A twin-screw extruder

Abstract

The application discloses a double-screw extruder, the first screw monomer and the second screw monomer are of the same structure, the first screw monomer comprises a first main shaft, the first main shaft is provided with a first upstream conveying assembly, a first mixing assembly, a first kneading assembly, a first pressure kneading assembly and a first downstream conveying assembly in sequence through a spline sleeve in a conveying direction, and a corresponding second main shaft is provided with a second upstream conveying assembly, a second mixing assembly, a second kneading assembly, a second pressure kneading assembly and a second downstream conveying assembly in sequence through a spline sleeve in the conveying direction; an air extraction window is further arranged on the barrel, an air extraction box body is fixed to the barrel, an air extraction connector which is communicated with a negative pressure air extraction device is arranged on the air extraction box body, and a material cleaning device which is used for cleaning plastic adhered to the air extraction window is arranged in the air extraction box body; the extruder can better shear and disperse plastic raw materials, reduces the generation of impurities, and can conveniently clean the adhered plastic while air extraction.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of screw extruders in plastic particle forming, in particular to a double-screw extruder. BACKGROUND

[0002] In the production process of thermoplastic plastics, a double-screw extruder is needed, and the structure of the double-screw extruder mainly comprises a barrel, a feeding hopper is arranged at one end of the barrel, the other end is a discharge port, a heating device is arranged outside the barrel to heat the plastic inside the barrel, a first screw monomer and a second screw monomer rotating in the same direction are rotatably installed in the barrel, the first screw monomer and the second screw monomer are the same in structure and are meshed with each other, wherein the first screw monomer is provided with an upstream conveying thread segment, a mixing thread segment, a kneading thread segment and a downstream conveying thread segment, the raw material is conveyed through the upstream conveying thread segment and then enters the mixing thread segment for mixing, and the mixed raw material is sheared and dispersed in the kneading thread segment, and then extruded through the downstream conveying thread segment, and the screw design of the current double-screw extruder is not reasonable, and the main problem is the kneading thread segment, the kneading thread segment mainly comprises kneading teeth arranged at 90°, the spacing between the end of the kneading tooth and the inner hole of the barrel is relatively small and completely the same, the kneading tooth shears the plastic while dispersing the filler in the plastic when rotating, but since the spacing is small and always the same, the plastic is pressed tightly against the barrel, so this part of the plastic is continuously heated, which causes the heating temperature to be too high, thereby causing the final extruded plastic melt to contain black impurities after pelletizing; and the barrel is provided with an air suction port connected to an air suction pipe, and since some plastic particles have relatively high viscosity, the plastic particles may adhere to the air suction port due to the suction force of the air suction port during long-term use, which reduces the area of the suction port, thereby affecting the air suction efficiency, and the adhered plastic is also difficult to clean. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a double-screw extruder which can better shear and disperse plastic raw materials, reduce the generation of impurities, and facilitate the cleaning of adhered plastic while air suction.

[0004] To solve the above technical problems, the technical scheme of the present application is: a double-screw extruder, comprising a machine base, a barrel fixed on the machine base, a first screw monomer and a second screw monomer rotatably installed in the barrel, a rotary power device fixed on the machine base for driving the first screw monomer and the second screw monomer to rotate in the same direction, a feeding port provided at the upstream end of the barrel, a feeding device provided at the feeding port, an extrusion die fixed at the lower end of the barrel, the first screw monomer and the second screw monomer having the same structure, the first screw monomer comprising a first main shaft, the first main shaft being provided with, in sequence in the conveying direction, a first upstream conveying assembly, a first mixing assembly, a first kneading assembly, a first pressure kneading assembly and a first downstream conveying assembly, and the corresponding second main shaft being provided with, in sequence in the conveying direction, a second upstream conveying assembly, a second mixing assembly, a second kneading assembly, a second pressure kneading assembly and a second downstream conveying assembly;

[0005] wherein the first upstream conveying assembly and the second upstream conveying assembly have the same structure, the first upstream conveying assembly comprising a first upstream conveying threaded sleeve and the second upstream conveying assembly comprising a second upstream conveying threaded sleeve, the first upstream conveying threaded sleeve and the second upstream conveying threaded sleeve being engaged with each other;

[0006] the first mixing assembly comprising a first mixing threaded sleeve and the second mixing assembly comprising a second mixing threaded sleeve, the first mixing threaded sleeve and the second mixing threaded sleeve being engaged with each other, the pitch of the second mixing threaded sleeve being smaller than the pitch of the first upstream conveying threaded sleeve;

