Extruder and extrusion processing method

Abstract

The embodiment of the application provides an extruder and an extrusion processing method, and belongs to the technical field of extruder equipment. The extruder comprises a cylinder and a screw assembly, the screw assembly comprises a first screw and a plurality of second screws, the first screw and the plurality of second screws rotate in the same direction and are arranged in the cylinder, the first screw and the second screw are engaged, and an engagement point is located on a plane formed by rotation axes of the first screw and the second screw; a top diameter of the first screw and a root diameter of the second screw are engaged at the plane; a root diameter of the first screw and a top diameter of the second screw are engaged at the plane; by keeping the engagement point of the first screw and the second screw in the plane formed by the two rotation axes, the maximum speed difference can be generated at the engagement point, so that the engagement performance is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of extruder equipment, in particular to an extruder and an extrusion processing method. BACKGROUND

[0002] The extruder is widely used in the fields of high polymer materials, food, medicine, and chemical industry, and undertakes the tasks of melting, mixing, and extrusion processing of materials. In order to ensure that the materials experience similar processing history, control the residence time distribution, and prevent the materials from overheating degradation, the self-cleaning function between the two screws needs to be realized, and therefore the geometry of the two screws needs to meet the conjugate requirement. However, the traditional double screw realizes the geometry construction based on the relative motion principle, which can realize the mutual engagement between the double screws and trigger the self-cleaning of the screw through the engagement point. However, the speed difference between the two screws in the traditional double screw does not reach the maximum when engaging, that is, the engagement performance does not reach the ideal state, and the engagement performance will affect the self-cleaning effect of the screw and the melting efficiency and dispersion mixing effect. Therefore, the self-cleaning effect of the traditional extruder and the melting efficiency and dispersion mixing effect still need to be improved. SUMMARY

[0003] The main purpose of the embodiments of the present application is to provide an extruder and an extrusion processing method, which aims to improve the self-cleaning effect of the extruder and the melting efficiency and dispersion mixing effect.

[0004] The extruder according to the first aspect of the present application comprises:

[0005] A barrel;

[0006] A screw assembly, the screw assembly comprising a first screw and a plurality of second screws, the first screw and the plurality of second screws rotating in the same direction and being arranged in the barrel, the first screw and the second screw being engaged and the engagement point being located on a plane formed by the rotation axes of the first screw and the second screw; the top diameter of the first screw and the root diameter of the second screw being engaged at the plane; and the root diameter of the first screw and the top diameter of the second screw being engaged at the plane.

[0007] The extrusion processing method according to the second aspect of the present application is applied to the extruder of any one of the first aspect, and the method comprises:

[0008] Obtaining the speed ratio of the first screw and the second screw;

[0009] Controlling the first screw and the second screw to rotate in the same direction at the speed ratio to transmit the material entering from the barrel inlet to the outlet of the barrel and process the material in the transmission process;

[0010] In the transmission process, the melting section of the barrel is monitored in real time.

[0011] determining whether to adjust the heating power of the heating device arranged in the melting section according to the result of temperature monitoring.

[0012] The extruder and the extrusion processing method provided by the application can realize self-cleaning by controlling the first screw and the second screw to rotate in the same direction, and when the first screw and the second screw mesh, the two screws can wipe each other, thereby realizing self-cleaning. Since the meshing point of the first screw and the second screw is always located in the plane formed by the two rotation axes, the first screw and the second screw rotate in opposite directions at the meshing point. When the root diameter of the first screw meshes with the top diameter of the second screw or the top diameter of the first screw meshes with the root diameter of the second screw, the maximum speed difference can be generated to improve the meshing performance. At this time, the shear effect caused by the speed difference can be fully utilized for the extrusion barrel to provide more homocentric orbits to trigger the chaotic mixing reinforcement effect. Therefore, the self-cleaning effect of the extruder, the melting efficiency and the dispersion mixing effect of the multiphase system can be improved by improving the meshing performance. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a schematic view of a structure combination structure of a first screw and a second screw with a rotation ratio of 2:1 provided by the application (except for a barrel);

[0014] Figure 2 is a schematic view of a three-screw mechanism structure provided by the application (except for a barrel);

[0015] Figure 3 is a schematic view of the meshing point of the extruder shown in the application; Figure 1

