Twin-screw extruder for preparing polyethylene particles

Abstract

The invention discloses a double-screw extruder for preparing polyethylene particles, and relates to the technical field of double-screw extruders. The device comprises a machine base, a machine barrel is fixedly installed at the top of the machine base, a heater is installed on the outer side of the machine barrel, a first screw rod and a second screw rod are rotatably installed in the machine barrel and synchronously rotate in the same direction, the first screw rod is a single screw rod, and the second screw rod is a single screw rod. And the second screw rod consists of three groups of fixed screw rods, two groups of connecting rods and two groups of sliding screw rods. Through the arrangement of the three sets of fixed screw rods, the two sets of connecting rods and the two sets of sliding screw rods, the screw rods can be subjected to segmented modular machining, the machining processes do not affect one another, each segment of round rod is short, the fixed screw rods and the sliding screw rods can be completed through the same machining device, and the connecting rods are polished rods and can be used as size fine adjustment rods of the second screw rods; the high machining precision of the fixed screw and the sliding screw is not needed, the machining process can be greatly simplified, and the machining cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of twin-screw extruders, in particular to a twin-screw extruder for preparing polyethylene particles. Background Art

[0002] The process flow of polyethylene granule preparation is as follows: raw materials → batching → mixing → melt extrusion → cooling → drying → pelletizing → screening → packaging → inspection → qualified → storage. The melt extrusion mainly adopts a twin-screw extruder, which heats the polymer material to a molten state through the rotating screw and mixes it during the process to make the materials evenly mixed, ensuring the quality and consistency of the final product.

[0003] In the document (application number: CN202010699082.9), a screw and an extruder are disclosed, wherein the screw has a connecting portion connected to the extruder body, and a feeding portion, a homogenizing portion and a conveying portion arranged sequentially downstream of the connecting portion along the length direction of the screw. The screws used in this extruder and the existing extruders are mostly multi-helix screws. The multi-helix parts are set to enable the screw to meet the conveying and extrusion at different stages. In particular, the pelletizing zone and the mixing zone need to provide high cutting force, and a special spiral part needs to be set. However, the screws set by this method are sometimes processed with different spiral parts on a round bar, and when one of the spiral parts is processed incorrectly, the entire round bar will be scrapped, which is difficult to process. In addition, the spiral parts need to be combined on a shaft using a shaft key. Although this method is processed independently, different processing equipment is required to achieve it, and the size requirements of each part are high, and the processing cost is high. At the same time, during the long-term operation of the screw, due to the thermal plasticization, polymerization reaction of the material and the nature of the material itself, residues are easily accumulated on the surface and inside of the screw. If not cleaned in time, the residues will lead to a decrease in output, unstable product quality, and may even damage the equipment. Therefore, regular screw cleaning is essential to keep the equipment in normal working condition. The spiral part on the existing screw is relatively complex, and the screw needs to be disassembled and cleaned during cleaning, and different cleaning methods need to be adopted for different spiral parts, which is difficult to clean and takes a long time to clean. Summary of the invention

[0004] The purpose of the present invention is to solve the above problems and provide a twin-screw extruder for preparing polyethylene particles.

[0005] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0006] A twin-screw extruder for preparing polyethylene particles comprises a machine base, a barrel is fixedly installed on the top of the machine base, a heater is installed on the outside of the barrel, a first screw and a second screw are rotatably installed inside the barrel, the first screw and the second screw rotate synchronously in the same direction, and the first screw is a single screw;

[0007] The second screw is composed of three groups of fixed screws, two groups of connecting rods and two groups of sliding screws. The fixed screws and the sliding screws have the same spiral structure. Adjacent fixed screws are connected by connecting rods. The sliding screw is sleeved on the connecting rod. A guide column is fixedly installed on the end of the sliding screw away from the middle fixed screw. The guide column penetrates the edge fixed screw. A transmission plate is fixedly installed on the end of the guide column away from the sliding screw. A top spring is arranged between the transmission plate and the fixed screw. A push rod is fixedly installed on the end of the transmission plate away from the fixed screw. A transmission box is arranged at the left end of the barrel, and a head box is arranged at the right end of the barrel. The two groups of transmission plates are respectively located in the transmission box and the head box. Wave top plates are fixedly installed inside the transmission box and the head box, and the push rod touches the wave top plate.

[0008] The second screw can be axially restricted in the barrel, a top pressure hydraulic cylinder is fixedly installed on the transmission plate inside the transmission box, a feeding port is opened on the top of the barrel, a hopper is arranged on the top of the feeding port, and an extrusion head is arranged at the bottom of the right end of the barrel.

