JP2016085090A - Weighing device, and powder and granular material transporting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology capable of suppressing a measurement error for a weighing device of powder and granular materials, used with an air force transporting device.SOLUTION: This weighing device 4 comprises: a storage tank 41; measurement means for measuring powder and granular materials in the storage tank 41; and a suction nozzle 43. One end of the suction nozzle 43 is a suction port 431 placed inside of the storage tank 41, and the other end is connected to a transportation pipe 5 for suction transportation. The storage tank 41 comprises: a main storage part 71 in which powder and granular materials are temporarily stored; a sub storage part 72 in which powder and granular materials are secondarily stored; and a connection port 74 which connects between the main storage part 71 and the sub storage part 72. Powder and granular materials are supplied from the main storage part 71 through the connection port 74 to the sub storage part 72 by gravity. A part of the suction nozzle 43 including the suction port 431 is placed inside of the sub storage part 72 while it does not come into contact with the storage tank 41. As a result, a contact area between the suction nozzle 43, and powder and granular materials is minimized at the time of measurement of powder and granular materials, and a measurement error is suppressed.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a powder particle measuring device and a powder particle transport device.

  Conventionally, a measuring device for measuring a predetermined amount of powder particles such as resin pellets is known. A conventional weighing device is disclosed in Patent Document 1, for example. In the weighing hopper described in Patent Document 1, the granular material is transported from the weighing hopper to a transportation destination such as an injection molding machine by pneumatic transportation. At this time, if the transport pipe and the granular material stored inside the measuring hopper come into contact, a measuring error occurs when measuring the granular material in the measuring hopper.

  Therefore, in the weighing hopper described in Patent Document 1, the suction nozzle is fixed to the weighing hopper, and the end of the suction nozzle and the end of the suction transport pipe are arranged to face each other with a predetermined gap. Thereby, it is suppressed that a transportation error and the granular material stored inside the measurement hopper contact, and a measurement error arises.

Japanese Patent No. 4132485

  However, in the measuring device described in Patent Document 1, when the distance between the end of the suction nozzle and the end of the suction transport pipe changes, the amount of gas flowing into the suction transport pipe changes. Therefore, in order to stabilize the transport amount of the granular material, it is necessary to strictly adjust the positional relationship between the suction nozzle and the suction transport pipe. For this reason, when the weighing hopper is moved due to maintenance or the like, it takes time and labor to adjust the position again.

  The present invention has been made in view of such circumstances, and provides a technique capable of suppressing a measurement error while reducing labor for adjusting the position of a member in a granular material measurement device used together with an aerodynamic transportation device. For the purpose.

  In order to solve the above-mentioned problem, the first invention of the present application is a measuring device for a granular material, which measures a mass of a storage tank storing the granular material and the granular material stored in the storage tank. And a nozzle connected at one end to a transport pipe for suction and transportation, the storage tank including the granular material. A primary storage part where the primary storage part is stored, a secondary storage part where the granular material is secondary stored, a communication port which communicates the main storage part and the secondary storage part, and the secondary storage part A nozzle insertion port that communicates with the outside, and the sub-storage part is supplied with the powder by gravity from the main storage part through the communication port, and the suction port of the nozzle Is included in the sub-storage part and at a position not in contact with the storage tank.

  2nd invention of this application is a measuring device of 1st invention, Comprising: The said storage tank further has the interruption | blocking part, The space inside the said storage tank is the said main storage part and the said sub-storage by the said interruption | blocking part. Divided into parts.

  3rd invention of this application is a measuring device of 1st invention or 2nd invention, Comprising: The said communicating port is arrange | positioned at the lower end part of the said main storage part.

  4th invention of this application is a measuring apparatus of 3rd invention, Comprising: As for the said main storage part, at least one part containing the said lower end part is dented as it goes below.

  5th invention of this application is a measuring device in any one of 1st invention thru | or 4th invention, Comprising: The said auxiliary storage part is filled with the said granular material supplied with the gravity from the said main storage part. And a nozzle arrangement part in which the nozzle is arranged and extends upward from the natural filling part, the nozzle insertion port is provided in the nozzle arrangement part, and the suction port of the nozzle is It arrange | positions in the boundary vicinity of the said natural filling part and the said nozzle arrangement | positioning part.