[0016] Figure 4 is a schematic view of the cross section of the first screw when the extruder meshes; Figure 1

[0017] Figure 5 is a schematic view of the cross section of the second screw when the extruder meshes; Figure 1

[0018] Figure 6 is a schematic view of the extruder shown in the application; Figure 1

[0019] Figure 7 is a schematic view of the structure when the screw is provided with a kneading structure; Figure 1

[0020] Figure 8 ​​​​​is a cross-sectional composition schematic diagram of the first screw and the second screw of the extruder with a speed ratio of 1:1 when meshing, provided by the embodiment of the present application;

[0021] Figure 9 is a schematic diagram of the first screw and the second screw combination structure of the extruder with a speed ratio of 1:1 (the screw contains kneading structure), provided by the embodiment of the present application;

[0022] Figure 10 is a flow schematic diagram of the extrusion processing method, provided by the embodiment of the present application.

[0023] Reference signs:

[0024] Barrel 100, conveying section 110, feed port 111, melting section 120, exhaust section 130, exhaust port 131, mixing extrusion section 140, discharge port 141,

[0025] First screw 210, second screw 220, rotation axis 230, broken line 240, kneading structure 250,

[0026] Flow channel 300. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the present application more clear and understandable, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0028] In order to make the purpose, technical scheme and advantages of the present application more clear and understandable, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of the present application, and are not intended to limit the present application. The terms "first", "second", "third", "fourth" and the like (if any) in the specification and the above drawings of the present application are used to distinguish similar objects, and do not necessarily describe a specific order or sequence.

[0030] Moreover, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the disclosure. One skilled in the relevant art will recognize, however, that the

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0032] Extruders are widely used in the fields of polymer materials, food, medicine, chemical industry, etc., and undertake the tasks of melting, mixing and extruding of materials. In order to ensure that the materials experience similar processing history, control the residence time distribution, and prevent the degradation of the materials due to overheating, the self-cleaning function between the two screws needs to be realized, and therefore the geometry of the two screws needs to meet the conjugate requirement. However, the traditional double screw realizes the geometry modeling based on the relative motion principle, which can realize the mutual engagement between the two screws and trigger the self-cleaning of the screw through the engagement point. However, it is found through research that, from the perspective of the cross section of the screw, only the contact between the two screws is ensured at all times, and the engagement point cannot be kept on the line connecting the rotation centers of the two screws at all times. The speed difference between the traditional double screws during engagement does not reach the maximum, and the homoclinic orbit perturbation cannot be provided, which further leads to the fact that the engagement performance does not reach the ideal state. The self-cleaning effect of the traditional extruder and the melting efficiency and dispersion mixing effect still need to be improved. Based on this, the present application proposes an extruder and an extrusion processing method, which can improve the self-cleaning effect of the extruder and the melting efficiency and dispersion mixing effect.

[0033] It should be noted that, Figures 1 to 9 O represents the rotation center of the first screw 210, and O1 represents the rotation center of the second screw 220. Point Q is the engagement point of the first screw 210 and the second screw 220 when they are engaged, which is on the line connecting O and O1. The following cross sections refer to the cross sections of the engagement region.

[0034] Referring to Figures 1 to 9 As shown in the figure, the extruder according to the present application comprises:

[0035] a barrel 100;

[0036] The screw assembly comprises a first screw 210 and a plurality of second screws 220, the first screw 210 and the plurality of second screws 220 rotate in the same direction and are arranged in the barrel 100, the first screw 210 and the second screw 220 are engaged, and the engagement point is located in a plane formed by the rotation axes 230 of the first screw 210 and the second screw 220; the top diameter of the first screw 210 and the root diameter of the second screw 220 are engaged at the plane; and the root diameter of the first screw 210 and the top diameter of the second screw 220 are engaged at the plane.

[0037] Therefore, by controlling the first screw 210 and the second screw 220 to rotate in the same direction, when the first screw 210 and the second screw 220 are engaged, mutual wiping between the two screws is realized, thereby realizing the self-cleaning function; since the engagement point of the first screw 210 and the second screw 220 is always located in the plane formed by the two rotation axes 230, the first screw 210 and the second screw 220 rotate in opposite directions at the engagement point, and when the root diameter of the first screw 210 and the top diameter of the second screw 220 or the top diameter of the first screw 210 and the root diameter of the second screw 220 are engaged, the maximum speed difference can be generated to improve the engagement performance; at this time, for the extrusion barrel, the shear effect caused by the speed difference can be fully utilized to provide more homoclinic orbits to trigger the chaotic mixing enhancement effect; therefore, the self-cleaning effect of the extruder and the melting efficiency and the dispersion mixing effect of the multiphase system can be improved by improving the engagement performance.

