JPH069786Y2 - Pellet-shaped plastic manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to an apparatus for producing pelletized plastic.

<Prior art> Conventionally, in order to cut the high temperature, sticky plastic material discharged from the extruder nozzle into pellets, a cutting device is installed in the water, and at the same time as cutting, the pelletized plastic is rapidly cooled with water, and then the submerged There is a device that floats on the ground and transfers and collects it together with water.

As another conventional device, there is a device in which plastic discharged from a nozzle of an extruder is cut in air, dropped on a steel belt, and the steel belt is cooled from its inner surface with cooling water or the like.

<Problems to be Solved by the Invention> According to the former conventional device, there is a problem that moisture is mixed due to the viscosity when cut, and it is necessary to remove attached moisture after solidification. Further, water-soluble or water-containing plastic has a drawback that the above-mentioned conventional apparatus cannot be used.

According to the latter conventional device, the above-mentioned problems do not occur,
There is a problem that the cooling effect is worse than that of the conventional device described above, the steel belt needs to be considerably long, and the price becomes expensive.

In order to solve the above-mentioned problems of each conventional device, the present inventor has already cut plastic into a predetermined length by a cutter while cooling plastic that is intensively extruded from a nozzle only by blowing air. A simple, compact and inexpensive pellet plastic manufacturing device that can solidify the surface skin of pellets and remove its stickiness, and that is equipped with various mechanisms for cutting, cooling, and collecting that are integrated with an extruder. Is proposed (Japanese Patent Laid-Open No. 58-155915).

By the way, in the pelletized plastic manufacturing apparatus based on Japanese Patent Laid-Open No. 58-155915, the cutter for cutting the plastic discharged from the nozzle rotates along the nozzle array while contacting the surface of the discharge die. There is a problem that the wear is large and the cutter life is short.

The present invention aims to improve JP-A-58-155915, and by efficiently cooling the plastic only by blowing air, the dehydration work of the resulting pellets is unnecessary, and the structure is simple, small and inexpensive. In addition, it is an object of the present invention to provide a pelletized plastic manufacturing apparatus in which there are few consumable parts such as cutters and the maintenance thereof is extremely easy as in the prior art.

<Means for Solving Problems> A structure for achieving the above-mentioned object will be described with reference to FIGS. 1 and 2 which are embodiment drawings. An extruder 1 having nozzles 3 arranged along the upper side, and bearings 22, 2 coaxially with the central axis of the extruder 1.
3, a front end of a cylindrical body supported by 3 spreads in a horn shape, and its end reaches immediately before nozzles 3 ... 3 rows, and a predetermined position in the circumferential direction of the end of the air guide 21. The ventilation groove 26 formed at the end of the air guide tube 21, and a ventilation blocking portion 27 formed near the surface of the discharge die 2 that is substantially impermeable to air, except for the ventilation groove 26 at the end of the air guide tube 21. Wind tube 2
1 rotation driving means (for example, motor) 12 and air guide tube 21
The blower 8 communicating with the rear end opening of the body of the
The punch 2 which is fixed to the outside of the ventilation groove 26 and rotates along the nozzle rows 3 ... 3 with a predetermined gap from the surface of the discharge die 2.
8 and an annular ventilation passage 35 along the trajectory of the punch 28.
And an exhaust pipe 10 communicating with the. Then, the air blown by the blower 8 is discharged through the air guide tube 21 substantially only from the ventilation groove 26, and the plastic discharged from the nozzles 3 ... 3 of the extruder 1 is cooled to a predetermined length by the punch 28. The sheared and pelletized plastic is conveyed to the exhaust pipe 10 while being cooled and solidified by the air blown out from the ventilation groove 26.