[0007] the first kneading assembly comprising a first kneading sleeve body, the first kneading sleeve body being fitted on the first main shaft through a spline, the first kneading sleeve body being provided with a plurality of kneading teeth that are staggered at an interval of 90°, the tooth surface of the kneading teeth being perpendicular to the axis of the first kneading sleeve body, the diameter of the contour circle where the outer end of each kneading tooth is located gradually decreasing in the conveying direction, the second kneading assembly having the same structure as the first kneading assembly, the kneading teeth on the second kneading assembly being engaged with the kneading teeth on the first kneading assembly;

[0008] the first pressure kneading assembly comprising a first pressure kneading sleeve body, the first pressure kneading sleeve body being fitted on the first main shaft through a spline, the first pressure kneading sleeve body being provided with a plurality of pressure engaging teeth that are spaced apart, the stagger angle of the pressure engaging teeth being less than 90°, the diameter of the contour circle where the outer end of each pressure engaging tooth is located gradually decreasing in the conveying direction, the tooth surface of the pressure engaging teeth being perpendicular to the axis of the first kneading sleeve body, the second pressure kneading assembly having the same structure as the first pressure kneading assembly, the pressure engaging teeth on the second pressure kneading assembly being engaged with the pressure engaging teeth on the first pressure kneading assembly;

[0009] The structure of the first downstream conveying assembly is the same as that of the first upstream conveying assembly, and the structure of the second downstream conveying assembly is the same as that of the second upstream conveying assembly.

[0010] The cartridge is further provided with an air extraction window, and an air extraction box body is fixed to the cartridge at the air extraction window; the air extraction box body is provided with an air extraction joint in communication with a negative pressure air extraction device; and the air extraction box body is provided with a material cleaning device for cleaning plastic adhered to the air extraction window.

[0011] As a preferred solution, the material cleaning device comprises a material cleaning block vertically and liftly installed in the air extraction box body, the material cleaning block is coated with a polytetrafluoroethylene coating, the shape of the material cleaning block is adapted to the shape of the air extraction window, the material cleaning block is driven by a vertical lifting power device to be inserted into the air extraction window from top to bottom, and the material cleaning block is separated from the air extraction window when being at the uppermost position.

[0012] As a preferred solution, the air extraction box body is fixed with a mounting plate, the upper end of the material cleaning block is fixed with at least two guide rods, the material cleaning block is vertically and slidably installed on the mounting plate through the guide rods, a compression spring is sleeved on the guide rod and arranged between the material cleaning block and the mounting plate, and the vertical lifting power device is fixed on the mounting plate.

[0013] As a preferred solution, the vertical lifting power device comprises a linear power device fixed on the mounting plate and horizontally arranged, a driving block is fixed on the power end of the linear power device, the upper end of the driving block is provided with an inclined driving slope, a vertical strip-shaped hole matched with the driving slope of the driving block is arranged on one of the guide rods, and a limiting structure limiting the lower limit position of the material cleaning block is arranged on the other guide rod.

[0014] As a preferred solution, the vertical lifting power device comprises a swing fulcrum fixed on the mounting plate, a driving swing lever is swingly installed on the swing fulcrum, the swing fulcrum divides the driving swing lever into a short arm and a long arm, the upper end of one of the guide rods is provided with a horizontal strip-shaped hole, a movable pin shaft is hingedly connected to the long arm and inserted into the horizontal strip-shaped hole, and a vertical driving cylinder is further fixed on the mounting plate, the piston rod of the vertical driving cylinder is downwardly arranged and abuts against the short arm.

[0015] As a preferred solution, the stagger angle of the pressurized engagement teeth is 60°.

[0016] As a preferred solution, at least one of the intervals between the kneading teeth of the first kneading assembly is different from the others.

[0017] As a preferred scheme, the threads of the first mixed thread sleeve are provided with radially extending grooves.

[0018] As a preferred scheme, the number of the first kneading assemblies is one or more, and the number of the first pressurized kneading assemblies is one or more.

[0019] After the above technical scheme is adopted, the effect of the present application is as follows: a double-screw extruder, comprising a machine base, a barrel fixed on the machine base, a first screw monomer and a second screw monomer rotatably installed in the barrel, a rotating power device fixed on the machine base for driving the first screw monomer and the second screw monomer to rotate in the same direction, a feeding port provided at the upstream end of the barrel, a feeding device provided at the feeding port, an extrusion die fixed at the lower end of the barrel, the first screw monomer and the second screw monomer being identical in structure, the first screw monomer comprising a first main shaft, the first main shaft being provided with, in sequence in the conveying direction, a first upstream conveying assembly, a first mixing assembly, a first kneading assembly, a first pressurized kneading assembly and a first downstream conveying assembly, and the corresponding second main shaft being provided with, in sequence in the conveying direction, a second upstream conveying assembly, a second mixing assembly, a second kneading assembly, a second pressurized kneading assembly and a second downstream conveying assembly;

