JPS6220260Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a cutter device for underwater granulation. A granulation device is attached to the tip of the thermoplastic resin extruder, which uses a die and a cutter knife on the front of the die to cut the strands of resin extruded through the countless holes of the die into pellets underwater using the rotating cutter knife. .

Conventionally, this type of underwater granulation equipment includes, for example, the equipment filed by the present applicant (publication of Utility Model Publication No. 55-49223); It has the flow shown in FIG. That is, a cutter injection hole 11 is provided at the center of the cutter shaft 4, and hot water 14 flows through the injection hole 11 as shown in the figure, flows out to the front of the die 2, and merges with the hot water flowing inside the cutter box.
It flows between the cutter knife 6 and the front surface of the die 2. This flow of hot water 14 lubricates the mechanical seal 7 at the contact surface between the cutter shaft 4 and the cutter box 10 and prevents resin from being caught between the cutter knife 6 and the front surface of the die 2 and resulting in poor cutting. However, if the cutter shaft 4 is rotated without the hot water 14 flowing, the mechanical seal 7 cannot be protected. On the other hand, if the extrusion of the molten resin is started with the hot water 14 flowing to the front of the die 2, the molten resin will be It solidifies in the die hole, causing clogging, making it impossible to obtain good pellets. Therefore, it is necessary to fill the die hole with molten resin,
In the conventional apparatus, the hot water 14 is flowed while the molten resin is dripped into the cutter box 10 from the die hole. On the other hand, the hot water 14 causes the cutter shaft 4 to
Because the shaft expands thermally and the shaft length becomes longer, it becomes necessary to perform a so-called shaft lengthening operation to clarify the gap between the cutter knife 6 and the front surface of the die 2, resulting in a loss of time (30~
60 minutes), and during this time the resin remains dripping and the material is wasted.

The present invention aims to overcome the drawbacks of the conventional devices mentioned above. The present invention is characterized in that the flow of hot water inside the cutter shaft and the flow of hot water spouted into the center area of the front face of the die are separated and separated into separate systems. Hereinafter, the present invention will be described in Example 2.
This will be explained based on FIG.

The cutter shaft 4 is provided with a pipe 8 at its center, and further provided with a center hole surrounding the pipe 8, the tip on the die side is closed, and a cutter holder 5 and cutter knives 6 are installed radially. On the other hand, a die face injection hole 3 is formed in the front face of the die 2 and penetrates from the upper part between the die nozzles to the center of the die front face. That is, the hot water 14 flows into the cutter shaft 4 from the cutter water inlet 8, circulates backwards around the outer circumference from the tip of the cutter shaft 4, and flows out from the cutter water inlet 9. This flow of warm water warms the cutter shaft 4 and causes the mechanical seal 7 to operate with lubrication. On the other hand, hot water 14' flowing through the water injection hole 3 on the die surface flows into the cutter box 10 from the center of the front face of the die, joins with the hot water 13 flowing inside the box, and flows between the cutter knife 6 and the front face of the die 2. This flow through the die face injection port 3 eliminates the negative pressure generated in the center area of the front face of the die 2 due to the rotational force of the cutter knife 6, and the cut pellets are smoothly transferred to the cutter box without staying in this area. It can be taken out more easily.

As mentioned above, in this invention, the flow of hot water inside the cutter shaft and the flow of hot water spouted to the center area of the front surface of the die are separated, so the flow of hot water inside the cutter shaft raises the temperature of the cutter shaft. The shaft extension work required in the past is no longer necessary, and the mechanical seal operates smoothly even when the cutter is rotated. Furthermore, by advancing the cutter knife toward the die surface side and rotating it, hot water can flow into the cutter box at the same time as the molten resin is extruded from the die nozzle, and the hot water can also be spouted into the center area of the front face of the die. All the shortcomings of conventional devices can be solved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a cutter shaft of a conventional device, FIG. 2 is a longitudinal sectional view of a cutter shaft of an embodiment of the present invention, and FIG. 3 is a longitudinal sectional view of the same embodiment. 1...Die holder, 2...Dice, 3...Die surface water injection hole, 4...Cutter shaft, 5...Cutter holder, 6...Cutter knife, 7...Mechanical seal, 8...Cutter water injection inlet, 9...
Cutter water injection outlet, 10... cutter box,
11... cutter water injection hole, 12... molten resin, 1
3... Warm water flowing inside the cutter box, 14...
...Hot water flowing through the water injection hole on the cutter shaft, 14'...Hot water flowing through the water injection hole on the die surface.

Claims (1)

[Scope of utility model registration request] An underwater granulation device characterized in that a water injection hole whose end on the die side is closed is provided in the cutter shaft, and a water injection hole is provided in the die that extends from the outer periphery to the center of the front surface of the die.