CN-117325427-B - Homodromous double-screw extruder with rotation speed ratio periodically changed and processing method thereof

CN117325427BCN 117325427 BCN117325427 BCN 117325427BCN-117325427-B

Abstract

The invention discloses a homodromous double-screw extruder with a periodically-changed rotation speed ratio and a processing method thereof, wherein the homodromous double-screw extruder with the periodically-changed rotation speed ratio comprises a machine barrel and a screw mechanism, the machine barrel adopts an 8-shaped structure with mutually parallel cylindrical holes, the screw mechanism is positioned in the machine barrel and comprises a first screw and a second screw, the first screw and the second screw rotate in the same direction, the average rotation speeds of the first screw and the second screw are equal, the rotation speeds of the first screw and the second screw are periodically changed in a pulsation manner along with time, the period of the pulsation change is the same, the first screw and the second screw are always meshed and rotated in the running process, the self-cleaning function is realized, the introduction of the periodic transient disturbance effect is enhanced, the efficiency of strengthening melting, mixing and exhausting is particularly suitable for low-temperature processing of a strongly dispersed multiphase material system.

Inventors

XU BAIPING
WU GUIQUN
YU HUIWEN
Tan Lingcao
XIAO SHUPING
HUANG JIARONG
XU WENHUA

Assignees

五邑大学

Dates

Publication Date: 20260508
Application Date: 20230814

Claims (9)

