Single screw plastic extruder

Abstract

The present application provides a single screw plastic extruder, comprising a heating tube, a screw shaft arranged inside the heating tube and extending along the axis of the heating tube, an extrusion die comprising a die body, an outer die fixed to the end of the die body away from the heating tube in a detachable manner, a splitter plate arranged at the end of the outer die corresponding to the smaller end of the tapered inner cavity, an inner die extending into the outer die and connected to the splitter plate in a detachable manner, and an extrusion gap arranged between the outer wall of the inner die and the inner wall of the outer die. The die body is provided with a tapered inner cavity, thereby increasing the pressure of the molten granular material entering the die body, ensuring the plasticizing degree of the molten plastic particles, making the material more uniform, and the product shape more stable.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of plastic pipe production equipment, and particularly relates to a single-spiral plastic extruder. BACKGROUND

[0002] Plastic pipes are generally produced by extrusion molding, and plastic pipe molding is a very important step in the plastic pipe production process. The existing plastic pipe extrusion molding device sets a heating device in a heating pipe to completely melt plastic particles, and then extrudes the molten plastic particles through a shaft connecting spiral blades to the molten plastic in the cylinder, and the plastic is drawn out and cooled to form a plastic pipe.

[0003] The inner diameter and outer diameter of the plastic pipe are generally controlled by an extrusion die, and the existing extrusion die is generally changed by changing the plastic pipe traction speed or replacing the extrusion die, so that the inner diameter and outer diameter of the plastic pipe are adjusted with great difficulty. In addition, large-diameter plastic pipes are prone to insufficient plasticization of plastic particles during extrusion, which often causes large fluctuations in pipe size, thereby affecting production precision and quality.

[0004] Therefore, it is necessary to provide an improved technical solution for the above-mentioned deficiencies of the prior art. SUMMARY

[0005] The purpose of the present application is to overcome the deficiencies in the prior art, and the present application provides a single-spiral plastic extruder.

[0006] In order to achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0007] A single-spiral plastic extruder, comprising:

[0008] A heating pipe, one end of which is communicated with a feeding slot, and the other end of which is provided with an extrusion die;

[0009] A spiral shaft, which is arranged inside the heating pipe and extends along the axis of the heating pipe, and a spiral blade is arranged on the outer wall of the spiral shaft to drive the material in the feeding slot to the extrusion die;

[0010] The extrusion die comprises:

[0011] A die body, which is connected to the end of the heating pipe and has a conical inner cavity with a large end facing the heating pipe inside;

[0012] An outer die, which is fixed to the end of the die body away from the heating pipe in a detachable manner, and a flow dividing plate corresponding to the smaller end of the conical inner cavity is arranged at the end of the outer die;

[0013] An inner mold, which is connected to the flow distribution plate in a detachable manner after extending into the outer mold;

[0014] An extrusion gap is arranged between the outer wall of the inner mold and the inner wall of the outer mold.

[0015] Preferably, the inner mold comprises a variable-diameter section and a cylindrical section, the variable-diameter section is in the form of a frustum, and the smaller end of the variable-diameter section corresponds to the connection of the flow distribution plate.

[0016] The cylindrical section is located at the larger end of the variable-diameter section and is connected to the variable-diameter section through a smooth curve.

[0017] Preferably, there are multiple inner molds, and the outer diameters of the cylindrical sections of the multiple inner molds increase in turn.

[0018] Preferably, the variable-diameter section is close to the flow distribution plate and has a stud, the flow distribution plate has a threaded hole in the middle, and the end of the cylindrical section away from the flow distribution plate is provided with an inner hexagonal hole.

[0019] Preferably, the side of the flow distribution plate close to the variable-diameter section is provided with an arc-shaped ring groove, one side of the arc-shaped ring groove is connected to the variable-diameter section through a smooth curve, and the other side extends to the outer wall of the flow distribution plate to form an annular enlarged cavity on the side of the inner mold close to the flow distribution plate.

[0020] Preferably, the mold body is provided with a flange corresponding to the heating pipe, the end face of the mold body is provided with a mounting groove corresponding to the heating pipe, and the mounting groove is provided with a filter plate opposite to the heating pipe.

[0021] Preferably, the outer wall of the heating pipe is provided with multiple electric heating sheets.

