Pressure-equalizing extrusion die head

Abstract

The utility model relates to the technical field of PVC (polyvinyl chloride) pipe extrusion dies, and discloses a pressure equalizing type extrusion die head which comprises a die shell formed by mounting two half shells, a mouth die is arranged in the die shell, a core rod is coaxially arranged in the mouth die, a gap between the mouth die and the core rod forms a blank forming area, and a flow dividing head is coaxially arranged at the position, facing a feeding port, of the core rod. The diameter of the flow dividing head is gradually reduced in the direction towards the feeding port, a gap between the flow dividing head and the mold shell forms a compression area, and a plurality of flow deflectors are distributed on the flow dividing head in the circumferential direction. The extrusion die head has the effect that the discharging uniformity degree of the extrusion die head is improved.

Description

Technical Field

[0001] The present application relates to the technical field of PVC pipe extrusion dies, and in particular to an isostatic extrusion die head. Background Art

[0002] PVC plastic is a widely used plastic material with the advantages of good chemical corrosion resistance, electrical insulation, mechanical strength, processing performance and low cost. Therefore, it has been widely used in construction, wire and cable, packaging, medical equipment, automotive parts and other fields.

[0003] Extrusion molding is generally used for the production of continuous profiles such as thermoplastic pipes, rods, films, wires, etc. The product molding process is completed in two stations, the shaping and the shaping. Therefore, the extrusion molding die includes two parts: the shaping die and the shaping die. The shaping part is connected to the extruder and is commonly known as the die head.

[0004] The die head design in the prior art greatly affects the final extrusion speed and uniformity of the molten plastic liquid. The plastic melt rushing in from the feeding direction of the ordinary die head is easy to hit the core rod and generate pressure accumulation, which in turn causes the die head to extrude unevenly, resulting in uneven thickness of the product finally extruded from the die head, and even fracture.

[0005] A Chinese patent with announcement number CN212372662U discloses an improved extrusion die head for PE pipes, including a transmission shaft and a pad. A pad is provided at the right end of the transmission shaft, and the transmission shaft and the pad are fixed by spot welding. An extrusion head is provided at the right end of the pad, and a sleeve is provided around the outer side of the extrusion head, and the sleeve is fixed to the extrusion head by sleeve connection.

[0006] During the operation of the above-mentioned extrusion die head, when the die head is in use, the impact force of the plastic melt hitting the core rod in the die head can be reduced by setting a buffer. However, after the plastic melt enters the die head, the irregular shaking of the die head caused by the buffer will interfere with the uniformity of the flow rate of the plastic melt in the die head, making it difficult to ensure that the molding blanks extruded through the extrusion die head can maintain continuous and uniform discharge, which greatly reduces the qualification degree of the molding blanks. Utility Model Content

[0007] In order to improve the uniformity of material discharge from an extrusion die head, the present application provides a pressure-equalizing extrusion die head.

[0008] The present application provides a pressure-equalizing extrusion die head adopts the following technical solution:

[0009] A pressure-equalizing extrusion die head comprises a mold shell formed by installing two half shells, a mouth die is arranged in the mold shell, a core rod is coaxially arranged in the mouth die, a gap between the mouth die and the core rod forms a forming area of ​​the blank, a diverter head is coaxially arranged on the core rod toward a feed inlet, and the diameter of the diverter head gradually decreases in the direction toward the feed inlet, a compression area is formed between the gap between the diverter head and the mold shell, and a plurality of guide vanes are distributed circumferentially on the diverter head.

[0010] By adopting the above technical solution, the extrusion die head is installed at the spiral discharge port of the extruder, and the plastic melt flows through the compression zone and the molding zone from the feed port of the mold shell in sequence, and the final molded blank is extruded from the discharge port of the extrusion die head. When the plastic melt enters the mold shell from the feed port, the plastic melt hits the diverter head and several guide plates. At this time, the pressure generated by the plastic melt hitting the diverter head is evenly dispersed by the several guide plates on the diverter head, eliminating the uneven extrusion phenomenon caused by pressure accumulation when feeding the mold, simplifying the adjustment time spent for uniform extrusion during the production process, thereby improving the production efficiency of the extrusion mold in producing PVC pipes.

[0011] Optionally, several of the guide plates are perpendicular to the axis of the diverter head, and the ends away from the diverter head abut against the inner wall of the mold shell, and the ends of the guide plates abutting against the inner wall of the mold shell are provided with connecting plates for connecting to the inner wall of the mold shell, and the mold shell is provided with fixings for fixing the connecting plates.

