JPH10305477A - Method for control of barrel temperature of double-screw extruding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a raw material from being thermally decomposed even though its operation is continued for a long time by a method wherein a temperature detection device is provided respectively to an upper side and a lower side of a barrel in each temperature control area, and an upper half and a lower half of the barrel are separately controlled in temperature. SOLUTION: A barrel 20 is divided into a plurality of temperature control areas C1 , C2 , C3 , C4 from a raw material supply opening 22 to a discharge opening 23. Then, heaters 24 to 27 is respectively provided to a barrel upper side of each area, and heaters 28 to 31 is respectively provided to a barrel lower side of each area. Further, thermo-couples 32 to 35 for detecting upper half temperature, and thermo-couples 36 to 39 for detecting lower half temperature are provided. Then, for example, only the C1 wherein a temperature difference between up and down becomes maximum is controlled in temperature separately for up and down, and the other area C2 to C4 are controlled in temperature by control of the upper side equipped with a heater capable of being controlled by cooling in which water passes through a cooling pipe. Consequently, though operated for a long time, thermal decomposition does not occur, and deteriorated matter is not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature control method for separately controlling the upper half and the lower half of a barrel of a twin screw extruder having different rotations.

[0002]

2. Description of the Related Art A twin-screw extruder of different rotation is used for kneading and melting raw materials which are easily thermally decomposed, such as PVC, and as shown in FIG.
Barrel 4 having a plurality of temperature control zones C ₁ , C ₂ ,
C _3, is divided into C _4, provided with a heater 5, 6, 7 and 8 on the outer surface of each barrel 4 in each zone, the upper, or the temperature of the thermocouple 9, 10, 11, 12, etc. on the lower side A detecting device is provided, and the temperature is set to such a degree that the raw material supplied into the barrel 4 is not thermally decomposed, and molding has been performed.

[0003]

However, even if the temperature is set so as not to cause thermal decomposition of the raw material, if the operation is continued for a long period of time, degraded substances are generated by the thermal decomposition and mixed into the molded product to obtain quality. Led to a decline.

As a result of various tests conducted by the inventors, as shown in FIG. 5, the temperature is different between the upper side and the lower side of the barrel. In the temperature control section C ₁ below the raw material supply port 2, the lower side temperature becomes 75 MIN after the start of operation. 31 above the upper temperature ^. C also got higher. For this reason, it has been found that if the operation is continued for a long time, the raw material in contact with the portion having a temperature higher than the set temperature of the barrel is deteriorated by thermal decomposition and mixed into the molded product.

The present invention has been made in view of the above-mentioned circumstances, and separately controls the upper and lower halves of a plurality of temperature control zones of a barrel of a counter-rotating twin-screw extruder, It is an object of the present invention to provide a temperature control method in which a raw material is not thermally decomposed even if the operation is continued for a long time.

[0006]

According to the present invention, there is provided a method of controlling the temperature of a barrel of a twin screw extruder having a different direction, wherein the temperature is controlled by a heating device provided on the outer peripheral surface of the barrel. Biaxial, wherein the temperature control section is divided into a plurality of temperature control sections, and a temperature detecting device is provided on each of the upper and lower sides of the barrel in each temperature control section, and the upper half and the lower half of the barrel are separately temperature-controlled. An extruder barrel temperature control method was used.

[0007] Further, there is provided a barrel temperature control method for a twin-screw extruder, wherein the temperature control section for separately controlling the upper half and the lower half of the barrel is only the control section near the lower part of the raw material supply port.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The barrel of a twin-screw extruder having a different direction of rotation is divided into a plurality of temperature control sections, and a temperature detection device is provided in each of the temperature control sections on the upper and lower sides of the barrel, respectively. The upper and lower halves are separately temperature controlled.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. 1 and 2. Reference numeral 20 denotes a barrel of a twin-screw extruder. (Right direction) is supported by the fuselage body in a cantilever state, and is inserted rotatably in different directions from each other. The barrel 20 is divided into a plurality of temperature control sections (four sections of C ₁ , C ₂ , C ₃ and C ₄ in this embodiment) from the raw material supply port 22 to the discharge port 23 side, and each section has a barrel. Heaters 24 to 27 are provided on the upper side, heaters 28 to 31 are provided on the lower side of the barrel, and thermocouples 32 to 3 for detecting the temperature of the upper half are provided.
Thermocouples 36 to 39 for detecting temperature of 5 and lower half
Is provided.

[0010] The above-explained structure is such that a different direction twin screw extruder (oblique screw extruder manufactured by Toshiba Machine Co.) TEC-
67, a test for separately controlling the upper and lower temperatures of the present invention was performed. Test temperature controlled only C ₁ the temperature difference becomes largest in the vertical up and down separately as shown in the table shown in FIG. 3, is C ₄ to other areas C ₂ no possible cooling control the cooling pipe through which water The control was performed by the upper control with the heater attached. As a result, there was no thermal decomposition even after a long operation, and there was no deterioration.

As can be understood from the table of FIG. 3, C ₂ , C
₄ is a state in which the heater is in an OFF state during operation, a cooling control in which water passes through the cooling pipe is operated, and the lower side of the barrel is 7 to 10 from the upper side.
^. C was controlled low. The vent of C ₃ has a low degree of filling in the screw groove, the high-temperature and semi-plasticized material is to flow the underside of the barrel is estimated that the temperature of the lower side is increased.

[0012]

As described above, by separately controlling the upper temperature and lower temperature of the barrel of a twin-screw extruder of different rotation, temperature control that does not cause thermal decomposition even during long-time operation and does not cause deterioration. Became the way.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of the present invention, and is an axial sectional view of a barrel.

FIG. 2 is a sectional view taken along line AA of FIG. 1 showing one embodiment of the present invention.

FIG. 3 is a table showing test results of one example of the present invention.

FIG. 4 is a diagram showing an axial cross section of a barrel portion of a conventional twin-screw extruder.

FIG. 5 is a graph showing a temporal change in a set temperature and a detected temperature of a conventional twin-screw extruder.

[Explanation of symbols]

 Reference Signs List 20 barrel 21 screw 22 material supply port 23 discharge port 24, 25, 26, 27 heater (for upper barrel) 28, 29, 30, 31 heater (for lower barrel) 32, 33, 34, 35 thermocouple (barrel) 36, 37, 38, 39 Thermocouple (for lower barrel)

Claims (2)

[Claims] 1. A method for controlling the temperature of a barrel of a twin-screw extruder having a different direction in which a temperature is controlled by a heating device provided on an outer peripheral surface of a barrel, wherein the barrel is divided into a plurality of temperature control sections, Wherein a temperature detecting device is provided on each of the upper and lower sides of the barrel, and the upper and lower halves of the barrel are separately temperature-controlled. 2. The twin-screw extruder according to claim 1, wherein a temperature control zone for separately controlling the upper half and the lower half of the barrel is only a control zone near a lower portion of a raw material supply port. Barrel temperature control method.