Air purge nozzle, powder and granular material processing apparatus, and air purge method

Abstract

To provide an air purge nozzle which can effectively clean particulate matters from an object and reduce air consumption to achieve energy saving, and to a particulate matter processing device and an air purge method.SOLUTION: A nozzle body of an air purge nozzle is connected with an air supply line which supplies air to the nozzle body. The nozzle body has a first pipe part 92 and a second pipe part. The first pipe part 92 extends rearward parallel to a right flat wall surface 75 of a mixing drum. The second pipe part bends or curves from the first pipe part 92 at a right angle and extends to the left side parallel to a bottom surface 71 of the mixing drum. Air is discharged from a first discharge port 94 formed at the first pipe part 92 to the flat wall surface 75 and air is intermittently discharged from a second discharge port 95 formed at the second pipe part to the bottom surface 71.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an air purge nozzle and an air purge method for purging powder and granular materials with air, and a powder and granular material processing apparatus including the air purge nozzle.

Background Art

[0002] For example, in the manufacturing process of plastic products, after the respective dosages of powder and granular materials such as plastic pellets, pulverized materials, and additives that are the raw materials of plastic products are mixed, the mixed powder and granular materials of multiple types are supplied to a molding machine.

[0003] Specifically, multiple types of powder and granular materials are sequentially put into a weighing hopper, and their dosages are weighed in the weighing hopper. The powder and granular materials weighed to each dosage are put into a mixing drum and mixed in the mixing drum. Then, the mixed powder and granular materials are transported from the mixing drum to a loader hopper and fed into the molding machine from the loader hopper.

[0004] Since plastic pellets and the like are dielectrics, they are strongly charged with static electricity and tend to adhere to the inner surfaces of containers such as mixing drums and loader hoppers. When powder and granular materials adhere to the inner surface of the container, the adhered powder and granular materials are separated from other powder and granular materials. Further, after the raw materials are discharged from the container, if powder and granular materials remain adhered to the inner surface of the container, variations occur in the amount and mixing ratio of the powder and granular materials fed into the molding machine depending on the remaining amount.

[0005] In order to prevent the adhesion of powder and granular materials to the inner surface of the container and the like, it has been proposed to provide an ionizer (static eliminator) for removing static electricity (see, for example, Patent Document 1). However, the ionizer is expensive, and it takes time to remove static electricity by the ionizer.

[0006] Also, it is conceivable to perform surface treatment for preventing the adhesion of powder and granular materials to the inner surface of the container and the like. However, since the surface treatment has material dependence, it is difficult to take a measure independent of the material.

[0007] Therefore, a configuration has been proposed in which air is ejected from an air nozzle to blow off the powder particles adhering to the object by air, thereby cleaning (removing) the powder particles from the object (see, for example, Patent Documents 2 and 3). This air purge configuration is inexpensive and has little material dependency.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0009] However, depending on the structure (shape) of the object, it may be difficult to sufficiently clean the powder particles from the object. If a mechanism for moving the air nozzle is provided corresponding to the structure of the object, mechanical parts for driving are arranged in the container in contact with the powder particles, so there is a risk of foreign matter mixing into the powder particles, and the cost also increases. If the amount of air ejected from the air nozzle is increased to sufficiently remove the adhering powder particles, the energy loss becomes large.

[0010] An object of the present invention is to provide an air purge nozzle and a powder particle processing apparatus that can effectively clean powder particles from an object.

[0011] Another object of the present invention is to provide an air purge method that can effectively clean powder particles from an object and achieve energy saving by suppressing air consumption.

Means for Solving the Problems

[0012] To achieve the above object, an air purge nozzle according to one aspect of the present invention is an air purge nozzle for cleaning particulate matter adhering to an object with air, and includes a nozzle body and an air supply line connected to the nozzle body for supplying air to the nozzle body. The nozzle body is formed in a tubular shape having a first pipe portion extending substantially parallel to a first wall surface of the object and a second pipe portion extending substantially parallel to a second wall surface intersecting the first wall surface of the object. A first discharge port for discharging air toward the first wall surface is formed in the first pipe portion, and a second discharge port for discharging air toward the second wall surface is formed in the second pipe portion.

[0013] According to this configuration, an air supply line for supplying air to the nozzle body is connected to the nozzle body. The nozzle body has a first pipe portion and a second pipe portion. The first pipe portion extends substantially parallel to the first wall surface of the object. The second pipe portion extends substantially parallel to a second wall surface intersecting the first wall surface of the object. Then, air is discharged from the first discharge port formed in the first pipe portion toward the first wall surface, and air is discharged from the second discharge port formed in the second pipe portion toward the second wall surface. Thereby, even if the object has a structure having a first wall surface and a second wall surface intersecting therewith, the particulate matter adhering to the first wall surface and the second wall surface can be cleaned with air. Also, the particulate matter can be cleaned with air from the corner between the first wall surface and the second wall surface. Therefore, the particulate matter can be effectively cleaned from the object.

[0014] The first discharge port may be provided so as to discharge air in a direction inclined at a first angle with respect to the first wall surface such that the air has a downward velocity component along the first wall surface, and the second discharge port may be provided so as to discharge air in a direction inclined at a second angle with respect to the second wall surface such that the air has a downward velocity component along the second wall surface.

