JP2006110777A - Uwc apparatus pcw circulating system in uwc apparatus and pellet molding processing method using uwc apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a UWC apparatus which enables reduction of man-power work, and resulting reduction of a man-power cost, and the efficient production of pellets at a low cost. <P>SOLUTION: In the PCW circulating system in the UWC apparatus 4A for circulating pellet cooling feed water (PCW) for feeding pellets subjected to molding processing in the UWC apparatus 4A while cooling them, the PCW circulating system is equipped with an opening degree adjusting valve 23 for adjusting the flow rate of PCW and a compressed air injection part for injecting compressed air in PCW at a proper place not higher than the hole of a die 5, and an adjusting part for adjusting the injection amount of compressed air is provided to the UWC apparatus 4A. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  This invention includes a UWC device (underwater cutter) known as a pellet processing device, a PCW (pellet cooling transport water) circulation system in a UWC device that cools and transports pellets molded by the UWC device used in the UWC device, And a pellet forming method using the same.

FIG. 5 is a side view showing an example of a plastic plasticizing kneading extrusion granulator.
The plastic plasticizing kneading extrusion granulator shown in FIG. 5 includes a plastic plasticizing kneading machine 1, a gear pump 2, a molten plastic filtering device 3, and a UWC device 4 which is a pellet processing device.

  Here, the plastic plasticizing and kneading machine 1 is an apparatus for plasticizing and kneading solid plastic, and the gear pump 2 is an apparatus for extruding molten plastic to a downstream apparatus. The molten plastic filtering device 3 is a device that filters solid impurities contained in the molten plastic, and the UWC device 4 is a device that processes the molten plastic into particles (pellets).

An example of a conventional UWC device 4 is shown in FIGS.
6A is a side view of the UWC device 4, and FIG. 6B is a cross-sectional view taken along line AA in FIG. 6A. In FIG. 6, a die 5, a circulation box (water tank) 6, a tie bar 7, a movable carriage 8, and a drive machine (motor) 12 are shown. Here, the die 5 and the circulation box 6 are fastened by four tie bars 7 shown in the AA cross section.

  FIG. 7 shows a cross-sectional view (inner surface transparent view) of the UWC device shown in FIG. 6 during pellet processing. In FIG. 7, a molten plastic 9, a hole (nozzle) 10, a pellet cooling water (hereinafter referred to as PCW) 11, a driving machine (motor) 12, a cutter blade 13, a pellet 14, a coupling 15, and a cutter shaft 16 are shown. ing.

  Here, the UWC device 4 including the circulation box 6, the tie bar 7, the movable carriage 8, the drive machine (motor) 12, the cutter blade 13, the coupling 15, and the cutter shaft 16 releases the fastening by the tie bar 7. Thus, it is possible to move separately from the dice 5 by the moving carriage 8.

  FIG. 8 is a system diagram showing an example of a conventional PCW circulation system. In FIG. 8, the UWC device 4, the dehydration slit 18, the centrifugal dryer 19, the PCW tank 20, the PCW pump 21, and the three-way valve 22 are shown. The PCW is circulated in the system by the PCW pump 21.

  In this configuration, the pellets molded by the UWC device 4 are transported to the dewatering slit 18 together with PCW, separated from the PCW by the dewatering slit 18, and after removing excess water adhering by the centrifugal dryer 19, It becomes a pellet product.

Next, the operation of a conventional plastic plasticizing kneading extrusion granulator will be described.
In FIG. 5, the solid plastic is supplied to the plastic plasticizing kneader 1 and plasticized. The plasticized and melted plastic is conveyed to a gear pump 2 as a downstream device by a screw 1a built in the plastic plasticizing kneader 1. The conveyed molten plastic is transferred to the molten plastic filtering device 3 and the UWC device 4 by the gear pump 2. In the molten plastic filtering device 3, solid impurities in the molten plastic are filtered. In the UWC device 4, a pellet processing operation for processing molten plastic into particles (pellets) is performed in water.

  In FIG. 6, the die 5 is heated by a heating medium (steam, hot oil, electric heater, etc.). The UWC device 4 is fastened to a hydraulic device (not shown) by four tie bars 7 installed on the outer periphery of the die 5 and the circulation box 6.

  When the pellet forming process is not performed, the UWC device 4 can be separated from the die 5 by releasing the fastening by the tie bar 7.

