Weighing and mixing device

Abstract

To provide a weighing and mixing device capable of reducing the cleaning work when a raw material to be weighed is changed.SOLUTION: A weighing and mixing device 1 includes a weighing part 13 for weighing a raw material contained in a weighing container 21, a main supply part 31 for supplying the raw material to the weighing container 21, an external supply part 81 for supplying a raw material of a type different from that supplied by the body supply part 31 to the weighing part 13, an intake pipe 64 to which an external supply part 81 is connected, an intake part 61 for introducing the raw material supplied by the external supply part 81 into the weighing container 21 through the intake pipe 64 without retention, and a control unit for controlling each supply operation of the body supply part 31 and the external supply part 81 so that the weighing unit 13 weighs a predetermined amount of each of the multiple types of raw materials.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a measuring and mixing device that measures and mixes a plurality of types of raw materials. [Background technology]

[0002] For example, in the manufacturing process of resin molded products, the powdered and granular materials that are the raw materials for the resin molded products, such as plastic pellets, crushed materials, master batches (pelletized pigments), and additives, are mixed in fixed amounts, and the molding material consisting of the mixed powdered and granular materials is then supplied to a molding machine.

[0003] A measuring and mixing device is used to mix fixed amounts of multiple types of powdered and granular materials. In one example of the measuring and mixing device, multiple supply hoppers are provided, and a raw material tank installed outside the measuring and mixing device is connected to the supply hoppers in a one-to-one relationship, and the powdered and granular materials (raw materials) stored in the raw material tank are transported to the supply hoppers. A screw feeder is connected to the supply hopper, and the powdered and granular materials are discharged from the supply hopper toward the weighing hopper by the operation of the screw feeder. The powdered and granular materials from the multiple weighing hoppers are sequentially received by the weighing hopper, and a fixed amount of each powdered and granular material is measured by the weighing hopper. The powdered and granular materials are then transferred from the weighing hopper to a mixing drum, mixed in the mixing drum, transported from the mixing drum to a loader hopper, and supplied from the loader hopper to a molding machine. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-64119 A Summary of the Invention [Problem to be solved by the invention]

[0005] For example, when changing the masterbatch contained in the molding material, that is, when changing the color, the raw material tank is disconnected from the supply hopper and another raw material tank is connected to the supply hopper. If the original masterbatch remains in the supply hopper or the screw feeder and is mixed with a masterbatch newly transported from another raw material tank to the supply hopper, and the molding material containing the mixed masterbatch is supplied to the molding machine, the resin molded product will have a color shift defect. Therefore, before connecting another raw material tank to the supply hopper, the supply hopper and the screw feeder must be thoroughly cleaned to completely remove the original masterbatch from them.

[0006] However, thorough cleaning of the supply hopper and screw feeder is a very time-consuming task and places a heavy burden on the worker.

[0007] An object of the present invention is to provide a measuring and mixing device that can reduce the effort of cleaning when changing the raw material to be measured. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, a measuring and mixing device according to one aspect of the present invention includes a measuring unit that measures raw materials contained in a measuring container, a first supply unit that supplies the raw materials to the measuring container, a second supply unit that supplies a type of raw material different from the raw material to be supplied by the first supply unit to the measuring unit, an input unit that has an input pipe to which the second supply unit is connected and inputs the raw material supplied by the second supply unit through the input pipe into the measuring container without allowing it to remain, and a control unit that controls the supply operations of the first supply unit and the second supply unit so that the measuring unit measures each fixed amount of multiple types of raw materials.

[0009] According to this configuration, the raw material is supplied to the measuring container of the measuring unit by the first supply unit. Also, the input unit has an input pipe connected to the second supply unit, and the raw material supplied by the second supply unit is input to the measuring container through the input pipe.

[0010] When changing the raw material supplied by the second supply unit, the original raw material is removed from the input unit, so that the original raw material and the new raw material after the change can be prevented from mixing in the input unit without cleaning the input unit or by simply cleaning the input unit. Furthermore, by configuring the input unit to input the raw material supplied by the second supply unit into the measuring container through the input tube without allowing it to remain there, the effort required for cleaning to remove the original raw material from the input unit can be reduced.

[0011] The input pipe may have a straight pipe section extending vertically upward, and an inlet pipe section having one end connected to the straight pipe section and the other end opening obliquely downward with respect to the vertical direction.

[0012] This configuration can prevent the raw material from stagnation in the introduction pipe.

[0013] A purge port may be provided at the upper end of the inlet pipe section to introduce air into the pipe to purge the raw material from the input pipe.

[0014] In this configuration, air can be introduced into the input tube from the purge port, and the raw material can be actively purged from the input tube by the air. This allows the raw material to be effectively purged from the input tube even if it is attached to the inner surface of the input tube by electrostatic adhesion, and further prevents the original raw material from mixing with the new raw material after the change in the input section.

[0015] The inlet pipe section may be curved convexly upward from a straight pipe section, and the purge port may be provided at an upper end of the convexly curved inlet pipe section.

[0016] The input section has a side wall that tapers downward and a top plate that closes the upper end of the side wall, and the lower end of the side wall opens toward the measuring container, and the input tube is connected to the top plate and may be in communication with the space surrounded by the side wall.

[0017] In this configuration, the raw material supplied by the second supply unit passes through the input pipe and falls from the input pipe into the space surrounded by the side wall. Since the side wall has a shape that narrows downward, the raw material received by the side wall does not remain on the inner surface of the side wall, but flows down along the inner surface of the side wall and is input into the measuring container from the opening at the lower end of the side wall. This makes it possible to prevent the raw material from accumulating on the inner surface of the side wall.

[0018] The control unit may control each of the supply operations of the first supply unit and the second supply unit so that, in measuring one batch of multiple types of raw materials, the supply operation of the first supply unit is performed intermittently in multiple steps, and the supply operation of the second supply unit is performed between the supply operation of the first supply unit and the next supply operation.

[0019] With this control, the raw material supplied by the second supply unit is sandwiched between the raw material supplied by the first supply unit from above and below inside the measuring container. In a configuration in which a discharge port for discharging the raw material is formed at the bottom of the measuring container, the raw material is discharged from the discharge port in this state, thereby preventing the raw material supplied by the second supply unit from remaining inside the measuring container.

[0020] The multiple types of raw materials discharged from the measuring containers are mixed in the mixer, so that the multiple types of raw materials, i.e., the raw materials supplied by the first supply section and the second supply section, can be mixed evenly.

[0021] The control unit may control the supply operation of the first supply unit while referring to the measurement value by the measuring unit, and may stop the supply operation of the first supply unit when the amount of raw material supplied by the first supply unit to the measuring container reaches a set amount.

[0022] Furthermore, the control unit may stop the supply operation of the second supply unit when a set time has elapsed since the start of the supply operation of the second supply unit.

[0023] A configuration is also conceivable in which the amount of the raw material to be supplied by the second supply unit to the measuring container is calculated based on the measurement value by the measuring unit, and the supply operation of the second supply unit is stopped when the amount of the raw material to be supplied by the second supply unit reaches a set amount. However, if the amount of the raw material to be supplied by the second supply unit is small, there is a risk that the raw material to be supplied by the second supply unit will be supplied to the measuring container after the supply operation of the second supply unit is stopped, and thus more raw material than the fixed amount will be supplied to the measuring container. By stopping the supply operation of the second supply unit when a set time has elapsed since the start of the supply operation of the second supply unit, it is possible to prevent the raw material to be supplied by the second supply unit from being excessively supplied to the measuring container.

