Twin-screw extrusion apparatus and method of processing thereof

Abstract

The application discloses a double-screw extrusion device and a processing method thereof, wherein the double-screw extrusion device comprises a barrel and a double-screw mechanism; the double-screw mechanism comprises a first screw, a second screw and a driving assembly; the driving assembly comprises a plurality of idlers and two mutually meshing elliptic gears; one of the elliptic gears is fixedly connected with the first screw, the other elliptic gear rotates synchronously with one idler, and the last idler is fixedly connected with the second screw; the rotating speed of the first screw is omega1=N, the eccentricity of the elliptic gear is k, and 0 < k < 0.8; the included angle between the first screw and the second screw and the long axis of the elliptic gear is alpha; and the rotating speed of the second screw is omega2, which satisfies: the melting, mixing and exhaust efficiency can be strengthened, and the melting plasticizing and mixing effect of the material can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of twin-screw extruders, and particularly to a twin-screw extrusion device and its processing method. Background Art

[0002] Twin-screw extruders are common plastic processing equipment, mainly used for mixing materials. Existing twin-screw extruders mainly drive the rotation of the twin screws through cylindrical gears, but this method has poor effects on the melting, plasticizing and mixing of materials and cannot meet production requirements. Summary of the Invention

[0003] The present invention aims to at least solve one of the technical problems in the related art. For this purpose, the present invention provides a twin-screw extrusion device that can achieve the effects of melting, plasticizing and mixing materials and improve production quality.

[0004] The present invention also proposes a processing method for the above twin-screw extrusion device.

[0005] According to the first aspect of the embodiments of the present invention, a twin-screw extrusion device is provided, including a barrel and a twin-screw mechanism; the twin-screw mechanism includes a first screw, a second screw and a driving component. The first screw and the second screw are both rotatably connected to the barrel, the first screw meshes with the second screw, the driving component includes a plurality of idler gears and two meshing elliptical gears. One of the elliptical gears is fixedly connected to the first screw, and the other elliptical gear rotates synchronously with one of the idler gears. The plurality of idler gears are connected in transmission, and the last idler gear is fixedly connected to the second screw, so that the first screw and the second screw rotate in the same direction; wherein, the first screw rotates at a constant speed, the rotational speed of the first screw is ω1 = N, the eccentricity of the elliptical gear is k, and 0 < k < 0.8. The included angle between the center line connecting the first screw and the second screw and the major axis of the elliptical gear is The rotational speed of the second screw is ω2, satisfying:

[0006] The twin-screw extrusion device of the embodiments of the present invention has at least the following beneficial effects: The first screw and the second screw are both rotatably connected to the barrel, and the first screw meshes with the second screw. One of the elliptical gears is fixedly connected to the first screw, and the other elliptical gear rotates synchronously with one of the idler gears. The plurality of idler gears are connected in transmission, and the last idler gear is fixedly connected to the second screw. Driving the elliptical gear connected to the first screw to rotate, so that the first screw rotates at a constant speed, and the rotational speed of the second screw changes periodically with time. By setting the rotational speed of the first screw as ω1 = N, the eccentricity of the elliptical gear as k, and 0 ≤ k < 0.8, and the included angle between the center line connecting the first screw and the second screw and the major axis of the elliptical gear is and Make the rotational speed ω2 of the second screw satisfy... This allows for the periodic compression and expansion of the screw channel volume between the first and second screws, periodic transient disturbances in the velocity field, and the reorientation and stretching effect at the interface of the processed material. This enhances the efficiency of melting, mixing, and venting, improves the melting, plasticizing, and mixing effects of the material, and ultimately improves production quality.

[0007] According to some embodiments of the present invention, the outer diameter of the first screw and the second screw is D, the outer radius of the first screw and the second screw is R, the inner diameter of the first screw and the second screw is d, and the inner radius of the first screw and the second screw is r;

[0008] The center distance between the first screw and the second screw is C, and

[0009] The meshing angle between the first screw and the second screw is β, and

[0010] The cross-section of the first screw is composed of curved arc S 12 S 23 S 34 S 45 S 56 S 67 S 78 S 89 S 91 Connecting them sequentially, the corresponding central angles and The cross-section of the second screw is formed by the curved arc S′ 12 S′ 23 S′ 34 S′ 45 S′ 56 S′ 67 S′ 78 S′ 89 S′ 91 Connect them sequentially to form the corresponding central angles. and The rotation center of the first screw is O, and the rotation center of the second screw is O′;

