Triangular body kneading block self-cleaning stirring device for devolatilization device

Abstract

This invention discloses a self-cleaning mixing device using triangular kneading blocks in a devolatilization apparatus. It includes triangular kneading components and a mixing shaft. Several triangular kneading components are equidistantly assembled along the axial direction of the mixing shaft. Each triangular kneading component consists of triangular kneading blocks and support plates. Each triangular kneading block includes a pointed end, two symmetrical inclined surfaces, two isosceles triangular cross-sections, and a base. The symmetrical inclined surfaces have grooves. The base of the triangular kneading block, pointing towards the axis, is embedded into the support plates through the grooves on both sides. Three to six triangular kneading blocks are embedded at the apex of the support plate edge of each triangular kneading component, making the cross-sectional shape of the component a regular polygon. The self-cleaning mixing device of this invention has a triaxial structure. The triaxial mixing device can rotate at the same speed or differential speed, exhibiting excellent mixing capacity and film-forming properties during rotation. The triangular kneading blocks between the two shafts periodically interlock during operation, achieving full-sealing and all-around self-cleaning during the process.

Description

Technical Field

[0001] This invention relates to a self-cleaning mixing device for triangular kneading blocks, specifically to a self-cleaning mixing device for triangular kneading blocks used in a devolatilization device. Background Technology

[0002] Many polymer materials commonly employ solution polymerization (e.g., PMMA, polyvinyl chloride, chlorinated nitrile rubber, etc.). Post-processing includes solvent devolatilization (solvent content can reach up to 95%). During high solvent devolatilization, as the solvent is continuously removed, the viscosity of the compound gradually increases, and some materials may even form a highly viscous state (viscosity 10). 6 For continuous devolatilization extrusion of high-solvent, high-viscosity materials (above mPa·s), conventional equipment, such as thin-film evaporators and drop-strip evaporators, cannot meet the devolatilization requirements of high-viscosity materials. Although single / twin-screw extruders can meet the devolatilization extrusion requirements of high-viscosity materials, they are not suitable for devolatilization extrusion operations of materials with high solvent content (above 30%).

[0003] The multi-shaft horizontal self-cleaning kneading-devouring extrusion equipment is a highly filled continuous devouring device capable of performing devouring of various high-solvent, high-viscosity materials. The kneading and stirring device is a crucial component for completing the devouring of high-solvent, high-viscosity materials.

[0004] To address the characteristics of devolatilization operations involving high-solvent, high-viscosity materials, a new stirring device is needed for use in horizontal devolatilization extrusion equipment. Summary of the Invention

[0005] To address the problem of difficult devolatilization of high-solvent, high-viscosity materials, this invention provides a triangular kneading block self-cleaning stirring device for use in devolatilization apparatuses.

[0006] This invention provides the following technical solution:

[0007] A self-cleaning stirring device for a triangular kneading block used in a devolatilization device includes a triangular kneading assembly and a stirring shaft. Several triangular kneading assemblies are equidistantly assembled along the axial direction of the stirring shaft. Each triangular kneading assembly consists of a triangular kneading block and a support plate. The triangular kneading block includes a pointed end, two symmetrical inclined surfaces, two isosceles triangular cross sections, and a base. The symmetrical inclined surfaces have grooves. The base of the triangular kneading block points towards the axis and is embedded into the support plate through the grooves on both sides, and is fixed by mechanical connection and welding. 3 to 6 triangular kneading blocks are embedded at the vertex of the support plate edge of each triangular kneading assembly, so that the cross-sectional shape of the assembly is a regular polygon.

[0008] Furthermore, there are 3 stirring shafts that can rotate at different speeds in the same direction. Each triangular kneading component has 4 or 5 triangular kneading blocks embedded at the apex of the support plate edge, so that the cross-sectional shape of the component is square or regular pentagon.

[0009] Furthermore, the outer diameter d of the stirring shaft and the outer diameter D of the self-cleaning stirring device are designed to range from 120 to 1500 mm.

[0010] Furthermore, the length-to-diameter ratio of the self-cleaning stirring device is L / D = 4:1 to 8:1, where L refers to the length of the effective part (working part) of the rotor.

[0011] Furthermore, the overall structure of the triangular kneading blocks in the same row on each shaft is spiral-shaped. The length of each triangular kneading block is determined according to the lead S. The angle β between each triangular kneading block and the axis is 5~20°. The larger the lead S, the smaller the angle β, and the longer the material residence time.

