Ventilation obturator for extruder and extrusion device

Abstract

A ventilation obturator (20) for an extruder according to one embodiment is provided with a cylinder body (21) having a cylinder hole (30a), and a screw (23a) disposed in the cylinder hole (30a). The inner wall (31) of the cylinder hole (30a) has an upper surface portion (31a) and a lower surface portion (31b), and the screw (23a) is located between the upper surface portion (31a) and the lower surface portion (31b). The distance (C1) between the screw (23a) and the upper surface portion (31a) is larger than the distance (C2) between the screw (23a) and the lower surface portion (31b).

Description

Technical Field

[0001] The present invention relates to a vent plug for an extruder and an extrusion device. Background Art

[0002] It is known that an extruder melts, mixes or thermally decomposes raw materials and extrude them from a cylinder. Patent document 1 describes an extruder equipped with a vent stuffer. The vent stuffer is a degassing device that discharges gas from the cylinder of the extruder. The vent stuffer includes a cylinder connected to the cylinder of the extruder and a screw disposed in the cylinder.

[0003] The gas generated in the cylinder of the extruder flows into the cylinder of the vent plug and is recovered or released into the atmosphere through the cylinder of the vent plug. In addition, part of the raw materials and materials that flow out of the cylinder of the extruder together with the gas and flow into the cylinder of the vent plug remain in the cylinder of the vent plug or return to the cylinder of the extruder due to the screw of the vent plug.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2022-71945 Summary of the invention

[0007] Problems to be solved by the invention

[0008] Vent plugs for extruders and extruders are required to prevent raw materials and materials from being ejected from each cylinder.

[0009] Other issues and new features can be learned from the description and drawings of this specification.

[0010] Means for solving problems

[0011] According to one embodiment, a vent plug for an extruder includes a cylinder having a cylinder hole and a screw disposed in the cylinder hole. The inner wall of the cylinder hole has an upper surface portion and a lower surface portion, and the screw is located between the upper surface portion and the lower surface portion. Furthermore, the interval between the screw and the upper surface portion is greater than the interval between the screw and the lower surface portion.

[0012] Effects of the Invention

[0013] According to one embodiment, it is possible to prevent raw materials and materials from being ejected from the vent plug for an extruder or the cylinder of the extruder. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram which shows the structure of the extrusion apparatus which concerns on one Embodiment.

[0015] Figure 2It is along Figure 1 Cross-sectional view of the extrusion device along line AA.

[0016] Figure 3 It is along Figure 2 An enlarged cross-sectional view of line XX in FIG.

[0017] Figure 4 It is along Figure 2 An enlarged cross-sectional view of line YY in FIG.

[0018] Figure 5 It is along Figure 2 An enlarged cross-sectional view of line ZZ in FIG.

[0019] Figure 6 It is a cross-sectional view showing the height of the internal space of the cylinder according to one embodiment.

[0020] Figure 7 This is a cross-sectional view showing the relationship between the maximum diameter of the main screw and the maximum diameter of the screw in one embodiment.

[0021] Figure 8 This is a cross-sectional view showing a chamber and its vicinity according to one embodiment.

[0022] Fig. 9 It is another cross-sectional view showing the chamber and its vicinity according to one embodiment. DETAILED DESCRIPTION

[0023] Hereinafter, an embodiment is described in detail based on the accompanying drawings. It should be noted that in all the drawings used to illustrate the embodiments, the same reference numerals are used for devices and components having the same or substantially the same functions. In addition, devices and components that have been described once are not described repeatedly in principle.

[0024] <Extrusion device configuration>

[0025] Figure 1 Schematic diagram showing the configuration of the extrusion device 1 of the present embodiment. The extrusion device 1 includes an extruder body 10 and an extruder vent plug 20. In the following description, the extruder vent plug 20 may be simply referred to as a "vent plug 20".

[0026] The extrusion device 1 of the present embodiment can process waste plastics through the following process. More specifically, the extrusion device 1 of the present embodiment can recycle waste plastics through the following process.