  In FIG. 7, the cutter blade 13 is coupled to a cutter shaft 16, and the cutter shaft 16 is connected to the driving machine 12 via a coupling 15. The molten plastic 9 is extruded in a strand shape from a large number of holes 10 processed into the dies 5 into the PCW 11 in the circulation box 6.

  The molten plastic 9 extruded in a strand shape is cut by a cutter blade 13 rotating by a driving machine 12 and formed into a pellet 14. The pellets 14 are conveyed by the PCW pump 21 while being cooled by the PCW 11 flowing upward from the bottom of the circulation box 6, and are conveyed from the circulation box 6 to a dehydration slit (not shown).

  When the extrusion of the molten plastic 9 is stopped from the many holes 10 of the die 5, the molten plastic 9 is cooled by the PCW 11 and solidified in the holes 10 of the die 5.

  For this reason, when extrusion of the pellet 14 is resumed after the extrusion of the molten plastic 9 is stopped, the following operation is required.

(1) The UWC device is separated from the die 5, and the die 5 is sufficiently heated with a heating medium.
(2) The plastic plasticizing and kneading machine 1 and the gear pump 2 are started, and it is confirmed that the molten plastic 9 is uniformly extruded from the numerous holes 10 of the die 5.
(3) The gear pump 2 is stopped and the cutting surface of the die 5 is cleaned.
(4) The UWC device 4 is fastened to the die 5.
(5) Start the cutter motor 12 and rotate the cutter blade 13 to contact the die 5.
(6) The gear pump 2 is started and the molten plastic 9 is pushed out from the numerous holes 10 of the die 5.
(7) The PCW 11 is supplied into the circulation box 6 by the PCW pump 21.

  (6) The operations of (7) are preferably performed almost simultaneously so that the PCW 11 does not cool the die 5 and the molten plastic 9 and solidify in the numerous holes 10 of the die 5. Moreover, the restarting operation of the molding process of the pellet 14 is necessary to make the shape of the pellet 14 uniform.

  As shown in FIG. 8, the pellets 14 conveyed from the UWC device 4 by the PCW 11 are conveyed to a dehydration slit 18 through a pipe. In the dehydration slit 18, the PCW 11 and the pellet 14 are separated. Then, the pellet 14 is sent to the centrifugal dryer 19, and the water adhering to the surface excessively is centrifuged to obtain a pellet product.

  On the other hand, the PCW 11 separated by the dehydration slit 18 and the centrifugal dryer 19 falls and returns to the PCW tank 20. The PCW 11 that has returned to the PCW tank 20 filters dust in the PCW 11 with a filtration device (not shown), and is sent again to the UWC device 4 with the PCW pump 21.

  If the three-way valve 22 is installed between the PCW pump 21 and the UWC device 4 and pellet molding is not performed, the PCW 11 can be returned (bypassed) to the PCW tank 20 to separate the UWC device 4 from the die. it can.

For example, the following Patent Documents 1 and 2 are known as conventional UWC devices.
JP-A-6-182760 JP-A-10-264151

  The conventional UWC device 4 is configured as described above. When the molten plastic 9 is not extruded from the hole 10 of the die 5, the molten plastic 9 is solidified in the hole 10 of the die 5 by the PCW 11. Therefore, when the pellet forming process is resumed, the following operation described above is always necessary.

(1) The UWC device 4 is separated from the die 5 and the die 5 is sufficiently heated with a heating medium.
(2) The plastic plasticizing and kneading machine 1 and the gear pump 2 are started, and it is confirmed that the molten plastic 9 is uniformly extruded from the numerous holes 10 of the die 5.
(3) The gear pump 2 is stopped and the cutting surface of the die 5 is cleaned.
(4) The UWC device 4 is fastened to the die 5.
(5) The cutter motor 12 is started and the cutter blade 13 is rotated to contact the die 5.
(6) The gear pump 2 is started and the molten plastic 9 is pushed out from the numerous holes 10 of the die 5.
(7) The PCW 11 is supplied into the circulation box 6 by the PCW pump 21.

  Such an operation has a problem of requiring a large amount of human work and increasing the human cost. In particular, the larger the UWC device, the greater the problem.

  The present invention has been made to solve the above-described conventional problems, and can reduce the human work in the pre-operation when the pellet forming process is resumed by the above-described UWC device. It is an object of the present invention to provide a UWC apparatus that can reduce the cost, and can efficiently manufacture pellets at low cost, and a pellet processing method using the same.

