JP4824003B2 - Plastic pellet forming equipment - Google Patents

Description

  In the present invention, plastic waste materials such as runners and defective molded products discharged from a molding machine are pulverized, granulated and melted at the molding site at a plastic injection molding site. The present invention relates to a plastic pellet forming apparatus used for use.

Conventionally, plastic waste materials such as runners and defective molded products discharged from a molding machine are pulverized and mixed with virgin materials at a plastic injection molding site and reused as molding materials for plastic products.
Among them, in the field of plastic molding called so-called precision stable molding, as described above, simply pulverizing plastic waste material contains fine powder and irregularly sized pulverized particles. Is used for plastic molding as it is, there is a risk that the above-described precision and stable molding of plastics may be hindered.
Therefore, in the case of carrying out precision stable molding of the above-mentioned plastic, a pellet forming apparatus for pelletizing the pulverized material once pulverized into a certain size is required.

  Generally, the pellet forming apparatus for pelletizing the pulverized material continuously extrudes molten plastic from a hot rotating screw type extrusion means through a die as a strand. The strand extruded through the die is sequentially cut into a certain length by a cutter and pelletized.

Alternatively, as described above, the uncooled strand extruded from the die has an adhesive force, and when it is directly cut into a plurality of pellets, the plurality of pellets stick to each other. And become large.
Therefore, a normal pellet forming apparatus is provided with a water tank in which cooling water is stored for cooling and solidifying a strand in a molten state extruded from a die. The strand extruded from the die is cooled and solidified through the water tank. Thereafter, the cooled and solidified strand is wound around a pinch roller, and the strand is sequentially cut into a certain length by a cutter and pelletized.

As described above, this generally used pellet forming apparatus is equipped with a large hot rotating screw type extrusion means, a water-cooled large water tank for cooling the strand, etc., and takes a large installation area and is expensive. .
Therefore, it is not suitable for use in a plastic injection molding site with a small installation area.

  In addition, when the plastic waste material that is normally used is switched to a different type and different color plastic waste material, the cooling water is stored in the newly switched different type and different color cooling strand. This requires a lot of time and labor because it requires troublesome and troublesome setting work to pass through the inside of the water tank. Further, even when the middle part of the strand is interrupted for some reason and is cut, a troublesome setting work is required for passing the strand through a water tank or the like in which cooling water is stored.

  Furthermore, since the above-described normally used pellet forming apparatus is a water-cooling method in which the strand is cooled and solidified through a water tank in which cooling water is stored, the cooled and solidified strand is cut into pellets, and then the pellets are dried. Therefore, a post-process is required, and accordingly, the equipment becomes large and expensive.

  For these reasons, the above-described normally used water-cooled pellet forming apparatus is not suitable for installation and use at the plastic molding site.

As a pellet forming apparatus that eliminates these difficulties, an air-cooled type, which eliminates a large water tank that cools and solidifies the strands, and cools and solidifies the molten strands extruded from the die by the atmosphere, Japanese Patent Laid-Open No. 9-29739 There are apparatuses described in Japanese Patent Laid-Open No. 2001-88196 and Japanese Patent Laid-Open No. 2002-59419.
JP-A-9-29739 Japanese Patent Laid-Open No. 9-193158 JP 2001-88196 A JP 2002-59419 A