[0038] It should be noted that a plurality of indicates at least one, and the second screw 220 can be one or multiple, and the present application does not limit this. In some embodiments, referring to FIG. 1, the second screw 220 is provided with two, and the two second screws 220 are arranged in rows on both sides of the first screw 210. Figure 2 In other embodiments, as shown in FIG. 2, the second screw 220 is provided with one. Figure 1

[0039] It should be noted that the top diameter represents the longest distance from the rotation center of the cross section passing through the rotation axis 230 to the corresponding edge contour, and the root diameter represents the corresponding shortest distance.

[0040] It should be noted that two straight lines can determine a unique plane, so the rotation axes 230 of the first screw 210 and the second screw 220 can uniquely determine a plane.

[0041] ​It should be noted that in some embodiments, only the top diameter of the first screw 210 meshes with the root diameter of the second screw 220, and the root diameter of the first screw 210 meshes with the top diameter of the second screw 220, and in other embodiments, the curved segments between the top diameter and the root diameter of the first screw 210 and the second screw 220 have multiple meshing points when passing through the plane formed by the rotation axis 230, at this time, an engagement curve will be formed on the plane, for example, when the first screw 210 and the second screw 220 always remain engaged at the plane, at this time, an engagement curve will be formed on the plane Figure 3 The broken line 240 shown by the continuous Z-shaped line segment is connected.

[0042] It should be noted that when rotating in the same direction, the polar diameter of the arc segment of the first screw 210 and the second screw 220 along the rotation direction is opposite, so that conjugation can be achieved, for example, for the first screw 210, the polar diameter of the arc segment corresponding to the plane at time t is increasing, and for the second screw 220, the polar diameter of the arc segment corresponding to the plane at the same time t is decreasing.

[0043] It should be noted that the meshing point is the point where the first screw 210 and the second screw 220 mesh with the plane formed by the rotation axis 230. At this time, the distance between the meshing point and the rotation center of the first screw 210 in the same cross section is in the range of the root diameter of the first screw 210 and the top diameter of the first screw 210. For example, assuming that the root diameter is r and the top diameter is R, the distance between the meshing point and the rotation center of the first screw 210 is in the range of [r, R]; when the first screw 210 and the second screw 220 always mesh at the plane, the distance between the meshing point and the rotation center of the first screw 210 gradually increases from r to R and gradually decreases from R to r; and the cycle is repeated.

[0044] It should be noted that in some embodiments, the barrel 100 is an "8" shaped structure formed by the intersection of cylindrical holes with parallel axes. The flow field formed by the screw assembly and the inner wall of the barrel 100 will produce a periodic wedge-shaped extrusion effect on the wall surface near the upper and lower sharp corners of the meshing point with the periodic rotation of the first screw 210 and the second screw 220, thereby generating a stretching force field action mechanism, which can further effectively improve the dispersion and mixing effect of the multiphase material system and the melting efficiency.

[0045] It should be noted that the first screw 210, the second screw 220 and the barrel 100 form a flow channel 300, and the flow channel 300 is used for material passing.

[0046] It can be understood that the head ratio of the second screw 220 to the first screw 210 is inversely proportional to the speed ratio of the first screw 210 to the second screw 220.

[0047] It should be noted that the more the number of heads of the screw, the more stable the rotation, and therefore the number of head ratio and the rotation speed ratio are set to be inversely proportional, which can improve the meshing performance. For example, assuming that the rotation speed ratio of the first screw 210 to the second screw 220 is 2, the number of heads of the second screw 220 is 2, and the number of heads of the first screw 210 is 1.

[0048] It can be understood that the top diameter of the first screw 210 is the same as the top diameter of the second screw 220, and the root diameter of the first screw 210 is the same as the root diameter of the second screw 220.

