Raw material supplying device

Abstract

To provide a raw material supplying device which allows a user to freely select a mixed material when mixing two or more kinds of raw materials, prevents an auxiliary raw material from being undesirably supplied when the supply of the auxiliary raw material is stopped due to raw material change or the like, and can respond to a quick raw material change.SOLUTION: In a raw material supplying device in which a main raw material passage (12) and an auxiliary raw material passage (14) are set at a downward gradient so that each raw material can flow down under its own weight, and a baffle plate (16) is disposed near a downstream end opening (12a) of the main raw material passage (12) and suspended downward from an upper portion of the downstream end opening (12a), a main raw material passing space (S) is formed at least between a side surface of the baffle plate (16) and the downstream end opening (12a), a screw conveyor (18) for feeding auxiliary raw materials which continuously discharges minute amounts of the auxiliary raw materials (N) is provided on the upstream side of the auxiliary raw material passage (14), and a shutter device (20) for opening and closing an auxiliary raw material outlet is attached to a tip side of a cylindrical body of the screw conveyor (18) for feeding the auxiliary raw materials.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a raw material supply device used for raw material supply and mixed raw material supply in an extrusion molding machine, an inflation molding machine, and the like.

Background Art

[0002] In a molding process using an extrusion device such as an extrusion molding machine or an inflation molding machine, in addition to the case of performing molding with only one type of raw material (main raw material), two or more types of raw materials (main raw material, auxiliary raw materials [for coloring and material improvement]) may be mixed and used.

[0003] As a conventional extrusion device corresponding to this, for example, as shown in the following Patent Document 1 (Japanese Patent No. 3821795), in addition to a main raw material hopper, a main raw material metering hopper, and a main raw material passage having a predetermined downward gradient, a substantially vertical auxiliary raw material hopper, an auxiliary raw material metering hopper, an auxiliary raw material cutting screw conveyor, and an auxiliary raw material passage are provided. The lower end side of this auxiliary raw material passage is connected to the lower end side of the main raw material passage in a bifurcated manner. A certain amount of the main raw material flowing down by its own weight in the main raw material passage and a certain amount of the auxiliary raw material cut out by the auxiliary raw material cutting screw conveyor and falling in pieces and flowing down by its own weight in the auxiliary raw material passage are made to merge at the confluence connection part, and then are supplied into the heating cylinder of the extrusion molding machine from the raw material supply port of the extrusion molding machine through the raw material introduction path.

[0004] In this device, an inverted trapezoidal "baffle plate" is provided. When the main raw material flows down from the narrowed lower end of the inverted trapezoidal "baffle plate" to the confluence connection part, at the same time, it wraps around the inclined side of the "baffle plate" and is guided from the auxiliary raw material passage to the "baffle plate" and flows down in the direction of its narrowed lower end so as to cover the auxiliary raw material flowing down above it, thereby entraining the auxiliary raw material into the main raw material, and the mixing of the main raw material and the auxiliary raw material is achieved.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, when using two or more raw materials such as the main raw material and the auxiliary raw material in the above conventional device, there may be a case where it is desired to stop the extraction of the auxiliary raw material during raw material replacement or the like during operation. However, in the above conventional device, since the extraction part (auxiliary raw material outlet) of the screw conveyor for extracting the auxiliary raw material provided on the upstream side of the auxiliary raw material passage is exposed, there may occur a problem that the auxiliary raw material in the screw conveyor for extracting the auxiliary raw material spills out at an unintended timing and has an adverse effect on the product. For this reason, in order to completely stop the supply of the auxiliary raw material, there is a problem that all of the auxiliary raw material must be removed while paying attention not to spill the auxiliary raw material in the screw conveyor for extracting the auxiliary raw material.

[0007] Therefore, the main object of the present invention is to provide a raw material supply device that can freely select a mixing material when two or more raw materials are to be mixed, and when stopping the supply of the auxiliary raw material due to raw material replacement or the like, the auxiliary raw material is not supplied undesirably and can cope with quick raw material replacement.

