JP3484761B2 - Apparatus and method for separating and removing fine particles of polymer pellets - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a separation / removal method capable of continuously separating and removing fine powder particles from polymer pellets.

[0002]

2. Description of the Related Art Usually, polymer pellets are extruded from a polymerization tank or extruder through a slit-shaped or circular die hole having a diameter of 5 to 8 mm, and the belt-shaped or strand-shaped polymer is cooled and solidified and then cut. 1.5 ~
It is pelletized into a 4 mm columnar or prismatic shape and used for fiber and resin molding.

However, in the cutting process for pelletizing the polymer and in the process of transporting the pellets, fine powdery particles are generated, and the fine powdery particles deteriorate the quality of the fiber or resin molded product, It becomes a factor that hinders productivity. Therefore, it is generally practiced to separate and remove fine powder particles having a diameter of less than 1 mm mixed in the polymer pellets. As the separation and removal device for the fine powder particles, there are generally two types, a device provided with a special fixed collision part in a separation tank having a constant space, and a device in which the collision part is rotated by power. Known to be.

These apparatuses supply the polymer pellets from above or below into the separation tank together with the gas for conveying the polymer pellets, and collide the pellets with a special collision portion to separate and remove fine powder particles.

[0005]

However, in these conventional devices, since the special collision portion is provided in the separation tank, the space volume in the separation tank becomes large, so that the pellets can be supplied into the separation tank. Separated fine particles cannot be efficiently discharged to a separate discharge hole from the pellets only with the carrier gas, so the fine particles are separated from the carrier gas for supplying the pellets into the separation tank. It is necessary to supply a dedicated gas for exhausting the body into the separation tank.

Therefore, the object of the present invention is to develop a continuous separation / removal device capable of separating / removing fine powder particles mixed in polymer pellets without providing a special collision part and by only the carrier gas of the pellets. As a result of intensive studies, the present invention has been accomplished.

[0007]

Fine powder or granular material removing device of polymer pellets of the present invention SUMMARY OF THE INVENTION comprises a tubular conical hopper lower portion forms a cone-shaped or pyramidal shape, the hopper from the hopper above A supply pipe inserted therein, and a discharge pipe at the bottom of the hopper,
It is characterized in being composed of an exhaust pipe provided in the side wall portion of the hopper upper part.

Further, the polymer fine powder or granular material separating and removing method of the pellets of the present invention is inserted from above of the tubular conical hopper lower portion forms a cone-shaped or pyramidal shape in said hopper By feeding the polymer pellets containing fine particles together with the carrier gas from the supply pipe, the pellets are discharged from the discharge pipe at the bottom of the hopper, and the pellets are provided on the side wall of the upper part of the hopper.
The fine powder is discharged from the exhaust pipe together with the carrier gas.

An apparatus and method according to an embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a partially cutaway perspective view of a device for separating and removing fine particles. The fine powder and granular material separating and removing apparatus A comprises a cylindrical conical hopper 3 having a cylindrical cylindrical portion 1 on the upper side and a conical portion 2 on the lower side, and a supply pipe inserted into the hopper 3 from the top of the hopper 3. 4, a discharge pipe 5 opening to the bottom of the hopper 3, and an exhaust pipe 6 provided on the upper side wall of the hopper 3. The polymer pellets containing fine particles are supplied to the cylindrical conical hopper 3 through the supply pipe 4 together with the carrier gas, and the pellets discharged from the tip opening of the supply pipe 4 inside the hopper diffuse with the carrier gas. The diffused pellets collide with the conical portion 2, the pellets are separated from the fine particles by the collision, the pellets are taken out from the discharge pipe 5, and the fine particles are discharged together with the carrier gas from the exhaust pipe 6. It

The cylindrical conical hopper 3 has the function of diffusing the pellets supplied by the carrier gas in the cylindrical portion 1 and contracting the pellets in the conical portion 2 so as to collide and separate the pellets and the fine powder particles. It also has the function of discharging the fine powder thus obtained together with the carrier gas. Therefore, the hopper 3 has a constant cone angle and opening area. The conical portion 2 may have a conical shape as shown in FIG. 1 or may have a pyramidal shape. The cone angle of the conical portion 2 of the cylindrical cone-shaped hopper 3 is preferably 40 to 5 degrees, more preferably 20 to 5 degrees. The opening area of the cylindrical portion 1 of the cylindrical conical hopper 3 is not particularly limited as long as it has an area capable of diffusing the pellets supplied by the carrier gas. The opening area of the exhaust pipe 6 is preferably an area where a flow velocity of 1 to 0.3 times the flow velocity of the carrier gas of the supply pipe 4 can be obtained.

