JPS62279905A - Granulator - Google Patents

Abstract

PURPOSE:To improve operation efficiency and to make structure simple and inexpensive by preventing adhesion of pellets to a cutter at the time of cutting off of a material, by cooling the cutter by providing a cooling medium passage within the cutter. CONSTITUTION:A cooling medium blow-off port 5a of a cooling medium passage 5 of a cutter 4 is opened on the bottom of the cutter 4, a cooling medium blown off through the blow-off port 5a is blown against pellets cut off on the edge 4h of a blade of the cutter 4 and along with cooling of the pellets the pellets are blown off toward the outside of a rotation of the cutter 4. A line of the edge 4h of a blade is formed so as to possess a back rake angle theta in the direction of a normal line of a rotary circle on the outside of the line of the edge 4h of the blade. A component through which the pellets are blown off outside is applied to the pellets formed through cutting off because the line of the edge 4h possesses the back rake angle theta. Sprayer 9 is provided by surrounding a space where the cutter 4 is rotated. The sprayer 9 is constituted of a high- pressure water inlet 9a, an annular high-pressure water passage and a spray nozzle 9c, and the circumference of the cutter 4 is cooled further by spraying through the spray nozzle 9c.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention (Field of Industrial Application) This invention is first used in the technical field of processing plastic materials,
In particular it concerns a device for granulation.

(Prior art) To granulate a plastic material, a plasticized molten material is extruded through an extrusion hole provided in a die plate, and a cutter that slides on the exit surface of the hole extrudes the extruded molten material. A device adapted to cut the strands is used.

However, in conventional granulation equipment, the cutter is heated by heat conduction due to the heating device used to melt the plastic material, and the cut granules (pellets) are an intermediate between melting and assimilation. (semi-molten state), and because of the adhesive surface of this pellet, it adheres to the cutter and cannot be peeled off.

As a result, subsequent pellets adhered to the preceding pellets one after another, making it difficult to achieve satisfactory granulation.

(Problem to be solved by the invention) When the plastic material passes through the extrusion hole of the die plate, it is necessary to maintain the area around the extrusion hole at a certain high temperature to maintain its fluidity. If you try to prevent pellets from sticking by keeping the cutter itself at a low temperature, you won't be able to make the area around the extrusion hole very hot, which will impair the fluidity of the material (which will also worsen workability. However, there was a problem in that good continuous operation was not possible over a long period of time.

In particular, when granulating single materials using high-crystalline resins or composite materials using other materials as fillers, the allowable range of the melting temperature of the material is extremely narrow (temperature control is important, and the above-mentioned The problem becomes obvious.

This invention attempts to solve these problems.

(Means for solving the problems) Means for solving the above problems will be explained with reference to the drawings.

The granulating device 1 of the present invention includes a die plate 3 provided with an extrusion hole 2, and a cutter 4 sliding on an exit surface 3a of the extrusion hole 2.
, and a refrigerant passage 5 configured to conduct refrigerant into the cutter 4.

(effect) The effects of the above means will be described below.

The die plate 3 is heated to suitably heat the material, and the molten material is continuously extruded from the extrusion holes 2. On the other hand, the forceps 4 are cooled by the refrigerant in the refrigerant passage 5, and the pellets cut and formed by the cutter 4 are cooled and lose their adhesive strength, so that they do not stick to the cutter 4 (they detach one after another and continue to form). A good pellet forming operation is performed.

(Embodiment) The first embodiment of the present invention will be further described in FIGS. 1 to 3 below.
This will be explained in detail with reference to the drawings.

6 is a known screw extruder. 6a is a cylinder, 6b is a screw, 6C is a die plate, 6d is a breaker plate, 6e is a nozzle, and 6f' is a heater.

The main body (die) 1a of the granulating device 10 is provided with a manifold 7 through which the material passes, and the manifold 7 is connected to the outlet of the nozzle 6e as shown. The manifold 7 communicates with a cylindrical passage 7b for the material, and a die plate 3 is attached to the lower end of the cylindrical passage 7b.
Ru. 1b is a heater for the main body 1a.

The die plate 3 has extrusion holes 2 opened at equal intervals on the pitch circle on the same pitch circle as the cylindrical passage 7b.

Also provided within the die plate 3 is a heater (cartridge heater) 3b.

