Extruder seal structure

Abstract

To provide an extruder seal structure that prevents air from entering the vacuum chamber without the seal partially tearing and mixing with the raw material, and that allows for efficient degassing of the raw material in the vacuum chamber. [Solution] A seal structure for an extruder 14 in which an extruder cylinder 13 having a vacuum chamber 17 following an upstream kneading chamber 16 is provided that can be divided in the left-right direction with respect to the longitudinal direction, wherein the upper and lower joining surfaces 19 of the extruder cylinder 13 when the divided extruder cylinder 13 are joined together have a seal 20 provided along the longitudinal direction, a seal portion 21 extending from the middle of the seal 20 toward the inner circumferential surface 22 of the extruder cylinder 13 on the upstream J side in front of the vacuum chamber 17, and a recess 23 provided between the seal portion 21 and the inner circumferential surface 22 of the extruder cylinder 13.

Description

Technical Field

[0001] The present invention relates to a seal structure of an extruder provided with a split extrusion cylinder and an air cutoff chamber such as a vacuum chamber.

Background Art

[0002] The applicant was unable to discover prior art document information to be described.

[0003] As a conventional technique, there is a seal structure of the following extruder 3 in which an extrusion cylinder 2 for housing an extrusion screw 1 rotatably provided inside is provided so as to be freely bisected in the left - right direction with respect to the longitudinal direction (see FIG. 1). Wheels (not shown) are provided at the lower parts of the respective extrusion cylinders 2 that are split on the left and right of the extruder 3. Below each extrusion cylinder 2, rails (not shown) are provided so that the wheels can move freely in the left - right direction.

[0004] Therefore, each extrusion cylinder 2 can be freely joined or separated in the left - right direction while leaving the extrusion screw 1 at the center. The split extrusion cylinder 2 is joined by tightening with bolts and nuts.

[0005] The extrusion cylinder 2 is mainly provided with a raw material inlet 4, a kneading chamber 5, a vacuum chamber 6 which is an air cutoff chamber, and a die (not shown) for extruding the kneaded raw material from the upstream J to the downstream K. The vacuum chamber 6 is evacuated by a vacuum pump (not shown).

[0006] At the boundary between the kneading chamber 5 and the vacuum chamber 6, a throttle member 7 (similar to an orifice) made of an annular plate material is attached in a state where the extrusion screw 1 penetrates through a central hole with a gap. The throttle member 7 also serves to apply resistance to the raw material extruded by the rotation of the extrusion screw 1. In this context, the vacuum chamber 6 refers to the space from the aperture material 7 to the nozzle downstream K.

[0007] The drawing material 7 blocks a portion of the raw material extruded by the rotation of the extrusion screw 1 towards the upstream J side, thereby creating a wall of densely compressed raw material. Therefore, a large portion of the air A flowing in with the raw materials from the raw material inlet 4 was prevented from entering the vacuum chamber 6, allowing for efficient degassing of the raw materials in the vacuum chamber 6.

[0008] Furthermore, seals 9 (rubber cord-shaped packings) are provided along the longitudinal direction on the upper and lower joining surfaces 8 of the extrusion cylinder 2 when they are joined. The seal 9 is designed to prevent air B and foreign matter that enter through the extremely small gap between the joint surfaces 8 when the divided extrusion cylinders 2 are joined from entering the vacuum chamber 6. Furthermore, seal 9 is also provided to prevent the raw material from leaking out of the extrusion cylinder 2.

[0009] Furthermore, a portion 10 of the seal 9 is provided to protrude extra from the inner circumferential surface 11 of the extrusion cylinder 2 on the upstream J side of the drawing material 7. Part 10 is designed to prevent air C and foreign matter that enter through the extremely small gap between the joint surfaces 8 near the raw material inlet 4 when the divided extrusion cylinders 2 are joined, from entering the vacuum chamber 6.

[0010] In addition, part 10 is intended to prevent air D, which flows in with the raw materials from the raw material inlet 4, flows into the extremely small gap between the lower joint surfaces 8, and then is blocked by the seal 9 before flowing back into the vacuum chamber 6.

