driving means) of the granulation apparatus differs depending on the moisture content of the granular raw material, and as a result, the motor may become overloaded. In conventional granulation systems, for example, motor overload is managed by a thermal switch. That is, if the motor temperature rises excessively, the electromagnetic contactor is activated to interrupt the electrical circuit and prevent the motor from burning out. However, when the thermal switch is activated, it is necessary to adjust the configuration of the granulation apparatus (for example, the position of the extrusion member) to resolve the motor overload, which could lead to a decrease in work efficiency.

[0008] This invention has been made in view of these circumstances, and aims to provide a granulation system that can stably perform pelletization while preventing overload of the driving means. [Means for solving the problem]

[0009] The granulation system of the present invention is a pellet granulation system comprising a granulation device that forms powdered raw material into pellets by driving a drive means, and a supply device that supplies powdered raw material to the granulation device at a predetermined supply speed, wherein the granulation system has a control unit that controls the supply speed of the supply device based on the magnitude of the load applied to the drive means.

[0010] The above-described supply device comprises a sieving device that sieves the material to be processed and discharges it at a predetermined discharge rate, a first conveying means for conveying the material to be processed to the sieving device, and a second conveying means for conveying the processed material sieved by the sieving device as a powder or granular raw material to the granulation device, and the control unit controls the conveying speed of the second conveying means as the supply rate of the supply device.

[0011] The control unit is characterized in that, in conjunction with the control of the transport speed of the second transport means, it also controls the transport speed of the first transport means and the discharge speed of the sieving device.

[0012] The control unit is characterized in that it reduces the supply speed of the supply device when the load on the drive means exceeds a first threshold, and stops the supply of powdered or granular raw material by the supply device when the load on the drive means exceeds a second threshold (which is greater than the first threshold).

[0013] The control unit is characterized by controlling the supply speed of the supply device based on the current value flowing through the drive means as a load applied to the drive means.

[0014] The granulation apparatus comprises a cylindrical member having numerous through holes, a rotating shaft that rotates by the drive of the drive means, an extrusion member connected to the rotating shaft and rotatably mounted inside the cylindrical member, and a cutting member having one or more cutter sections that rotate on the outside of the cylindrical member and cut the powdered raw material extruded from the through holes, wherein the drive means is a single drive means in the granulation apparatus and rotates both the extrusion member and the cutting member.

[0015] The lid member of the granulation section of the granulation apparatus described above has an inlet for inflatable raw materials, and a part of the lid member is configured to be openable and closable so that the inside of the granulation section can be viewed while the granular raw materials are being introduced. [Effects of the Invention]

[0016] The granulation system of the present invention comprises a granulation apparatus that forms powdered raw material into pellets by driving a drive means, and a supply device that supplies the powdered raw material to the granulation apparatus at a predetermined supply speed. The granulation system has a control unit that controls the supply speed of the supply device based on the magnitude of the load on the drive means. For example, if the load on the drive means is large, the supply speed of the powdered raw material can be reduced, preventing the drive means of the granulation apparatus from becoming overloaded. As a result, the granulation system of the present invention can stably perform pelletization while preventing overloading of the drive means.

[0017] In granulation systems, a system is employed in which the sieved material is directly supplied to the granulation device as powdered or granular raw material. In such a configuration, the control unit controls the conveying speed of the first conveying means and the discharge speed of the sieving device in conjunction with the conveying speed of the second conveying means. This allows for control of the supply speed of powdered or granular raw material to the granulation device, suppresses localized uneven distribution of the raw material within the supply device, and leads to a stable supply of powdered or granular raw material.

[0018] The above-described granulation apparatus is an extrusion-type granulation apparatus that uses an extrusion member that rotates within a cylindrical member, and is equipped with a cutting member having one or more cutter sections for cutting the granular raw material extruded from through holes. The driving means is a single driving means in the granulation apparatus, and since it rotates both the extrusion member and the cutting member, it becomes easier to grasp the magnitude of the load on the driving means. As a result, it becomes easier to control the supply speed based on the magnitude of the load more accurately. In addition, a separate driving means for rotating the cutting member is not required, which can lead to space savings and cost reductions in the granulation apparatus.

