CN113752520B

CN113752520B - Screw rod

Info

Publication number: CN113752520B
Application number: CN202111020034.3A
Authority: CN
Inventors: 刘彦昌
Original assignee: Wuxi Jinhe Technology Co ltd; Qingdao University of Science and Technology
Current assignee: Wuxi Quanjinhe Technology Co.,Ltd.; Qingdao University of Science and Technology
Priority date: 2021-09-01
Filing date: 2021-09-01
Publication date: 2023-04-14
Anticipated expiration: 2041-09-01
Also published as: CN113752520A

Abstract

The invention belongs to the technical field of extruders and discloses a screw. This screw rod includes the body of rod, the body of rod includes the feeding section, extrude section and mixed section, the feeding section with extrude the section and set up a feeding spiral arris and ejection of compact spiral arris that extend along body of rod axial spiral respectively at least, the mixed section sets up at the feeding section and extrudes between the section, the circumference equipartition along mixed section has four at least main spiral arris that extend along body of rod axial spiral, be provided with the protective screen spiral arris between two adjacent main spiral arris, at least one protective screen spiral arris can be connected with the feeding spiral arris, at least one protective screen spiral arris can be connected with ejection of compact spiral arris. This screw rod sets up the mixing section between feeding section and ejection of compact section, and the structure of mixing section can produce strong tensile flow, can show the mixing dispersion ability that increases the screw rod.

Description

Screw rod

Technical Field

The invention relates to the technical field of extruders, in particular to a screw.

Background

The recycling of the recycled plastic is one of the important ways of recycling resources, and has important effects on saving resources and protecting the environment. The production of the molded foamed sheet from the recycled plastic is one of the products reproduced from the recycled plastic.

At present, the production process of the recycled plastic molded foaming plate in a factory comprises the following steps: mixing by an internal mixer → serially connecting three open mills to perform thinly, cooling to obtain thin sheets → laminating → foaming by a flat plate die-pressing foaming machine → slicing. However, the process of preparing preformed sheet material using an open mill is inefficient, complex and laborious. Although the method for preparing the preformed sheet by melt extrusion can effectively overcome the defects of the method, the quality problems of unmelted hard particles or gels, low foaming ratio, uneven cell size and the like still exist after the preformed sheet prepared by recycled plastics is subjected to mould pressing and foaming, so that the screw structure in the prior art is known to have poor capability of dispersing and mixing the melted materials.

Therefore, a need exists for a screw that solves the problems of the prior art.

Disclosure of Invention

The invention aims to provide a screw, which can solve the problem that the screw in the prior art has poor capability of dispersing and mixing a molten material.

In order to achieve the purpose, the invention adopts the following technical scheme:

a threaded rod comprising a rod body, the rod body comprising:

the feeding section is arranged at one end of the rod body, and at least one feeding screw ridge spirally extending along the axial direction of the rod body is arranged on the feeding section;

the extrusion section is arranged at the other end of the rod body, and at least one discharging screw ridge spirally extending along the axial direction of the rod body is arranged on the extrusion section;

the mixing section sets up the feed zone with extrude between the section, follow on the mixing section the circumference equipartition of mixing section has four at least edges the main spiral arris that body of rod axial spiral extends, adjacent two be provided with the protective screen spiral arris between the main spiral arris, the one end and adjacent two of protective screen spiral arris one in the main spiral arris is connected near the one end of feed zone, the other end and adjacent two of protective screen spiral arris another one in the main spiral arris is connected near the one end of extruding the section, at least one on the mixing section the protective screen spiral arris can with the feed spiral arris is connected, at least one on the mixing section the protective screen spiral arris can with ejection of compact spiral arris is connected.

Optionally, the feeding section is provided with two feeding screw ridges with the same screw direction, screw pitch and screw ridge height, the extruding section is provided with two discharging screw ridges with the same screw direction and screw ridge height and different screw pitches as the feeding section, and the mixing section is provided with four main screw ridges with the same screw direction as the feeding section;

one end of any two adjacent barrier ribs, which is far away from the extrusion section, is connected with the feeding rib, and the other end of the barrier ribs, which is far away from the feeding section, is connected with the discharging rib.

