JPH0986592A - Hopper tank for extrusion molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent fluctuation of extrusion to be caused by uneven distribution of ground product and powder in a mixed raw material and fluctuation of extrusion caused by fluctuation of temp. of the raw material from occurring by providing an agitator by which the raw material can be stirred in a raw material storing room and a cooler in the storing room and a screw room. SOLUTION: In a hopper tank provided with a tank main body 10 with a storing room 11 in which a feeding hole and a discharging hole are respectively opened on the upper part and the lower part and a screw case 30 with an extrusion screw below it, an agitator 20 by which the raw material can be stirred in the lower part of the storing room 11 of the tank main body 10. In addition, the screw case 30 is formed by a double shell structure with a water jacket and a jacket member 14 is provided on the lower half part of the tank main body 10 to form a water jacket. In addition, the extrusion screw in the screw case 30 is constituted in a hollow structure with a cooling path and a cooling medium is circulated therein to cool it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hopper tank for storing a raw material mixed with powder or pulverized material and supplying it to an extruder or the like when extrusion-molding a film or the like. The present invention relates to a hopper tank that can be held and continuously supplied at a uniform density.

[0002]

2. Description of the Related Art When a film or the like is extruded, a raw material mixed with powder or pulverized material is cooled by a cooling mixer and sent to a hopper tank by air transportation, and the raw material is temporarily stored in the hopper tank. The raw material is continuously supplied from the tank to the extruder. Conventionally, as a hopper tank for an extruder used for such extrusion molding, a screw case is fixed to the lower part of the tank body,
It is known that the raw material charged into the charging port in the upper part of the tank body is dropped into the screw case by its own weight and continuously supplied to the extruder by the extrusion screw in the screw case.

[0003]

However, in the above-mentioned conventional hopper tank for an extruder, the raw material is separated into powder and pulverized product due to the difference in bulk specific gravity during pneumatic transportation. Since the raw material is fed in a state, the powder or pulverized material is agglomerated and unevenly distributed in the raw material supplied to the extruder by the screw, which causes a problem of extrusion fluctuation which causes a defective product. Further, in such a hopper tank, there is a problem that the bite of the raw material into the extrusion screw is influenced by the temperature of the stored raw material, and the amount of the bite into the extrusion screw varies to cause extrusion fluctuation.

Particularly, the latter problem is remarkable because the raw material is strongly influenced by the outside air temperature during pneumatic transportation, and the raw material temperature greatly changes due to temperature changes in the four seasons such as summer and winter, and daily temperature changes. Met. The present invention has been made in view of the above problems, and is a hopper tank that can prevent extrusion fluctuation due to uneven distribution of pulverized material or powder in a mixed raw material, and extrusion fluctuation due to fluctuation of raw material temperature. Provide
The purpose is to eliminate problems caused by pneumatic transportation of raw materials.

[0005]

In order to achieve the above object, the present invention provides a tank main body which defines a raw material storage chamber having an input port at an upper part and an outlet port at a lower part, and a lower part of the tank main body. In a hopper tank for an extruder equipped with a screw case that defines a screw chamber in which the discharge port is opened, and an extrusion screw rotatably provided in the screw chamber, raw material storage of the tank body An agitator provided inside the chamber to stir the raw material, and a cooler capable of cooling the raw material in the storage chamber and the screw chamber are provided, and the extrusion screw is configured to have a hollow structure having a cooling passage, and the cooling is performed. Refrigerant was returned to the passage to cool the extrusion screw.

According to the present invention, the agitator is
The rotating shaft and a plurality of stirring pieces which are radially separated from the rotating shaft and spirally extend in a range of less than 360 degrees around the rotating shaft, and the stirring pieces are symmetrical with respect to the rotating shaft. It can be configured in such a manner that it is attached to (Claim 2).

[0007]

According to the hopper tank for the extruder according to the present invention, the raw material charged into the raw material storage chamber through the charging port is agitated by the agitator and dropped into the screw chamber by its own weight and cooled by the cooler in the screw chamber. Is
It is supplied to an extruder by an extrusion screw. Therefore, even if the powder or pulverized raw material is unevenly distributed due to air transportation, etc., or if the raw material temperature fluctuates depending on the time of the day or the season due to the influence of the outside air temperature, etc., it is possible to prevent extrusion fluctuation. it can.