[0009] Furthermore, a transmission shaft is rotatably installed inside the transmission box, a driving wheel is fixedly installed on the outside of the transmission shaft, a transmission wheel 1 and a transmission wheel 2 are rotatably installed inside the transmission box, and the transmission wheel 1 and the transmission wheel 2 are respectively meshed on both sides of the driving wheel, a driven wheel 1 is provided at the left end of the first screw rod, and a driven wheel 2 is provided at the left end of the second screw rod, the driven wheel 1 is meshed with the transmission wheel 1, and the driven wheel 2 is meshed with the transmission wheel 2, and the transmission wheel 2 is a long gear shaft, and a driving motor is fixedly installed on the top of the machine base, and the driving motor is connected to the transmission shaft through a reducer.

[0010] Furthermore, a locking sleeve is rotatably installed on the right end of the second screw, a locking hole is opened on the outer side of the locking sleeve, a locking hydraulic cylinder is fixedly installed on the right end of the barrel, the locking hydraulic cylinder is located in the head box, the telescopic end of the locking hydraulic cylinder can be inserted into the locking hole, and a tension spring is arranged between the locking sleeve and the right end of the barrel.

[0011] Furthermore, a rotary joint is arranged at the left end of the top pressure hydraulic cylinder, a through hole is opened at the left end of the transmission box, and an external hydraulic pipeline is connected to the rotary joint through the through hole.

[0012] Furthermore, the wavelengths of the two groups of wave top plate waves are different.

[0013] Furthermore, the connecting rod is threadably connected to the fixing screw.

[0014] Furthermore, the guide column is threadably connected to the sliding screw.

[0015] Furthermore, the guide pillars are arranged in four groups.

[0016] Furthermore, sealing plates are fixedly mounted on both ends of the barrel by bolts.

[0017] The beneficial effects of the present invention are as follows:

[0018] 1. The present invention is composed of three groups of fixed screws, two groups of connecting rods and two groups of sliding screws through the setting of the second screw. During the operation of the equipment, under the action of the wave top plate and the top rod, the sliding screw slides back and forth, and the sliding distance is smaller than the spiral pitch of the first screw, thereby continuously changing the meshing pitch between the sliding screw and the first screw, which can increase the shear force at this position. It is suitable for the pelletizing area and the mixing area, and because the spiral parts are staggered with each other, the exhaust effect can be improved.

[0019] 2. The present invention arranges three groups of fixed screws, two groups of connecting rods and two groups of sliding screws, so that the screws can be processed in sections and modules, and the processing techniques do not affect each other. The round rod of each section is shorter, and the fixed screw and the sliding screw can be completed using the same processing equipment. The connecting rod is a bare rod and can be used as a size fine-tuning rod for the second screw. The high processing accuracy of the fixed screw and the sliding screw is not required, which can greatly simplify the processing technique and reduce the processing cost.

[0020] 3. In the present invention, the second screw can be dislocated relative to the first screw as a whole, so that the contact position of the first screw and the second screw is always changing, and the adhesive on their surfaces can be scraped off from each other, which is convenient for cleaning and has high cleaning efficiency. At the same time, when disassembling for cleaning, the second screw can be disassembled into small sections, which is more convenient for cleaning and maintenance, and the small sections can be replaced separately, with low maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0022] Figure 2 It is the overall exploded view of the present invention;

[0023] Figure 3 It is a schematic diagram of the cross-sectional structure of the barrel of the present invention;

[0024] Figure 4 It is a schematic diagram of the cross-sectional structure of the head box of the present invention;

[0025] Figure 5 is a schematic diagram of the first screw and the second screw of the present invention;

[0026] Figure 6 It is an exploded view of the second screw of the present invention.

[0027] 1. Machine base; 2. Machine barrel; 3. Extruder; 4. Transmission box; 41. Transmission shaft; 42. Driving wheel; 43. Transmission wheel one; 44. Transmission wheel two; 45. Wave top plate; 5. Head box; 51. Locking hydraulic cylinder; 6. First screw; 61. Driven wheel one; 7. Second screw; 71. Driven wheel two; 72. Locking sleeve; 73. Locking hole; 74. Fixed screw; 75. Connecting rod; 76. Sliding screw; 77. Guide column; 78. Transmission plate; 79. Push rod; 710. Push spring; 711. Push hydraulic cylinder; 712. Rotary joint; 713. Tension spring; 8. Heater; 9. Drive motor; 10. Hopper. DETAILED DESCRIPTION