[0019] In the lid member of the granulation section of the granulation apparatus, an input port for powdery and granular raw material is formed, and a part of the lid member is configured to be openable and closable so that the inside of the granulation section can be visually checked while the powdery and granular raw material is being input. Therefore, for example, when the load applied to the driving means increases, the state inside the granulation section can be checked while continuing granulation. Further, maintenance and the like inside the granulation section can be performed without removing the lid member itself, and work efficiency can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] [Figure 1] It is a schematic diagram of an example of the granulation system of the present invention. [Figure 2] It is a perspective view of an example of a granulation apparatus in the granulation system of the present invention. [Figure 3] It is a schematic cross-sectional view of the granulation apparatus of Fig. 2. [Figure 4] It is a plan view of the granulation apparatus of Fig. 2. [Figure 5] It is a side view of a cutting member. [Figure 6] It is a configuration diagram showing a control unit and each apparatus in the granulation system of the present invention. [Figure 7] It is a timing chart showing an example of control of a supply speed by the control unit. [Figure 8] It is a diagram for explaining an adjustment mechanism that adjusts a gap distance. [Figure 9] It is a plan view of a lid member in the granulation apparatus of the present invention. [Figure 10] It is a cross-sectional view of a lid member in the granulation apparatus of the present invention. MODE FOR CARRYING OUT THE INVENTION

[0021] An example of the granulation system of the present invention will be described with reference to Figure 1. Figure 1 shows a schematic plan view of the granulation system. The granulation system 100 shown in Figure 1 is a pellet granulation system that granulates powdery raw materials such as compost into pellets. The granulation system 100 basically comprises a granulation device 1 that forms powdery raw materials into pellets, a supply device 51 that supplies powdery raw materials to the granulation device 1 at a predetermined supply rate, and a discharge device 71 that discharges the pellets formed by the granulation device 1. In the granulation system 100, powdery raw materials are automatically supplied from the supply device 51 to the granulation device 1, and pellets are discharged from the granulation device 1 and continuously discharged by the discharge device 71.

[0022] In Figure 1, the supply device 51 includes a raw material input device 52, a raw material conveying belt 53 that conveys the raw material (powdered or granular raw material before sieving) input to the raw material input device 52 to the sieving device 54, the sieving device 54, and an input belt 55 that conveys the processed material (powdered or granular raw material) sieved by the sieving device 54 to the granulation device 1. The raw material conveying belt 53 corresponds to the "first conveying device" of the present invention, and the input belt 55 corresponds to the "second conveying device" of the present invention.

[0023] The raw materials fed into the raw material input device 52 are transported to the sieving device 54 by the raw material conveyor belt 53, where they are sieved. In Figure 1, the sieving device 54 is a rotary sieving device. This device is equipped with a rotary sieve, such as a cylindrical one, into which the material to be processed is introduced. The rotary sieve is rotated by a driving means such as a motor, causing the material introduced inside to fall out through the mesh of the rotary sieve for sieving. In a rotary sieving device, for example, a screw conveyor is attached as a transfer means, and the material to be processed is transferred from the device inlet to the device outlet by the rotation of the screw conveyor. Note that the sieving device 54 is not limited to a rotary sieving device, as it can be any device capable of sieving the material to be processed. The sieved material (the material that remains inside without passing through the mesh of the sieve and is discharged from the device outlet) is transported as granular raw material to the granulation device 1 by the input belt 55.

[0024] The granulation apparatus 1 includes a granulation unit 3 for granulating powdered raw material into pellets, and a motor 5 (driving means) for driving the granulation unit 3. The motor 5 is, for example, an AC motor controlled by an inverter. An inlet 3c for the powdered raw material is formed at the top of the granulation unit 3, and the powdered raw material is fed into the inlet 3c from the end of the feeding belt 55.