Among them, in the apparatus described in JP-A-9-29739, a strand in a molten state extruded from a hot rotating screw through a die is guided in a guide group and introduced into an air-cooled bush / mechanical element. It is structured to be cooled.
For this reason, in this apparatus, as described in paragraph No. 0002 of JP-A-9-193158, the strand in the uncooled molten state remains in a soft state in which it is not cooled immediately after being extruded from the die. In this case, the diameter of the strand guided in the guide group is not uniform and becomes unstable.
Also, in this apparatus, the air is sent around the melted strand passing through the inside of the bush / mechanical element, the cooling efficiency when cooling the strand is poor, and the bush is not cooled and solidified sufficiently. -There were many situations where it was discharged outside the mechanical element.
The cause is that much of the cooling air sent to the inside of the bushing / mechanism element does not circulate around the strand passing through the inside of the bushing / mechanism element, and the upper end opening and lower end of the bushing / mechanism element are wide open This is because the leakage from the opening to the outside of the bushing / mechanical element occurs. Moreover, since it cools using the air of normal temperature state, when atmospheric temperature is high, it will fall into the situation where a strand is not fully cooled and solidified.
Furthermore, in this apparatus, when strand formation is attempted from a state where the die temperature is low, the uncooled soft strand tip pushed out from the strand forming path of the die adheres to the end surface of the die and bends in a ring shape. I have. The end of the strand bent in the ring shape was not smoothly introduced into the inside of the bushing / mechanism element through the guide group, but blocked the upper end opening of the bushing / mechanism element. And it has become impossible to operate the pellet forming apparatus continuously.

The apparatus described in Japanese Patent Laid-Open No. 2001-88196 has a structure in which air is blown from a blower onto a molten strand extruded from a die to cool and solidify the strand. On the opposite side of the blower, a wire mesh is stretched across the strand passage. And it has the structure where the strand receives the wind pressure of the air sent out from an air blower by the wire mesh, and prevents bending largely.
In this device, most of the cooling air sent out from the blower reliably contacts the uncooled soft strand and does not circulate around the strand. It will pass in vain. Therefore, there is a difficulty that the strand is not efficiently cooled and solidified.
Therefore, in this apparatus, it is necessary to set a long passage for passing the cooling air from the blower and let the uncooled and weak strands pass, and to continue cooling the strands for a long time for a long distance. For this reason, the strand in the soft state has been suspended for a long time below the die, and the strand located near the die has been elongated for a long time due to the weight of the long suspended strand. And there was a difficulty that the outer diameter of the strand extruded from the die was greatly out of order.
Moreover, in this apparatus, since the strand in a molten state is cooled by air at normal temperature, the strands are not sufficiently cooled and solidified due to the influence of fluctuations in the atmospheric temperature.

In the apparatus described in Japanese Patent Laid-Open No. 2002-59419, a guide roller is provided in the middle of the strand passage in order to extend the cooling time of the strand in the molten state. And the strand in the uncooled soft state pushed out from the die is circulated through the guide roller around the V-shape for a long distance. The strand is sufficiently cooled and solidified with air over time.
In this apparatus, at the start of the operation, a troublesome and troublesome setting operation such as winding the melted strand extruded from the die around the guide roller is necessary. In addition, since the guide roller is added, the apparatus becomes large, and it is not suitable for use in a plastic molding site where the installation area is desired to be reduced.

  The present invention is a pellet forming apparatus that can solve such a problem and is installed in a plastic molding site where the installation area is desired to be kept small, and sequentially pulverized plastic waste material into a certain size. It is an object of the present invention to provide an air-cooled plastic pellet forming apparatus capable of efficiently and surely sufficiently cooling and solidifying an extruded strand in an uncooled molten state.

In order to achieve such an object, the plastic pellet forming apparatus of the present invention includes a molten plastic extrusion means for melting and extruding a plastic material for pellet formation, and a strand forming path for the molten plastic extruded from the extrusion means. A die that extrudes the strand vertically downward from the lower end of the strand forming path, and a cylindrical guide that stands vertically immediately below the lower end of the strand forming path of the die, and is extruded from the die. After the introduced strand is introduced from the upper end opening and passed through the inside thereof, the cylindrical guide discharged from the lower end opening and the strand discharged from the lower end opening of the cylindrical guide have a certain length In addition, it has a structure having a cutter for strand cutting that is sequentially cut and aligned.
Then, the strand cooling means sends air-cooling refrigerant from the upper end opening of the cylindrical guide to the inside of the cylindrical guide so as not to leak into the outside air, and passes through the inside of the cylindrical guide. After circulating around the inside strand, the structure is discharged from the lower end opening of the cylindrical guide to the outside of the cylindrical guide.