[0020] wherein the first upstream conveying assembly and the second upstream conveying assembly are identical in structure, the first upstream conveying assembly comprising a first upstream conveying thread sleeve and the second upstream conveying assembly comprising a second upstream conveying thread sleeve, the first upstream conveying thread sleeve and the second upstream conveying thread sleeve being engaged with each other;

[0021] the first mixing assembly comprising a first mixing thread sleeve and the second mixing assembly comprising a second mixing thread sleeve, the first mixing thread sleeve and the second mixing thread sleeve being engaged with each other, the pitch of the second mixing thread sleeve being smaller than the pitch of the first upstream conveying thread sleeve;

[0022] the first kneading assembly comprising a first kneading sleeve body, the first kneading sleeve body being provided with a plurality of kneading teeth that are staggered and spaced at intervals of 90°, the tooth surface of each kneading tooth being perpendicular to the axis of the first kneading sleeve body, the contour circle in which the outer end of each kneading tooth is located gradually decreasing in diameter in the conveying direction, the second kneading assembly being identical in structure to the first kneading assembly, the kneading teeth on the second kneading assembly being engaged with the kneading teeth on the first kneading assembly;

[0023] The first pressurized kneading assembly comprises a first pressurized kneading sleeve body which is sleeved on the first main shaft by spline, and a plurality of spaced pressurized engaging teeth are arranged on the first pressurized kneading sleeve body, the stagger angle of the pressurized engaging teeth is less than 90°, the diameter of the contour circle where the outer end of each pressurized engaging tooth is located gradually decreases in the conveying direction, and the tooth surface of the pressurized engaging teeth is perpendicular to the axis of the first kneading sleeve body; the structure of the second pressurized kneading assembly is the same as that of the first pressurized kneading assembly, and the pressurized engaging teeth on the second pressurized kneading assembly are engaged with the pressurized engaging teeth on the first pressurized kneading assembly;

[0024] The structure of the first downstream conveying assembly is the same as that of the first upstream conveying assembly, and the structure of the second downstream conveying assembly is the same as that of the second upstream conveying assembly;

[0025] The barrel is also provided with an air extraction window, an air extraction box body is fixed on the barrel at the air extraction window, an air extraction connector which communicates with the negative pressure air extraction device is arranged on the air extraction box body, and a material cleaning device which cleans the plastic adhered to the air extraction window is arranged in the air extraction box body; first, the plastic raw material enters the barrel through the feeding port, then the feeding device controls the plastic raw material to feed, then the first upstream conveying assembly and the second upstream conveying assembly and the first mixing assembly and the second mixing assembly extrude and convey the plastic raw material to ensure smooth plastic conveying, a plurality of kneading teeth which are staggered at 90° and spaced are arranged to shear and disperse, the diameter of the contour circle where the outer end of each kneading tooth is located gradually decreases in the conveying direction, which can facilitate the smooth passage of plastic through this area, especially to avoid the plastic staying on the barrel wall for a long time to cause high temperature; in addition, the stagger angle of the pressurized engaging teeth is less than 90°, and the diameter of the contour circle where the outer end of each pressurized engaging tooth is located gradually decreases in the conveying direction, so that the flow resistance of the plastic in this area can be increased by the pressurized engaging teeth, thereby further controlling and prolonging the shearing and dispersing time while increasing the distance between the pressurized engaging teeth and the inside of the barrel, ensuring the shearing and dispersing effect of the plastic raw material and reducing the generation of impurities; then the material cleaning device cleans the plastic adhered to the air extraction window, and then the air inside the barrel is extracted through the air extraction connector, so that the plastic adhered to the air extraction window can be cleaned while the air is extracted.

[0026] In addition, the material cleaning device comprises a material cleaning block which is vertically lifted and installed in the air extraction box body, the material cleaning block is coated with a polytetrafluoroethylene coating, the shape of the material cleaning block is matched with the shape of the air extraction window, the material cleaning block is driven by the vertical lifting power device to be inserted into the air extraction window from top to bottom, and the material cleaning block is separated from the air extraction window when it is at the uppermost position; since the shape of the material cleaning block is matched with that of the air extraction window, the plastic adhered to the air extraction window can be extruded and cleaned, which is simple and fast.