[0015] With this configuration, the air discharged from the first discharge port collides with the granular material adhering to the first wall surface and then flows downward along the first wall surface. Also, the air discharged from the second discharge port collides with the granular material adhering to the second wall surface and then flows downward along the second wall surface. Therefore, the granular material blown off from the first wall surface and the second wall surface by the air can be carried by the air and made to flow downward. As a result, the granular material can be more effectively cleaned from the object.

[0016] The first angle and the second angle may each be set within a range of 30° or more and 80° or less.

[0017] The first discharge port may be provided to discharge air in a direction perpendicular to the first wall surface, and the second discharge port may be provided to discharge air in a direction perpendicular to the second wall surface.

[0018] The air supply line may be configured to include an air flow pipe through which air from an air supply source flows, a valve that controls the flow of air in the air flow pipe, and an air storage unit that is interposed upstream of the valve in the air flow direction in the air flow pipe and stores air in a state where the flow of air is blocked by the valve.

[0019] In this configuration, when the valve is closed, air accumulates in the air storage unit and the internal pressure of the air storage unit increases. Then, when the valve is opened, the internal pressure of the air storage unit is instantaneously released and air is ejected from the first discharge port and the second discharge port of the nozzle body. By the instantaneous ejection of the air stored in the air storage unit, an air current with a high wind speed can be generated even with a small amount of air. Therefore, the granular material adhering to the first wall surface and the second wall surface can be satisfactorily blown off by the air ejected from the first discharge port and the second discharge port, respectively. Moreover, since the air is ejected intermittently, the consumption of air can be reduced. Thus, energy saving can be achieved by suppressing air consumption.

[0020] The powder processing apparatus according to another aspect of the present invention includes a container for storing powder, and an air purge nozzle for cleaning the powder adhering to the inner surface of the container with air. The air purge nozzle is the aforementioned air purge nozzle.

[0021] According to this configuration, the effects of the aforementioned air purge nozzle can be achieved.

[0022] The container has an opening, and the powder processing apparatus further includes a lid for closing at least a part of the opening. The air purge nozzle may be attached to the lid.

[0023] A plurality of air purge nozzles may be provided.

[0024] The container is a mixing drum for mixing a plurality of types of powder. The inner surface of the mixing drum has a bottom surface and a side surface rising from the periphery of the bottom surface. A rotating body rotating about a rotation axis perpendicular to the bottom surface may be provided in the mixing drum.

[0025] In that case, the side surface includes a peripheral wall surface extending in the circumferential direction of rotation of the rotating body and having a part of the circumferential direction cut out, a flat wall surface extending from one end of the peripheral wall surface to the side opposite to the rotating body side, and a rear surface extending substantially parallel to the second pipe portion from the flat wall surface. The first wall surface may be the flat wall surface, and the second wall surface may be the rear surface.

[0026] With this configuration, the powder adhering to the flat wall surface and the rear surface of the mixing drum can be cleaned well.

[0027] Also, the container is a loader hopper for transporting powder to a supply destination. The inner surface of the loader hopper includes a substantially cylindrical cylindrical wall surface and a substantially conical conical wall surface narrowing downward from the lower end of the cylindrical wall surface. The first wall surface may be the cylindrical wall surface, and the second wall surface may be the conical wall surface.

[0028] With this configuration, the powder adhering to the cylindrical wall surface and the conical wall surface of the loader hopper can be cleaned well.

[0029] Another aspect of the air purge method according to the present invention is an air purge method for discharging air from a nozzle body toward an object to clean the granular material adhering to the object, including: an air storage step of closing a valve interposed in an air flow pipe through which the air supplied to the nozzle body flows, and storing the air in an air storage portion interposed upstream of the valve in the air flow direction in the air flow pipe; and an air discharge step of opening the valve and discharging the air from the nozzle body after the air storage step, wherein the air storage step and the air discharge step are alternately repeated.

[0030] According to this method, when the valve is closed, air accumulates in the air storage portion, increasing the internal pressure of the air storage portion. Then, when the valve is opened, the internal pressure of the air storage portion is instantaneously released, and the air is ejected from the nozzle body like an air cannon. Therefore, the granular material adhering to the object can be effectively blown off by the air ejected from the nozzle body. Thus, the granular material can be effectively cleaned from the object. Moreover, since the air is ejected intermittently, the air consumption can be reduced. Therefore, energy saving can be achieved by suppressing air consumption.

Effects of the Invention

[0031] According to the present invention, the granular material can be effectively cleaned from the object.

Brief Description of the Drawings

[0032]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0033] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0034] <Weighing and Mixing Device> FIG. 1 is a diagram schematically showing the configuration of a weighing and mixing device 1 and a transport device 2 according to an embodiment of the present invention.

[0035] The weighing and mixing device 1 is a device that weighs and mixes various powder particles such as plastic pellets, crushed materials, and additives that are raw materials for plastic products. The weighing and mixing device 1 includes a raw material supply unit 11, a weighing unit 12, and a mixing unit 13.

[0036] The raw material supply unit 11 is provided with a plurality (four in the configuration shown in FIG. 1) of raw material hoppers 21. Different types of powder particles are supplied to each raw material hopper 21 by air transportation and stored. Further, each raw material hopper 21 is provided with a screw feeder 22. The powder particles stored in the raw material hopper 21 are discharged from the raw material hopper 21 by the operation of the screw feeder 22.