[0049] It can be understood that the cross section of the first screw 210 and the second screw 220 corresponding to each meshing point is composed of an even number of circular arc segments and an even number of curve arc segments connected in alternation, and the radii of the circles corresponding to the two adjacent circular arc segments are the root diameter and the top diameter respectively. Each curve arc segment on the same cross section of the screw is a curve arc with a linearly changing central angle and the same change rate, and the two cross sections meshing with each other are symmetrically arranged along the connecting line of the two corresponding rotation centers.

[0050] It should be noted that the central angles of the circular arc segments corresponding to the same cross section of the screw are the same, and the "linearly changing central angle with the same change rate" means that the change rate of the central angle of the curve arc segment is the same along the top diameter to the root diameter. For example, for the second screw 220, the central angles of the circular arc segments on the second screw 220 are the same, and the curve arc segments are curve arcs with a linearly changing central angle and the same change rate.

[0051] It should be noted that the number of circular arc segments and the number of curve arc segments of the first screw 210 and the second screw 220 are not limited here. In some embodiments, the number of circular arc segments of the first screw 210 is the same as the number of circular arc segments of the second screw 220, and the number of curve arc segments of the first screw 210 is the same as the number of curve arc segments of the second screw 220, and the number of circular arc segments and the number of curve arc segments are independent of the rotation speed ratio. In other embodiments, the number of circular arc segments of the second screw 220 is k times the number of circular arc segments of the first screw 210, and the number of curve arc segments of the second screw 220 is k times the number of curve arc segments of the first screw 210, where k represents the rotation speed ratio of the first screw 210 to the second screw 220, and at this time, the number of circular arc segments and the number of curve arc segments are related to the rotation speed ratio.

[0052] It can be understood that the polar diameter of the curve arc segment of the first screw 210 corresponding to the first screw 210 is where θ is the central angle of the curve arc segment of the first screw 210, R is the top diameter, r is the root diameter, k is the rotation speed ratio of the first screw 210 to the second screw 220, and β is the maximum value of θ and the sum of the central angles of the adjacent circular arc segments is π.

[0053] For example, referring to Figure 3As shown, the polar radius represents the distance from the rotation center on the cross section to the corresponding curve arc segment. When θ is 0, the polar radius corresponds to the tip radius, and when θ is β, the polar radius is the root radius.

[0054] It should be noted that when the sum of β and the central angle corresponding to any one circular arc segment is π, the number of circular arc segments of the first screw 210 is set to 1, and the number of curve arc segments is also set to 1. The number of curve arc segments and the number of circular arc segments of the second screw 220 are not limited here. Referring to Figure 4 As shown, when the tip radius OB is located at the meshing point, the central angle θ linearly decreases in the counterclockwise direction when the first screw 210 rotates clockwise. It should be noted that for the second screw 220, in order to keep the plane formed by passing through the rotation axis 230 always meshing with the first screw 210, the polar radius change of the curve arc segment of the first screw 210 is opposite to that of the curve arc segment of the second screw 220.

[0055] It should be noted that referring to Figure 4 As shown, for the first screw 210, the value of the central angle of the circular arc segment can be determined according to actual conditions or gradually adjusted in geometric modeling construction. For this, the present embodiment does not limit the central angle of the first screw 210, as long as the above requirements are met.

[0056] It can be understood that the number of circular arc segments and curve arc segments of the second screw 220 is respectively set to k times the corresponding circular arc segments and curve arc segments of the first screw 210, and the corresponding polar radius of the curve arc segment of the second screw 220 is ρ(θ1) = r + (R-r)θ1 / β1, where θ1 is the central angle corresponding to the curve arc segment of the second screw 220, R is the tip radius, and r is the root radius; β1 is the maximum value of θ1, and β1 is The central angle corresponding to the circular arc segment of the second screw 220 is k is the speed ratio of the first screw 210 and the second screw 220.