It is preferable that the supply pipe 4 is inserted downward from above the cylindrical hopper 3 and the opening position thereof is below the mounting position of the exhaust pipe 6. The opening area of the supply pipe 4 varies depending on the amount of pellets transported, but the carrier gas flow velocity at the opening of the supply pipe 4 is preferably 10 m / sec or more, more preferably 15 to 30 m / sec. The discharge pipe 5 is attached to the bottom portion of the conical portion 2, and the opening area of the discharge pipe 5 may be the minimum area necessary for discharging the pellets from the discharge pipe 5, and the opening area of the supply pipe 4 may be 0. 3 to 1.0 times is preferable.

Further, the exhaust pipe 6 is attached to the upper portion of the cylindrical weight-shaped hopper 3, and its attachment position may be the upper side wall portion as shown in FIG. 1 or the hopper head portion. As described above, it is important for the separation device A according to the present invention to cause the polymer pellets to fall in the cylindrical conical hopper 3 and to cause the upward flow of the carrier gas containing the fine powder particles. The classification of the polymer pellets is performed, for example, on the longest side of 1.5 to
Fine particles with a diameter of less than 1 mm mixed in 4 mm cylindrical or prismatic pellets are separated and removed. Therefore, the speed required for discharging the fine particles without depositing them in the hopper is set at the upper part of the hopper. Therefore, the opening area of the tubular portion 1 is preferably 1.5 to 3.5 times the opening area of the supply pipe 4.

The types of polymer pellets applicable to the present invention include polyester, polyamide, polyolefin and AB.
These are pellets for fibers such as S, polyphenylene sulfide, and polyacetal, and for molded articles. Further, air, nitrogen gas, or the like is used as the carrier gas.

[0014]

The device having the above structure operates as follows. The polymer pellets containing fine particles are fed together with the carrier gas into the supply pipe 4
When discharged from the cylindrical conical hopper 3 into the cylindrical conical hopper 3, it diffuses in the cylindrical part 1 of the hopper and then contracts at the conical part 2 (or the conical part) to repeatedly collide with the wall surface and collide with the pellets. The relatively heavy pellets fall without being scattered upward and are discharged from the discharge pipe 5 at the bottom, and the relatively light fine particles are discharged from the exhaust pipe 6 above together with the carrier gas. The pellets fall in the hopper B, the carrier gas rises, and the fine powder particles are separated. The cone angle of the conical portion 2 (or the pyramidal portion) and the opening area of the cylindrical portion 1 and the discharge pipe 5, depending on the opening area of the exhaust pipe 6, these may be appropriately set depending on the type of pellets to be applied.

[0015]

EXAMPLES The effects of the apparatus of the present invention will be described below with reference to examples. Example 1 As a separating device, the device structure shown in FIG. 1 was used, the diameter of the cylindrical portion 1 of the cylindrical conical hopper 3 was 200 mm, the cone angle of the conical portion 2 was 8 degrees, and the supply pipe 4 is a pipe with a diameter of 125 mm, and the tip of the opening is 10
A device having a diameter of 100 mm and an exhaust pipe 6 having a diameter of 150 mm was used. Then, 4 mm square columnar nylon polymer pellets containing 800 to 1000 ppm of fine powder of 1 mm or less were supplied at a rate of 4000 kg / h and 2500 kg at a flow rate of 25 m / s together with a carrier gas.