[0027] Further, the installation plate is fixed on the suction box, the upper end of the cleaning block is fixed with at least two guide rods, the cleaning block is vertically slidably installed on the installation plate through the guide rods, a compression spring is sleeved on the guide rods and arranged between the cleaning block and the installation plate, and the vertical lifting power device is fixed on the installation plate. The vertical lifting power device can drive the cleaning block to ascend, and the cleaning block can cooperate with the installation plate to compress the compression spring. When the cleaning block descends, the compression spring can accelerate the descending speed, so that the material attachments can be quickly cleaned, and the cleaning effect is improved.

[0028] Further, the vertical lifting power device comprises a linear power device fixed on the installation plate and horizontally arranged, a driving block is fixed on the power end of the linear power device, the upper end of the driving block is provided with an inclined driving slope, one of the guide rods is provided with a vertical strip-shaped hole matched with the driving slope of the driving block, and the other guide rod is provided with a limiting structure limiting the limit position of the cleaning block.

[0029] Further, the vertical lifting power device comprises a swing fulcrum fixed on the installation plate, a driving swing rod is swingably installed on the swing fulcrum, the swing fulcrum divides the driving swing rod into a short arm and a long arm, the upper end of one of the guide rods is provided with a horizontal strip-shaped hole, a movable pin shaft is hingedly connected to the long arm, the movable pin shaft is inserted into the horizontal strip-shaped hole, and a vertical driving cylinder is further fixed on the installation plate, the piston rod of the vertical driving cylinder is downwardly arranged and abuts against the short arm. The up-down swing of the short arm can be controlled through the extension and retraction of the piston of the vertical cylinder, so that the long arm swings up and down, the movable pin shaft moves horizontally in the horizontal strip-shaped hole, the guide rod ascends and descends, the cleaning block can effectively ascend and descend, and the structure is simple and reliable.

[0030] Further, the stagger angle of the pressure engaging teeth is 60°, so that the flow resistance of the plastic in the region between the pressure engaging teeth can be effectively increased, the plastic can be more uniformly sheared and dispersed, and the flow resistance is prevented from being too large and the conveying speed from being slow to affect the processing efficiency.

[0031] Further, at least one spacing between the kneading teeth of the first kneading assembly is different from the other spacings, so that the plastic can flow between the kneading teeth, the shearing and dispersing effect is effectively improved, and the plastic can be accurately and effectively conveyed.

[0032] Further, the thread of the first mixing thread sleeve is provided with a radially extending groove, so that the shearing effect can be effectively increased, the corresponding conveying effect can be maintained, and the production quality of the plastic shearing and dispersing is improved.

[0033] And since the number of the first kneading assembly is one or more, the number of the first pressurized kneading assembly is one or more; the more the number of the first kneading assembly and the first pressurized kneading assembly, the better the shearing and dispersing effect on the plastic, and the production quality is effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0034] The application will be further described below in combination with the drawings and examples.

[0035] Figure 1 is a perspective view of an embodiment of the application;

[0036] Figure 2 is a structural schematic view of a first screw monomer and a second screw monomer of an embodiment of the application;

[0037] Figure 3 is a half sectional view of a first screw monomer and a second screw monomer of an embodiment of the application;

[0038] Figure 4 is a structural schematic view of a first kneading assembly, a first pressurized kneading assembly, a second kneading assembly and a second pressurized kneading assembly of an embodiment of the application;

[0039] Figure 5 is a structure in a suction box of an embodiment of the application;

[0040] Figure 6 is another structure in a suction box of an embodiment of the application;

[0041] In the drawings: 1, machine base; 2, feeding port; 3, feeding device; 4, extrusion die; 5, rotary motor; 6, barrel; 7, first main shaft; 8, second main shaft; 9, spline; 10, first upstream conveying threaded sleeve; 11, second upstream conveying threaded sleeve; 12, first mixing threaded sleeve; 13, second mixing threaded sleeve; 14, first kneading sleeve body; 15, kneading tooth; 16, second kneading sleeve body; 17, first pressurized kneading sleeve body; 18, pressurized kneading tooth; 19, second pressurized kneading sleeve body; 20, first downstream conveying threaded sleeve; 21, second downstream conveying threaded sleeve; 22, groove; 23, suction window; 24, suction box; 25, horizontal linear air cylinder; 26, suction joint; 27, cleaning block; 28, mounting plate; 29, guide rod; 30, compression spring; 31, driving block; 32, driving inclined surface; 33, vertical strip-shaped hole; 34, limiting nut; 35, swing fulcrum; 36, driving swing lever; 37, horizontal strip-shaped hole; 38, movable pin; 39, vertical driving air cylinder; 40, driving roller. DETAILED DESCRIPTION

[0042] The application will be further described below in combination with the drawings and examples.