[0012] By adopting the above technical scheme, the guide plate not only has the effect of evenly dispersing the pressure in the mold shell, but also plays a role in connecting and fixing the connection between the supporting core rod and the mold shell. The setting of the connecting plate increases the contact area with the inner wall of the mold shell, facilitates the connection between the mold shell and the connecting plate by the fixing parts, and improves the stability of the extrusion mold during use.

[0013] Optionally, the mouth die is detachably connected to the mold shell, and the mouth die includes a speed control module for controlling the volume of the compression zone and a diameter control module for controlling the outer diameter of the molded PVC pipe. The connection between the speed control module and the diameter control module has a smooth transition, and a positioning rod is commonly provided between the speed control module and the diameter control module.

[0014] By adopting the above technical scheme, the diameter control module can be replaced before the extrusion die is used according to the specification requirements of the outer diameter of the required PVC pipe; at the same time, according to the discharge speed of the extruder, speed control modules with different inclination degrees can be installed before the extrusion die is used to achieve the purpose of controlling the flow rate of the plastic melt, which not only improves the application range of the extrusion die, but also facilitates the replacement of the die when it is damaged, thereby improving the service life of the extrusion die.

[0015] Optionally, an alignment hole is provided between the mold shell and the diameter control module, and a plug-in rod is slidably penetrated through the alignment holes of the mold shell and the diameter control module.

[0016] By adopting the above technical solution, when installing the extrusion die, the connecting rod is first inserted into the alignment holes of the mold shell and the diameter control module, which helps to achieve a quick installation effect between the auxiliary mold shell and the diameter control module.

[0017] Optionally, the plug-in rod includes a polished rod, a screw rod coaxially arranged at the bottom end of the polished rod, and an end block arranged at the top end of the polished rod, wherein the inner circle of the alignment hole on the diameter control module is provided with a thread matching the screw rod, and when the screw rod is connected to the diameter control module through a thread, the end block abuts against the outer wall of the mold shell.

[0018] By adopting the above technical solution, when the plug-in rod is connected to the diameter control module through threads and the end block abuts against the outer wall of the mold shell, the connection strength between the mold shell and the diameter control module is further enhanced, thereby improving the stability of the extrusion mold during use.

[0019] Optionally, a sealing ring is provided at the connection point on the mold shell.

[0020] By adopting the above technical solution, the provision of the sealing ring improves the sealing performance of the extrusion die after installation and improves the stability of the extrusion die during use.

[0021] Optionally, a cooling ring is provided at the discharge port of the die.

[0022] By adopting the above technical solution, a cooling ring is set at the discharge port of the die, which can improve the molding completeness of the molded tube extruded through the die head, thereby reducing the liquid shapelessness of the molten material when it is extruded from the die head, and improving the extrusion effect of the die head.

[0023] Optionally, a filter plate is provided on the mold shell at the feed inlet.

[0024] By adopting the above technical solution, a filter plate is arranged at the feed inlet to reduce the amount of impurity particles in the molten material entering the molding cavity, thereby improving the molding effect of the molding tube extruded through the die head.

[0025] In summary, the present application includes at least one of the following beneficial technical effects:

[0026] 1. Install the extrusion die head at the spiral outlet of the extruder. The plastic melt flows through the compression zone and the molding zone from the feed port of the mold shell in sequence. The final molded blank is extruded from the outlet of the extrusion die head. When the plastic melt enters the mold shell from the feed port, it hits the diverter head and several guide vanes. At this time, the pressure generated by the plastic melt hitting the diverter head is evenly dispersed by the several guide vanes on the diverter head, eliminating the uneven extrusion caused by pressure accumulation during mold feeding, simplifying the adjustment time spent on uniform extrusion during the production process, thereby improving the production efficiency of PVC pipes produced by the extrusion die;

[0027] 2. The guide plate not only has the effect of evenly dispersing the pressure in the mold shell, but also plays a role in connecting and fixing the connection between the supporting core rod and the mold shell. The setting of the connecting plate increases the contact area with the inner wall of the mold shell, which facilitates the connection between the mold shell and the connecting plate by the fixing part, and improves the stability of the extrusion mold during use;

[0028] 3. The diameter control module can be replaced before the extrusion die is used according to the specifications of the required outer diameter of the PVC pipe; at the same time, according to the discharge speed of the extruder, speed control modules with different inclinations can be installed before the extrusion die is used to control the flow rate of the plastic melt, which not only improves the application range of the extrusion die, but also facilitates the replacement of the die when it is damaged, thereby increasing the service life of the extrusion die. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present application.

