CN113752520B - a screw - Google Patents

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

a screw

technical field

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

Background technique

The recycling of plastics is one of the important ways of resource recycling, which plays an important role in resource conservation and environmental protection. Making recycled plastic into molded foam board is one of the products that are recycled from recycled plastic.

At present, the production process of recycling plastic molded foamed sheets in the factory is: mixing with internal mixer → three open mixers connected in series for thin pass preforming → cooling out thin sheets → stacking sheets → foaming with flat molded foaming machine → slicing. However, the method of preparing preformed boards with an open mill is low in production efficiency, complicated and laborious. And the method for preparing preformed sheet material with melt extrusion, although can effectively overcome the defective of above-mentioned method, for the reclaimed plastics preparation preformed sheet material still exists unmelted hard particle or gel, foaming ratio after molding foaming. Low and non-uniform cell size and other quality problems, therefore, it can be known that the ability of the screw structure in the prior art to disperse and mix molten materials is poor.

Therefore urgently need a kind of screw rod to solve the problem in the prior art.

Contents of the invention

The purpose of the present invention is to provide a screw, which can solve the problem of poor ability of the screw to disperse and mix molten materials in the prior art.

For reaching this purpose, the present invention adopts following technical scheme:

A kind of screw rod, comprises rod body, and described rod body comprises:

The feeding section is arranged at one end of the rod body, and the feeding section is provided with at least one feeding flight helically extending along the axial direction of the rod body;

The extrusion section is arranged at the other end of the rod body, and the extrusion section is provided with at least one discharge flight helically extending along the axial direction of the rod body;

The mixing section is arranged between the feeding section and the extrusion section, and the mixing section is uniformly distributed along the circumferential direction of the mixing section with at least four main screw ribs extending helically along the axial direction of the rod body. A barrier flight is arranged between two adjacent main flights, one end of the barrier flight is connected to one end of one of the two adjacent main flights which is close to the feed section, and the barrier flight The other end is connected to an end close to the extrusion section of the other of the adjacent two main screw flights, at least one barrier screw flight on the mixing section can be connected to the feed screw flight, and the mixing section At least one of the barrier flights can be connected to the discharge flight.

Optionally, the feed section is provided with two feed flights with the same screw direction, screw pitch and flight height, and the extrusion section is set with the same screw direction and flight height as the feed section, and the screw pitch is the same as that of the feed section. For the two different discharge flights, the mixing section is provided with four main flights with the same helical direction as the feed section;

One of the ends of any two adjacent barrier flights away from the extrusion section is connected to the feed flight, and the other end of the barrier flight away from the feed section is connected to the outlet section. Material screw connection.

Optionally, the barrier flight encloses an inlet flight channel with one of the two adjacent main flight flights, and forms an outlet flight channel with the other of the two adjacent main flight flights, The width of the inlet screw groove gradually decreases to zero from the direction of the feed section towards the extrusion section, and the width of the outlet screw groove gradually decreases from zero to zero from the direction of the feed section towards the extrusion section. increase.

Optionally, the height of the main flight is 2mm-6mm higher than the height of the barrier flight.

Optionally, the barrier flight includes a first side slope and a second side slope extending along the helical direction, top ends of the first side slope and the second side slope are close to each other and bottom ends are away from each other, the first The side bevel is located inside the helical direction, the second side bevel is located outside the helix direction, and the inclination angle of the first side bevel is greater than the inclination angle of the second side bevel.

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

Optionally, the helix angle of the main flight is 14°-29° smaller than the helix angle of the barrier flight.

Optionally, the rod body further includes a connecting shaft, the connecting shaft is coaxially connected with the rod body, and key grooves are arranged on the connecting shaft.

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

Beneficial effects of the present invention:

In the present invention, a mixing section is arranged in the feeding section and the extrusion section of the rod body, and the main screw flight and the barrier screw flight on the mixing section form a Z-shaped structure, which can provide high shear force, thereby generating strong tensile flow for dispersing shear Unmelted solid particles or gels significantly improve the mixing and dispersing capabilities of the screw.

Description of drawings

Fig. 1 is the structural representation of screw rod provided by the present invention;

Fig. 2 is a schematic view of the structure of the mixing section of the screw provided by the present invention under a viewing angle;

Fig. 3 is a schematic structural view of the expansion of the mixing section of the screw provided in the present invention along the axial direction;

Fig. 4 is a schematic diagram of the cross-sectional structure of the barrier helix at A-A in Fig. 2;

Fig. 5 is a structural schematic diagram of the mixing section of the screw provided by the present invention under another viewing angle;

Fig. 6 is a schematic cross-sectional structure diagram of the main flight in Fig. 5 at B-B.

In the picture:

1. Rod body; 11. Feed section; 111. Feed flight; 12. Extrusion section; 121. Discharge flight; 13. Mixing section; 131. Main flight; 1311. Third side bevel; 1312. The fourth side slope; 132, the barrier screw edge; 1321, the first side slope; 1322, the second side slope; 133, the inlet screw groove; 134, the outlet screw groove;

2. Connecting shaft; 21. Keyway;

3. Barrel.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention. In addition, it should be noted that, for the convenience of description, only some structures related to the present invention are shown in the drawings but not all structures.