[0027] First, the crushed waste plastic is supplied to the extruder body 10. More specifically, the waste plastic is supplied into the cylinder 11 through the raw material supply port 12 provided at or near the rear end of the cylinder 11. It should be noted that, although not shown in the figure, the raw material supply port 12 is connected to a hopper into which the waste plastic is put.

[0028] The waste plastic supplied to the extruder body 10 is, for example, plastic flakes discarded as household garbage or industrial waste and crushed by a crusher. In the following description, the waste plastic supplied to the extruder body 10 may be referred to as "raw material".

[0029] The raw material supplied to the extruder body 10 is conveyed toward the front end of the cylinder 11 while being kneaded. More specifically, the raw material supplied to the cylinder 11 is melt-kneaded while being conveyed forward by the rotation of a screw provided in the cylinder 11.

[0030] The raw materials (kneaded material / molten resin) kneaded by the extruder body 10 are extruded to the outside through a die head attached to the front end of a cylinder 11. The kneaded material is formed into a strip (rope, cord) by passing through the nozzle of the die head.

[0031] The kneaded product in the form of strips extruded from the die is cut by a cutting device (granulator). From another perspective, the kneaded product in the form of strips extruded from the die is cut into pellets. As a result, resin pellets of the desired size (length and thickness) are obtained.

[0032] In the above process, gas may be generated in the cylinder 11 of the extruder body 10. For example, volatile gas may be generated in combination with the kneading and melting of raw materials. In particular, waste plastics often contain water, which may generate a large amount of gas.

[0033] The vent plug 20 includes a cylinder 21 connected to the cylinder 11 of the extruder body 10, and extracts gas from the cylinder 11 of the extruder body 10. In the following description, the cylinder 11 of the extruder body 10 is sometimes referred to as a "main cylinder 11" to distinguish it from the cylinder 21 of the vent plug 20.

[0034] The main cylinder 11 of the extruder body 10 is connected to the cylinder 21 of the vent plug 20. Therefore, the gas generated in the main cylinder 11 flows into the cylinder 21 of the vent plug 20, and a part of the kneaded material and particles (hereinafter sometimes collectively referred to as "ejecta") sometimes flow in together with the gas.

[0035] Therefore, a screw is provided in the cylinder 21 of the vent plug 20. The ejected material flowing into the cylinder 21 from the main cylinder 11 stays in the cylinder 21 or returns to the main cylinder 11 due to the rotation of the screw provided in the cylinder 21. In the following description, the screw provided in the extruder body 10 is sometimes referred to as a "main screw" to distinguish it from the screw provided in the vent plug 20.

[0036] It should be noted that, although not shown in the figure, the extruder body 10 is placed on the machine base. On the other hand, the vent plug 20 is placed on a support table 22 for making the height consistent with the extruder body 10. Of course, there is also an embodiment in which the vent plug 20 is equipped with a support portion, a support leg, etc. instead of the support table 22.

[0037] <Extruder body>

[0038] Next, the extruder main body 10 will be described in more detail. Figure 2 It is along Figure 1 A cross-sectional view of the extrusion device 1 along the AA line in FIG. Figure 2 in, omit Figure 1 The support platform 22 is shown.

[0039] like Figure 1 , Figure 2 As shown, the extruder body 10 includes a main cylinder 11, a raw material supply port 12, main screws 13a and 13b, and a drive unit 14. From another perspective, the extruder body 10 is a twin-screw extruder having two screws arranged in parallel.

[0040] The master cylinder 11 is formed of a plurality of blocks arranged in a row. More specifically, the master cylinder 11 is formed of seven blocks 15a, 15b, 15c, 15d, 15e, 15f, and 15g arranged in a row.

[0041] Each block 15a, 15b, 15c, 15d, 15e, 15f, and 15g has a through hole. The through holes provided in each block 15a to 15g communicate with each other, thereby forming a cylinder hole 16 inside the master cylinder 11.

[0042] The cylinder hole 16 includes a cylinder hole 16a where the main screw 13a is arranged and a cylinder hole 16b where the main screw 13b is arranged. The cylinder hole 16a and the cylinder hole 16b are arranged in parallel and communicate with each other.

