JPH02152538A - Device for pelletizing viscous material - Google Patents

Abstract

PURPOSE:To surely detach a pellet from the tooth of a cutter roll by arranging a cage roll rotating in synchronization with the cutter roll in parallel with the cutter roll and displacing the cage roll slightly upward. CONSTITUTION:The strand of a viscous material is conveyed by an endless belt 2 while being cooled, and cut into pellets by the teeth 31 of the cutter 3. The cage roll 4 provided with many pins 41 having the same pitch as that of the teeth 31 of the cutter roll is arranged in parallel with the cutter roll 3, and displaced slightly upward from the roll 3. When the teeth of the cutter roll 3 is at the position for cutting the strand of the viscous material, the cutting is not disturbed by the pins 41 of the cage roll 4, the pins are raised up from the bottom of the tooth space of the cage roll 4 after cutting, and the pellet formed by cutting is surely detached from the teeth of the cutter roll.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an apparatus for pelletizing sticky substances such as petroleum pitch and coal pitch. [Prior Art] Petroleum pitch and coal pitch, which are by-products of processing petroleum tar, coal tar, etc., have opened up the possibility of being used as raw materials for producing carbon fibers, for example. There are several ways to produce carbon fiber from pitch.
A common method is to once form pellets, spin them, and then fire and carbonize them. Therefore, a technology is needed to first granulate petroleum pitch or coal pitch into pellets that are easy to handle. However, unlike synthetic resins, pitch is not easily pelletized. Synthetic resins can be pelletized by various pelletizing techniques such as the water tank strand method, hot cut method, and underwater method, but pitch cannot be pelletized by any of these methods. This is because the temperature range in which pitch can be plastically processed is narrower than that of synthetic resins, the viscosity of the molten material is extremely low, and the solidified material is brittle and crumbles easily. One of the inventors set out to overcome this difficulty and establish a technology for pelletizing pitch, and as a result of various researches, he invented an effective granulating device, which he has already disclosed (in Japanese Patent Application Laid-Open No. (Sho 63-11839). The device extrudes molten pitch in the form of a strand, receives it with a cooling means, typically an endless metal belt, and transports it while cooling it. It is cut with a cutter roll or the like. The key point is that the cooling conditions can be adjusted, which makes it easier to cut the strands under the narrow conditions that allow plastic processing. The above-mentioned equipment is useful, but it is difficult to put it into practical use, especially when trying to produce large pellets,
When the belt was moved faster and the cooling was made more powerful in order to increase production speed, there were times when the pellets adhered to the teeth of the cutter roll and were difficult to fall off.

[Problem to be solved by the invention]

An object of the present invention is to provide an apparatus that can eliminate such troubles and produce pellets of any size from a sticky substance such as pitch at a high production rate. [Means for Solving the Problems] The apparatus for pelletizing a sticky substance of the present invention is shown in FIG. 1 and FIG. 2 as a whole, and in FIG. 3 and FIG. As shown in the figure, a means for extruding the melted adhesive substance in the form of a strand, such as a strand die (1) of an extruder, a means for receiving the extruded strand (S) of the adhesive substance and transferring it while cooling it; Then, the sticky substance is made into pellets by an endless belt (2) and a cutter roll (3) equipped with a large number of teeth (31) projecting in the radial direction, which cuts the transferred strands into pellets. In the machine for cutting, a large number of parallel pins (4
1) are arranged in a cage shape, and the cage roll (4) has an inner diameter larger than the outer diameter of the bottom (32) of the tooth groove of the cutter roll, and its axis is parallel to the axis of the cutter roll, and there is a slight slit. The cutter roll (3) is installed eccentrically above the
The two are assembled so that the cage roll (4) is rotated as the cutter roll rotates, and each pin (41) of the cage roll is in a position where the teeth (31) of the cutter roll cut the strand (S) of the sticky substance. It is located at the bottom of the tooth groove of the cutter roll and does not interfere with cutting, and after cutting, each pin rises from the tooth groove, resulting in a pellet (P) formed by cutting.
) is configured to be separated from the teeth of the cutter roll. In Figure 3, the cutter roll (3) has neck parts (33) on both sides supported by bearings (6), and is rotated by gears or Transmission means such as sprockets (
34). On the other hand, as shown in FIG. 4, an eccentric boss (5) is attached to the frame (7), and the cage roll (4) rotates around the eccentric axis of the eccentric boss. In the illustrated example, an endless metal belt (2) supported by a set of rolls (21a, 21b) is used as a means for cooling and transporting the strands of sticky material;
A means for blowing cooling air or a means for spraying cooling water (8), the latter in the illustrated example, is added to this endless belt, and the cooling capacity can be varied over a wide range. This is a preferred embodiment. In addition to the endless belt, the large diameter roll used in Zaki's invention can also be used as the cooling transfer means.
In this case, cooling can also be performed by providing a cooling water flow path inside the roll. The pin (41) of the cage roll has a circular cross section in the example shown in Fig. 5, but if it is made to have a semicylindrical cross section as shown in Fig. 6, it will fit deeply into the tooth groove of the cutter roll and will not displace the pellets. It is preferable that the knockout is performed by plane contact.