[0037] The metering unit 12 is provided with a metering hopper 23. The granular material discharged from each raw material hopper 21 is received by the metering hopper 23. The lower part of the metering hopper 23 is formed in a tapered shape, and a discharge port 24 is formed at its lower end. The metering hopper 23 is provided with a gate shutter 25 for opening and closing the discharge port 24. Further, the metering hopper 23 is provided with a load cell 26 for measuring the mass of the granular material stored in the metering hopper 23.

[0038] When the operation of the screw feeder 22 of the raw material hopper 21 for storing the granular material to be metered is started with the gate shutter 25 closed, the granular material discharged from the raw material hopper 21 is stored in the metering hopper 23. While the granular material stored in the metering hopper 23 is being metered by the load cell 26, the operation of the screw feeder 22 of the raw material hopper 21 is continued. When the quantitative amount is metered by the load cell 26, the operation of the screw feeder 22 is stopped. By sequentially controlling the operation of the screw feeder 22 of each raw material hopper 21, a plurality of types of granular materials mixed at a predetermined ratio (proportion) are stored in the metering hopper 23. When the gate shutter 25 is opened in this state, the plurality of types of granular materials stored in the metering hopper 23 are discharged from the discharge port 24.

[0039] The mixing unit 13 is arranged below the metering unit 12. The mixing unit 13 includes a mixing drum 31. An agitator 32 is rotatably provided in the mixing drum 31. The agitator 32 is rotated by the power of a motor 33. In the present embodiment, the rotation direction of the agitator 32 is counterclockwise when viewed from the front side (front). A discharge port 34 is formed at the lower end of the mixing drum 31. The mixing drum 31 is provided with a shutter valve 35 for opening and closing the discharge port 34.

[0040] With the shutter valve 35 closed, the granular material discharged from the discharge port 24 of the metering hopper 23 of the metering unit 12 is received by the mixing drum 31, and the granular material is stored in the mixing drum 31. When the motor 33 is driven and the agitator 32 is rotated, a plurality of types of granular materials in the mixing drum 31 are mixed together. When a certain period of time has elapsed and the granular materials in the mixing drum 31 are sufficiently mixed, the shutter valve 35 is opened. When the shutter valve 35 is opened, the mixed material composed of the plurality of types of mixed granular materials is discharged from the discharge port 34 of the mixing drum 31.

[0041] <Transport device> The transport device 2 is a device that transports the mixed material from the metering and mixing device 1 and feeds the transported mixed material into the molding machine. The transport device 2 includes a supply hopper 41 disposed below the mixing drum 31 and a loader hopper 42 disposed above the molding machine. The mixed material discharged from the discharge port 34 of the mixing drum 31 is received by the supply hopper 41. The lower part of the supply hopper 41 is formed in a tapered shape, and one end of a transport pipe 43 is connected to the lower end thereof via a gate 44. The other end of the transport pipe 43 is connected to the loader hopper 42.

[0042] When the air in the loader hopper 42 is sucked out with the gate 44 open, the mixed material stored in the supply hopper 41 is pneumatically transported through the transport pipe 43 to the loader hopper 42. The mixed material transported to the loader hopper 42 is fed into the molding machine through a discharge pipe 45 connected to the bottom of the loader hopper 42.

[0043] <Air purge nozzle> An air purge nozzle 51 is provided in the mixing section 13 of the metering and mixing device 1. The air purge nozzle 51 includes a nozzle body 52 provided across the inside and outside of the mixing drum 31, and an air supply line 53 connected to the nozzle body 52 for supplying air to the nozzle body 52. The air supply line 53 includes an air flow pipe 54 through which compressed air from an air supply source flows. A valve 55 that is opened and closed to control the flow of compressed air in the air flow pipe 54 is interposed in the air flow pipe 54. Further, a buffer tube 56 having an inner diameter larger than the inner diameter of the air flow pipe 54 is interposed in the air flow pipe 54 at a position upstream of the valve 55 in the flow direction of the compressed air in the air flow pipe 54, that is, at a position between the air supply source and the valve 55.

[0044] When the valve 55 is closed, the compressed air from the air supply source accumulates in the buffer tube 56, and the internal pressure of the buffer tube 56 increases to the supply pressure. Then, when the valve 55 is opened, the internal pressure of the buffer tube 56 is instantaneously released, and air is ejected from the nozzle body 52 into the mixing drum 31 like an air cannon.

[0045] In addition, two air purge nozzles 61 are provided in the loader hopper 42 of the transport device 2. Each air purge nozzle 61 includes a nozzle body 62 provided across the inside and outside of the loader hopper 42, and an air supply line 63 connected to the nozzle body 62 for supplying air to the nozzle body 62. The air supply line 63 includes an air flow pipe 64 through which compressed air from an air supply source flows. A valve 65 that is opened and closed to permit and block the flow of compressed air in the air flow pipe 64 is installed in the air flow pipe 64. Further, a buffer tube 66 having an inner diameter larger than the inner diameter of the air flow pipe 64 is interposed in the air flow pipe 64 at a position upstream of the valve 65 in the flow direction of the compressed air in the air flow pipe 64, that is, at a position between the air supply source and the valve 65.