[0022] The end of the heating pipe is provided with a connecting piece corresponding to the spiral shaft, one end of the connecting piece is connected to the spiral shaft in a detachable manner, and the other end is connected to the driving motor through a gearbox.

[0023] Preferably, the end of the spiral shaft corresponding to the connecting piece is provided with a polygonal prism, and the end of the connecting piece is provided with a corresponding insertion hole.

[0024] The end of the heating pipe is provided with a bearing seat corresponding to the middle of the connecting piece, and the heating pipe is fixed to the side wall of the bearing seat.

[0025] Preferably, the end of the connecting piece corresponding to the spiral shaft is provided with a circular baffle, and the outer diameter of the baffle is matched with the inner diameter of the heating pipe.

[0026] Preferably, the end of the spiral shaft corresponding to the mold body is provided with a conical head.

[0027] Beneficial effect: the die sets a conical inner cavity, thereby improving the pressure of the molten granular material into the die, ensuring the plasticizing degree of the molten plastic particles, making the material more uniform, and the product shape more stable.

[0028] The inner die can be replaced, thereby installing inner dies of different diameters, so as to replace the inner die according to pipes of different thicknesses and pipe diameters, facilitating adjustment of pipe specifications. BRIEF DESCRIPTION OF DRAWINGS

[0029] The drawings accompanying the specification of the present application provide further understanding of the present application, the illustrative embodiments thereof, and explanations for said application, and do not constitute an improper limitation of the present application. Among them:

[0030] Figure 1 A structure diagram of a plastic extruder in the specific embodiment provided by the present application;

[0031] Figure 2 A sectional view diagram of a plastic extruder in the specific embodiment provided by the present application;

[0032] Figure 3 A sectional view diagram of an extrusion die in the specific embodiment provided by the present application.

[0033] In the drawings: 1, heating pipe; 2, die body; 3, outer die; 4, inner die; 5, support; 6, feeding groove; 7, bearing seat; 8, gearbox; 9, driving motor; 10, screw shaft; 11, screw blade; 12, filter plate; 13, flow dividing plate; 14, annular enlarged cavity. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments in the present application belong to the scope of protection of the present application.

[0035] In the description of the present application, the orientations or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application, and do not require the present application to be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present application. The terms "connected", "connected" used in the present application should be understood broadly, for example, can be fixed connection, can also be detachable connection; can be directly connected, can also be indirectly connected through intermediate components. For those skilled in the art, the specific meanings of the above terms can be understood according to the specific circumstances.

[0036] The present application will be described in detail below with reference to the drawings and in conjunction with embodiments. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0037] As shown in the structural diagram of the plastic extruder, the plastic extruder comprises a heating pipe 1, a spiral shaft 10 and an extrusion die. The heating pipe 1 is a circular pipe body. A feeding groove 6 is connected to one end of the heating pipe 1, and an extrusion die is arranged at the other end. The spiral shaft 10 is arranged inside the heating pipe 1. The spiral shaft 10 guides the material from the feeding groove 6 to the extrusion die. The extrusion die extrudes the molten plastic to form a pipe. The spiral shaft 10 is correspondingly connected to a gearbox 8 and a driving motor 9 to provide power for the driving of the material. During the transmission of the material, the heating pipe 1 heats the internal material, so that the material becomes molten and reaches the extrusion die. Figure 1 As shown in the sectional view of the plastic extruder, the outer wall of the spiral shaft 10 is provided with spiral blades 11 to drive the material in the feeding groove 6 to the extrusion die through the spiral blades 11. The die body 2 is in the shape of a truncated cone as a whole. The die body 2 is provided with a flange corresponding to the heating pipe 1. The flange is butted to the end of the heating pipe 1. One end of the connecting piece corresponding to the spiral shaft 10 is inserted into the insertion hole at the end of the connecting piece. The end of the heating pipe 1 is provided with a bearing seat 7 corresponding to the middle part of the connecting piece. The heating pipe 1 is fixed to the side wall of the bearing seat 7. One end of the connecting piece corresponding to the spiral shaft 10 is provided with a circular baffle. The outer diameter of the baffle is matched with the inner diameter of the heating pipe 1 to block the movement of the material away from the end of the extrusion die.