Optionally, the barrier rib and one of two adjacent main ribs enclose an inlet groove, and an outlet groove is enclosed by the other of two adjacent main ribs, the width of the inlet groove gradually decreases from the feeding section to zero in the direction toward the extrusion section, and the width of the outlet groove gradually increases from zero in the direction toward the extrusion section from the feeding section.

Optionally, the height of the primary flight is 2mm to 6mm greater than the height of the barrier flight.

Optionally, the barrier flight includes first side inclined plane and second side inclined plane that extend along the screw direction, the top on first side inclined plane and second side inclined plane is close to each other and the bottom deviates from each other, first side inclined plane is located the inboard of screw direction, second side inclined plane is located the outside of screw direction, the inclination of first side inclined plane is greater than the inclination of second side inclined plane.

Optionally, the pitch of the feed section is greater than the pitch of the extrusion section.

Optionally, the helix angle of the primary screw flight is 14 ° to 29 ° less than the helix angle of the barrier screw flight.

Optionally, the body of rod still includes the connecting axle, the connecting axle with body of rod coaxial coupling, be provided with the keyway on the connecting axle.

The surface of the screw is provided with a nitriding layer, and the thickness of the nitriding layer is 0.5mm-0.7mm.

The invention has the beneficial effects that:

according to the invention, the mixing section is arranged at the feeding section and the extrusion section of the rod body, and the main spiral rib and the barrier spiral rib on the mixing section form a Z-shaped structure, so that high shear force can be provided, strong tensile flow is generated so as to disperse and shear unmelted solid particles or gel, and the mixing, dispersing and mixing capability of the screw is obviously improved.

Drawings

FIG. 1 is a schematic structural view of a screw provided by the present invention;

FIG. 2 is a schematic structural diagram of a mixing section of a screw provided by the present invention from a perspective;

FIG. 3 is a schematic view of the expanded configuration of the mixing section of the screw provided by the present invention in the axial direction;

FIG. 4 isbase:Sub>A schematic cross-sectional view of the barrier flight of FIG. 2 at A-A;

FIG. 5 is a schematic view of the mixing section of the screw of the present invention from another perspective;

fig. 6 is a schematic cross-sectional view of the main flight of fig. 5 at B-B.

In the figure:

1. a rod body; 11. a feeding section; 111. feeding screw edges; 12. an extrusion section; 121. discharging screw edges; 13. a mixing section; 131. a main screw edge; 1311. a third side bevel; 1312. a fourth side bevel; 132. a barrier flight; 1321. a first side bevel; 1322. a second side bevel; 133. an inlet screw groove; 134. an outlet screw groove;

2. a connecting shaft; 21. a keyway;

3. a barrel.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

In the description of the present invention, unless otherwise explicitly specified or limited, the terms "connected," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood in a specific case to those of ordinary skill in the art.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. "beneath," "under" and "beneath" a first feature includes the first feature being directly beneath and obliquely beneath the second feature, or simply indicating that the first feature is at a lesser elevation than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "left", "right", and the like are used based on the orientations and positional relationships shown in the drawings only for convenience of description and simplification of operation, and do not indicate or imply that the referred device or element must have a specific orientation, be configured and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used only for descriptive purposes and are not intended to have a special meaning.

Extruders are one of the class of plastics machines, and can be classified basically into twin-screw extruders, single-screw extruders and, less frequently, multi-screw extruders and screwless extruders.

The screw extruder depends on the pressure and the shearing force generated by the rotation of the screw, so that materials can be fully plasticized and uniformly mixed and are molded through a neck mold. The existing screw extruder has a simple structure, and when the existing screw extruder is used for preparing preformed plates from recycled plastics, the quality problems of unmelted hard particles or gel, low foaming ratio, uneven cell size and the like still exist after mould pressing and foaming. It is presumed that the poor dispersive mixing effect of the screw configuration of the melt extruder is a major cause of the quality defect of the foamed sheet produced by the extrusion preforming method.

In order to solve the problem of poor dispersion and mixing effects of screws in screw extruders in the prior art, a screw is provided in the embodiment.

