JP2017209957A - Apparatus for stably supplying slight amount of granular material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for stably supplying a slight amount of a granular material, which is capable of stably and uniformly supplying a slight amount of an additive into a raw material hopper.SOLUTION: The present invention relates to an apparatus 10 for stably and uniformly supplying a slight amount of a granular material, in which a cylindrical body 16 constituting a raw material transportation path is provided with a raw material inlet 16a on an upper surface of a rear end part and a tip end lower surface is provided with a raw material exit 16b. A transportation screw 18 is provided rotatably inside of the cylindrical body 16. A cover member 20 is provided between the raw material inlet 16a and a base part 18a of the transportation screw 18 located immediately below the raw material inlet 16a, and covers a top surface 18b of the base part 18a and a riser side surface 18c of the base part 18a during rotation of the transportation screw 18.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a minute amount stable supply apparatus for a granular material capable of stably supplying a minute amount of a granular material including a resin raw material used in injection molding or extrusion molding.

  Many of the various types of resin raw materials (for example, main raw materials and various additives) used in injection molding and extrusion molding are processed into granules (pellet shape or short cylindrical shape), and these are processed according to the progress of molding. The required amount is charged into the raw material hopper, stirred in the raw material hopper so that the mixed state of various types of resin raw materials becomes uniform, supplied to the molding machine, and sent to the molding cylinder along with the rotation of the conveying screw of the molding machine.

  In such a molding field, recently, an additive material has appeared that significantly improves the performance of a molded product by adding a very small amount (for example, 1% or less) to a large amount of a main material. It is important that such a small amount of additive material is uniformly mixed with the main raw material in any part. If the mixing condition is uneven, 20-30% of the molded product is discarded as a quality defect. ing.

  2. Description of the Related Art Conventionally, a small-sized raw material supply device including a conveying screw has been widely used as a material for supplying a minute amount of a resin raw material (additive) to a raw material hopper of a molding machine (Patent Document 1).

  As shown in FIGS. 8 to 9, the conventional raw material supply apparatus 1 includes a cylindrical body 2 that constitutes a conveyance path for a resin raw material (additive) to be a raw material T, and a conveyance screw disposed inside the cylindrical body 2. 3 and a motor 4 and a hopper 5 for rotating the conveying screw 3, and a raw material charging port 2 a to which the hopper 5 is connected is formed on the upper surface of the rear end portion of the cylindrical body 2. A raw material outlet 2b that faces a raw material hopper of the molding machine is formed on the lower surface of the front end portion.

  When two or more kinds of raw materials T are supplied to the raw material hopper of the molding machine, the number of raw material supply devices 1 corresponding to the type of the raw material T are arranged above the raw material hopper, and the supply of each raw material supply device is performed. The addition ratio of the raw material T was adjusted by controlling the amount by the motor 4.

JP 2006-188302 A

  When the conventional raw material supply device 1 is to introduce a resin raw material (additive) that becomes a small amount of raw material T into the raw material hopper of the molding machine, the conveying screw 3 is rotated at a low speed to reduce the conveying speed of the raw material T. A small amount of the raw material T was continuously and fixedly extruded from the raw material outlet 2b of the cylindrical body 2 and charged into the raw material hopper of the molding machine.

  Since the raw material T is input from the raw material input port 2a of the cylindrical body 2, it falls toward the base of the conveying screw 3 looking directly under the raw material input port 2a. The dropped raw material T passes through both sides of the base of the transport screw 3 and accumulates at the bottom of the cylindrical body 2, and eventually the entire base of the transport screw 3 is filled with the raw material T. Then, with the rotation of the transport screw 3, the raw material T present around the base of the transport screw 3 is sent into the cylindrical body 2 by the blades of the transport screw 3.