Means for Solving the Problems

[0008] To achieve the above object, the present invention configures a raw material supply device 10 as follows, for example, as shown in FIGS. 1 to 3. That is, the downstream end side of the main raw material passage 12 for feeding a certain amount of the main raw material M downward and the downstream end side of the auxiliary raw material passage 14 for feeding a certain amount of the auxiliary raw material N downward are connected in a bifurcated manner and communicated. At this confluence connection part P, the main raw material M and the auxiliary raw material N are made to merge and flow downward by their own weight, which is the raw material supply device 10. The main raw material passage 12 and the auxiliary raw material passage 14 are set to have a downward gradient that allows each raw material to flow down by its own weight. And it is located near the downstream end opening 12a in the main raw material passage 12, and a baffle plate 16 is vertically provided downward from the upper part of the downstream end opening 12a. At least a main raw material passage space S is formed between the side surface of the baffle plate 16 and the downstream end opening 12a. On the upstream side of the auxiliary raw material passage 14, there are provided a cylinder 18a constituting the auxiliary raw material conveyance path, a conveyance screw 18b rotatably disposed inside the cylinder 18a, and a motor 18c for rotating the conveyance screw 18b. An auxiliary raw material cutting screw conveyor 18 is provided for continuously discharging the auxiliary raw material N while metering it in a small amount from an auxiliary raw material outlet 18d opened on the lower surface of the tip of the cylinder 18a. A shutter device 20 for opening and closing the auxiliary raw material outlet 18d is attached to the tip side of the cylinder 18a in the auxiliary raw material cutting screw conveyor 18.

[0009] In this invention, while a certain amount of the main raw material M flows down by its own weight along the downward gradient of the main raw material passage 12 and heads towards the confluence connection part P, at the same time, a certain amount of the auxiliary raw material N also flows down by its own weight along the auxiliary raw material passage 14 along the downward gradient and heads towards the confluence connection part P. When the main raw material M exits the main raw material passage 12, it is restricted by the baffle plate 16, and the central part of the flow of the main raw material M is concave in the shape of the baffle plate 16 at the back of the baffle plate 16. This part is the empty area Q through which the main raw material M does not pass. On the other hand, for the auxiliary raw material N, there is the empty area Q on the back side of the baffle plate 16 on the auxiliary raw material side where the main raw material M on the downstream side of the baffle plate 16 that has passed through the baffle plate 16 does not enter. Therefore, the auxiliary raw material N introduced into this empty area Q is hardly affected by the downward momentum of the main raw material M and flows down while being wrapped by the main raw material M. As a result, the auxiliary raw material N smoothly flows down by its own weight even without a feeding screw conveyor and merges well with the main raw material M and flows downward.

[0010] Furthermore, in the raw material supply device 10 of the present invention, since the shutter device 20 for opening and closing the auxiliary raw material outlet 18d is attached to the tip side of the cylinder body 18a of the auxiliary raw material extraction screw conveyor 18 provided on the upstream side of the auxiliary raw material passage 14, when stopping the supply of the auxiliary raw material N due to a raw material change or the like, if the auxiliary raw material outlet 18d is closed by the shutter device 20, the so-called "avalanche phenomenon" in which the auxiliary raw material N is undesirably supplied will not occur.

[0011] In the present invention, it is preferable that the auxiliary raw material passage 14 is set to a steeper downward gradient than the main raw material passage 12. In this case, the auxiliary raw material N will flow down vigorously and jump into the region Q where the main raw material M does not pass, and will be well wrapped by the main raw material M.

[0012] Also, in the present invention, it is preferable that the cross-sectional shape of the outlet of the main raw material passage 12 is circular, and the baffle plate 16 is disposed so as to be displaceable so as to cross the outlet of the main raw material passage 12 from the vertical direction, and its lower part is preferably formed to be narrower as it goes downward. In this case, the upper surface of the main raw material M immediately after passing through the baffle plate 16 is substantially U-shaped or V-shaped with a concave central portion, and since the region Q where the main raw material M does not pass is largely opened upward, the auxiliary raw material N can be easily introduced into the region Q.

[0013] Furthermore, in the present invention, the shutter device 20 is a short tubular cylindrical sleeve 22 that slidably surrounds the outer periphery of the cylinder body 18a, and a rail strip 22a made of a ferromagnetic material is axially extended on its surface. The cylindrical sleeve 22, a transmission shaft 24 provided with a contact portion 24a that contacts the rail strip 22a at the tip, and a magnet 24b is attached to the surface of the contact portion 24a. It is preferably composed of a transmission shaft 24 and an opening and closing motor 26 that rotates the transmission shaft 24 forward and backward. In this case, a shutter device 20 with a simple structure, few failures, and excellent maintainability can be constructed in a limited narrow space.