[0046] When the valve 65 is closed, compressed air from the air supply source accumulates in the buffer tube 66, and the internal pressure of the buffer tube 66 increases to the supply pressure. Then, when the valve 65 is opened, the internal pressure of the buffer tube 66 is instantaneously released, and air is ejected from the nozzle body 62 into the loader hopper 42 like an air cannon.

[0047] <Nozzle body (mixing drum)> Figure 2 is a side view of the metering section 12 and a cross-sectional view of the mixing section 13 of the metering and mixing device 1. Figure 3 is a front view of the metering section 12 and a perspective view of the mixing section 13, showing a part of the configuration of the mixing section 13 with some omissions.

[0048] The inner surface of the mixing drum 31 has a bottom surface 71 and a side surface 72 rising from the periphery of the bottom surface 71.

[0049] The bottom surface 71 is inclined at a constant inclination angle (for example, about 45°) downward to the front. A rotating shaft 73 is rotatably provided on the bottom surface 71 around a rotation axis perpendicular to the bottom surface 71. The agitator 32 is coupled to the rotating shaft 73 and is supported on the rotating shaft 73 in a non-rotatable relative manner. A motor 33 is disposed on the rear side (lower side) of the bottom surface 71, and the rotating shaft of the motor 33 is non-rotatably connected to the rotating shaft 73.

[0050] The side surface 72 includes a peripheral wall surface 74 that extends in the circumferential direction of rotation of the agitator 32 and has a part (a rear part) in the circumferential direction of rotation cut out, a substantially triangular flat wall surface 75 that extends from both left and right ends of the peripheral wall surface 74 to the side opposite to the agitator 32 side, that is, the rear side, and a rear surface 76 that connects the left and right flat wall surfaces 75. The left and right flat wall surfaces 75 face each other in the left - right direction and are parallel to each other. At the upper end of the peripheral wall surface 74, an annular plate - shaped drum annular portion 77 along the peripheral wall surface 74 is formed. The openings surrounded by the left and right flat wall surfaces 75, the upper ends of the rear surface 76, and the drum annular portion 77 are an inlet 78 for receiving the granular material discharged from the discharge port 24 of the metering hopper 23 into the mixing drum 31. Further, above each flat wall surface 75, a guide plate 79 for guiding the granular material discharged from the discharge port 24 of the metering hopper 23 to the inlet 78 is provided. The left and right guide plates 79 are inclined so as to approach each other downward.

[0051] FIG. 4 is a view of the mixing drum 31 of the mixing section 13 as seen from the upper side (front side) in the axial direction of rotation of the agitator 32.

[0052] The opening 81 surrounded by the drum annular portion 77 is covered with a lid portion 82 as shown in FIG. 1, except for a part on the rear side. As shown in FIG. 4, a nozzle base 83 for holding the nozzle body 52 of the air purge nozzle 51 is disposed at a part on the rear side of the opening 81, that is, a portion not covered by the lid portion 82. The nozzle base 83 is in the shape of a plate extending in the left - right direction, straddles the drum annular portion 77, and both left and right end portions are fixed to the drum annular portion 77 by fixing tools 84. Further, a circular nozzle insertion hole 85 is formed through the nozzle base 83 at a position as close as possible to the right end at the portion facing the opening 81.

[0053] FIG. 5 is a side view of the nozzle body 52 of the air purge nozzle 51.

[0054] The nozzle body 52 integrally has a circular tubular insertion pipe portion 91 inserted into the nozzle insertion hole 85 of the nozzle base 83, a circular tubular first pipe portion 92 continuous with the insertion pipe portion 91, and a circular tubular second pipe portion 93 continuous with the first pipe portion 92.

[0055] The insertion pipe portion 91 is provided so as to straddle inside and outside the mixing drum 31. Outside the mixing drum 31, an air flow pipe 54 (see FIG. 1) of the air supply line 53 is connected to the end portion of the insertion pipe portion 91.

[0056] FIG. 6 is a cross-sectional view obtained by cutting the first pipe portion 92 in a cross-section perpendicular to its center line.

[0057] As shown in FIGS. 2 and 5, inside the mixing drum 31, the first pipe portion 92 bends or curves horizontally from the insertion pipe portion 91 and extends rearward in parallel with the right flat wall surface 75 at a position 20 mm apart from the right flat wall surface 75 of the mixing drum 31.

[0058] A plurality of first discharge ports 94 are formed in a row at equal intervals in a portion of the first pipe portion 92 that extends in parallel with the flat wall surface 75. As shown in FIG. 6, each first discharge port 94 opens in a direction that is diagonally downward to the right and inclined at a first angle θ1 with respect to the right flat wall surface 75. Therefore, when air is supplied to the nozzle body 52, air is discharged from each first discharge port 94 in a direction inclined at the first angle θ1 with respect to the right flat wall surface 75. The first angle θ1 is set to an angle within the range of 30° or more and 80° or less, for example, 45°.