1. A co-rotating twin screw extruder having a periodically varying rotation speed ratio, comprising: the machine barrel adopts a 8-shaped structure with mutually parallel cylindrical holes; The screw rod mechanism is located in the machine barrel, the screw rod mechanism comprises a first screw rod and a second screw rod, the first screw rod and the second screw rod rotate in the same direction, the average rotating speed of the first screw rod and the average rotating speed of the second screw rod are equal, the rotating speeds of the first screw rod and the second screw rod change in a periodic pulsation mode along with time, the period of the pulsation change is the same, the first screw rod and the second screw rod are meshed with each other all the time in the operation process, the first screw rod and the second screw rod rotate in the same direction, the angular speed of the screw rod is set to be the rotating speed, and the rotating speed of the first screw rod is: 1 = 0 (1+ sin(2π 0 t/α)), 0 Is an average angular velocity of 0< 0 <50000; Is the rotational speed disturbance amplitude of the first screw rod and 0 1;T is time, the top angle of the first screw and the second screw is alpha, and the rotating speed of the second screw is: 2 = 0 (1- sin(2π 0 t/α)), Is the rotation speed disturbance amplitude of the second screw rod and 0 1, The rotation speed ratio of the first screw to the second screw is (1 +) sin(2π 0 t/α))/ (1- sin(2π 0 t/α))。
2. The co-rotating twin screw extruder of claim 1, wherein the rotation center of the first screw is O, the top diameter and the root diameter of the first screw are each composed of an arc AB and an arc CD, the radii of the arc AB and the arc CD are R, r, respectively, the corresponding central angles are α, the top diameter and the root diameter of the first screw are connected by a curved arc, the corresponding central angles are β, given integers k, k=1, 2,..100, α= β= The center of rotation of the second screw is O 1 , the top diameter and the root diameter of the second screw are both composed of an arc A 1 B 1 and an arc C 1 D 1 , the radiuses of the arc A 1 B 1 and the arc C 1 D 1 are R, r respectively, the corresponding central angles are alpha, the top diameter and the root diameter of the second screw are connected by adopting curve arcs, the corresponding central angles are beta, and the center distance C between the first screw and the second screw is: C=2Rcos(β/2) the radius r of the first screw and the second screw satisfies the following relationship: r=2Rcos(β/2)-R The top diameter and the root diameter of the first screw are connected by adopting a curve arc BC, the connection rotation center O and the root diameter starting point B are used as the polar diameter starting position Ox, the anticlockwise direction is positive, and the corresponding polar angle of any position of the BC arc is given by an auxiliary angle theta The polar diameter is , = Wherein, the ,CD、 Is an arc with radius R, CD, The corresponding central angle is alpha, AB, Is an arc with radius r, AB, The corresponding central angle is also alpha, and the curved arcs BC and ; A curve arc is adopted between the top diameter and the root diameter of the first screw rod Connecting the rotation center O and the root diameter starting point As the initial position O of the polar diameter Clockwise positive, given an auxiliary angle θ The corresponding polar angle of any arc position is The polar diameter is , = Wherein, the , And The rotation center O is in central symmetry relation, and the corresponding central angles are beta, AB, BC, CD, 、、、 Forming a closed curve arc to form an end face of the first screw thread element.
3. The co-rotating twin screw extruder of claim 1, wherein the total axial dimension of the flighted elements of the first screw is L, mm, 0.5L or less, given a parameter t, the z-coordinate of any cross section of the flighted elements satisfies: Wherein, the At the same time, AB, BC, CD, 、、、 The end surfaces of the threads are formed to seal a curve arc and rotate around the rotation center clockwise or anticlockwise by an angle The method comprises the following steps: 。
4. The co-rotating twin screw extruder of claim 3, wherein the top diameter and the root diameter of the second screw are connected by a curved arc B 1 C 1 , the connecting rotation center O 1 and the root diameter starting point B 1 are used as the polar diameter starting position O 1 x 1 , the counter-clockwise rotation is positive, and given the auxiliary angle θ, the polar angle corresponding to any position of the arc B 1 C 1 is The polar diameter is , = Wherein, the ,C 1 D 1 、 Is an arc with radius R, the corresponding central angle is alpha, A 1 B 1 , The radius is an arc with r, the corresponding central angle is alpha, and the curve arc B 1 C 1 , Regarding the rotation center O 1 as a central symmetry relationship, the corresponding central angles are beta; A curve arc is adopted between the top diameter and the root diameter of the second screw rod Connecting the rotation center O 1 and the root diameter starting point A 1 as the polar diameter starting position O Clockwise positive, given an auxiliary angle θ The corresponding polar angle of any arc position is The polar diameter is , = Wherein, the , And With respect to the rotation center O 1 as a central symmetry relationship, the corresponding central angles are beta, A 1 B 1 、B 1 C 1 、C 1 D 1 , 、、、、 Forming a closed curve arc to form the end face of the second screw thread element.
5. The co-rotating twin screw extruder of claim 4, wherein the flighted elements of the second screw have an overall axial dimension of L, mm, Given the parameter t, the z-coordinate of any section of the threaded element satisfies: Wherein, the ,A 1 B 1 、B 1 C 1 、C 1 D 1 、、、、、 The end face of the second screw rod is closed to form a curve arc, and the curve arc rotates clockwise or anticlockwise around the rotation center The method comprises the following steps: 。
6. the co-rotating twin screw extruder of claim 1, wherein the top diameters of the first and second screws are tangential to the inner cavity wall of the barrel.
7. The co-rotating double-screw extruder with the periodically-changing rotation speed ratio according to claim 1, wherein the screw mechanism sequentially divides the inner cavity of the machine barrel into a conveying section, a melting section, an exhaust section and a mixing extrusion section, a feed inlet is arranged on the machine barrel corresponding to the conveying section, an exhaust port is arranged on the machine barrel corresponding to the exhaust section, and a discharge port is arranged at the tail end of the machine barrel corresponding to the mixing extrusion section.
8. The co-rotating twin screw extruder of claim 1, wherein the screw mechanism further comprises a third screw having the same structure as the first screw, the third screw being intermeshed with the second screw at all times, and the third screw and the first screw being identical in rotation.
9. A method for processing a co-rotating twin-screw extruder having a periodically varying rotation speed ratio, characterized by being applied to the co-rotating twin-screw extruder having a periodically varying rotation speed ratio as claimed in any one of claims 1 to 8, comprising: Adding materials; The first screw and the second screw rotate in the same direction, the rotation speeds of the first screw and the second screw change periodically along with time, the average rotation speeds of the first screw and the second screw are the same, the pulsation period and the pulsation amplitude of the rotation speeds of the first screw and the second screw are the same, and the material is propelled to move forwards through the first screw and the second screw; The materials are melted by heat generated by rotation of the first screw and the second screw and external heating, and extrusion stretching effect can be generated in a meshing zone due to periodic transient disturbance effect in the process so as to accelerate the melting process of the materials to form melt; and mixing and pressure building are carried out under the periodic transient disturbance action through the first screw, the second screw and the machine barrel, and finally extrusion molding is carried out from an outlet.