[0043] AsFigures 1 to 6 As shown in the figure, a double-screw extruder comprises a base 1, a barrel 6 fixed on the base 1, a first screw monomer and a second screw monomer rotatably installed in the barrel 6, a rotating power device fixed on the base 1 for driving the first screw monomer and the second screw monomer to rotate in the same direction, a feeding port 2 arranged at the upstream end of the barrel 6, a feeding device 3 arranged at the feeding port 2, an extrusion die 4 fixed at the lower end of the barrel 6, the first screw monomer and the second screw monomer having the same structure, the first screw monomer comprising a first main shaft 7, the first main shaft 7 being sleeved with a first upstream conveying assembly, a first mixing assembly, a first kneading assembly, a first pressure kneading assembly and a first downstream conveying assembly in sequence in the conveying direction through a spline 9, and the corresponding second main shaft 8 being sleeved with a second upstream conveying assembly, a second mixing assembly, a second kneading assembly, a second pressure kneading assembly and a second downstream conveying assembly in sequence in the conveying direction through the spline 9;

[0044] wherein the first upstream conveying assembly and the second upstream conveying assembly have the same structure, the first upstream conveying assembly comprising a first upstream conveying threaded sleeve 10 and the second upstream conveying assembly comprising a second upstream conveying threaded sleeve 11, the first upstream conveying threaded sleeve 10 and the second upstream conveying threaded sleeve 11 being engaged with each other;

[0045] the first mixing assembly comprising a first mixing threaded sleeve 12 and the second mixing assembly comprising a second mixing threaded sleeve 13, the first mixing threaded sleeve 12 and the second mixing threaded sleeve 13 being engaged with each other, the pitch of the second mixing threaded sleeve 13 being smaller than the pitch of the first upstream conveying threaded sleeve 10;

[0046] the first kneading assembly comprising a first kneading sleeve body 14, the first kneading sleeve body 14 being sleeved on the first main shaft 7 through the spline 9, the first kneading sleeve body 14 being provided with a plurality of kneading teeth 15 staggered and spaced at intervals at an angle of 90°, the tooth surface of the kneading teeth 15 being perpendicular to the axis of the first kneading sleeve body 14, the contour circle where the outer end of each kneading tooth 15 is located gradually decreasing in diameter in the conveying direction, the second kneading assembly having the same structure as the first kneading assembly, the kneading teeth 15 on the second kneading assembly being engaged with the kneading teeth 15 on the first kneading assembly, the second kneading assembly comprising a second engaging sleeve body 16;

[0047] The first pressurized kneading assembly comprises a first pressurized kneading sleeve 17 which is sleeved on the first main shaft 7 through the spline 9, and a plurality of pressurized engaging teeth 18 are arranged on the first pressurized kneading sleeve 17, the stagger angle of the pressurized engaging teeth 18 is less than 90°, the diameter of the contour circle where the outer end of each pressurized engaging tooth 18 is located gradually decreases in the conveying direction, and the tooth surface of the pressurized engaging tooth 18 is perpendicular to the axis of the first kneading sleeve 14; the structure of the second pressurized kneading assembly is the same as that of the first pressurized kneading assembly, the pressurized engaging teeth 18 on the second pressurized kneading assembly are engaged with the pressurized engaging teeth 18 on the first pressurized kneading assembly; the second pressurized engaging assembly comprises a second pressurized engaging sleeve 19;

[0048] The structure of the first downstream conveying assembly is the same as that of the first upstream conveying assembly, and the structure of the second downstream conveying assembly is the same as that of the second upstream conveying assembly;

[0049] The feeding device 3 first puts the plastic raw material from the feeding port 2, and the first screw monomer and the second screw monomer can be driven to rotate in the same direction by the rotating power device, which comprises a rotating motor 5 installed on the base 1 to drive the first main shaft 7 and the second main shaft 8 to rotate in the same direction. The first upstream conveying threaded sleeve 10 and the second upstream conveying threaded sleeve 11 can first convey and preliminarily extrude the plastic at the beginning stage, so as to preliminarily disperse the plastic, and then the first mixing threaded sleeve 12 and the second mixing threaded sleeve 13 further extrude and disperse the plastic on the basis of the foregoing, while slowing down the conveying speed. Then the plastic is further sheared and dispersed uniformly by the plurality of kneading teeth 15 arranged at intervals and staggered at 90°, and the diameter of the contour circle where the outer end of each kneading tooth 15 is located gradually decreases in the conveying direction, so that the plastic can smoothly pass through this area, especially to avoid the plastic staying on the wall of the barrel 6 for a long time to cause the temperature to be too high. In addition, the stagger angle of the pressurized engaging teeth 18 is less than 90°, and the diameter of the contour circle where the outer end of each pressurized engaging tooth 18 is located gradually decreases in the conveying direction, so that the flow resistance of the plastic in this area can be increased by the pressurized engaging teeth 18. In this way, while the distance between the pressurized engaging teeth 18 and the inside of the barrel 6 is increased, the shearing and dispersing time is further controlled and prolonged, the shearing and dispersing effect of the plastic raw material is ensured, and the generation of impurities is reduced. Finally, the sheared and dispersed plastic is conveyed out by the first downstream conveying assembly and the second downstream conveying assembly. The first downstream conveying assembly comprises a first downstream conveying threaded sleeve 20, and the second downstream conveying assembly comprises a second downstream conveying threaded sleeve 21. The first downstream conveying threaded sleeve 20 and the second downstream conveying threaded sleeve 21 are the same as the first upstream conveying threaded sleeve 10 and the second upstream conveying threaded sleeve 11 to extrude and convey the sheared and dispersed plastic out.