[0011] Among them, S 12 S 56 S 91 S is the circular arc of the root circle with center O and radius r; 34 S 78 S′ is the top circle arc with center O and radius R; 12 S′ 56 S′ 91Let S′ be the arc of the top circle with center O′ and radius R. 34 S′ 78 Let be the circular arc of the root circle with center O′ and radius r;

[0012] The initial phase angle is θ0, and 0 ≤ θ0 ≤ 360°, K d = (1+k) / (1-k);

[0013] satisfy:

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029] According to some embodiments of the present invention, the connection points of two adjacent curved arcs of the first screw are M1, M2, M3, M4, M5, M6, M7, M8 and M9, respectively corresponding to curved arc S. 12 S 23 S 34 S 45 S 56 S 67 S 78 S 89 and S 91 Given an auxiliary angle θ, 0 ≤ θ ≤ β;

[0030] With OM2 as the polar axis, the arc S of the curve 23 The polar radius corresponding to any position is OP2 = ρ2(θ), and the angle between the polar radius OP2 and the polar axis OM2 is the polar angle ε2(θ), satisfying:

[0031]

[0032]

[0033] With OM5 as the polar axis, the curve arc S 45 The polar radius corresponding to any position is OP5 = ρ4(θ), and the angle between the polar radius OP5 and the polar axis OM5 is the polar angle ε4(θ), satisfying:

[0034]

[0035]

[0036] With OM6 as the polar axis, the curve arc S 67 The polar radius corresponding to any position is OP6 = ρ6(θ), and the angle between the polar radius OP6 and the polar axis OM6 is the polar angle ε6(θ), satisfying:

[0037]

[0038]

[0039] With OM9 as the polar axis, the curve arc S 89 The polar radius corresponding to any position is OP8 = ρ8(θ), and the angle between the polar radius OM8 and the polar axis OM9 is the polar angle ε8(θ), satisfying:

[0040]

[0041]

[0042] According to some embodiments of the present invention, the connection points of two adjacent curved arc segments of the second screw are N1, N2, N3, N4, N5, N6, N7, N8 and N9, respectively corresponding to curved arc S′. 12 S′ 23 S′ 34 S′ 45 S′ 56 S′ 67 S′ 78 S′ 89 and S′ 91 Given an auxiliary angle θ, 0 ≤ θ ≤ β;

[0043] With O′N3 as the polar axis, the curve arc S′23 The polar radius corresponding to any position is OP. 2′ =ρ 2′ (θ), polar radius OP 2′ The angle between the polar axis ON3 and the polar angle is ε. 2′ (θ), satisfying:

[0044]

[0045]

[0046] With O′N4 as the polar axis, the curve arc S′ 45 The polar radius corresponding to any position is OP. 4′ =ρ 4′ (θ), polar radius OP 5′ The angle between the polar axis ON4 and the polar angle is ε. 4′ (θ), satisfying:

[0047]

[0048]

[0049] With O′N6 as the polar axis, the curve arc S′ 67 The polar radius corresponding to any position is OP. 6′ =ρ 6′ (θ), polar radius OP 6′ The angle between the polar axis ON6 and the polar angle is ε. 6′ (θ), satisfying:

[0050]

[0051]

[0052] With O′N8 as the polar axis, the curve arc S′ 89 The polar radius corresponding to any position is OP. 8′ =ρ 8′ (θ), polar radius OP 8′ The angle between the polar axis ON7 and the polar angle is ε. 8′ (θ), satisfying:

[0053]

[0054]

[0055] According to some embodiments of the present invention, along the axial direction of the first screw, the barrel is sequentially provided with a conveying section, a melting section, a venting section and a mixing and extrusion section, the conveying section having a feed inlet, the venting section having a venting outlet, and the mixing and extrusion section having a discharge outlet.

[0056] According to some embodiments of the present invention, the outer diameters of both the first screw and the second screw are tangent to the inner wall of the barrel.

[0057] According to a second aspect of the present invention, a method for processing a twin-screw extruder is provided, including the twin-screw extruder of the first aspect of the present invention, the method comprising:

[0058] Step S100: Add materials;

[0059] Step S200: The first screw and the second screw rotate in the same direction. The first screw rotates at a constant speed, and the rotational speed of the second screw changes periodically with time. The first screw and the second screw cooperate to convey the material.

