JPH0692085B2 - Pelletizer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pelletizer (also referred to as a strand cutter) for cutting an organic polymer material formed into a strand into pellets.

[0002]

2. Description of the Related Art Most of thermoplastic resins are once pelletized and then processed into plastics molded articles. One of the pelletizing methods is the strand cut method. In this method, the polymerized molten resin is extruded from a porous die using an extruder or a gear pump, and the string-shaped strand is solidified, cooled, and then cut into short pieces with a pelletizer. Generally, in a pelletizer, a plurality of cooled strands are sandwiched by two take-up rolls and continuously delivered onto a strand running surface, and cut by a fixed blade attached to the tip of the strand and a rotary blade facing the strand. It is structured.

[0003]

By the way, even if the strand is sufficiently cooled, the cutting portion of the pelletizer, especially the cutting edge portion, becomes a considerably high temperature by vigorous cutting work. When the cutting edge becomes hot, the hardness of the cutting edge decreases,
Further, the clearance set between the rotary blade and the tip of the fixed blade is deviated and the cutting function becomes dull, resulting in miscuts and oblique cutting. Furthermore, it is not uncommon that the resin pieces scattered on the strand traveling table are heated and fixed on the table, and the effect of this is that the strands cannot be fed smoothly and the cutting portion is blocked to make the pelletizer inoperable. To solve this problem, it is necessary to cool the cutting part. However, due to the mechanism, the cutting area is very narrow, and many strands run at high speed toward the rotating blade that rotates at high speed.Therefore, install some special device to solve the above problem. Not only is it very difficult, but it can cause further trouble.

By the way, the specifications and inventions disclosed in Japanese Utility Model Laid-Open No. 56-42895 and Japanese Patent Application Laid-Open No. 3-61507 give a little hint as to the cooling of the cutting portion. The former proposes that a heat pump is attached to the shaft of a rotary blade to remove heat, and the latter proposes to spray a liquid from above to remove heat. However, each of the pelletizers has a complicated structure, and there are problems such as the inability to cool the fixed blade side and the use of liquid. Therefore, the present inventor has completed the present invention by researching a pelletizer that does not have a complicated structure, maintains stable cutting ability over a long period of time, and has few troubles and is easy to use.

[0005]

As a first aspect of the present invention, in a pelletizer for cutting a strand delivered from a take-up roll between a rotary blade and a fixed blade, a root portion of a rotary blade cover is provided. (EN) A pelletizer characterized in that it is rotatably attached to a mounting base, a tip portion of the cover is brought close to a cutting portion, and a gas blowing nozzle is provided at the tip portion toward the cutting portion.

As a second aspect of the invention, in a pelletizer for cutting the strand delivered from the take-up roll between the rotary blade and the fixed blade, the base of the take-up roll cover is rotatably attached to a mount. There is provided a pelletizer in which a tip portion of the cover is brought close to a cutting portion and a gas blowing nozzle is provided at the tip portion toward the cutting portion.

[0007]

FUNCTION AND EXAMPLE OF EMBODIMENT The present invention will be described below with reference to the drawings. FIG. 1 is a schematic view showing a longitudinal section of an embodiment example of a pelletizer of the first invention and FIG. 2 is a schematic view thereof. Figure 3
[Fig. 2] is a view of the tip portion of the rotary blade cover of Fig. 1 viewed from the direction A.

First, although not shown, the strands cut by the pelletizer are usually a plurality of strands, and the upper roll 3 (23) and the lower roll 4 pass through the chute 1 (corresponding to 21 in FIG. 2). (24) and take-up roll 2 (22), and scraper 5 (25)
While being prevented from being wound around the lower roll 4 (24), the strand running surface 6 (26) is moved toward the fixed blade 8 (28) attached to the tip of the strand, that is, the cutting portion 7 (27). Is sent. The strand sent to the cutting unit 7 (27) is cut into a predetermined length by the rotary blade 9 (29) having a gear-shaped blade and the fixed blade 8 (28). The upper roll 3 (23) and the rotary blade 9 (29) have covers 10 (30) and 11 (3) respectively mainly for safety.
1) is installed.

Now, the pelletizer of the first invention will be described. The rotary blade cover 11 is designed to be opened upward for the purpose of facilitating maintenance and inspection of the rotary blade 9, adjustment of the blade clearance of the cutting portion 7, and cleaning.
3 is directly or indirectly rotatably mounted on the mounting base 14. In the present invention, the base portion of the cover means a mounting portion of the cover, and if the tip end portion of the cover opens upward, its position is not important. And the cover 11
The tip portion of the is close to the cutting portion 7, and a nozzle 15 for blowing gas is provided at the tip portion. The nozzle 15 is brought close to the cutting portion 7 to the extent that it does not hinder the running of the strand,
The blowing direction of the gas is directed toward the cutting section 7. Cover 11
Since the tip of the is attached rotatably, although it is close to the cutting portion 7, even if a strand of an abnormal size is fed in for some reason, it is naturally pushed up,
Does not develop into a big trouble. The gas blown out from the nozzle 15 has a function of cooling the fixed blade 8 and the rotary blade 9 and removing pellet waste on the strand running surface 6. The gas that blows out is usually air. The shape of the nozzle 15 may be, for example, a slit shape as shown in FIG. 3, or may be a nozzle formed by forming small holes at appropriate intervals in a pipe attached in parallel to the tip end portion. A slit shape is preferable for evenly blowing out the gas. Protrusions 16 (not shown in FIG. 1) may be provided at both ends of the tip of the cover 11 so that the nozzle 15 does not contact the strand running surface 6 and block the strand passage. For supplying the gas blown out from the nozzle 15, for example, a conduit may be attached to the side face of the rotary blade cover 11, but as shown in FIG. If the passage 17 is provided and the nozzle 15 is formed into a slit shape, there is an advantage that a special space is not required and the gas can be blown out uniformly, which is preferable. Reference numeral 18 is a connection port for supplying gas.