  According to a sixth aspect of the present invention, the measuring device according to any one of the first to fifth aspects, the transport pipe for suction transport, one end of which is connected to the nozzle, and the gas inside the transport pipe are sucked. A granular material transport device having a suction device and a granular material transport destination connected to the other end of the transport pipe.

  According to the first to sixth inventions of the present application, the nozzle is disposed in the sub-reservoir and does not contact the reservoir. Thereby, when a granular material is stored in a storage tank, the contact area of a granular material and a nozzle can be made small. Therefore, the measurement error at the time of measuring the granular material in a storage tank can be suppressed.

  In particular, according to the third and fourth inventions of the present application, the granular material stored inside the main storage part is efficiently directed to the sub-storage part. Thereby, it can suppress that a granular material remains in a storage tank.

  In particular, according to the fifth aspect of the present invention, the nozzle and the granular material are not in contact with each other, or the contact area between the nozzle and the granular material can be further reduced. Thereby, the measurement error at the time of measuring the granular material in a storage tank can be suppressed more. Moreover, the airflow that flows in from the nozzle insertion port and travels toward the suction port of the nozzle easily acts on the granular material, and the granular material does not easily disturb the airflow. Therefore, a granular material can be efficiently conveyed at the time of pneumatic transportation.

It is a schematic diagram of a granular material transportation system concerning a 1st embodiment. It is a flow chart which shows a granular material transportation process in a granular material transportation system concerning a 1st embodiment. 1 is a schematic cross-sectional view of a weighing device according to a first embodiment. It is a perspective view of the measurement hopper which concerns on 1st Embodiment. It is a fragmentary sectional view of the measurement hopper and suction nozzle concerning a 1st embodiment. It is a schematic sectional drawing of the measuring device which concerns on a comparative example. It is a schematic sectional drawing of the measuring device which concerns on a modification. It is a schematic sectional drawing of the measuring device which concerns on a modification. It is a perspective view of the measurement hopper which concerns on a modification.

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

<1. Granule Transport System According to One Embodiment>
<1-1. Configuration of powder transportation system>
FIG. 1 is a schematic view of a granular material transport system 1 according to an embodiment of the present invention. The granular material transport system 1 includes a material supply unit 2, an airflow generation unit 3, a weighing device 4, a transport pipe 5, a granular material transport destination 6, and a control unit 10. The granular material transport system 1 of this embodiment transports the granular material supplied from the material supply unit 2 pneumatically to the granular material transport destination 6 after being measured by the measuring device 4.

  The material supply unit 2 includes a first material supply unit 21 and a second material supply unit 22. The first material supply unit 21 includes a first material supply source 211, a first tank 212, a first supply pipe 213, and an air cylinder 214.

  The first material supply source 211 stores resin pellets as a main material. The main material supplied from the first material supply source 211 is temporarily stored in the first tank 212. The first supply pipe 213 is a pneumatic transport pipe that connects the lower end of the first material supply source 211 and the first tank 212. The air cylinder 214 opens and closes an opening / closing lid 215 provided at the bottom of the first tank 212. The operation of the air cylinder 214 is controlled by the control unit 10.

  The second material supply unit 22 includes a second material supply source 221, a second tank 222, a second supply pipe 223, and a screw feeder 224. The second material supply source 221 stores additives such as a master batch. The additive supplied from the second material supply source 221 is temporarily stored in the second tank 222. The second supply pipe 223 is a pneumatic transport pipe that connects the lower end of the second material supply source 221 and the second tank 222. The screw feeder 224 is a device that supplies the material stored in the second tank 222 to the weighing hopper 41 described later while adjusting the supply amount. The operation of the screw feeder 224 is controlled by the control unit 10.