[0043] Two opposing protrusions 17 are provided between the cylinder hole 16a and the cylinder hole 16b. One protrusion 17 protrudes downward, and the other protrusion 17 protrudes upward. That is, the master cylinder 11 is a glasses shape. From another perspective, the top and bottom surfaces of the cylinder hole 16 are not flat.

[0044] The driving unit 14 includes a motor and a speed reducer. The main screws 13a and 13b are rotationally driven by a driving force output from the motor and input via the speed reducer.

[0045] The raw material put into the hopper falls into the cylinder hole 16 through the raw material supply port 12. The raw material falling into the cylinder hole 16 is kneaded and conveyed forward by the main screws 13a and 13b rotating in the cylinder hole 16. At the same time, the raw material is melted by the heat generated by the heat from the heater provided in the main cylinder 11 and the heat generated by shearing heat.

[0046] It should be noted that the raw material supply port 12 is provided on the upper surface of the last block 15g, and the driving unit 14 is arranged further behind the block 15g.

[0047] <Overview of Ventilation Tamper>

[0048] Figure 3 It is along Figure 2 An enlarged cross-sectional view of line XX in FIG. Figure 4 It is along Figure 2 An enlarged cross-sectional view of line YY in FIG. Figure 5 It is along Figure 2 An enlarged cross-sectional view of line ZZ in FIG.

[0049] The vent plug 20 includes a cylinder 21, screws 23a and 23b, a drive unit 24, and a chamber 25. From another perspective, the vent plug 20 is a double-shaft degassing device having two screws arranged in parallel.

[0050] <Cylinder>

[0051] The cylinder 21 of the vent plug 20 is connected to one of the blocks forming the main cylinder 11 of the extruder body 10. More specifically, the cylinder 21 is connected to the side of the block 15c. From another perspective, the cylinder 21 of the vent plug 20 is orthogonal to the main cylinder 11 of the extruder body 10.

[0052] It should be noted that, in other embodiments, the cylinder 21 of the ventilation plug 20 may also be connected to the upper surface of the block 15c or other blocks.

[0053] <Cylinder bore>

[0054] The cylinder body 21 of the breather plug 20 has a cylinder hole 30 that communicates with the cylinder hole 16 of the master cylinder 11. Figure 4 As shown, the cylinder hole 30 includes a cylinder hole 30a for the screw rod 23a and a cylinder hole 30b for the screw rod 23b.

[0055] The cylinder bore 30a and the cylinder bore 30b are arranged in parallel and communicate with each other. In addition, the cylinder bore 30a and the cylinder bore 30b have the same cross-sectional shape and cross-sectional area. More specifically, the cylinder bore 30a and the cylinder bore 30b have the following cross-sectional shape: Figure 4 The imaginary straight line VL shown is a cross-sectional shape symmetrical about the axis of symmetry.

[0056] Each cylinder hole 30a, 30b has an inner wall 31 including an upper surface portion 31a, a lower surface portion 31b, and a side surface portion 31c. The screw 23a is located between the upper surface portion 31a and the lower surface portion 31b of the inner wall 31 of the cylinder hole 30a. The screw 23b is located between the upper surface portion 31a and the lower surface portion 31b of the inner wall 31 of the cylinder hole 30b.

[0057] From another perspective, the upper surface 31a and lower surface 31b of the inner wall 31 of the cylinder hole 30a face each other via the screw 23a. Similarly, the upper surface 31a and lower surface 31b of the inner wall 31 of the cylinder hole 30b face each other via the screw 23b.

[0058] The side surface portion 31c of the cylinder hole 30a connects one side of the upper surface portion 31a of the cylinder hole 30a with one side of the lower surface portion 31b. Similarly, the side surface portion 31c of the cylinder hole 30b connects one side of the upper surface portion 31a of the cylinder hole 30b with one side of the lower surface portion 31b. As a result, the side surface portion 31c of the cylinder hole 30a and the side surface portion 31c of the cylinder hole 30b face each other with the screw rod 23a and the screw rod 23b interposed therebetween.