[0025] Next, the detailed configuration of the granulation apparatus 1 will be explained using Figures 2 to 4. Figure 2 is an overall perspective view showing an example of a granulation apparatus. The granulation apparatus shown in Figure 2 is an extrusion-type granulation apparatus. As shown in Figure 2, the granulation apparatus 1 has a base 2 that serves as the base, a granulation unit 3 installed on the base 2, a chute 4 that slopes diagonally downward from the granulation unit 3, and a motor 5 that drives the granulation unit 3. A pulley cover 20 is provided below the motor 5. The granulation unit 3 is substantially cylindrical in shape, and its outer surface is covered with a cylindrical cover 3a, on which a lid member 3b is installed. An input port 3c for powdered raw material is formed on the upper part of the lid member 3b. As will be described later, a suction port may also be provided on the lid member 3b. The pellets granulated in the granulation unit 3 are removed from the chute 4. The removed pellets are then discharged by a discharge device (e.g., a discharge conveyor).

[0026] The granulation apparatus will be described in detail using Figures 3 and 4. Figure 3 is a schematic cross-sectional view of the granulation apparatus with the cover and lid removed, and Figure 4 is a plan view of the granulation section in that state. As shown in Figure 3, the granulation section 3 mainly comprises a cylindrical member 6, a rotating shaft 11, an extrusion member 21 connected to the rotating shaft 11 and rotatably mounted within the cylindrical member, and a cutting member 31 that rotates integrally with the extrusion member 21. The motor 5 is a single driving means in the granulation apparatus 1 and rotates both the extrusion member 21 and the cutting member 31. By using a single driving means, the magnitude of the load on the motor 5 can be more easily grasped in the control by the control unit described later. Note that, due to the positional relationship between the extrusion member 21 and the cutting member 31 (see Figure 4), the cutting member 31 is omitted in Figure 3, and the position of the cutter part when rotated is indicated by a dotted line.

[0027] In Figure 3, the cylindrical member 6 has a die 7 and a side wall member 9 attached to the upper part of the die 7. The die 7 is detachably attached to the die holder 10 which forms the bottom of the granulation section 3. The extrusion member 21 is housed in a bottomed cylindrical space surrounded by the cylindrical member 6 and the die holder 10. The die 7 has numerous through holes 8 that penetrate the inside and outside of the cylinder around its entire circumference. The rotation of the extrusion member 21 pushes the granular raw material outward through the through holes 8, forming it into pellets. The cylindrical member 6 may be composed of a single piece in which the die and the side wall member are integrally formed. In that case, through holes are provided at the bottom of the cylindrical member.

[0028] The rotating shaft 11 rotates when the rotational force of the motor 5 is transmitted via the power transmission mechanism 12. The power transmission mechanism 12 includes a small pulley 14 connected to the base end of the drive shaft 13, a large pulley 15, a belt 16 stretched between the small pulley 14 and the large pulley 15, a small gear 17, a gear shaft 18 connecting the large pulley 15 and the small gear 17, and a large gear 19 that meshes with the small gear 17. The large gear 19 is connected to the base end of the rotating shaft 11, and the rotational force of the motor 5 is transmitted to the rotating shaft 11 by each pulley and each gear. The rotating shaft 11 is positioned vertically and is rotatably supported by bearings within the die holder.

[0029] As shown in Figures 3 and 4, the extrusion member 21 has two pressure rollers 22, 22, which are arranged rotationally symmetrically around the rotation axis 11. Specifically, the extrusion member 21 has a support plate 23 that is roughly rectangular in plan view, and this support plate 23 is connected to the tip of the rotation axis 11 by a connector 24. Shaft holes are provided on both sides of the extension of the support plate 23, and shaft members 25 are inserted into each shaft hole. The shaft member 25 has a roller shaft 25a that supports the pressure rollers 22 and an eccentric shaft 25b that is inserted into the shaft hole of the support plate 23. The eccentric shaft 25b is formed integrally with the roller shaft 25a and is eccentric with respect to the roller shaft 25a, but the adjustment mechanism based on this configuration will be described later.