As shown in fig. 1, the screw includes a rod body 1, a feeding section 11, an extruding section 12 and a mixing section 13 are arranged on the rod body 1, the feeding section 11 is arranged at one end of the rod body 1, the extruding section 12 is arranged at the other end of the rod body 1, and the mixing section 13 is arranged between the feeding section 11 and the extruding section 12 and is connected with the feeding section 11 and the extruding section 12, so as to ensure that the material in a molten state can be conveyed from the feeding section 11 to the extruding section 12 and extruded through a die.

Optionally, the feeding section 11 is provided with at least one feeding screw rib 111 spirally extending along the axial direction of the rod body 1, the extruding section 12 is provided with at least one discharging screw rib 121 spirally extending along the axial direction of the rod body 1, and the feeding screw rib 111 and the discharging screw rib 121 have the same spiral direction. At least four main screw ridges 131 spirally extending along the axial direction of the rod body 1 are uniformly distributed on the mixing section 13 along the circumferential direction of the mixing section 13, the main screw ridges 131 have the same spiral direction with the feeding screw ridges 111 and the discharging screw ridges 121, a barrier screw ridge 132 is arranged between two adjacent main screw ridges 131, one end of the barrier screw ridge 132 is connected with one end of one of the two adjacent main screw ridges 131 close to the feeding section 11, the other end of the barrier screw ridge 132 is connected with the other end of the two adjacent main screw ridges 131 close to the extruding section 12, at least one barrier screw ridge 132 on the mixing section 13 can be connected with the feeding screw ridge 111, at least one barrier screw ridge 132 can be connected with the discharging screw ridges 121, and the mixing section 13 is structurally arranged to enable a molten material to undergo multiple times of strong stretching flow and high shearing flow when passing through the mixing section 13, so that the mixing section 13 has high mixing capability and melting capability, the problem that hard particles exist in foaming prepared by a plastic foaming device can be solved, and the quality of plastic foaming plates can be improved.

Specifically, the number of the main ridges 131 on the mixing section 13 may be four or an even number greater than four, and different numbers of the main ridges 131 may be provided on the mixing section 13 according to the diameter of the rod body 1. When the diameter of the rod body 1 is 230mm, the feeding section 11 and the extruding section 12 are respectively provided with two feeding screw ridges 111 and two discharging screw ridges 121 which have the same screw direction and screw ridge height, the screw pitches of the feeding section 11 and the extruding section 12 are different, the mixing section 13 is provided with four main screw ridges 131 and four barrier screw ridges 132, and the spiral directions of the four main screw ridges 131 and the four barrier screw ridges 132 are the same as the spiral directions of the feeding screw ridges 111 and the discharging screw ridges 121. One end of any two adjacent barrier ribs 132 remote from the extrusion section 12 is connected to the feed rib 111, and the other end of the barrier ribs 132 remote from the feed section 11 is connected to the discharge rib 121. The Z-shaped screw ridge structure shown in figure 2 is formed in the mixing section 13, so that the mixing section 13 has lower pressure drop and higher conveying capacity, a stretching flow generation mechanism is applied to the Z-shaped screw ridge structure, and the material in a molten state is subjected to stretching flow and shearing flow in the mixing section 13, so that the unmelted hard particles or gel are dispersed, and the quality of the molded foaming board is improved.

The mixing section 13 in fig. 2 is developed along the axial direction to obtain the structure shown in fig. 3, and it can clearly see the zigzag screw rib structure formed by the main screw rib 131 and the barrier screw rib 132 of the mixing section 13, which can make the molten material receive strong stretching flow and high shearing flow for many times, disperse the unmelted gel or hard particles, and make the mixing section 13 have high mixing and melting ability.

The barrier rib 132 and one of its two adjacent main ribs 131 enclose an inlet groove 133, the opening of the inlet groove 133 faces the direction of the feeding section 11, and the other of the adjacent main ribs 131 encloses an outlet groove 134, the opening of the outlet groove 134 faces the direction of the extruding section 12. The width of inlet channel 133 decreases from feed zone 11 to zero in the direction of extrusion zone 12, and the width of outlet channel 134 increases from zero in the direction of extrusion zone 12 from feed zone 11. The molten material can be caused to reciprocate in the mixing section 13, increasing the mixing effect.