In the hopper tank for an extruder according to the second aspect of the present invention, the agitator is symmetrical with respect to the agitating piece in which the agitator extends in a partial spiral shape while being radially separated from the rotating shaft. ° It is configured so as to be fixed so as to be separated from each other, and the stirring piece stirs so that the raw material near the bottom of the raw material storage chamber mixes with the raw material in the central part, so that uneven distribution of pulverized material or powder can be more effectively prevented. , High cooling efficiency is achieved. That is, the powder and pulverized material are unevenly distributed near the bottom surface of the raw material storage chamber due to the bulk specific gravity, the raw material near this wall surface is cooled by the cooler, and the agitator effectively stirs and mixes the cooled and unevenly distributed crushed material. can do.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 show a hopper tank for an extruder according to an embodiment of the present invention, FIG. 1 is a front view, FIG. 2 is a plan view, FIG. 3 is a side view, and FIG.
Is an enlarged partial sectional view of a part, FIG. 5 is an enlarged view of main parts, and FIG. 6 is a sectional view of main parts.

In FIGS. 1, 2 and 3, 10 is a tank body of a substantially rectangular parallelepiped shape that defines a storage chamber 11 inside, and the tank body 10 has an inlet (not shown) at the upper portion and one end at the lower portion (see FIG. 1, a discharge port (not shown) is formed on the left side.
The tank main body 10 is provided with a lid 13 that can open and close a charging port on the upper portion, and a screw case 30 is fixed on the lower portion. The lid 13 is made up of two rectangular flat plate-like lid pieces 13a, 13
a is connected by a hinge 13b, and one lid piece 13 is formed.
The handle 13c is fixed to the surface of a. Although not shown, in this tank body 10, a raw material in which powder and pulverized material are mixed is charged into the storage chamber 11 from the charging port by pneumatic transportation.

The tank body 10 is covered with a jacket member 14 at a substantially half portion of the lower outer surface of the tank body 10 at predetermined intervals.
A water jacket (cooler) 15 is defined between the lower half of the outer surface and the jacket member 14. The jacket member 14 is provided with a cooling water supply joint 16 at the lower part of one side and a cooling water discharge joint 17 at the upper part of the other side.
17 is connected to the cooling water supply source by a hose or the like not shown. In the water jacket 15, the cooling water (industrial water, etc.) supplied from the cooling water supply source flows back through the joint,
The tank body 10, that is,
The raw material in the lower part of the storage chamber 11 of the tank body 10 is cooled.
Reference numeral 18 is a drain plug that closes a drain hole formed at one end of the bottom of the jacket member 14.

Further, the tank body 10 has a storage chamber 11
Pillow block unit 2 with agitator 20 at the bottom inside
The motor 22 for driving the agitator is attached to one end of the jacket member 14 by the base member 21. The pillow block units 28 and 29 are attached to the tank body 10 and the jacket member 14 so as to penetrate the water jacket 15, and the pillow block unit 28 includes the sprocket 2
8a rotatably supports the fixed drive shaft, and the pillow block unit 29 rotatably supports the driven shaft. The sprocket 22a of the motor 22 is attached to the sprocket 28a.
A chain 25 is hung between and.

In the agitator 20, as shown in detail in FIGS. 5A, 5B and 5C, two stirring pieces 24, 24 are fixed to a rotary shaft 23 symmetrically around the rotary shaft 23, that is, 180 ° apart. The flanges 23a, 23a are fixed to both ends of the rotary shaft 23, respectively. This rotary shaft 23
The flanges 23a and 23a are pillow block units 28.
Is coupled to the driven shaft of the pillow block unit 29 by a bolt or the like, and is driven by the motor 22.
The stirring piece 24 is made of a rod or a pipe-shaped member, and extends spirally around the rotary shaft 23 over a range of about 180 °. The stirring piece 24 has a middle portion and a rear end in the rotation direction R fixed to the rotation shaft 23 by a spoke member 26.
The agitator 20 is configured such that the ratio of the area of the stirring piece 24 to the cross-sectional area of the storage chamber 11 is 0.1 to 0.3, and the distance between the stirring piece 24 and the wall surface of the storage chamber 11 is 5 to 20 mm.
It is desirable to arrange so as to form a space of 4 and to drive at a rotation speed of 5 to 30 rpm.