[0050] The material cylinder 6 is also provided with an air extraction window 23. An air extraction box 24 is fixed on the material cylinder 6 at the air extraction window 23. An air extraction connector 26 connected to a negative pressure air extraction device is provided on the air extraction box 24. A cleaning device is provided inside the air extraction box 24 to clean the plastic adhering to the air extraction window 23. The plastic adhering to the air extraction window 23 is cleaned by the cleaning device, and then the air is extracted from the inside of the material cylinder 6 through the air extraction connector 26.

[0051] like Figure 5 As shown, the cleaning device includes a cleaning block 27 vertically and vertically installed inside the suction box 24. The cleaning block 27 is coated with polytetrafluoroethylene. The shape of the cleaning block 27 is adapted to the shape of the suction window 23. The cleaning block 27 is driven by a vertical lifting power device to be inserted into the suction window 23 from top to bottom. When the cleaning block 27 is in the uppermost position, it is detached from the suction window 23. Because the cleaning block is adapted to the shape of the suction window 23, the plastic adhering to the suction window 23 can be squeezed and cleaned, which is simple and quick. Furthermore, when the cleaning block 27 is in the uppermost position, it is detached from the suction window 23, which facilitates suction after cleaning.

[0052] Furthermore, an installation plate 28 is fixed on the suction box 24, and at least two guide rods 29 are fixed to the upper end of the cleaning block 27. The cleaning block 27 is vertically slidably mounted on the installation plate 28 via the guide rods 29. A compression spring 30 is fitted on the guide rod 29, and the compression spring 30 is disposed between the cleaning block 27 and the installation plate 28. The vertical lifting power device is fixed on the installation plate 28. The vertical lifting power device can drive the cleaning block 27 to rise, and the cleaning block 27 can cooperate with the installation plate 28 to compress the compression spring 30. When the cleaning block 27 descends, the compression spring 30 can accelerate the descent speed to quickly clean the material attachments and improve the cleaning effect. The guide rods 29 can ensure the stability of the lifting of the cleaning block 27 and ensure its use.

[0053] In this embodiment, the vertical lifting power device includes a linear power device fixed to the mounting plate 28 and arranged horizontally. A drive block 31 is fixed to the power end of the linear power device. An inclined drive ramp 32 is provided at the upper end of the drive block 31. A vertical strip hole 33 is provided on one of the guide rods 29 to cooperate with the drive ramp 32 of the drive block 31. A limiting structure is provided on the other guide rod 29 to limit the descent limit position of the cleaning block 27. The linear power device drives the drive block 31 to move linearly, which in turn drives the guide rod 29 to rise and fall by cooperating with the vertical strip hole 33. The drive ramp 32 can slowly push up the vertical strip hole 33, thereby controlling the compression of the compression spring 30. At the same time, the limiting structure can prevent the cleaning block 27 from falling too far, ensuring the effect of use. The linear power device is a horizontal linear cylinder 25, which drives the drive block 31 to move horizontally.

[0054] Further, the limiting structure is a limiting nut 34 fixed on the guide rod 29, when the limiting nut 34 is in contact with the upper surface of the mounting plate 28, the upper end of the vertical strip-shaped hole 33 is higher than the upper surface of the mounting plate 28; so that when the driving block 31 moves, it can be effectively inserted into the vertical strip-shaped hole 33 to make the cleaning block 27 rise, ensuring the use effect.