Advantages of the Invention

[0014] According to the present invention, when it is desired to mix two or more raw materials, a mixing material can be freely selected, and when the supply of a secondary raw material is stopped due to a change in the raw material or the like, the secondary raw material is not undesirably supplied, and a raw material supply device capable of corresponding to a quick change in the raw material can be provided.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0016] Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an extrusion device A to which a raw material supply device 10 according to an embodiment of the present invention is applied, and FIG. 2 is a side sectional view of a main part of the raw material supply device 10 in FIG. 1.

[0017] In FIG. 1, this extrusion device A is roughly composed of an extrusion device main body 1 and a raw material supply device 10, and the raw material supply device 10 includes a main raw material supply part 10A, a secondary raw material supply part 10B, and a raw material introduction path 10C communicating with the raw material supply port 2 of the extrusion device main body 1. In the embodiment of FIG. 1, a case where one secondary raw material supply part 10B is provided for one main raw material supply part 10A, that is, one type of secondary raw material N is supplied to the main raw material M is shown. However, in view of the production efficiency and economy of the molded product, it is more preferable to provide a plurality of secondary raw material supply parts 10B in parallel with one main raw material supply part 10A.

[0018] The extrusion apparatus main body 1 is composed of, for example, a heating cylinder 1a to which a main raw material M and a sub-raw material N are supplied, a feed screw 1b disposed in the heating cylinder 1a, and a motor 1c that drives the feed screw 1b, etc.

[0019] The main raw material supply unit 10A includes a main raw material hopper 30, a main raw material weighing hopper 32, and a main raw material passage 12. Further, the sub-raw material supply unit 10B includes a sub-raw material hopper 40, a sub-raw material weighing hopper 42, a sub-raw material passage 14, and a sub-raw material cutting screw conveyor 18.

[0020] The main raw material hopper 30 accommodates the main raw material M that is the main body of the molding material, and is provided with a shutter member 30a that can open and close the downstream end opening. Further, the main raw material weighing hopper 32 has a main raw material load cell 32a that weighs the main raw material M in the main raw material weighing hopper 32 and measures a fixed amount of the main raw material M supplied from the main raw material hopper 30 when the main raw material M in the main raw material weighing hopper 32 reaches a predetermined lower limit value.

[0021] The sub-raw material hopper 40 accommodates the sub-raw material N of the molding material, and is provided with a shutter member 40a that can open and close the downstream end opening. Further, the sub-raw material weighing hopper 42 has a sub-raw material load cell 42a that weighs the sub-raw material N in the sub-raw material weighing hopper 42 and measures a fixed amount of the sub-raw material N supplied from the sub-raw material hopper 40 when the sub-raw material N in the sub-raw material weighing hopper 42 reaches a predetermined lower limit value.

[0022] The main raw material passage 12 is composed of, for example, a metal cylindrical pipe, is disposed between the main raw material weighing hopper 32 and the raw material introduction path 10C, and is disposed with a downward gradient (angle θ1) such that a fixed amount of the main raw material M weighed by the main raw material load cell 32a flows down by its own weight (see FIG. 2).

[0023] The auxiliary raw material passage 14 is also composed of, for example, a cylindrical pipe made of metal. It is disposed between the auxiliary raw material weighing hopper 42 and the raw material introduction passage 10C, and is set to a downward gradient (angle θ2) such that a fixed amount of auxiliary raw material N weighed by the auxiliary raw material load cell 42a falls by its own weight (see Fig. 2). The downward gradients of both may be the same, or the downward gradient angle of the auxiliary raw material passage 14 may be set to a steeper downward gradient than that of the main raw material passage 12. In this example, the auxiliary raw material passage 14 is set to a posture with an inclination (angle θ2) close to being vertical (angle θ1 ≪ angle θ2) to facilitate the gravity flow of the auxiliary raw material N. Of course, it is not limited to this, and the downward gradient of this auxiliary raw material passage 14 may be steeper than that of the main raw material passage 12. Also, as described above, when a plurality of auxiliary raw material supply units 10B are provided in parallel with one main raw material supply unit 10A, the auxiliary raw material passages 14 of each auxiliary raw material supply unit 10B are preferably gathered upstream of the empty region Q (see Fig. 2) where the main raw material M on the back of the baffle plate 16 does not flow in.

