JP2661861B2 - Extruder cylinder heating method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating method and a heating apparatus for heating a cylinder of an extruder in which a resin is melted, kneaded, molded and extruded in a cylinder having a rectangular outer edge in cross section.

[0002]

2. Description of the Related Art FIG. 4 is a schematic perspective view of a conventional heating device having a cooling fan 76 according to an embodiment.

Conventionally, a screw-type extruder generally comprises a cylinder 1 shown in FIG. 2, a screw rotated in the cylinder 1, a hopper 9 for supplying a resin material 11 to the cylinder 1, and a tip of the cylinder 1. And a heater for driving the screw, a motor for melting and gelling the resin inside at the outer peripheral portion of the cylinder, a temperature control device for the cylinder 1, and the like. Conventionally, various heating methods have been adopted. If you need a lot of heat,
An induction heating type is used instead of a resistance heating type such as an aluminum cast heater, a brass cast heater, and a band heater. In the induction heating method, when the cross section of the cylinder 1 is circular, a coil is wound around the cylinder 1 in the form of a solenoid and AC power is supplied to generate an eddy current in the cylinder 1.
We use this heat.

[0004] Therefore, in the case of a twin-screw extruder having a cylinder 1 having a rectangular outer edge in cross section, a flat heater coil is used in order to prevent imbalance in the alternating magnetic flux. However, in the case of this method, since the temperature of the heater coil tends to rise, it is necessary to take measures to prevent the temperature below the allowable temperature.Therefore, by providing a jacket for flowing a cooling fluid or providing a cooling fan 76,
In some cases, a method of cooling the coil was employed.

[0005]

However, the above-described method of cooling the coil by the jacket or the cooling fan is not preferable because the size of the apparatus is increased and the equipment cost and operation cost are increased. Therefore, an object of the present invention is to provide a heat insulating material to prevent heat transfer from the cylinder to the heater coil,
By providing a cylinder temperature automatic adjustment mechanism and a heater coil temperature automatic alarm mechanism, it is possible to maintain the cylinder temperature within a predetermined range and to maintain the coil temperature below a predetermined temperature. The object of the present invention is to provide a heating method and a heating device for a machine cylinder.

[0006]

According to the method of heating a cylinder of an extruder of the present invention, the temperature inside the cylinder is measured, and the supply current to an induction heating device having a heater coil is controlled based on the measured value. Thereby, the temperature of the cylinder is maintained within a predetermined range, the heat transfer from the heated cylinder to the heater coil is cut off, and the temperature of the surface of the heater coil is measured. The method is characterized by including a method of maintaining the temperature of the heater coil at a predetermined temperature or less by controlling the current supplied to the heater coil.

The heating device for the cylinder of the extruder includes a heat insulating material for preventing heat transfer from the heated cylinder to the heater coil, an electromagnetic controller for supplying current to an induction heating device having the heater coil, A temperature measuring element for measuring the temperature inside the cylinder, a temperature controller for transmitting a control signal for a current supplied to the induction heating device to the electromagnetic controller based on the measured value, and a temperature for the surface of the heater coil. A thermometer,
An alarm device for transmitting a control signal of a supply current to the induction heating device to the electromagnetic controller based on the measured value, and the temperature of the cylinder is maintained within a predetermined temperature range by these devices; Can be maintained below a predetermined temperature.

[0008]

The temperature inside the cylinder block is measured by a temperature measuring element. If the measured temperature falls outside a predetermined range, a control signal is transmitted from the temperature controller to the electromagnetic controller, and the temperature of the heater coil of the induction heating device is increased. The amount of heating is adjusted by adjusting the current. As a result, the operating temperature of the cylinder block quickly returns to within the predetermined range.

Further, the heat of the cylinder block, which generates heat due to the induction, is not transmitted to the heater coil of the induction heating device disposed outside the cylinder block by the heat insulating material. However, the self-heating of the heater coil is measured by measuring the temperature on the surface of the heater coil with a temperature measuring element, and when the measured temperature reaches a set point, a control signal such as a weight reduction or cutoff is transmitted from the alarm to the electromagnetic controller. The supply current to the induction heating device is controlled.

As a result, the working temperature of the cylinder is maintained within a predetermined range, and the temperature of the heater coil is also maintained at a predetermined value or less.

[0011]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1A is a schematic perspective view of a cylinder block B and an induction heating device H of one embodiment of a cylinder heating device of an extruder according to the present invention, and FIG. 2, FIG. 2 is a schematic diagram showing a heating control method of the present embodiment, and FIG. 3 is a graph showing transition of the temperature of the cylinder and the coil of the present embodiment.

[0013] The heating device for the cylinder of the extruder of the present invention comprises:
An eddy current is induced in the cylinder 1 having a structure in which the resin raw material 11 supplied into the cylinder 1 whose outer edge of the cross section has a square shape is heated and pressurized, melted and kneaded, and extruded from the molding die 10. For this reason, a flat heater coil 3 provided near the outer surface of the cylinder 1 and to which a high-frequency current is applied is provided.