[0059] As shown in FIGS. 3 and 5, the second pipe portion 93 bends or curves at a right angle to the left from the first pipe portion 92 and extends leftward in parallel with both the bottom surface 71 and the rear surface 76 of the mixing drum 31 at a position approximately 10 mm apart from the rear surface 76 toward the front side. As shown in FIG. 5, a second discharge port 95 is formed in the second pipe portion 93. The second discharge port 95 opens in a direction that is diagonally downward to the front and inclined at a second angle θ2 with respect to the rear surface 76. Therefore, when air is supplied to the nozzle body 52, air is discharged from the second discharge port 95 in a direction inclined at the second angle θ2 with respect to the rear surface 76. The second angle θ2 is set to an angle within the range of 30° or more and 80° or less, for example, 30°.

[0060] Further, a third discharge port 96 is formed at the position of the boundary between the insertion pipe portion 91 of the first pipe portion 92, that is, the position where bending or curving starts. The third discharge port 96 opens in a direction parallel to the inner surface of the lid portion 82 on the lid portion 82 side. Therefore, when air is supplied to the nozzle body 52, air is discharged from the third discharge port 96 in a direction parallel to the inner surface of the lid portion 82.

[0061] <Nozzle body (Loader hopper)> FIG. 7 is a cross-sectional view of the loader hopper 42.

[0062] The loader hopper 42 includes a substantially cylindrical upper portion 101, a substantially conical lower portion 102 that tapers downward, and a substantially disk-shaped lid 104 that closes the opening 103 at the upper end of the upper portion 101 from above. By the loader hopper 42 including the upper portion 101 and the lower portion 102, the inner surface of the loader hopper 42 has a substantially cylindrical cylindrical wall surface 105 and a substantially conical conical wall surface 106 that narrows downward from the lower end of the cylindrical wall surface 105.

[0063] FIG. 8 is a cross-sectional view of the lid 104 of the loader hopper 42.

[0064] The nozzle bodies 62 of the two air purge nozzles 61 are held by the lid 104. A cylindrical nozzle insertion portion 107 is formed to protrude upward at a position that is rotationally symmetric about the center of the lid 104. The nozzle body 62 integrally has a circular tubular insertion pipe portion 111 inserted into the nozzle insertion portion 107, a circular tubular first pipe portion 112 continuous with the insertion pipe portion 111, and a circular tubular second pipe portion 113 continuous with the first pipe portion 112.

[0065] Outside the loader hopper 42, an air flow pipe 64 (see FIG. 1) of the air supply line 63 is connected to the end of the insertion pipe portion 111.

[0066] As shown in FIGS. 7 and 8, the first pipe portion 112 extends downward in a straight line with the insertion pipe portion 111 inside the loader hopper 42 and is parallel to the cylindrical wall surface 105 of the loader hopper 42. A plurality of first discharge ports 114 are formed in a row and arranged at equal intervals in the first pipe portion 112. Each first discharge port 114 opens in a direction orthogonal to the cylindrical wall surface 105. Therefore, when air is supplied to the nozzle body 62, air is discharged from each first discharge port 114 in a direction orthogonal to the cylindrical wall surface 105.

[0067] As shown in FIG. 7, the second pipe portion 113 extends from the first pipe portion 112 by bending or curving so as to be parallel to the conical wall surface 106 of the loader hopper 42. A plurality of second discharge ports 115 are formed in a row and arranged at equal intervals in the second pipe portion 113. Each second discharge port 115 opens in a direction orthogonal to the conical wall surface 106. Therefore, when air is supplied to the nozzle body 62, air is discharged from each second discharge port 115 in a direction orthogonal to the conical wall surface 106.

[0068] The second pipe portion 113 of the nozzle body 62 through which the insertion pipe portion 111 is inserted into one nozzle insertion portion 107 and the second pipe portion 113 of the nozzle body 62 through which the insertion pipe portion 111 is inserted into the other nozzle insertion portion 107 are bent or curved on opposite sides. As a result, the two nozzle bodies 62 are rotationally symmetric about the center of the lid 104.

[0069] <Cleaning process> As shown in FIG. 1, a control unit 121 is provided in a system including the metering and mixing device 1 and the transport device 2. The control unit 121 is configured to include a microcomputer (microcontroller unit), and the microcomputer incorporates a non-volatile memory such as a CPU, a flash memory, and a volatile memory such as a DRAM (Dynamic Random Access Memory).

[0070] In accordance with the discharging process in which the mixed material is discharged from the discharge port 34 of the mixing drum 31 of the metering and mixing device 1, the control unit 121 controls the opening and closing of the valve 55 to perform a cleaning process for cleaning the granular material adhering to the inner surface of the mixing drum 31. Also, in the discharging process in which the mixed material is discharged from the loader hopper 42 of the transport device 2, the control unit 121 controls the opening and closing of the valve 65 to perform a cleaning process for cleaning the granular material adhering to the inner surface of the loader hopper 42.

[0071] FIG. 9 is a flowchart showing the flow of the cleaning process.

[0072] First, the cleaning process for cleaning the granular material adhering to the inner surface of the mixing drum 31 will be described.