In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected" and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integrated ; It can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediary, and it can be the internal communication of two components or the interaction relationship between two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations.

In the present invention, unless otherwise clearly specified and limited, a first feature being "on" or "under" a second feature may include direct contact between the first and second features, and may also include the first and second features Not in direct contact but through another characteristic contact between them. Moreover, "above", "above" and "above" the first feature on the second feature include that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature. "Below", "beneath" and "under" the first feature to the second feature include that the first feature is directly below and obliquely below the second feature, or simply means that the first feature has a lower level than the second feature.

In the description of this embodiment, the terms "up", "down", "left", "right" and other orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operations. It is not intended to indicate or imply that the referred device or element must have a particular orientation, be constructed in a particular orientation, and operate in a particular orientation, and thus should not be construed as limiting the invention. In addition, the terms "first" and "second" are only used to distinguish in description, and have no special meaning.

Extruder is one of the types of plastic machinery. Extruders can be basically classified into twin-screw extruders, single-screw extruders, and rare multi-screw extruders and non-screw extruders.

The screw extruder relies on the pressure and shear force generated by the rotation of the screw, so that the material can be fully plasticized and evenly mixed, and then formed through the die. The existing screw extruder has a simple structure. When it is used to prepare preformed sheets from recycled plastics, there are still unmelted hard particles or gels, low expansion ratios, and uneven cell sizes after molding and foaming. question. It can be speculated that the poor dispersion and mixing effect of the screw configuration of the melt extruder is the main reason for the quality defects of the foamed sheet prepared by the extrusion preforming method.

In order to solve the problem of poor dispersion and mixing effect of the screw in the screw extruder in the prior art, a screw is provided in this embodiment.

As shown in Figure 1, the screw rod includes a rod body 1, and the rod body 1 is provided with a feed section 11, an extrusion section 12 and a mixing section 13, the feed section 11 is arranged at one end of the rod body 1, and the extrusion section 12 is arranged at the end of the rod body 1 At the other end, the mixing section 13 is arranged between the feed section 11 and the extrusion section 12, and is connected with the feed section 11 and the extrusion section 12, so as to ensure that the material in the molten state can be transferred from the feed section 11 to the extrusion section 12 and extruded through the die.

Optionally, the feed section 11 is provided with at least one feed screw flight 111 extending helically along the axial direction of the rod body 1 , and the extrusion section 12 is provided with at least one discharge flight flight helically extending along the axial direction of the rod body 1 121, the screw direction of the feeding screw 111 and the discharging screw 121 are the same. At least four main screw flights 131 extending helically along the axial direction of the rod body 1 are evenly distributed on the mixing section 13 along the circumferential direction of the mixing section 13. A barrier flight 132 is arranged between the two main flights 131, one end of the barrier flight 132 is connected to one end of one of the adjacent two main flights 131 near the feed section 11, and the other end of the barrier flight 132 One end is connected with another end of the adjacent two main screw ribs 131 near the extrusion section 12, and at least one barrier screw rib 132 can be connected with the feed screw rib 111 on the mixing section 13, at least one barrier screw rib 132 can Connected with the discharge screw flight 121, the configuration of the mixing section 13 can make the molten material undergo multiple strong tensile flows and high shear flows when passing through the mixing section 13, ensuring that the mixing section 13 has efficient mixing capabilities and The melting ability can solve the problem of hard particles in the foamed sheet prepared by the plastic foaming equipment, and improve the quality of the plastic molded foamed sheet.

Specifically, the number of main flight 131 on the mixing section 13 can be four or an even number greater than four, and different numbers of main flight 131 can 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 feed section 11 and the extrusion section 12 are respectively provided with two feed screw flights 111 and two discharge screw flights 121 with the same screw direction and flight height, and the feed section 11 and The screw pitch of the extrusion section 12 is different, and the mixing section 13 is provided with four main screw flights 131 and four barrier screw flights 132. It is the same as the spiral direction of the discharge screw rib 121. One of any two adjacent barrier flights 132 is connected to the feed flight 111 at the end far away from the extrusion section 12 , and the other barrier flight 132 is connected to the discharge flight 121 at the end far away from the feed section 11 . In the mixing section 13, a "Z"-shaped screw flight structure as shown in Figure 2 is formed, so as to ensure that the mixing section 13 has a lower pressure drop and higher delivery capacity, and the extensional flow generation mechanism is applied to the "Z"-shaped In the helicoid structure, the material in the molten state is subjected to stretching flow and shear flow in the mixing section 13, so as to disperse unmelted hard particles or gels and improve the quality of the molded foam board.

Expand the mixing section 13 in Fig. 2 along the axial direction to obtain the structure shown in Fig. 3, and you can clearly see the "Z"-shaped flight formed by the main flight 131 and the barrier flight 132 of the mixing section 13 structure, the helicoid structure can make the molten material subjected to strong tensile flow and high shear flow for many times, disperse unmelted gel or hard particles, and make the mixing section 13 have efficient mixing and melting capabilities.

