JPS62199423A - Vent-up reventing apparatus of vent extruder - Google Patents

Abstract

PURPOSE:To enable continuous extrusion molding without closing a vent hole, by providing a specific cylinder mechanism for pushing in a molten material, when said material is about to flow out, to the vent hole for sucking and removing a volatile component from the molten material. CONSTITUTION:A cylindrical body 6 having a vent hole 7 is provided to the cylinder 2C of a degassing part C and a push-in member 9 protruding up to the vicinity of the screw C is further provided in the cylindrical body 6 in a freely reciprocating manner so as to close the vent hole 7. If a molten material is flooded into the cylindrical body 6, by falling the push-in member 9, the molten material can be pushed back into the cylinder 2C to be prevented from stagnating in the cylindrical body 6. The surface of the molten material is always renewed to enable the promotion of degassing and, because the vent hole 7 is opened after the molten material was pushed back by the reciprocating movement of the push-in member 9, venting action is subjected to no trouble.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a vent-up prevention device for a vent extruder capable of degassing materials.

(Prior art) In extruders used for mixing, granulating, molding, etc. of plastics, rubber, etc., a pend type extruder is used that applies negative pressure inside the cylinder halfway to remove moisture and volatile matter from the material. There is something.

This vent extruder has a first measuring section in front of the material supply section, a second measuring section in front of the extrusion section, and first and second measuring sections.
A degassing section is formed between the measuring sections. Materials such as plastic or rubber, which are input from the material input port of the material supply section, and additives and fillers added to them are filled into the shallow groove of the screw of the material supply section, heated and kneaded, and then transferred to the degassing section. While being pushed by the deep groove screw, volatile matter and moisture in the molten material are gasified by negative pressure and removed to the outside of the cylinder. The salted material fills the groove of the screw in the second measuring section and is heated and kneaded until it reaches the required kneading state.

In such a vent extruder, the grooves of the screws in the first and second measuring sections are filled with the molten material with the degassing section in between.
The vent must be sealed from both sides.

However, since the screws in the first and second measuring sections are in full flight and have different groove depths, and the degree of kneading of the materials also differs, it is extremely difficult to balance the conveying capacity.
If the conveying capacity of the first measuring section is smaller than that of the second measuring section, the second measuring section will be in a material starvation state, and the pressure will fluctuate.
The amount of material extruded may fluctuate, and if the conveyance capacity of the first measuring section is larger than that of the second measuring section, material will accumulate in the screw of the degassing section, and this material will be inside the cylinder connected to the cylinder. This causes a vent-up phenomenon and eventually blocks the deaeration port formed in the cylinder, resulting in a situation where the vented-up material is not renewed.

Such material vent-up also occurs due to differences in operating conditions and materials, and there are many factors that are difficult to resolve simply by improving the shape of the screw.

Therefore, in the past, as shown in FIG.

As shown in Japanese Patent Publication No. 2911), an inner cylinder 18 is arranged with a gap 17 in the cylinder 6 connected to the cylinder 2, and even if the vent-up material 15 rises into the inner cylinder 18, the cylinder 6 The structure is such that the deaeration lower formed in the air is not blocked.

(Problems to be Solved by the Invention) In the conventional device described above, the blockage of the deaeration lower can be prevented, but the material 15 that has risen into the inner cylinder 18 is
Therefore, the surface of the vent-up material 15 is not renewed, the deaeration ability is reduced, and the progress of the vent-up phenomenon eventually blocks the deaeration lower, so there is no fundamental solution. It's hard to hope for.

(Means for Solving the Problems) The present invention provides a structure in which a pushing member is reciprocatably provided in a cylindrical body connected to a cylinder so that the bend-up material can be pushed back into the cylinder. It was designed to solve all the problems of the technology.

That is, the specific structure of the problem-solving means of the present invention is characterized by providing a cylinder between the first measuring section and the second measuring section with a cylindrical body that communicates with the inside, and a peripheral wall of this cylindrical body having a In the vented extruder with an air port formed therein, a pushing member is reciprocatably provided in the cylinder body to close the deaeration port and advance to the vicinity of the screw in the cylinder.

(Function) In the deaeration part C between the first and second measuring parts B and D, negative pressure is applied from the deaeration lower of the cylindrical body 6 connected to the cylinder 2C to melt the melt passing through the deaeration part C. Volatile matter and moisture are gasified and removed by suction from the material. When the material vents up into the cylinder 6, the air cylinder 10 is operated to lower the pushing member 9, pushing the vented material 15 back into the cylinder 2C, allowing it to be transported to the second measuring section. Make it. After that, the pushing member 9 rises and opens the closed degassing lower,
Enables gas suction to be resumed.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

In Fig. 1, reference numeral 1 denotes an l-screw extruder, in which a screw shaft 3 is rotatably inserted into a cylinder 2, and along the axial direction are a material supply section A, a first measuring section B, a degassing section C1, and a screw shaft 3. Two measuring parts and an extrusion part E are formed.

A material input port 4 is formed in the cylinder 2A of the material supply section A to input materials such as plastic or rubber, additives, fillers, etc., and a relatively deep groove is formed in the screw 3A.