  In order to solve the above-described problems, the present invention provides a pellet cooling / conveying water in a PCW circulation system in a UWC apparatus that circulates pellet cooling / conveying water (PCW) that conveys pellets molded and processed in the UWC apparatus. An opening adjustment valve for adjusting the flow rate is provided, and a compressed air injection part for injecting compressed air into the pellet cooling / conveying water is provided at an appropriate position lower than the hole of the die, and the injection amount of the compressed air is adjusted. The adjustment unit is provided in the UWC device.

  In addition, the present invention extrudes molten plastic from a hole in a die with a UWC device, cuts it with a cutter blade, and transports the cut pellet while cooling it with pellet cooling water (PCW) circulated by a PCW circulation system. In the pellet forming method using the UWC apparatus, the compressed air is injected into the pellet cooling water from a position lower than the hole of the die before restarting the pellet forming process while circulating the PCW. The temperature of the die is increased.

  In addition, the present invention extrudes molten plastic from a hole in a die with a UWC device, cuts it with a cutter blade, and transports the cut pellet while cooling it with pellet cooling water (PCW) circulated by a PCW circulation system. In the pellet forming method using the UWC apparatus, the flow rate of the pellet cooling carrier water is decreased to increase the temperature of the die before restarting the pellet forming process while circulating the PCW. It is characterized by that.

  In addition, the present invention extrudes molten plastic from a hole in a die with a UWC device, cuts it with a cutter blade, and transports the cut pellet while cooling it with pellet cooling water (PCW) circulated by a PCW circulation system. In the pellet forming method using the UWC apparatus, the pellet cooling transport water flow rate is reduced before the pellet forming process is resumed while the PCW is circulated, and the pellet cooling transport water is supplied with the die. Compressed air is injected from a position lower than the hole of the die to raise the temperature of the die.

  As described above, according to the present invention, since the temperature of the die can be raised and the plastic once solidified in the die hole can be melted again, the UWC device is separated when the pellet forming process by the UWC device is resumed. It becomes possible to implement without. Further, when pellet molding is performed by the UWC apparatus, it is possible to carry out with a small number of people and a simple operation. Therefore, according to the present invention, it is possible to reduce the human work in the preliminary operation when resuming the pellet forming process by the UWC device, thereby reducing the human cost, and efficiently and efficiently reducing the pellets. There is an effect that can be manufactured.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a system diagram showing an example of a PCW circulation system in an embodiment of the present invention, and FIG. 2 is a side view showing a UWC device. In the PCW circulation system shown in FIG. 1, a UWC device 4A, a dehydration slit 18, a centrifugal dryer 19, a PCW tank 20, a PCW pump 21, a three-way valve 22, and an opening adjustment valve are arranged along a circulation path constituted by piping. 23 is provided, and the PCW is circulated through the circulation system by the PCW pump 21.

  In the UWC device 4A in the embodiment shown in FIG. 2, a die 5 having a hole 10, a circulation box 6, a cutter motor 12, a cutter blade 13, a coupling 15, a cutter shaft 16, a flow meter 25, and a flow rate adjusting valve 26 are provided. I have. In the figure, reference numeral 24 denotes compressed air. Here, the compressed air supply pipe connection part 4c is connected to the UWC device 4A at a position lower than the die 5 of the pipe connection part 4b in the PCW circulation system. A flow meter 25 and a flow rate are connected to the compressed air supply pipe connection part 4c. The adjustment valve 26 is provided to constitute a compressed air injection unit, and the flow rate adjustment valve 26 constitutes an adjustment unit that adjusts the injection amount of compressed air.

  FIG. 3 is an operation explanatory view showing an example of the behavior of the compressed air in the circulation box 6. In FIG. 3, reference numeral 27 denotes a first air layer, and 28 denotes a second air layer.

The operation of the embodiment will be described below.
In FIG. 1, pellets molded by the UWC device 4 </ b> A are transported by the PCW 11, pass through the piping, and are transported to the dehydration slit 18. In the dehydration slit 18, the PCW 11 and the pellet 9 are separated. The pellet 9 is sent to the centrifugal dryer 19, and the water adhering to the surface excessively is centrifuged to obtain a pellet product.