[0024] However, if the supply operation of the second supply unit is controlled over time, it is unclear whether a fixed amount of the raw material to be supplied by the second supply unit has actually been supplied to the measuring container, and there is a risk of unevenness in the amount of raw material to be supplied by the second supply unit.

[0025] Therefore, it is preferable that the control unit, after the supply operation of the second supply unit is stopped, calculates the amount of raw material supplied to the measuring container by the supply operation of the second supply unit from the measurement value by the measuring unit, and corrects the set time based on a comparison between the calculated amount and the fixed amount to be supplied to the measuring container by the supply operation of the second supply unit. Furthermore, in a configuration in which the set time is corrected, when the fixed amount to be supplied to the measuring container by the supply operation of the second supply unit is changed, the set time is automatically changed by correction, which saves the user the trouble of setting the set time.

[0026] The metering and mixing device may be provided with a plurality of second supply units, the input unit may include a plurality of input pipes, and the second supply units may be connected to the input pipes in a one-to-one relationship.

[0027] In addition, the metering and mixing device may be provided with a plurality of second supply units, the input unit may include a single input pipe, and the second supply units may be selectively connected to the input pipe.

[0028] The raw material to be supplied by the first supply unit may be a main material that is supplied in a relatively large amount to the measuring container, and the raw material to be supplied by the second supply unit may be a minor material that is supplied in a relatively small amount to the measuring container.

[0029] When the raw material to be supplied by the second supply unit is a small amount of material, the second supply unit may include an ejector for pneumatically transporting the raw material. Effect of the Invention

[0030] According to the present invention, it is possible to reduce the effort of cleaning when changing the raw material to be weighed. [Brief description of the drawings]

[0031] [Figure 1] 1 is a diagram illustrating a configuration of a metering and mixing device according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view showing the internal and external configuration of the upper housing of the measuring and mixing device, with the top plate of the upper housing removed and the front door open. [Diagram 3] FIG. 2 is a side view (view from the side) of the insertion section. [Figure 4] FIG. 2 is a plan view of the input section (viewed from above). [Diagram 5] FIG. 2 is a block diagram showing the electrical configuration of the metering and mixing device. [Figure 6] 10 is a flowchart showing the flow of a raw material measuring process. [Figure 7] 11 is a flowchart showing the flow of a first main material weighing process. [Figure 8] 13 is a flowchart showing the flow of a small amount material weighing process. [Figure 9] 13 is a flowchart showing the flow of a second main material weighing process. [Figure 10] 13 is a flowchart showing a flow of a set time correction process. [Figure 11] 13 is a flowchart showing another example of the raw material measuring process. [Figure 12]13 is a flowchart showing yet another example of the raw material measuring process. [Figure 13] FIG. 10 is a diagram illustrating the configuration of a measuring and mixing device according to another embodiment of the present invention. [Figure 14] FIG. 13 is a side view showing a modified example of the insertion section. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0033] <Configuration of the metering and mixing device> FIG. 1 is a diagram illustrating the configuration of a measuring and mixing device 1 according to one embodiment of the present invention.

[0034] The measuring and mixing device 1 is a device that measures and mixes various powder and granular materials such as plastic pellets, pulverized materials, master batches, and additives, which are raw materials for plastic products.

[0035] The measuring and mixing device 1 comprises an upper housing 11 and a lower housing 12. The upper housing 11 and the lower housing 12 are stacked one on top of the other. The upper housing 11 is provided with a measuring section 13 capable of measuring the respective fixed amounts of a plurality of types of powdered or granular materials, and a mixing section 14 capable of mixing the plurality of types of powdered or granular materials whose respective fixed amounts have been measured by the measuring section 13. The lower housing 12 is provided with a mixed material storage section 15 capable of storing the plurality of types of powdered or granular materials mixed by the mixing section 14.

[0036] FIG. 2 is a perspective view showing the internal and external configuration of upper housing 11. As shown in FIG.

[0037] The upper housing 11 is formed in a substantially rectangular parallelepiped shape, and has a front door 16 that opens and closes the front side.

[0038] As shown in FIG. 1, the weighing section 13 includes a weighing container 21 and a load cell 22. As shown in FIG. 2, the upper end of the weighing container 21 opens upward as an inlet 23. The weighing container 21 is formed in a shape that narrows downward. The lower end of the weighing container 21 opens downward as a discharge outlet. The weighing container 21 is provided with, for example, a gate shutter 24 as an opening / closing mechanism for opening and closing the discharge outlet. When a powdered or granular material is put into the weighing container 21 from the inlet 23 with the discharge outlet closed, the powdered or granular material is stored (reserved) in the weighing container 21. The load cell 22 outputs an electric signal (voltage) according to the combined mass of the weighing container 21 itself and the powdered or granular material stored in the weighing container 21. The mass of the powdered or granular material stored in the weighing container 21 can be obtained from the change in the electric signal output by the load cell 22.

[0039] A plurality of types of powdered or granular materials are sequentially fed into the measuring container 21 through the feed port 23, and the mass of each powdered or granular material contained in the measuring container 21 is measured. Then, by containing fixed amounts of each of the plurality of types of powdered or granular materials in the measuring container 21, the plurality of types of powdered or granular materials are blended in a predetermined ratio (proportion). When the discharge port of the measuring container 21 is opened, the plurality of types of powdered or granular materials blended in the predetermined ratio are discharged from the discharge port by their own weight.

[0040] The mixing section 14 includes a mixing drum 25. The mixing drum 25 is disposed below the measuring container 21 of the measuring section 13, and has a bottom plate inclined downward toward the front with respect to the vertical direction, and a side wall 26 rising from the periphery of the bottom plate. A part of the opening surrounded by the upper end of the side wall 26 is covered with a lid 27, and the part of the opening not covered by the lid 27 is provided as a receiving port 28 that opens toward the discharge port of the measuring container 21. A discharge port that opens toward the bottom is provided at the lower end of the mixing drum 25. The mixing drum 25 is provided with, for example, a flap valve as an opening / closing mechanism for opening and closing the discharge port. An agitator (not shown) is also provided inside the mixing drum 25. The agitator is supported by a rotating shaft that extends in a direction perpendicular to the bottom plate of the mixing drum 25, and is rotated by the power of a motor coupled to the rotating shaft.

[0041] When multiple types of powdered granular materials are discharged from the discharge port of the measuring container 21 with the discharge port of the mixing drum 25 closed, the powdered granular materials are received into the mixing drum 25 through the receiving port 28 of the mixing drum 25, and the multiple types of powdered granular materials are stored in the mixing drum 25. When the multiple types of powdered granular materials are stored in the mixing drum 25, the multiple types of powdered granular materials are mixed by rotating the agitator. When the multiple types of powdered granular materials are sufficiently mixed, the discharge port of the mixing drum 25 is opened, and the mixed multiple types of powdered granular materials (hereinafter referred to as "mixed material") are discharged from the discharge port.

[0042] The mixed material storage section 15 is disposed below the mixing section 14. The mixed material storage section 15 is equipped with a source hopper (not shown). An upper end of the source hopper is provided with a receiving port that opens toward the discharge port of the mixing drum 25. The lower part of the source hopper is formed in a funnel shape (for example, a substantially conical shape) that narrows downward. The lower end of the source hopper opens downward as a discharge port. The source hopper is provided with an opening / closing mechanism that opens and closes the discharge port.