[0011] Furthermore, the air C and D that flow into the mixing chamber 5 are prevented from flowing into the vacuum chamber 6 by the wall of raw materials blocked by the condensing material 7. Furthermore, the seal 9 and part 10 are fitted into grooves (not shown) provided on the upper and lower joining surfaces 8 of the extrusion cylinder 2 when they are joined. Therefore, the seal 9 and part 10 do not get in the way, and the upper and lower joining surfaces 8 of the extrusion cylinder 2 are joined together tightly.

[0012] Therefore, it was possible to prevent air and foreign matter from entering the vacuum chamber 6 with high precision, and to efficiently degas the raw materials in the vacuum chamber 6. However, the conventional seal structure of the extruder 3 had a problem in that a part 10 of the seal 9 that protruded excessively from the inner circumferential surface 11 of the extrusion cylinder 2 would partially tear off due to friction with the raw material extruded by the rotation of the extrusion screw 1, and this part would end up mixed into the raw material. [Overview of the Initiative] [Problems that the invention aims to solve]

[0013] The present invention aims to solve the above problems by providing an extruder seal structure that prevents air from entering the vacuum chamber without the seal partially tearing and mixing with the raw material, and that allows for efficient degassing of the raw material in the vacuum chamber. [Means for solving the problem]

[0014] The first means for solving the problem of the present invention is a seal structure for an extruder in which an extruder cylinder equipped with an air-blocking chamber following an upstream kneading chamber is provided to be divisible in the left-right direction with respect to the longitudinal direction, wherein the upper and lower joining surfaces of the extruder cylinder when the divided extruder cylinders are joined together have a seal provided along the longitudinal direction, a seal portion extending from the middle of the seal toward the inner circumferential surface of the extruder cylinder upstream of the air-blocking chamber, and a recess provided between the seal portion and the inner circumferential surface of the extruder cylinder.

[0015] A second means for solving the problem of the present invention is a means for solving the first problem, wherein a drawing material is provided at the boundary between the kneading chamber and the air-blocking chamber.

[0016] The third problem-solving means of the present invention is a seal structure of an extruder in which an extrusion cylinder having an air cutoff chamber following an upstream kneading chamber is provided so as to be vertically divisible with respect to the longitudinal direction, and when the divided extrusion cylinders are joined, on the joint surfaces on the left and right sides of the extrusion cylinder, seals provided along the longitudinal direction, a seal portion extending from the middle of the seal toward the inner peripheral surface of the extrusion cylinder on the upstream side in front of the air cutoff chamber, and a recess provided between the seal portion and the inner peripheral surface of the extrusion cylinder.

[0017] The fourth problem-solving means of the present invention is the third problem-solving means, in which a throttling material is provided at the boundary between the kneading chamber and the air cutoff chamber.

[0018] The fifth problem-solving means of the present invention is the first, second, third, or fourth problem-solving means, in which the air cutoff chamber is a vacuum chamber.

[0019] Note that the extruder of the present invention includes not only an extrusion molding machine and a clay kneader, but also a kneader, a mixer, etc. that knead and extrude raw materials. Further, the air cutoff chamber of the present invention includes not only a vacuum chamber, but also, for example, a chamber that needs to maintain an atmosphere of a certain concentration such as carbon dioxide gas or nitrogen.

Effects of the Invention

[0020] Since there is no seal that protrudes partially from the inner peripheral surface of the extrusion cylinder in the problem-solving means of the present invention, the seal is not partially torn and does not mix into the raw material. Furthermore, raw materials extruded by the rotation of the extrusion screw accumulate in the recess provided between the seal portion and the inner peripheral surface of the extrusion cylinder. The raw materials accumulated in the recess flow slowly downstream little by little, but raw materials always accumulate in the recess.

[0021] [[ID=三十一]] Therefore, by forming a block that includes a seal provided along the joint surface of the extrusion cylinder, a seal portion provided in the middle, and the raw material accumulated in the recess, air and foreign matter flowing through an extremely small gap between the joint surfaces near the raw material inlet when the divided extrusion cylinders are joined, and air that flows in together with the raw material from the raw material inlet, once flows into an extremely small gap between the lower joint surfaces, and then is blocked by the seal and flows in again can be prevented from flowing into the air cutoff chamber (vacuum chamber). Therefore, it is possible to prevent the inflow of air into the air cutoff chamber (vacuum chamber) with high precision, and it is possible to efficiently degas the raw material in the air cutoff chamber (vacuum chamber).