<Operation> The present invention is based on the fact that in the device proposed in Japanese Patent Laid-Open No. 58-155915, it was confirmed that the plastic discharged from the nozzle can be cooled very rapidly. That is, the wind blown from the blower 8 via the air guide tube 21 is jetted out from only the air passage groove 26 to the air passage 35 at the end portion of the horn-shaped front end of the air guide tube 21, and the high speed is generated here.・ The pressure becomes low and the temperature is lowered by the adiabatic expansion effect, and the plastic discharged from the nozzles 3 ... 3 is directly hit and rapidly cooled. As a result, the plastic has a predetermined brittleness, and the punch 2 is rotated along the nozzle row 3 ... 3 with a predetermined gap from the surface of the discharge die 2.
It can be sheared by 8, and is not worn due to contact with the discharge die 2, and the initial purpose can be achieved. The pelletized sheared plastic is further cooled in the ventilation passage 35 by the wind from the ventilation groove 26, and the surface thereof is solidified and dried into a dry state, and is introduced into the exhaust gas engine 10.

<Example> An example of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a partially disassembled embodiment of the present invention.

A circular discharge die 2 provided at the tip of the extruder 1 is provided with a large number of nozzles 3 ... 3 along its circumference, and viscous plastic is continuously discharged from these nozzles. . The front surface 5 of the pellet cutting device 4 is disposed almost in close contact with the discharge die 2 of the extruder, and the opening 6 at the rear end of the cutting device 4 is blower through the cooler 13 that cools the air through the duct 7. 8 is connected, and the pelletized product is a cutting device 4
From the pellet product outlet 9 in the front part of the above, it is collected in the silo 11 through the exhaust pipe 10. The motor 12 is for rotating and driving a wind guide tube 21 of the cutting device, which will be described later.

FIG. 2 shows a vertical sectional view of the cutting device 4. The air guide tube 21 for blowing air on the pellets at the time of cutting has a cylindrical body rotatably supported by ball bearings 22 and 23, and has a rotary shaft coaxial with the central axis of the extruder 1. , Is driven to rotate by the motor 12 via a pulley 24 attached to the rear portion. Further, a blower duct 7 is connected to the opening 6 at the rear end of the air guide tube 21, and the front portion of the air guide tube 21 expands in a horn shape so as to face the discharge die 2 of the extruder 1 and its end. 3 reaches just before the nozzle rows 3 ... 3 provided on the circumference of the discharge die 2 to form a flange portion 25. FIG. 3 shows a side view of the end portion of the flange portion 25 extending in the horn shape, which reaches just before the nozzle rows 3 ... 3 from the left direction in FIG. Vent grooves 26 are provided at the ends of the horn-shaped flange portions 25 at positions that divide the circumference into three equal parts,
The end other than the ventilation groove 26 is formed close to the surface of the discharge die 2 to form a ventilation shield portion 27 that substantially shields the blown air.
A punch 28 is attached to each of the above-described three ventilation grooves 26 via a punch attachment member 29.

Each punch 28 is provided with a predetermined gap g (for example, 10 mm) from the surface of the discharge die 2 as shown in FIG. 4 which is an enlarged view of a main part viewed from the outside of the ventilation groove 26 in the direction along the ventilation groove 26. Installed. The diameter of the arrangement pitch circle of the punches 28 is substantially equal to the diameter of the arrangement pitch circle of the nozzles 3 ... 3 of the discharge die 2, and each punch 28 has three rows of nozzles 3 ... Will rotate along. Further, as shown in FIG. 4, the punches 28 and the punch mounting members 29 are mounted in the ventilation groove 26 so that they do not interfere with the discharge of air from the inside, for example, in the direction opposite to the rotational direction. Has been.

Along the trajectory of the punches 28 ... 28, an annular ventilation passage 35 is formed.
Is formed, and this ventilation path 35 is connected to the exhaust pipe 10 via the pellet product outlet 9.

It should be noted that packing is provided between the periphery of the flange portion 25 at the front portion of the air guide tube 21 and the exhaust pipe 35, and between the periphery of the rear end opening 6 of the air guide tube 21 and the duct 7 with packings 36 and 37. It has been stopped.

A conical member 38 is attached to the center of the front surface of the discharge die 2. The conical member 38 is provided so that the air blown through the air guide tube 21 is smoothly guided to the ventilation groove 26.