[0043] When the discharge port of the source hopper is closed and the mixed material is discharged from the mixing drum 25 of the mixer 14, the mixed material is received into the source hopper through the receiving port of the source hopper, and the mixed material is stored in the source hopper.

[0044] The measuring and mixing device 1 is provided with three main body supply units 31A, 31B, and 31C each capable of supplying raw materials for plastic products, such as plastic pellets, crushed materials, or additives, to the measuring container 21 of the measuring unit 13. The three main body supply units 31A, 31B, and 31C have the same configuration. Hereinafter, when there is no need to distinguish between the three main body supply units 31A, 31B, and 31C, they will be collectively referred to as "main body supply unit 31."

[0045] 2, the main supply unit 31 includes a supply hopper 32. The lower portion of the supply hopper 32 is formed in a shape that narrows downward. A screw feeder 33 that feeds raw material from the supply hopper 32 is provided at the lower end of the supply hopper 32.

[0046] The screw feeder 33 has a known configuration, and includes, for example, a cylinder 34, a supply screw (not shown), and a supply motor 35. One end of the cylinder 34 is connected to an opening provided at the lower end of the supply hopper, and the inside of the cylinder 34 communicates with the inside of the supply hopper 32 through the opening. The other end of the cylinder 34 is a discharge port. The supply screw extends on the center line of the cylinder 34. The supply motor 35 is coupled to the other end of the supply screw. When the supply motor 35 is driven, the supply screw rotates. The rotation of the supply screw sends the raw material from the supply hopper 32 to the cylinder 34, and the raw material is sent through the cylinder 34 toward the discharge port, and the raw material is cut out from the discharge port. The cylinder 34 may be provided with an opening / closing damper 36 that opens the discharge port when the supply screw rotates and closes the discharge port when the supply screw stops.

[0047] In order to supply raw materials to the supply hopper 32 of the main supply section 31, and to transport the mixed material from the mixed material storage section 15 to the destination hopper 41, the metering and mixing device 1 is equipped with a primary / secondary switching valve 42, primary transport pipes 43A, 43B, 43C, primary suction pipes 44A, 44B, 44C, secondary transport pipe 45, secondary suction pipe 46, a blower 47, and a negative pressure pipe 48, as shown in FIG. 1.

[0048] The destination hopper 41 is provided above the injection molding machine 2, which is the destination of the mixed material. The destination hopper 41 has a cylindrical side wall 51 and a top plate 52 that closes the upper end of the side wall 51. The lower part of the side wall 51 is formed in a shape that narrows downward. The lower end of the destination hopper 41 opens toward the internal space of the injection molding machine 2 as a discharge port.

[0049] The primary-secondary switching valve 42 has first, second and third primary input ports, a secondary input port and an output port. The primary-secondary switching valve 42 is provided with valve bodies that individually open and close the first, second and third primary input ports and the secondary input port. The primary-secondary switching valve 42 is switched between first, second and third primary transport positions and a secondary transport position depending on the positions of the valve bodies. In the first primary transport position, the secondary input port is closed and the first primary input port is opened, and the first primary input port and the output port are communicated in the valve box. In the second primary transport position, the secondary input port is closed and the second primary input port is opened, and the second primary input port and the output port are communicated in the valve box. In the third primary transport position, the secondary input port is closed and the third primary input port is open, so that the third primary input port communicates with the output port in the valve body. In the secondary transport position, the first, second and third primary input ports are closed and the secondary input port is open, so that the secondary input port communicates with the output port in the valve body.

[0050] 2, a transport pipe connection part 54 that connects the inside and outside of the supply hopper 32 is provided on the top plate 53 of the supply hopper 32 of the main supply unit 31. One end of the primary transport pipe 43A is connected to the transport pipe connection part 54 of the supply hopper 32A. One end of the primary transport pipe 43B is connected to the transport pipe connection part 54 of the supply hopper 32B. One end of the primary transport pipe 43C is connected to the transport pipe connection part 54 of the supply hopper 32C. The other ends of the primary transport pipes 43A, 43B, and 43C are each disposed in raw materials stored in a different raw material tank.

[0051] A suction pipe connection 55 that connects the inside and outside of the supply hopper 32 is provided on the top plate 53 of the supply hopper 32. One end of the primary suction pipe 44A is connected to the suction pipe connection 55 of the supply hopper 32A. One end of the primary suction pipe 44B is connected to the suction pipe connection 55 of the supply hopper 32B. One end of the primary suction pipe 44C is connected to the suction pipe connection 55 of the supply hopper 32C. The other ends of the primary suction pipes 44A, 44B, 44C are connected to the first, second, and third primary input ports of the primary / secondary switching valve 42, respectively.

[0052] One end of the secondary transport pipe 45 is connected to the discharge port of the source hopper of the mixed material storage section 15. As shown in Fig. 1, a transport pipe connection part 56 that connects the inside and outside of the destination hopper 41 is provided on the side wall 51 of the destination hopper 41. The other end of the secondary transport pipe 45 is connected to the transport pipe connection part 56.

[0053] A suction pipe connection part 57 that connects the inside and outside of the destination hopper 41 is provided on the top plate 52 of the destination hopper 41. One end of the secondary suction pipe 46 is connected to the suction pipe connection part 57. The other end of the secondary suction pipe 46 is connected to the secondary input port of the primary / secondary switching valve 42.

[0054] The blower 47 has an inlet and an outlet.

[0055] One end of the negative pressure pipe 48 is connected to the output port of the primary / secondary switching valve 42. The other end of the negative pressure pipe 48 is connected to the suction port of the blower 47.

[0056] When raw materials are supplied from the raw material tank to the supply hopper 32A of the main supply unit 31, the primary / secondary switching valve 42 is set to the first primary transport position. When the blower 47 is driven, negative pressure is generated in the negative pressure pipe 48, the valve box of the primary / secondary switching valve 42, and the primary suction pipe 44A. Due to this negative pressure, the raw materials in the raw material tank are supplied to the supply hopper 32A through the primary transport pipe 43A.

[0057] When raw materials are supplied from the raw material tank to the supply hopper 32B of the main supply unit 31, the primary-secondary switching valve 42 is set to the second primary transport position. When the blower 47 is driven, negative pressure is generated in the negative pressure pipe 48, the valve box of the primary-secondary switching valve 42, and the primary suction pipe 44B. Due to this negative pressure, the raw materials in the raw material tank are supplied to the supply hopper 32B through the primary transport pipe 43B.

[0058] When raw materials are supplied from the raw material tank to the supply hopper 32C of the main supply unit 31, the primary-secondary switching valve 42 is set to the third primary transport position. When the blower 47 is driven, negative pressure is generated in the negative pressure pipe 48, the valve box of the primary-secondary switching valve 42, and the primary suction pipe 44C. Due to this negative pressure, the raw materials in the raw material tank are supplied to the supply hopper 32C through the primary transport pipe 43C.

[0059] When the mixed material is transported from the source hopper of the mixed material storage section 15 to the destination hopper 41, the primary-secondary switching valve 42 is set to the secondary transport position. Then, the blower 47 is driven. When the blower 47 is driven, negative pressure is generated in the negative pressure pipe 48, the valve box of the primary-secondary switching valve 42, and the secondary suction pipe 46. Due to the negative pressure, an airflow from the source hopper toward the destination hopper 41 is generated in the secondary transport pipe 45. When the discharge port of the source hopper is opened, the mixed material is discharged from the discharge port of the source hopper into the secondary transport pipe 45. Then, the mixed material is transported by the airflow through the secondary transport pipe 45 toward the destination hopper 41, and is supplied from the secondary transport pipe 45 to the destination hopper 41.