[0024] The downstream end side of the main raw material passage 12 and the downstream end side of the auxiliary raw material passage 14 are communicatively connected so as to form a bifurcated confluence connection portion P, and this confluence connection portion P is communicated with the raw material introduction passage 10C. Note that an auxiliary raw material cutting screw conveyor 18 is disposed on the upper end side of the above-mentioned auxiliary raw material passage 14.

[0025] As shown in Fig. 3, the auxiliary raw material cutting screw conveyor 18 includes a cylindrical body 18a with a closed tip portion, a conveying screw 18b rotatably disposed inside the cylindrical body 18a, and a motor 18c for rotating the conveying screw 18b. It is for continuously discharging the auxiliary raw material N while finely weighing it from an auxiliary raw material outlet 18d opened on the lower surface of the tip of the cylindrical body 18a. An auxiliary raw material inlet 18e is formed on the upper surface of the rear end portion of the cylindrical body 18a of this auxiliary raw material cutting screw conveyor 18, and a hopper 18f is attached to this auxiliary raw material inlet 18e. Therefore, in combination with the above-mentioned auxiliary raw material outlet 18d, the inside of the cylindrical body 18a is configured as an auxiliary raw material conveying path. Also, a shutter device 20 for opening and closing the auxiliary raw material outlet 18d is attached to the tip side of the cylindrical body 18a of this auxiliary raw material cutting screw conveyor 18.

[0026] As shown in FIG. 3, the shutter device 20 includes a short tubular cylindrical sleeve 22 that slidably surrounds the outer periphery of the above-described cylindrical body 18a. A rail strip 22a made of a ferromagnetic material is axially extended on the surface of the cylindrical sleeve 22. The shutter device 20 further includes a transmission shaft 24 attached to the cylindrical sleeve 22 and provided with a contact portion 24a that contacts the rail strip 22a at its tip. A magnet 24b is attached to the surface of the contact portion 24a of the transmission shaft 24. The shutter device 20 is composed of the transmission shaft 24 and an opening / closing motor 26 that rotates the transmission shaft 24 forward and backward. A flange portion 22b with an enlarged outer diameter is provided at the base end portion of the cylindrical sleeve 22 as needed. The flange portion 22b abuts against the contact portion 24a of the transmission shaft 24 to be locked, so that the cylindrical sleeve 22 does not fall off from the tip of the cylindrical body 18a (see FIG. 4).

[0027] The above-described cylindrical sleeve 22 is formed of a hard material such as metal or resin. In particular, it is preferably formed of a material that does not cause so-called contamination in the auxiliary raw material passage 14. As the ferromagnetic material constituting the rail strip 22a attached to the cylindrical sleeve 22, it is particularly preferable to use a ferrite stainless steel such as SUS430 or a martensitic stainless steel such as SUS403 from the viewpoints of easy availability of materials and mechanical properties. However, when the cylindrical sleeve 22 is made of a ferromagnetic material such as SUS430, the side surface of the cylindrical sleeve 22 itself functions as the rail strip 22a.

[0028] The contact portion 24a of the above-described transmission shaft 24 is provided with an enlarged outer diameter at the tip portion of the transmission shaft 24. As the magnet 24b attached to the contact portion 24a, a ferrite magnet, an alloy magnet, an electromagnet, etc. can be used, and its shape can also be a ring-shaped object, a sheet-shaped object, etc.

[0029] Near the downstream end opening 12a in the main raw material passage 12, as shown in FIG. 2, a contact plate 34 with a circular hole serving as the outlet 34a of the main raw material passage 12 is arranged. Opposite to the outlet 34a, on the downstream side surface of the contact plate 34, a baffle plate 16 for deforming the upper surface shape of the main raw material M when passing through the main raw material passage 12 into a substantially V shape is disposed.

[0030] The baffle plate 16 is composed of, for example, a plate body protruding downward from the upper end of the outlet 34a of the main raw material passage 12 as shown in FIG. 2. (Although not shown in FIG. 2), both corners in the width direction of its lower part 16a are notched so that the lower part 16a becomes narrower as it goes downward. The position of this baffle plate 16 in the vertical direction can be adjusted so that the protruding amount with respect to the outlet 34a can be adjusted. For example, it is respectively provided on both sides in the width direction of the contact plate 34 and is supported so as to be vertically movable by a pair of left and right guide members 36 provided with guide grooves and a holding member such as a bolt screwed in accordance with the guide grooves.