[0060] Step S300: The material is melted by external heating and the heat generated by the rotation of the first screw and the second screw, so that the material forms a melt;

[0061] Step S400: The barrel, the first screw and the second screw cooperate to extrude and stretch the material, and drive the material to be extruded from the discharge port to form a shape.

[0062] The processing method of the twin-screw extrusion device of the present invention has at least the following beneficial effects: by setting up the twin-screw extrusion device of the first aspect of the present invention, by introducing the compression and expansion generated by the flow channel, the extrusion and stretching action of re-compression and re-expansion, the periodic transient disturbance of the velocity field, and the stretching and reorientation action of the material mixing and dispersion process, the melt mixing effect and the volatilization efficiency are enhanced, and the periodic pulsation effect is superimposed to achieve a more effective self-cleaning effect.

[0063] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0064] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0065] Figure 1 This is a schematic diagram of a twin-screw extrusion apparatus according to a first aspect embodiment of the present invention;

[0066] Figure 2 This is a schematic diagram of the meshing of the first screw and the second screw of the twin-screw extrusion apparatus according to a first aspect embodiment of the present invention;

[0067] Figure 3This is a schematic cross-sectional view of the engagement of the first screw and the second screw in the first aspect embodiment of the present invention, where θ0 = 0° and k = 0.2.

[0068] Figure 4 This is a schematic cross-sectional view of the first screw with θ0 = 0° and k = 0.2 according to the first aspect of the present invention;

[0069] Figure 5 This is a cross-sectional schematic diagram of the second screw with θ0 = 0° and k = 0.2 according to the first aspect embodiment of the present invention;

[0070] Figure 6 This is a schematic cross-sectional view of the engagement of the first screw and the second screw, θ0 = 63° and k = 0.2, according to the first aspect of the present invention.

[0071] Figure 7 This is a schematic cross-sectional view of the engagement of the first screw and the second screw, θ0 = 0° and k = 0.5, according to the first aspect of the present invention.

[0072] Figure 8 This is a schematic diagram of the eccentricity of the elliptical gear and the instantaneous transmission ratio of the first screw and the second screw in a twin-screw extrusion apparatus according to a first aspect embodiment of the present invention.

[0073] Figure 9 This is a schematic diagram of the central angles of the top and root circles of the first screw cross-section with different phase angles θ0 when k = 0.2, according to the first aspect of the present invention.

[0074] Figure 10 The first screw cross-sectional curve arc S of the embodiment of the first aspect of the present invention with different phase angles θ0 when k = 0.2 is described. 23 S 45 S 67 S 89 A diagram showing the corresponding central angle;

[0075] Figure 11 The second screw cross-sectional curve arc S′ of the embodiment of the first aspect of the present invention with different phase angles θ0 when k = 0.2 23 S′ 45 S′ 67 S′ 89 A diagram showing the corresponding central angle;

[0076] Figure 12 This is a schematic diagram of a processing method for a twin-screw extrusion apparatus according to a second aspect embodiment of the present invention.

[0077] Explanation of reference numerals in the attached figures:

[0078] Barrel 100, conveying section 110, feed inlet 111, melting section 120, venting section 130, venting outlet 131, mixing and extrusion section 140, discharge outlet 141;

[0079] Twin-screw mechanism 200, first screw 210, second screw 220;

[0080] Flow channel 300. Detailed Implementation

[0081] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0082] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0083] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0084] In the description of this invention, unless otherwise explicitly defined, terms such as "setting," "installing," and "connecting" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0085] Understandably, referring to Figures 1 to 5 ,as well as Figure 8, the twin-screw extrusion device according to the embodiment of the first aspect of the present invention includes a barrel 100 and a twin-screw mechanism 200; the twin-screw mechanism 200 includes a first screw 210, a second screw 220 and a driving component. Both the first screw 210 and the second screw 220 are rotatably connected to the barrel 100, and the first screw 210 meshes with the second screw 220. The driving component includes a plurality of idler wheels and two meshing elliptical gears. One of the elliptical gears is fixedly connected to the first screw 210, and the other elliptical gear rotates synchronously with an idler wheel. The plurality of idler wheels are connected in transmission, and the last idler wheel is fixedly connected to the second screw 220, so that the first screw 210 and the second screw 220 rotate in the same direction; wherein, the first screw 210 rotates at a constant speed, the rotation speed of the first screw 210 is ω1 = N, the eccentricity of the elliptical gear is k, and 0 < k < 0.8. The included angle between the center line connecting the first screw 210 and the second screw 220 and the major axis of the elliptical gear is The rotation speed of the second screw 220 is ω2, and it satisfies:

[0086] Both the first screw 210 and the second screw 220 are rotatably connected to the barrel 100, and the first screw 210 meshes with the second screw 220. One of the elliptical gears is fixedly connected to the first screw 210, and the other elliptical gear rotates synchronously with an idler wheel. The plurality of idler wheels are connected in transmission, and the last idler wheel is fixedly connected to the second screw 220. Driving the elliptical gear connected to the first screw 210 to rotate to drive the idler wheel to rotate, so that the other elliptical gear can be driven to rotate, enabling the first screw 210 to rotate at a constant speed, and the rotation speed of the second screw 220 changes periodically with time. By setting the rotation speed of the first screw 210 as ω1 = N, the eccentricity of the elliptical gear as k, and 0 < k < 0.8, and the included angle between the center line connecting the first screw 210 and the second screw 220 and the major axis of the elliptical gear is And Make the rotation speed ω2 of the second screw 220 satisfy So that the screw groove volume between the first screw 210 and the second screw 220 is periodically compressed and expanded, the velocity field is periodically transiently disturbed, and the reorientation and stretching effect of the processed material interface are achieved, strengthening the melting, mixing and exhaust efficiency, accelerating the melting process of the material, improving the melting and plasticizing and mixing effect of the material, and improving the production quality.

[0087] It should be noted that the transmission ratio of the first screw 210 and the second screw 220 is That is, the rotation speed of the second screw 220 changes with the rotation angle of the first screw 210, so that the shear force and friction force received by the material between the first screw 210 and the second screw 220 change periodically, improving the dispersion and mixing ability of the material and improving the production quality.

[0088] The system comprises multiple idler gears connected by a transmission mechanism. Adjacent idler gears can mesh or rotate coaxially. The last idler gear is the last in the idler gear transmission chain, and its rotation direction is the same as that of the first screw 210. The two elliptical gears have the same number of teeth, allowing the rotational speed of the second screw 220 to change periodically with time, thus improving the mixing efficiency of the material. Furthermore, the elliptical gears can be driven by an electric motor, pneumatic motor, or hydraulic motor, which will not be elaborated upon here.

[0089] Furthermore, refer to Figure 8 The larger the eccentricity k of the elliptical gear, the larger the amplitude of the transmission ratio of the first screw 210 and the second screw 220. That is, the eccentricity k of the elliptical gear is directly proportional to the amplitude of the transmission ratio of the first screw 210 and the second screw 220.

[0090] Specifically, refer to Figures 3 to 11 The outer diameter of the first screw 210 and the second screw 220 is D, the outer radius of the first screw 210 and the second screw 220 is R, the inner diameter of the first screw 210 and the second screw 220 is d, and the inner radius of the first screw 210 and the second screw 220 is r.

[0091] The center distance between the first screw 210 and the second screw 220 is C, and

[0092] The meshing angle between the first screw 210 and the second screw 220 is β, and

[0093] The cross-section of the first screw 210 is formed by the curved arc S 12 S 23 S 34 S 45 S 56 S 67 S 78 S 89 S 91 Connecting them sequentially, the corresponding central angles and The cross-section of the second screw 220 is formed by the curved arc S′ 12 S′ 23 S′ 34 S′ 45 S′ 56 S′ 67 S′ 78 S′ 89 S′ 91 Connect them sequentially to form the corresponding central angles. and The rotation center of the first screw 210 is O, and the rotation center of the second screw 220 is O′;

[0094] Among them, S 12 S 56 S 91 S is the circular arc of the root circle with center O and radius r; 34 S 78 S′ is the top circle arc with center O and radius R; 12 S′ 56 S′ 91 Let S′ be the arc of the top circle with center O′ and radius R. 34 S′ 78 Let be the circular arc of the root circle with center O′ and radius r;

[0095] The initial phase angle is θ0, and 0 ≤ θ0 ≤ 360°, K d = (1+k) / (1-k);

[0096] satisfy:

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107]

[0108]

[0109]

[0110]

[0111]

[0112] By defining the structure of the curved arcs of each segment of the first screw 210 and the second screw 220, the first screw 210 and the second screw 220 are kept meshed while rotating in the same direction, and the speed ratio of the first screw 210 and the second screw 220 changes periodically with time, so that the first screw 210 and the second screw 220 can achieve a self-cleaning effect. This allows the material to form a continuous material flow in the barrel, reducing material retention and blockage, reducing material adhesion between the screw and the barrel, reducing the risk of blockage and scaling, and making the material residence time distribution relatively uniform, which is beneficial to improving product quality and stability.