  On the other hand, the PCW 11 separated by the dehydration slit 18 and the centrifugal dryer 19 falls and returns to the PCW tank 20. The PCW 11 that has returned to the PCW tank 20 filters the dust in the PCW with the filtration device 3 (see FIG. 5), and is sent again to the UWC device 4A by the PCW pump 21.

  A three-way valve 22 and an opening degree adjustment valve 23 are installed between the PCW pump 21 and the UWC device 4A. The three-way valve 22 returns the PCW 11 to the PCW tank 20 (bypass) when the cutter blade 13 built in the UWC device 4A wears and is replaced for a short time when it is replaced, and when the UWC device 4A itself is maintained. ), And the UWC device 4A is provided so as to be separated from the circulation system.

  The opening adjustment valve 23 uses the pump capacity characteristic with respect to the back pressure of the PCW pump 21, adjusts the PCW pressure in the system by adjusting the opening, and adjusts the PCW flow rate supplied to the UWC device 4A. It is provided so that it becomes possible.

  When the pellet forming process is resumed by the opening adjustment valve 23, the PCW flow rate is increased to a flow rate at which the pellet 14 can be sufficiently cooled and conveyed by opening the opening adjustment valve 23, and the molten plastic 9 is extruded from the die 5. If not, the opening adjustment valve 23 is closed, and the PCW flow rate can be reduced.

  In FIG. 2, the die 5 is heated by a heating medium (steam, hot oil, electric heater, etc.). The UWC device 4A is fastened to a hydraulic device (not shown) with four tie bars (see FIG. 6B) installed on the outer periphery of the die 5 and the circulation box 6.

The cutter blade 13 is coupled to a cutter shaft 16, and the cutter shaft 16 is connected to the drive machine 12 via a coupling 15.
The molten plastic 9 is extruded into a PCW 11 in the circulation box 6 in a strand shape from a large number of holes 10 processed into the die 5. The molten plastic 9 extruded in a strand shape is cut by a cutter blade 13 rotated by a driving machine 12 and molded into a pellet 14.

  The pellets 14 are cooled and conveyed by the PCW pump 21 (not shown) by the PCW 11 flowing from the bottom to the top of the circulation box 6 and conveyed from the circulation box 6 to a dehydration slit (not shown). At this time, while checking the compressed air 24 with the flow meter 25, the injection amount is adjusted by the flow rate adjusting valve 26, and an appropriate amount is injected into the PCW 11.

  The compressed air 24 may be injected from any position lower than the hole 10 of the die 5. Moreover, the injection of the compressed air 24 starts to be supplied before restarting the pellet forming process. After confirming that the temperature of the die 5 is sufficiently increased with a thermometer (not shown) installed in the die 5, the pellet forming process is resumed.

  In FIG. 3, the compressed air 24 supplied from below the die 5 is raised by the PCW 11 flowing from the bottom to the top of the circulation box 6 by the PCW pump 21 and the specific gravity difference. The raised compressed air 24 gathers in the vicinity of the cutter blade 13 rotating by the drive machine 12 and forms a first air layer 27. In addition, the gap between the die 5 and the cutter blade 13 is rotated by the driving machine 12 (not shown), so that a pressure difference with the outside is generated, and the compressed air 24 enters, and the second An air layer 28 is formed.

  The compressed air 24 from the first air layer 27 and the second air layer 28 further rises due to the flow of the PCW 11 flowing from the bottom to the top of the circulation box 6 by the PCW pump 21 and the specific gravity difference, and to the outside of the circulation box 6. Discharged. The compressed air 24 discharged out of the circulation box 6 is discharged out of the PCW circulation system through the dewatering slit 18 of the PCW circulation system.

  The first air layer 27 and the second air layer 28 are always renewed by the compressed air that is injected. By forming the second air layer 28, the contact between the surface of the die 5 and the PCW 11 is reduced, and the temperature of the die 5 rises.

  The plastic solidified in the hole 10 of the die 5 is melted when the temperature of the die 5 rises.

  As described above, in the embodiment of the present invention, a facility for injecting compressed air into the PCW, an opening adjusting valve between the PCW pump and the UWC device in the PCW circulation system, and a compressed air in the PCW are provided. By injecting, the opportunity for the PCW to come into contact with the heated die surface can be reduced and the die temperature can be raised.

  Further, by narrowing the opening adjustment valve, the PCW pressure in the PCW circulation system increases and the PCW flow rate supplied to the circulation box decreases. The PCW takes heat from the die heated in the circulation box, and the temperature rises. When the PCW flow rate is low, the PCW temperature in the circulation box rises more than when the PCW flow rate is high. By increasing the PCW temperature, the die temperature can be kept high.