[0030] The pressure roller 22 is rotatably supported on the shaft member 25 by a bearing 26. The pressure roller 22 revolves around the rotation axis P as the rotation of the rotation shaft 11 and rotates on its own axis Q. In addition, multiple grooves (not shown) are formed on the outer surface of the pressure roller 22 along the axial direction, making it easier for it to rotate in conjunction with the movement of the powdered raw material. Although two pressure rollers are provided in Figures 3 and 4, the number of pressure rollers may be one or three or more. When multiple pressure rollers are provided, it is preferable to make the angular spacing between adjacent rollers equal (180° intervals in Figures 3 and 4).

[0031] The pressure rollers 22 are positioned with a predetermined gap (for example, 1 mm) between them and the inner circumferential surface of the die 7. The granular material introduced into the cylindrical member is fed into the gap between the pressure rollers 22 and the die 7 by the rotation of the extrusion member 21. The fed granular material is pushed into the through-hole 8 of the die 7 by the rotation of the pressure rollers 22 and solidifies under pressure. The solidified granular material is then pushed out of the die 7 through the through-hole 8. In this way, the pressure rollers 22 function as an extrusion jig that pushes the granular material outwards. Note that although rollers are used as the extrusion jig in Figures 3 and 4, extrusion blades may be used instead of rollers.

[0032] The rod-shaped granular raw material extruded through the through-hole is cut by a cutter that rotates around the outside of a cylindrical member. This cutting member having a cutter will be explained with reference to Figure 5. Figure 5 is a side view of the cutting member.

[0033] In Figure 5, the cutting member 31 is formed symmetrically with respect to the center line and has two cutter sections 35. The cutting member 31 has a support plate 32, which is roughly rectangular in plan view, positioned at its center and connected to the extrusion member by a connector 33. Alternatively, the cutting member 31 may be directly connected to the rotation axis. One end of a roughly U-shaped connecting plate 34 is connected to each end of the support plate 32. The connecting plate 34 is shaped to overlap the side wall member so as not to interfere with the aforementioned side wall member. The other end of the connecting plate 34 is connected to the cutter section 35 by a connector 36. The cutter section 35 is mounted so as to extend vertically downward.

[0034] The cutter section 35 is made of a metal plate having a predetermined thickness. The lower part 35b (including the cutting surface 35c) facing the outer surface of the die is wider in the radial direction as viewed from the center of rotation than the upper part 35a which is connected by a connector 36. The cutting surface 35c facing the outer surface of the die is arranged at a constant distance from the outer surface of the die. In addition, reinforcing ribs 37 are provided vertically along the radially outer side of the cutter section 35. The ribs 37 are provided, for example, so as to be upright on both sides of the cutter section 35. As shown in Figure 5, the cutter section 35 is fixed only at the top and the bottom is a free end, so the ribs 37 help to suppress deformation of the cutter section 35.

[0035] Furthermore, the lower end surface of the cutter section 35 has a stepped surface 35d with a recessed inner diameter. As shown in Figure 3, a connector protrudes from the collection section (part of the upper surface of the die holder 10) located outside the die 7 from which the cut pellets fall. Therefore, by providing the stepped surface 35d on the lower end surface of the cutter section 35, interference with such a connector can be prevented. On the other hand, by positioning the outer diameter side of the lower end surface as close as possible to the collection section, the cut pellets can be easily collected.

[0036] Here, the installation of the cutting member will be explained using Figure 4. As shown in Figure 4, the cutting member 31 is connected to the support plate 23 of the extrusion member 21 via the support plate 32 by a connector 33. The cutting member 31 is connected so that its center coincides with the axis of rotation P. In this case, as shown in Figure 4, it is preferable to fix the cutter sections 35, 35 so that they rotate in a different phase from the pressure rollers 22, 22. In Figure 4, the cutter sections 35, 35 and the pressure rollers 22, 22 are positioned with a phase difference of 90° each. In other words, each cutter section and each pressure roller are fixed in different positions in the radial direction. In this configuration, the granular material extruded by the pressure rollers 22, 22 is cut by the cutter sections 35, 35 which rotate immediately afterward. By shifting the phase of the cutter section 35 and the pressure rollers 22, and configuring the system to cut the granular material quickly after extrusion, it becomes easier to make the pellet shape uniform. The cut pellets are removed from the chute 4.

