A twin screw extruder

Abstract

The present invention discloses a twin-screw extruder, comprising a barrel, a first screw, a second screw and a driving mechanism; the barrel is provided with a containing cavity, and the side wall of the barrel is provided with a feed port connected to the containing cavity; the first screw and the second screw extend into the containing cavity, the first screw and the second screw are meshed with each other, and the driving mechanism is connected to the first screw and can drive the first screw to rotate; the first screw and the second screw are both provided with a working section, and the diameter of the working section of the second screw is different from the diameter of the working section corresponding to the first screw.

Description

Technical Field

[0001] The invention relates to the field of machinery, in particular to a twin-screw extruder. Background Art

[0002] The principle of the extruder is to use a screw of a specific shape to rotate in a heated barrel. The surface of the screw is provided with working sections with different texture shapes. Each working section has a different function. The plastic sent from the hopper is squeezed forward to melt the plastic evenly. The plastic is extruded into continuous plastic layers of various shapes required through the machine head and molds of different shapes.

[0003] Extruders are mainly divided into single-screw extruders and twin-screw extruders. The existing twin-screw extruders use a motor to drive two screws with the same radial size through a reduction gearbox. The gearbox transmission of this extruder produces greater vibration and noise, making the working environment worse. Summary of the invention

[0004] In order to overcome the shortcomings and deficiencies of the prior art, the present invention discloses a twin-screw extruder, comprising a barrel, a first screw, a second screw and a driving mechanism; the barrel is provided with a accommodating chamber, and the side wall of the barrel is provided with a feed port connected to the accommodating chamber; the first screw and the second screw extend into the accommodating chamber, the first screw and the second screw are meshed with each other, and the driving mechanism is connected to the first screw and can drive the first screw to rotate; the first screw and the second screw are both provided with a working section, and the diameter of the working section of the second screw is different from the diameter of the working section corresponding to the first screw.

[0005] As a further improvement of the present invention, the diameter of the working section of the second screw is smaller than the diameter of the corresponding working section of the first screw.

[0006] As a further improvement of the present invention, it further comprises a first meshing gear shaft and a second meshing gear shaft, wherein the first meshing gear shaft and the second meshing gear shaft mesh with each other; and the first meshing gear shaft is connected to the driving mechanism.

[0007] As a further improvement of the present invention, the first meshing gear shaft and the second meshing gear shaft are located outside the barrel.

[0008] As a further improvement of the present invention, it further includes a first coupling and a second coupling, wherein the first meshing gear shaft is connected to the first screw rod through the first coupling; and the second meshing gear shaft is connected to the second screw rod through the second coupling.

[0009] As a further improvement of the present invention, the working section of the first screw includes a feeding section, and the feeding section of the first screw has a feeding thread.

[0010] As a further improvement of the present invention, a second screw feeding section is arranged at a position corresponding to the feeding section of the first screw, and the second screw feeding section includes a smooth rod portion, a sealing thread and a feeding thread arranged in sequence from the connecting port to the discharge port.

[0011] As a further improvement of the present invention, the barrel is provided with an inwardly protruding barrier portion, and the barrier portion is located between the sealing threads and the polished rod portion of the first screw feeding section and the second screw feeding section.

[0012] As a further improvement of the present invention, a second screw feeding section is arranged at a position corresponding to the feeding section of the first screw, and the second screw feeding section includes a smooth rod portion, a sealing thread and a feeding thread arranged in sequence from the connecting port to the discharge port.

[0013] As a further improvement of the present invention, the barrel is provided with an inwardly protruding barrier portion, and the barrier portion is located between the sealing threads and the polished rod portion of the first screw feeding section and the second screw feeding section.

[0014] As a further improvement of the present invention, the feeding section of the first screw includes a plurality of thread sleeve blocks.

[0015] As a further improvement of the present invention, the working section of the first screw includes a compression section and a mixing and plasticizing section; the working section of the second screw includes a compression section and a mixing and plasticizing section which are arranged in sequence.

[0016] As a further improvement of the present invention, the compression section and the mixing and plasticizing section both include a plurality of working blocks.

[0017] As a further improvement of the present invention, adjacent working blocks in the compression section are staggered at a certain angle so that the multiple working blocks in the compression section are arranged in a spiral manner.

[0018] As a further improvement of the present invention, adjacent working blocks in the mixing and plasticizing section are staggered by 90°.