One of the two adjacent main screw ribs 131 of the barrier screw rib 132 encloses an inlet screw groove 133, and the opening of the inlet screw groove 133 faces the direction of the feed section 11 and is surrounded by another adjacent main screw rib 131. The outlet screw groove 134 , the opening of the outlet screw groove 134 faces the direction of the extrusion section 12 . The width of the inlet screw groove 133 gradually decreases to zero from the direction of the feed section 11 toward the extrusion section 12 , and the width of the outlet screw groove 134 gradually increases from zero toward the direction of the feed section 11 to the extrusion section 12 . The molten material can be reciprocated in the mixing section 13 to increase the mixing effect.

The inlet depth of the inlet screw groove 133 gradually decreases to zero from the direction of the feed section 11 toward the extrusion section 12 , and the depth of the outlet screw groove 134 gradually increases from zero toward the direction of the feed section 11 to the extrusion section 12 . The molten material that can make the molten material enter the mixing section 13 can cross the barrier flight 132 and the unmelted material is blocked by the barrier flight 132. Under the extensional flow and shear flow of the mixing section 13, the unfused solidified Glue or hard particles are dispersed, pushed by the main flight 131 to cross the barrier flight 132 and enter the extrusion section 12 .

Optionally, the height of the main flight 131 is 2mm-6mm higher than the height of the barrier flight 132. In this embodiment, the height of the main flight 131 is 4mm higher than that of the barrier flight 132, which can make the molten material easy After crossing the barrier flight 132 and the gel-like material is blocked by the barrier flight 132 , the gel-like material is dispersed under a strong tensile flow to pass the barrier flight 132 to improve the mixing and dispersing ability of the mixing section 13 .

As shown in Figure 4, the barrier screw rib 132 includes a first side slope 1321 and a second side slope 1322 extending along the helical direction, the top ends of the first side slope 1321 and the second side slope 1322 are close to each other and the bottom ends are away from each other, that is, , the first side bevel 1321 is located on the inner side of the spiral direction, the second bevel is located on the outside of the helix direction, the inclination angle of the first side bevel 1321 is greater than the inclination angle of the second side bevel 1322, it can be understood that the first side bevel 1321 is Facing the direction of the extrusion section 12, the second side slope 1322 is facing the direction of the feed section 11, and the dotted line box is a schematic cross-sectional view of the barrel 3 along the axial direction of the rod body 1. The inclination angle of the first side bevel 1321 is greater than the inclination angle of the second side bevel 1322, so that a wedge-shaped gap can be generated between the barrier flight 132 and the barrel 3, and the molten material flows from the feed section 11 to the extrusion section 12. When passing through the wedge-shaped gap, a velocity gradient will be generated, forming a strong extensional flow. Moreover, when the molten material passes through the wedge-shaped gap, it is also pushed by the helical barrier flight 132, so that the molten material is also subjected to shear force, and the molten material is subject to high-shear flow. Therefore, the dispersion and mixing of the gel and the further plasticizing and melting action can be realized to ensure that the material supplied to the extrusion section 12 is completely melted, and the quality of the molded foamed sheet after passing through the extrusion section 12 is ensured.

The pitch of the feeding section 11 is greater than that of the extrusion section 12, so that a compression ratio is generated in the barrel 3. The larger the compression ratio, the greater the extrusion ratio of the molten material, and the quality of the molded and foamed sheet will increase. the better.

Optionally, the helix angle of the main flight 131 is 14°-29° smaller than the helix angle of the barrier flight 132 , and the helix angle is the angle between the tangent of the helix of the flight and the cross-section of the rod body 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 can not only have a stronger tensile ability for the molten material, but also have a higher shear capacity.

Optionally, one end of the feeding section 11 on the rod body 1 is also provided with a connecting shaft 2, the connecting shaft 2 is coaxially connected with the rod body 1, the connecting shaft 2 is provided with a keyway 21, and the keyway 21 can be connected with the output end of the drive motor through a key. connected.

As shown in Figures 5 and 6, the main flight 131 also includes a third side bevel 1311 and a fourth side bevel 1312, the third side is located on the inside of the helical direction, the fourth side bevel 1312 is located on the outside of the helical direction, the third side The inclined surface 1311 is arranged perpendicular to the rod body 1, the connection between the third side inclined surface 1311 and the rod body 1 is rounded, the top of the fourth side inclined surface 1312 is close to the top of the third side inclined surface 1311, and the bottom end is away from the third side inclined surface 1311 The bottom end ensures that the main flight 131 has a high driving force towards the extruded section 12.

Optionally, the surface of the screw in this embodiment is provided with a nitride layer, the thickness of the nitride layer is 0.5mm-0.7mm, and the thickness of the nitride layer in this embodiment is preferably 0.6mm, which can effectively improve the wear resistance of the screw and durability.

Apparently, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, rather than limiting the implementation of the present invention. Various obvious changes, readjustments, and substitutions will occur to those skilled in the art without departing from the scope of the present invention. It is not necessary and impossible to exhaustively list all the implementation manners here. All modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (8)

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.

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