[0037] As shown in Figure 1, the granulation system 100 is an automated system from supplying to the granulation device 1 to unloading. In this configuration, the conveying speed V3 for transporting the granular raw material to the granulation device 1 is set so that the granular raw material is supplied to the granulation device 1 without excess or deficiency. For example, in the configuration shown in Figure 1, the conveying speed V1 of the raw material conveying belt 53, the discharge speed V2 of the sieving device 54, and the conveying speed V3 of the input belt 55 are set according to the processing capacity of the granulation device 1. In addition, the granulation device 1 is set to an arbitrary rotational speed by an inverter-controlled motor 5.

[0038] Thus, the granulation system is configured with set operating speeds for various devices. However, the moisture content and properties of the granular raw materials supplied to the granulation device are not uniform, and as a result the load on the granulation device's motor differs, the motor may become overloaded.

[0039] In contrast, the granulation system 100 of the present invention has a control unit 61 that controls the supply speed of the supply device 51 based on the magnitude of the load on the motor 5. The operation of the control unit 61 will be explained with reference to Figures 6 and 7.

[0040] In Figure 6, the control unit 61 is communicated with the load detection unit 5a, which detects the magnitude of the load on the motor 5; the drive unit 53a for the raw material conveying belt 53; the drive unit 54a for the sieving device 54; and the drive unit 55a for the input belt 55.

[0041] The control unit 61 is a device that controls the supply speed of the supply device 51, and is mainly composed of a microcomputer consisting of a well-known CPU, ROM, RAM, etc. In Figure 6, the control unit 61 controls the transport speed V3 of the input belt 55 by transmitting a drive instruction to at least the drive unit 55a of the input belt 55. In the present invention, the indicator that shows the load on the motor 5 is not particularly limited, but for example, the current value flowing through the motor 5 can be used. For example, if the motor 5 is an AC motor, the instantaneous value of the AC current can be used, and if it is a DC motor, the DC current value can be used.

[0042] In the following section, we will explain the case where the current value is used as the load applied to the motor. In this case, the load detection unit 5a is a current sensor, and the larger the detected current value, the larger the load, and the smaller the detected current value, the smaller the load.

[0043] In FIG. 6, the control unit 61 controls the conveying speed V3 of the feeding belt 55 as the feeding speed of the supply device 51 based on the current value A detected by the current sensor. In this case, the amount of the powdery or granular raw material supplied to the granulator 1 per unit area on the feeding belt 55 is substantially constant. Specifically, for the control, when the acquired current value A is equal to or less than the first threshold value Th1, the conveying speed V3 is maintained at a predetermined speed, and when the acquired current value A exceeds the first threshold value Th1, the conveying speed V3 is set to a speed lower than the predetermined speed. The speed lower than the predetermined speed may be a fixed value or a variable value that changes in accordance with the current value A. For example, in the case of a fixed value, the speed is 0.2 to 0.8 times the predetermined speed before the change. Further, in the case of a variable value, for example, the speed is set to decrease as the current value A increases. An example of detailed control will be described with reference to FIG. 7.

[0044] As described above, when the current value A exceeds the first threshold value (when the load on the motor exceeds a predetermined value), by suppressing the supply speed of the powdery or granular raw material to a low level, it is possible to prevent excessive supply of the powdery or granular raw material to the granulator whose load is increasing.

[0045] Furthermore, when the acquired current value A exceeds a second threshold value Th2 (Th1 < Th2), the conveying speed V3 may be set to zero, that is, the supply of the powdery or granular raw material may be stopped. This makes it easier to further reduce the load applied to the motor 5. Further, after the supply is stopped, when the load applied to the motor 5 decreases and the current value A becomes equal to or less than the second threshold value, the conveying of the feeding belt 55 may be resumed to start the supply of the powdery or granular raw material. Note that the threshold value for resumption is not limited to Th2, and may be set to a value smaller than Th2 (for example, Th1).