  The air flow generation unit 3 includes a suction blower 31, an exhaust pipe 32, a switching unit 33, a fine powder removal unit 34, and a filter 35. The suction blower 31 is an airflow generator that sucks the gas inside the exhaust pipe 32. The exhaust pipe 32 is an airflow pipe that connects the first tank 212, the second tank 222, and the inside of the airflow stirring device 61 described later and the suction blower 31.

  The exhaust pipe 32 includes a main pipe 321, a first exhaust pipe 322, a second exhaust pipe 323, and a third exhaust pipe 324. The main pipe 321 connects the suction blower 31 and the switching unit 33. The first exhaust pipe 322 connects the inside of the first tank 212 and the switching unit 33. The second exhaust pipe 323 connects the inside of the second tank 222 and the switching unit 33. The third exhaust pipe 324 connects the inside of a stirring drum 613 described later of the airflow stirring device 61 and the switching unit 33.

  The switching unit 33 is a flow path switching device that switches the connection state between the main pipe 321 and the exhaust pipes 322 to 324. The switching unit 33 has an exhaust port connected to the main pipe 321 and three intake ports respectively connected to the exhaust pipes 322 to 324. The switching unit 33 blocks communication between the main pipe 321 and each of the exhaust pipes 322 to 324 according to a command from the control unit 10, or connects either the main pipe 321 and the exhaust pipes 322 to 324.

  A fine powder removing unit 34 and a filter 35 are inserted in the main pipe 321. Thereby, a part of solid components and volatile components, such as a fine powder contained in the gas which flowed into main piping 321 from each exhaust piping 322-324, is removed. Therefore, the adhesion of these components to the suction blower 31 is suppressed.

  When the suction blower 31 is driven and the switching unit 33 causes the main pipe 321 and the first exhaust pipe 322 to communicate, the gas in the first tank 212 passes through the first exhaust pipe 322, the switching unit 33, and the main pipe 321. The suction blower 31 is sucked. Then, an air flow is generated from the first material supply source 211 through the first supply pipe 213 and into the first tank 212. As a result, the main material stored in the first material supply source 211 is supplied to the first tank 212 via the first supply pipe 213. When the control unit 10 drives the air cylinder 214, the opening / closing lid 215 provided at the bottom of the first tank 212 is opened, and the main material stored in the first tank 212 is supplied to the weighing hopper 41. The

  When the suction blower 31 is driven and the switching unit 33 causes the main pipe 321 and the second exhaust pipe 323 to communicate with each other, the gas in the second tank 222 causes the second exhaust pipe 323, the switching unit 33, and the main pipe 321 to be connected. To the suction blower 31. Then, an air flow is generated from the second material supply source 221 through the second supply pipe 223 into the second tank 222. As a result, the additive stored in the second material supply source 221 is supplied to the second tank 222 via the second supply pipe 223. When the control unit 10 drives the screw feeder 224, the additive stored in the second tank 222 is supplied to the weighing hopper 41.

  In the present embodiment, the second material supply unit 22 supplies the additive, but the present invention is not limited to this. The 2nd material supply part 22 may supply the resin pellet of another kind for mixing with the resin pellet which the 1st material supply part 21 supplies. The material supply unit 2 may have a third material supply unit in addition to the first material supply unit 21 and the second material supply unit 22. The third material supply unit supplies, for example, a molding failure product, a pulverized material (recycled material) obtained by pulverizing sprues and runners.

  The weighing device 4 includes a weighing hopper 41, a weight scale 42, and a suction nozzle 43. The weighing hopper 41 is a storage tank that temporarily stores the powder (main material and additive) supplied from the first material supply unit 21 and the second material supply unit 22. The weigh scale 42 is a weighing unit that measures the mass of the weighing hopper 41 and the mass of the granular material stored in the weighing hopper 41. The weight scale 42 of this embodiment is configured by a load cell. One end of the suction nozzle 43 serves as a suction port 431 disposed inside the weighing hopper 41. The other end of the suction nozzle 43 is connected to the transport pipe 5. The detailed configuration of the weighing device 4 will be described later.