  In the plastic pellet forming apparatus having such a configuration, the cooling means for the strand prevents all of the air-cooling refrigerant from leaking into the outside air, and the inside of the cylindrical guide from the upper end opening of the cylindrical guide. Can be sent efficiently and reliably. Then, almost all of the air-cooling refrigerant sent to the inside of the cylindrical guide does not leak to the outside of the cylindrical guide, and the strand passing through the inside of the cylindrical guide having no opening such as a hole in the side wall. Can be contacted. The air-cooling refrigerant sent to the inside of the cylindrical guide can be efficiently and reliably circulated around the strand passing through the inside of the cylindrical guide. The strand passing through the inner side of the cylindrical guide can be cooled and solidified efficiently and reliably in a short time by the refrigerant circulating around the strand.

In the plastic pellet forming apparatus according to the present invention, the die divides and introduces the molten plastic extruded from the extrusion means into a plurality of strand forming paths, and forms a plurality of strands connected to the plurality of strand forming paths. It is preferable that the strands be extruded vertically downward from the lower end of the road.
In addition, the cylindrical guide is a plurality of cylindrical guides that stand vertically directly below the lower ends of the plurality of strand forming paths, and a strand that is extruded vertically downward from the lower ends of the strand forming paths, After being introduced from the inside and passing through the inside of the cylindrical guide, it is preferable to comprise a plurality of cylindrical guides discharged from the lower end opening to the outside of the cylindrical guide.

In the plastic pellet forming apparatus having such a configuration, the molten plastic extruded from the extrusion means can be branched and introduced into two or more plural strand forming paths provided in the die instead of one. . Then, the strands can be simultaneously extruded vertically downward from the lower ends of two or more of the plurality of strand forming paths connected to the plurality of strand forming paths. And the multiple strand for pellet formation can be formed simultaneously in a short time.
In addition, each of the plurality of strands simultaneously formed in such a short period of time is arranged at the upper end of each of the plurality of cylindrical guides standing upright directly below the lower ends of the plurality of strand forming paths of the die. It can be introduced from the opening. Then, an air cooling refrigerant is circulated by the cooling means around the strands that respectively pass through the insides of the plurality of cylindrical guides, and the plurality of strands can be simultaneously cooled and solidified. The solidified strand can be formed into pellets by sequentially cutting the strands into a certain length with a cutter for strand cutting. And many pellets can be formed simultaneously in a short time.
Further, the molten plastic extruded from the extrusion means is formed by diverging into a plurality of strands by a die, and the plurality of strands are separately passed through the inside of the plurality of cylindrical guides to thereby form the plurality of cylindrical shapes. It is possible to improve the efficiency of cooling the strands in the molten state passing through the inside of the guide by the air cooling type cooling means. And a plurality of strands cooled and solidified for pellet formation can be efficiently formed simultaneously in a short time.

In the plastic pellet forming apparatus of the present invention, the air cooling refrigerant may be cooling air or room temperature air.
When the air-cooling refrigerant is cooling air, it is possible to reliably improve the cooling efficiency when the strand passing through the inside of the cylindrical guide is cooled by the cooling means, as compared with the room temperature air. Further, when the air cooling refrigerant is cooling air, the strand passing through the inside of the cylindrical guide is stably and surely cooled by the cooling means without being affected by the change in the atmospheric temperature. It can be solidified.

  In the plastic pellet forming apparatus of the present invention, a squeezing nozzle for forming a strand having a tip inner diameter smaller than the inner diameter of the cylindrical guide is provided in communication with the strand forming path at the lower end of the strand forming path of the die. It is preferable to adopt a structure in which the tip of the throttle nozzle is introduced inside the upper end opening of the cylindrical guide in a suspended state in contact with the inner wall of the cylindrical guide.