[0019] As a further improvement of the present invention, the working block is an elliptical flat block provided with a mounting hole.

[0020] As a further improvement of the present invention, the accommodating chamber includes a first accommodating chamber and a second accommodating chamber, both of which are cylindrical. The first accommodating chamber is used to accommodate the first screw rod, and the second accommodating chamber is used to accommodate the second screw rod. The diameter of the first accommodating chamber is larger than the diameter of the second accommodating chamber.

[0021] A twin-screw extruder of the present invention sets the diameter corresponding to the second screw to be smaller than the diameter corresponding to the first screw, so that the first screw can be driven by a driving mechanism to drive the second screw to rotate, avoiding the need for a reduction gearbox and reducing noise generated during operation.

[0022] For better understanding and implementation, the present invention is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the first embodiment of the present invention.

[0024] Figure 2 It is a front cross-sectional view of the first embodiment of the present invention.

[0025] Figure 3 It is a top cross-sectional view of the first embodiment of the present invention.

[0026] Figure 4 yes Figure 3 Sectional view along AA direction.

[0027] Figure 5 It is an exploded schematic diagram of the first screw rod in the first embodiment of the present invention.

[0028] Figure 6 It is a schematic diagram of the working blocks of the present invention.

[0029] Figure 7 It is a schematic diagram of the first screw compression section of the present invention.

[0030] Figure 8 It is a schematic diagram of the first screw mixing and plasticizing section of the present invention.

[0031] Fig. 9 It is a cross-sectional schematic diagram of the first screw mixing and plasticizing section of the present invention.

[0032] Fig.10 It is a schematic diagram of the second embodiment of the present invention. DETAILED DESCRIPTION

[0033] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0034] Embodiment 1

[0035] See also Figure 1-9The present invention discloses a twin-screw extruder, which includes a barrel 10, a first screw 20, a second screw 30 and a driving mechanism 40; the barrel 10 is provided with a receiving chamber, and the side wall of the barrel 10 is provided with a feed port 11 connected to the receiving chamber; the first screw 20 and the second screw 30 extend into the receiving chamber, the first screw 20 and the second screw 30 are meshed with each other, and the first screw 20 and the second screw 30 are both provided with a plurality of working sections, and the diameter of the working section of the second screw is different from the diameter of the working section corresponding to the first screw. In this embodiment, the diameter of the working section of the second screw 30 is smaller than the diameter of the working section corresponding to the first screw 20. The driving mechanism 40 is connected to the first screw 20 and can drive the first screw 20 to rotate. Through such an arrangement, the diameter of the working section corresponding to the second screw 30 is smaller than the diameter of the working section of the first screw 20, and the rotation torque required in the extruder is reduced, so the gear box can be omitted, avoiding the noise that may be generated by the gear box. The first screw 20 is directly driven to rotate by the driving mechanism 40, and the first screw 20 drives the second screw 30 to rotate, so that the extrusion process can be completed. The working section refers to a section of texture formed on the surface of the screw. A screw can be provided with multiple different working sections, and the texture set in each working section plays a specific role, for example, it can realize operations such as conveying, rolling, and melting plastic particles.

[0036] In this embodiment, the two ends of the barrel 10 are respectively provided with a discharge port 12 and a connection port 13 connected to the accommodating chamber, the first screw 20 and the second screw 30 are inserted from the connection port 13, and the first screw 20 is connected to the driving mechanism 40 through one end close to the connection port 13. After the plastic material is processed, it is extruded from the discharge port 12 of the barrel 10. The length direction of the accommodating chamber extends from the connection port 13 to the discharge port 12. An upper hopper 60 is provided outside the barrel 10, and the upper hopper 60 is connected to the feed port 11. The plastic raw material falls into the accommodating chamber from the feed port 11 and is extruded by the first screw 20 and the second screw 30. In the present embodiment, the accommodating chamber includes a first accommodating chamber 14 and a second accommodating chamber 15, both of which are cylindrical. The first accommodating chamber 14 is used to accommodate the first screw 20, and the second accommodating chamber 15 is used to accommodate the second screw 30. The diameter of the first accommodating chamber 14 is larger than the diameter of the second accommodating chamber 15. The first accommodating chamber 14 and the second accommodating chamber 15 are partially overlapped, so that a partial working section of the first screw 20 and a partial working section of the second screw 30 are meshed with each other to process the plastic.