The cylinder 1 is of a biaxial type and is arranged horizontally as is apparent from FIGS. 1 (a), 1 (b) and FIG. A hopper 9 for receiving the resin material 11 is provided at the left end of the cylinder 1, and a molding die 10 for extruding a plastic molded product is provided at the right end. The cylinder 1 is composed of eight cylinder blocks B _{1 to} B _{8 having} substantially the same length, and is provided with induction heating devices H _{1 to} H ₉ together with the forming die 10.

The induction heating device H is shown in FIG.
Flat heater coils 3 on the right, upper, left, and lower sides
₁ , 3_Two , 3_Three , 3_Four Are arranged, and these four heater cores
Il 3 ₁ ~ 3_Four Are connected two by two₁ , 3_Two When
3_Three , 3_Four It has become. These two sets of each heater coil
3₁ , 3_Two , And 3_Three , 3_Four Is two L-shaped coils
Support plate 4₁ , 4_Two Each is supported inside.
And the coil support plate 4₁Coils passing inward through
With the lead wires 22, 23, 24, 25, the heater coil 3
₁ And 3_Two Connection between heater coil 3₁ , 3_Two And electromagnetic
Connections between controllers 2 are made. Heater coil 3_Three ,
3_Four And the corresponding electromagnetic controller 2 'is described above.
Since they are completely the same, illustration and description are omitted.

The cylinder 1 includes a cylinder block B, and the induction heating device H, a heat insulating material 7 surrounding the periphery since heat from the cylinder block B to the heater coil 3 ₁ to 3 ₄ is prevented from being transmitted, the cylinder thermocouple 5 ₀ for measuring the temperature inside the cylinder internal temperature detection point 1a of the block B, the heater coil 3 ₁ to the solenoid control unit 2 receives the measured value
3 and temperature controller 6 for controlling the current supplied to the _4, receives the thermocouple 5 ₁ to 5 ₄ for measuring the temperature of the heater coil 3 ₁ to 3 ₄ coil surface temperature detecting points 3a, the measurement electromagnetic from the controller 2 and alarm 8 for controlling the current supplied to the coil 3 ₁ to 3 ₄ are provided with the temperature predetermined range, for example 220 ° C. ~ of the cylinder 1 by these working cylinders inside temperature detection point 1a Maintained within the range of 250 ° C., and
Heater coil 3 ₁ to 3 ₄ temperature reaches a predetermined temperature, for example 17
It is set so that it can be maintained at 0 ° C. or lower.

This is because the molding operation temperature is 220 to 250 ° C.
In addition, the allowable temperature of the litz wire serving as the heater coil is 180 ° C., and the desired use temperature is 170 ° C.

The temperature of the cylinder surface temperature detection point 1b is also measured by a thermocouple (not shown), and the measured values of the temperature of the cylinder internal temperature detection point 1a of the cylinder 1 and the temperature of the heater coil surface temperature detection point 3a are obtained. This is used as reference data for management. This measurement data is also stored in the electromagnetic controller 2
It is also possible to dispose them so as to combine them.

A similar configuration has been representatively described for the cylinder blocks B _{1 to} B ₈ and the molding die 10.

Next, the operation of the present embodiment will be briefly described because it is considered that the operation of the above-mentioned equipment is almost clear due to the configuration of the equipment.

The resin raw material 11 supplied from the hopper 9 is
An upstream cylinder block inserted into the cylinder 1 of the extruder
B₁ Block B downstream from₈ Melting before reaching,
Kneaded, molded from the molding die 10 and extruded
However, this cylinder block B ₁ ~ B₈ And molding die
The operation for keeping the temperature of b10 within the predetermined range is as follows.
It is.

The temperature controller 6 controls the cylinder block B
Is set to, for example, 180 to 220 ° C. Thermocouple temperature inside 1a of the cylinder block B 5 ₀
In measured, if the temperature control signal to the electromagnetic control device 2 is transmitted from the temperature controller 6 Once out of the set range, where, by adjusting the heater current of the coil 3 ₁ to 3 ₄ of the induction heating device H The amount of heating is adjusted. As a result, the working temperature of the cylinder block B quickly returns to within a predetermined range. Therefore, it is maintained within a predetermined temperature range.

The heater coil 3₁ ~ 3_Four Coil wire
The allowable temperature of the litz wire is 180 ° C.
The temperature is maintained at 170 ° C. or lower. To dielectric
The heat of the cylinder block B, which generates more heat, is
Heater coil 3 ₁ ~ 3_Four Don't be transmitted to
No. However, the heater coil 3₁ ~ 3_Four Is self-heating
Since the temperature rises, the temperature of the coil surface temperature detection point 3a
Thermocouple 5₁ ~ 5_Four Measured if reached 170 ° C
Then, a control signal is transmitted from the alarm 8 to the electromagnetic controller 2,
Heater coil 3₁ ~ 3_Four Reduce the current to or
Cut off. This keeps the coil temperature below 170 ° C.
It is.