[0073] In the mixing process of mixing the mixed material, the agitator 32 is rotated counterclockwise as viewed from the front side. Therefore, immediately after the end of the mixing process, a large amount of the mixed material accumulates in the right rear side portion rather than the left rear side portion in the mixing drum 31. When the shutter valve 35 of the mixing drum 31 is opened and the discharge port 34 is opened, the mixed material in the mixing drum 31 flows on the bottom surface 71 toward the discharge port 34 due to the inclination of the bottom surface 71 of the mixing drum 31 and is discharged to the outside from the discharge port 34. In the mixing drum 31, there is a distribution in the flow rate of the mixed material. In the zone where the agitator 32 moves upward, the flow is relatively slow, and in the zone where the agitator 32 moves downward, the flow is relatively fast. In the structure of the present embodiment, since the flow of the mixed material is gentle in the right rear side portion in the mixing drum 31, electrostatically charged granular material tends to remain at the corner formed by the rear surface 76 of the mixing drum 31 and the right flat wall surface 75, that is, the right rear side portion.

[0074] Therefore, when a predetermined start time has elapsed since the start of the discharge process due to the opening of the discharge port 34, the cleaning process is started, and when it is before a predetermined end time since the end of the discharge process due to the closing of the discharge port 34 by the shutter valve 35, the cleaning process is ended. The start time may be set within a range of 0 seconds or more and 30 seconds or less. The end time may be set within a range of 0 seconds or more and 60 seconds or less.

[0075] In the cleaning process, the supply of compressed air from the air supply source to the air flow pipe 54 of the air supply line 53 of the air purge nozzle 51 is started. Also, the valve 55 of the air supply line 53 is closed (step S1). In the state where the valve 55 is closed, the compressed air from the air supply source is stored in the buffer tube 56 of the air supply line 53. As a result, the internal pressure of the buffer tube 56 increases.

[0076] When a predetermined first time has elapsed since the valve 55 was closed (YES in step S2), the valve 55 is opened (step S3). When the valve 55 is opened, the internal pressure of the buffer tube 56 is instantaneously released, and air is ejected from the first discharge port 94, the second discharge port 95, and the third discharge port 96 of the nozzle body 52 of the air purge nozzle 51. The first time may be set within a range of 0.05 seconds or more and 1 second or less.

[0077] The air ejected from the first discharge port 94 collides with the powder particles adhering to the flat wall surface 75 on the right side of the mixing drum 31, and then flows downward along the flat wall surface 75. Also, the air ejected from the second discharge port 95 collides with the powder particles adhering to the bottom surface 71 of the mixing drum 31, and then flows downward along the bottom surface 71. Therefore, the powder particles blown off by the air from the bottom surface 71 and the flat wall surface 75 on the right side flow downward on the air. As a result, the powder particles are cleaned from the rear surface 76, the flat wall surface 75 on the right side, and the corner formed by the rear surface 76 and the flat wall surface 75 on the right side. Further, the air ejected from the third discharge port 96 collides with the powder particles adhering to the inner surface of the lid portion 82 and blows off the powder particles.

[0078] When a predetermined second time has elapsed since the valve 55 was opened (YES in step S4), it is determined whether to end the cleaning process (step S5). The second time may be set within a range of 0.05 seconds or more and 1 second or less.

[0079] If it is not the timing to end the cleaning process (NO in step S5), the valve 55 is closed again (step S1). Then, when the first time has elapsed since the valve 55 was closed (YES in step S2), the valve 55 is opened (step S3). When the second time has elapsed since the valve 55 was opened (YES in step S4), it is determined whether to end the cleaning process (step S5). In this way, until the cleaning process ends, the processes of steps S1 to S5 are repeated, and air is intermittently discharged from the first discharge port 94, the second discharge port 95, and the third discharge port 96 of the nozzle body 52 of the air purge nozzle 51.

[0080] When the timing to end the cleaning process arrives (YES in step S5), the cleaning process is ended.

[0081] Next, a cleaning process for cleaning the powder particles adhering to the inner surface of the loader hopper 42 will be described.

[0082] When the transportation of the mixed material to the loader hopper 42 is started, the mixed material transported into the loader hopper 42 is discharged through the discharge pipe 45 connected to the bottom of the loader hopper 42. After the discharge, electrostatically charged powder particles tend to adhere to and remain on the cylindrical wall surface 105 and the conical wall surface 106 of the loader hopper 42. Since the conical wall surface 106 is inclined with respect to the vertical direction, powder particles tend to remain particularly on the conical wall surface 106.

[0083] Therefore, after the pneumatic transportation of the mixed material to the loader hopper 42 ends, the cleaning process is started. As shown in FIG. 7, the lid 104 of the loader hopper 42 is provided with a check valve 122 for venting the positive pressure in the loader hopper 42 by air purge. Since the pressure in the loader hopper 42 temporarily rises due to air purge, if excess air escapes through the pipeline, there may be a reverse flow in the direction opposite to the correct air flow direction. However, by venting air from the check valve 122, excess air can be vented.

[0084] In the cleaning process, the supply of compressed air from the air supply source to the air flow pipe 64 of each air supply line 63 of the two air purge nozzles 61 is started. Also, the valve 65 of each air supply line 63 is closed (step S1). When the valve 65 is closed, the compressed air from the air supply source is stored in the buffer tube 66 of the air supply line 63. As a result, the internal pressure of the buffer tube 66 increases.