[0057] It should be noted that β1 is the maximum central angle β of the curve arc segment of the first screw 210 The central angle corresponding to the circular arc segment of the second screw 220 is where the sum of the maximum central angle β1 of the m circular arc segments of the second screw 220 connected in turn and the central angle corresponding to the curve arc segment of the m second screw 220 is π, where m is half the number of circular arc segments of the second screw 220. For example, assuming that the number of circular arc segments and curve arc segments of the first screw 210 is set to 2, and the speed ratio k is set to 2, referring to Figure 4 and Figure 5As shown, the circular arc segments and the curve arc segments of the second screw 220 are respectively arranged as 4 segments, wherein the circular arc segments are A1B1, C1D1, E1F1, G1H1 respectively, and the curve arc segments are A1C1, D1E1, F1G1, H1B1 respectively. Among them, the central angles of the circular arc segments are all The maximum central angles of the curve arc segments are all β1, that is That is, for any circular arc segment of the second screw 220, it satisfies ρ(θ1) = r + (R-r)θ1 / β1, Wherein, O1D1 is R, O1A1 is r, and O1F1 is r.

[0058] It can be understood that the top diameters of the first screw 210 and the second screw 220 are tangent to the inner side wall of the barrel 100.

[0059] It should be noted that the top diameters of the first screw 210 and the second screw 220 are tangent to the inner side wall of the barrel 100, at this time, the first screw 210 and the second screw 220 can produce wedge decompression effect with the side wall of the barrel 100 at the meshing point position, and with the rotation of the screw, the periodic stretching force field is introduced to strengthen the dispersion mixing and accelerate the melting effect of the multi-phase system material.

[0060] It can be understood that the barrel 100 is sequentially provided with a conveying section 110, a melting section 120, an exhaust section 130 and a mixing and extruding section 140, and the first screw 210 and the second screw 220 penetrate through the conveying section 110, the melting section 120, the exhaust section 130 and the mixing and extruding section 140; The first screw 210 and the second screw 220 are both provided with a kneading structure 250, and the kneading structure 250 is located in the melting section 120.

[0061] It should be noted that referring to Figure 7 As shown, the use of kneading block structure can increase the stretching force field effect.

[0062] It should be noted that referring to Figure 6As shown, the feeding port 111 is arranged at one end of the conveying section 110 away from the melting section 120, the discharging port 141 is arranged at one end of the mixing extruding section 140 away from the exhaust section 130, the exhaust port 131 is arranged at the exhaust section 130, the first screw 210 and the second screw 220 rotate along the respective screw axes in the same direction in the conveying section 110, and the conveying force is generated through the friction and the positive displacement effect; the material moves to the melting section 120 under the combined action of the positive displacement conveying force and the friction between the two screws. In the melting section 120, the barrel 100 melts the material through external heating, meanwhile, the maximum speed difference caused by the engagement point located on the line connecting the rotation axes of the two screws strengthens the shear mixing effect of the engagement zone, provides more homoclinic points to start chaotic mixing, and the pulling field effect of the kneading structure 250 is increased, thereby strengthening the mixing and melting efficiency. In the exhaust section 130, the engagement zone is located in the plane composed of the axes of the two screws, the relative speed difference of the two screws in the engagement zone reaches the maximum, and a large stirring effect is generated on the material, which accelerates the exhaust efficiency and makes the exhaust gas discharged from the exhaust port 131. In the mixing extruding section 140, the first screw 210 and the second screw 220 rotate in the same direction, so that the first screw 210 and the second screw 220 have better pressure building capacity and extruding characteristics, and the plasticizing effect is strengthened under the action of the mixing mechanism described in the melting section 120, so that the material that becomes melt can be stably extruded from the discharging port 141.

[0063] It can be understood that the first screw 210 and the second screw 220 are arranged in the exhaust section 130 in the large lead structure.

[0064] It should be noted that the negative pressure space is generated by arranging the large lead structure, so that the exhaust efficiency can be further improved. It should be noted that the large lead structure means that the spacing between the adjacent two threads on the same screw is larger than that in other sections, and the specific structure of the large lead in the present application is not limited, and the person skilled in the art can arrange it according to the actual needs.