  In this way, since the raw material T is transported between the blades of the transport screw 3 that rotates in the cylindrical body 2 and transports the raw material T over the entire upper, lower, left, and right circumferences without gaps. When the blades of the conveying screw 3 transfer the raw material T to the raw material outlet 2b on the lower surface of the cylindrical body 2, they enter the groove portion (portion indicated by A in the circle in FIG. 8) of the conveying screw 3 located at the raw material outlet 2b. The raw material T which has been discharged is discharged from the raw material outlet 2b, and the “avalanche phenomenon” is caused by the vibration at this time, and even the raw material T above the conveying screw 3 (the portion indicated by B in the circle in FIG. 8) Falls from the raw material outlet 2b toward the raw material hopper. When such an “avalanche phenomenon” is repeated in accordance with the rotation of the conveying screw 3, a large density occurs in the input of the raw material T.

  Such an “avalanche phenomenon” becomes more noticeable as the rotation speed of the conveying screw 3 is decreased, and when the rotation speed of the conveying screw 3 is extremely decreased in order to introduce a very small amount of the raw material T, the avalanche phenomenon of the conveying screw 3 is increased. Overlapping (clogging) of the particles of the raw material T in the groove of the blade influences to cause a more irregular “avalanche phenomenon”. In addition, FIG. 7 shows the result of measuring the actual weight of the raw material T discharged from the raw material outlet 2b when a small amount of supply is performed in the method of the present invention and the conventional method, and is shown by a broken line. In the conventional method, it can be seen that the variation (roughness) of the actual discharge amount is large with respect to the target discharge amount (0.2 g / 10 sec).

  Such charging unevenness at the time of charging the raw material has a great influence on the quality of the molded product, and it has not been eliminated even by heating and kneading in the injection or extrusion molding cylinder, causing the above-described molding failure.

  The present invention has been made in view of the above-mentioned problems, and its main problem is to provide a stable supply device for a particulate material capable of stably supplying a minute amount and a particulate material including a resin raw material. It is to be.

The invention described in claim 1 relates to a minute amount stable supply apparatus 10 for granular materials.
A raw material inlet 16a is formed on the upper surface of the rear end, and a raw material outlet 16b is formed on the lower surface of the front end.
A transport screw 18 rotatably disposed inside the cylindrical body 16;
Arranged between the raw material inlet 16a and the base 18a of the conveying screw 18 located immediately below the raw material inlet 16a, covers the upper surface 18b of the base 18a and the rising side surface 18c of the base 18a when the conveying screw 18 rotates. It is characterized by comprising a cover member 20.

The invention described in claim 2 is the particulate stable supply device 10 of claim 1,
The height H1 of the blade 29a of the base 18a of the conveying screw 18 is characterized by being formed lower than the height H2 of the blade 29b on the tip side from the base 18a.

The invention described in claim 3 is the micro-stable supply device 10 for particulate matter according to claim 1 or 2,
The rotation center P1 of the conveying screw 18 is provided on the bottom 16c side of the cylindrical body 16 from the axis P2 of the cylindrical body 16.

  In the particulate stable supply device 10 according to claim 1, since the cover member 20 is provided, the raw material T introduced from the raw material inlet 16a is obstructed by the cover member 20 and is an upper surface of the base 18a of the conveying screw 18. 18b, the entire amount passes through the side surface of the base portion 18a and falls into the resin reservoir 16d of the cylindrical body 16 just below the base portion 18a, eventually exceeds the upper portion of the cover member 20, and the entire cover member 20 is made of the raw material T. The resin reservoir 16d is filled with the raw material T until it is buried. At this time, a space where the raw material T does not exist is created between the base 18a of the transport screw 18 and the cover member 20, and in other portions (regions not covered by the cover member 20), The base 18a is in contact with the raw material T. Therefore, the raw material T is not transported while being placed on the upper surface of the base 18a of the transport screw 18.

  The raw material T that has fallen into the resin reservoir 16d is scraped by the transport screw 18 into the cover member 20 on the upper surface of the transport screw 18 while the lower raw material T that is not covered by the cover member 20 of the transport screw 18 is swept up. The raw material T inside the cylinder 16 is pressed from the opening 16e, and the pressed and conveyed raw material T is conveyed along the vicinity of the bottom 16c of the cylindrical body 16. Here, if the height H1 of the blades 29a of the base 18a of the conveying screw 18 is formed lower than the height H2 of the blades 29b on the tip side of the base 18a, the lifting force of the raw material T at the base 18a is reduced. The raw material T that rides on the upper surface 18b of the base 18a and is conveyed does not occur.