[0085] When a predetermined first hour elapses after the valve 65 is closed (YES in step S2), the valve 65 of one of the air purge nozzles 61 is opened (step S3). At this time, the other valve 65 remains closed. When the valve 65 is opened, the internal pressure of the buffer tube 66 on the upstream side of the valve 65 is instantaneously released, and air is ejected like an air cannon from the first discharge port 114 and the second discharge port 115 of the nozzle body 62 of one of the air purge nozzles 61.

[0086] The air discharged from the first discharge port 114 collides with the granular material adhering to the cylindrical wall surface 105 of the loader hopper 42 and then flows toward the discharge pipe 45. Also, the air discharged from the second discharge port 115 collides with the granular material adhering to the conical wall surface 106 of the loader hopper 42 and then flows toward the discharge pipe 45. Therefore, the granular material blown off from the cylindrical wall surface 105 and the conical wall surface 106 by air flows along with the air toward the discharge pipe 45 and is discharged through the discharge pipe 45. As a result, the granular material is cleaned from the cylindrical wall surface 105, the conical wall surface 106, and the corner formed by the cylindrical wall surface 105 and the conical wall surface 106.

[0087] When a predetermined second time has elapsed since the valve 65 was opened (YES in step S4), it is determined whether to end the cleaning process (step S5).

[0088] When it is not the timing to end the cleaning process (NO in step S5), the valve 65 of one air purge nozzle 61 is closed (step S1). Then, when the first hour has elapsed since the valve 65 was closed (YES in step S2), the valve 65 of the other air purge nozzle 61 is opened (step S3). When a predetermined second time has elapsed since the valve 65 was opened (YES in step S4), it is determined whether to end the cleaning process (step S5). When it is not the timing to end the cleaning process (NO in step S5), the valve 65 of the other air purge nozzle 61 is closed (step S1). When the first hour has elapsed since the valve 65 was closed (YES in step S2), the valve 65 of one air purge nozzle 61 is opened (step S3). In this way, until the cleaning process ends, the processes of steps S1 to S5 are repeated, and air is intermittently discharged alternately from the first discharge port 114 and the second discharge port 115 of the nozzle body 62 of one air purge nozzle 61 and from the first discharge port 114 and the second discharge port 115 of the nozzle body 62 of the other air purge nozzle 61.

[0089] <Effect> As described above, by intermittently discharging air from the first discharge port 94 and the second discharge port 95 of the nozzle body 52 of the air purge nozzle 51, the granular material can be effectively cleaned from the rear surface 76 and the right flat wall surface 75 of the mixing drum 31 and from the corner formed by the rear surface 76 and the right flat wall surface 75. Also, by intermittently discharging air from the first discharge port 114 and the second discharge port 115 of the nozzle body 62 of the air purge nozzle 61, the granular material can be effectively cleaned from the cylindrical wall surface 105 and the conical wall surface 106 of the loader hopper 42 and from the corner formed by the cylindrical wall surface 105 and the conical wall surface 106. Therefore, the granular material adhering to the inner surface of the mixing drum 31 can be cleaned well regardless of the difference in the charged state.

[0090] In addition, since air is intermittently ejected from the air purge nozzles 51 and 61, the air consumption can be reduced. Therefore, energy saving can be achieved by suppressing air consumption. By alternately using the air purge nozzles 51 and 61, the wind speed of the air ejected with respect to the injection amount per time can be maintained high, and further, since the injection position changes, the air can be evenly delivered into the loader hopper.

[0091] <Modification Example> As described above, the embodiments of the present invention have been described, but the present invention can also be implemented in other forms.

[0092] For example, in the above-described embodiment, the configuration in which the first discharge ports 94 and 114 are aligned in a row at equal intervals is taken up, but they do not necessarily have to be at equal intervals. When there are locations where air needs to be intensively blown within the portion where air is to be blown, the first discharge ports 94 and 114 that discharge air toward the said locations may be densely provided, and the first discharge ports 94 and 114 that discharge air toward portions other than the said locations may be sparsely provided. In the configuration where the first discharge ports 94 and 114 are aligned in a row at equal intervals, air can be uniformly blown onto the portion where air is to be blown, and the granular material can be uniformly cleaned from the said portion. The same applies to the second discharge port 115.

[0093] In the cleaning process of the loader hopper 42, it is assumed that air is alternately discharged from one air purge nozzle 61 and the other air purge nozzle 61, but air may be discharged from those air purge nozzles 61 simultaneously. Also, although it is assumed that the cleaning process is performed after the mixed material is transported to the loader hopper 42, the cleaning process may be performed during transportation as long as it does not affect the transportation air.

[0094] Three or more air purge nozzles 61 may be provided in the loader hopper 42.

[0095] The inner surface of the metering hopper 23 is the object, and the air purge nozzle according to the present invention may be provided as an air purge nozzle for cleaning the powder and granular material adhering to the inner surface of the metering hopper 23 with air.

[0096] Also, although the metering and mixing device 1 and the transport device 2 have been taken up, the present invention can also be applied to other types of powder and granular material processing devices, such as a drying device for drying powder and granular materials.

[0097] In addition, various design changes can be made to the above-described configuration within the scope of the matters described in the claims.