[0113] When the central angle corresponding to the 220 arc segment of the second screw is given, that is, given When the values ​​are appropriate, the system of equations described above can be solved to obtain the values ​​of the central angles corresponding to the remaining curved arcs of the first screw 210 and the second screw 220, i.e. as well as and Both can be calculated. For example, when D / d = 1.4, the central angles of the top and root circles of the second screw 220 are selected as follows: When θ0=0°, the central angles of the first screw 210 corresponding to different eccentricities k are shown in Table 1 below:

[0114] Table 1. Central angles of the arcs of the first screw 210 curves corresponding to different eccentricities k.

[0115]

[0116] Similarly, when θ0=0°, the central angles of the second screw 220° corresponding to different eccentricities k are shown in Table 2 below:

[0117] Table 2 shows the central angles of the arcs of the second screw 220 curves corresponding to different eccentricities k.

[0118]

[0119] Specifically, refer to Figures 3 to 11 The connection points of two adjacent curved arcs of the first screw 210 are M1, M2, M3, M4, M5, M6, M7, M8 and M9, which correspond to the curved arcs S respectively. 12 S 23 S 34 S 45 S 56 S 67 S 78 S 89 and S 91 Given an auxiliary angle θ, 0 ≤ θ ≤ β;

[0120] With OM2 as the polar axis, the arc S of the curve 23The polar radius corresponding to any position is OP2 = ρ2(θ), and the angle between the polar radius OP2 and the polar axis OM2 is the polar angle ε2(θ), satisfying:

[0121]

[0122]

[0123] With OM5 as the polar axis, the curve arc S 45 The polar radius corresponding to any position is OP5 = ρ4(θ), and the angle between the polar radius OP5 and the polar axis OM5 is the polar angle ε4(θ), satisfying:

[0124]

[0125]

[0126] With OM6 as the polar axis, the curve arc S 67 The polar radius corresponding to any position is OP6 = ρ6(θ), and the angle between the polar radius OP6 and the polar axis OM6 is the polar angle ε6(θ), satisfying:

[0127]

[0128]

[0129] With OM9 as the polar axis, the curve arc S 89 The polar radius corresponding to any position is OP8 = ρ8(θ), and the angle between the polar radius OP8 and the polar axis OM9 is the polar angle ε8(θ), satisfying:

[0130]

[0131]

[0132] By defining S of the first screw 210 23 S 45 S 67 and S 89 The four non-circular curve arc equations are used to ensure that the first screw 210 can maintain engagement with the second screw 220 during rotation, thereby improving the self-cleaning effect of the first screw 210 and the second screw 220, and improving the dispersion and mixing effect of materials, thus improving production quality.

[0133] It should be noted that the curve arc S 12 The two endpoints are M1 and M2, and the curve arc S 34 The two endpoints are M3 and M4, and so on. Curve arc S 91 With curve arc S 12 The connection point between them is M1, and the curve arc S12 With curve arc S 23 The connection point between them is M2, and so on.

[0134] Specifically, refer to Figures 3 to 11 The connection points of two adjacent curved arcs of the second screw 220 are N1, N2, N3, N4, N5, N6, N7, N8 and N9, which correspond to the curved arc S′ respectively. 12 S′ 23 S′ 34 S′ 45 S′ 56 S′ 67 S′ 78 S′ 89 and S′ 91 Given an auxiliary angle θ, 0 ≤ θ ≤ β;

[0135] With O′N3 as the polar axis, the curve arc S′ 23 The polar radius corresponding to any position is OP. 2′ =ρ 2′ (θ), polar radius OP 2′ The angle between the polar axis ON3 and the polar angle is ε. 2′ (θ), satisfying:

[0136]

[0137]

[0138] With O′N4 as the polar axis, the curve arc S′ 45 The polar radius corresponding to any position is OP. 4′ =ρ 4′ (θ), polar radius OP 4′ The angle between the polar axis ON4 and the polar angle is ε. 4′ (θ), satisfying:

[0139]

[0140]