[0038] Figure 2 As shown in the sectional view of the extrusion die, the extrusion die comprises a die body 2, an outer die 3 and an inner die 4. The die body 2 is connected to the end of the heating pipe 1 and has a tapered inner cavity with a large end facing the heating pipe 1. In this way, the pressure of the molten material is increased after the molten material is transmitted to the extrusion die, thereby increasing the pressure of the molten granular material into the die body 2, ensuring the plasticizing degree of the molten plastic particles, and making the material more uniform. The outer die 3 and the inner die 4 are fixed by a detachable manner. The extrusion gap is arranged between the outer wall of the inner die 4 and the inner wall of the outer die 3. In this way, the inner die 4 can be replaced according to the actual situation, so that inner dies 4 with different diameters are installed. The inner die 4 is replaced according to the pipe with different thickness and pipe diameter, which is convenient for adjusting the pipe specifications and avoids the uneven pipe quality caused by the conventional traction speed adjustment.

[0039] As shown in the sectional view of the extrusion die, the extrusion die comprises a die body 2, an outer die 3 and an inner die 4. The die body 2 is connected to the end of the heating pipe 1 and has a tapered inner cavity with a large end facing the heating pipe 1. In this way, the pressure of the molten material is increased after the molten material is transmitted to the extrusion die, thereby increasing the pressure of the molten granular material into the die body 2, ensuring the plasticizing degree of the molten plastic particles, and making the material more uniform. The outer die 3 and the inner die 4 are fixed by a detachable manner. The extrusion gap is arranged between the outer wall of the inner die 4 and the inner wall of the outer die 3. In this way, the inner die 4 can be replaced according to the actual situation, so that inner dies 4 with different diameters are installed. The inner die 4 is replaced according to the pipe with different thickness and pipe diameter, which is convenient for adjusting the pipe specifications and avoids the uneven pipe quality caused by the conventional traction speed adjustment. Figure 3 As shown in the sectional view of the extrusion die, the extrusion die comprises a die body 2, an outer die 3 and an inner die 4. The die body 2 is connected to the end of the heating pipe 1 and has a tapered inner cavity with a large end facing the heating pipe 1. In this way, the pressure of the molten material is increased after the molten material is transmitted to the extrusion die, thereby increasing the pressure of the molten granular material into the die body 2, ensuring the plasticizing degree of the molten plastic particles, and making the material more uniform. The outer die 3 and the inner die 4 are fixed by a detachable manner. The extrusion gap is arranged between the outer wall of the inner die 4 and the inner wall of the outer die 3. In this way, the inner die 4 can be replaced according to the actual situation, so that inner dies 4 with different diameters are installed. The inner die 4 is replaced according to the pipe with different thickness and pipe diameter, which is convenient for adjusting the pipe specifications and avoids the uneven pipe quality caused by the conventional traction speed adjustment.

[0040] ​In an optional embodiment, the single-screw plastic extruder comprises a heating tube 1, a screw shaft 10 and an extrusion die, one end of the heating tube 1 is provided with a feeding port arranged on the upper side of the heating tube 1, the feeding port is communicated with a feeding groove 6, and the granular material to be melted is guided into the heating tube 1 from the feeding groove 6; the heating tube 1 has a heating element to heat the material inside; the other end of the heating tube 1 is provided with the extrusion die; the screw shaft 10 is arranged inside the heating tube 1 and extends along the axis of the heating tube 1; the outer wall of the screw shaft 10 is provided with screw blades 11 to drive the material in the feeding groove 6 to the extrusion die; and the material is heated and melted in the process of being transmitted from the feeding port to the extrusion die.

[0041] The extrusion die comprises a die body 2, an outer die 3 and an inner die 4; the die body 2 is detachably connected to the end of the heating tube 1 and has a tapered inner cavity with a large end facing the heating tube 1 inside; or the die body 2 is a cast part and is cast as a frustoconical shell; the outer die 3 is detachably fixed to the end of the die body 2 away from the heating tube 1, for example, flange connection or threaded connection; the end of the outer die 3 is provided with a flow distribution plate 13 corresponding to the smaller end of the tapered inner cavity; the flow distribution plate 13 comprises a plurality of flow distribution holes uniformly distributed about the circumference thereof; and the flow distribution plate 13 distributes the material extruded to the extrusion die, so that the material can be uniformly extruded in the circumferential direction and the uniformity of the pipe wall thickness is ensured.