[0060] The measuring and mixing device 1 also includes an input section 61 .

[0061] Fig. 3 is a side view (viewed from the side) of the insertion unit 61. Fig. 4 is a plan view (viewed from above) of the insertion unit 61.

[0062] The feeding section 61 is disposed at the top of the upper housing 11. The feeding section 61 includes a feeding hopper 62, an introduction pipe 63, and a feeding pipe 64.

[0063] The input hopper 62 has a funnel-shaped side wall 65 that narrows downward, and a top plate 66 that closes the upper end of the side wall 65. The lower end of the side wall 65 opens downward.

[0064] A circular external input port 68 is provided on the top plate 67 of the upper housing 11 at a position facing from above the input port of the weighing container 21 of the weighing section 13. The introduction pipe 63 is formed in a circular tube shape, and one end is connected to an opening at the lower end of the input hopper 62 and is inserted into the external input port 68. As a result, the inside of the input hopper 62 and the inside of the weighing container 21 are in communication with each other via the introduction pipe 63.

[0065] The introduction pipe 63 may be formed in a circular tube shape having an inner diameter corresponding to the diameter of the external input port 68, and may be provided on the inner surface of the top plate 67 of the upper housing 11 so as to extend downward from the periphery of the external input port 68 toward the inside of the weighing container 21. In this case, the input hopper 62 is attached to the upper surface of the top plate 67 of the upper housing 11 with the opening at the lower end of the side wall 65 aligned with the external input port 68.

[0066] 3 and 4, the side wall 65 is formed in a substantially conical shape, and the top plate 66 is formed in a circular shape in a plan view. An air vent port 71 for venting air from the internal space of the feeding hopper 62 is provided in the center of the top plate 66. Furthermore, as shown in FIG. 4, the top plate 66 is provided with four connection ports 72 at equal angular intervals around the center line of the top plate 66, that is, at 90° intervals. Each connection port 72 penetrates the top plate 66.

[0067] 3 and 4, four input pipes 64 are provided in the input section 61. The input pipes 64 integrally include a straight pipe section 73 and an inlet pipe section 74. The straight pipe section 73 extends upward from the top plate 66 of the input hopper 62 in a vertical direction perpendicular to the top plate 66. One end of the inlet pipe section 74 is connected to the straight pipe section 73, and the other end opens obliquely downward relative to the vertical direction. In the configuration shown in FIG. 3, the inlet pipe section 74 is curved convexly upward and connected to the upper end of the straight pipe section 73 from above. A straight pipe section 73 is inserted into each connection port 72 on the top plate 66 of the feeding hopper 62, or the straight pipe section 73 is aligned so that the openings of the lower ends of the straight pipe section 73 overlap each connection port 72, and the straight pipe section 73 is connected to each connection port 72, so that the inside of each feeding pipe 64 is connected to the space surrounded by the side wall 65 of the feeding hopper 62, i.e., the inside of the feeding hopper 62.

[0068] A purge port 75 to which a purge air supply pipe for supplying air is connected is provided in the inlet pipe section 74. Preferably, the purge port 75 is provided at the upper end of the inlet pipe section 74, or at the upper end of the convexly curved portion in a configuration in which the upper end of the inlet pipe section 74 is curved upwardly.

[0069] 1, the metering and mixing device 1 includes a plurality of external supply units 81. The plurality of external supply units 81 are provided outside the upper housing 11.

[0070] The external supply unit 81 includes a raw material supply pipe 82, an ejector 83, a raw material tank 84, and a raw material introduction pipe 85. The external supply unit 81 is in one-to-one correspondence with the input pipe 64. One end of the raw material supply pipe 82 is connected to the other end of the inlet pipe section 74 of the input pipe 64 corresponding to the external supply unit 81 (see FIG. 3). One end of the raw material introduction pipe 85 is connected to the other end of the raw material supply pipe 82. The ejector 83 is interposed in the middle of the raw material supply pipe 82, and a compressor that supplies compressed air is connected to the ejector 83. The raw material tank 84 stores a small amount of material to be mixed in a small amount with a main material as a raw material for plastic products. The other end of the raw material introduction pipe 85 is connected to the raw material tank 84.

[0071] When compressed air from the compressor is supplied to the ejector 83, the inside of the raw material supply pipe 82 becomes negative pressure, and a small amount of material is sucked from the raw material tank 84 through the raw material introduction pipe 85 into the raw material supply pipe 82. The small amount of material is carried toward the input pipe 64 by the air flowing through the raw material supply pipe 82, and enters the input hopper 62 through the input pipe 64. The air and the small amount of material are separated in the input hopper 62, and the small amount of material falls from the opening at the bottom end of the input hopper 62 through the introduction pipe 63 and is input into the measuring container 21 of the measuring section 13, and the air is discharged to the outside of the input hopper 62 through the air vent 71. In this way, the input section 61 is configured to input the small amount of material supplied by the external supply section 81 into the measuring container 21 without retaining it.

[0072] In FIG. 1, four external supply units 81 are provided in the metering and mixing device 1, and the four external supply units 81 are connected to the four input pipes 64 in one-to-one correspondence.

[0073] FIG. 5 is a block diagram showing the electrical configuration of the measuring and mixing device 1.

[0074] The metering and mixing device 1 is equipped with a control unit 91.

[0075] The control unit 91 is provided with a CPU 92 and a memory 93 such as a flash memory or a dynamic random access memory (DRAM). The CPU 92 and the memory 93 may be built into a microcomputer (microcontroller).

[0076] The control unit 91 receives an electrical signal output from the load cell 22 of the weighing unit 13 .

[0077] The CPU 92 of the control unit 91 executes a program stored in the memory 93 to control the operation of each part of the weighing unit 13, the mixing unit 14, the mixed material storage unit 15, the main body supply unit 31, the primary / secondary switching valve 42, the blower 47 and the external supply unit 81, such as the operation of the opening and closing mechanisms of the weighing unit 13, the mixing unit 14 and the mixed material storage unit 15, the operation of the screw feeder of the main body supply unit 31, the operation of the primary / secondary switching valve 42, the operation of the blower 47 and the supply of compressed air to the ejector 83 of the external supply unit 81, based on electrical signals input to the control unit 91 from the load cell 22 of the weighing unit 13.

[0078] <Raw material weighing process> FIG. 6 is a flowchart showing the flow of the raw material measuring process.

[0079] In the measuring and mixing device 1, the CPU 92 of the control unit 91 executes a raw material measuring process for each batch. In the raw material measuring process, the supply operation of the main supply unit 31 and the supply operation of the external supply unit 81 are controlled, and one batch of raw materials (main material and minor material) mixed at a predetermined mixing ratio is stored in the measuring container 21 of the measuring unit 13. For example, plastic pellets are the main material in the raw materials of the plastic product, and are supplied to the measuring container 21 by the supply operation of the main supply unit 31A. For example, a master batch, which is a pelletized pigment, is the minor material in the raw materials of the plastic product, and when the raw materials of the plastic product contain one type of minor material, it is supplied to the measuring container 21 by the supply operation of any one of the external supply units 81. After the raw material measuring process, the raw materials mixed at a predetermined mixing ratio are supplied from the measuring container 21 to the mixing unit 14, and the raw materials are mixed in the mixing unit 14. Then, the mixed material obtained by mixing the raw materials mixed at the predetermined mixing ratio is supplied from the mixing unit 14 to the mixed material storage unit 15. The above operation is regarded as one batch operation, and this batch operation is performed a predetermined number of times. After that, at a predetermined timing, the mixed material is transported from the mixed material storage unit 15 to the destination hopper 41, and the mixed material is supplied from the destination hopper 41 to the injection molding machine 2.