In the plastic pellet forming apparatus having such a configuration, the strand in the molten state that is extruded from the die is placed inside the squeezing nozzle for forming the strand that is provided in communication with the strand forming path at the lower end of the strand forming path of the die. By passing, the outer diameter of the strand can be narrowed down to a smaller diameter to the inner diameter of the stop nozzle tip having a smaller diameter than the inner diameter of the cylindrical guide. Next, the strand narrowed down to the small diameter can be smoothly introduced from the upper end opening to the inside of the cylindrical guide having an inner diameter larger than that, without causing resistance.
At that time, since the tip of the throttle nozzle is introduced inside the upper end opening of the cylindrical guide in a suspended state without contact with the inner wall of the cylindrical guide, the melt having adhesive force pushed out from the tip of the throttle nozzle The strand in the state can be smoothly introduced without being caught by being caught in the substantially center inside the cylindrical guide without being attached to the inner wall of the cylindrical guide.

As described above, according to the plastic pellet forming apparatus of the present invention, it is possible to efficiently and surely cool and solidify a strand in a molten state extruded from a die in a short time. And the molten plastic extruded from an extrusion means can be efficiently formed in many pellets within a short time.
Also, because it is air-cooled, there is no need for a large water-cooled water tank that cools the strands or the troublesome and troublesome setting of the strands, making it suitable for easy use on plastic forming sites with a small installation area. A plastic pellet forming apparatus can be provided.

Next, embodiments of the present invention will be described with reference to the drawings.
1 and 2 show a preferred embodiment of the plastic pellet forming apparatus of the present invention, FIG. 1 is a front sectional view thereof, and FIG. 2 is a bottom view of a portion where the cutter is provided. Hereinafter, the plastic pellet forming apparatus will be described.

As shown in FIG. 1, this plastic pellet forming apparatus is provided with a molten plastic extrusion means 10 on the top thereof for melting and extruding a plastic material for pellet formation.
The pushing means 10 has a spiral groove 14 formed in the lower end surface of a cylindrical rotating body (disk screw) 12 that rotates in the horizontal direction from its center to its periphery. Then, as the rotating body 12 is rotated by an electric motor (geared motor) 16 with a reduction gear, pellet forming is fed from the hopper 18 provided outside the rotating body 12 to the periphery of the lower end surface of the rotating body 12. While the plastic material 20 is gradually heated and melted by the electric heater 30 via the heating cylinder 32 and the rotating body 12, the center of the lower end surface of the rotating body 12 extends along the inside of the spiral groove 14 on the lower end surface of the rotating body. It has a structure that continues to be pumped. The molten plastic pumped to the center of the lower end surface of the rotator 12 has a structure in which the molten plastic is sequentially and continuously extruded below the rotator 12 from an extrusion port 19 provided at the center of the lower end surface of the rotator 12.
The pushing means 10 has a vertical structure in which a spiral groove 14 is formed on the lower end surface of a cylindrical rotating body 12, and is suitable for narrowing the installation area of the plastic pellet forming apparatus. This extrusion means 10 is also used in the injection molding apparatus described in Japanese Patent No. 3418639.

  Below the rotating body 12, a disk-shaped die 40 is disposed so that the upper end surface thereof is substantially in contact with the lower end surface of the rotating body 12 with little gap so as not to prevent the rotation of the rotating body 12. Then, the molten plastic that continues to be extruded from the extrusion port 19 at the center of the lower end surface of the rotating body is sequentially pushed into the strand formation path 44 provided in the die through the introduction port 42 provided in the center of the die 40, and the strand 50 is continuously formed. The strand 50 that is continuously formed by being pushed into the strand forming path 44 has a structure in which the strand 50 is continuously extruded from the lower end 46 of the strand forming path provided on the lower end surface of the die 40 in a vertically downward direction corresponding to the direction of gravity.

  Immediately below the lower end 46 of the die strand forming path, a cylindrical guide 60 having no opening such as a hole in the side wall is arranged in a vertically standing state. Then, after the strand 50 in a molten state that continues to be pushed out from the lower end 46 of the strand forming path of the die is introduced from the upper end opening 62 of the cylindrical guide and passed through the inner side of the cylindrical guide 60, the cylindrical shape The guide is continuously discharged from the lower end opening 64 of the guide downward to the cylindrical guide 60.

