JP3279499B2 - Twin screw extruder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a cylinder having a predetermined length and a screw rotatably driven in the cylinder. The present invention relates to a twin-screw extruder in which end faces are joined to each other via a sealing device and have a predetermined length.

[0002]

2. Description of the Related Art A twin-screw extruder is conventionally well-known as a single-screw extruder. A twin-screw extruder is provided with a cylinder having a predetermined length provided with an external heater, and is rotationally driven in a different direction or the same direction in the cylinder. And a screw adapted to be used. Therefore, when the inside of the cylinder is heated by a heater, the screw is driven to rotate and the resin material is fed forward while being melt-kneaded, and then extruded from the die,
Extruded products such as pipes, sheets, and films can be obtained.

[0003] Incidentally, since the cylinder is formed to have a predetermined length by joining a plurality of cylinder units at their end faces, the joined end faces need to be sealed. Since a heater is provided to heat the resin, furthermore, the resin generates heat when it is kneaded, so that a general rubber sealing material cannot be used for the joint end surfaces of the cylinder units. Therefore,
Conventionally, end faces of cylinder units are sealed by metal touch.

[0004]

As described above, the end faces of the cylinder units are sealed even though they have a metal touch, so that they can be formed temporarily. However, the quality of the molded product may be reduced due to insufficient sealing. For example, when a resin material such as polyester or nylon is heated, substances such as monomers are separated into a gaseous state, and water is separated into water vapor and separated. Become. Therefore, these gases need to be degassed, and in order to enhance the degassing effect, the inside and outside of the cylinder must be completely sealed. When the end faces of the unit are tightened with a plurality of tightening bolts, the sealing is incomplete due to the difference in the strength of each tightening force. Therefore, the deaeration effect is not sufficiently improved. The present invention has been made in view of the above-described conventional circumstances, and has a high sealing effect, regardless of the strength of the tightening force of the cylinder unit. It is an object of the present invention to provide a twin-screw extruder that can obtain the following.

[0005]

According to the present invention, in order to achieve the above object, a hollow metal ring is applied to a sealing device. Inside the hollow metal ring, an inner hole of a cylinder is provided. It is configured such that the gas pressure acts. That is, in order to achieve the above object, the present invention comprises a cylinder having a predetermined length and a screw adapted to be rotationally driven by an inner hole of the cylinder, wherein the cylinder comprises a plurality of cylinder units. A twin-screw extruder in which axial end faces are joined to each other via a sealing device to form a predetermined length, wherein the sealing device is disposed radially inward on an end face of the cylinder unit. A first hollow metal ring member, and a second hollow metal ring member disposed outside the first hollow metal ring member at a predetermined distance from the first hollow metal ring member. At a position of the hollow metal ring body facing the inner hole of the cylinder, a through-hole communicating therewith is opened, and the first,
The chambers provided with the two hollow metal ring bodies are connected by a gas chamber, and the gas chamber is configured to be filled with an inert gas.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. As shown in FIG. 1A, the twin-screw extruder according to the present embodiment also includes a cylinder 1 having a predetermined length and a different direction or the same direction within the cylinder 1 as conventionally known. And a screw 20 (20) adapted to be rotationally driven. The cylinder 1 includes a plurality of cylinder units 1 as is well known.
a, 1b,... A heater 2 is provided on the outer peripheral portion of each of the cylinder units 1a, 1b,...
3 'are integrally formed. Further, a well-known vent pipe 4 is also provided in each of the predetermined cylinder units 1c and 1f.

FIG. 1B is an enlarged view of a part of the cylinder units 1a, 1b,... Constructed as described above. Are provided with a plurality of holes for bolt insertion, and adjacent flanges 3, 3 'are tightened by a plurality of tightening bolts 6, 6,... As shown in FIG. Although it is connected and integrated, a sealing device described below is interposed on the joint surface of the flanges 3 and 3 '.

According to the present embodiment, the sealing device comprises first and second hollow metal ring bodies 10 and 12 and a gas chamber 15. That is, the joining end faces of the flanges 3 of the cylinder units 1a, 1b,.
(C), the ring-shaped first groove 13 having a predetermined depth and a predetermined width opened to the mating side to be joined.
A similar ring-shaped second groove 14 is formed concentrically outside the first groove 13 in the radial direction. Further, a part of the joint end face of the flange 3 is cut off so as to connect the first and second concave grooves 13 and 14 to form a gas chamber 15. And these first two
The first and second hollow metal ring bodies 1 are inserted into the concave grooves 13 and 14, respectively.
0 and 12 are provided respectively. The first of these,
The diameter of the hollow metal ring bodies 10 and 12 is larger than the depth of the first and second concave grooves 13 and 14 by a predetermined amount, and when the flanges 3 and 3 'are joined together, the end faces of the flanges 3 and 3' are formed. However, the size is selected such that there is a margin in the radial direction and a small gas chamber is formed in the first and second concave grooves 13 and 14.