The above operation can be performed individually in each of the cylinder blocks B _{1 to} B _{8, the} forming die 10 and each of the induction heating devices H _{1 to} H ₉ as necessary.

FIG. 3 is a graph showing a state where these temperatures are controlled mainly at the time of starting heating. Thus, proper and stable operation can be obtained.

[0026]

As described above, according to the present invention, a heat insulating material is provided on the outer surface of a cylinder of an extruder, and a signal for controlling an electric current supplied to a heater coil when the temperature inside the cylinder is out of a predetermined range is electromagnetically transmitted. By providing a temperature controller that transmits to the controller and an alarm that transmits to the electromagnetic controller a signal that controls the current supplied to the heater coil when the temperature of the heater coil exceeds a predetermined temperature, the temperature inside the cylinder can be reduced. Heating of the cylinder of the extruder, which can be maintained within a predetermined temperature range, the temperature of the heater coil can be maintained at or below the predetermined temperature, and the installation of large equipment for other cooling methods is unnecessary. There is an effect that the device can be provided.

[Brief description of the drawings]

FIG. 1A is a schematic perspective view of a cylinder block B of an embodiment of a cylinder heating device of an extruder according to the present invention and an induction heating device H thereof, and FIG. It is a perspective view shown typically.

FIG. 2 is a schematic diagram illustrating a heating control method according to the present embodiment.

FIG. 3 is a graph showing changes in the temperature of a cylinder and a coil according to the present embodiment.

FIG. 4 is a schematic perspective view of a conventional heating device having a cooling fan according to an embodiment.

[Description of Reference Numerals] 1 cylinder 1a, 1a ₁ to 1A ₉ cylinder internal temperature detecting points 1b, 1b ₁ ~1b ₉ cylinder surface temperature detecting points 2,2 ', 2 ₁ to 2 ₉ solenoid controller 3, 3 _1, 3 _{2, 3} 3, 3 _4, 53 heater coil 3a, 3a ₁ to 3 A ₉ coil surface temperature detection point 4 _1, 4 ₂ coil supporting plate 5 _0, 5 _1, 5 _2, 5 _3, 5 _4, 55 temperature sensing element (Thermocouple) 6 Temperature controller 7,57 Insulation material 8,8 ₁ -8 ₉ Alarm 9 Hopper 10 Molding die 11 Resin raw material 22-25,72,75 Coil lead 76 Cooling fan 77 Air passage 78 Air B , B _{1 to} B ₈ , B ₅₁ Cylinder block H, H _{1 to} H ₉ , H ₅₁ induction heating device S power supply

Claims (2)

(57) [Claims] Cylinder (1) having a rectangular outer edge in cross section
In order to induce an eddy current in the cylinder (1) of the extruder having a structure in which the resin supplied into the extruder is heated, pressurized, melted, kneaded, and extruded from the molding die (10), the cylinder ( 1) The method for heating a cylinder of an extruder by an induction heating device (H) having a flat heater coil (3) provided near an outer surface and applied with a high-frequency current, wherein the temperature inside a cylinder of a cylinder block (B) is increased. Detection point (1
The temperature of the cylinder block (B) is maintained within a predetermined range by measuring the temperature of a) and controlling the supply current to the induction heating device (H) based on the measured value, and The heat transfer from the cylinder block (B) to the heater coil (3) is interrupted, and the temperature of the coil surface temperature detection point (3a) of the heater coil (3) is measured, and based on the measured value, A method of heating a cylinder of an extruder, comprising a method of controlling a current supplied to the induction heating device (H) to maintain a temperature of the heater coil (3) at a predetermined temperature or lower. 2. A cylinder (1) having a rectangular outer edge in cross section.
In order to induce an eddy current in the cylinder (1) of the extruder having a structure in which the resin supplied into the extruder is heated, pressurized, melted, kneaded, and extruded from the molding die (10), the cylinder ( In the heating device for the cylinder of the extruder by the induction heating device (H) having the flat heater coil (3) provided near the outer surface of the above (1) and to which a high-frequency current is applied, from the heated cylinder block (B) A heat insulator (7) for preventing heat transfer to the heater coil (3), and an electromagnetic controller (2) for supplying current to the induction heating device (H)
If, temperature element for measuring the temperature of the cylinder internal temperature detection points of the cylinder block (B) (1a) and (5 _0), the supply current of the to the induction heating-up Reel (H) based on the measurement value temperature controller for transmitting a control signal electromagnetic controller to (2) and (6), said temperature sensing element to measure the temperature of the coil surface temperature detection points of the heater coil (3) (3a) (5 1 ~5 4)
And an alarm (8) for transmitting a control signal of a current supplied to the induction heating device (H) to the electromagnetic controller (2) based on the measured value. A heating device for a cylinder of an extruder, wherein the temperature of (1) is maintained within a predetermined temperature range, and the temperature of the heater coil (3) can be maintained at or below a predetermined temperature.