In the pelletizer of the second invention, the tip portion of the take-up roll cover 30 is close to the cutting portion 27,
Nozzle 3 that blows gas toward the cutting portion 27 at its tip
5 is provided. The cover 10 is opened upward so as to facilitate maintenance and inspection of the take-up roll 22, adjustment of the clearance of the blade of the cutting section 27, and cleaning.
2 is directly or indirectly rotatably mounted on the mounting base 34. For example, an arm is rotatably attached to the mount 34, and the cover 10 is rotatably attached to the arm. Shoot 21 and upper roll 2 on this arm
3 is attached, the chute 21 and the upper roll 23 can be moved upward at the time of inspection and adjustment, which is extremely convenient. Other conditions are in accordance with the above-mentioned first invention.

[0011]

[Example] A commercially available pelletizer (TMS type manufactured by Tanaka Iron Works Co., Ltd.) was attached with a fixed blade cover having a nozzle for blowing gas at the tip, which has almost the same structure as shown in FIG. The effects of the present invention were confirmed. The nozzle width of this pelletizer is about 150 mm, and the clearance between the fixed blade and the rotary blade is 4/100 before the operation.
It was adjusted to mm. With this pelletizer, the diameter is about 3
21 pieces of polyamide polyamide strands are aligned, drawn with a take-up roll at a speed of about 50 m / min, guided onto a strand traveling table, and blown with 1.2 m ³ of cooling air at 10 ° C. from the nozzle, It was cut to a length of 3 mm. After continuous operation for 2.5 hours, there was no trouble and the cut surface of the pellet was as good as at the beginning. A small amount of pellets were scattered on the strand running surface.

Subsequently, for comparison, using the same pelletizer, the fixed blade and the rotary blade were re-polished, the clearance between the blades was readjusted to 4/100 mm, and cooling air was not blown in. The strand was cut with. Approximately 1.5 hours after the start of operation, both blades contacted each other, so the operation was stopped. Immediately before the shutdown, the cut surface of the pellet was slightly sloping and was not very good. More pellets than the above were scattered on the strand running surface.

[0013]

In the pelletizer of the present invention, during operation, the cutting portion of the pelletizer, especially the cutting edge portion, is caused by the gas constantly blown from the nozzle attached to the tip of the rotary blade cover or the take-up roll cover. It is always cooled, and there is no phenomenon of high temperature at the cutting edge, which was a problem with conventional pelletizers. For this reason, the hardness of the blade is not lowered, and the clearance between the rotary blade and the fixed blade tip is not changed, and stable cutting can be performed for a long time. Also, the strand support base is not heated, and most of the resin pieces scattered on the strand support base are removed from the base by the blown gas, and are not fixed on the base to prevent smooth running of the strand. .

Further, since the nozzle provided in the pelletizer of the present invention is attached to the rotary blade cover or the take-up roll cover which is originally attached, the circumference of the cut portion is narrowed and the running of the strand is hindered. There is no such thing. Moreover, since these covers are rotatably attached to the attachment base,
Even if there is an abnormal portion that cannot pass as it is between the front end of the cover and the strand supporting surface, the cover can be pushed upward and easily pass. Therefore, even if the nozzle is brought close to the cutting portion, no trouble will occur. In the pelletizer of the present invention, the nozzle can be installed very easily, no complicated work is required during operation, the operation is safe, and no complicated mechanism is required, which is economical.

[Brief description of drawings]

FIG. 1 is a schematic view showing a vertical cross section of an example of an embodiment of a pelletizer of the first invention.

FIG. 2 is a schematic view showing a vertical cross section of an embodiment of the pelletizer of the first invention.

FIG. 3 is a front end portion of the rotary blade cover viewed from the direction A in FIG.

[Explanation of symbols]

1, 2: Chute 2, 22: Take-up roll 3, 23: Upper roll 4, 24: Lower roll 5, 2
5: Scraper 6, 26: Strand running surface 7, 27: Cutting part
8, 28: Fixed blade 9, 29: Rotating blade 1 10, 30: Upper roll cover
11, 31: rotary blade cover 12, 32: upper roll cover root portion 13, 33: rotary blade cover root portion
14, 34: Mounting base 15, 35: Nozzle 16:
Protrusions 17, 37: Gas flow path 18, 38: Connection port 1
9: Handle

Claims (2)

[Claims] 1. A strand delivered from a take-up roll,
In a pelletizer that cuts between a rotary blade and a fixed blade, the root of the rotary blade cover is rotatably attached to a mounting base, the tip of the cover is brought close to the cut, and the tip is directed toward the cut. Pelletizer characterized by having a gas blowing nozzle. 2. A strand delivered from a take-up roll,
In a pelletizer that cuts between a rotary blade and a fixed blade, the base of the take-up roll cover is rotatably attached to a mounting base, the tip of the cover is brought close to the cut, and the tip is directed toward the cut. Pelletizer characterized by having a gas blowing nozzle.