  The transport pipe 5 is a transport pipe for transporting the granular material from the measuring device 4 to the granular material transport destination 6. One end of the transport pipe 5 is connected to the suction nozzle 43. Further, the other end of the transport pipe 5 is connected to a space between an outer cylinder portion 611 and an inner cylinder portion 612 of an airflow stirring device 61 described later.

  The granular material transport destination 6 includes an airflow stirring device 61, a supply hopper 62, and a molding machine 63. The airflow stirring device 61 is a device that stirs the granular material transported from the weighing hopper 41 through the transport pipe 5. The supply hopper 62 is a temporary storage unit for supplying the granular material stirred by the airflow stirring device 61 to the molding machine 63. The molding machine 63 according to the present embodiment is an injection molding machine that performs injection molding using the granular material as a material.

  The airflow stirring device 61 includes an outer cylindrical portion 611, an inner cylindrical portion 612, and a stirring drum 613. The outer cylinder part 611 is a substantially cylindrical member that extends vertically. The inner cylinder part 612 is a substantially cylindrical member that extends vertically inside the outer cylinder part 611. The lower end portion of the outer cylinder portion 611 is disposed below the lower end portion of the inner cylinder portion 612. The stirring drum 613 is disposed above the outer cylinder portion 611 and the inner cylinder portion 612. A third exhaust pipe 324 is connected above the stirring drum 613.

  A transport pipe 5 is connected to the side surface of the outer cylinder portion 611. Thereby, the granular material transported from the transport pipe 5 to the airflow stirring device 61 is first supplied to the space between the outer cylindrical portion 611 and the inner cylindrical portion 612. The space inside the inner cylinder portion 612 and the space inside the stirring drum 613 communicate with each other at the upper end of the inner cylinder portion 612. On the other hand, at the upper end portion of the outer cylinder portion 611, the space between the outer cylinder portion 611 and the inner cylinder portion 612 and the space inside the stirring drum 613 are blocked by a blocking plate 614.

  With such a configuration, when the suction blower 31 is driven and the switching unit 33 causes the main pipe 321 and the third exhaust pipe 324 to communicate with each other, the gas in the stirring drum 613 is transferred to the third exhaust pipe 324, the switching unit 33, and the main unit. The suction blower 31 is sucked through the pipe 321. When the pressure inside the stirring drum 613 is reduced, the suction nozzle 43 passes through the transport pipe 5, the space between the outer cylinder portion 611 and the inner cylinder portion 612, and the space inside the inner cylinder portion 612. An air flow toward the stirring drum 613 is generated. Thereby, the granular material stored in the inside of the measurement hopper 41 is transported to the airflow stirring device 61 through the transport pipe 5 and is stirred and fluidized in the stirring drum 613. As described above, the air flow generating unit 3, the suction nozzle 43, and the transport pipe 5 constitute an aerodynamic transport device.

  By stirring in the stirring drum 613, the main material supplied from the first material supply unit 21 and the additive supplied from the second material supply unit 22 are uniformly mixed. When the suction of the gas from the stirring drum 613 is stopped, the granular material that has been stirred in the stirring drum 613 naturally falls downward via the inner cylindrical portion 612 and the outer cylindrical portion 611 and moves to the supply hopper 62. To do.

<1-2. Flow of particulate transport>
Next, a procedure for supplying the granular material from the material supply unit 2 to the molding machine 63 will be described with reference to FIG. FIG. 2 is a flowchart showing a powder particle transport process to the molding machine 63 in the powder particle transport system 1.

  First, the main material is supplied from the first material supply unit 21 to the weighing hopper 41 (step S101). Specifically, the control unit 10 drives the suction blower 31 and causes the switching unit 33 to communicate the main pipe 321 and the first exhaust pipe 322. As a result, the main material is supplied from the first material supply source 211 into the first tank 212. After a predetermined time has elapsed, the supply of the main material from the first material supply source 211 to the first tank 212 is stopped. Thereafter, the control unit 10 drives the air cylinder 214 to open the opening / closing lid 215 provided at the bottom of the first tank 212. As a result, the entire amount of the main material stored in the first tank 212 naturally falls into the weighing hopper 41.

