JP2641158B2 - Rotary cutter position adjustment device for pelletizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary cutter position adjusting device for adjusting a separation distance of a rotary cutter from a die plate in a pelletizer for manufacturing synthetic resin pellets.

[0002]

2. Description of the Related Art An outline of a conventional pelletizer will be described with reference to FIG. A large number of extrusion holes 22 are formed in a die plate 21 provided at the end of the extruder 2 in a line in a circle, and a rotary cutter 3 is provided facing the die plate 21. The molten resin extruded toward 23 is successively cut into pellets by the rotation of the rotary cutter 3 by the rotary shaft 4. Rotary cutter 3
An appropriate cooling fluid such as water or air is circulated inside the granulation chamber 23 in which the rotating pellets rotate, and the cut pellets are cooled and solidified by touching the cooling fluid, and then taken out to the outside. The rotary cutter 3 advances and retreats with respect to the opposing surface of the die plate 21 by the feed screw 43 to adjust the separation gap. Reference numerals 6 and 42 denote a worm and a worm wheel for giving this feed rotation, respectively. Reference numeral 41 denotes a pulley that drives the rotary shaft 4 to rotate.

[0003]

In a pelletizer, the clearance (clearance) between the rotary cutter 3 and the die plate 21 is extremely important. If the clearance is too small to come into contact with each other, In particular, abrasion of the rotary cutter 3 is caused and metal powder is mixed in the pellets. If the clearance is too wide, the resin is not sheared smoothly, and burrs commonly called "whiskers" are generated in the pellets. Invite the situation. Therefore, in the pelletizer, the clearance between the rotary cutter 3 and the die plate 21 is carefully set very delicately. However, it is affected by various factors that occur during operation, for example, the temperature rise of the extruder head. Since the above-mentioned clearance fluctuates due to the thermal expansion and elongation of the rotating shaft 4, the clearance value set prior to operation cannot be maintained at a constant value without fluctuating during operation. It is. Conventionally, readjustment of the clearance is performed by measuring the distance between the rotary cutter 3 and the die plate 21 using a clearance gauge or a dial gauge. However, this clearance measurement adjustment operation is extremely complicated, and this operation is also difficult. In this case, the operation of the pelletizer must be interrupted each time, so that the operation efficiency of the pellet production can be suppressed to a low level, and the improvement of the production efficiency cannot be expected.

[0004] Attempts to improve such inconveniences have not been completely eliminated. For example, 58
The cutter blade position adjusting device disclosed in JP-A-62613 discloses a sensor that detects a change in the gap between the cutter blade and the die plate as a voltage change when facing the granulating chamber of the pelletizer, on the surface of the die plate facing the cutter blade. The drive control of the pilot motor is performed in accordance with the change in the voltage provided by the voltage detection sensor, whereby the cutter blade is automatically advanced and retracted with respect to the die plate. However, since the molten resin is always kneaded into the gap between the cutter blade and the die plate, the sensor is covered by these resins and the detection function cannot be fully exhibited, and therefore, based on the detection information of this sensor. There was a disadvantage that the position adjustment of the cutter blade became inaccurate.

[0005]

SUMMARY OF THE INVENTION The present invention provides a rotary cutter position adjusting device for a pelletizer which can always quantitatively control a clearance between a rotary cutter of a pelletizer and a die plate to a desired optimum value without causing the above-mentioned problems. Specifically, non-conductive molten resin extruded into the granulation chamber from the extrusion hole of the die plate provided at the end of the extruder, extrusion of the die plate In a pelletizer for manufacturing pellets of the resin by cutting into a pellet shape by a rotary cutter rotating close to a side end surface, the die plate is electrically grounded, and one electrode of a high-frequency AC power supply is connected to the rotary cutter. Are electrically connected to each other, and the other electrode of the high-frequency AC power supply is a kind of capacitor whose capacitance value is a digit. A rotating cutter position adjustment device in the connected comprising pelletizer clearance indicator displayed by Le amount. Also, the present invention provides the rotary cutter position adjusting device in the above-described pelletizer, wherein the voltage output device outputs a voltage corresponding to a difference between the display quantity of the clearance indicator and a predetermined reference amount, and an output voltage of the voltage output device. And a worm rotated by the motor, wherein the rotation of the worm causes the rotary cutter to move in a direction approaching or away from the die plate. It is an adjustment device.

According to the present invention, the conductive molten resin extruded from the extrusion hole of the die plate provided at the end of the extruder into the granulation chamber is rotated in proximity to the extrusion-side end face of the die plate. In a pelletizer for manufacturing the resin pellets by cutting into pellets by a rotary cutter, the die plate is electrically grounded, and one electrode of a DC power supply is electrically connected to the rotary cutter, The other electrode of the power supply is a rotary cutter position adjusting device in the pelletizer which is connected to a clearance indicator which is a kind of resistance measuring device and the measured resistance value is displayed in a digital quantity. The invention also provides
In the rotary cutter position adjusting device in the above-described pelletizer, a voltage output device that outputs a voltage corresponding to a difference between the display amount of the clearance indicator and a predetermined reference amount, and driving is controlled by an output voltage of the voltage output device. A rotary cutter position adjusting device having a motor and a worm rotated by the motor, wherein the rotary cutter moves the rotary cutter in a direction approaching or away from the die plate by rotation of the worm.