Reference numeral 71a is an upper limit level meter, 71b is a lower limit level meter, and 72 is a viewing window for visually observing dirt and the like in the water jacket 15. The upper limit level meter 71a is provided at an upper portion of the tank body 10 (preferably at a position 0.8 to 1.2 times the diameter of the agitator 20 from the bottom of the storage chamber 11) and the storage chamber at that height is provided. The presence or absence of the raw material in 11 is detected, and similarly, the lower limit level meter 71b is provided below the upper limit level meter 71a to detect the presence or absence of the raw material at the height. These level meters 71
The a and 71b are connected to a controller (not shown), and the controller drives an air transportation device or the like to control the supply of the raw material into the storage chamber 11. As an example of this control, when the upper limit level meter 71a detects the raw material for a certain period of time, the raw material transportation is stopped, and when the upper limit level meter 71a does not detect the raw material for the certain period of time, the raw material transportation is restarted.

Although not shown in the drawing, the screw case 30 has a double shell structure in which at least a part of the inner shell and the outer shell are joined, and the supply cylinder 39 is extruded at the lower part of one side, which is not shown. A motor 40 for driving an extrusion screw, which will be described later, is provided on the upper side of one side. The supply tube 39 has an open end connected to a pipe and is connected to the extruder through the pipe. The screw case 30 defines a water jacket (cooler) between the inner shell and the outer shell, and defines a screw chamber 31 between the screw case 30 and the tank body 10. This screw case 30 has a cooling water supply joint 32 on one end side.
A cooling water discharge joint 33 is provided at the other end, and a drain plug 34 for closing the water drain hole is provided at the bottom. These joints 3
2, 33 are connected to a cooling water supply source (not shown) via a hose or the like, and the cooling water flows back to the water jacket via these joints 32, 33.

In this embodiment, the water jacket 15 or the like is illustrated as the cooler provided in the tank body 10 and the screw case 30, but a heat pump type heat exchanger or the like can be used as the cooler. . In addition, in this embodiment, the tank body 10
Although both the screw case 30 and the screw case 30 are cooled, the present invention can also be achieved by cooling only the portion for feeding the raw material to the extruder, that is, the screw case 30.

An extrusion screw 35 is rotatably housed inside the screw chamber 31.
The discharge port described above is opened on one side in the extending direction and communicates with the storage chamber 11, and the supply cylinder 39 is provided on the other side in the extending direction of the extrusion screw 35.
Opens. As shown in detail in FIG.
5, the spiral protrusion 35a is formed on the outer peripheral surface, and
It has a hollow structure in which a water guiding pipe 36 is coaxially inserted, and is partitioned by the water guiding pipe 36 to define an outgoing passage 36a and a returning passage 36b of the cooling water.

Both ends of the extrusion screw 35 are rotatably supported by the screw case 30 by pillow block units 37, and the forward path 36a and the return path 3 are provided at one end.
A hose 38 (only one of which is shown) communicating with 6b is connected via a rotary joint 64, and a sprocket 41 is fixedly installed at the other end. The hose 38 is connected to a cooling water supply source (not shown) so that the cooling water can flow back through the forward path 36a and the return path 36b, and the sprocket 41 is connected to the sprocket 40a provided on the rotation shaft of the motor 40 by a chain 42. To be dressed.

In the hopper tank according to this embodiment, a raw material mixed with powder or pulverized material is transported by pneumatic transportation and is charged into the storage chamber 11 through the charging port, and the raw material is stored in the storage chamber 11. Then, the raw material in the storage chamber 11 is agitated by the agitator 20 and drops from the discharge port into the screw chamber 31 by its own weight, is extruded by the extrusion screw 35 in the screw chamber 31 and is supplied to an extrusion molding machine (not shown). It

Here, the raw material is affected by the outside air temperature when pneumatically transported, and the higher the outside air temperature, the higher the raw material temperature, and the lower the outside air temperature, the lower the raw material temperature. That is, the raw material temperature becomes higher during the day than in the morning or evening,
In addition, the raw material temperature becomes higher in the summer than in the winter, and the temperature fluctuation of the raw material affects the bite of the raw material into the extrusion screw 35 to cause the extrusion variation. However, in this hopper tank, by circulating cooling water to the water jacket 15 of the tank body 10, the lower part of the tank body 10, that is, the raw material in the lower part of the storage chamber 11, is cooled, and in the screw chamber 31. The raw material is also cooled when it is extruded by the extrusion screw 35. Therefore, the raw material temperature can be made constant regardless of the outside air temperature, and extrusion fluctuation can be suppressed.