[0141] With O′N6 as the polar axis, the curve arc S′ 67 The polar radius corresponding to any position is OP. 6′ =ρ 6′ (θ), polar radius OP 6′ The angle between the polar axis ON6 and the polar angle is ε. 6′ (θ), satisfying:

[0142]

[0143]

[0144] With O′N8 as the polar axis, the curve arc S′ 89 The polar radius corresponding to any position is OP. 8′ =ρ 8′ (θ), polar radius OP 8′ The angle between the polar axis ON7 and the polar angle is ε. 8′ (θ), satisfying:

[0145]

[0146]

[0147] By defining S′ of the second screw 220 23 S′ 45 S′ 67 and S′ 89 The four non-circular curve arc equations are used to ensure that the second screw 220 can maintain engagement with the first screw 210 during rotation, thereby improving the self-cleaning effect of the first screw 210 and the second screw 220, and improving the dispersion and mixing effect of materials, thus improving production quality.

[0148] Understandably, referring to Figure 1 Along the axial direction of the first screw 210, the barrel 100 is sequentially provided with a conveying section 110, a melting section 120, a venting section 130, and a mixing and extrusion section 140. The conveying section 110 has a feed inlet 111, the venting section 130 has a vent 131, and the mixing and extrusion section 140 has a discharge outlet 141. Material is fed in through the feed inlet 111 so that it can enter the conveying section 110. Then, the first screw 210 and the second screw 220 drive the material to be conveyed so that it can enter the melting section 120 to melt and mix the material together. Then, the material enters the venting section 130 so that the exhaust gas can be discharged from the vent 131, and the material enters the mixing and extrusion section 140 so that it can be discharged from the discharge outlet 141, thereby enhancing the efficiency of melting, mixing, and venting.

[0149] Understandably, referring to Figure 1 The outer diameters of both the first screw 210 and the second screw 220 are tangent to the inner wall of the barrel 100. By setting the first screw 210 and the second screw 220 to be tangent to the inner wall of the barrel 100, the extrusion and stretching of the material in the flow channel 300 can be increased, resulting in greater disturbance and mixing, and improving the extrusion efficiency of the material.

[0150] Understandably, referring to Figure 1 and Figure 12 The processing method of the twin-screw extruder according to a second aspect embodiment of the present invention includes the twin-screw extruder according to a first aspect embodiment of the present invention, and the processing method includes:

[0151] Step S100: Add materials;

[0152] Step S200: The first screw 210 and the second screw 220 rotate in the same direction. The first screw 210 rotates at a constant speed, and the speed of the second screw 220 changes periodically with time. The first screw 210 and the second screw 220 cooperate to convey materials.

[0153] Step S300: The material is melted by external heating and the heat generated by the rotation of the first screw 210 and the second screw 220, so that the material forms a melt;

[0154] Step S400: The barrel 100, the first screw 210 and the second screw 220 work together to extrude and stretch the material, and drive the material to be extruded from the discharge port 141 to form a shape.

[0155] Material is fed into the barrel 100, driving the first screw 210 and the second screw 220 to rotate in the same direction. The first screw 210 rotates at a constant speed, while the rotational speed of the second screw 220 changes periodically with time, causing the transmission ratio of the first screw 210 and the second screw 220 to change periodically with time. This results in a periodic change in the volume within the flow channel 300, which in turn drives the material conveying. The material is melted by the heat generated by the external heating element and the rotational friction between the first screw 210 and the second screw 220, forming a melt. This melt allows the material to be compressed and stretched within the flow channel 300, improving the dispersion and mixing effect. Then, the barrel 100, the first screw 210, and the second screw 220 work together to drive the material to be extruded from the discharge port 141. By introducing the compression and expansion, recompression and reexpansion, extrusion and stretching effects generated by the flow channel 300, the periodic transient disturbance of the velocity field, and the stretching and reorientation effect of the material mixing and dispersion process, the melting and mixing effect and the volatilization efficiency are enhanced. It can also ensure that the first screw 210 and the second screw 220 can still mesh and rotate with each other under the premise of variable speed ratio. The superimposed periodic pulsation effect can more effectively achieve the self-cleaning effect.

[0156] It should be noted that the external heating element can be a heating mechanism such as an electric heating wire or an electric heating coil, which can be used to heat the material so that it melts.