A plurality of cutters 4 are attached symmetrically to an arm 4b integrally provided at the lower end of a rotating shaft 4a, and are configured as rotary blades. The rotating shaft 4a is rotatably supported on the main body 1a by a bearing 4C, and has a refrigerant supply hole 4d at its center.
is provided.

The refrigerant supply hole 4d communicates with the refrigerant passage 5 in the cutter 4.

A known rotary joint 4 is provided at the upper end of the rotating shaft 4a.
e is provided, and the refrigerant supply hole 4d is communicated with a refrigerant supply source 4f via the rotary joint 4e. As the refrigerant supply source 4f, a means for pumping cold air or cold water is used.

Note that between the outlet surface 3a and the arm 4b, a plate-shaped heat insulating rotating plate 4g serving as a heat insulating material is fixed to the rotating shaft 4a (the heat of the die plate 3 is not transferred to the cutter 4, It is configured as follows.

A power means 8 for rotationally driving the rotating shaft 4a is connected to the rotating shaft 4a.

To describe the details of the cutter 4, the refrigerant passage 5 is connected to the cutter 4.
The refrigerant outlet 5a is opened on the lower surface of the cutter 4, and the refrigerant blown out from the outlet 5a also flows through the cutting edge 4h of the cutter 4.
The pellets are blown onto the cut pellets, cooling the pellets, and blowing the pellets toward the outside of the rotation of the cutter 4, so that the pellets have a receding angle θ.

By having this receding angle θ, the cut pellets are subjected to a force component that causes them to be blown outward.

A spray device 9 is provided surrounding the space in which the cutter 4 rotates. The spray device 9 consists of a high-pressure water port 9a, an i-shaped high-pressure water passage 9b, and a spray nozzle 9C,
The spray from the spray nozzle 9C attempts to further cool the area around the cutter 4. The above-mentioned heat insulating rotary plate 4g removes this spray by centrifugal force and prevents the die plate 3 from being cooled.

Next, the second embodiment will be described with reference to FIGS. 4 and 5, mainly focusing on the differences from the first embodiment.

In this embodiment, a plate-shaped heat insulating material 10 is further provided on the side of the die plate 3 facing the cutter 4. The heater 3b is provided with a heat medium passage 3C, and the heat medium circulates to heat the die plate 3.

Further, the width of the exit surface 3a facing the cutting edge 4h of the cutter 4 is made small to minimize the conduction of high heat from this portion to the cutter 4.

The rest is substantially the same as the first embodiment, and the same components are given the same reference numerals.

(Effects of the Invention) As described above, the granulation device of the present invention cools the cutter to ensure a temperature difference between the cutter and the die plate, so that the melting temperature range is Even if the material is extremely narrow, when cutting the material to form pellets, the pellets will not stick to the cutter (), as good pellets are continuously formed, improving work efficiency. Not only can it be used, but it can also be implemented by modifying a conventional granulation device, and it has the advantage of being simple in structure, inexpensive, and available.

[Brief explanation of the drawing]

The drawings all illustrate embodiments of the present invention, and FIGS. 1 to 3 show the first embodiment. FIG. 1 is a vertical side view, and FIG. 2 is a view taken from the FIG. 3 is a perspective view of a portion of the cutter. 4 and 5 show a second embodiment, in which FIG. 4 is a vertical sectional side view of a main part, and FIG. 5 is a view taken along arrow v--■ in FIG. 4. DESCRIPTION OF SYMBOLS 1... Granulation device, 2... Extrusion hole, 3... Die plate, 3a... Exit surface, 4... Cutter, 5...
Refrigerant passage.

Claims (4)

[Claims] (1) The plasticized melt is extruded through an extrusion hole provided in a die plate, and the extruded strand is cut between the exit surface and the extrusion hole by a cutter that slides on the extrusion hole. 1. A granulating device configured to cut using a cutter, characterized in that a refrigerant passage is provided in the cutter to cool the cutter. (2) The granulation device according to claim 1, wherein the cutter is provided with a refrigerant outlet, and the refrigerant is sprayed onto the pellets cut by the cutter. (3) The cutter is a rotary blade, and the cutting edge line at the tip of the cutter has a receding angle on the outside with respect to the normal direction, as claimed in claim 1 or 2. Granulation equipment as described in section. (4) The granulation device according to claim 1, wherein a plate-shaped heat insulating material is disposed on the side of the die plate facing the cutter.