[0080] In the raw material measuring process, first, the main supply unit 31 performs a first supply operation, and a first set amount of the main material is supplied to the measuring container 21 of the measuring unit 13 by the supply operation (step S1: first main material measuring process). The first set amount is set to, for example, half the fixed amount (required amount) of the main material for one batch.

[0081] Next, a supply operation of the external supply unit 81 is performed, and by this supply operation, a fixed amount of small amount of material is supplied to the measuring container 21 of the measuring unit 13 through the input unit 61 (step S2: small amount material measuring process).

[0082] Thereafter, a second supply operation of the main supply unit 31 is performed, and by this supply operation, the remaining second set amount of main material, which is obtained by subtracting the first set amount from the fixed amount of main material, is supplied to the measuring container 21 of the measuring unit 13 (step S3: second main material measuring process).

[0083] That is, in the raw material weighing process, in order to weigh one batch of main material and minor material, the supply operation of the main supply unit 31 is performed intermittently in two separate steps, thereby weighing a fixed amount of the main material in two separate steps (steps S1, S3), and between the two supply operations of the main supply unit 31, the supply operation of the external supply unit 81 is performed, thereby weighing a fixed amount of the minor material (step S2).

[0084] <First main material weighing process> FIG. 7 is a flowchart showing the flow of the first main material weighing process.

[0085] In the first main material weighing process, the CPU 92 of the control unit 91 starts driving the screw feeder of the main body supply unit 31, thereby starting the supply operation of the main body supply unit 31, i.e., starts the supply of main material from the main body supply unit 31 into the weighing container 21 of the weighing unit 13 (step S11).

[0086] Then, the CPU 92 refers to the electrical signal input from the load cell 22 of the weighing unit 13 to the control unit 91 to determine the main material supply amount, which is the mass of the main material supplied into the weighing container 21, and determines whether the main material supply amount has reached a first set amount (step S12).

[0087] The supply of the main material from the main body supply unit 31 to the weighing container 21 continues until the main material supply amount reaches the first set amount (NO in step S12). When the main material supply amount reaches the first set amount (YES in step S12), the CPU 92 stops driving the screw feeder of the main body supply unit 31, and the supply of the main material from the main body supply unit 31 to the weighing container 21 is stopped (step S13).

[0088] <Small amount material weighing processing> FIG. 8 is a flowchart showing the flow of the small amount material weighing process.

[0089] In the small amount material weighing process, the CPU 92 of the control unit 91 starts supplying compressed air to the ejector 83 of the external supply unit 81, which supplies the small amount of material to be weighed by the weighing unit 13, i.e., the small amount of material to be mixed with the main material, and the supply operation of the external supply unit 81 starts, that is, the supply of the small amount of material from the external supply unit 81 through the input unit 61 into the weighing container 21 of the weighing unit 13 is started (step S21).

[0090] After the external supply unit 81 starts the supply operation, the CPU 92 determines whether or not a preset time has elapsed from the start of the supply operation (step S22).

[0091] When the set time has elapsed from the start of the supply operation of the external supply unit 81 (YES in step S22), the supply of compressed air to the ejector 83 of the external supply unit 81 is stopped, and the supply of the small amount of material from the external supply unit 81 to the measuring container 21 is stopped (step S23). At this time, it is preferable that compressed air is sprayed from the purge port 75 provided in the input pipe 64 of the input unit 61 into the input pipe 64, so that the small amount of material adhering or remaining in the input pipe 64 is dropped into the measuring container 21 without being left behind.

[0092] <Second main material metering process> Figure 9 is a flowchart showing the flow of the second main material metering process.

[0093] In the second main material metering process, the CPU 92 of the control unit 91 starts driving the screw feeder of the main body supply unit 31, and the supply operation of the main body supply unit 31 starts, that is, the supply of the main material from the main body supply unit 31 into the metering container 21 of the metering unit 13 starts (step S31).

[0094] Then, the CPU 92 refers to the electrical signal input from the load cell 22 of the metering unit 13 to the control unit 91, obtains the supply amount of the main material into the metering container 21, and determines whether the supply amount of the main material has reached the second set amount (step S32).

[0095] The supply of the main material from the main body supply unit 31 into the metering container 21 continues until the supply amount of the main material reaches the second set amount (NO in step S32). When the supply amount of the main material reaches the second set amount (YES in step S32), the CPU 92 stops driving the screw feeder of the main body supply unit 31, and the supply of the main material from the main body supply unit 31 into the metering container 21 stops (step S33).

[0096] <Set time correction process> Figure 10 is a flowchart showing the flow of the set time correction process.

[0097] In the minor material metering process, when the set time elapses from the start of the supply operation of the external supply unit 81, the supply operation stops. Therefore, there is a possibility that the supply amount of the minor material into the metering container 21 of the metering unit 13 may be excessive or insufficient with respect to the fixed quantity of the minor material.

[0098] Therefore, the CPU 92 of the control unit 91 performs a set time correction process to correct the set time. In the set time correction process, after the small amount material weighing process is completed and before the second main material weighing process is started, the electrical signal input from the load cell 22 of the weighing unit 13 to the control unit 91 is referenced to obtain the small amount material supply amount (actual measurement value), which is the mass of the small amount material actually supplied into the weighing container 21. Then, the deviation between the small amount material supply amount and the fixed amount is obtained, and it is determined whether the deviation is greater than a threshold value (step S41).

[0099] If the deviation is equal to or smaller than the threshold value (NO in step S41), there is no need to correct the set time, and the set time correction process is terminated.

[0100] If the deviation is greater than the threshold (YES in step S41), the set time is corrected according to the deviation (step S42), and the set time correction process is terminated. If the small amount of material supply is less than the fixed amount, for example, a correction may be made to add a certain time to the current set time, or the set time may be corrected to a longer time as the deviation between the small amount of material supply and the fixed amount increases. If the small amount of material supply is greater than the fixed amount, for example, a correction may be made to subtract a certain time from the current set time, or the set time may be corrected to a shorter time as the deviation between the small amount of material supply and the fixed amount increases.

[0101] If an excess or deficiency of a minor material occurs in one batch operation, in addition to correcting the set time, it is preferable to change the set time in the subsequent batch operation (the next batch operation or subsequent batch operations) so that the excess or deficiency is offset. By doing so, the blending ratio of the main material and the minor material in the raw material stored in the admixture storage section 15 by a predetermined number of batch operations can be made to a predetermined blending ratio.

[0102] <Action and effect> As described above, the main material is supplied to the measuring container 21 of the measuring section 13 by the main supply section 31. The input section 61 is equipped with an input pipe 64, and the input pipe 64 is connected to the external supply section 81, so that the small amount of material supplied by the external supply section 81 is input to the measuring container 21 through the input pipe 64.

[0103] When the small amount of material supplied by the external supply unit 81 is changed, the input unit 61 is cleaned and the original small amount of material is removed from the input unit 61, thereby preventing the original small amount of material from being mixed with the new small amount of material after the change in the input unit 61. Furthermore, since the input unit 61 is configured to input the small amount of material supplied by the external supply unit 81 into the measuring container 21 through the input pipe 64 without allowing it to remain there, the effort required for the cleaning work of removing the original small amount of material from the input unit 61 can be reduced.