[0022] Note that the raw material accumulated in the recess slowly flows downstream little by little from the recess, but the frictional resistance between the seal portion and the raw material extruded by the rotation of the extrusion screw is extremely low. Therefore, it is impossible for a part of the seal portion to be torn by friction with the raw material extruded by the rotation of the extrusion screw and mixed into the raw material.

[0023] Furthermore, when a throttling material is provided at the boundary between the kneading chamber and the air cutoff chamber (vacuum chamber), a wall of the raw material compressed to a high density is created by blocking a part of the raw material extruded by the rotation of the extrusion screw toward the upstream side. Therefore, most of the air flowing in together with the raw material from the raw material inlet is prevented from flowing into the air cutoff chamber (vacuum chamber), and the raw material in the air cutoff chamber (vacuum chamber) can be degassed more efficiently.

Brief Description of the Drawings

[0024] [Figure 1] Partial side view of one part of the extruder split in the left - right direction in the background art [Figure 2] Partial side view of one part of the extruder of the present invention split in the left - right direction [Figure 3] Partial enlarged side view of one part of the extruder of the present invention split in the left - right direction [Modes for carrying out the invention]

[0025] The seal structure of the extruder of the present invention will be described (see Figure 2). Explanations of related technical aspects such as air piping and electrical wiring will be omitted.

[0026] The seal structure for the extruder of the present invention relates to an extruder 14 in which an extrusion cylinder 13, which houses an extrusion screw 12 that is rotatably mounted inside, is provided to be divisible into two parts in the left-right direction with respect to the longitudinal direction. Wheels (not shown) are provided at the bottom of each of the extrusion cylinders 13, which are divided into left and right sections of the extruder 14. Below each extrusion cylinder 13, rails (not shown) are provided so that the wheels can move freely in the left-right direction.

[0027] Therefore, each extrusion cylinder 13 can be freely joined or separated in the left-right direction while leaving the extrusion screw 12 in the center. The divided extrusion cylinder 13 is joined together by fastening with bolts and nuts.

[0028] The extrusion cylinder 13 is equipped with, from upstream J to downstream K, mainly a raw material inlet 15, a kneading chamber 16, a vacuum chamber 17 which is an air-blocking chamber, and a nozzle (not shown) for extruding the kneaded raw material. The vacuum chamber 17 is evacuated by a vacuum pump (not shown).

[0029] At the boundary between the mixing chamber 16 and the vacuum chamber 17, a ring-shaped plate material forming a drawing member 18 (a type of orifice) is attached, with the extrusion screw 12 passing through the central hole with a gap between them. The drawing material 18 also serves to add resistance to the raw material that is extruded by the rotation of the extrusion screw 12. In this context, the vacuum chamber 17 refers to the space from the aperture material 18 to the nozzle downstream K.

[0030] The drawing material 18 blocks a portion of the raw material extruded by the rotation of the extrusion screw 12 towards the upstream J side, thereby creating a wall of densely compressed raw material. Furthermore, the restricting element 18 only needs to have the function of restricting the flow path of the raw material to keep the flow rate constant, and its shape is not limited.

[0031] Furthermore, the drawing material 18 may have numerous through holes in addition to the hole through which the extrusion screw 12 passes. The drawing material 18 may also be a resistance plate, breaker plate, screen, etc., which are commonly used in clay mixers and extrusion molding machines.

[0032] Therefore, much of the air A that flows in with the raw materials from the raw material inlet 15 is prevented from flowing into the vacuum chamber 17, and the raw materials in the vacuum chamber 17 can be efficiently degassed. Furthermore, at the boundary between the kneading chamber 16 and the vacuum chamber 17, if the structure can prevent air A flowing in with the raw materials from the raw material inlet 15 from flowing into the vacuum chamber 17, then the pressing material 18 is not necessarily required. For example, any structure that can be created using partitions or similar materials to function as a vacuum chamber would suffice.