  In this way, by increasing the die temperature, the solidified plastic can be melted in the die hole, and when restarting the pellet forming process by the UWC device, the UWC device is separated, the die is heated sufficiently, and the molten resin is removed from the die. It is possible to reduce many operations such as confirming that the plastic is not solidified in the extrusion die hole, cleaning the die surface, and attaching the UWC device to the die.

  Next, the implementation results of the present invention using the above apparatus are shown below.

Raw material: Polyester plastic Die temperature: 360 ° C
Polymer temperature: 290 ° C
PCW supply temperature: 80 ° C
Extrusion speed from molten plastic die: 240 cm / s

And changing the amount of compressed air injection and the PCW flow rate, and comparing the opening rate of the die hole,
The results are summarized in FIG.

As shown in FIG. 4, by injecting compressed air, the opening ratio of the die holes increased by 2.3 times or more. By reducing the PCW flow rate, the opening rate of the die hole increased.
When the ratio of compressed air injection / PCW flow rate was large, the opening ratio of the die hole increased.

It is a systematic diagram which shows an example of the PCW circulation system in embodiment of this invention. It is a side view which shows a UWC apparatus. It is operation | movement explanatory drawing which shows an example of the behavior of the compressed air in a circulation box. It is a figure which shows the result of an Example. It is a side view showing an example of a plastic plasticizing kneading extrusion granulator. It is a figure which shows an example of the conventional UWC apparatus, FIG. 6 (A) is a side view of a UWC apparatus, FIG.6 (B) is AA sectional drawing of FIG. 6 (A). It is sectional drawing at the time of the pellet process of the UWC apparatus shown in FIG. It is a systematic diagram which shows an example of the conventional PCW circulation system.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Plastic plasticizing kneader, 2 Gear pump, 3 Molten plastic filtration apparatus, 4A UWC apparatus, 4b Pipe connection part, 4c Compressed air supply pipe connection part, 5 Dies, 6 Circulation box (water tank), 7 Tie bar, 8 Moving cart, 10 hole (nozzle), 11 pellet cooling water, 12 drive machine (motor), 13 cutter blade, 14 pellet, 15 coupling, 16 cutter shaft, 18 dehydration slit, 19 centrifugal dryer, 20 PCW tank, 21 PCW pump , 22 Three-way valve, 23 Opening adjustment valve, 24 Compressed air, 25 Flow meter, 26 Flow adjustment valve, 27 First air layer, 28 Second air layer.

Claims (4)

In a PCW circulation system in a UWC device that circulates pellet cooling transport water (PCW) that transports while cooling pellets molded in the UWC device,
An opening adjustment valve for adjusting the flow rate of the pellet cooling transport water, a compressed air injection unit for injecting compressed air into the pellet cooling transport water at a proper position lower than the hole of the die, and the compressed air The PCW circulation system characterized in that the UWC device is provided with an adjustment unit for adjusting the injection amount of. A UWC device that extrudes molten plastic from a hole in a die by a UWC device, cuts it by a cutter blade, and transports the pellets while being cooled by pellet cooling water (PCW) circulated by a PCW circulation system. In the pellet molding method using
Before restarting the pellet molding process with PCW circulating,
A pellet forming method using a UWC apparatus, wherein compressed air is injected into the pellet cooling / conveying water from a position lower than the hole of the die to raise the temperature of the die. A UWC device that extrudes molten plastic from a hole in a die by a UWC device, cuts it by a cutter blade, and transports the pellets while being cooled by pellet cooling water (PCW) circulated by a PCW circulation system. In the pellet molding method using
Before restarting the pellet molding process with PCW circulating,
A pellet forming method using a UWC device, wherein the flow rate of the pellet cooling transport water is decreased to raise the temperature of the die. A UWC device that extrudes molten plastic from a hole in a die by a UWC device, cuts it by a cutter blade, and transports the pellets while being cooled by pellet cooling water (PCW) circulated by a PCW circulation system. In the pellet molding method using
Before restarting the pellet molding process with PCW circulating,
A UWC device that reduces the flow rate of the pellet cooling transport water and injects compressed air into the pellet cooling transport water from a position lower than the hole of the die to raise the temperature of the die. The pellet forming method used.

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