  Next, the weight of the main material supplied to the weighing hopper 41 is measured (step S102). At this time, the weighing scale 42 measures the weight of the main material stored in the weighing hopper 41 main body and the weighing hopper 41. The control unit 10 calculates the weight of the main material supplied to the weighing hopper 41 from the difference between the weight and the weight of the weighing hopper 41 body weighed in advance. Thereafter, the control unit 10 calculates the weight (addition amount) of the additive to be added from the weight of the main material calculated in Step S102 (Step S103).

  On the other hand, the additive is supplied from the second material supply unit 22 into the second tank 222. Specifically, the control unit 10 drives the suction blower 31 and causes the switching unit 33 to communicate the main pipe 321 and the second exhaust pipe 323. As a result, the additive is supplied from the second material supply unit to the second tank 222. After a predetermined time has elapsed, the supply of the additive from the second material supply source 221 to the second tank 222 is stopped. Thereafter, the control unit 10 drives the screw feeder 224 according to the addition amount calculated in step S103, and supplies a desired weight of additive into the weighing hopper 41 (step S104).

  Subsequently, the main material and additive stored in the weighing hopper 41 are pneumatically transported to the airflow stirring device 61 of the granular material transport destination 6 (step S105). Specifically, the control unit 10 drives the suction blower 31 and causes the switching unit 33 to communicate the main pipe 321 and the third exhaust pipe 324. Thereby, the main material and the additive are transported from the inside of the weighing hopper 41 to the airflow stirring device 61 through the suction nozzle 43 and the transport pipe 5. The main material and the additive transported into the airflow stirring device 61 are stirred in the stirring drum 613 through the space between the outer cylindrical portion 611 and the inner cylindrical portion 612 and the space inside the inner cylindrical portion 612. (Step S106).

  Stirring in the stirring drum 613 is continued for a while after all the main materials and additives stored in the weighing hopper 41 have been transported into the stirring drum 613. Thereby, a main material and an additive are mixed uniformly. Thereafter, the control unit 10 stops the suction of the gas from the inside of the stirring drum 613, whereby the mixture of the main material and the additive spontaneously falls from the stirring drum 613 to the supply hopper 62, and the mixture becomes the molding machine 63. (Step S107).

<1-3. Configuration of weighing device>
Next, the detailed configuration of the weighing device 4 will be described. FIG. 3 is a schematic sectional view of the weighing device 4. FIG. 4 is a perspective view of the weighing hopper 41. FIG. 5 is a partial cross-sectional view of the weighing hopper 41 and the suction nozzle 43. FIG. 3 and FIG. 5 show a state where the powder P is stored in the weighing hopper 41.

  As shown in FIGS. 3 and 4, the weighing hopper 41 has a main storage portion 71, a sub storage portion 72, a supply port 73, a communication port 74, and a nozzle insertion port 75.

  In the main storage part 71, the granular material P is stored temporarily. The upper end portion of the main storage portion 71 is a supply port 73 to which the granular material P is supplied from the material supply portion 2. Further, the lower end portion of the main storage portion 71 is a communication port 74 that allows the main storage portion 71 and the sub storage portion 72 to communicate with each other. The main storage portion 71 includes a cylindrical portion 711 that extends in a cylindrical shape in the vertical direction, and a reduction portion 712 that squeezes downward toward the lower side of the cylindrical portion 711. Thereby, the granular material P stored in the main storage part 71 goes to the communication port 74 without remaining in the main storage part 71. As a result, when the granular material P is transported to the granular material transport destination 6, it is suppressed that the granular material remains in the weighing hopper 41.

  In the auxiliary storage part 72, the granular material P is stored secondary. The sub storage part 72 of this embodiment extends along the wall surface of the reduction part 712 of the main storage part 71. The sub-reservoir 72 is supplied with the granular material P from the main reservoir 71 through the communication port 74 by natural fall. An opening at the upper end of the sub-reservoir 72 is a nozzle insertion port 75.

