JPH07102573B2 - Cooling method for pellet strands - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to a method for cooling strands for extruded pellets.

[0002]

2. Description of the Related Art In a pellet manufacturing method generally called a strand cut method, an extruded strand is cut into pellets of a certain length. However, the strand is cooled and solidified by a guide roller near the bottom. The water tank provided with is disposed below the nozzle of the extruder. The cooled strand is wound on a roll after removing water droplets attached to the surface by a water draining device.

[0003]

In the conventional method using the water tank, since the extruded molten strands are cooled by passing them through water, a large water tank having a deep water and a large amount of cooling water are required. Since the cooling of water is limited to the water directly under the nozzle, the cooling efficiency was poor despite the large amount of cooling water required.

The present invention was conceived in order to solve the problem of cooling by the conventional water tank, and an object thereof is to adopt a cooling device having a cooling nozzle in the middle of a conduction path provided inside. Another object of the present invention is to provide a cooling method capable of cooling a strand extruded with a cooling fluid such as cooling water or cold air more efficiently than in the case of using a water tank.

[0005]

According to the present invention according to the above object, there is provided a main body having a concave cross section, a cooling fluid supply port provided at a side portion thereof, and a lower conduction passage having a funnel-shaped inner opening in the center thereof. And a screwing member in the upper part of the main body having a tapered core with an upper conduction path opened in the center of the inside, a cooling device in which an annular cooling nozzle is formed downward at the boundary between the lower conduction path and the upper conduction path of the extruder. It is arranged vertically below the nozzle, and the extruded strand is introduced into the conduction path of the cooling device, and the cooling fluid is blown from the cooling nozzle to the lower conduction path to cool the strand.

Air, water, an inert gas, or the like is used as the cooling fluid. If necessary, a plurality of the above cooling devices may be arranged in upper and lower two stages, or between the nozzle of the extruder and the cooling device, a water tank provided with a conduit for the strand at the center of the bottom may be arranged. After the strands are primarily cooled by the cooling water in the water tank, the strands are introduced together with the cooling water into the cooling device, and the cooling water is blown out from the cooling nozzle inside to perform the secondary cooling of the strands.

The conduction passage formed by the lower conduction passage and the upper conduction passage in the cooling device can be formed long by extending the pipe passage in the lower conduction passage, and the inner diameter is somewhat different between the lower portion and the upper portion. However, the strand is formed to be significantly larger than the outer diameter of the strand, and the strand receives cooling while moving along with the cooling fluid in the conduction path.

Further, for the purpose of improving the cooling efficiency, the pipe extending to the lower conducting passage is cooled from the outside to maintain the temperature of the cooling fluid around the strand flowing down in the strand pipe and improve the cooling efficiency. You can also

[0009]

[Operation] In such a cooling method, the position of the strand is kept at the center of the conduction path by the cooling fluid blown from the annular cooling nozzle toward the center of the lower conduction path, and the strand is kept on the wall surface of the conduction path. Move without touching. Further, the cooling fluid flowing in the moving direction of the strand keeps the strand in the cooling atmosphere for a long time, and as a result, the cooling distance is shorter and the amount of the cooling fluid used is smaller than that in the case of using the water tank.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 denotes a main body having a concave cross-section, a cooling fluid supply port 2 is provided at a side portion thereof, and a lower conduction path 5 having an inner opening 3 expanded in a funnel shape is provided at the center of the lower portion. Further, the inside of the main body 1 is formed in a cooling fluid adjusting chamber 8 by a member 7 screwed with a screw 4 inside the opening edge 6.

At the center of the inner side of the screw member 7, a truncated cone-shaped tapered core 10 having an upper conducting path 9 is provided. The side surface angle of the tapered core 10 is
The inner opening 3 is formed with an inclination angle of 10 ° to 25 °, and is designed to fit within the above-mentioned inner opening 3 formed in the range of 2 ° to 5 ° or more than the inclination angle with a required inclination gap 11 left therebetween. ing.