  The upper and lower ends of the cylindrical guide 60 are fixed and supported by the apparatus frame 70. A heat insulating plate 80 is interposed between the device frame 70 and the die 40. The heat of the electric heater 30 is prevented from being transmitted to the cylindrical guide 60 via the device frame 70.

At the lower end of the cylindrical guide 60, there is a cutter 90 for cutting strands, which sequentially cuts the strands 50 continuously discharged from the lower end opening 64 of the cylindrical guide below the cylindrical guide 60 to a predetermined length. 90 is provided. The cutter 90 has a structure in which a fixed blade 92 and a rotary blade 94 are combined as shown in FIGS. The fixed blade 92 has a substantially disk shape and is fixed to the lower end of the cylindrical guide 60. The rotary blade 94 is substantially rod-shaped and is rotated around the center of the lower end surface of the rotary blade 94 by a variable speed electric motor 96 provided inside the device frame 70 along the lower end surface of the fixed blade 92 having a substantially disc shape. It has a structure to let you. And the rotary blade 94 which rotates the strand 50 discharged | emitted continuously below the fixed blade 92 along the lower end surface of the fixed blade 92 through the hole 93 provided in the fixed blade continuous with the lower end opening 64 of the cylindrical guide. Therefore, it is structured to sequentially cut to a certain length.
At that time, the rotational speed of the variable speed electric motor 96 is adjusted, and the rotational speed of the rotary blade 94 rotated along the lower end surface of the fixed blade 94 is discharged through the hole 93 to the lower side of the fixed blade 92. It has a structure that can be adjusted slowly according to the speed. And it has the structure which can adjust the length of the pellet cut | disconnected and formed from the strand 50 by the cutter 90 which consists of the fixed blade 92 and the rotary blade 94 to desired fixed length.

The above configuration is the same as that of a conventional general plastic pellet forming apparatus. In the pellet forming apparatus shown in FIGS. 1 and 2, the strand cooling means 100 leaks air-cooling refrigerant into the outside air. After being fed into the cylindrical guide 60 from the upper end opening 62 of the cylindrical guide and contacting the strand 50 passing through the inner side of the cylindrical guide 60, the periphery of the strand 50 is circulated. The cylindrical guide 60 is discharged from the lower end opening 64 to the outside of the cylindrical guide 60.
Specifically, as shown in FIG. 1, an air cooling unit is connected to a device frame upper end (cylindrical pipe holding plate) 72 that supports the upper end of the cylindrical guide 60 through a refrigerant introduction port 74 provided on the lower surface of the center. The refrigerant passage 76 that feeds the refrigerant into the cylindrical guide 60 from the upper end opening 62 of the cylindrical guide so as not to leak into the outside air has an airtightness with the outside of the apparatus frame 70 and the cylindrical guide 60. It is provided.
As shown in FIG. 1, the refrigerant introduction port 74 provided at the upper end 72 of the apparatus frame continuously supplies refrigerant for cooling air (air) to the refrigerant passage 76 provided at the upper end 72 of the apparatus frame. Means 110 are coupled.
The refrigerant supply means 110 includes a blower fan (not shown) and a refrigerant introduction path 112 that sends air refrigerant sent out from the fan to the refrigerant introduction port 74. The cooling air (refrigerant) is continuously fed into the upper end opening 62 of the cylindrical guide through the refrigerant introduction passage 112 and the refrigerant passage 76 so as not to leak into the outside air. .