  A part of the suction nozzle 43 including the suction port 431 is housed in the sub-reservoir 72 and at a position where it does not come into contact with the weighing hopper 41. By arranging the suction nozzle 43 at a position where it does not come into contact with the weighing hopper 41, the weight of the suction nozzle 43 is not added when the weight of the weighing hopper 41 is measured by the weighing scale 42.

  Here, FIG. 6 is a schematic cross-sectional view of a weighing device 4A of another example (comparative example) in which the weighing hopper and the nozzle do not contact each other. When the weighing hopper 41A has a single storage part 70A as in the weighing device 4A, the suction port 431A of the suction nozzle 43A is stored in order to suck the granular material in the storage part 70A without remaining. It is necessary to arrange in the vicinity of the lower end of the portion 70A. If it does so, the load of the granular material P will be applied on 43 A of suction nozzles, or the contact area of 43 A of suction nozzles and the granular material P will become large. Therefore, when measuring the weight of the granular material P stored in the weighing hopper 41A, a measurement error is likely to occur.

  On the other hand, in the weighing hopper 41 of this embodiment, the suction nozzle 43 is accommodated in the sub-reservoir 72. For this reason, when the granular material P is stored in the weighing hopper 41, the contact area between the suction nozzle 43 and the granular material P is reduced, or the suction nozzle 43 and the granular material P are not brought into contact with each other. Can do. Thereby, when measuring the weight of the granular material P stored in the inside of the measurement hopper 41, a measurement error can be suppressed.

  As shown in FIGS. 3 and 4, a part of the plate-like member constituting the reducing portion 712 of the weighing hopper 41 is a blocking portion 76 that divides into a main storage portion 71 and a sub storage portion 72. That is, the weighing hopper 41 has a blocking unit 76 that divides the space inside the weighing hopper 41 into a main storage unit 71 and a sub storage unit 72. With this configuration, a part of the member constituting the main reservoir 71 and a part of the member constituting the auxiliary reservoir 72 are common. Accordingly, the weighing hopper 41 having the main storage portion 71 and the sub storage portion 72 can be manufactured with a simple configuration.

  In the present embodiment, the blocking part 76 is disposed above the nozzle 43. Thereby, it is suppressed that the granular material P is loaded on the nozzle 43 in the sub-storage part 72. Therefore, when measuring the weight of the granular material P stored in the weighing hopper 41, the load of the granular material P is applied to the nozzle 43, and the occurrence of a measurement error is suppressed.

  The space inside the sub storage part 72 includes a natural filling part 721 and a nozzle arrangement part 722. The natural filling part 721 is a part of the auxiliary storage part 72 that is filled with the granular material P that has moved from the main storage part 71 by gravity. That is, the natural filling part 721 is a part defined by the angle of repose of the granular material supplied to the weighing hopper 41. Note that, in the above-described powder particle transporting process, the main powder particle P supplied into the weighing hopper 41 is the main material, so the natural filling portion 721 in the present embodiment is defined by the angle of repose of the main material. The part to be Specifically, in the sub-reservoir 72, a region below the virtual plane that extends from the edge of the communication port 74 along the angle of repose becomes the natural filling portion 721.

  The nozzle arrangement part 722 is a part other than the natural filling part 721 in the internal space of the auxiliary storage part 72. That is, the nozzle insertion port 75 is provided at the upper end of the nozzle arrangement portion 722. In the present embodiment, the nozzle arrangement part 722 extends obliquely upward from the natural filling part 721 along the outer wall surface of the reduction part 712 of the main storage part 71. For this reason, the angle with respect to the horizontal of the suction nozzle 43 between the suction port 431 and the nozzle insertion port 75 is 45 ° or more. As described above, the nozzle arrangement part 722 extends upward from the boundary 723 with the natural filling part 721, so that the granular material supplied to the auxiliary storage part 72 is suppressed from jumping out from the nozzle insertion port 75. .

  In the present embodiment, the suction port 431 is disposed in the vicinity of the boundary 723 between the natural filling portion 721 and the nozzle placement portion 722. Thereby, when the granular material P is stored in the weighing hopper 41, the contact area between the suction nozzle 43 and the granular material P is further reduced, or the suction nozzle 43 and the granular material P are not brought into contact with each other. be able to. Thereby, when measuring the weight of the granular material P stored in the inside of the measurement hopper 41, the measurement error can be further suppressed.