[0104] The input section 61 has a side wall 65 tapered downward and a top plate 66 closing the upper end of the side wall 65. The lower end of the side wall 65 opens toward the weighing container 21. The input pipe 64 is connected to the top plate 66, and the inside of the pipe communicates with the space surrounded by the side wall 65. With this configuration, a small amount of material supplied by the external supply section 81 passes through the input pipe 64 and falls from the input pipe 64 into the space surrounded by the side wall 65. Since the side wall 65 has a shape tapering downward, the small amount of material received by the side wall 65 does not remain on the inner surface of the side wall 65, but flows down along the inner surface of the side wall 65 and is input into the weighing container 21 from the opening at the lower end of the side wall 65. Therefore, it is possible to prevent the small amount of material from accumulating on the inner surface of the side wall 65.

[0105] The supply pipe 64 has a straight pipe section 73 extending vertically upward from the top plate 66 perpendicular to the top plate 66, and an inlet pipe section 74 having one end connected to the straight pipe section 73 and the other end opening obliquely downward relative to the vertical direction. This configuration makes it possible to prevent a small amount of material from remaining in the supply pipe 64.

[0106] A purge port 75 is provided at the upper end of the inlet pipe section 74 to introduce air into the pipe for purging small amounts of material from inside the input pipe 64. In this configuration, when cleaning the input section 61, air can be introduced into the input pipe 64 from the purge port 75, and the air can be used to actively purge the small amounts of material from inside the input pipe 64. As a result, even if a small amount of material adheres to the inner surface of the input pipe 64 by electrostatic adhesion, the small amount of material can be effectively purged from inside the input pipe 64, and mixing of the original small amount of material and the new small amount of material after the change can be more effectively prevented in the input section 61.

[0107] In the raw material weighing process, the supply operation of the main supply unit 31 is performed intermittently in a plurality of times in weighing one batch of raw material, and the supply operation of the main supply unit 31 and the external supply unit 81 is controlled so that the supply operation of the external supply unit 81 is performed between the supply operation of the main supply unit 31 and the next supply operation. As a result, in the measuring container 21, the minor material supplied by the external supply unit 81 is sandwiched from above and below by the main material supplied by the main supply unit 31. In this state, the raw materials (main material and minor material) are discharged from the discharge port of the measuring container 21, so that the minor material can be prevented from remaining in the measuring container 21. Then, the raw materials discharged from the measuring container 21 are mixed in the mixer 14, so that the main material and the minor material can be mixed evenly.

[0108] In the small-amount material measuring process, when a set time has elapsed since the start of the supply operation of the external supply unit 81, the supply operation of the external supply unit 81 is stopped.

[0109] A configuration is also conceivable in which the CPU 92 of the control unit 91 refers to an electrical signal input from the load cell 22 of the weighing unit 13 to the control unit 91 to determine the amount of small amount of material to be supplied to the weighing container 21, and when the amount of small amount of material to be supplied reaches a set amount, the supply operation of the external supply unit 81 is stopped. However, if the fixed amount of the small amount of material is small, there is a risk that the small amount of material will be supplied to the weighing container 21 in excess of the fixed amount by supplying the small amount of material to the weighing container 21 after the supply operation of the external supply unit 81 is stopped. By stopping the supply operation of the external supply unit 81 at the point when a set time has elapsed since the start of the supply operation of the external supply unit 81, it is possible to prevent the small amount of material from being excessively supplied to the weighing container 21.

[0110] However, if the supply operation of the external supply unit 81 is controlled over time, it is unclear whether a fixed amount of the small amount of material has actually been supplied to the measuring container 21, and there is a risk of unevenness in the amount of the small amount of material supplied to the measuring container 21.

[0111] Therefore, after the supply operation of the external supply unit 81 is stopped, the electrical signal input from the load cell 22 of the weighing unit 13 to the control unit 91 is referenced to determine the small amount of material supplied (actual value), which is the mass of the small amount of material actually supplied to the weighing container 21. Then, the set time is corrected based on a comparison between the small amount of material supplied and the fixed amount of the small amount of material. This makes it possible to prevent an excess or deficiency in the amount of small amount of material supplied to the weighing container 21. Furthermore, in a configuration in which the set time is corrected, when the fixed amount to be supplied to the weighing container 21 is changed by the supply operation of the external supply unit 81, the set time is automatically changed by correction, so that the user can be saved from the trouble of setting the set time.

[0112] 3 and 4, the input unit 61 is attached to the top plate 67 of the upper housing 11. Therefore, by replacing the top plate of the housing of a measuring and mixing device that does not have the input unit 61 with the top plate 67 to which the input unit 61 is attached, the input unit 61 can be easily installed in the measuring and mixing device.

[0113] <Another example of raw material weighing processing> FIG. 11 is a flowchart showing another example of the ingredient measuring process.

[0114] In the raw material weighing process shown in Figure 6, the supply operation of the main body supply unit 31 is performed intermittently in two separate operations, but if the raw materials for the plastic product supplied to the injection molding machine 2 contain multiple types of small amounts of material, the supply operation of the main body supply unit 31 is performed intermittently in three or more separate operations, and the supply operation of the external supply unit 81 is performed between each supply operation of the main body supply unit 31.

[0115] For example, when the raw materials for a plastic product include two types of first and second minor materials, the raw material weighing process first involves a first supply operation of the main supply unit 31, which supplies a first set amount of main material to the weighing container 21 of the weighing unit 13 (step S101: first main material weighing process).

[0116] Next, the supply operation of the first external supply unit 81 is performed, and a fixed amount of the first small amount of material is supplied to the measuring container 21 of the measuring unit 13 by the supply operation (Step S102: first small amount of material measuring process).

[0117] Thereafter, the main supply unit 31 performs a second supply operation, and the second set amount of main material is supplied to the measuring container 21 of the measuring unit 13 by the second supply operation (step S103: second main material measuring process).

[0118] Next, the second external supply unit 81 performs a supply operation, and the supply operation supplies a fixed amount of the second small amount of material to the measuring container 21 of the measuring unit 13 (Step S104: second small amount material measuring process).

[0119] Thereafter, the main supply unit 31 performs a third supply operation, and the third set amount of main material remaining after subtracting the sum of the first set amount and the second set amount from the fixed amount of main material is supplied to the measuring container 21 of the measuring unit 13 (step S105: third main material measuring process).

[0120] As a result, the first small amount of material and the second small amount of material are sandwiched between the main material from above and below inside the measuring container 21. In this state, the raw materials (main material, first small amount of material, and second small amount of material) are discharged from the discharge port of the measuring container 21, thereby preventing the first small amount of material and the second small amount of material from remaining inside the measuring container 21. Then, the raw materials discharged from the measuring container 1521 are mixed in the mixer 14, thereby enabling the main material, the first small amount of material, and the second small amount of material to be mixed evenly.

[0121] FIG. 12 is a flowchart showing still another example of the raw material measuring process.

[0122] In the raw material weighing process shown in Fig. 6, in order to weigh one batch of main material and minor material, the supply operation of the main supply unit 31 is performed intermittently in two separate operations, thereby weighing a fixed amount of the main material in two separate operations, and the supply operation of the external supply unit 81 is performed between the two supply operations of the main supply unit 31, thereby weighing a fixed amount of the minor material. When the raw materials of a plastic product include, for example, a main material, a crushed material, and one type of minor material, the raw material weighing process shown in Fig. 12 may be performed. The crushed material is supplied to the weighing container 21 by the supply operation of the main supply unit 31B.