[0046] The method for controlling the transport speed V3 of the input belt 55 in the control unit 61 is not limited to the method described above. For example, in addition to thresholds Th1 and Th2, other thresholds may be set to gradually reduce the transport speed V3 of the input belt 55. The thresholds Th1, Th2, etc. are set appropriately according to the motor specifications, etc., but it is preferable to set them to a value smaller than the current value in an overload condition that would cause the thermal switch to activate.

[0047] In Figure 6, it is preferable that the control unit 61 controls the conveying speed V3 of the input belt 55, as well as the conveying speed V1 of the raw material conveying belt 53 and the discharge speed V2 of the sieving device 54. In this case, the control unit 61 controls the conveying speed V1 of the raw material conveying belt 53 by transmitting a drive instruction to the drive unit 53a of the raw material conveying belt 53, and controls the discharge speed V2 of the sieving device 54 by transmitting a drive instruction to the drive unit 54a (e.g., the transfer means) of the sieving device 54. The discharge speed V2 of the sieving device 54 is the speed at which the processed material is discharged from the device, and can be adjusted by controlling, for example, the transfer speed of the transfer means.

[0048] Specifically, it is preferable that the control unit 61 reduces (or stops) the conveying speed V1 of the raw material conveying belt 53 and the discharge speed V2 of the sieving device 54 in conjunction with reducing (or stopping) the conveying speed V3. By controlling the other driving means of the supply device 51 (raw material conveying belt 53 and sieving device 54) in addition to the conveying speed V3 of the input belt 55, it is possible to prevent localized accumulation of raw materials within the supply device and maintain a good balance in the supply of powdered and granular raw materials. The manner in which the conveying speed V1 of the raw material conveying belt 53 and the discharge speed V2 of the sieving device 54 are reduced or stopped can be appropriately adopted from the various modes described for the input belt 55.

[0049] Figure 7 is a timing chart showing an example of supply speed control by the control unit. It shows the time progression of the transport speed V1, discharge speed V2, transport speed V3 of each drive means in the supply device, and the current value A of the motor of the granulation device.

[0050] As shown in Fig. 7, when the current value A of the motor is equal to or less than the threshold Th1, the conveyance speed V1 is set to V A , the discharge speed V2 is set to V C , and the feeding speed V3 is set to V E . When the current value A exceeds the threshold Th1 at time t1, the control unit reduces the conveyance speed V3. At the same time, it also reduces the conveyance speed V1 and the discharge speed V2. Specifically, the conveyance speed V1 is set to V B , the discharge speed V2 is set to V D , and the conveyance speed V3 is set to V F . In this control example, each speed after the change is set to a fixed value.

[0051] Then, when the current value A of the motor further increases and exceeds the threshold Th2 at time t2, the control unit stops the supply by the feeding belt (conveyance speed V3=0). At the same time, it also stops the driving of the raw material conveyance belt and the driving of the rotary sieving device (conveyance speed V1=0, discharge speed V2=0).

[0052] Thereafter, the current value A of the motor decreases due to the stop of the supply device, and when the current value A becomes equal to or less than the threshold Th2, the supply of the powdery and granular raw material is resumed. In this control example, each speed after resumption is set respectively according to the mode of Th1<A≦Th2. Specifically, the conveyance speed V1 is set to V B , the discharge speed V2 is set to V D , and the conveyance speed V3 is set to V F .

[0053] Next, various configurations of the granulating device will be described. It is preferable that the granulating device has an adjustment mechanism for adjusting the gap distance between the pressure roller and the inner peripheral surface of the die. This adjustment mechanism will be described with reference to Fig. 8. As shown in Fig. 8, in the shaft member 25, the eccentric shaft 25b is eccentric with respect to the roller shaft 25a. The eccentric shaft 25b penetrates the support plate 23 and is fitted and fixed to an adjustment pulley 27 provided on the upper surface of the support plate 23. The adjustment pulley 27 has a lever portion 27a. By rotating this lever portion 27a in the direction of the arrow, the position of the pressure roller 22 is changed, and the gap distance between the pressure roller 22 and the inner peripheral surface 7a can be adjusted.