[0031] Next, the operation of the extrusion device A equipped with the raw material supply device 10 having the above configuration will be described. First, after setting the baffle plate 16 in the main raw material passage 12 at a predetermined position shown in FIG. 2, the shutter member 30a of the main raw material hopper 30 and the shutter member 40a of the auxiliary raw material hopper 40 are respectively opened. Thereby, the main raw material M stored in the main raw material hopper 30 is supplied to the main raw material weighing hopper 32, a certain amount is weighed by the main raw material load cell 32a, and this certain amount of the main raw material M is accurately input into the main raw material passage 12 at a predetermined supply amount. On the other hand, the auxiliary raw material N stored in the auxiliary raw material hopper 40 is supplied to the auxiliary raw material weighing hopper 42, a certain amount is weighed by the auxiliary raw material load cell 42a, and this certain amount of the auxiliary raw material N is accurately input into the auxiliary raw material passage (23) at a predetermined supply amount through the auxiliary raw material cutting screw conveyor 18. At this time, the cylindrical sleeve 22 of the shutter device 20 in the auxiliary raw material cutting screw conveyor 18 has retreated to a position where the auxiliary raw material outlet 18d is opened as shown in FIG. 3.

[0032] A certain amount of the main raw material M introduced into the main raw material passage 12 flows down by its own weight along the downward gradient of the main raw material passage 12. When it exits the outlet 34a of the main raw material passage 12, it passes through the main raw material passage space S, which is the gap between the lower part 16a of the baffle plate 16 and the inner peripheral surface of the outlet 34a, due to the baffle plate 16 near the downstream end opening 12a. Therefore, immediately after passing through the baffle plate 16, the upper surface shape of the main raw material M becomes concave in a substantially U or V shape by the lower part 16a of the baffle plate 16 and flows down. [When the lower part 16a of the baffle plate 16 is U-shaped or rectangular, it becomes a U shape with a non-spreading upper surface. When the lower part 16a of the baffle plate 16 is V-shaped or the two corners are cut off, the upper surface shape becomes an open V shape.] And as shown in FIG. 2, a free space Q [= the part where the upper surface shape is concave] where the main raw material M does not flow in is generated on the back of the baffle plate 16.

[0033] On the other hand, the auxiliary raw material N introduced into the auxiliary raw material passage 14 flows down a steep downward gradient and is introduced into the free space Q. As described above, the upper surface shape of the main raw material M is concave in a substantially U or V shape. Therefore, while the two side portions thereof move to wrap the auxiliary raw material N, the auxiliary raw material N is evenly drawn into the flow of the main raw material M at the confluence connection portion P. The blending of the main raw material M and the auxiliary raw material N is accurately performed, and the entire amount smoothly drops through the raw material introduction path 10C and is supplied to the extrusion device main body 1.

[0034] When the auxiliary raw material passage 14 is set to a steeper downward gradient than the main raw material passage 12, it will fall by its own weight faster than the main raw material M and head towards the confluence connection portion P. However, the main raw material M is not pushed by the flowing momentum of the auxiliary raw material N introduced into this free space Q. As described above, the auxiliary raw material N is evenly wrapped by the main raw material M, and the entire amount smoothly drops through the raw material introduction path 10C and is supplied to the extrusion device main body 1 so as to be drawn into the flow of the main raw material M at the confluence connection portion P.

[0035] The main raw material M and the auxiliary raw material N supplied to the extrusion apparatus main body 1 are melted and kneaded while moving in the heating cylinder 1a by the feed screw 1b, and then formed into a predetermined shape by a die or a nozzle (not shown). Then, when the taking of the planned quantity of products is completed, a raw material change for manufacturing the next molded product is carried out. At this time, the opening / closing motor 26 of the shutter device 20 is rotationally operated in a predetermined direction, and as shown in FIG. 4, the cylindrical sleeve 22 is advanced to close the auxiliary raw material outlet 18d. By doing so, the supply of the auxiliary raw material N from the auxiliary raw material cutting screw conveyor 18 to the auxiliary raw material passage 14 can be completely stopped.

[0036] On the other hand, when restarting the operation of the auxiliary raw material supply unit 10B where the supply of the auxiliary raw material N has been stopped, the opening / closing motor 26 is rotationally operated in a predetermined direction, and as shown in FIG. 3, the cylindrical sleeve 22 is retracted to open the auxiliary raw material outlet 18d.