[0012] Furthermore, the top tip 102 of the triangular kneading block, the a-sloping surface and the b-sloping surface are symmetrically shaped contours. When the triangular kneading blocks between the two axes are running, they periodically interlock and connect to achieve a fully sealed and all-round self-cleaning effect.

[0013] Compared with the prior art, the beneficial effects of the present invention are:

[0014] (1) The self-cleaning stirring device is a three-axis structure. The three-axis stirring device can rotate at the same speed / differential speed. Several triangular kneading components are assembled at equal intervals along the stirring shaft. The triangular kneading components are composed of triangular kneading blocks and support plates. The triangular kneading blocks include a pointed head, two symmetrical inclined surfaces, two isosceles triangular sections and a base. The symmetrical inclined surfaces have grooves. The triangular kneading blocks are embedded in the support plates. When rotating, they have good mixing ability and film stretching ability. Combined with the characteristics of differential rotation, they can form a stable and continuous efficient interface renewal effect.

[0015] (2) The top tip of the triangular kneading block, the a-slope and b-slope are symmetrical slopes, which can make the triangular kneading blocks between the two shafts periodically interlock and dock during operation, and achieve full sealing and all-round self-cleaning in the process. This triangular kneading block self-cleaning stirring device can be installed in a horizontal reactor for continuous production of high solvent and high viscosity materials. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the present invention (the dashed box indicates the pinching or about-to-pinch area).

[0017] Figure 2 This is a cross-sectional view of the operation of the present invention (circles indicate the kneading or about-to-kneading area);

[0018] Figure 3 This is a top view of the invention in operation;

[0019] Figure 4A bar chart comparing the material residue rates of triangular kneading components and planar kneading components;

[0020] Figure 5 This is a comparison chart showing the relationship between the rotor speed and the tensile deformation of the material for a triangular kneading assembly and a planar kneading assembly.

[0021] In the diagram: 101, support plate; 102, pointed end; 103, inclined plane a; 104, inclined plane b; 105, first isosceles triangle section; 106, second isosceles triangle section; 107, base.

[0022] 201. First stirring shaft; 202. First shaft support plate.

[0023] 301. Second stirring shaft; 302. Second shaft support plate; 303. Second shaft triangular kneading block one; 304. Second shaft triangular kneading block two; 305. Rear support plate.

[0024] 401. Third stirring shaft; 402. Third shaft support plate; 403. Third shaft triangular kneading block one; 404. Third shaft triangular kneading block two;

[0025] 501. Machine barrel; 502. Machine barrel jacket. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Please see Figure 1-3 This invention discloses a triangular kneading block self-cleaning stirring device for use in a devolatilization apparatus, comprising a triangular kneading assembly and a stirring shaft. A plurality of triangular kneading assemblies are equidistantly assembled along the axial direction of the stirring shaft. Each triangular kneading assembly consists of a triangular kneading block and a support plate. The triangular kneading block includes a pointed end, two symmetrical inclined surfaces, two isosceles triangular cross-sections, and a base. Grooves are formed on the symmetrical inclined surfaces. The triangular kneading blocks are embedded in the support plate and fixed by mechanical connection and welding. Three to six triangular kneading blocks are embedded at the apex of the support plate edge of each triangular kneading assembly, making the cross-sectional shape of the assembly a regular polygon.

[0028] As attached Figure 1As shown, the triangular kneading block includes a pointed end 102, a bottom surface 107, an a-sloping surface 103, a b-sloping surface 104, a first isosceles triangular section 105, and a second isosceles triangular section 106. The overall structure is similar to a triangular prism. Grooves are opened on the a-sloping surface 103 and the b-sloping surface 104. The bottom surface 107 of the triangular kneading block points to the axis and is embedded into the support plate 101 through the grooves on both sides. It is fixed to the support plate 101 by mechanical connection and welding. This structure has good mixing ability and film stretching ability when rotating.

[0029] The pointed end 102, together with the inclined planes a and b, form a triangular prism-like structure that can be inserted into the interior of high-viscosity clump-like materials and stretch them during selective rotation to form a film-stretching effect.

[0030] Appendix Figure 1 The device has three stirring shafts that can rotate at different speeds in the same direction. Each stirring shaft has several triangular kneading components assembled at equal intervals along its axis. Four or five triangular kneading blocks are embedded at the apex of the support plate of each triangular kneading component, giving the component a square or regular pentagonal cross-sectional shape. This self-cleaning stirring device with triangular kneading blocks can be installed in a horizontal reactor for continuous production of high-solvent, high-viscosity materials undergoing devolatilization extrusion.