[0030] Figure 2 It is a side view of the overall structure of one side of the filter plate in the embodiment of the present application.

[0031] Figure 3 yes Figure 2 Cross-sectional view at AA in the middle.

[0032] Figure 4 yes Figure 2 Cross-sectional view at the middle BB.

[0033] Description of reference numerals:

[0034] 1. mold shell; 11. sealing strip; 12. alignment hole; 13. plug-in rod; 131. polished rod; 132. screw rod; 133. end block; 2. filter plate; 3. diverter; 31. guide plate; 311. connecting plate; 32. fixing part; 4. compression zone; 5. core rod; 6. die; 61. speed control module; 62. diameter control module; 63. positioning rod; 7. molding zone; 8. sealing cover; 9. cooling ring. DETAILED DESCRIPTION

[0035] The following is combined with Figure 1-4 This application is described in further detail.

[0036] The embodiment of the present application discloses a pressure-equalizing extrusion die head.

[0037] Reference Figures 1 to 4 A pressure-equalizing extrusion die head includes a mold shell 1, which is composed of two open and opposite square half shells connected and installed by bolts and connecting ears, and a sealing strip 11 is fixedly arranged on the connecting side wall of the mold shell 1. A filter plate 2 is fixedly arranged at the feed port on the side wall of the mold shell 1, a diverter head 3 is arranged near the feed port in the mold shell 1, and the gap between the diverter head 3 and the mold shell 1 forms a compression zone 4, a core rod 5 is coaxially arranged at the diverter head 3 away from the feed port in the mold shell 1, and the core rod 5 and the diverter head 3 are connected together by bolts, a mouth die 6 is arranged between the core rod 5 and the mold shell 1, the mouth die 6 is installed in the mold shell 1, and the gap between the mouth die 6 and the core rod 5 forms a forming area 7 of the blank, and a plugging cover 8 is installed on one side of the mold shell 1 near the discharge port of the forming area 7 by bolts, and a cooling ring 9 is sleeved on the outer wall of the mouth die 6 extending from the plugging cover 8, and the cooling ring 9 is located at the discharge port of the mouth die 6.

[0038] Reference Figures 1 to 4 The extrusion die is installed at the spiral discharge port of the extruder. The plastic melt enters the filter plate 2 from the feed port of the mold shell 1 to filter the impurities, and then flows through the compression area 4 and the molding area 7 in sequence. Under the cooling of the cooling ring 9, the final molded blank is extruded from the discharge port of the extrusion die.

[0039] Reference Figure 3 and Figure 4 , the diameter of the diverter head 3 gradually decreases in the direction toward the feed port, and a plurality of guide vanes 31 are distributed circumferentially on the diverter head 3, and the plurality of guide vanes 31 are perpendicular to the axis of the diverter head 3. In this embodiment, six guide vanes 31 are taken as an example, and one end of the six guide vanes 31 is integrally formed on the diverter head 3, and the other end abuts against the inner wall of the mold shell 1, wherein two guide vanes 31 symmetrical along the axis of the diverter head 3 are fixedly provided with connecting plates 311 at the opposite ends, and the mold shell 1 is provided with fixing parts 32, and in this embodiment, the fixing parts 32 are two groups of bolts, each group of three bolts, and the bolts are inserted from the outer wall of the mold shell 1 through threads, and penetrate the mold shell 1 and the connecting plate 311 together.

[0040] Reference Figure 3The die 6 includes a speed control module 61 and a diameter control module 62, and the connection between the speed control module 61 and the diameter control module 62 is smoothly transitioned. The speed control module 61 is located between the diverter head 3 and the mold shell 1, and the aperture of the compression zone 4 between the speed control module 61 and the diverter head 3 gradually decreases along the feeding direction. The inclined angle between the inner wall of the speed control module 61 and the axis of the diverter head 3 affects the flow rate of the plastic melt in the compression zone 4. By replacing different speed control modules 61, the effect of uniform speed extrusion can be achieved as needed. A positioning rod 63 is provided between the speed control module 61 and the diameter control module 62.