[0065] Next, two kinds of extruders of the embodiments of the present application are described with reference to Figure 1 , Figures 3 to 6 , Figure 8 and Figure 9 An extruder is described with reference to Figure 1 , Figures 3 to 6 , and the speed ratio of the first screw 210 and the second screw 220 is taken as an example. The extruder includes a barrel 100 and a screw assembly, the screw assembly includes one first screw 210 and two second screws 220, the first screw 210 and the second screw 220 are engaged, and the engagement point is located on the plane formed by the rotation axes 230 of the first screw 210 and the second screw 220, and the top diameter and the root diameter of the first screw 210 are engaged with the root diameter and the top diameter of the second screw 220 respectively to form a structure as shown in Figure 3The continuous Z-shaped line segments shown are connected to form a broken line 240. Figure 1 As shown, the number of heads of the second screw 220 is set to 2, the top diameter and the root diameter of the first screw 210 are respectively the same as the root diameter and the top diameter of the second screw 220, and referring to Figure 6 As shown, the first screw 210 and the second screw 220 are tangent to the inner wall of the barrel 100. Figure 4 and Figure 5 As shown, for any meshing point, the cross section corresponding to the first screw 210 is composed of two circular arc segments (AB and CD) and two curved arc segments (AD and BC) staggered together, wherein the circular arc segment AB and the circular arc segment CD correspond to the top diameter R and the root diameter r, respectively. For the curved arc segment AD, the central angle θ is determined by rotating clockwise with OA as the starting point, and the central angle θ is determined by rotating counterclockwise with OB as the starting point. At this time, the polar diameters corresponding to the central angles all satisfy the polar diameter. Wherein, k is 2. Correspondingly, for the second screw 220, Figure 4 The cross section of the first screw 210 is composed of 4 arc segments (A1B1, C1D1, E1F1, G1H1) and 4 curved arc segments (A1C1, D1E1, F1G1, H1B1). The arc segment E1F1 is meshed with the arc segment AB. The arc segment E1F1 corresponds to the root diameter r, and the polar diameter corresponding to the central angle θ1 of the curved arc segment between two adjacent arc segments satisfies ρ(θ1)=r+(Rr)θ1 / β1. Wherein, k is 2. At this time, refer to Figure 6As shown, in the conveying section 110, the first screw 210 and the second screw 220 rotate along the respective rotation axes 230 in the same direction, and the conveying force is generated by the friction and the positive displacement effect; under the combined action of the positive displacement conveying force and the friction between the two screws, the material moves in the direction of the melting section 120. In the melting section 120, the barrel 100 melts the material by external heating, and at the same time, the meshing point is located on the line connecting the centers of the two screws, so that the maximum speed difference can be generated at the meshing point, the shear mixing effect of the meshing area is strengthened, and more homoclinic points are provided to start chaotic mixing, thereby strengthening the mixing and melting efficiency. Under the action of external heating and the screw mechanism, the material finally becomes a melt, and then enters the exhaust section 130 under the push of the first screw 210 and the second screw 220. In the exhaust section 130, the first screw 210 and the second screw 220 adopt a large lead structure to generate a negative pressure space. Since the meshing area is located in the plane formed by the axes of the two screws, the relative speed difference of the two screws in the meshing area reaches the maximum, which produces a large stirring effect on the material, accelerates the exhaust efficiency, and makes the exhaust gas discharged from the exhaust port 131. At the same time, the material enters the mixing and extrusion section 140 under the push of the first screw 210 and the second screw 220. In the mixing and extrusion section 140, the first screw 210 and the second screw 220 rotate in the same direction, so that the first screw 210 and the second screw 220 have better pressure building capacity and extrusion characteristics. At the same time, under the action of the reinforced mixing mechanism described in the melting section 120, the mixing and plasticizing effect is strengthened, so that the material that has become a melt can be stably extruded from the discharge port 141.

[0066] For the extruder with a speed ratio of 1 between the first screw 210 and the second screw 220, since the main difference with the above-described extruder is the different arrangement of the circular arc segments and the curved arc segments in the cross section, only the different parts are described here. At this time, referring to Figure 8 and Figure 9 and combining Figure 1 and Figure 6 it can be seen that for any meshing point, the corresponding cross section of the first screw 210 and the second screw 220 is composed of two circular arc segments and two curved arc segments, wherein for the first screw 210, the circular arc segment AB and the circular arc segment DC correspond to the top diameter R and the root diameter r respectively; for the curved arc segments BC and AD between the two circular arc segments of the first screw 210, they both satisfy the polar radius Correspondingly, for the second screw 220, the circular arc segment E1F1 meshes with the circular arc segment AB, the circular arc segment E1F1 corresponds to the root diameter r, the other circular arc segment A1B1 corresponds to the top diameter R, and the polar radius of the curved arc segment between the two adjacent circular arc segments satisfies ρ(θ1)=r+(R-r)θ1 / β.