[0028] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0029] Embodiment 1, as Figure 1-Figure 6 As shown, a twin-screw extruder for preparing polyethylene particles comprises a machine base 1, a barrel 2 is fixedly installed on the top of the machine base 1, a heater 8 is installed on the outside of the barrel 2, a first screw 6 and a second screw 7 are rotatably installed inside the barrel 2, the first screw 6 and the second screw 7 rotate synchronously in the same direction, and the first screw 6 is a single screw;

[0030] The second screw 7 is composed of three groups of fixed screws 74, two groups of connecting rods 75 and two groups of sliding screws 76. The fixed screws 74 and the sliding screws 76 have the same spiral structure. Adjacent fixed screws 74 are connected by connecting rods 75. The sliding screws 76 are sleeved on the connecting rods 75. A guide column 77 is fixedly installed on the end of the sliding screw 76 away from the middle fixed screw 74. The guide column 77 penetrates the edge fixed screw 74. A transmission plate 78 is fixedly installed on the end of the guide column 77 away from the sliding screw 76. A top spring 710 is arranged between the transmission plate 78 and the fixed screw 74. A push rod 79 is fixedly installed on the end of the transmission plate 78 away from the fixed screw 74. A transmission box 4 is arranged at the left end of the barrel 2, and a head box 5 is arranged at the right end of the barrel 2. The two groups of transmission plates 78 are respectively located in the transmission box 4 and the head box 5. The transmission box 4 and the head box 5 are fixedly installed with a wave top plate 45 inside, and the push rod 79 contacts the wave top plate 45.

[0031] The second screw 7 can be axially restricted in the barrel 2. A top pressure hydraulic cylinder 711 is fixedly installed on the transmission plate 78 inside the transmission box 4. A feeding port is opened at the top of the barrel 2. A hopper 10 is set at the top of the feeding port. An extrusion head 3 is set at the bottom of the right end of the barrel 2.

[0032] The first screw 6 is a single screw, and the spiral part set on the surface is single, which can be directly processed and formed on the equipment at one time. The second screw 7 is composed of three groups of fixed screws 74, two groups of connecting rods 75 and two groups of sliding screws 76. The fixed screws 74 and the sliding screws 76 are divided into small sections, which can also be processed and formed on the processing equipment of the first screw 6. The connecting rod 75 is a bare rod, which can be directly cut into the required length. At the same time, the deviation size of the fixed screw 74 and the sliding screw 76 can be eliminated by adjusting the length of the connecting rod 75 to eliminate the overall error of the second screw 7. Therefore, the screw used in the extruder of the present invention can be processed and formed on one equipment, and does not require high length accuracy, and the processing technology is simple;

[0033] The two sets of sliding screws 76 are respectively located in the pelletizing zone and the mixing zone. During processing, the raw materials enter the barrel 2 through the hopper 10, and the first screw 6 and the second screw 7 rotate synchronously. The second screw 7 drives the transmission plate 78 and the top rod 79 to rotate relative to the wave top plate 45. The transmission plate 78 reciprocates under the action of the wave top plate 45 and the top spring 710. The transmission plate 78 drives the sliding screw 76 to slide back and forth through the guide column 77, and the sliding spacing of the sliding screw 76 is smaller than the spiral spacing of the first screw 6. Therefore, under safe conditions, the sliding screw 76 slides relative to the first screw 6, and the meshing spacing between them always changes, which can greatly improve the shear force and meet the requirements of cutting and mixing. In addition, since the sliding screw 76 slides relative to the first screw 6, it can help to exhaust the pelletizing zone and the mixing zone, thereby improving the processing effect.

[0034] When the screw needs to be cleaned, the cleaning liquid is injected into the equipment through the feeding port, and then the second screw 7 is unlocked axially, and the top pressure hydraulic cylinder 711 is controlled to operate. The top pressure hydraulic cylinder 711 extends out and presses against the left end of the second screw 7. At this time, the equipment is started again. The distance between the transmission plate 78 on the left and the second screw 7 cannot be reduced under the restriction of the top pressure hydraulic cylinder 711. Therefore, under the action of the left wave top plate 45, the second screw 7 reciprocates relative to the first screw 6, and the sticky matter on its surface can be scraped off, which makes cleaning convenient. When the pollution is serious, the first screw 6 and the second screw 7 are removed. Since the spiral parts of the first screw 6 and the second screw 7 are the same, the same cleaning method can be used to quickly complete the cleaning. The second screw 7 can be disassembled into small sections, which is more convenient for cleaning and maintenance, and the small sections can be replaced individually, with low maintenance costs.

[0035] Furthermore, four groups of guide pillars 77 are provided to improve transmission stability.