The pellet forming apparatus shown in FIG. 1 and FIG. 2 is configured as described above, and in this pellet forming apparatus, the electric heater 30 rotates the rotating body 12 with the electric motor 16 with a reduction gear. The rotating body 12 can be continuously heated to a desired temperature. Then, the plastic material 20 such as crushed plastic waste material and virgin material carried into the hopper 18 provided on the outer side of the rotating body 12 is passed through the spiral groove 14 on the lower end surface of the rotating body from the periphery of the lower end surface of the rotating body 12. Can continue to pump to the center. At the same time, the plastic material 20 that continues to be pumped into the center of the lower end surface of the rotating body 12 is gradually heated by the electric heater 30 through the heating cylinder 32 and the rotating body 12. Can continue to melt. Then, the molten plastic in a state in which the plastic material 20 is melted can be sequentially and sequentially extruded from the extrusion port 19 provided at the center of the lower end surface of the rotating body 12 to the lower side of the rotating body 12.
The molten plastic continuously extruded below the rotating body 12 can be continuously formed into the strand 50 by sequentially pushing into the strand forming path 44 of the die through the inlet 42 provided in the center of the die. The strand 50 continuously formed by being pushed into the strand forming path 44 can be continuously and vertically extruded from the strand forming path lower end 46 on the lower end surface of the die to the lower side of the die 40 that hits the direction of gravity.
The strand 50 in an uncooled molten state continuously pushed out from the lower end 46 of the strand forming path of the die is introduced into the cylindrical guide 60 disposed immediately below the lower end 46 of the strand forming path from the upper end opening 62, and The inside of the cylindrical guide 60 can be passed.
At that time, since the strand 50 is discharged vertically downward from the lower end 46 of the strand formation path, which corresponds to the direction of gravity, the strand 50 having the adhesive force stands upright directly below the lower end 46 of the strand formation path. Thus, it can be smoothly introduced from the upper end opening 62 to the center of the inner side of the cylindrical guide 60 that is arranged without being attached to the inner wall of the cylindrical guide 60.
The strand 50 that has passed through the inside of the cylindrical guide 60 can be continuously discharged downward from the lower end opening 64 of the cylindrical guide 60.

  When passing the strand 50 extruded from the die 40 in the molten state through the inside of the cylindrical guide 60, a blower fan (not shown) of the refrigerant feeding means 110 is driven to cool the refrigerant (air) for air cooling. Can be fed into the cylindrical guide 60 from the upper end opening 62 of the cylindrical guide through the airtight refrigerant passage 76 provided in the upper end 72 of the apparatus frame so as not to leak into the outside air. . Then, almost all of the air cooling refrigerant does not leak to the outside of the cylindrical guide 60, and reliably contacts the strand 50 passing through the inside of the cylindrical guide 60 having no opening such as a hole in the side wall. It is possible to circulate around the strand 50 while making it happen. The strand 50 in the molten state passing through the inside of the cylindrical guide 60 can be cooled and solidified efficiently and reliably by the air-cooling refrigerant. The cooled and solidified strand 50 can be continuously discharged below the cylindrical guide 60 from the lower end opening 64 of the cylindrical guide.

  At that time, the heat insulating plate 80 can prevent the heat of the electric heater 30 from being transmitted to the cylindrical guide 60 via the device frame 70. And it can prevent that the heat | fever of the electric heater 30 reduces the cooling efficiency of the strand 50 by the air-cooling type cooling means 100 currently passing the cylindrical guide 60 inside.

  The strand 50 continuously discharged from the lower end opening 64 of the cylindrical guide to the lower side of the cylindrical guide 60 can be sequentially cut to a certain length by the cutter 90 provided at the lower end of the cylindrical guide 60. And many pellets formed by cutting the solidified strands into a certain length can be formed one after another.

In this pellet forming apparatus, as shown in FIG. 1, the dice 40 branches the molten plastic extruded from the extrusion means 10 into a plurality of strand forming paths 44 and feeds the plurality of strand forming paths 44. It is preferable to have a plurality of branched strand forming paths 44 that push the strand 50 vertically downward from each of the lower ends 46 of the plurality of strand forming paths.
At the same time, as shown in FIG. 1, the cylindrical guide 60 is composed of a plurality of cylindrical guides 60 erected vertically directly below the lower ends 46 of the strand forming paths of the plurality of strand forming paths provided in the die 40. It is preferable. Then, a plurality of strands 50 respectively extruded vertically downward from the plurality of strand forming path lower ends 46 were introduced from the upper end opening 62 of the cylindrical guide immediately below, and passed through the inside of the cylindrical guide 60. Thereafter, it is preferable that the cylindrical guide 60 is composed of a plurality of cylindrical guides 60 that are discharged downward from the lower end opening 64 of the cylindrical guide.

