JPH0246130B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a granulation device attached to the tip of a thermoplastic resin extruder. This granulating apparatus passes the molten resin extruded from an extruder through a die, cuts it into pellets, cools it, solidifies it, and granulates it.

(Prior Art) A conventional granulation device includes a horizontal underwater granulation device as shown in FIG. The cutter shaft 7 is set on an extension of the extruder screw 2, which is a horizontal shaft. The molten resin extruded from the extruder 1 enters the die holder 3, is filtered by the screen 4, and flows out from the die 5 into the cutter box 8, where it is transferred to the cutter head 6 attached to the cutter shaft 7.
pelletized by Further, cooling water 10 is circulated within the cutter box 8 to cool and solidify the pellets. That is, the conventional device is a horizontal underwater granulation device.

(Problems to be Solved by the Invention) In the conventional device, when the cooling water 10 is circulated in front of the die 5, especially when handling resin with a high melting coefficient, at the start of operation or when the operation is temporarily stopped, The resin drips into the cutter box 8 from the lower die hole, causing so-called resin dripping. Furthermore, when the operation is stopped, the resin level in the die holder 3 decreases, and the cooling water 10 flows back into the die holder 3 through the upper die hole, lowering the resin temperature, and when the operation is restarted, the resin flows into the die nozzle. A so-called clogging phenomenon occurs. The conventional apparatus thus had the disadvantage of causing resin dripping and clogging phenomena.

The present invention aims to overcome the drawbacks of the conventional apparatus described above, and provides a granulation apparatus that eliminates resin dripping and clogging phenomena. The applicant has already invented and applied for a vertical underwater granulation device for the above purpose (patent application no.
No. 67606). As shown in FIG. 2, the invention according to the earlier application is such that the cutter shaft 7 of the cutter unit 9 is vertically disposed orthogonal to the extruder 2, and an adapter 11 is provided at the tip of the extruder to convert the molten resin flow path upward. It is characterized by the fact that it has been provided. Further, in the cutter box 8, the molten resin is cut underwater as in the conventional apparatus. The present invention further improves the invention of the prior application, prevents the die from being cooled by water, and further reduces the clogging phenomenon of the die nozzle.

(Means for Solving the Problems) The present invention provides a vertical granulation device in which the bottom surface of a cutter box is externally covered with a die holder, and the outer circumference of the die holder on the bottom surface is used as a circumference that serves as a cooling water flow path. This is an aerial granulation device equipped with a cutter box having a shaped groove and a large number of cooling water injection holes or water injection slits provided on the circumferential portion of the upper surface of the cutter box corresponding to the groove. This configuration solves the above problems.

(Function) By adopting the above-described configuration, the present invention can form a shower curtain in which cooling water falls in a waterfall shape on the inner circumferential side of the cutter box, and also allows the cooling water to be cut by the rotation of the cutter head. Each pellet of molten resin flies outward and is cooled and solidified by the shower curtain.

(Example) The configuration of an example of the present invention is as shown in FIG.
This is an improved version of the cutter box 8 in the above-mentioned vertical underwater granulation device. As shown in the figure, the bottom of the cutter box 8 is sheathed so as to surround the die holder 3 and the die 5, and the bottom surface of the outer periphery of the die holder 3 is a circumferential groove 12. is a flow path in which cooling water 10 for cooling the pellets stays and reaches a discharge port 17. Further, in the disc 13 on the upper surface of the cutter box 8, water injection holes 14, 14 for cooling water 10 are arranged in two circumferential rows in an area corresponding to the groove 12.
A large number of them are arranged alternately. In addition, the water injection hole 14
may be formed into a slit shape. Furthermore, a circumferential jacket 15 is placed so as to cover the circumferential water injection holes 14 , 14 , and a 1/2-inch jacket is placed on the upper surface of the jacket 15 .
At least two inlets 16 for cooling water 10 are provided. That is, the cooling water 10 for cooling the pellets
falls into the groove 12 from the circumferential water injection holes 14, 14 in a waterfall shape, forming a shower curtain 20. On the other hand, the molten resin flowing into the cutter box 8 from the die 5 is pelletized by the cutter head 6, and centrifugal force is applied by the rotation of the cutter head 6.
Each pellet flies outward, passes through the shower curtain 20, and falls into the groove 12 where the cooling water 10 is retained. Therefore, the molten resin is pelletized at a location where there is no cooling water 10, that is, in the air, and is cooled and solidified by the shower curtain 20. Further, a discharge port 17 for the cooling water 10 is provided on the outer surface of the groove portion 12 of the cutter box 8. Furthermore, a water circulation pipe 18 is provided at the center of the adapter 11 from its lower end to the upper surface of the central part of the die 5, so that when resin adheres to the blade of the cutter head 6 or there is a concern that it may,
A small amount of water is supplied to the top of the die to prevent resin from adhering.

(Effects of the Invention) With the above-described structure and operation of the present invention, it is possible to eliminate the resin dripping and clogging phenomena that are the drawbacks of the conventional apparatus described above, and it is possible to produce pellets having high and uniform quality. The effect is particularly remarkable when granulating thermoplastic resins with a high melting coefficient. Furthermore, in order to prevent resin from adhering to the blade of the cutter head, a water pipe can be installed from the lower end of the adapter to the upper surface of the central part of the die, if necessary. Further, in the present invention, unlike the conventional apparatus and the apparatus according to the invention of the prior application described above, the die is not directly cooled by cooling water, so that the clogging phenomenon can be almost completely eliminated.

[Brief explanation of drawings]

FIG. 1 is an explanatory cross-sectional view of an apparatus according to an embodiment of the present invention, FIG. 2 is a vertical granulation apparatus, and FIG. 3 is a conventional (horizontal) apparatus. 1... Extruder, 2... Screw, 3... Die holder, 4... Screen, 5... Die, 6...
...Cutter head, 7...Cutter shaft, 8...Cutter box, 9...Cutter unit, 10
... Cooling water, 11 ... Adapter, 12 ... Groove,
13... Top disk, 14... Water injection hole, 15... Jacket, 16... Inlet, 17... Outlet, 1
8...pipe, 20...shower curtain.

Claims (1)

[Claims] 1 In a vertical aerial granulation device, the die nozzle is located above the molten resin level in the extruder and faces upward, and the bottom surface of the cutter box is covered with a die holder, and the outer peripheral part of the die holder on the bottom surface is covered with a die holder. The cutter box is characterized by having a circumferential groove that serves as a flow path for cooling water, and a plurality of water injection holes or water injection slits provided in a circumferential portion of the upper surface of the cutter box that corresponds to the groove. Vertical aerial granulation equipment.