  From the above, the raw material T conveyed by the conveying screw 18 is not fully filled between the cylinder 16 and the conveying screw 18, and is near the bottom 16 c of the cylinder 16 (below the groove of the conveying screw 18). Will exist only in

  As described above, according to the present invention, the raw material T is wound up on the surface of the blade 29a of the base 18a of the transport screw 18 and is fed into the gap between the rising side surface 18c and the cover member 20. A small amount of the raw material T is charged into the groove between the blades 29a and 29b. When the raw material T distributed to the bottom of the groove between the blades 29a and 29b of the conveying screw 18 reaches the raw material outlet 16b, the upper region of the blade 29b (at the tip of the base 18a) of the conveying screw 18 The raw material T does not exist, and the “avalanche phenomenon” as described in the prior art is less likely to occur.

  In addition, in the present invention, the raw material T is not fully filled between the cylindrical body 16 and the conveying screw 18 and the filling density of the raw material T is small, so that the conventional method (between the cylindrical body 16 and the conveying screw 18). When the conveying screw 18 is rotated at the same rotational speed as the material T is fully filled), the material T discharged from the material outlet 16b is naturally reduced as compared with the conventional method. In other words, it is necessary to increase the rotational speed of the transport screw 18 (the rotational speed of the transport screw 18 can be increased) in order to obtain the same supply amount as in the conventional method. If the number of rotations of the conveying screw 18 can be increased, the time interval of the density of the raw material T due to the influence of the slope of the blades of the conveying screw 18 can be reduced, and the variation in density can be suppressed. Combined with the avalanche phenomenon becoming difficult to occur, it becomes possible to stably supply the raw material T as a granular material in a minute amount.

  In addition, when the clearance between the bottom 16c of the cylindrical body 16 and the blade 29b of the conveyance screw 18 (on the tip side from the base 18a) is large, there is a possibility that the raw material T may be caught or a conveyance error may occur. The raw material T existing between the blades 29b will have a large amount (roughness). In this respect, if the rotation center P1 of the conveying screw 18 is provided on the bottom 16c side of the cylindrical body 16 from the axis P2 of the cylindrical body 16 as in the invention described in claim 3, the bottom 16c of the cylindrical body 16 is provided. And the blades 29b of the conveying screw 18 are reduced, so that the raw material T is not caught and a conveyance error does not occur, and the raw material T collected in the vicinity of the bottom 16c of the cylindrical body 16 is more reliably and stable. Can be extruded.

It is a front view which shows the relationship between the molding machine and raw material supply apparatus in this invention. FIG. 2 is an enlarged longitudinal sectional view showing the raw material supply apparatus of FIG. 1. FIG. 3 is a plan view of FIG. 2. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. It is CC sectional drawing of FIG. It is a figure which shows the result of having measured the quantity by which the raw material was actually discharged | emitted from the raw material exit when a trace amount supply was each performed with the method of this invention and the conventional method. It is a figure which shows the conventional raw material supply apparatus. It is a schematic diagram of the avalanche phenomenon.

  Hereinafter, the present invention will be described in detail according to illustrated embodiments. As shown in FIG. 1 to FIG. 2, the particulate stable supply device 10 is a granular (pellet-like or short cylindrical) raw material (resin pellets in this embodiment) T used in injection molding or extrusion molding. A cylinder 16 constituting the material conveyance path, a conveyance screw 18 rotatably disposed inside the cylinder 16, and a motor that rotates the conveyance screw 18 are supplied to the material hopper 37 of the molding machine S. M (or a rotational force transmission member such as a gear), a cover member 20 that covers the base 18a of the conveying screw 18, and a raw material supply hopper 22 that receives the raw material T.

  The cylindrical body 16 is a tubular member having a circular cross section. A plate-like support 24 that rotatably supports the conveying screw 18 is provided at the tip of the cylindrical body 16, and a raw material outlet 16 b is provided at the lower surface of the tip. Is formed.