[0007]

[Function] If the operator looks at the numerical value displayed on the clearance display and manually rotates the worm so that the numerical value becomes a desired optimum value, the position of the rotary cutter of the pelletizer can be easily adjusted to the optimum position. it can. Further, in the configuration in which the voltage output device is provided, the above-described manual adjustment operation can be fully automated, and monitoring of an operator is not required.

[0008]

1 and 2 show a first embodiment of the present invention.
(A) will be described. FIG. 2A shows only the electric circuit portion of the embodiment shown in FIG. The molten resin of the pellets to be produced is extruded from the extrusion holes 22 of the die plate 21 of the extruder 2 by an extrusion screw drawn on the right side, and exits into a granulation chamber 23 cooled by an appropriate cooling medium. Where to come die plate 2
The pellets 1 are cut continuously by the rotating cutter 3 rotating close to the end face of the pellet 1 to continuously produce the pellets 1. The rotary cutter 3 is attached to an end of a rotary shaft 4 which is driven to rotate via a pulley 41. The rotary shaft 4 is rotated by a worm 6 via a worm wheel 42 so as to be integrally rotated therewith. The screw 43 is moved forward and backward in its longitudinal direction, whereby the distance of the rotary cutter 3 to the facing surface of the die plate 21, that is, the clearance in question here is adjusted.

The rotating shaft 4 is rotatably supported in an electrically insulated state from its support body by an insulating sleeve 44 made of a suitable electric insulating material.
And the granulating chamber 2 in which the rotary cutter 3 rotates to produce the pellet 1
3 is also electrically insulated by a suitable electric insulating material 7 from the wall. The die plate 21 is electrically grounded, and one end of a high-frequency AC power supply 9 is connected to the end of the rotating shaft 4 via a rotary contact 8.
The other electrode of the high-frequency AC power supply 9 is connected to one electrode plate 10A of a clearance indicator 10, which is a kind of capacitor. The other electrode plate 10B of the clearance indicator 10 is grounded via a case. Clearance indicator 10
Is a so-called electrostatic capacitance meter whose capacitance is displayed as a digital quantity so as to be easily seen by an operator.

Next, the operation of this embodiment will be described.
First, suppose that the rotary cutter 3 is in contact with the die plate 21, that is, the clearance that is a problem of the present invention is zero, and the opposing electrode plates 10A and 10B of the clearance indicator 10 are both grounded. Since they are in the same potential state, the capacitance value indicated by the clearance indicator 10 is zero. However, the rotating cutter 3 is the die plate 2
Away from 1, both act like the opposing plates of the capacitor, forming a kind of capacitor here, where a certain amount of charge is stored. This capacitance is the same as the capacitance of the clearance indicator 10 because the control electric circuit is balanced as a whole. That is, knowing the capacitance of the clearance indicator 10 allows the capacitance of the capacitor formed by the rotary cutter 3 and the die plate 21, in other words, the clearance of the molten resin interposed therebetween to be constant if the dielectric constant is constant. You can know. Therefore, if the relationship between the clearance and the capacitance value of the clearance indicator 10 is checked in advance, the size of the target clearance can be known from the capacitance value. If the clearance amount calculated from the above relationship is directly displayed instead of the capacitance value as the digital amount displayed on the clearance display 10, the clearance adjustment work becomes easier. .

The preferred clearance between the rotary cutter 3 and the die plate 21 varies slightly depending on the resin used, but is in the range of 30 to 50 μm. Therefore, the operator works while monitoring the display amount of the clearance indicator 10, and when the clearance between the rotary cutter 3 and the die plate 21 deviates from the above-mentioned desired suitable value, the worm 6 may be adjusted by hand. It is good.

The second embodiment of the present invention is the same as the first embodiment shown in FIG. 1 except that only the control electric circuit is different as shown in FIG. 2 (b). That is, in this second embodiment, the operator does not operate the worm 6 by looking at the clearance between the rotary cutter 3 and the die plate 21 shown on the clearance display 10, but the display amount of the clearance display 10 is a predetermined amount. When a difference appears as compared with the optimal clearance amount, a voltage output device 13 that generates an output voltage according to the difference is provided, and the motor 5 is driven and controlled by the output voltage output from the voltage output device 13, The worm 6 is automatically rotated by a predetermined amount in a predetermined direction by the motor 5 to adjust the clearance between the rotary cutter 3 and the die plate 21.

A third embodiment of the present invention is an apparatus having a control electric circuit applicable when the pellet resin is conductive. That is, in this case, as shown in FIG. 3A, an oscilloscope-type resistance measuring device is used as the clearance indicator 12 instead of a capacitor, for example, as shown in the figure. Further, unlike the above embodiments, a DC power supply 11 is inserted into the circuit instead of the high-frequency AC power supply.
The principle of operation of this embodiment is self-evident. If the clearance between the rotary cutter 3 and the die plate 21 increases, the electrical resistance value to be measured by the clearance indicator 12 increases in proportion to the amount. Is used. In addition, in the case of this embodiment, similarly to the above-described embodiment,
Taking into account the specific resistance that differs depending on the conductive resin used, the rotary cutter 3 and the die plate 2
The relationship between the clearance between the clearance indicators 1 and the resistance value indicated on the clearance indicator 12 is checked beforehand.
Second, it is preferable that the desired clearance amount is directly digitally displayed.