[0059] From another perspective, the upper surface portion 31a of the cylinder hole 30a forms the top surface of the cylinder hole 30a, the lower surface portion 31b forms the bottom surface of the cylinder hole 30a, and the side surface portion 31c forms the inner side surface of the cylinder hole 30a. Similarly, the upper surface portion 31a of the cylinder hole 30b forms the top surface of the cylinder hole 30b, the lower surface portion 31b forms the bottom surface of the cylinder hole 30b, and the side surface portion 31c forms the inner side surface of the cylinder hole 30b.

[0060] The upper surface 31a of each cylinder bore 30a, 30b is flat. In addition, the upper surface 31a of the cylinder bore 30a and the upper surface 31a of the cylinder bore 30b form a plane that is continuous without a boundary. From another perspective, the upper surface 31a of the cylinder bore 30a and the upper surface 31a of the cylinder bore 30b are continuous, forming a flat top surface of the cylinder bore 30.

[0061] The lower surface portion 31b of each cylinder hole 30a, 30b is a curved surface. More specifically, the lower surface portion 31b of the cylinder hole 30a is a curved surface along the screw rod 23a, and the lower surface portion 31b of the cylinder hole 30b is a curved surface along the screw rod 23b.

[0062] A mountain-shaped protrusion 32 protruding upward is provided between the lower surface portion 31b of the cylinder bore 30a and the lower surface portion 31b of the cylinder bore 30b. From another perspective, a sharp protrusion 32 protruding toward the top surface is provided on the bottom surface of the cylinder bore 30. In other words, the top surface of the cylinder bore 30 is flat, while the bottom surface of the cylinder bore 30 is not flat. It should be noted that Figure 4 The virtual straight line VL shown is also a vertical line passing through the apex of the protrusion 32 .

[0063] <Connection hole>

[0064] like Figure 2 As shown, the main cylinder 11 of the extruder body 10 is provided with a connecting hole 18 for connecting the main cylinder 11 with the cylinder body 21 of the vent plug 20. The connecting hole 18 is provided in the block 15c connected to the cylinder body 21. The connecting hole 18 penetrates the side wall of the block 15c to connect the cylinder hole 16 with the cylinder hole 30.

[0065] like Figure 3 , Figure 4 As shown, the connection hole 18 has the same cross-sectional shape and cross-sectional area as the cylinder hole 30. Furthermore, the front end portions of the screw rods 23a and 23b protruding from the cylinder body 21 of the ventilation plug 20 are inserted into the connection hole 18. More specifically, the front end portion of the screw rod 23a protruding from the cylinder hole 30a is inserted into one side of the connection hole 18 connected to the cylinder hole 30a, and the front end portion of the screw rod 23b protruding from the cylinder hole 30b is inserted into the other side of the connection hole 18 connected to the cylinder hole 30b.

[0066] From another perspective, the screws 23a, 23b of the ventilation plug 20 span the cylinder body 21 and the main cylinder 11 (see Figure 2 ).

[0067] <Interval>

[0068] like Figure 4 As shown, the interval C1 between the screw rod 23a and the upper surface portion 31a of the cylinder hole 30a is greater than the interval C2 between the screw rod 23a and the lower surface portion 31b of the cylinder hole 30a. Similarly, the interval C1 between the screw rod 23b and the upper surface portion 31a of the cylinder hole 30b is greater than the interval C2 between the screw rod 23b and the lower surface portion 31b of the cylinder hole 30b. From another perspective, the interval C1 between the screw rods 23a, 23b and the top surface of the cylinder hole 30 is greater than the interval C2 between the screw rods 23a, 23b and the bottom surface of the cylinder hole 30.

[0069] Regardless of the rotation angle of the screws 23a and 23b, the intervals C1 and C2 always maintain the above-mentioned size relationship (C1>C2). In addition, the above-mentioned size relationship (C1>C2) is maintained throughout the entire length of the cylinder body 21. Further, in the connecting holes 18 having the same cross-sectional shape and cross-sectional area as the cylinder bores 30, the same or substantially the same size relationship is established.

[0070] Figure 6 2 is a cross-sectional view showing the internal space height of the cylinder block 21. In the present embodiment, the above-mentioned size relationship between the interval C1 and the interval C2 (C1>C2) is achieved by flattening the top surface of the cylinder hole 30. From another perspective, by flattening the top surface of the cylinder hole 30, the internal space height of the cylinder block 21 is increased.