[0042] The inner die 4 extends into the outer die 3 and is detachably connected to the flow distribution plate 13; an extrusion gap is arranged between the outer wall of the inner die 4 and the inner wall of the outer die 3; the extrusion gap is annular; the material extruded through the gap is cylindrical; and the material is shaped through heating and sizing processes, so as to form a pipe.

[0043] In another optional embodiment, the inner die 4 comprises a variable-diameter section and a cylindrical section; the variable-diameter section is a frustoconical structure; the smaller end of the variable-diameter section corresponds to the connection of the flow distribution plate 13; the variable-diameter section makes the material transition to the extrusion gap, further increases the pressure, and ensures the molding of the pipe; and the cylindrical section is located at the larger end of the variable-diameter section and is connected to the variable-diameter section through a smooth curved surface; the smooth curved surface makes the material flow more smoothly inside the extrusion die, improving the molding quality.

[0044] In this embodiment, there are multiple inner dies 4, and the multiple inner dies 4 are of multiple specifications; specifically, the outer diameters of the cylindrical sections of the multiple inner dies 4 increase successively; thus, the specifications of the inner dies 4 can be selected according to the requirements of the wall thickness or the diameter of the pipe, facilitating the adjustment of the specifications of the pipe.

[0045] In this embodiment, the variable-diameter section is provided with a threaded stud close to the flow distribution plate 13; the middle of the flow distribution plate 13 is provided with a threaded hole; the stability of the inner die 4 is ensured through threaded connection; and the cylindrical section is provided with an inner hexagonal hole at the end away from the flow distribution plate 13, facilitating disassembly and replacement.

[0046] In the embodiment, the outer mold 3 can also have multiple specifications, and the inner diameters of the outer molds 3 of different specifications gradually increase. In addition, the detachability of the outer mold 3 can reduce the production difficulty of the mold body 2 and reduce the quality cost.

[0047] In another optional embodiment, the arc-shaped ring groove is arranged on one side of the flow distribution plate 13 close to the variable-diameter section. The ring groove releases the pressure of the material after the first pressurization, and then performs the second pressurization through a more narrow extrusion gap. The second pressurization can further ensure the plasticizing degree of the molten plastic particles, so that the material is more uniform, and the product shape is more stable.

[0048] One side of the arc-shaped ring groove is connected to the variable-diameter section through a smooth curved surface, so as to ensure the smooth flow of the material. The other side extends to the outer wall of the flow distribution plate 13. Specifically, the extension position of the other side corresponds to the radius of the arc-shaped groove, so as to form an annular enlarged cavity 14 on the side of the inner mold 4 close to the flow distribution plate 13.

[0049] In the embodiment, the flow distribution holes are 8-12, and are opposite to the annular enlarged cavity 14.

[0050] In another optional embodiment, the mold body 2 is provided with a flange corresponding to the heating pipe 1. The end surface of the mold body 2 is provided with a mounting groove corresponding to the heating pipe 1. The mounting groove is provided with a filter plate 12 opposite to the heating pipe 1. The filter plate 12 filters the material flowing into the extrusion die. The filter plate 12 can be fixed in the mounting groove by screws.

[0051] In another optional embodiment, the outer wall of the heating pipe 1 is provided with a plurality of electric heating sheets in the form of a ring. The plurality of electric heating sheets are distributed in the axial direction of the heating pipe 1 in a spaced or parallel manner, so as to heat the material.

[0052] In the embodiment, a temperature monitoring meter is arranged in the inner cavity of the mold body 2. The temperature monitoring meter is connected to a control circuit, so as to control the electric heating sheets and ensure that the internal material temperature is appropriate.

[0053] The end of the heating pipe 1 is provided with a connecting piece corresponding to the spiral shaft 10. One end of the connecting piece is connected to the spiral shaft 10 in a detachable manner. The other end is connected to the driving motor 9 through the gearbox 8. In this way, the assembly difficulty of the spiral shaft 10 is reduced, and the spiral shaft 10 is convenient to disassemble and overhaul.

[0054] In the embodiment, one end of the connecting piece corresponding to the spiral shaft 10 is provided with a polygonal prism. The end of the connecting piece is provided with a corresponding insertion hole of the polygonal prism. The polygonal prism ensures that the torque is transmitted to the spiral shaft 10. The spiral blade 11 on the outer wall of the spiral shaft 10 is matched with the inner diameter of the heating pipe 1.