The fourth embodiment of the present invention is an apparatus used for a conductive resin similarly to the third embodiment, and the clearance adjustment is not performed manually by an operator, as shown in FIG. 3 (b). Automatically performed by the motor 5. That is, in this embodiment, a voltage output device 13 for outputting a voltage proportional to an electric resistance value between the rotary cutter 3 and the die plate 21 measured by the clearance indicator 12 is inserted into the control circuit as shown in FIG. The motor 5 is driven and controlled by the output voltage output from the container 13, and the worm 6 is automatically rotated by a predetermined amount in a predetermined direction by the motor 5 to adjust the clearance between the rotary cutter 3 and the die plate 21. Things.

[0015]

According to the apparatus of the present invention, the rotary cutter 3
The gap between the die plate 21 and the clearance indicator 10
Or, it is displayed as an easy-to-read digital value in 12, so the operator looks at the value displayed on the clearance display and manually rotates the worm 6 so that the value falls within the range of the desired optimum value. The position of the rotary cutter 3 of the pelletizer can be easily adjusted to the optimum clearance holding position. In addition, according to the configuration in which the voltage output device 13 and the motor 5 driven and controlled by the output voltage are provided, the above-described manual adjustment operation can be fully automated, and monitoring of the operator is almost unnecessary. There are advantages.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

FIG. 2A is a circuit diagram extracted and drawn from a control circuit of an embodiment of manual control used for the non-conductive resin shown in FIG. 1;
(B) is a circuit diagram of an embodiment in which a motor for automatic adjustment is similarly incorporated.

FIG. 3 (a) is a circuit diagram extracted and drawn out of a control circuit of an embodiment of manual control used for a conductive resin, and FIG. 3 (b) is a circuit diagram of an embodiment in which a motor for automatic adjustment is similarly incorporated. .

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pellet 2 Extruder 21 Die plate 22 Extrusion hole 23 Granulation chamber 3 Rotary cutter 4 Rotary shaft 5 Motor 6 Warm 10, 12 Clearance display 13 Voltage output device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toraichi Ishikawa 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric Wire Co., Ltd. (72) Inventor Hisao Sakaguchi 1-5-1, Kiba, Koto-ku, Tokyo Fujikura (56) References JP-A-50-100155 (JP, A) JP-A-2-198806 (JP, A) JP-A-58-62613 (JP, U) JP-A-62-38114 (JP, A) , U)

Claims (4)

(57) [Claims] 1. A non-conductive molten resin extruded from an extrusion hole (22) of a die plate (21) provided at an end of an extruder (2) into a granulation chamber (23). In a pelletizer for manufacturing pellets of the resin by cutting into pellets by a rotary cutter (3) rotating in proximity to an end surface on the extrusion side of the plate (21), the die plate (21) is electrically grounded and One electrode of a high-frequency AC power supply (9) is electrically connected to the rotary cutter (3), and the other electrode of the high-frequency AC power supply (9) is a kind of capacitor having a capacitance value. A rotary cutter position adjusting device in a pelletizer connected to a clearance indicator (10) for displaying a digital amount. 2. A voltage output device (13) for outputting a voltage corresponding to a difference between a display quantity of the clearance display (10) and a predetermined reference amount, and driven by an output voltage of the voltage output device (13). It has a motor (5) to be controlled and a worm (6) rotated by the motor (5), and the rotation of the worm (6) causes the rotary cutter (3) to approach the die plate (21). The rotary cutter position adjusting device for a pelletizer according to claim 1, wherein the rotary cutter position adjusting device is configured to be moved in a separating direction. 3. An electroconductive molten resin extruded from an extrusion hole (22) of a die plate (21) provided at an end of an extruder (2) into a granulation chamber (23). In a pelletizer for producing pellets of the resin by cutting into pellets by a rotary cutter (3) rotating close to the extrusion side end face of (21), the die plate (21) is electrically grounded, One electrode of a DC power supply (11) is electrically connected to the rotary cutter (3), and the other electrode of the DC power supply (11) is a kind of resistance measuring device whose measured resistance value is a digital quantity. A rotary cutter position adjusting device for a pelletizer connected to a clearance indicator (12) indicated by (1). 4. A voltage output device (13) for outputting a voltage corresponding to a difference between a display quantity of the clearance display (12) and a predetermined reference amount, and driven by an output voltage of the voltage output device (13). It has a motor (5) to be controlled and a worm (6) rotated by the motor (5), and the rotation of the worm (6) causes the rotary cutter (3) to approach the die plate (21). 4. The rotary cutter position adjusting device for a pelletizer according to claim 3, wherein the rotary cutter position adjusting device is configured to be moved in a separating direction.