  In addition, a raw material inlet 16a is formed on the upper surface of the rear end portion of the cylindrical body 16, and a raw material supply hopper 22 is connected to the raw material inlet 16a. A resin reservoir 16d is provided immediately below the raw material inlet 16a. In FIG. 2, the resin reservoir 16d is described as being formed one step below the bottom 16c of the cylinder 16 so as to be clear, but between the base 18a of the conveying screw 18 and the bottom of the resin reservoir 16d. Any position can be set as long as the existing raw material T can be effectively lifted and fed into the cylinder 16. For example, the bottom of the resin reservoir 16 d is flush with the bottom 16 c of the cylinder 16 (or You may set so that it may become (above bottom 16c). An opening 16e of a cylinder hole 16s of the cylinder 16 is opened on the front surface of the resin reservoir 16d, and a conveying screw 18 is inserted through the cylinder hole 16s.

  As shown in FIG. 2, the conveying screw 18 has a rod-shaped rotating shaft 28 and a blade 29 formed in a spiral shape on the outer surface of the rotating shaft 28, and the blade 29 is a base 18 a of the conveying screw 18. The blade 29a and the blade 29b on the tip side from the base portion 18a are separated from each other, and the height H1 of the blade 29a of the base portion 18a is formed lower than the height H2 of the blade 29b on the tip side from the base portion 18a.

  Here, as can be seen from FIG. 2, the “base portion 18 a of the conveying screw 18” is a portion that protrudes toward the resin reservoir 16 d with the opening 16 e as a boundary. The boundary between the heights H1 and H2 of the blades 29 is not necessarily coincident with the opening 16e, and can be appropriately selected depending on the shape of the raw material T and the transport amount. The height of H1 is appropriately adjusted depending on the shape and supply amount of the raw material T.

  The cover member 20 is a curved plate having an arc-shaped cross section obtained by cutting off a part of a cylinder, and is disposed between the raw material inlet 16a and the base 18a of the conveying screw 18 positioned immediately below the raw material inlet 16a. The base 18a of the conveying screw 18 covers at least the entire portion immediately below the raw material inlet 16a from above. There is a gap between the raw material inlet 16a and the cover member 20, and the raw material T falls into the resin reservoir 16d through the gap.

  As can be seen from FIG. 4, both sides of the cover member 20 cover the upper surface 18 b of the base portion 18 a and the ascending side surface 18 c of the base portion 18 a when the transport screw 18 rotates. That is, the right portion 20a (right side as viewed from above) covering the rising side surface 18c of the base portion 18a is longer than the left portion 20b and extends below the rotation center P1 of the transport screw 18. In the present embodiment, as described above, the lower end of the right side portion 20a of the cover member 20 extends below the rotation center P1 of the transport screw 18, but the function of the right side portion 20a of the cover member 20 is as follows. If the raw material T scraped by the blades 29a of the 18 base portions 18a can be fed into the gap between the right portion 20a of the cover member 20 and the base portion 18a of the conveying screw 18, the right portion 20a can be satisfied. May be located at the same height as the rotation center P1 of the conveying screw 18 or slightly above the rotation center P1.

  On the other hand, the left portion 20b only needs to cover the raw material T falling from above so as not to be placed on the upper surface 18b of the base portion 18a.

  The conveyance screw 18 may be set coaxially with the cylinder 16, but the rotation center P <b> 1 of the conveyance screw 18 is located on the bottom 16 c side of the cylinder 16 with respect to the axis P <b> 2 of the cylinder 16 as shown in FIG. 4. You may provide so that it may become. In this case, the interval W between the outer periphery of the blade 29 b on the tip side of the base 18 a of the conveying screw 18 and the bottom 16 c of the cylinder hole 16 s of the cylindrical body 16 is formed narrower than the particle size of the raw material T.

  When the raw material T is supplied to the raw material hopper 37 of the molding machine S using such a granular micro stable supply device 10, the raw material outlet 16b of the micro stable supply device 10 is positioned with respect to the raw material hopper 37, A small amount of raw material T is supplied to the raw material hopper 37 supplied with a large amount of main raw material without excess or deficiency. Alternatively, a raw material having a desired mixing ratio to the forming cylinder without installing a stirrer in the raw material hopper 37 by supplying a small amount of the raw material T in time synchronization with the supply of a large amount of the main raw material. T can be supplied.