[0037] In this embodiment, the extruder further includes a first meshing gear shaft 21 and a second meshing gear shaft 31. The first screw 20 is connected to the first meshing gear shaft 21, the second screw 30 is connected to the second meshing gear shaft 31, the first meshing gear shaft 21 and the second meshing gear shaft 31 are meshed with each other, and the first meshing gear shaft 21 is connected to the driving mechanism 40. In particular, to facilitate the replacement of different screws, in this embodiment, the extruder further includes a first coupling 201 and a second coupling 301, the first meshing gear shaft 21 is connected to the first screw 20 through the first coupling 201; the second meshing gear shaft 31 is connected to the second screw 30 through the second coupling 301. The first meshing gear shaft 21 and the second meshing gear shaft 31 are located between the discharge port 12 and the driving mechanism 40, that is, they are arranged outside the barrel 10, and in other embodiments, they can also be arranged inside the barrel 10. When the driving mechanism 40 drives the first meshing gear shaft 21 to rotate, the first screw 20 rotates along with the first meshing gear shaft 21, the first meshing gear shaft 21 drives the second meshing gear shaft 31 to rotate, and the second meshing gear shaft 31 drives the second screw 30 to rotate. In this embodiment, the first meshing gear shaft 21 and the second meshing gear shaft 31 are located outside the barrel 10. Such a setting can prevent the transmission between the two screws from being affected by the processing process in the barrel 10, thereby ensuring the stability of the screw transmission.

[0038] In this embodiment, the first screw 20 is provided with a feeding section 22, a compression section 23 and a mixing and plasticizing section 24 in sequence from the connection port 13 to the discharge port 12. The feeding thread of the feeding section 22 is an equidistant and gradual thread. The plastic raw material slides from the feed port 11 to between the threads of the feeding section, and then the first screw 20 is continuously rotated to drive the plastic raw material to move toward the discharge port 12. The end of the first screw 20 close to the connection port 13 is provided with a sealing thread 202 to prevent the material from flowing out.

[0039] In this embodiment, the second screw is provided with a second screw feeding section at a position corresponding to the feeding section of the first screw, and the second screw feeding section includes a feeding thread 331, a sealing thread 321 and a smooth rod portion 322. The length of the sealing thread does not need to be too long, as long as it can play a sealing role. A portion of the sealing section of the second screw 30 is provided with a sealing thread, and the other portion is a smooth rod. The setting of the sealing thread length in this embodiment can reduce the processing time of the sealing thread of the second screw 30. The working section of the second screw 30 from the connecting port 13 to the discharge port 12 is provided with a sealing section 32, a feeding section 33, a compression section 34 and a mixing and plasticizing section 35 in sequence.

[0040] In this embodiment, the first screw rod 20 and the second screw rod 30 each include a rotating rod and a plurality of threaded sleeves. Figure 5 As shown, the feeding section of the first screw rod 20 includes a plurality of threaded sleeves 252, the outer surface of the threaded sleeves 252 is provided with feeding threads, and the plurality of threaded sleeves 252 are sleeved outside the rotating rod 251, and the rotating rod 251 is connected to the first coupling 201. When the feeding threads are damaged, the fault can be eliminated by replacing the threaded sleeves 252 where the damaged feeding threads are located, thereby reducing the maintenance cost. The driving mechanism 40 drives the rotating rod 251 to rotate. In other embodiments, the first screw rod 20 and the second screw rod 30 both include a rotating rod and a feeding thread, and the feeding thread is an integral thread assembled on the rotating rod. The integral thread has an overall strength and has a better effect on the transmission of large torque.

[0041] In this embodiment, the compression section 23 of the first screw 20 and the second screw 30 and the mixing and plasticizing section 24 include a plurality of working blocks 253. Adjacent working blocks 253 in the compression section 23 are staggered at a certain angle so that the plurality of working blocks 253 in the compression section 23 are arranged in a spiral manner, and such an arrangement can effectively crush plastic particles. Adjacent working blocks in the mixing and plasticizing section 24 are staggered at 90°, and such an arrangement makes the working process more stable. In this embodiment, the working block is an elliptical flat block provided with a mounting hole 254, and the working block 253 is mounted outside the rotating rod 251 through the mounting hole 254.

[0042] The compression section and mixing and plasticizing section of the two screws are both trapezoidal double-start threads. In this embodiment, the driving mechanism 40 is a motor.