[0033] Furthermore, a seal 20 (a rubber cord-shaped packing) is provided along the longitudinal direction on the upper and lower joining surfaces 19 of the extrusion cylinder 13 when they are joined. The seal 20 is designed to prevent air B and foreign matter that enter through the extremely small gap between the joint surfaces 19 when the divided extrusion cylinders 13 are joined from entering the vacuum chamber 17. Furthermore, the seal 20 is also provided to prevent the raw material from leaking out of the extrusion cylinder 13.

[0034] Furthermore, grooves (not shown) for fitting and securing the seal 20 are provided in the longitudinal direction of the upper and lower joining surfaces 19 of the one and the other extrusion cylinder 13 that are joined. Therefore, the seal 20 does not get in the way, and the upper and lower joining surfaces 19 of the extrusion cylinder 13 are joined together tightly.

[0035] Furthermore, on the upstream J side in front of the vacuum chamber 17, a sealing portion 21 is provided in the middle of the seal 20 of the upper and lower joint surfaces 19 of the extrusion cylinder 13, extending toward the inner circumferential surface 22 of the extrusion cylinder 13. Furthermore, a recess 23 is provided between each seal portion 21 and the inner circumferential surface 22 of the extrusion cylinder 13.

[0036] The sealing portion 21 and the recess 23 are designed to prevent air C and foreign matter that enter through the extremely small gap between the joint surfaces 19 near the raw material inlet 15 when the divided extrusion cylinder 13 is joined, from entering the vacuum chamber 17.

[0037] In addition, the sealing portion 21 and the recess 23 are designed to prevent air D, which flows in with the raw material from the raw material inlet 15, flows into the extremely small gap between the lower joint surfaces 19, and then flows back into the vacuum chamber 17.

[0038] The sealing portion 21 consists of a cylindrical rubber packing. Furthermore, the sealing portion 21 is not limited to a cylindrical shape, but can be of any shape. Furthermore, grooves (not shown) for fitting and securing the seal portion 21 are provided in the longitudinal direction of the upper and lower joining surfaces 19 of the one and the other extrusion cylinder 13 that are joined. Therefore, the upper and lower joining surfaces 19 of the extrusion cylinder 13 are joined together tightly without the seal portion 21 getting in the way.

[0039] The recess 23 is a hole that extends from the inner circumferential surface 22 of the extrusion cylinder 13 to contact the seal portion 21. The side of the recess 23 facing the sealing portion 21 is completely sealed by the sealing portion 21. The area of ​​the recess 23 that contacts the sealing portion 21 is always smaller than the area of ​​the sealing portion 21 that contacts the recess 23.

[0040] In the portion of the recess 23 that connects to the inner circumferential surface 22 of the other extrusion cylinder 13, the upstream J-side wall surface 24 is provided at an inclination toward the upstream J side with respect to the inner circumferential surface 22, while the downstream K-side wall surface 25 is provided perpendicular to the inner circumferential surface 22 (see Figure 3).

[0041] The wall surface 24 on the upstream J side is designed to reduce resistance to the raw material extruded from the upstream J by the extrusion screw 12, making it easier for it to flow into the recess 23. The wall surface 25 on the downstream K side is intended to increase the density of the raw material that flows into the recess 23.

[0042] Therefore, raw materials extruded from the upstream J by the extrusion screw 12 tend to accumulate in the recess 23. The raw material accumulated in the recess 23 flows slowly from the recess 23 to the downstream K, but the recess 23 is always filled with raw material.

[0043] The shapes of the upstream J-side wall 24 and the downstream K-side wall 25 are not limited to those described above. The desired shape is one in which the raw material flows easily into the recess 23, but does not flow easily out of the recess 23, so that the raw material is always accumulated in the recess 23.

[0044] Therefore, by forming a block in which the seal 20 provided along the joint surface 19 of the extrusion cylinder 13, the seal portion 21 provided in the middle, and the raw material accumulated in the recess 23 are connected, it is possible to prevent air C and foreign matter that flows in through the extremely small gap between the joint surfaces 19 near the raw material inlet 15 when the divided extrusion cylinder 13 is joined, and air D that flows in with the raw material from the raw material inlet 15, flows into the extremely small gap between the lower joint surfaces 19, and then flows in again, from flowing into the vacuum chamber 17.