[0031] The number of kneaded blocks corresponds inversely to the speed ratio of the stirring shaft (the stirring shaft rotates at different speeds in the same direction). For example, if the speed ratio of two adjacent stirring shafts is 4:5, then the number of triangular kneaded blocks on the rotor is 5 / 4.

[0032] The outer diameter d of the stirring shaft and the outer diameter D of the self-cleaning stirring device are defined as follows: D has a design range of 120~1500mm. In other words, d refers to the outer diameter of the shaft (commonly known as the minor diameter), and D refers to the outer diameter of the entire stirring device (commonly known as the major diameter).

[0033] The length-to-diameter ratio of the self-cleaning agitator is L / D = 4:1~8:1, where L refers to the length of the effective part (working part) of the rotor.

[0034] Operating principle explanation:

[0035] The triangular kneading block has a pointed tip 102, and the a-sloping surface 103 and b-sloping surface 104 are symmetrically shaped, which allows the triangular kneading blocks between the two shafts to periodically interlock and connect during operation, achieving full sealing and all-round self-cleaning in the process.

[0036] The self-cleaning process is as follows:

[0037] As attached Figure 1As shown, when the machine is rotated to this position, a row of triangular kneading blocks on the second stirring shaft 301 will be about to collide with the support plate on the first stirring shaft 201; the second stirring shaft 301 and the third stirring shaft 401 each have a row of triangular kneading blocks that interlock and connect with each other through the gaps between them. Whenever the second stirring shaft 301 rotates 72° in the direction of rotation and the third stirring shaft 401 rotates 90°, the two shafts will perform such interlocking and connection once.

[0038] In this process, taking the triangular kneading block as an example, the tip of the second-axis triangular kneading block 303 scrapes against the surface of the third stirring shaft 401, while the tip of the third-axis triangular kneading block 404 scrapes against the surface of the second stirring shaft 301; the isosceles triangular cross section of the inner side of the second-axis triangular kneading block 303 scrapes against the surface of the third-axis support plate 402, and the two isosceles triangular cross sections of the third-axis triangular kneading block 404 scrapes against the second-axis support plate 302 and the rear support plate 305 on the second stirring shaft 301; at the same time, the bottom of the second-axis triangular kneading block 303 scrapes against the bottom of the third-axis triangular kneading block 404.

[0039] As attached Figure 2 As shown, when the machine is in this position, each of the first and second stirring shafts 201 and 301 has a row of triangular kneading blocks that interlock and connect with each other through gaps. The tip of the first triangular kneading block 303 on the second shaft scrapes against the surface of the first stirring shaft 201, while simultaneously, the tip of another row of triangular kneading blocks on the first stirring shaft 201 scrapes against the surface of the second stirring shaft 301. Furthermore, the outer cross-section of the isosceles triangle of the first triangular kneading block 403 on the third shaft is about to knead and scrape against the inner surface of the second shaft support plate 302, while the inner cross-section of the isosceles triangle of the second triangular kneading block 304 on the second shaft is about to knead and scrape against the outer surface of the third shaft support plate 402. In addition, in this operating position, besides the kneading blocks like the first and second triangular kneading blocks 303 and 304 that are interlocking between the two shafts, the tips of the other triangular kneading blocks are scraping against the inner wall of the barrel.

[0040] Through this process, repeated cyclically, periodic, fully sealed, and all-around self-cleaning is achieved. Combined with the characteristics of differential rotation, a stable and continuous high-efficiency interface renewal function can be formed.

[0041] like Figure 3As shown in the top view, the row of triangular kneading blocks on the single self-cleaning kneading and mixing device is not parallel to the axis, but rather forms a spiral shape. Observing a small section of the device, the line connecting the same row of triangular kneading blocks forms a certain spiral angle β with the axis, with β designed to range from 5 to 20°. To achieve efficient kneading and self-cleaning, the triangular kneading blocks in the same row are equidistantly separated, forming an independent, discontinuous structure. Because of β, the material can be propelled along the axial direction during rotation.

[0042] The lead S of the triangular kneading block represents the linear displacement of a point on the helix along the stirring shaft when the helix rotates once around the stirring shaft. The axial length of the triangular kneading block is usually determined by the lead S. For example... Figure 3 As shown, the lead S is negatively correlated with the helix angle β: the larger the lead S, the smaller the corresponding helix angle β. In actual production, the design of the helix angle β needs to be optimized according to the material residence time requirements. A smaller helix angle β will prolong the residence time of the material in the kneading block area, and vice versa.