[0036] Furthermore, both ends of the barrel 2 are fixedly mounted with blocking plates by bolts, and the transmission box 4 and the head box 5 are fixedly mounted on the blocking plates, so that the inside of the barrel 2 can be easily inspected and disassembled.

[0037] Embodiment 2, on the basis of the above embodiment, further includes: a transmission shaft 41 is rotatably installed inside the transmission box 4, a driving wheel 42 is fixedly installed on the outer side of the transmission shaft 41, a transmission wheel 1 43 and a transmission wheel 2 44 are rotatably installed inside the transmission box 4, the transmission wheel 1 43 and the transmission wheel 2 44 are respectively meshed on both sides of the driving wheel 42, a driven wheel 1 61 is provided at the left end of the first screw rod 6, a driven wheel 2 71 is provided at the left end of the second screw rod 7, the driven wheel 1 61 is meshed with the transmission wheel 1 43, the driven wheel 2 71 is meshed with the transmission wheel 2 44, the transmission wheel 2 44 is a long gear shaft, and a driving motor 9 is fixedly installed on the top of the machine base 1, and the driving motor 9 is connected to the transmission shaft 41 through a reducer.

[0038] The driving motor 9 drives the transmission shaft 41 to rotate, the transmission shaft 41 drives the driving wheel 42 to rotate, the driving wheel 42 drives the transmission wheel 1 43 and the transmission wheel 2 44 to rotate synchronously in the same direction, the transmission wheel 1 43 and the transmission wheel 2 44 rotate synchronously in the same direction through the driven wheel 1 61 and the driven wheel 2 71 respectively, the driven wheel 1 61 and the driven wheel 2 71 drive the first screw 6 and the second screw 7 to rotate synchronously in the same direction, and because the transmission wheel 2 44 is a long gear shaft, when the second screw 7 slides back and forth relative to the first screw 6, the driven wheel 2 71 can always mesh with the transmission wheel 2 44, and the transmission is stable.

[0039] Embodiment three, on the basis of the above embodiment, further includes: a locking sleeve 72 is rotatably installed on the right end of the second screw 7, a locking hole 73 is opened on the outer side of the locking sleeve 72, a locking hydraulic cylinder 51 is fixedly installed on the right end of the barrel 2, the locking hydraulic cylinder 51 is located in the head box 5, the telescopic end of the locking hydraulic cylinder 51 can be inserted into the locking hole 73, and a tension spring 713 is arranged between the locking sleeve 72 and the right end of the barrel 2.

[0040] During extrusion processing, the telescopic end of the locking hydraulic cylinder 51 is inserted into the locking hole 73, and the locking hydraulic cylinder 51 limits the axial movement of the locking sleeve 72. The locking sleeve 72 limits the axial movement of the second screw 7, but does not affect the rotation of the second screw 7. When the screw needs to be cleaned, the cleaning liquid is injected into the equipment through the feeding port, and then the telescopic end of the locking hydraulic cylinder 51 is controlled to be pulled out of the locking hole 73 to axially unlock the second screw 7, and the top pressure hydraulic cylinder 711 is controlled to run. The top pressure hydraulic cylinder 711 extends out and presses against the left end of the second screw 7. At this time, the equipment is started again. The distance between the transmission plate 78 on the left and the second screw 7 cannot be reduced under the limiting action of the top pressure hydraulic cylinder 711. Therefore, under the action of the left wave top plate 45 and the tension spring 713, the second screw 7 slides back and forth relative to the first screw 6, which can scrape off the sticky matter on its surface, making cleaning convenient.

[0041] Embodiment 4, based on the above embodiment, further includes: a rotary joint 712 is provided at the left end of the top pressure hydraulic cylinder 711, a through hole is opened at the left end of the transmission box 4, and the external hydraulic pipeline is connected to the rotary joint 712 through the through hole, so that the control of the top pressure hydraulic cylinder 711 does not affect the rotation of the second screw 7.

[0042] Embodiment 5, based on the above embodiment, further includes that the wavelengths of the waves of the two groups of wave top plates 45 are different, so that the reciprocating sliding frequencies of the two groups of sliding screws 76 are different, which is suitable for different processing requirements.

[0043] Embodiment 6, based on the above embodiment, further includes that the connecting rod 75 is threadedly connected to the fixed screw 74. Through this design, the overall length of the second screw 7 can be fine-tuned without changing the overall length of the connecting rod 75, which is more convenient to use.

[0044] Furthermore, the guide post 77 is threadedly connected to the sliding screw 76 .

[0045] The second screw rod 7 assembly steps are as follows: the sliding screw rod 76 is sleeved on the connecting rod 75, and then the connecting rod 75 is threadedly connected with the fixed screw rod 74, and then the guide column 77 is passed through the fixed screw rod 74 and threaded onto the sliding screw rod 76, which is convenient for assembly.