[0045] Therefore, the inflow of air into the vacuum chamber 17 can be prevented with high precision, and the raw materials in the vacuum chamber can be efficiently degassed. In this case, most of the air C and D that have flowed into the mixing chamber 16, along with most of the air A that flows in with the raw materials from the raw material inlet 15, are blocked by the raw material wall dammed by the condensing material 18 and do not flow into the vacuum chamber 17.

[0046] Furthermore, the raw material accumulated in the recess 23 flows slowly downstream to K little by little, but the frictional resistance between the seal portion 21 and the raw material extruded by the rotation of the extrusion screw 12 is extremely low. Therefore, a portion of the seal portion 21 does not tear off due to friction with the raw material extruded by the rotation of the extrusion screw 12 and become mixed into the raw material.

[0047] Another aspect of the present invention is the seal structure of an extruder in which an extrusion cylinder housing an extrusion screw rotatably mounted inside is provided to be divisible into two parts vertically with respect to the longitudinal direction. In this structure, a seal (rubber cord-like packing) is provided along the longitudinal direction on the left and right joint surfaces of the extrusion cylinder when joined, and a seal portion is provided on the upstream side in front of the vacuum chamber, extending from the middle of the seal toward the inner circumferential surface of the extrusion cylinder. Furthermore, recesses are provided between each seal portion and the inner circumferential surface of the extrusion cylinder. The other structural features are the same as the seal structure of the extruder 14 of the present invention described above, and their operation is also the same. [Explanation of Symbols]

[0048] 1. Extrusion Screw (Background Technology) 2. Extrusion Cylinder (Background Technology) 3. Extruders (Background Technology) 4 Raw material input port (background technology) 5. Mixing Room (Background Technology) 6 Vacuum chamber (background technology) 7. Die-retaining material (background technology) 8 Joint surface (background technology) 9. Seals (background technology) 10. Part of a sticker (background technology) 11. Inner surface of extrusion cylinder (background technology) 12 Extrusion Screws 13 Extrusion Cylinder 14 Extruder 15 Raw material input port 16 Mixing Room 17 Vacuum chamber 18. Drawing material 19 Joint surface 20 stickers 21 Seal part 22 Inner surface of the extrusion cylinder 23 Recess 24 Upstream wall 25 Downstream wall A. Inflowing air B Inflowing air C Inflowing air D Inflowing air J upstream K downstream

Claims

1. An extruder seal structure in which an extrusion cylinder equipped with an air-blocking chamber following an upstream kneading chamber is provided that can be divided in the left-right direction with respect to the longitudinal direction, A seal is provided along the longitudinal direction on the upper and lower joining surfaces of the extrusion cylinder when the divided extrusion cylinders are joined together, Upstream of the air-blocking chamber, a seal portion extends from the middle of the seal toward the inner circumferential surface of the extrusion cylinder, A device having a recess provided between the seal portion and the inner circumferential surface of the extrusion cylinder.

2. The seal structure for an extruder according to claim 1, A restricting material is provided at the boundary between the mixing chamber and the air-blocking chamber.

3. An extruder seal structure in which an extrusion cylinder equipped with an air-blocking chamber following an upstream kneading chamber is provided that can be divided vertically with respect to the longitudinal direction, A seal is provided along the longitudinal direction on the left and right joint surfaces of the extrusion cylinder when the divided extrusion cylinders are joined together, Upstream of the air-blocking chamber, a seal portion extends from the middle of the seal toward the inner circumferential surface of the extrusion cylinder, A device having a recess provided between the seal portion and the inner circumferential surface of the extrusion cylinder.

4. The seal structure for an extruder according to claim 3, A restricting material is provided at the boundary between the mixing chamber and the air-blocking chamber.

5. An extruder seal structure according to claim 1, 2, 3, or 4, The aforementioned air-blocked chamber is a vacuum chamber.

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