[0055] As shown in Figure 6 , the vertical lifting power device includes a swing pivot 35 fixed on the mounting plate 28, a driving swing rod 36 is swingingly mounted on the swing pivot 35, the swing pivot 35 divides the driving swing rod 36 into a short arm and a long arm, the upper end of one of the guide rods 29 is provided with a horizontal strip-shaped hole 37, a movable pin shaft 38 is hingedly connected to the long arm, the movable pin shaft 38 is inserted into the horizontal strip-shaped hole 37, a vertical driving cylinder 39 is also fixed on the mounting plate 28, the piston rod of the vertical driving cylinder 39 is downwardly arranged and abuts against the short arm; the up-and-down swing of the short arm can be controlled by the extension and retraction of the piston of the vertical cylinder, so that the long arm swings up and down, the movable pin shaft 38 moves horizontally in the horizontal strip-shaped hole 37, so that the guide rod 29 rises and falls, and the cleaning block 27 can effectively rise and fall, the structure is simple and reliable.

[0056] Further, the piston rod of the vertical driving cylinder 39 is provided with a driving roller 40; so that it can flexibly contact with the short arm, reduce friction and improve efficiency.

[0057] In the embodiment, the stagger angle of the pressurizing engagement teeth 18 is 60°, the smaller the stagger angle, the better the shearing dispersion effect, so that the flow resistance of the plastic in the region between the pressurizing engagement teeth 18 can be effectively increased, the plastic can be more uniformly sheared and dispersed, and the flow resistance is avoided from being too large and the conveying speed is avoided from being too slow to affect the processing efficiency.

[0058] Further, at least one of the intervals between the kneading teeth 15 of the first kneading assembly is not equal to the other intervals; so that the plastic can flow between the engagement teeth, the shearing dispersion effect can be effectively improved, and the plastic can be accurately and effectively conveyed.

[0059] As shown in Figure 2 , the thread of the first mixing threaded sleeve 12 is provided with a radially extending groove 22; so that the shearing capacity of the first mixing threaded sleeve 12 is effectively improved, and the second mixing threaded sleeve 13 is also provided with a corresponding groove 22, so that preliminary shearing can be performed before shearing, and the shearing dispersion effect is submitted.

[0060] Further, the number of the first kneading assemblies is one or more, and the number of the first pressurizing kneading assemblies is one or more; the more the number of the first kneading assemblies and the first pressurizing kneading assemblies, the better the shearing and dispersing effect on the plastic, and the production quality is effectively improved.

[0061] The working principle of the embodiment is as follows: first, the feeding device 3 puts the plastic raw material from the feeding port 2, the rotating motor 5 drives the first main shaft 7 and the second main shaft 8 to rotate, then the first upstream conveying threaded sleeve 10 and the second upstream conveying threaded sleeve 11 are meshed with the same rotation to extrude and convey the plastic, the first mixing threaded sleeve 12 and the second mixing threaded sleeve 13 are further meshed with the same rotation to extrude and shear the plastic, the meshing teeth on the first meshing sleeve body and the second meshing sleeve body 16 are meshed with each other to shear and disperse the plastic, continue to forward convey, the pressurizing meshing teeth 18 on the first pressurizing meshing sleeve body and the second pressurizing meshing sleeve body 19 are meshed with each other to shear and disperse the plastic, while the conveying speed is slowed down, finally the first downstream conveying threaded sleeve 20 and the second downstream conveying threaded sleeve 21 cooperate with each other to convey the plastic out; at the air extraction window 23, the horizontal linear cylinder 25 piston rod extends, drives the driving block 31 to cooperate with the vertical strip-shaped hole 33 of the guide rod 29, the cleaning block 27 rises, then the piston rod quickly retracts, the compression spring 30 releases the pressure, drives the cleaning block 27 to quickly descend, falls into the air extraction window 23, then the piston rod extends again to drive the cleaning block 27 to rise, and the air extraction starts through the air extraction joint 26.

[0062] The above-described embodiment is only a description of the preferred embodiment of the present application, and is not intended to limit the scope of the present application. Various modifications and improvements of the technical solutions of the present application made without departing from the design spirit of the present application shall fall within the protection scope determined by the claims of the present application.