[0071] More specifically, Figure 6 The relative distance Fd between the upper surface portion 31a and the lower surface portion 31b of the cylinder hole 30a shown is set to be 1.1 times or more the maximum diameter (diameter / long diameter) d of the screw 23a. From another perspective, the ratio (Fd / d) of the relative distance Fd to the maximum diameter d is 1.1 or more.

[0072] in addition, Figure 6 The relative distance Fd between the upper surface portion 31a and the lower surface portion 31b of the cylinder hole 30b (not shown) is also 1.1 times or more the maximum diameter (diameter) d of the screw rod 23b.

[0073] It should be noted that, as described above, the top surface of the cylinder hole 30 is formed by the upper surface portion 31a of each cylinder hole 30a, 30b, and the bottom surface of the cylinder hole 30 is formed by the lower surface portion 31b of each cylinder hole 30a, 30b. Therefore, the relative distance Fd between the upper surface portion 31a and the lower surface portion 31b is equivalent to the internal space height of the cylinder body 21.

[0074] In the present embodiment, the internal space height of the cylinder 21 is set to a height satisfying the condition of (Fd / d≥1.1), and the centers of the screws 23 a and 23 b are eccentric downward with respect to the center of the cylinder hole 30 .

[0075] From another perspective, in the present embodiment, a wider space is secured above the screws 23a and 23b in the cylinder bore 30 than below the screws 23a and 23b. Therefore, the flow rate of the gas flowing from the cylinder bore 16 through the connecting hole 18 into the cylinder bore 30 is decelerated or at least the speed is suppressed. As a result, the ejection material flowing from the master cylinder 11 into the cylinder body 21 can be prevented or suppressed from being ejected from the cylinder body 21.

[0076] In addition, the ejected matter that flows into the cylinder 21 together with the air flow stays in the cylinder 21 or returns to the master cylinder 11 due to the rotating screws 23 a and 23 b.

[0077] Here, from the viewpoint of decelerating the airflow, it is preferred to make the space around the screws 23a, 23b (the gap between the cylinder hole 30 and the screws 23a, 23b) larger. Specifically, it is preferred to make the above-mentioned ratio (Fd / d) larger. However, according to the research of the inventors of the present application, if the above-mentioned ratio (Fd / d) exceeds 2.0, the flow rate of the airflow is approximately constant. In addition, if the relative interval Fd is increased in order to increase the above-mentioned ratio (Fd / d), the strength and durability of the cylinder body 21 may be reduced, and the cylinder body 21 may also be enlarged. From this viewpoint, the ratio (Fd / d) is preferably greater than 1.1 and less than 2.0, and more preferably greater than 1.5 and less than 2.0.

[0078] In addition, even if the interval C1 is the same as the interval C2, if the space around the screws 23a and 23b is increased, the airflow is decelerated. However, if the space around the screws 23a and 23b is too large, the conveying capacity of the screws 23a and 23b may be reduced. In other words, the ability to keep the ejected material in the cylinder body 21 or return it to the main cylinder 11 may be reduced.

[0079] From the viewpoint of maintaining / improving the conveying capacity of the screws 23a and 23b, the interval C2 is preferably as small (narrow) as possible. That is, it is preferable to achieve a desired ratio (Fd / d) by minimizing the interval C2 and maximizing the interval C1.

[0080] In the present embodiment, flattening the top surface of the cylinder bore 30 contributes to achieving the desired ratio (Fd / d) based on minimizing the interval C2 and maximizing the interval C1. However, flattening the bottom surface of the cylinder bore 30 is not excluded.

[0081] On the other hand, the gas flow, especially the volatile gas flow, flowing into the cylinder hole 30 passes through the upper part of the cylinder hole 30. In contrast, most of the ejected matter flowing into the cylinder hole 30 falls to the lower part of the cylinder hole 30 due to its own weight. Therefore, from the viewpoint of maintaining the conveying capacity of the screws 23a and 23b and decelerating the gas flow, it is preferable to achieve the desired ratio (Fd / d) by minimizing the interval C2 and maximizing the interval C1. For this purpose, it is effective to set the top surface of the cylinder hole 30 to a flat surface and the bottom surface to a curved surface.