Further, the inner diameter R1 of the lower conduction path 5 and the inner diameter R2 of the upper conduction path 9 are formed in the relationship of R1 ≥R2 in consideration of the flow resistance of the cooling fluid in the lower conduction path 5. Both of them are formed to be significantly larger than the outer diameter of the strand (for example, R1: 10 to 5 mm).

The adjusting chamber 8 and the inclined gap 11 in the main body communicate with each other, and at the boundary between the lower conduction path 5 and the upper conduction path 9, an annular surface formed by the inclined surface of the inner opening 3 and the edge of the tapered core 10. The cooling nozzle 12 is formed downward, so that a cooling device 13 such as a cooling fluid such as air or water from the supply port 2 that passes through the adjusting chamber 8 and is annularly blown to the lower conduction path 5 is configured. . The cooling nozzle 12
The opening can be arbitrarily adjusted by rotating the screwing member.

In the cooling device 13 of FIG. 1, the lower conduction path 5 is formed downwardly by a pipe 14 extending to the lower surface of the main body, and an outlet 15 and an inlet 16 are vertically arranged around the pipe 14. The cooling jacket 17 is provided to maintain the temperature of the cooling fluid flowing down the lower conduction path 5 and enhance the cooling efficiency. Reference numeral 18 denotes a conduit connected to the lower conducting path 5.

Such a cooling device 13 is vertically installed directly below a nozzle 19 of an extruder (not shown), and a supply pipe of an air supply device having a pump and a flow rate controller at a supply port 2. Roads (not shown) are connected. A cooling water circulation pipe is connected to the outlet 15 and the inlet 16 of the cooling jacket 17, and the nozzle 14 is cooled while cooling the pipe body 14 with the cooling water supplied to the cooling jacket 17 to maintain the temperature of the cooling fluid. The molten strand 20 extruded from 19 can be cooled.

Air is used as a cooling fluid for the strands 20, and the amount of air blown out from the cooling nozzle 12 is
It is adjusted in advance so that turbulent flow, eddy current, etc. do not occur in the conducting passage near the cooling nozzle. The strand 20 introduced into the upper conducting path 9 in a molten state from the nozzle 19 is kept in the center of the conducting path by the air blown from the annular cooling nozzle 12 toward the center of the lower conducting path 5, and is cooled. The air flowing downward while being received moves without coming into contact with the wall surface of the conduction path. As a result, the strand 20 is cooled at the same speed as the extrusion molding speed without being hindered from moving due to contact with the wall surface, and the cooling atmosphere is maintained longer by the pipeline, so that the cooling efficiency is also improved. .

In the embodiment of FIG. 2, two cooling devices 13A,
13B are arranged above and below to cool the strand 20 by dividing it into primary and secondary strands. At this time, the cooling device 13
The amount of air blown out can be adjusted for each of A and 13B, and after cooling to the extent that a skin layer is formed on the strand surface by the upper cooling device 13A, the blowing amount of the lower cooling device 13B is made larger than that of the upper strand. Cooling the inside,
This can further increase the cooling efficiency.

In any of the above-mentioned embodiments, when air is used as the cooling fluid, the air used for cooling is discharged from the pipe 18 to the atmosphere except that the air needs to be cooled by a heat exchanger or the like. Is released to. See also Strand 2
It is possible to lengthen the cooling passage by forming the pipe 18 in a curved or spiral shape to the extent that the movement of 0 is not impaired.

FIG. 3 shows a case where water is used as the cooling fluid, and a water tank for primary cooling is provided between the nozzle 19 of the extruder and the cooling device 13 and has a conduction path 21 for the strand 20 in a mound 22 at the bottom center. 23 is provided, while the cooling device 1 is provided.
A guide tube 2 provided with 3 in the water tank 24 and connected to the conduction path 21.
The lower end of 5 is positioned on the upper conducting path 9 of the screw member 7, and the strand 20 from the nozzle 19 is primarily cooled by the cooling water in the upper water tank 23, and then the strand 20
Is introduced into the cooling device 13 together with the cooling water, and the cooling water is blown out from the cooling nozzle 12 to secondarily cool the strand 20.