Next, the operation will be described. The linear plastic having a diameter of 2 to 5 mm discharged from each nozzle 3 ... 3 of the extruder is directly cooled by the wind blown from the blower 8 through the air guide groove 21 through the cooler 13 and the ventilation groove 26 to be rapidly cooled. At the same time, as shown in the explanatory view of its operation in FIG. 5, it collides with the rotating punch 28 and is sheared into pellets of substantially constant length with the front edge of the nozzle 3 as the shearing surface, thus forming an annular shape. Falls into the ventilation passage 35. In the ventilation passage 35, the pellet-shaped plastic is further cooled by the cold air ejected from the ventilation groove 26 and collected in the silo 11 via the exhaust pipe 10.

When the air that has passed through the air guide tube 21 from the blower 8 is ejected from the ventilation groove 26 formed at the horn-shaped front end of the air guide tube 21,
The flow path is once abruptly fitted and expanded again in the air passage 35, so that the speed is increased and the pressure rapidly changes to a low pressure, and the temperature thereof is lowered by the adiabatic expansion effect. And
Since this air is directly hit on the plastic discharged from the extruder 1, its cooling effect is great. In this way
At the beginning, the plastic that was sticky and soft and sticky when discharged from the extruder 1 is collected in the silo 11 in the form of free-flowing pellets.

<Effect of the Invention> As described above, according to the present invention, the plastic continuously discharged from the nozzles 3 ... 3 of the discharge die 2 of the extruder 1 is guided from the blower 8 with its front end spreading like a horn. The air blown through the air duct 21 is directly hit by the air jetted from the ventilation groove 26 to rapidly cool and impart brittleness, and a predetermined gap g is formed between the surface of the discharge die 2 and the nozzle 3. Since it is sheared into pellets by the punch 28 which rotates along the line 3, no abrasion is caused due to contact with the discharge die like the cutter in the conventional device of this kind, and the cutting (shearing) tool It is possible to obtain a pelletized plastic manufacturing apparatus having a dramatically improved life, a low running cost, and extremely easy maintenance. Particularly for engineering plastics with a high melting temperature of 150 to 170 ° C, the plastic discharged from the discharge die is rapidly solidified by the direct hit of air whose temperature is lowered by adiabatic expansion, and the punch is used. It has been confirmed that shearing is easy.

Moreover, since a liquid such as water is not used, dehydration work after solidification is unnecessary, and even water-soluble plastic can be easily pelletized.

[Brief description of drawings]

FIG. 1 is a partially exploded perspective view of an embodiment of the present invention, FIG. 2 is a vertical sectional view of the cutting device 4, FIG. 3 is a side view of the flange portion 25 seen from the left side of FIG. 2, and FIG. FIG. 6 is an enlarged view of a main part as seen from the outside of the ventilation groove 26 in a direction along the ventilation groove 26. FIG. 5 is an explanatory view of the shearing action by the punch 28 of the embodiment of the present invention. 1 ... Extruder, 2 ... Discharge die 3 ... 3 ... Nozzle, 4 ... Cutting device 8 ... Blower, 10 ... Exhaust pipe 12 ... Motor, 21 ... Bladder 26 ... Ventilation groove, 27 ... Ventilation block 28 ... Punch, 35 ... Ventilation path

Claims (1)

[Scope of utility model registration request] 1. An extruder in which nozzles are arranged along the circumference of a discharge die, and a front end of a cylindrical body supported by a bearing coaxial with the central axis of the extruder spreads in a horn shape. An air guide tube whose end reaches immediately before the nozzle row, and a ventilation groove formed at a predetermined position in the circumferential direction of the end portion of the air guide tube,
A ventilation shield formed in a portion other than the ventilation groove forming portion at the end portion of the air guide tube, which is close to the surface of the discharge die and is substantially impermeable to air; a rotation driving means for the air guide tube; And a punch that is fixed to the outside of the ventilation groove of the air guide tube and that rotates along the nozzle row with a predetermined gap from the surface of the discharge die, and the punch. And an exhaust pipe communicating with an annular ventilation path along the locus of, the air blown by the blower discharges substantially only from the ventilation groove through the air guide pipe, and continuously from the nozzle of the extruder. It is configured such that the plastic expelled into the pipe is cooled while being sheared to a predetermined length by the punch, and the sheared pellet-shaped plastic is cooled and solidified by the air blown out from the ventilation groove to the exhaust pipe. Pele Apparatus for manufacturing a door-like plastic.