The inlet depth of inlet channel 133 decreases from feed zone 11 to zero in the direction of extrusion zone 12, and the depth of outlet channel 134 increases from zero in the direction of extrusion zone 12 from feed zone 11. The molten material can be allowed to pass over barrier flight 132 after entering mixing section 13 while the unmelted material is blocked by barrier flight 132, under the extensional and shear flow of mixing section 13, unmelted gel or hard particles are dispersed, pushed by main flight 131 over barrier flight 132, and into extrusion section 12.

Optionally, the height of the main screw ridges 131 is 2mm to 6mm higher than the height of the barrier screw ridges 132, and in this embodiment, the height of the main screw ridges 131 is 4mm higher than the height of the barrier screw ridges 132, so that the molten material can easily pass over the barrier screw ridges 132, and after the gel-like material is blocked by the barrier screw ridges 132, the gel-like material is dispersed under strong stretching flow and then passes over the barrier screw ridges 132, thereby improving the mixing and dispersing ability of the mixing section 13.

As shown in fig. 4, the barrier flight 132 includes a first side inclined surface 1321 and a second side inclined surface 1322 extending along the spiral direction, the top end of the first side inclined surface 1321 and the bottom end of the second side inclined surface 1322 are close to each other, that is, the first side inclined surface 1321 is located at the inner side of the spiral direction, the second inclined surface is located at the outer side of the spiral direction, the inclined angle of the first side inclined surface 1321 is larger than that of the second side inclined surface 1322, it can be understood that the first side inclined surface 1321 is a direction towards the extrusion section 12, the second side inclined surface 1322 is a direction towards the feeding section 11, and the broken line is a schematic sectional view of the barrel 3 along the axial direction of the rod body 1. The inclined angle of the first side inclined surface 1321 is larger than the inclined angle of the second side inclined surface 1322, so that a wedge gap is generated between the barrier flight 132 and the barrel 3, and a velocity gradient is generated when the molten material passes through the wedge gap from the feeding section 11 to the extruding section 12, so that a strong stretching flow is formed. And the molten material is also pushed by the helically shaped barrier ribs 132 as it passes through the wedge-shaped gap, so that the molten material is also subjected to shear forces, which subjects the molten material to high shear flow. Thus, dispersive mixing of the gel and further plasticating and melting can be achieved, ensuring that the extrusion section 12 is supplied with a completely molten material, ensuring the quality of the moulded foamed sheet after passing through the extrusion section 12.

The pitch of the feed zone 11 is greater than the pitch of the extrusion zone 12 to create a compression ratio in the barrel 3, the higher the compression ratio, the higher the extrusion ratio to which the molten material is subjected, and the better the quality of the moulded foamed sheet.

Optionally, the helix angle of the main flight 131 is 14 ° to 29 ° less than the helix angle of the barrier flight 132, the helix angle being the angle between the tangent to the helix of the flight and the cross-section of the shaft 1. In this embodiment, the helix angle of the main flight 131 is 31 °, and the helix angle of the barrier flight 132 is 50 °, so that the mixing section 13 has strong stretching ability and high shearing ability for the molten material.

Optionally, one end of the feeding section 11 on the rod body 1 is further provided with a connecting shaft 2, the connecting shaft 2 is coaxially connected with the rod body 1, a key groove 21 is formed in the connecting shaft 2, and the key groove 21 can be connected with the output end of the driving motor through a key.

As shown in fig. 5 and 6, the main screw rib 131 also includes a third inclined surface 1311 and a fourth inclined surface 1312, the third inclined surface is located at the inner side of the screw direction, the fourth inclined surface 1312 is located at the outer side of the screw direction, the third inclined surface 1311 is perpendicular to the rod body 1, the connection between the third inclined surface 1311 and the rod body 1 is rounded, the top end of the fourth inclined surface 1312 is close to the top end of the third inclined surface 1311, and the bottom end of the fourth inclined surface is far from the bottom end of the third inclined surface 1311, so that the main screw rib 131 has a high pushing force in the direction of the extrusion section 12.