Claims

1. A twin-screw extruder, comprising a base, a barrel fixed on the base, a first screw and a second screw rotatably mounted inside the barrel, a rotary power device fixed on the base for driving the first and second screws to rotate in the same direction, a feed inlet at the upstream end of the barrel, a feeding device at the feed inlet, and an extrusion die fixed at the lower end of the barrel, characterized in that: The first screw unit and the second screw unit have the same structure. The first screw unit includes a first main shaft. The first main shaft is splined with a first upstream conveying component, a first mixing component, a first kneading component, a first pressurized kneading component and a first downstream conveying component in the conveying direction. The corresponding second main shaft is splined with a second upstream conveying component, a second mixing component, a second kneading component, a second pressurized kneading component and a second downstream conveying component in the conveying direction. The first upstream conveying component and the second upstream conveying component have the same structure. The first upstream conveying component includes a first upstream conveying threaded sleeve, and the second upstream conveying component includes a second upstream conveying threaded sleeve. The first upstream conveying threaded sleeve and the second upstream conveying threaded sleeve mesh with each other. The first mixing component includes a first mixing threaded sleeve, and the second mixing component includes a second mixing threaded sleeve. The first mixing threaded sleeve and the second mixing threaded sleeve mesh with each other, and the pitch of the second mixing threaded sleeve is less than the pitch of the first upstream conveying threaded sleeve. The first kneading assembly includes a first kneading sleeve, which is splined onto a first main shaft. The first kneading sleeve has a plurality of kneading teeth that are staggered at 90° and spaced apart. The tooth surfaces of the kneading teeth are perpendicular to the axis of the first kneading sleeve. The diameter of the contour circle at the outer end of each kneading tooth gradually decreases along the conveying direction. The structure of the second kneading assembly is the same as that of the first kneading assembly, and the kneading teeth on the second kneading assembly mesh with the kneading teeth on the first kneading assembly. The first pressure kneading assembly includes a first pressure kneading sleeve, which is splined onto a first main shaft. The first pressure kneading sleeve has several spaced pressure kneading teeth with an interlacing angle of less than 90°. The diameter of the outline circle at the outer end of each pressure kneading tooth gradually decreases along the conveying direction. The tooth surface of each pressure kneading tooth is perpendicular to the axis of the first kneading sleeve. The second pressure kneading assembly has the same structure as the first pressure kneading assembly, and the pressure kneading teeth on the second pressure kneading assembly mesh with the pressure kneading teeth on the first pressure kneading assembly. The structure of the first downstream conveying assembly is the same as that of the first upstream conveying assembly, and the structure of the second downstream conveying assembly is the same as that of the second upstream conveying assembly; The material cylinder is also provided with an air extraction window, and an air extraction box is fixed on the material cylinder at the air extraction window. The air extraction box is provided with an air extraction connector that communicates with the negative pressure air extraction device. The air extraction box is provided with a cleaning device for cleaning the plastic adhering to the air extraction window.

2. The twin-screw extruder as described in claim 1, characterized in that: The cleaning device includes a cleaning block that is vertically and vertically installed inside the suction box. The cleaning block is coated with polytetrafluoroethylene. The shape of the cleaning block is adapted to the shape of the suction window. The cleaning block is driven by a vertical lifting power device to be inserted into the suction window from top to bottom. When the cleaning block is at the top position, it is disengaged from the suction window.

3. A twin-screw extruder as described in claim 2, characterized in that: An installation plate is fixed on the air extraction box. At least two guide rods are fixed on the upper end of the cleaning block. The cleaning block is vertically slidably installed on the installation plate through the guide rods. A compression spring is fitted on the guide rod and is located between the cleaning block and the installation plate. The vertical lifting power device is fixed on the installation plate.

4. A twin-screw extruder as described in claim 3, characterized in that: The vertical lifting power device includes a linear power device fixed to the mounting plate and arranged horizontally. A drive block is fixed on the power end of the linear power device. An inclined drive slope is provided at the upper end of the drive block. A vertical strip hole that cooperates with the drive slope of the drive block is provided on one of the guide rods. A limiting structure that restricts the lowering limit position of the cleaning block is provided on the other guide rod.

5. A twin-screw extruder as described in claim 3, characterized in that: The vertical lifting power device includes a swing fulcrum fixed to the mounting plate. A drive lever is oscillatingly mounted on the swing fulcrum, which divides the drive lever into a short arm and a long arm. A horizontal strip hole is provided at the upper end of one of the guide rods. A movable pin is hinged to the long arm and inserted into the horizontal strip hole. A vertical drive cylinder is also fixed on the mounting plate. The piston rod of the vertical drive cylinder is arranged downward and abuts against the short arm.

6. A twin-screw extruder as described in claim 4 or 5, characterized in that: The interlacing angle of the pressurized meshing teeth is 60°.

7. A twin-screw extruder as described in claim 6, characterized in that: In the first kneading component, at least one of the kneading teeth has a spacing that is not equal to the other spacings.

8. A twin-screw extruder as described in claim 7, characterized in that: The first hybrid threaded sleeve has radially extending grooves on its threads.

9. A twin-screw extruder as described in claim 8, characterized in that: The number of the first kneading components is one or more, and the number of the first pressure kneading components is one or more.

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