[0067] It should be noted that when the speed ratio is 2, the meshing effect is the best.

[0068] Referring toFigure 10 As shown, according to the extrusion processing method provided by the present application, the method is applied to the extruder as described above, and the method comprises the following steps:

[0069] In step S100, a rotation speed ratio of the first screw 210 and the second screw 220 is obtained.

[0070] In step S200, the first screw 210 and the second screw 220 are controlled to rotate at the rotation speed ratio in the same direction to transmit the material entering from the inlet of the barrel 100 to the outlet of the barrel 100 and process the material in the transmission process.

[0071] In step S300, the melting section 120 of the barrel 100 is monitored in real time in the transmission process.

[0072] In step S400, it is judged whether to adjust the heating power of the heating device arranged in the melting section 120 according to the result of the temperature monitoring.

[0073] The preferred embodiments of the embodiments of the present application are described above with reference to the accompanying drawings, and the scope of the right of the embodiments of the present application is not limited thereto. Any modification, equivalent replacement and improvement made by those skilled in the art without departing from the scope and essence of the embodiments of the present application shall be within the scope of the right of the embodiments of the present application.

Claims

1. An extruder characterized by, The extruder comprises: a barrel; a screw assembly comprising a first screw and a plurality of second screws, the first screw and the plurality of second screws rotate in the same direction and are arranged in the barrel, the first screw and the second screw are engaged and the engagement point is located in the plane formed by the rotation axes of the first screw and the second screw; the top diameter of the first screw and the root diameter of the second screw are engaged at the plane; the root diameter of the first screw and the top diameter of the second screw are engaged at the plane; the cross section of the first screw and the second screw corresponding to each engagement point is composed of an even number of circular arc segments and an even number of curve arc segments connected alternately, the radii of the circles corresponding to the adjacent two circular arc segments are the root diameter and the top diameter respectively; each curve arc segment on the same cross section of the screw is a curve arc with linearly changing central angle and the same change rate, and the two cross sections engaged with each other are symmetrically arranged along the connecting line of the two corresponding rotation centers.

2. The extruder of claim 1, wherein The ratio of the number of the second screw to the first screw is inversely proportional to the speed ratio of the first screw to the second screw.

3. The extruder of claim 1, wherein the top diameter of the first screw and the top diameter of the second screw are the same, and the root diameter of the first screw and the root diameter of the second screw are the same.

4. The extruder of claim 1, wherein The polar radius corresponding to the curved arc segment of the first screw wherein is the central angle corresponding to the curved arc segment of the first screw, is the top diameter, is the root diameter; is the speed ratio of the first screw to the second screw; the is the maximum value of the and the sum of the central angles corresponding to the adjacent circular arc segments is π.

5. The extruder of claim 1 or 4, wherein The number of the circular arc segments and the curve arc segments of the second screw rod is respectively set as times of the corresponding circular arc segments and curve arc segments of the first screw rod , wherein is the central angle of the curve arc segment of the second screw rod, is the top diameter, is the root diameter; the is the maximum value of the , and is the maximum central angle of the curve arc segment of the first screw rod , the central angle of the circular arc segment of the second screw rod is times of the central angle of the circular arc segment of the first screw rod; is the speed ratio of the first screw rod and the second screw rod.

6. The extruder of claim 1, wherein the top diameter of the first screw and the top diameter of the second screw are tangent to the inner side wall of the barrel.

7. The extruder of claim 1, wherein The barrel is sequentially provided with a conveying section, a melting section, a degassing section and a mixing and extruding section, the first screw and the second screw penetrate through the conveying section, the melting section, the degassing section and the mixing and extruding section; the first screw and the second screw are both provided with kneading structures, and the kneading structures are located in the melting section.

8. The extruder of claim 7, wherein The first screw and the second screw are arranged in the degassing section in a large lead structure.

9. An extrusion processing method characterized by, The method is applied to the extruder of any one of claims 1 to 8, and the method comprises: obtaining the speed ratio of the first screw and the second screw; controlling the first screw and the second screw to rotate in the same direction at the speed ratio to transmit the material entering from the barrel inlet to the barrel outlet and process the material during the transmission; during the transmission, monitoring the temperature of the melting section of the barrel in real time; judging whether to adjust the heating power of the heating device arranged in the melting section according to the temperature monitoring result.

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