[0082] <Securing the interval between screw diameters>

[0083] The above-mentioned magnitude relationship (C1>C2) between the interval C1 and the interval C2 can also be achieved by reducing the diameters of the screws 23a and 23b. Figure 7 It is a cross-sectional view showing the relationship between the maximum diameter D of the main screws 13a and 13b of the extruder body 10 and the maximum diameter d of the screws 23a and 23b of the vent plugger.

[0084] Obviously, Figure 7 The smaller the maximum diameter d of the screw 23a shown, the larger the interval C1 is. From another perspective, if the maximum diameter d of the screw 23a is reduced, a larger space is generated above the screw 23a in the cylinder hole 30.

[0085] However, if the maximum diameter d of the screw 23a is too small, the conveying capacity of the screw 23a will be insufficient. Therefore, when the above-mentioned size relationship (C1>C2) is achieved by reducing the diameter of the screw 23a, the maximum diameter d of the screws 23a and 23b is preferably not less than 0.2 times and not more than 0.8 times the maximum diameter D of the main screws 13a and 13b, and more preferably not less than 0.4 times and not more than 0.8 times.

[0086] <Chamber>

[0087] Figure 8 2 is a cross-sectional view showing the chamber 25 and its vicinity. The chamber 25 has a cylindrical buffer chamber 40 and an exhaust pipe 41 extending from the buffer chamber 40. An opening 43 communicating with the cylinder hole 30 is provided at the bottom of the buffer chamber 40, and the exhaust pipe 41 is connected to a vacuum pump P.

[0088] The gas generated in the master cylinder 11 passes through the cylinder block 21 (cylinder hole 30 ) to reach below the opening 43 , and flows into the damper chamber 40 from the opening 43 . Then, the gas is sucked out from the damper chamber 40 through the exhaust pipe 41 .

[0089] Here, increasing the area of ​​the opening 43 is effective to prevent the ejected matter that arrives below the opening 43 together with the gas from flowing out of the buffer chamber 40. From another perspective, increasing the area of ​​the opening 43 is effective to prevent the ejected matter from flowing into the exhaust pipe 41 via the buffer chamber 40.

[0090] The gas and the ejected material flow from the front end side to the rear end side in the cylinder hole 30 along the axial direction of the screws 23a and 23b and reach the opening 43. Therefore, in order to prevent the ejected material from flowing out, Figure 8 It is effective that the length L shown is increased to increase the area of ​​the opening portion 43 . Figure 8 The length L shown is the length from one side (front end side) to the other side (rear end side) of the opening 43 along the axial direction of the screws 23a and 23b.

[0091] Fig. 9 4 is a cross-sectional view showing the chamber 25 and its vicinity with the opening 43 having an increased area. Fig. 9 As shown in FIG. 1 , by increasing the length L of the opening 43, the ejected matter reaching the opening 43 does not flow into the buffer chamber 40, and the probability of falling into the cylinder hole 30 due to its own weight increases. In addition, the probability of the ejected matter once flowing into the buffer chamber 40 falling into the cylinder hole 30 due to its own weight also increases. In short, the probability of the ejected matter being sucked out of the buffer chamber 40 together with the gas is reduced.

[0092] From the viewpoint of improving the above-mentioned effect of collecting the ejected matter by free fall, the length L is preferably 2.0 times or more, and more preferably 3.0 times or more, the maximum diameter d of the screws 23a and 23b.

[0093] It should be noted that, when the ejection portion is small (light), it is preferred to increase the length L to increase the possibility of the ejection material falling freely. On the other hand, when the ejection portion is large (heavy), it is preferred to shorten the length L to increase the conveying capacity of the screws 23a and 23b.

[0094] As mentioned above, the invention proposed by the inventors of the present application has been specifically described based on the embodiments and examples. However, the present invention is not limited to the above-mentioned embodiments or examples, and various modifications can be made without departing from the scope of the invention.