  When the granular material P is transported from the weighing hopper 41 to the granular material transport destination 6, the gas in the suction nozzle 43 is sucked into the transport pipe 5. At this time, as indicated by an arrow in FIG. 5A, the outside of the weighing hopper 41 is directed into the auxiliary reservoir 72 via the nozzle insertion port 75, and the periphery of the suction nozzle 43 is along the suction nozzle 43. After moving downward and changing direction near the suction port 431, an air flow F is generated from the suction port 431 toward the inside of the suction nozzle 43.

  Here, “near the boundary 723” is a range in which the powder P is subjected to the action of the airflow F. By arranging the suction port 431 in the vicinity of the boundary 723, the granular material P hardly disturbs the air flow F, and the air flow F easily acts on the granular material P. Therefore, the granular material P can be efficiently transported from the weighing hopper 41 to the granular material transport destination 6. The suction port 431 may be disposed at a position overlapping the boundary 723 or may be disposed in the natural filling part 721. Even in that case, if the suction port 431 is disposed in the vicinity of the boundary 723, the powder P is unlikely to interfere with the air flow F, and the air flow F is likely to act on the powder P.

  In the present embodiment, in particular, the suction port 431 is disposed in the nozzle arrangement portion 722. That is, the suction nozzle 43 does not contact the powder P in the normal state shown in FIGS. If it does in this way, when the granular material P was supplied to the measurement hopper 41, the granular material P was vigorously thrown in, and the granular material P was supplied to the upper side rather than the boundary 723 in the auxiliary storage part 72. Even in this case, the contact area between the suction nozzle 43 and the granular material P can be made sufficiently small as shown in FIG. Thereby, when measuring the weight of the granular material P stored in the inside of the measurement hopper 41, the measurement error can be further suppressed. Moreover, the granular material P does not easily disturb the airflow F, and the airflow F is likely to act on the granular material P.

  Further, in the structure of the present embodiment, even if the positional relationship between the weighing hopper 41 and the suction nozzle 43 is slightly deviated, the cross-sectional area of the entire path of the air flow F in the sub-storage part 72 does not change. For this reason, the inflow amount of the gas flowing into the suction nozzle 43 is unlikely to change. Therefore, even when the weighing hopper 41 is moved for maintenance or the like, it is not necessary to strictly adjust the positional relationship between the weighing hopper 41 and the suction nozzle 43. That is, it is possible to suppress the measurement error while reducing the labor for adjusting the position of the member.

<2. Modification>
Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.

  FIG. 7 is a schematic cross-sectional view of a weighing device 4B according to a modification. The weighing hopper 41B of the weighing device 4B has a main storage part 71B in which the powder particles are temporarily stored and a sub storage part 72B in which the powder particles are stored secondarily. In the example of FIG. 7, the main storage portion 71B of the weighing hopper 41B has a cylindrical portion 711B that extends in a cylindrical shape in the up-down direction, a reduction portion 712B that shrinks downward toward the bottom below the cylindrical portion 711B, and a reduction. Below the part 712B, it has the lower cylinder part 714B extended cylindrically in the up-down direction. And the lower end part of the lower cylinder part 713B is the communication port 74B which connects the main storage part 71B and the sub storage part 72B.

  The sub-storage part 72B has a natural filling part 721B extending obliquely downward from the communication port 74B, and a nozzle arrangement part 722B extending substantially vertically upward from a portion that does not overlap with the communication port 74B of the natural filling part 721B. A nozzle insertion port 75B is provided at the upper end of the nozzle arrangement portion 722B.

  As described above, in the example of FIG. 7, the nozzle arrangement portion 722 </ b> B extends from the boundary 723 </ b> B with the natural filling portion 721 </ b> B substantially upward in the vertical direction, so Jumping out from the mouth 75B is effectively suppressed.