[0054] Furthermore, the position of the lever portion 27a is fixed by a pair of fixing means provided on the support plate 23. Each fixing means comprises a fixing nut 28 fixed on the support plate, an adjustment screw 29 screwed into the screw hole of the fixing nut 28, and a stop nut 30 located on the outside of the fixing nut 28. By rotating the adjustment screws 29, 29 respectively, the amount of protrusion relative to the fixing nuts 28, 28 is adjusted, and the lever portion 27a is clamped from both sides at the desired position. This allows the gap distance between the pressure roller 22 and the inner circumferential surface 7a to be adjusted, while stably maintaining the adjusted state. With this configuration, for example, it becomes easy to adjust the position of the pressure roller when reducing the load on the motor.

[0055] Furthermore, the lid member in the granulation apparatus of the present invention is not limited to the form shown in Figure 2. For example, the lid member may have a structure in which at least a portion of the top surface can be opened and closed. Figures 9 and 10 show examples of such lid members.

[0056] As shown in Figure 9, the lid member 41 has two divided lids 42 and 45 that are attached to be openable and closable. The divided lids 42 and 45 are divided by a dividing line L in the diametrical direction, and the input openings 42a and 45a are also divided by this dividing line. In this case, the input opening 42a is integrally formed with the divided lid 42, and the input opening 45a is integrally formed with the divided lid 45. The divided lid 42 is attached to the fixed lid 43 via a plurality of (three in Figure 9) hinges 44, and the divided lid 45 is attached to the fixed lid 46 via a plurality of (two in Figure 9) hinges 47. The lid member 41 itself is removable from the granulation unit.

[0057] According to the configuration in Figure 9, the divided lids 42 and 45 can change from a closed state to an open state in a double-door manner, and further, they can change from an open state to a closed state. In this way, by making a part of the top surface of the lid member openable and closable, maintenance of the granulation section can be performed without removing the lid member itself. In addition, a part of the lid member 41 is configured to be openable and closable so that the inside of the granulation section can be viewed while powdered raw material is being fed in. For example, if the load on the motor becomes large, the condition inside the granulation section can be checked while granulation continues. As a result, work efficiency can be improved. Note that the structure in which at least a part of the top surface of the lid member is openable and closable is not limited to Figure 9.

[0058] Furthermore, as shown in Figure 9, the lid member 41 may be provided with a suction port 48 that can be connected to a dust collector. In Figure 9, the fixed lid 46 is provided with three suction ports 48. The suction ports 48 can communicate with the space inside the granulation section (see Figure 10), and by connecting a dust collector, dust generated in the granulation section can be collected. This suppresses the scattering of dust during granulation and improves the deterioration of the working environment and other problems. Note that the number of suction ports can be as one or as appropriate.

[0059] The granular raw materials used in the granulation system of the present invention can include wood chips, pharmaceutical raw materials, food raw materials, compost, and the like. The moisture content of the granular raw materials can be, for example, 10% to 40% by mass, or 15% to 30% by mass. The shape of the granular raw materials can include not only powder and granules, but also lumps.

[0060] Compost used as a granular raw material can be obtained using equipment that can ferment and compost organic waste, such as livestock manure discharged from livestock farms or food waste discharged from food processing plants. One known type of equipment for such composting is a sealed vertical composting device (compo) that utilizes the fermentation action of microorganisms. This compo has a cylindrical vertical tank shape and performs drying and fermentation while forcibly aerating the organic waste placed inside the sealed container. Furthermore, compost raw materials are added sequentially and compost is discharged, allowing for continuous composting. The granulation system of the present invention can be used in combination with existing technologies for composting waste, and can reduce the amount of waste that needs to be incinerated.

[0061] The granulation system of the present invention has been described above, but the granulation system of the present invention is not limited to the configurations shown in the figures above.