1st. Band heaters 5B and 50 are provided in the cylinders 2B and 20 in the second measuring parts B and D, and heat medium circulation jackets are appropriately formed, and the grooves of the screws 3B in the first measuring part B are shallow and The groove of the screw 3D in the portion is formed deeper than the first measuring portion B.

The degassing section C is arranged between the first and second measuring sections B and D, and a cylindrical body 6 is provided at the upper part of the cylinder 2C. The cylindrical body 6 has an axis in the vertical direction, and a degassing pipe 8 connected to a vacuum device (not shown) is provided at the degassing lower part.

A piston-shaped pushing member 9 is slidably inserted into the cylinder 6. 10 is an air cylinder provided on the lid 11 at the top of the cylinder 6, and its piston rod 12
The pushing member 9 is attached to the lower part of the pushing member 9, and the pushing member 9 can reciprocate up and down by the operation of the air cylinder 10. A seal 13 closes the gap between the lid 11 and the piston rod 12.

The pushing member 9 can pass from above the deaeration lower and advance to the vicinity of the screw 3C, and when it is above the deaeration lower, it opens the deaeration lower, and when it is below it, it closes the deaeration lower. The lower surface 9a of the pushing member 9 is an arcuate surface so as to substantially follow the bore 14 of the cylinder 2C during advancement.

As shown in FIG. 2, when the pushing member 9 is retracted to a position above the deaeration lower, negative pressure is applied to the inside of the cylindrical body 6 and the cylinder 2C via the deaeration lower, and the inside of the cylinder 2C is The volatile matter and moisture inside the molten material being transported is gasified and taken out and removed.

Material conveyance capacity of the first and second weighing sections B and D 2. Prevents unbalance from occurring for some reason, reducing the capacity of the second weighing section, or causing starvation in the second weighing section. Therefore, if the conveyance capacity of the first measuring section B is set high in advance, a negative pressure action is also added, and the material will vent up into the cylinder body 6.

When the vent-up phenomenon occurs, the air cylinder 10 is actuated to advance the pushing member 9 toward the screw 3C and push the vent-up material 15 back into the cylinder 2C. This pushed back material enters the groove of the screw 3c and is conveyed to the second measuring section together with the material being conveyed, where it is subjected to a heating and kneading action. The actuation of the pushing member 9 increases the material conveyance capacity of the second metering section.

After pushing back the material, the pushing member 9 retreats upward, opening the degassing lower and restarting the degassing action. Thereafter, the vent-up phenomenon is repeated, but the vent-up material 15 is always updated to a new material.

The air cylinder 10 is provided with a limit switch that sets the upper and lower limit positions of the pushing member 9, and also sets the operation timing of the air cylinder 10 and prevents the vent-up material 15 from entering the degassing lower. Either a vent-up material detection switch is provided on the cylindrical body 6, or the air cylinder 1o is operated at a cycle shorter than the time required for the vent-up material to reach the deaeration lower. Incidentally, the operating frequency of the air cylinder 1o in this case is adjusted by a speed controller.

The means for reciprocating the pushing member 9 is not limited to an air cylinder, but may also be a hydraulic cylinder or a mechanical mechanism.

(Effects of the Invention) According to the present invention detailed above, the cylinder 2C of the deaeration section C
A pushing member 9 that closes the deaeration lower and advances to the vicinity of the screw 3C is reciprocably provided in the cylinder 6 connected to the cylinder 6 with a deaeration lower. Even if the vent-up material 15 is vented up, the vent-up material 15 can be pushed back into the cylinder 2C by the advancing operation of the pushing member 9, and the vent-up material 15 is not accumulated in the cylinder 6, and the material surface is always maintained. Moreover, the pushing member 9 reciprocates to open the deaeration lower by moving back after pushing back the material, so that the deaeration action is not hindered.

[Brief explanation of drawings]

Figures 1 to 3 show an embodiment of the present invention, where Figure 1 is a front cross-sectional view of the whole, Figures 2 and 3 correspond to a cross section taken along the line ■-■ in Figure 1, and Figure 2 is a vent-up view. Cross-sectional view showing the time of occurrence, 3rd
The figure is a cross-sectional view showing when the bent-up material is being pushed back, and FIG. 4 is a cross-sectional view of a conventional device. DESCRIPTION OF SYMBOLS 1... Extruder, 2... Cylinder, 3...-Screw shaft, 6... Cylindrical body, 7... Deaeration port, 9... Pushing member, 1o... Air cylinder, 15 ... Vent-up material, A... Supply section, B... First measuring section, C...
Deaeration section, D...second measuring section, E...extrusion section.

Claims (1)

[Claims] (1) In a vent extruder in which a cylinder between a first measuring part and a second measuring part is provided with a cylindrical body that communicates with the inside, and a deaeration port is formed in the peripheral wall of the cylinder, there is a deaeration port in the cylinder. A vent-up prevention device for a vent extruder, characterized in that a pushing member that closes an air port and advances to the vicinity of a screw in a cylinder is provided in a reciprocating manner.