According to the illustrated embodiment, an appropriate number of gas holes 11 are provided on the side of the first hollow metal ring body 10 facing the inner hole of the cylinder 1 or the side facing the screw 20 (20). Is provided. The gas chamber 15 and the outside of the cylinder 1 are connected by a gas supply hole 16, and an inert gas such as nitrogen gas is supplied to the gas chamber 15 from the outside at a predetermined pressure.

Next, the operation will be described. A plurality of cylinder units 1a, 1b,.
.. Are joined by tightening bolts 6, 6,. At this time, the first and second hollow metal ring bodies 10 and 12 are pushed by the joining end faces of the flanges 3 and 3 ′, and are exaggeratedly shown in FIG. It is slightly deformed into such a shape. Further, the gas chamber 15 is filled with nitrogen gas at a predetermined pressure. Note that a small gap S remains between the joining end surfaces of the flanges 3 and 3 'even when tightened by the tightening bolts 6, 6,.

When the heaters 2, 2,... At the outer peripheral portions of the cylinder units 1a, 1b,... Are heated to a predetermined temperature, and the screws 20 (20) are driven to rotate and the resin material is supplied, the resin material becomes well known. Is melted and kneaded, and is sent forward and extruded from a die. As a result, extruded products such as rods, pipes, sheets, and films can be obtained.

Gas generated when the resin material is melted and kneaded is extracted from the vent pipes 4 and 4 to the outside of the cylinder 1, and a part of the gas is separated by a gap S between the joint end faces of the flanges 3 and 3 ′.
Through the first groove 13. And the first
The gas pressure of the hollow metal ring body 10 enters the inside through the gas hole 11 and the gas pressure acts to expand the first hollow metal ring body 10, that is, as shown in FIG. A force that corrects any deformation is applied, and sealing is performed. At this time, the pressure of the nitrogen gas applied from the gas chamber 15 and the gas pressure in the cylinder 1 are balanced, and the seal is further secured. Since the second hollow metal ring body 12 is provided on the joint end face of the flanges 3 and 3 ′, the nitrogen gas in the gas chamber 15 does not leak out of the cylinder 1.

The present invention can be implemented in various forms without being limited to the above embodiment. For example, the present invention can be implemented only with the first hollow metal ring body 10. Even if only the first hollow metal ring body 10 is used, gas holes 11 are formed in the first hollow metal ring body 10 and gas pressure acts on the inside thereof, so that the sealing effect as described above is obtained. Is expensive. In addition, the first and second hollow metal ring bodies 10,
It is also possible to provide two seals to provide a double structure. At this time, the second hollow metal ring body 12 may also be provided with a plurality of gas holes in a portion facing the gas chamber 15 to enhance the sealing effect.

[0014]

As described above, according to the present invention, the seal device in the twin-screw extruder in which the axial end surfaces of the cylinder unit are joined via the seal device is provided in the radial direction at the end surface of the cylinder unit. A first hollow metal ring body disposed inside and a second hollow metal ring body disposed outside the first hollow metal ring body at a predetermined distance from the first hollow metal ring body.
A hollow metal ring body, and at least a position of the first hollow metal ring body facing the inner hole of the cylinder is provided with a through-hole communicating therewith. The chambers in which the two hollow metal ring bodies are respectively provided are connected by a gas chamber, and the gas chamber is filled with an inert gas, that is, the hollow metal ring body faces the inner hole of the cylinder. Since the through hole is opened at the position, the gas in the inner hole of the cylinder enters the inside of the hollow metal ring through the through hole and acts to expand it. Therefore, an effect peculiar to the present invention that a high sealing effect is maintained even if the tightening bolts of the cylinder unit are strong or weak is obtained. Thereby, the degassing effect is also enhanced, and the effect of obtaining a high-quality molded product is also obtained. Further, the chambers in which the first and second hollow metal ring bodies are provided are connected by a gas chamber, and the gas chamber is filled with an inert gas and the pressure is balanced, so that the pressure is further increased. A sealing effect is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.
Is a schematic cross-sectional view showing a partial cross section, (b) is an enlarged view of a main part, (c) is a cross-sectional view showing a further enlarged part of (b), and (d) is an operation. It is an expanded sectional view for explaining.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder 1a, 1b, ... Cylinder unit 3, 3 Flange 10, 12 First and second hollow metal ring body 11 Through hole 13, 14 First and second concave groove 15 Gas chamber 20 Screw

Claims (1)

(57) [Claims] 1. A cylinder (1) having a predetermined length and a screw (20) rotatably driven by an inner hole of the cylinder, wherein the cylinder (1) includes a plurality of cylinder units (1). 1a, 1b, ...), a twin-screw extruder in which end faces (3, 3 ') in the axial direction are joined to each other via a sealing device to have a predetermined length. Cylinder units (1a, 1b,
..), And a first hollow metal ring body (10) arranged radially inward at an end face thereof, and a predetermined distance from the first hollow metal ring body (10) outside thereof. At least the first hollow metal ring body (10).
At the position facing the inner hole of the cylinder (1), a through-hole (11) communicating therewith is opened, and the first and second hollow metal ring bodies (10, 12) are provided respectively. The two chambers (13, 14) are connected by a gas chamber (15), the gas chamber (15) being filled with an inert gas.