Further, since the raw materials have different bulk specific gravities from the powder and the pulverized product, the mixed state in which the powder and the pulverized product are uniformly dispersed is destroyed during air transportation, and the powder and the pulverized product are unevenly distributed. This uneven distribution causes extrusion fluctuation. However,
In the hopper tank according to this embodiment, the raw material is stirred by the agitator 20 in the storage chamber 11, and the raw material is uniformly mixed with the powder and the pulverized material, so that the extrusion fluctuation can be suppressed. In particular, the hopper tank of this embodiment is
The agitator 20 has a stirring bar 24 of a spiral rod member,
By this stirring piece 24, the raw material near the inner wall surface of the storage chamber 11,
That is, since the raw material in the portion that tends to be unevenly distributed is stirred, it is possible to more effectively prevent uneven distribution of the pulverized material of the raw material and the like.
Further, since the raw material near the inner wall surface of the storage chamber 11 is cooled by the water jacket 15, high cooling efficiency can be obtained.

[0022]

As described above, according to the hopper tank for an extruder according to the present invention, the raw material charged into the raw material storage chamber through the charging port is cooled by the cooler and by the agitator. The mixture is stirred and falls into the screw chamber by its own weight, is cooled again by the cooler in the screw chamber, is extruded by the extrusion screw cooled by the cooling water, and is supplied toward the extruder. Therefore, even if the powder or pulverized raw material is unevenly distributed due to air transportation, etc., or if the raw material temperature fluctuates depending on the time of the day or the season due to the influence of the outside air temperature, etc., it is possible to prevent extrusion fluctuation. it can.

According to the hopper tank for the extruder according to the second aspect of the present invention, the agitator is formed by symmetrically fixing the partially spiral agitating pieces on the rotating shaft in the radial direction with a space therebetween. Since the agitator mainly stirs the cooled raw material near the bottom of the raw material storage chamber so that it mixes with the central raw material, the raw material can be effectively cooled and maintained at a constant temperature. Uneven distribution can be more effectively prevented, and extrusion fluctuation can be prevented or suppressed. That is, the powder is unevenly distributed in the vicinity of the bottom surface of the raw material storage chamber due to the bulk specific gravity, and the pulverized product is unevenly distributed in the upper part because the bulk specific gravity is small, but the unevenly distributed pulverized product can be effectively stirred and mixed. .

[Brief description of drawings]

FIG. 1 is a front view of a hopper tank for an extruder according to an embodiment of the present invention.

FIG. 2 is a plan view of the hopper tank.

FIG. 3 is a side view of the hopper tank.

FIG. 4 is a partially enlarged cross-sectional view of the same hopper tank.

FIG. 5 shows main parts of the same hopper tank, a is a front view, b is a left side view, and c is a right side view.

FIG. 6 is a sectional view of a main part of the hopper tank.

[Explanation of symbols]

 10 Tank Main Body 11 Storage Chamber 14 Jacket Member 15 Water Jacket (Cooler) 20 Agitator 23 Rotating Shaft 24 Stirring Piece 31 Screw Chamber 35 Extrusion Screw

Claims (2)

[Claims] 1. A tank main body defining a raw material storage chamber having an opening at an upper portion and an outlet opening at a lower portion, and a screw chamber provided at a lower portion of the tank body and having an outlet opening. In a hopper tank for an extruder including a screw case and an extrusion screw rotatably provided in the screw chamber, an agitator capable of stirring the raw material provided in the raw material storage chamber of the tank body, With a cooler capable of cooling the raw materials in the storage chamber and the screw chamber, the extrusion screw is configured to have a hollow structure having a cooling passage, and a refrigerant is circulated in the cooling passage to cool the extrusion screw. Hopper tank for the extruder. 2. The agitator includes a rotating shaft, and a plurality of stirring pieces that are radially separated from the rotating shaft and spirally extend in a range of less than 360 degrees around the rotating shaft. The hopper tank for an extruder according to claim 1, wherein a stirring piece is symmetrically attached to the rotating shaft.