Explanation of reference numerals

[0098] 1: Metering and mixing device (powder and granular material processing device) 2: Transport device (powder and granular material processing device) 31: Mixing drum (container) 32: Agitator (rotating body) 42: Loader hopper (container) 51, 61: Air purge nozzle 52, 62: Nozzle body 53, 63: Air supply line 54, 64: Air flow pipe 55, 65: Valve 56, 66: Buffer tube (air reservoir) 76: Rear surface (second wall surface) 75: Flat wall surface (first wall surface) 92, 112: First pipe section 93, 113: Second pipe section 94, 114: First discharge port 95, 115: Second discharge port 103: Opening 104: Lid 105: Cylindrical wall surface (first wall surface) 106: Conical wall surface (second wall surface) θ1: First angle θ2: Second angle

Claims

1. An air purge nozzle fixedly provided for an object having a first wall surface and a second wall surface provided on the downstream side of the first wall surface in the discharge direction of the powder particles and intersecting the first wall surface, for cleaning the powder particles adhering to the object with air, including a nozzle body, and an air supply line connected to the nozzle body for supplying air to the nozzle body. The nozzle body is formed in a tubular shape having a first pipe portion extending substantially parallel to the first wall surface and a second pipe portion extending substantially parallel to the second wall surface, a first discharge port for discharging air toward the first wall surface is formed in the first pipe portion, a second discharge port for discharging air toward the second wall surface is formed in the second pipe portion, and the first pipe portion and the second pipe portion are provided in this order from the upstream side in the flow direction of the air flowing through the nozzle body from the air supply line. The air purge nozzle.

2. The first discharge port is provided so as to discharge air in a direction inclined at a first angle with respect to the first wall surface so that the air has a downward velocity component along the first wall surface, The second discharge port is provided so as to discharge air in a direction inclined at a second angle with respect to the second wall surface so that the air has a downward velocity component along the second wall surface. The air purge nozzle according to claim 1.

3. The first angle and the second angle are each set within a range of 30° or more and 80° or less. The air purge nozzle according to claim 2.

4. The first discharge port is provided so as to discharge air in a direction perpendicular to the first wall surface, The second discharge port is provided so as to discharge air in a direction perpendicular to the second wall surface. The air purge nozzle according to claim 1.

5. The air supply line is an air flow pipe through which air from an air supply source flows, A valve that controls the flow of air in the air flow pipe, An air storage part that is installed upstream of the valve in the air flow direction in the air flow pipe and stores air in a state where the flow of air is blocked by the valve, and the air purge nozzle according to any one of claims 1 to 4.

6. A container having a first wall surface and a second wall surface provided on the downstream side of the first wall surface in the discharge direction of the powder and granular material and intersecting the first wall surface, and containing the powder and granular material, An air purge nozzle that is fixedly provided with respect to the container and cleans the powder and granular material adhering to the inner surface of the container with air, The air purge nozzle is the air purge nozzle according to any one of claims 1 to 5, and is a powder and granular material processing apparatus.

7. The container has an opening, Further includes a lid that closes at least a part of the opening, The air purge nozzle is attached to the lid, and the powder and granular material processing apparatus according to claim 6.

8. A plurality of the air purge nozzles are provided, and the powder and granular material processing apparatus according to claim 6 or 7.

9. The container is a mixing drum for mixing a plurality of types of powder and granular materials, The inner surface of the mixing drum has a bottom surface and a side surface rising from the periphery of the bottom surface, In the mixing drum, a rotating body that rotates around a rotation axis perpendicular to the bottom surface is provided, and the powder and granular material processing apparatus according to any one of claims 6 to 8.

10. The side surface includes a peripheral wall surface that extends in the circumferential direction of rotation of the rotating body and a part of the circumferential direction is cut out, a flat wall surface that extends from one end of the peripheral wall surface to the side opposite to the rotating body side, and a rear surface that extends from the flat wall surface substantially parallel to the second pipe portion, The first wall surface is the flat wall surface, The granular material processing apparatus according to claim 9, wherein the second wall surface is the rear surface.

11. The container is a loader hopper for transporting the granular material to a supply destination, The inner surface of the loader hopper includes a substantially cylindrical wall surface and a substantially conical wall surface that narrows downward from the lower end of the cylindrical wall surface, The first wall surface is the cylindrical wall surface, The granular material processing apparatus according to any one of claims 6 to 8, wherein the second wall surface is the conical wall surface.

12. An air purge method for discharging air from the nozzle body provided fixedly with respect to an object having a first wall surface and a second wall surface provided on the downstream side in the discharge direction of the granular material with respect to the first wall surface and intersecting the first wall surface, and having a first pipe portion extending substantially parallel to the first wall surface and a second pipe portion extending substantially parallel to the second wall surface, and formed in a tubular shape, a first discharge port for discharging air toward the first wall surface is formed in the first pipe portion, a second discharge port for discharging air toward the second wall surface is formed in the second pipe portion, and the first pipe portion and the second pipe portion are provided in this order from the upstream side in the flow direction of the air flowing through the nozzle body, and discharging air from the nozzle body toward the object to clean the granular material adhering to the object, An air storage step of closing a valve interposed in an air flow pipe through which air supplied to the nozzle body flows, and storing air in an air storage portion interposed on the upstream side in the air flow direction of the valve in the air flow pipe, After the air storage step, an air discharge step of opening the valve and discharging air from the nozzle body, An air purge method in which the air storage step and the air discharge step are alternately repeated.

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