[0043] As attached Figure 2 As shown, during the rotation, it can be observed that due to the presence of the included angle β and the lead S, the rotation is achieved through the attached... Figure 2 When observing the cross-sectional views of other support plates and their kneading blocks, they are not completely obscured by the cross-sectional views of the first axial support plate 202, the second axial support plate 302, and the third axial support plate 402 of the triangular kneading assembly, but instead present a "ghosting" visual image.

[0044] Table 1 Comparison of Triangular Pinch Components and Planar Pinch Components

[0045] project Triangular kneading components planar kneading components Operating mode Same direction full meshing Same direction full meshing Self-cleaning function All-round self-cleaning function Unable to clean the back Suitable for material viscosity range High viscosity Medium and high viscosity materials Stretching and mixing capabilities outstanding generally

[0046] The table above demonstrates that the triangular kneading component has a better self-cleaning function.

[0047] Figure 4 As shown in the bar chart, the material residue rate of the triangular kneading assembly and the planar kneading assembly are compared. The material residue rate of the triangular kneading assembly is lower than that of the planar kneading assembly at both the barrel and the rotor.

[0048] Figure 5 As shown in the figure, the rotor speed of the triangular kneading assembly and the planar kneading assembly are compared with the tensile deformation of the material. The tensile and mixed deformation of the triangular kneading assembly is greater than that of the planar kneading assembly.

[0049] This device employs a flow-channel-type heat medium heating system design. A heat medium circulation channel is installed inside the stirring shaft, connecting to an external heat medium (such as heat transfer oil / steam / hot water) heating system via heat medium inlet and outlet pipes on the stirring shaft. Each triangular kneading assembly has its own internal heat medium flow channel structure, forming an independent heat medium circulation loop. This heating structure achieves uniform surface temperature distribution while effectively increasing the heat exchange area of ​​the device surface, thus improving the heat transfer efficiency between the device and the material.

[0050] This self-cleaning agitator features a triaxial structure, capable of rotating at the same or differential speeds. It boasts highly efficient interface renewal and self-cleaning capabilities, as well as kneading and mixing abilities, along with high torque transmission and mass transfer capabilities. This self-cleaning agitator is suitable for high-viscosity materials and highly elastic solid-phase materials, and allows for stable and continuous production.

[0051] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A triangular kneading block self-cleaning stirring device used in a devolatilization apparatus, characterized in that: The device includes a triangular kneading assembly and a stirring shaft. Several triangular kneading assemblies are equidistantly assembled along the axial direction of the stirring shaft. Each triangular kneading assembly consists of a triangular kneading block and a support plate. The triangular kneading block includes a pointed end, two symmetrical inclined surfaces, two isosceles triangular cross sections, and a base. The symmetrical inclined surfaces have grooves. The base of the triangular kneading block points towards the axis and is embedded into the support plate through the grooves on both sides, and is fixed by mechanical connection and welding. 3 to 6 triangular kneading blocks are embedded at the vertex of the support plate edge of each triangular kneading assembly, so that the cross-sectional shape of the assembly is a regular polygon.

2. The triangular kneading block self-cleaning stirring device for a devolatilization device according to claim 1, characterized in that: There are 3 stirring shafts that can rotate at different speeds in the same direction. 4 / 5 triangular kneading blocks are embedded at the apex of the support plate of each triangular kneading component, so that the cross-sectional shape of the component is square or regular pentagon.

3. The triangular kneading block self-cleaning stirring device for a devolatilization device according to claim 1, characterized in that: The outer diameter d of the stirring shaft and the outer diameter D of the self-cleaning stirring device are designed to be within the range of 120~1500mm.

4. The triangular kneading block self-cleaning stirring device for a devolatilization device according to claim 1, characterized in that: The length-to-diameter ratio of the self-cleaning stirring device is L / D = 4:1 to 8:1, where L refers to the length of the effective part of the rotor.

5. A triangular kneading block self-cleaning stirring device for a devolatilization device according to claim 1, characterized in that: The overall structure of the triangular kneading blocks in the same row on each shaft is spiral-shaped. The length of each triangular kneading block is determined by the lead S. The angle β between each triangular kneading block and the axis is 5~20°. The larger the lead S, the smaller the angle β, and the longer the material residence time.

6. The triangular kneading block self-cleaning stirring device for a devolatilization device according to claim 1, characterized in that: The triangular kneading block has a pointed tip (102), a inclined plane (103) and b inclined plane (104) with symmetrical inclined plane outlines. The triangular kneading blocks between the two axes periodically interlock and connect during operation to achieve full sealing and all-round self-cleaning.

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