  FIG. 8 is a schematic cross-sectional view of a weighing device 4C according to another modification. The weighing hopper 41C of the weighing device 4C includes a main storage portion 71C in which powder particles are temporarily stored, and two sub storage portions 72C in which powder particles are secondarily stored. The two auxiliary storage parts 72C are arranged side by side in the up-down direction. A suction nozzle 43C is disposed inside each of the two auxiliary storage portions 72C.

  FIG. 9 is a perspective view of a weighing hopper 41D according to another modification. The weighing hopper 41D has a main storage part 71D in which the powder particles are temporarily stored and three sub storage parts 72D in which the powder particles are stored secondarily. A suction nozzle is disposed inside each of the three sub-storage portions 72D.

  In the example of FIGS. 8 and 9, the weighing hopper has a plurality of sub-storage parts. In this way, the weighing hopper that handles a single granular material may have a plurality of sub-reservoir parts in order to transport from a single weighing hopper to a plurality of destinations. Since the weighing hopper has a sub-reservoir for each of a plurality of suction nozzles corresponding to a plurality of destinations, the suction nozzle and the powder particles are brought into contact with each other so that the powder particles stored in the weighing hopper Weighing errors that occur when weighing can be suppressed.

  Further, the detailed shape of the weighing device may be different from the shape shown in each drawing of the present application.

  Moreover, you may combine suitably each element which appeared in said embodiment and modification in the range which does not produce inconsistency.

DESCRIPTION OF SYMBOLS 1 Powder transport system 2 Material supply part 3 Airflow generation part 4,4A, 4B, 4C Metering device 5 Transport piping 10 Control part 21 1st material supply part 22 2nd material supply part 31 Suction blower 32 Exhaust pipe 33 Switching part 41, 41A, 41B, 41C, 41D Weighing hopper 42 Weigh scale 43, 43A, 43C Suction nozzle 431, 431A Suction port 6 Particulate transport destination 61 Airflow stirring device 62 Supply hopper 63 Molding machine 70A Reservoir 71, 71B, 71C , 71D Main storage part 72, 72B, 72C, 72D Sub storage part 721, 721B Natural filling part 722, 722B Nozzle arrangement part 723, 723B Boundary 73 Supply port 74, 74B Communication port 75, 75B Nozzle insertion port 76 Blocking part F Airflow P Powder and granular material

Claims (6)

A storage tank for storing powder particles;
Weighing means for weighing the mass of the granular material stored in the storage tank;
One end is a suction port arranged inside the storage tank, and the other end is connected to a transport pipe for suction transport; and
Have
The storage tank is
A main reservoir in which the particles are primarily stored;
A sub-reservoir in which the granular material is secondarily stored; and
A communication port communicating the main storage part and the sub-storage part;
A nozzle insertion port communicating the sub-storage part and the outside;
Have
The powder is supplied to the sub-storage part by gravity from the main storage part through the communication port,
Part of the nozzle including the suction port is disposed in the sub-reservoir and at a position not in contact with the reservoir. The weighing device according to claim 1,
The storage tank further has a blocking part,
The space inside the storage tank is a weighing device that is divided into the main storage unit and the sub storage unit by the blocking unit. A metering device according to claim 1 or claim 2,
The communication port is a weighing device arranged at a lower end portion of the main storage portion. A weighing device according to claim 3,
The main storage portion is a weighing device in which at least a part including the lower end portion is recessed as it goes downward. A weighing device according to any one of claims 1 to 4,
The sub-reservoir is
A natural filling portion filled with the granular material supplied by gravity from the main storage portion;
The nozzle is arranged inside, and a nozzle arrangement part extending upward from the natural filling part,
Including
The nozzle insertion port is provided in the nozzle arrangement portion,
The metering device, wherein the suction port of the nozzle is disposed near a boundary between the natural filling portion and the nozzle placement portion. A weighing device according to any of claims 1 to 5,
The transport pipe for suction transport, one end of which is connected to the nozzle;
A suction device for sucking the gas inside the transport pipe;
Connected to the other end of the transport pipe,
A granular material transport device.

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