  That is, the raw material T charged into the resin reservoir 16d of the trace stable supply device 10 is filled in an amount exceeding the raw material inlet 16a. However, the presence of the cover member 20 allows the upper surface 18b of the base 18a of the conveying screw 18 and A space without the raw material T is formed between the ascending side surface 18c and the cover member 20, and the lower surface of the base 18a where the cover member does not exist is in contact with the raw material T. 29a, the raw material T is sandwiched between the right portion 20a of the cover member 20 and the lower blade 29a and slightly lifted (in other words, to the side surface of the base portion 18a). Advance. The state is shown in FIGS.

  The raw material T, which is pushed along the rotation of the conveying screw 18 by the blades 29b and sent along the bottom surface 16c of the cylindrical body 16 and the side surface on the right side when viewed from the paper surface on the scraping side, When it reaches 16b, it falls by an amount set in accordance with the rotation of the conveying screw 18 without excess or deficiency.

(Example)
Inventors measured the actual weight of the raw material T discharged | emitted from the raw material outlet 16b using the trace stable supply apparatus 10 which concerns on a present Example, and performed the test which confirms the effect of this invention. As the raw material T, a pellet-shaped resin raw material (particle diameter 3 to 4 mm) was used. Moreover, the rotation speed of the conveyance screw 18 was set so that the target value of the resin supply amount was 0.2 g / 10 sec. As a comparison test, the same test was performed using the conventional micro stable supply apparatus 1. The test results at this time are shown in FIG.

  As can be seen from FIG. 7, when the micro-stable supply apparatus 10 according to the present invention is used, the variation in the supply amount of the raw material T can be remarkably suppressed as compared with the conventional method, and the granular material can be supplied minutely and stably. I found out that

  The present invention can be applied to any material as long as it is a granular material. In addition to resin raw materials, for example, foods such as red beans and soybeans, and granular materials such as metal pellets can be used. The present invention can be used in general fields where a minute amount and a stable supply are required.

DESCRIPTION OF SYMBOLS 1: Conventional raw material supply apparatus, 2: Cylindrical body, 2a: Raw material input port, 2b: Raw material outlet, 3: Transfer screw, 4: Motor, 5: Hopper, 10: Granular stable supply apparatus, 16: Cylinder Body, 16a: raw material inlet, 16b: raw material outlet, 16c: bottom, 16d: resin reservoir, 16e: opening, 16s: cylinder hole, 18: conveying screw, 18a: base, 18b: upper surface, 18c: ascending side surface, 20: cover member, 20a: right side portion, 20b: left side portion, 22: raw material supply hopper, 24: support, 28: rotating shaft, 29: blade, 29a: blade on the base, 29b: blade on the tip side from the base, 37: Raw material hopper, H1 / H2: Blade height, M: Motor, P1: Rotation center of conveyance screw, P2: Center axis of cylinder, S: Molding machine, T: Raw material, W: Spacing

Claims (3)

A raw material inlet is formed on the upper surface of the rear end portion, a raw material outlet is formed on the lower surface of the front end, and a cylindrical body constituting the raw material conveyance path;
A conveying screw rotatably disposed inside the cylindrical body;
A cover member that is disposed between the raw material inlet and the base of the transport screw located immediately below the raw material inlet and covers the upper surface of the base and the rising side surface of the base when the transport screw rotates. A stable supply device for a minute amount of granular material. In the particulate stable supply apparatus of claim 1,
The granular microstable supply device according to claim 1, wherein the height of the blades at the base of the conveying screw is lower than the height of the blades at the tip side of the base. In the minute amount stable supply apparatus of the granular material of Claim 1 or 2,
The rotational stable center of the said conveyance screw is provided in the bottom side of the said cylindrical body from the axial center of the said cylindrical body, The trace amount stable supply apparatus of the granular material characterized by the above-mentioned.

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