Optionally, the surface of the screw in this embodiment is provided with a nitrided layer, the thickness of the nitrided layer is 0.5mm to 0.7mm, and the thickness of the nitrided layer in this embodiment is preferably 0.6mm, so that the abrasion resistance and the durability of the screw can be effectively improved.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Numerous obvious variations, adaptations and substitutions will occur to those skilled in the art without departing from the scope of the invention. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. Screw, characterized in that it comprises a shank (1), said shank (1) comprising:

the feeding section (11) is arranged at one end of the rod body (1), and at least one feeding screw rib (111) spirally extending along the axial direction of the rod body (1) is arranged on the feeding section (11);

the extruding section (12) is arranged at the other end of the rod body (1), and at least one discharging screw rib (121) spirally extending along the axial direction of the rod body (1) is arranged on the extruding section (12);

the mixing section (13) is arranged between the feeding section (11) and the extruding section (12), at least four main screw ridges (131) spirally extending along the axial direction of the rod body (1) are uniformly distributed on the mixing section (13) along the circumferential direction of the mixing section (13), a barrier screw ridge (132) is arranged between every two adjacent main screw ridges (131), one end of the barrier screw ridge (132) is connected with one end, close to the feeding section (11), of one of every two adjacent main screw ridges (131), the other end of the barrier screw ridge (132) is connected with one end, close to the extruding section (12), of the other of every two adjacent main screw ridges (131), at least one barrier screw ridge (132) on the mixing section (13) can be connected with the feeding screw ridge (111), and at least one barrier screw ridge (132) on the mixing section (13) can be connected with the discharging screw ridge (121);

the feeding section (11) is provided with two feeding screw ridges (111) with the same screw direction, screw pitch and screw ridge height, the extruding section (12) is provided with two discharging screw ridges (121) with the same screw direction and screw ridge height and different screw pitches as the feeding section (11), the screw pitch of the feeding section (11) is larger than that of the extruding section (12), and the mixing section (13) is provided with four main screw ridges (131) with the same screw direction as the feeding section (11);

one end of any two adjacent barrier ribs (132), which is far away from the extrusion section (12), is connected with the feeding rib (111), and the other end of the barrier ribs (132), which is far away from the feeding section (11), is connected with the discharging rib (121);

the barrier screw rib (132) comprises a first side inclined plane (1321) and a second side inclined plane (1322) which extend along the spiral direction, the top ends of the first side inclined plane (1321) and the second side inclined plane (1322) are close to each other and the bottom ends thereof deviate from each other, the first side inclined plane (1321) is located on the inner side of the spiral direction, the second side inclined plane (1322) is located on the outer side of the spiral direction, and the inclination angle of the first side inclined plane (1321) is greater than that of the second side inclined plane (1322).

2. Screw according to claim 1, wherein the barrier flight (132) encloses an inlet flight (133) with one of its two adjacent main flights (131) and an outlet flight (134) with the other of its two adjacent main flights (131), the width of the inlet flight (133) decreasing from the feed section (11) to zero in the direction of the extrusion section (12) and the width of the outlet flight (134) increasing from zero in the direction of the feed section (11) to the extrusion section (12).

3. Screw according to claim 2, wherein the inlet grooves (133) have an inlet depth which decreases progressively from the feed section (11) towards the extrusion section (12) to zero and the outlet grooves (134) have a depth which increases progressively from zero from the feed section (11) towards the extrusion section (12).

4. Screw according to claim 1, wherein the height of the main flight (131) is 2mm to 6mm higher than the height of the barrier flight (132).

5. Screw according to any one of claims 1 to 4, characterised in that the pitch of the feed section (11) is greater than the pitch of the extrusion section (12).

6. Screw according to any one of claims 1 to 4, wherein the helix angle of the main flight (131) is 14 ° to 29 ° smaller than the helix angle of the barrier flight (132).

7. Screw according to any one of claims 1 to 4, characterised in that the shank (1) further comprises a connecting shaft (2), the connecting shaft (2) being coaxially connected to the shank (1), the connecting shaft (2) being provided with a keyway (21).

8. A screw according to any one of claims 1 to 4, wherein a nitrided layer is provided on the surface of the screw, the nitrided layer having a thickness of from 0.5mm to 0.7mm.