[0157] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A twin-screw extruder, characterized in that, include: barrel; A twin-screw mechanism includes a first screw, a second screw, and a drive assembly. Both the first screw and the second screw are rotatably connected to the barrel. The first screw meshes with the second screw. The drive assembly includes multiple idler gears and two meshing elliptical gears. One of the elliptical gears is fixedly connected to the first screw, and the other elliptical gear rotates synchronously with one of the idler gears. The multiple idler gears are connected by a transmission, and the last idler gear is fixedly connected to the second screw, so that the first screw and the second screw rotate in the same direction. The first screw rotates at a constant speed, and the rotational speed of the first screw is... The eccentricity of the elliptical gear is ,and The angle between the line connecting the centers of the first screw and the second screw and the major axis of the elliptical gear is φ, and the rotational speed of the second screw is... ,satisfy: ; The outer diameter of the first screw and the second screw is D, the outer radius of the first screw and the second screw is R, the inner diameter of the first screw and the second screw is d, and the inner radius of the first screw and the second screw is r; The center distance between the first screw and the second screw is C, and C = R + r = ; The meshing angle between the first screw and the second screw is ,and ; The cross-section of the first screw is composed of a curved arc. , , , , , , , , Connect them sequentially to form the corresponding central angles. , , , , , , , and The cross-section of the second screw is composed of a curved arc. , , , , , , , , Connect them sequentially to form the corresponding central angles. , , , , , , , and The rotation center of the first screw is The rotation center of the second screw is ; in, , , Let O be the circular arc of the root circle with center O and radius r; , The top circle arc is centered at O ​​and has a radius of R. , , , for The top circle arc is centered at a point with radius R. , For the sake of An arc of the root circle with center and radius r; The initial phase angle is ,and , ; satisfy: ； ； ； ； ； ； ； ； ； ； ； ； ； ； 。 2. The twin-screw extruder according to claim 1, characterized in that, The connection point of two adjacent curved arcs of the first screw is , , , , , , , and , respectively corresponding to the curve arc , , , , , , , and Given an auxiliary angle θ, ; by If the polar axis is used, then the curve arc The polar radius corresponding to any position is = Polar diameter With polar axis The included angle is the polar angle is ,satisfy: ； ； by If the polar axis is used, then the curve arc The polar radius corresponding to any position is = Polar diameter With polar axis The included angle is the polar angle is ,satisfy: ； ； by If the polar axis is used, then the curve arc The polar radius corresponding to any position is = Polar diameter With polar axis The included angle is the polar angle is ,satisfy: ； ； by If the polar axis is used, then the curve arc The polar radius corresponding to any position is = Polar diameter With polar axis The included angle is the polar angle is ,satisfy: ； 。 3. The twin-screw extruder according to claim 1, characterized in that, The connection point of the two adjacent curved arcs of the second screw is , , , , , , , and , respectively corresponding to the curve arc , , , , , , , and Given an auxiliary angle θ, ; by If the polar axis is used, then the curve arc The polar radius corresponding to any position is = Polar diameter With polar axis The included angle is the polar angle is ,satisfy: ； ； by If the polar axis is used, then the curve arc The polar radius corresponding to any position is = Polar diameter With polar axis The included angle is the polar angle is ,satisfy: ； ； by If the polar axis is used, then the curve arc The polar radius corresponding to any position is = Polar diameter With polar axis The included angle is the polar angle is ,satisfy: ； ； by If the polar axis is used, then the curve arc The polar radius corresponding to any position is = Polar diameter With polar axis The included angle is the polar angle is ,satisfy: ； 。 4. The twin-screw extruder according to claim 1, characterized in that, Along the axial direction of the first screw, the barrel is sequentially provided with a conveying section, a melting section, a venting section and a mixing and extrusion section. The conveying section has a feed inlet, the venting section has a vent, and the mixing and extrusion section has a discharge outlet.

5. The twin-screw extruder according to claim 1, characterized in that, The outer diameters of both the first screw and the second screw are tangent to the inner wall of the barrel.

6. A processing method for a twin-screw extruder, characterized in that, The processing method includes a twin-screw extruder as described in any one of claims 1 to 5, comprising: Step S100: Add materials; Step S200: The first screw and the second screw rotate in the same direction. The first screw rotates at a constant speed, and the rotational speed of the second screw changes periodically with time. The first screw and the second screw cooperate to convey the material. Step S300: The material is melted by external heating and the heat generated by the rotation of the first screw and the second screw, so that the material forms a melt; Step S400: The barrel, the first screw and the second screw cooperate to extrude and stretch the material, and drive the material to be extruded from the discharge port to form a shape.

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