Description

Homodromous double-screw extruder with rotation speed ratio periodically changed and processing method thereof Technical Field The embodiment of the invention relates to the technical field of double-screw extruders, in particular to a homodromous double-screw extruder with a periodically-changed rotation speed ratio and a processing method thereof. Background At present, the homodromous double-screw extruder is widely applied to the fields of new materials, foods, medicines, chemical industry and the like, but along with higher and higher requirements of high-speed high-efficiency low-temperature extrusion, the melting plasticizing and mixing effects of the traditional homodromous double-screw extruder are also more and more difficult to meet the requirements, so that the technical problem to be solved is how to further improve the melting plasticizing and mixing effects of the homodromous double-screw extruder. Disclosure of Invention The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims. The embodiment of the invention provides a homodromous double-screw extruder with a periodically-changed rotation speed ratio and a processing method thereof, wherein the rotation speeds of two screws are periodically changed along with time, the average speeds are equal, the rotation speed pulsation periods are the same, left and right screws show periodic alternation of left and right, and the periodic transient disturbance effect is introduced to strengthen the melt mixing, so that the melt plasticizing and mixing effects of the homodromous double-screw extruder can be further improved, and the two screws are always meshed with each other to realize a self-cleaning function. A first aspect of an embodiment of the present invention provides a co-rotating twin-screw extruder having a rotation speed ratio periodically varying, comprising: the machine barrel adopts a 8-shaped structure with mutually parallel cylindrical holes; The screw rod mechanism is located in the machine barrel, the screw rod mechanism comprises a first screw rod and a second screw rod, the first screw rod and the second screw rod rotate in the same direction, the average rotating speeds of the first screw rod and the second screw rod are equal, the rotating speeds of the first screw rod and the second screw rod are periodically pulse-changed along with time, the pulse-changed periods are the same, and the first screw rod and the second screw rod are meshed with each other all the time in the operation process. In some embodiments, the first screw and the second screw rotate in the same direction, and the angular velocity of the first screw is set to:1=0(1+ε1sin(2π0 t/alpha)) is the rotational speed of one screw, 0 Is an average angular velocity of 0<0<50000;ε1 Is the rotational speed disturbance amplitude of the first screw rod and 01;T is time, alpha is the top angle of the screw, and the rotating speed of the second screw is as follows:2=0(1-sin(2π0t/α)),ε2 Is the rotation speed disturbance amplitude of the second screw rod and 0 1, The rotation speed ratio of the first screw to the second screw is (1 +)sin(2π0t/α))/ (1-sin(2π0t/α))。 In some embodiments, the rotation center of the first screw is O, the top diameter and the root diameter of the first screw are each composed of an arc AB and an arc CD, the radii of the arc AB and the arc CD are R, r, respectively, the corresponding central angles are α, the top diameter and the root diameter of the first screw are connected by adopting a curve arc, the corresponding central angles are β, given an integer k, k=1, 2, 100, α= β= The center of rotation of the second screw is O 1, the top diameter and the root diameter of the second screw are both composed of an arc A 1B1 and an arc C 1D1, the radiuses of the arc A 1B1 and the arc C 1D1 are R, r respectively, the corresponding central angles are alpha, the top diameter and the root diameter of the second screw are connected by adopting curve arcs, the corresponding central angles are beta, and the center distance C between the first screw and the second screw is: C=2Rcos(β/2) The screw inner diameters r of the first screw and the second screw satisfy the following relationship: r=2Rcos(β/2)-R The top diameter and the root diameter of the first screw are connected by adopting a curve arc BC, the connection rotation center O and the root diameter starting point B are used as the polar diameter starting position Ox, the anticlockwise direction is positive, and the corresponding polar angle of any position of the BC arc is given by an auxiliary angle theta 1 (Θ) electrode diameter is, 1(θ)= At this time, the liquid crystal display device,Wherein, CD,Is an arc with radius R, CD,The corresponding central angle is alpha, AB,Is an arc with radius r, AB,The corresponding central angle is also alpha, and the curved arcs BC and; A curve arc is adopted between the top diameter and t