And it is good to send the molten plastic extruded from the extrusion means 10 to each of the several strand formation path 44 branched and provided to the die | dye 40. FIG. Then, the strands 50 may be simultaneously extruded vertically below the strand formation path lower end 46 from each of the plurality of strand formation path lower ends 46 on the lower end surface of the die continuous with the plurality of strand formation paths 44. And it is good to be able to form simultaneously the strand 50 for several pellet formation in a short time.
At the same time, the plurality of strands 50 that are simultaneously formed in a short time in this manner are placed inside the plurality of cylindrical guides 60 that stand vertically below the lower ends 46 of the plurality of strand forming paths of the die, respectively. It may be introduced from the upper end opening 62 of the cylindrical guide. Then, the cooling air sent from the refrigerant feeding means 110 is circulated around the strands 50 that respectively pass through the insides of the plurality of cylindrical guides 60, and each of the plurality of strands 50 is allowed to pass within a short time. It is better to cool and solidify at the same time. The solidified strand 50 discharged from the lower end opening 64 of the cylindrical guide to the lower side of the cylindrical guide 60 is preferably cut into a certain length sequentially by a cutter 90 and formed into a pellet. And it is good to be able to form many pellets simultaneously and efficiently in a short time.
Further, the molten plastic extruded from the extrusion means 10 is formed by diverging into a plurality of strands 50 by a die, and the plurality of strands 50 are separately passed through the plurality of cylindrical guides 60, respectively. It is preferable to improve the efficiency of cooling the strands 50 in the molten state passing through the insides of the plurality of cylindrical guides 60 by the air cooling type cooling means 100. Then, it is preferable that the plurality of strands 50 cooled and solidified for pellet formation can be simultaneously and efficiently formed in a short time.

In this pellet forming apparatus, the air-cooling refrigerant sent to the inside of the cylindrical guide 60 by the refrigerant feeding means 110 may be cooling air cooled to minus temperature or the like instead of air at normal temperature.
And the cooling efficiency by the cooling means 100 of the strand 50 which is passing the inside of the cylindrical guide 60 may be reliably greatly improved by the cooling air which is the refrigerant for air cooling. At the same time, the strand 50 passing through the inside of the cylindrical guide 60 may be stably and surely cooled and solidified by the cooling means 100 without being affected by changes in the atmospheric temperature.
In this case, for example, an ultra-low temperature air generator called a vortex tube that cools the air sent from the compressor to an ultra-low temperature state may be used as the refrigerant feeding means 110.

In this plastic pellet forming apparatus, as shown in FIG. 1, a squeezing nozzle 120 for forming a strand whose tip inner diameter is smaller than the inner diameter of the cylindrical guide 60 is disposed at the lower end 46 of the strand forming path of the die. It is preferable to have a structure that is provided in communication with each other. The tip of the throttle nozzle 120 may be structured so as to be introduced inside the upper end opening 62 of the cylindrical guide in a suspended state in contact with the inner wall of the cylindrical guide 60.
And the strand 50 in the molten state extruded from the die 40 is passed through the inside of the strand forming squeezing nozzle 120 provided at the lower end 46 of the strand forming path, and the outer diameter of the strand 50 is changed to the cylindrical guide 60. It is good to narrow down to a small diameter down to the inner diameter of the tip of the stop nozzle 120 having a smaller diameter than the inner diameter of the nozzle. The strand 50 narrowed down to the small diameter may be smoothly introduced into the cylindrical guide 60 having an inner diameter larger than that of the strand 50 without being caught from the upper end opening 62.
At the same time, the squeezing nozzle 120 in which the melted strand 50 having an adhesive force pushed out from the die 40 is introduced inside the upper end opening 62 of the cylindrical guide in a suspended state in contact with the inner wall of the cylindrical guide 60. It is preferable that the front end of the cylindrical guide 60 is not attached to the inner wall of the cylindrical guide 60, and it can be smoothly introduced without being caught by being caught in the center of the cylindrical guide 60.
The air-cooling refrigerant is a gap between the refrigerant feeding means 110 and the inner wall of the upper end opening 62 of the cylindrical guide and the outer wall of the distal end of the throttle nozzle 120 introduced in a suspended state inside the upper end opening of the cylindrical guide. It is preferable to use a structure in which it is fed into the cylindrical guide 60 through the inside.