[0043] Preferably, the barrel of the extruder is provided with an inwardly protruding barrier portion 50, which is located between the sealing thread 321 and the polished rod portion 322 of the feeding section of the first screw 20 and the feeding section of the second screw 30. The barrier portion 50 can prevent the plastic from falling onto the polished rod portion of the second screw to avoid loss.

[0044] A twin-screw extruder of the present invention sets the diameter corresponding to the second screw to be smaller than the diameter corresponding to the first screw, so that the first screw can be driven by a driving mechanism to drive the second screw to rotate, avoiding the need for a reduction gearbox and reducing noise generated during operation.

[0045] Embodiment 2

[0046] See also Fig.10, the second screw may not be provided with a feeding section, such a setting makes the second screw not need to bear a large torsion force, so the diameter of the second screw can be set to be smaller than the diameter of the first screw. The second screw is provided with a sealing section at a position corresponding to the feeding section of the first screw, and a light rod portion 362 and a sealing thread 361 are sequentially provided from the connecting port to the discharge port. The barrel is provided with an inwardly protruding blocking portion 363, and the blocking portion 363 is located between the feeding section of the first screw and the sealing section of the second screw.

[0047] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "left", "right", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0048] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0050] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0051] The present invention is not limited to the above-mentioned embodiments. If various changes or modifications to the present invention do not depart from the spirit and scope of the present invention, and if these changes and modifications fall within the scope of the claims and equivalent technologies of the present invention, the present invention is also intended to include these changes and modifications.

Claims

1. A twin-screw extruder, characterized in that: The invention comprises a barrel, a first screw, a second screw and a driving mechanism; the barrel is provided with a containing cavity, and a side wall of the barrel is provided with a feed port connected to the containing cavity; the first screw and the second screw extend into the containing cavity, the first screw and the second screw are meshed with each other, and the driving mechanism is connected to the first screw and can drive the first screw to rotate; the first screw and the second screw are both provided with a working section, and the diameter of the working section of the second screw is different from the diameter of the working section corresponding to the first screw; The working section of the first screw includes a compression section and a mixing and plasticizing section; the working section of the second screw includes a compression section and a mixing and plasticizing section; The compression section and the mixing and plasticizing section both include a plurality of working blocks; Adjacent working blocks in the compression section are staggered at a certain angle so that the multiple working blocks in the compression section are arranged in a spiral manner; Adjacent working blocks in the mixing and plasticizing section are staggered by 90°. The working section of the first screw includes a feeding section, and the feeding section of the first screw has a feeding thread; The second screw has a polished rod portion and a sealing thread that are sequentially arranged along the connecting port toward the discharge port at a position corresponding to the feeding section of the first screw.

2. A twin-screw extruder according to claim 1, characterized in that: The diameter of the working section of the second screw is smaller than the diameter of the corresponding working section of the first screw.

3. A twin-screw extruder according to claim 1 or 2, characterized in that: It also includes a first meshing gear shaft and a second meshing gear shaft, wherein the first meshing gear shaft and the second meshing gear shaft mesh with each other; and the first meshing gear shaft is connected to the driving mechanism.

4. A twin-screw extruder according to claim 3, characterized in that: The first meshing gear shaft and the second meshing gear shaft are located outside the barrel.

5. A twin-screw extruder according to claim 3, characterized in that: It also includes a first coupling and a second coupling, wherein the first meshing gear shaft is connected to the first screw rod through the first coupling; and the second meshing gear shaft is connected to the second screw rod through the second coupling.

6. A twin-screw extruder according to claim 1, characterized in that: The second screw is further provided with a feeding thread at a position corresponding to the feeding section of the first screw, and the feeding thread is located downstream of the sealing thread along the direction from the connecting port to the discharge port.

7. A twin-screw extruder according to claim 6, characterized in that: The barrel is provided with an inwardly protruding barrier portion, and the barrier portion is located between the sealing threads and the polished rod portion of the first screw feeding section and the second screw feeding section.

8. A twin-screw extruder according to claim 1, characterized in that: The feeding section of the first screw includes a plurality of thread sleeve blocks.

9. A twin-screw extruder according to claim 1, characterized in that: The working block is an elliptical flat block provided with a mounting hole.

10. A twin-screw extruder according to claim 1, characterized in that: The accommodating chamber includes a first accommodating chamber and a second accommodating chamber, the first accommodating chamber is used to accommodate the first screw rod, and the second accommodating chamber is used to accommodate the second screw rod.

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