[0041] Reference Figure 4 In order to improve the rapid installation between the mouth die 6 and the mold shell 1, an alignment hole 12 is provided between the mold shell 1 and the diameter control module 62, and a plug-in rod 13 is slidably penetrated through the alignment hole 12 of the mold shell 1 and the diameter control module 62. The plug-in rod 13 includes a polished rod 131, a screw rod 132 and an end block 133, wherein the screw rod 132 is coaxially integrally formed at the bottom end of the polished rod 131, and the end block 133 is integrally formed at the top end of the polished rod 131, wherein the inner circle of the alignment hole 12 on the diameter control module 62 is provided with a thread, and when the screw rod 132 is connected to the diameter control module 62 by threading, the end block 133 abuts against the outer wall of the mold shell 1.

[0042] The implementation principle of a pressure-equalizing extrusion die head in the embodiment of the present application is as follows: the extrusion die head is installed at the spiral discharge port of the extruder, and the plastic melt enters the filter plate 2 from the feed port of the mold shell 1 to filter the impurities, and then flows through the compression zone 4 and the molding zone 7 in sequence, wherein when the plastic melt enters the compression zone 4 in the mold shell 1 from the feed port, the plastic melt hits the diverter head 3 and several guide plates 31, and the pressure generated by the plastic melt hitting the diverter head 3 is evenly dispersed by several guide plates 31 on the diverter head 3, eliminating the uneven extrusion phenomenon caused by pressure accumulation when the mold is fed. And under the cooling of the cooling ring 9, the molded material embryo is extruded from the discharge port of the extrusion die head.

[0043] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A pressure-equalizing extrusion die head, characterized in that: The mold shell (1) comprises two half shells installed, a mouth die (6) is arranged in the mold shell (1), a core rod (5) is coaxially arranged in the mouth die (6), a gap between the mouth die (6) and the core rod (5) forms a forming area (7) for the blank, a diverter head (3) is coaxially arranged on the core rod (5) towards the feed inlet, and the diameter of the diverter head (3) gradually decreases in the direction towards the feed inlet, a compression area (4) is formed between the diverter head (3) and the mold shell (1), and a plurality of guide vanes (31) are distributed circumferentially on the diverter head (3).

2. A pressure-equalizing extrusion die according to claim 1, characterized in that: The guide plates (31) are all perpendicular to the axis of the diverter head (3), and the ends away from the diverter head (3) abut against the inner wall of the mold shell (1), and the ends of the guide plates (31) abutting against the inner wall of the mold shell (1) are provided with connecting plates (311) for connecting to the inner wall of the mold shell (1), and the mold shell (1) is provided with fixing parts (32) for fixing the connecting plates (311).

3. A pressure-equalizing extrusion die according to claim 1, characterized in that: The die (6) is detachably connected to the mold shell (1), and the die (6) comprises a speed control module (61) for controlling the volume of the compression zone (4) and a diameter control module (62) for controlling the outer diameter of the molded PVC pipe. The connection between the speed control module (61) and the diameter control module (62) is smoothly transitioned, and a positioning rod (63) is provided between the speed control module (61) and the diameter control module (62).

4. A pressure-equalizing extrusion die according to claim 3, characterized in that: An alignment hole (12) is provided between the mold shell (1) and the diameter control module (62), and a plug-in rod (13) is slidably inserted through the alignment holes (12) of the mold shell (1) and the diameter control module (62).

5. A pressure-equalizing extrusion die head according to claim 4, characterized in that: The plug-in rod (13) comprises a smooth rod (131), a screw rod (132) coaxially arranged at the bottom end of the smooth rod (131), and an end block (133) arranged at the top end of the smooth rod (131), wherein a thread matching the screw rod (132) is provided on the inner circle of the alignment hole (12) on the diameter control module (62), and when the screw rod (132) is connected to the diameter control module (62) by threading, the end block (133) abuts against the outer wall of the mold shell (1).

6. A pressure-equalizing extrusion die head according to claim 1, characterized in that: A sealing strip (11) is provided at the connection point on the mold shell (1).

7. A pressure-equalizing extrusion die head according to claim 1, characterized in that: A cooling ring (9) is sleeved at the discharge port of the die (6).

8. A pressure-equalizing extrusion die head according to claim 1, characterized in that: A filter plate (2) is provided on the mold shell (1) at the feed inlet.

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