  In this pellet forming apparatus, the inner diameter of the cylindrical guide 60 is 1.5 to 3.0 times the inner diameter of the tip of the squeezing nozzle 120 based on the results of pellet formation experiments using various plastic materials of different types and different colors. It was found that it is preferable that the ratio is 2.0 times.

  In this pellet forming apparatus, as shown in FIG. 3, it is also possible to use the aforementioned hot rotating screw as the molten plastic extrusion means 10.

  The pellet forming apparatus of the present invention can be widely used for placing various types of pellets of different types and different colors efficiently without taking time in a plastic forming site having a small installation area.

It is front sectional drawing of the plastic pellet formation apparatus of this invention. It is a bottom view of the location with which the cutter of the plastic pellet forming apparatus of this invention was equipped. It is front sectional drawing of the other plastic pellet formation apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Extruding means 12 Rotating body 14 Spiral groove | channel 16 Electric motor 18 with a reduction gear 18 Hopper 20 Plastic material 30 Electric heater 32 Heating cylinder 40 Die 44 Strand formation path 46 Strand formation path lower end 50 Strand 60 Cylindrical guide 62 Cylindrical guide Upper end opening 64 Lower end opening 70 of cylindrical guide Device frame 72 Device frame upper end 76 Refrigerant passage 80 Heat insulating plate 90 Cutter 92 Fixed blade 94 Rotary blade 96 Transmission electric motor 100 Strand cooling means 110 Refrigerant feeding means 112 Refrigerant introduction path 120 nozzles

Claims (5)

Extruding means for molten plastic that melts and extrudes the plastic material for pellet formation,
A molten plastic extruded from the extrusion means is introduced into a strand forming path to form a strand, and a die for extruding the strand vertically downward from the lower end of the strand forming path;
A cylindrical guide erected perpendicularly directly below the lower end of the strand forming path of the die, and the strand pushed out of the die is introduced from the upper end opening portion thereof, passed through the inner side thereof, and then opened at the lower end thereof. A cylindrical guide discharged from the section,
With a strand cutting cutter that sequentially cuts the strand discharged from the lower end opening of the cylindrical guide into a certain length,
The strand cooling means sends air-cooling refrigerant to the inside of the cylindrical guide from the upper end opening of the cylindrical guide so as not to leak into the outside air, and passes through the inside of the cylindrical guide. A plastic pellet forming apparatus characterized in that after circulating around the strand, the plastic guide is discharged from the lower end opening of the cylindrical guide to the outside of the cylindrical guide. The die divides and introduces the molten plastic extruded from the extrusion means into a plurality of strand formation paths, and extrudes the strands vertically downward from the lower ends of the plurality of strand formation paths connected to the plurality of strand formation paths. Is,
The cylindrical guides are a plurality of cylindrical guides that vertically stand directly below the lower ends of the plurality of strand forming paths, and the strands extruded vertically downward from the lower ends of the strand forming paths are 2. The plastic pellet forming apparatus according to claim 1, comprising a plurality of cylindrical guides that are introduced and allowed to pass through the inside of the cylindrical guide and then discharged from the lower end opening to the outside of the cylindrical guide.   The plastic pellet forming apparatus according to claim 1, wherein the air cooling refrigerant is cooling air.   2. The plastic pellet forming apparatus according to claim 1, wherein the air cooling refrigerant is room temperature air.   At the lower end of the strand forming path of the die, a throttle nozzle for forming a strand having a tip inner diameter smaller than the inner diameter of the cylindrical guide is provided in communication with the strand forming path, and the tip of the throttle nozzle is the cylindrical guide. 2. The plastic pellet forming apparatus according to claim 1, wherein the plastic pellet forming apparatus is introduced into the inner side of the upper end opening portion in a suspended state without contact with the inner wall of the cylindrical guide.

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