[0095] For example, the use of the extruder is not limited to the treatment of waste plastics. The extruder can be used for melting, kneading, degassing, etc. of various raw materials and materials.

[0096] The form of the raw material or material to be processed by the extruder is not particularly limited. The extruder can process raw materials or materials in various forms such as granular, granular, and powdery forms.

[0097] The screws of the extruder main body and the vent plug for extruder may be of an intermeshing type or a non-intermeshing type. However, the extruder main body and the vent plug for extruder are not limited to a twin-screw type.

[0098] Description of Reference Numerals

[0099] 1...extrusion device, 10...extruder body, 11...cylinder (main cylinder), 12...raw material supply port, 13a, 13b...screw (main screw), 14...driving unit, 15a to 15g...block, 16, 16a, 16b...cylinder hole, 17...protrusion, 18...connecting hole, 20...vent plug for extruder (vent plug), 21...cylinder, 22...support table, 23a, 23b... Screw, 24... driving part, 25... chamber, 30, 30a, 30b... cylinder hole, 31... inner wall, 31a... upper surface part, 31b... lower surface part, 31c... side part, 32... protrusion part, 40... buffer chamber, 41... exhaust pipe, 43... opening part, C1, C2... interval, d... maximum diameter (mountain diameter), D... maximum diameter, Fd... relative interval, P... vacuum pump, VL... virtual straight line

Claims

1. A vent plug for an extruder, characterized in that: Include: A cylinder body having a cylinder hole connected to the extruder body; and A screw rod is disposed in the cylinder hole. The inner wall of the cylinder hole has an upper surface portion and a lower surface portion, The screw is located between the upper surface portion and the lower surface portion, A distance between the screw and the upper surface portion is greater than a distance between the screw and the lower surface portion.

2. The vent plug for an extruder according to claim 1, wherein The upper surface portion is a plane, The lower surface portion is a curved surface along the screw.

3. The vent plug for an extruder according to claim 1, wherein: The relative distance between the upper surface portion and the lower surface portion is 1.1 times or more of the maximum diameter of the screw.

4. The vent plug for an extruder according to claim 1, wherein The maximum diameter of the screw is 0.8 times or less of the maximum diameter of the screw included in the extruder body.

5. The vent plug for an extruder according to claim 1, wherein A chamber is provided, the chamber is arranged above the cylinder body and has an opening portion communicating with the cylinder hole, A length of the opening from one side to the other side along the axial direction of the screw is 2.0 times or more the maximum diameter of the screw.

6. The vent plug for an extruder according to claim 1, wherein The screw includes a first screw and a second screw, The cylinder hole includes a first cylinder hole for arranging the first screw rod and a second cylinder hole for arranging the second screw rod. The upper surface portion of the first cylinder hole and the upper surface portion of the second cylinder hole are continuous planes, The lower surface of the first cylinder hole is a curved surface along the first screw rod. The lower surface portion of the second cylinder hole is a curved surface along the second screw.

7. An extrusion device, characterized in that: Include: an extruder body; and an extruder vent plug connected to the extruder body, The extruder body has a main cylinder with a cylinder hole and a main screw arranged in the cylinder hole. The vent plug for the extruder comprises a cylinder body connected to the main cylinder and having a cylinder hole, and a screw arranged in the cylinder hole. The inner wall of the cylinder hole of the vent plug for the extruder has an upper surface portion and a lower surface portion. The screw of the vent plugger for an extruder is located between the upper surface portion and the lower surface portion, A distance between the screw and the upper surface portion is greater than a distance between the screw and the lower surface portion.

8. The extrusion device according to claim 7, wherein: The maximum diameter of the screw of the vent plugger for extruder is 0.8 times or less of the maximum diameter of the main screw of the extruder body.

9. The extrusion device according to claim 7, wherein: The main cylinder of the extruder body is provided with a connection hole for connecting the main cylinder with the cylinder body of the extruder ventilation plugger. The connecting hole has the same cross-sectional shape and cross-sectional area as the cylinder hole of the vent plug for the extruder, The front end portion of the screw of the vent plugger for extruder protruding from the cylinder of the vent plugger for extruder is inserted into the connecting hole.

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