[0123] In the raw material weighing process shown in FIG. 12, first, a first supply operation of the main supply unit 31A is performed, and a first set amount of main material is supplied to the measuring container 21 of the measuring unit 13 by this supply operation (step S111: first main material weighing process).

[0124] Next, the main body supply unit 31B performs a supply operation, and by this supply operation, a fixed amount of the pulverized material is supplied to the measuring container 21 of the measuring unit 13 (step S112: pulverized material measuring process).

[0125] Thereafter, the external supply unit 81 performs a supply operation, and a fixed amount of the small amount of material is supplied to the measuring container 21 of the measuring unit 13 by the supply operation (step S113: small amount material measuring process).

[0126] Then, the second supply operation of the main material supply unit 31A is performed, and by this supply operation, the remaining second set amount of the main material obtained by subtracting the first set amount from the fixed amount of the main material is supplied to the measuring container 21 of the measuring unit 13 (step S114: second main material measuring process).

[0127] That is, in the example of the raw material measuring process shown in FIG. 12, for measuring the main material, the pulverized material, and the small amount material for one batch, the supply operation of the main body supply unit 31A is intermittently performed in two steps. As a result, the measurement of the fixed amount of the main material is performed in two steps (steps S111, S114). Between the two supply operations of the main body supply unit 31A, the supply operation of the main body supply unit 31B and the supply operation of the external supply unit 81 are sequentially performed, so that the measurement of the fixed amount of the pulverized material and the measurement of the fixed amount of the small amount material are performed (steps S112, S113).

[0128] <Operational Effect> A mixed material obtained by mixing the main material (plastic pellets), the pulverized material, and the small amount material (master batch) at a predetermined mixing ratio can be obtained, and the mixed material can be transported and supplied to the injection molding machine 2.

[0129] <Other Embodiments> FIG. 13 is a diagram schematically showing the configuration of a metering and mixing device 111 according to another embodiment of the present invention. In FIG. 13, parts corresponding to the respective parts shown in FIG. 1 are given the same reference numerals as those parts. Hereinafter, the configuration of the metering and mixing device 111 shown in FIG. 13 will be described by taking up the differences from the configuration of the metering and mixing device 1 shown in FIG. 1.

[0130] In the metering and mixing device 111, one input pipe 64 is provided in the input unit 61. One end of the raw material supply pipe 82 of a plurality of external supply units 81 is selectively switched and connected to the input pipe 64.

[0131] When the small amount of material contained in the raw material of the plastic product supplied to the injection molding machine 2 is changed, the external supply unit 81 that supplies the original small amount of material is disconnected from the input pipe 64, and the external supply unit 81 that supplies a new small amount of material is connected to the input pipe 64. As a result, the new small amount of material supplied by the external supply unit 81 is input into the measuring container 21 of the measuring unit 13 through the input pipe 64. Therefore, by switching the external supply unit connected to the input pipe 64, the small amount of material supplied to the measuring container 21, i.e., the small amount of material to be measured by the measuring unit 13, can be changed.

[0132] Before the external supply unit 81 for supplying a new small amount of material is connected to the input pipe 64, the input unit 61 is cleaned to remove the original small amount of material from the input pipe 61. At this time, it is preferable to actively purge the original small amount of material from the input pipe 64 by introducing air into the input pipe 64 from the purge port 75. This makes it possible to more effectively prevent the original small amount of material from being mixed with the new small amount of material after the change in the input unit 61.

[0133] <Modification> Although the embodiment of the present invention has been described above, the present invention can be embodied in other forms.

[0134] 3 and 4, for example, a configuration has been taken up in which one input hopper 62 is provided in the input section 61, and four input pipes 64 are connected to the top plate 66 of the input hopper 62. However, the present invention is not limited to this configuration, and a configuration may be adopted in which a plurality of input hoppers 62 are provided, and a plurality of input pipes 64 are connected to the top plate of each input hopper 62, as shown in FIG.

[0135] The shape of the input hopper 62 is not limited to the above-mentioned shape, and other shapes may be adopted.

[0136] Also, the input hopper 62 may be omitted. In that case, a connection port of a size corresponding to the straight pipe portion 73 may be formed in the top plate 67 of the upper housing 11, and the straight pipe portion 73 of the input pipe 64 may be inserted into the connection port, or the straight pipe portion 73 may be aligned so that the opening of the lower end of the straight pipe portion 73 overlaps with the connection port, and the straight pipe portion 73 may be connected to the connection port. Then, an introduction pipe may be connected to the connection port or the lower end of the straight pipe portion 73 inserted into the connection port, and the introduction pipe may extend downward toward the measuring container 21 of the measuring unit 13, so that a small amount of material may be introduced from the input pipe 64 into the measuring container 21 through the introduction pipe. In this configuration, in order to prevent the air for transportation flowing through the input pipe 64 from hitting the measuring container 21 and adversely affecting the measurement in the measuring unit 13, it is preferable to provide a configuration for removing air in the middle of the straight pipe portion 73.

[0137] In the configuration shown in Fig. 3, the inlet pipe section 74 of the input pipe 64 is curved convexly upward and connected to the upper end of the straight pipe section 73 from above. However, the present invention is not limited to this, and it is sufficient that the inlet pipe section 74 is provided so that the center line of the inlet pipe section 74 intersects at an acute angle with the center line of the straight pipe section 73 extending in the vertical direction (up-down direction). For example, the upper end of the straight pipe section 73 and one end of the inlet pipe section 74 may be cut obliquely, and one end of the inlet pipe section 74 may be directly connected to the upper end of the straight pipe section 73, so that the inlet pipe section 74 is connected to the straight pipe section 73 from obliquely below at an acute angle. Alternatively, a configuration may be adopted in which the upper end of the straight pipe section 73 and one end of the inlet pipe section 74 are connected to a connecting block.

[0138] 8, when a set time has elapsed since the start of the supply operation of the external supply unit 81, the supply of compressed air to the ejector 83 of the external supply unit 81 is stopped, and the supply of the small amount of material from the external supply unit 81 to the measuring container 21 is stopped. However, the supply stop amount may be set in consideration of the fixed amount of the small amount of material and the amount of the small amount of material supplied to the measuring unit 13 during the time difference from the stop of the supply of compressed air to the ejector 83 to the completion of the measurement of the small amount of material, the supply amount of the small amount of material to the measuring unit 13 during the supply operation of the external supply unit 81 (measurement value by the measuring unit 13) is measured in real time, and when the supply stop amount is measured by the measuring unit 13, the supply of compressed air to the ejector 83 of the external supply unit 81 is stopped, and the supply of the small amount of material from the external supply unit 81 to the measuring container 21 may be stopped.

[0139] In addition, in the raw material weighing process shown in Figure 6, a small amount of material weighing process is performed between the first main material weighing process and the second main material weighing process, but the first main material weighing process and the second main material weighing process may be performed after the small amount of material weighing process is performed, or the small amount of material weighing process may be performed after the first main material weighing process and the second main material weighing process.

[0140] Instead of the raw material weighing process shown in FIG. 12, the first main material weighing process and the small amount of material weighing process may be performed after the crushed material weighing process, and then the second main material weighing process may be performed. Also, the first main material weighing process and the crushed material weighing process may be performed after the small amount of material weighing process, and then the second main material weighing process may be performed. The first main material weighing process and the second main material weighing process may be performed after the crushed material weighing process and the small amount of material weighing process. The order in which the crushed material weighing process and the small amount of material weighing process are performed may be appropriately changed.