[0037] In the above-described embodiment, the case where the shutter device 20 is composed of the cylindrical sleeve 22, the transmission shaft 24, and the opening / closing motor 26 is shown. However, the shutter device 20 may be in any form as long as it can open and close the auxiliary raw material outlet 18d of the cylindrical body 18a in the auxiliary raw material cutting screw conveyor 18. For example, although not shown, a flap is provided near the auxiliary raw material outlet 18d, and the auxiliary raw material outlet 18d is opened and closed by operating this flap, or the above-described cylindrical sleeve 22 is driven by an air cylinder, a solenoid, etc., or a gear may be used for driving transmission to the cylindrical sleeve 22.

[0038] Also, the configuration of the above-described baffle plate 16 is not limited to that of the above-described embodiment. For example, a disk may be rotationally displaced via a shaft crossing the main raw material passage 12, and any configuration having a function of restricting the flow rate of the passing main raw material M may be appropriately adopted. Further, the diameter of the auxiliary raw material passage 14 may be made thinner to match the empty region Q so that the auxiliary raw material can be surely introduced from the auxiliary raw material passage 14 into the empty region Q. Of course, various modifications can be made within the scope that those skilled in the art can assume.

Explanation of Symbols

[0039] 10: Raw material supply device, 12: Main raw material passage, 12a: Downstream end opening, 14: Auxiliary raw material passage, 16: Baffle plate, 18: Screw conveyor for cutting out auxiliary raw material, 18a: Cylindrical body, 18b: Conveyor screw, 18c: Motor, 18d: Auxiliary raw material outlet, 20: Shutter device, 22: Cylindrical sleeve, 22a: Rail strip, 24: Transmission shaft, 24a: Contact portion, 24b: Magnet, 26: Opening and closing motor, M: Main raw material, N: Auxiliary raw material, P: Confluence connection portion, S: Main raw material passage space.

Claims

1. A raw material supply device that bifurcately connects the downstream end side of a main raw material passage (12) for feeding a certain amount of main raw material (M) downward and the downstream end side of a sub-raw material passage (14) for feeding a certain amount of sub-raw material (N) downward, and at this confluence connection part (P), the main raw material (M) and the sub-raw material (N) are made to merge and flow downward by their own weight. In this device, the main raw material passage (12) and the sub-raw material passage (14) are set to a downward gradient such that each raw material can flow downward by its own weight, and a baffle plate (16) is vertically provided downward from above the downstream end opening (12a) and is located near the downstream end opening (12a) of the main raw material passage (12). In the raw material supply device in which a main raw material passage space (S) is formed at least between the side surface of the baffle plate (16) and the downstream end opening (12a), On the upstream side of the sub-raw material passage (14), there is provided a cylindrical body (18a) constituting a sub-raw material conveyance path, a conveyance screw (18b) rotatably disposed inside the cylindrical body (18a), and a motor (18c) for rotating the conveyance screw (18b). A sub-raw material cutting screw conveyor (18) is provided for continuously discharging the sub-raw material (N) while metering it in a small amount from a sub-raw material outlet (18d) opened on the lower surface of the tip of the cylindrical body (18a). A shutter device (20) for opening and closing the sub-raw material outlet (18d) is attached to the tip side of the cylindrical body (18a) in the sub-raw material cutting screw conveyor (18). The raw material supply device is characterized by this.

2. In the raw material supply device according to Claim 1, The sub-raw material passage (14) is set to a steeper downward gradient than the main raw material passage (12). The raw material supply device is characterized by this.

3. In the raw material supply device according to Claim 1 or 2, The cross-sectional shape of the outlet of the main raw material passage (12) is circular, and the baffle plate (16) is disposed so as to be displaceable so as to cross the outlet of the main raw material passage (12) from above and below, and its lower part is formed to be narrower as it goes downward. The raw material supply device is characterized by this.

4. In the raw material supply device according to Claim 1 or 2, The shutter device (20) is A short tubular cylindrical sleeve (22) that slidably surrounds the outer periphery of the cylindrical body (18a), and a rail strip (22a) made of a ferromagnetic material is axially extended on its surface. The cylindrical sleeve (22) is A transmission shaft (24) provided with a contact portion (24a) that contacts the rail strip (22a) at the tip, and a magnet (24b) is attached to the surface of the contact portion (24a). A raw material supply device characterized by comprising an opening and closing motor (26) that rotates the transmission shaft (24) forward and backward.

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