[0062] For example, in Figure 6, the supply device 51 is configured to include a raw material input device 52, a raw material conveying belt 53, a sieving device 54, and an input belt 55, but it is not limited to this configuration. For example, the sieving device may be omitted, and a granulation system using pre-sieved powdered or granular raw materials may be used. In this case, the supply device may consist of an input device for inputting pre-sieved powdered or granular raw materials, and a conveying means for transporting the powdered or granular raw materials from the input device to the granulation device.

[0063] Furthermore, the conveying means for transporting powdered or granular raw materials to the granulation device is not limited to a belt type. In this case, the control unit controls the supply speed of the supply device by controlling factors other than the conveying speed of the belt. [Industrial applicability]

[0064] The granulation system of the present invention can stably perform pelletization while preventing overload of the driving means, and therefore can be applied, for example, to a mass production process for compost pellets. [Explanation of symbols]

[0065] 1 Granulation equipment 2 bases 3. Granulation section 4 shots 5. Motor (driving means) 6. Cylindrical member 7 dice 8 Through holes 8a Inner passage 8b Passageway 8c Outside passage 9 Side wall member 10 Dice Holder 11 Rotation axis 12 Power transmission mechanism 13 Drive shaft 14 Small Pulley 15 Large Pulley 16 belts 17 Small gears 18 Gear shaft 19 Large gear 20 Pulley Cover 21 Extruded member 22 Pressure roller (extrusion jig) 23 Support plate 24 Connectors 25 Shaft member 25a Roller shaft 25b eccentric shaft 26 bearings 27 Adjustable pulley 28 Fixing nuts 29 Adjustment screw 30 Set nuts 31 Cutting member 32 Support plate 33 Connectors 34 Connecting plate 35 Cutter section 36 Connectors 37 Ribs 41 Lid member 42 split lid 43 Fixed lid 44 Hinge section 45 split lid 46 Fixed lid 47 Hinge section 48 Suction port 51 Feeding device 52 Raw material input device 53 Raw material conveying belt 54 Sieving device 55 Input belt 61 Control Unit 71 Unloading device 100 Granulation System

Claims

1. A pellet granulation system, The system comprises a granulation device that forms powdered or granular raw materials into pellets by driving a drive means, and a supply device that supplies powdered or granular raw materials to the granulation device at a predetermined supply speed. The granulation system is characterized in that it has a control unit that controls the supply speed of the supply device based on the magnitude of the load on the driving means, and the control unit reduces the supply speed of the supply device when the magnitude of the load on the driving means exceeds a first threshold, and stops the supply of granular raw material by the supply device when the magnitude of the load on the driving means exceeds a second threshold (greater than the first threshold).

2. The supply device comprises a sieving device that screens the material to be processed and discharges it at a predetermined discharge rate, a first conveying means for transporting the material to be processed to the sieving device, and a second conveying means for transporting the processed material screened by the sieving device as a powder or granular raw material to the granulation device. The granulation system according to claim 1, characterized in that the control unit controls the transport speed of the second transport means as the supply speed of the supply device.

3. The granulation system according to claim 2, characterized in that the control unit controls the transport speed of the first transport means and the discharge speed of the sieving device in conjunction with the control of the transport speed of the second transport means.

4. The granulation system according to claim 1 or 2, characterized in that the control unit controls the supply speed of the supply device based on the current value flowing to the drive means as a load applied to the drive means.

5. The granulation apparatus comprises a cylindrical member having numerous through holes, a rotating shaft that rotates by the drive of the driving means, an extrusion member connected to the rotating shaft and rotatably mounted inside the cylindrical member, and a cutting member that rotates on the outside of the cylindrical member and has one or more cutter sections for cutting the powdered raw material extruded from the through holes. The granulation system according to claim 1 or 2, characterized in that the driving means is a single driving means in the granulation apparatus, and rotates the extrusion member and the cutting member.

6. The granulation system according to claim 1 or 2, characterized in that the lid member of the granulation section of the granulation apparatus has an opening for inputting powdered or granular raw materials, and a part of the lid member is configured to be openable and closable so that the inside of the granulation section can be viewed while powdered or granular raw materials are being input.

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