[For use]

When the pitch is extruded in the form of a strand from a melt extrusion means such as an extruder and is transported while being cooled on the endless belt (2), as shown in Fig. 5, it moves in sync with the movement of the endless belt. The teeth (3) of the rotating cutter roll (3)
1) cuts the strand (S) into pellets (P) that are approximately trapezoidal when viewed from the side. At this time, if the adhesive force of the pitch is strong, the pellet will fall into the cutter roll teeth (31).
remains attached to. The pitch strand is cooled on an endless belt with a cross-sectional shape as shown in FIG. The area in contact with the belt is strongly cooled, so the lower part solidifies, and the upper surface is cooled by the surrounding air and solidifies, but the inside remains unsolidified, as shown by diagonal lines in Figure 6. The unsolidified area, which is scattered with dots, is wrapped around the solidified area shown. When extruding a strand with a relatively large diameter, or when increasing the extrusion amount and increasing the moving speed of the endless belt in order to increase the production rate, the unsolidified portion in the strand cross section may become large even if cooling is strengthened. This increases the possibility that the pellets will stick to the teeth when cutting with the cutter roll. However, since the unsolidified portion in contact with the teeth is immediately cooled and solidified by the teeth, when the pins (41) move in the radial direction and knock out the pellets, they easily fall off and fall into the pellet collection box (9). ). It will be easily understood from the above explanation that the upper part of the pellet that the pin comes into contact with has already solidified and there is no fear that the pellet and pin will stick together. In this way, there is no need to closely control the degree of cooling in cutting the pitch strands, making the operation easier. [Example] A pelletizing device having the structure shown in FIGS. 1 to 4 was manufactured. The strand die (1) has 11 nozzles with a nozzle diameter of 4.0 mm, and the endless belt (2) is made of stainless steel and has an effective cooling width of 1 m and an effective cooling length of 2 m. The cutter roll (3) has a tooth groove depth of 6.0 m, a tooth interval of 5.23 m, a diameter (outer diameter of the bottom of the tooth groove > 48.0 m), and is made of steel wire with a diameter of 2.5712111 mm. A cage roll (4) with 36 pins integrated into a cage shape and a diameter of 52° at the center was assembled with an eccentricity of the axis of 1°5M. Petroleum with a melting point of 230°C and a specific gravity of 1.2. system pitch, supply pressure 1
Discharged from the above nozzle onto the endless belt at a supply temperature of 300°C and a belt movement speed of 2 to 37F1/crA.
The cutter roll and cage roll were rotated at a speed synchronous with the belt. The endless belt was cooled by spraying cooling water from the back side. Pelletization can be carried out within the range of belt movement speeds mentioned above without any problems, and pellets with a regular shape of about 5 m in width x about 2 m in height x about 5 m in length can be formed at a speed of up to about 3 ONy/hour. It was possible to produce it. The generation of pitch powder was hardly observed. [Effects of the Invention] By using the apparatus of the present invention, highly sticky substances such as petroleum pitch and coal pitch can be pelletized without any trouble. Since there is no need to strictly control the state of pitch melting and solidification, it is possible to easily find suitable operating conditions even if the physical properties of pitch change or the pellet size is changed, resulting in high productivity. With this, 1q of pellets with a uniform shape and size are obtained. Since the generation of powder is substantially avoided, it is possible to increase the raw material yield and maintain a good working environment.

[Brief explanation of the drawing]

1 and 2 show an example of an apparatus for pelletizing pitch according to the present invention, and FIG. 1 is a plan view, and FIG.
The figure is a side view. Figures 3 and 4 show the structure of the main parts of the above-mentioned device, with Figure 3 being a longitudinal cross-sectional view of the cutter roll and cage roll, and Figure 4 being at the 1-I position in Figure 3. FIG. FIG. 5 is for explaining the operation of this device, and corresponds to a cross-sectional view taken along the line 1--2 in FIG. 3. FIG. 6 is a cross-sectional view similar to FIG. 5, showing another aspect of the cross-sectional shape of the pin of the cage roll. FIG. 7 is a schematic cross-sectional view illustrating the solidification state of a selland produced by melting and extruding a sticky substance. 1... Strand die 5... Eccentric boss 2...
・Endless belt 6... Bear link 3... Cutter roll 7... Frame 31... Teeth
8... Cooling water spraying means 32... Bottom of tooth groove S... Strand 4... Cage roll P... Pellet 41... Pin Patent applicant Kasamatsu Chemical Research Institute Co., Ltd.

Claims (2)

[Claims] (1) A means for extruding a molten sticky substance in the form of a strand, a means for receiving and transferring the extruded strand of the sticky substance while cooling it, and a means for cutting the transferred strand into pellets. In a device for pelletizing a sticky substance, which consists of a cutter roll with a large number of teeth protruding in the radial direction, a large number of parallel pins are arranged in a cage shape with a pitch synchronized with the teeth of the cutter roll. A cage roll with an outer diameter larger than the bottom of the tooth groove of the cutter roll is provided with its axis parallel to the axis of the cutter roll but slightly eccentrically upward, and the cage roll is rotated as the cutter roll rotates. When the teeth of the cutter roll cut the strand of the sticky substance, each pin of the cage roll is at the bottom of the tooth groove of the cutter roll and does not interfere with cutting, and after cutting, each pin of the cage roll A device characterized in that the device is configured to float up from the groove and separate the pellet formed by cutting from the teeth of the cutter roll. (2) The means for transporting the strands of the sticky substance while cooling it is a metal endless belt supported by a set of rolls, and the means for blowing cooling air onto the endless belt or cooling it. 2. Apparatus according to claim 1, further comprising means for spraying water.