In this case, the nozzle 19 and the mound 22
It is preferable to be able to adjust the distance L from the cooling water. Since the cooling fluid is cooling water, the cooling jacket 17 shown in FIG. 1 can be omitted. Furthermore, for the strand 20 that has been primarily cooled, the cooling nozzle 12
Since the cooling water is blown downward from the strand, the strand 20 is pulled in the moving direction by the water pressure generated there, and the movement in the cooling device 13 becomes smooth,
Even if the cooling fluid is cooling water, cooling can be continuously performed at a speed commensurate with the extrusion molding speed of the strand 20.

According to the present invention, as described above, the cooling device in which the annular cooling nozzle is formed downward at the boundary between the lower conduction path and the upper conduction path is vertically arranged below the nozzle of the extruder, and inside the cooling device. Since the extruded strands are introduced into and the strands are cooled by the cooling fluid from the cooling nozzle, the amount of cooling fluid used is smaller than when the strands are introduced into water for cooling. Since the cooling fluid blown out from the nozzle is forcibly cooled, the cooling efficiency is improved as compared with the case of passing through water.

Further, since the cooling fluid is applied to the circumference of the strand at the same time and evenly by the annular cooling nozzle, the displacement of the strand is prevented and the blowout amount is moderate even in the case of cooling in the conducting passage having a limited cross-sectional area. Since it can be adjusted, the strand can be continuously cooled at a rate according to the extrusion rate.

Further, since the cooling device is also small in size, even if the cooling device is provided for each nozzle of the extruder, the scale does not become large, and it is a special case when air is used as the cooling fluid. It is not necessary to collect the air except for, and the amount of water used can be small when cold water is used, so the water tank can be small and the cooling efficiency can be further improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of an embodiment of an apparatus used in a method for cooling pellet strands according to the present invention.

FIG. 2 is an explanatory diagram of a cooling method using a plurality of the cooling devices of FIG.

FIG. 3 is an explanatory diagram of a cooling method in which primary cooling means is arranged in front of the cooling device shown in FIG.

[Explanation of symbols]

 1 main body 2 supply port 3 inner opening 4 screw 5 lower conduction path 6 opening edge 7 screwing member 8 adjustment chamber 9 upper conduction path 10 taper core 11 inclined gap 12 annular cooling nozzle 13 cooling device 14 pipe body 17 cooling jacket 18 pipe Channel 19 Extruder nozzle 20 Strand 21 Conducting channel 22 Mound 23 Water tank 24 Water tank 25 Guide tube

Claims (3)

[Claims] 1. A body having a concave cross-section, a cooling fluid supply port on its side, a lower conduction path in the center of which an inner opening is expanded in a funnel shape, and a tapered core having an upper conduction path opened. By the screwing member in the upper part of the main body at the inner center, a cooling device in which an annular cooling nozzle is formed downward at the boundary between the lower conduction path and the upper conduction path is vertically arranged below the nozzle of the extruder,
A method for cooling a strand for pellets, characterized in that an extruded strand is introduced into the passage of the cooling device, and a cooling fluid is blown from the cooling nozzle to the lower passage to cool the strand. 2. The method for cooling a strand for pellets according to claim 1, wherein the cooling fluid is air, water, an inert gas or the like. 3. A strand of water is provided between the nozzle of the extruder and the cooling device, and a conduit for the strand is provided at the center of the bottom, and the strand of water is temporarily cooled by the cooling water in the strand of the strand. 2. The method for cooling pellet strands according to claim 1, wherein the cooling water is introduced into the cooling device together with the cooling water, and the cooling water is blown out from the cooling nozzle to the conducting path of the cooling device to perform secondary cooling of the strand.