As a result of separating the fine particles in the pellet discharged from the lower discharge pipe 5 with a standard sieve, the amount of fine particles less than 1 mm is 85 to 100 ppm, and the carrier gas discharged from the upper exhaust pipe 6 No normal pellets were found in the fine powder and the fine powder was not accumulated in the hopper. Example 2 A separating device having the device structure shown in FIG. 1, and the diameter of the cylindrical portion 1 of the cylindrical conical hopper 3 is 80 mm, and the conical portion 2
Has a cone angle of 8 degrees, the supply pipe 4 is a pipe with a diameter of 50 mm, and the tip of the opening is 100 mm from the mounting portion of the exhaust pipe 6.
A device having a diameter of 40 mm for the discharge pipe 5 and a diameter of 80 mm for the exhaust pipe 6 was used. 600 kg / kg of polyester polymer pellets (diameter 2.5 mm, length 2.5 mm) in which 40 to 30 ppm of fine particles of 1 mm or less are mixed
It was continuously supplied with the carrier gas at a flow rate of 23 m / s for 1 year.

As a result of separating the fine particles in the pellet discharged from the lower discharge pipe 5 with a standard sieve, the amount of fine particles less than 1 mm is 2 to 4 ppm, and the carrier gas exhausted from the upper exhaust pipe 6 No fine pellets were found in the normal pellets, and there was no accumulation of fine pellets in the hopper.

[0018]

EFFECTS OF THE INVENTION By using this apparatus, the pellet dropping and the fine powder in the cylindrical conical hopper can be performed without providing a special collision part in the separation tank and only by the carrier gas of the polymer pellets. It is possible to effectively generate an ascending flow containing, and it is possible to continuously separate and remove only fine particles from the polymer pellets with high productivity.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an example of an apparatus for separating and removing fine particles of polymer pellets according to the present invention.

[Explanation of symbols]

1 ... Cylindrical section 2 ... 3 ... Cylindrical conical hopper 4 ... Supply pipe 5 ··· Discharge pipe 6 ... Exhaust pipe

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Claims (9)

(57) [Claims] And 1. A lower portion cone-shaped or pyramidal shape formed into a cylindrical conical hopper, a supply pipe which is inserted into the hopper from the hopper above the outlet tube of the hopper bottom, said hopper <br/> upper portion polymer pellets of a fine powder or granular material separating device, characterized in that it is composed of an exhaust pipe provided in the side wall portion of the. 2. The apparatus for separating and removing fine particles of polymer pellets according to claim 1, wherein the cylindrical cone-shaped hopper has a cone angle of 5 to 40 degrees. 3. The fine particles of polymer pellets according to claim 1, wherein the tip of the supply pipe inserted into the hopper from above the cylindrical conical hopper is located below the exhaust pipe. Body separation and removal device. 4. The apparatus for separating and removing fine particles of polymer pellets according to claim 1, wherein the opening area of the discharge pipe is 0.3 to 1.0 times the opening area of the supply pipe. . 5. The fine powder particles of the polymer pellet according to claim 1, wherein the opening area of the upper cylindrical portion of the hopper is 1.5 to 3.5 times the opening area of the supply pipe. Body separation and removal device. 6. The polymer pellets containing fine powder or granular material from a supply pipe below section is inserted from above of the tubular conical hopper forms a cone-shaped or pyramidal shape in the hopper along with the carrier gas by feeding the pellets were discharged from the discharge pipe of the hopper bottom, a polymer characterized by discharging the fine powder and granular material with a carrier gas from <br/> exhaust pipe provided in the side wall portion of the hopper upper Method for separating and removing fine particles of pellets. 7. without providing the pellet impingement plate in said hopper, polymer fine granular material separating and removing method of the pellets according to claim 6, wherein the separating the fine powder granules only in the transport gas stream. The opening area of wherein said exhaust pipe, polymer pellets of fine according to claim 6, wherein the 1 to 0.3 times the flow rate of the carrier gas flow rate of the supply tube is the area obtained Method for separating and removing powder and granules. 9. The carrier gas flow velocity at the opening of the supply pipe is 1
Polymer fine granular material separating and removing method of the pellets according to claim 6, wherein a is 0 m / sec or more.