[0141] The metering and mixing device 1, 111 may not be provided with the mixing section 14. In this case, the mixed material that has not been mixed by stirring may not be sufficiently mixed with each powdered material when it is supplied to the mixed material storage section 15. However, the mixed material is then pneumatically transported from the mixed material storage section 15 to the destination hopper 41, so that each powdered material is mixed to some extent. In addition, a mixing mechanism may be provided between the secondary transport pipe 45 and the destination hopper 41, or between the destination hopper 41 and the injection molding machine 2, and the mixed material may be mixed by the mixing mechanism before being fed into the injection molding machine 2.

[0142] In addition, although the other end of the raw material introduction pipe 85 of the external supply unit 81 is connected to the raw material tank 84, the other end of the raw material introduction pipe 85 may be introduced into a raw material storage bag that stores the raw material and placed in a small amount of material stored in the raw material storage bag.

[0143] In this case, for example, if an identification number assigned to the raw material storage bag is input into the control unit 91, and the CPU 92 of the control unit 91 determines that the raw material storage bag identified from that identification number is different from the raw material storage bag that stores small amounts of material contained in the raw material of the plastic product supplied to the injection molding machine 2, the supply operation by the external supply unit 81 may be prohibited.

[0144] The identification number of the raw material storage bag may be input into the control unit 91 by the user manually operating an operation panel (not shown), or a barcode representing the identification number may be attached to the raw material storage bag and the barcode may be read by a scanner connected to the control unit 91, thereby inputting the identification number into the control unit 91.

[0145] In addition, an identification number of a raw material storage bag that stores small amounts of material contained in the raw material of the plastic product supplied to the injection molding machine 2 is registered in the memory 93 of the control unit 91, and if there is a discrepancy between the registered identification number and the identification number input to the control unit 91, it may be determined that the raw material storage bag identified from the identification number input to the control unit 91 is different from the raw material storage bag that stores small amounts of material contained in the raw material of the plastic product supplied to the injection molding machine 2.

[0146] The user may manually operate an operation panel (not shown) to register the identification number in memory 93. Alternatively, control unit 91 may be communicably connected to a control unit of injection molding machine 2, and control unit 91 may receive, from the control unit of injection molding machine 2, an identification number of a raw material storage bag that stores a small amount of material contained in the raw material of the plastic product, and the received identification number may be registered in memory 93.

[0147] In the control unit of the injection molding machine 2, whether the mixed materials mixed in one batch operation in the metering and mixing device 1, 111 were used in the Nth to N+ath (N: natural number, a: 0 or natural number) shots of injection molding is recorded in memory. In a configuration in which the control unit 91 is communicably connected to the control unit of the injection molding machine 2, the mixing ratio of the mixed materials mixed in one batch operation is recorded in the memory 93 of the control unit 91, so that when a defect occurs in an injection molding shot of the injection molding machine 2, the control unit 91 can check the mixing ratio of the mixed materials used in the shot where the defect occurred.

[0148] In addition, the external supply section 81 is configured to supply a small amount of material from the raw material tank 84 to the input section 61 by the action of the ejector 83, but is not limited to this, and may be configured to supply a small amount of material to the input section 61 by a screw feeder or a known vibrating feeder (electromagnetic feeder).

[0149] Although a masterbatch has been mentioned as an example of a minor ingredient, the minor ingredient may be an additive other than the masterbatch, such as a foaming agent.

[0150] The destination of the transport is not limited to the injection molding machine 2, but may be other types of molding machines, or may be a device other than a molding machine, such as a dryer that dries powdered or granular material.

[0151] In addition, various design modifications can be made to the above-described configuration within the scope of the claims. [Explanation of symbols]

[0152] 1,111:Measuring and mixing device 13:Measuring part 14: Mixing section 21:Measuring container 31 (31A, 31B, 31C): Main body supply section (1st supply section) 61: Insertion section 64: Input pipe 65: Side wall 66: Tabletop 73: Straight pipe section 74:Inlet pipe section 75: Purge port 81: External supply section (second supply section) 83: Ejector 91: Control unit

Claims

1. A measuring unit that measures the raw material contained in the measuring container; A first supply unit that supplies the raw material to the measuring container; A second supply unit that supplies a different type of raw material from the raw material to be supplied by the first supply unit toward the measuring unit; a feed unit including a feed pipe to which the second supply unit is connected, the feed unit feeding the raw material supplied by the second supply unit through the feed pipe into the measuring container without allowing the raw material to stagnate; a control unit that controls each supply operation of the first supply unit and the second supply unit so that a fixed amount of each of a plurality of types of raw materials is measured by the measuring unit.

2. 2. The metering and mixing device according to claim 1, wherein the feeding pipe has a straight pipe section extending vertically upward and an inlet pipe section having one end connected to the straight pipe section and the other end opening obliquely downward with respect to the vertical direction.

3. 4. The measuring and mixing apparatus according to claim 3, wherein the inlet pipe section is provided with a purge port for introducing air into the pipe for purging the raw material from the input pipe.

4. The inlet pipe portion is curved upwardly convexly from the straight pipe portion, 5. The metering and mixing device according to claim 4, wherein the purge port is provided at an upper end of the convexly curved inlet pipe portion.

5. The input section includes a side wall tapering downward and a top plate closing an upper end of the side wall, The lower end of the side wall is open toward the measuring container, The measuring and mixing device according to claim 1 , wherein the input pipe is connected to the top plate and the inside of the pipe communicates with a space surrounded by the side wall.

6. 2. The measuring and mixing device according to claim 1, wherein the control unit controls each of the supply operations of the first supply unit and the second supply unit so that, in measuring one batch of multiple types of raw materials, the supply operation of the first supply unit is performed intermittently in multiple steps, and the supply operation of the second supply unit is performed between the supply operation of the first supply unit and the next supply operation of the first supply unit.

7. The measuring and mixing device according to claim 6, wherein the control unit controls the supply operation of the first supply unit while referring to the measurement value by the measuring unit, and stops the supply operation of the first supply unit when the amount of raw material supplied by the first supply unit to the measuring container reaches a set amount.

8. The measuring and mixing device according to claim 6 , wherein the control unit stops the supplying operation of the second supply unit when a set time has elapsed since the start of the supplying operation of the second supply unit.

9. The measuring and mixing device according to claim 8, wherein the control unit, after the supply operation of the second supply unit is stopped, calculates the amount of raw material supplied to the measuring container by the supply operation of the second supply unit from the measurement value by the measuring unit, and corrects the set time based on a comparison between the calculated amount and a fixed amount to be supplied to the measuring container by the supply operation of the second supply unit.

10. 7. The measuring and mixing device according to claim 6, further comprising a mixing section for mixing the plurality of types of raw materials each measured in a fixed amount by the measuring section.

11. The second supply unit is provided in plurality, The input section includes a plurality of the input pipes, The measuring and mixing device according to any one of claims 1 to 10, wherein the second supply section is connected to the input pipe in a one-to-one manner.

12. The second supply unit is provided in plurality, The input section includes a single input pipe, The measuring and mixing device according to any one of claims 1 to 10, wherein the second supply unit is selectively connected to the input pipe.

13. The raw material to be supplied by the first supply unit is a main material that is supplied to the measuring container in a relatively large amount, 11. The measuring and mixing device according to claim 1, wherein the raw material to be supplied by the second supply unit is a small amount of material that is supplied to the measuring container in a relatively small amount.

14. 13. The metering and mixing device according to claim 12, wherein the second supply section includes an ejector for pneumatically transporting the raw material.

Images