[0055] The end of the heating pipe 1 is provided with a bearing seat 7 corresponding to the middle part of the connecting piece, the end of the heating pipe 1 is provided with a flange, and the flange is fixed to the side wall of the bearing seat 7, and at least one bearing is arranged in the bearing seat 7, and the connecting piece is rotationally connected to the connecting piece.

[0056] In the embodiment, the end of the connecting piece corresponding to the spiral shaft 10 is provided with a circular baffle, the outer diameter of the baffle is matched with the inner diameter of the heating pipe 1, and the connecting piece extends to the side of the feeding port away from the extrusion die, the baffle is a blocking material movement route, so that the material cannot move to the side away from the extrusion die.

[0057] The end of the spiral shaft corresponding to the die body 2 is provided with a conical head, so that the material in the heating pipe 1 can flow smoothly, a plurality of supports 5 are arranged below the heating pipe 1 to support the heating pipe 1 to extend in the horizontal direction, a gap corresponding to the outer diameter of the heating pipe 1 is arranged above the support 5, and the heating pipe 1 is fixed by welding, pressing and the like.

[0058] The heating pipe 1 can be made of cast iron process, and can quickly conduct the heat of the electric heating sheet.

[0059] The above only describes the preferred embodiment of the present application, and does not limit the present application, any modification, equivalent replacement, improvement and the like within the spirit and principle of the present application are within the protection scope of the claims of the present application.

Claims

1. A single screw plastic extruder characterized by, The utility model relates to a kind of extrusion molding machine, including: Heating pipe, one end of the heating pipe is communicated into feed tank, and the other end is equipped with extrusion die; Spiral shaft, the spiral shaft is arranged inside the heating pipe, and extends along the axis of the heating pipe, and spiral blade is arranged on the outer wall of the spiral shaft to drive the material in the feed tank to the extrusion die; The extrusion die includes: Die body, the die body is connected at the end of the heating pipe, and the inside of the die body has a tapered inner cavity with a large end facing the heating pipe; Outer die, the outer die is fixed on the end of the die body away from the heating pipe in a detachable manner, and a flow divider corresponding to the smaller end of the tapered inner cavity is arranged at the end of the outer die; Inner die, the inner die extends into the outer die and is detachably connected to the flow divider; An extrusion gap is arranged between the outer wall of the inner die and the inner wall of the outer die;The inner die includes a variable-diameter section and a cylindrical section, the variable-diameter section is a frustum structure, and the smaller end of the variable-diameter section corresponds to the flow divider; The cylindrical section is located at the larger end of the variable-diameter section and is connected to the variable-diameter section through a smooth curved surface; The side of the flow divider close to the variable-diameter section is provided with an arc ring groove, one side of the arc ring groove is connected to the variable-diameter section through a smooth curved surface, and the other side extends to the outer wall of the flow divider to form an annular enlarged cavity on the side of the inner die close to the flow divider; The end of the heating pipe is provided with a connector corresponding to the spiral shaft, one end of the connector is detachably connected to the spiral shaft, and the other end is connected to the driving motor through a gearbox; The end of the connector corresponding to the spiral shaft is provided with a polygonal prism, and the end of the connector is provided with a corresponding insertion hole for the polygonal prism; A bearing seat corresponding to the middle part of the connector is arranged at the end of the heating pipe, and the heating pipe is fixed to the side wall of the bearing seat; The end of the connector corresponding to the spiral shaft is provided with a circular baffle, and the outer diameter of the baffle is matched with the inner diameter of the heating pipe.

2. Single-screw plastic extruder according to claim 1, characterized in that The inner die has multiple cylindrical sections with increasing outer diameters.

3. Single screw plastic extruder according to claim 1, characterized in that The variable-diameter section close to the flow divider has a stud, and the middle part of the flow divider has a threaded hole; The end of the cylindrical section away from the flow divider is provided with an internal hexagonal hole.

4. Single screw plastic extruder according to claim 1, characterized in that The die body is provided with a flange corresponding to the heating pipe, the end surface of the die body is provided with a mounting groove corresponding to the heating pipe, and a filter plate opposite to the heating pipe is arranged in the mounting groove.

5. The single-screw plastic extruder of claim 1, wherein The outer wall of the heating pipe is provided with multiple electric heating sheets.

6. The single-screw plastic extruder of claim 1, wherein The end of the spiral shaft corresponding to the die body is provided with a tapered head.

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