[0046] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A twin-screw extruder for preparing polyethylene particles, comprising a base (1), characterized in that: A barrel (2) is fixedly mounted on the top of the machine base (1), a heater (8) is mounted on the outside of the barrel (2), a first screw (6) and a second screw (7) are rotatably mounted inside the barrel (2), the first screw (6) and the second screw (7) rotate synchronously in the same direction, and the first screw (6) is a single screw; The second screw rod (7) is composed of three groups of fixed screw rods (74), two groups of connecting rods (75) and two groups of sliding screw rods (76). The fixed screw rods (74) and the sliding screw rods (76) have the same spiral structure. Adjacent fixed screw rods (74) are connected by connecting rods (75). The sliding screw rods (76) are sleeved on the connecting rods (75). A guide column (77) is fixedly installed at one end of the sliding screw rod (76) away from the middle fixed screw rod (74). The guide column (77) passes through the edge fixed screw rod (74). The end of the guide column (77) away from the sliding screw rod (76) A transmission plate (78) is fixedly installed, a top spring (710) is arranged between the transmission plate (78) and the fixed screw (74), a top rod (79) is fixedly installed on one end of the transmission plate (78) away from the fixed screw (74), a transmission box (4) is arranged at the left end of the barrel (2), a head box (5) is arranged at the right end of the barrel (2), two sets of transmission plates (78) are respectively located in the transmission box (4) and the head box (5), and a wave top plate (45) is fixedly installed inside the transmission box (4) and the head box (5), and the top rod (79) and the wave top plate (45) are in contact with each other; The second screw (7) can be axially restricted in the barrel (2); a top pressure hydraulic cylinder (711) is fixedly installed on the transmission plate (78) inside the transmission box (4); a feeding port is opened at the top of the barrel (2); a hopper (10) is arranged at the top of the feeding port; and an extrusion head (3) is arranged at the bottom of the right end of the barrel (2).

2. A twin-screw extruder for preparing polyethylene particles according to claim 1, characterized in that: A transmission shaft (41) is rotatably mounted inside the transmission box (4), a driving wheel (42) is fixedly mounted outside the transmission shaft (41), a driving wheel 1 (43) and a driving wheel 2 (44) are rotatably mounted inside the transmission box (4), the driving wheel 1 (43) and the driving wheel 2 (44) are respectively meshed on both sides of the driving wheel (42), a driven wheel 1 (61) is arranged at the left end of the first screw rod (6), a driven wheel 2 (71) is arranged at the left end of the second screw rod (7), the driven wheel 1 (61) is meshed with the transmission wheel 1 (43), the driven wheel 2 (71) is meshed with the transmission wheel 2 (44), the transmission wheel 2 (44) is a long gear shaft, a driving motor (9) is fixedly mounted on the top of the machine base (1), and the driving motor (9) is connected to the transmission shaft (41) through a reducer.

3. A twin-screw extruder for preparing polyethylene particles according to claim 1, characterized in that: A locking sleeve (72) is rotatably mounted on the right end of the second screw rod (7), and a locking hole (73) is provided on the outer side of the locking sleeve (72). A locking hydraulic cylinder (51) is fixedly mounted on the right end of the barrel (2), and the locking hydraulic cylinder (51) is located in the head box (5). The telescopic end of the locking hydraulic cylinder (51) can be inserted into the locking hole (73), and a tension spring (713) is provided between the locking sleeve (72) and the right end of the barrel (2).

4. A twin-screw extruder for preparing polyethylene particles according to claim 3, characterized in that: The left end of the top pressure hydraulic cylinder (711) is provided with a rotary joint (712), and the left end of the transmission box (4) is provided with a through hole, and the external hydraulic pipeline is connected to the rotary joint (712) through the through hole.

5. A twin-screw extruder for preparing polyethylene particles according to claim 1, characterized in that: The wavelengths of the waves of the two groups of wave top plates (45) are different.

6. A twin-screw extruder for preparing polyethylene particles according to claim 1, characterized in that: The connecting rod (75) is threadedly connected to the fixing screw rod (74).

7. A twin-screw extruder for preparing polyethylene particles according to claim 6, characterized in that: The guide column (77) is threadedly connected to the sliding screw (76).

8. A twin-screw extruder for preparing polyethylene particles according to claim 7, characterized in that: The guide pillars (77) are arranged in four groups.

9. A twin-screw extruder for preparing polyethylene particles according to claim 1, characterized in that: Both ends of the barrel (2) are fixed with blocking plates by means of bolts.

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