A continuous push forming device for four-fluorine corrugated pipe

Abstract

The utility model provides a kind of continuous push forming device of four fluorine bellows, including extrusion mechanism and forming mechanism, and the barrel of forming mechanism is equipped with split mould, and each mould segment is realized synchronous opening and closing by push rod connecting hydraulic cylinder, and adjacent mould segment is connected by dovetail groove radial sliding connection.The barrel is equipped with three independent temperature control heating jacket, and the gradient temperature requirement of matching material plasticizing, forming and shaping is matched;The built-in inner cooling channel of core rod is connected with circulating cold source, to realize rapid cooling and shaping.The hydraulic cylinder piston end is configured with two-way damper to eliminate vibration, and the heating jacket is disassembled and moved by sliding groove and locking bolt.The utility model forms fluorine plastic four fluorine bellows by split mould dynamic forming and temperature subsection control stable forming, and solves the problem that traditional push method cannot continuously form four fluorine bellows.

Description

Technical Field

[0001] This utility model relates to the technical field of PTFE corrugated pipe processing equipment, specifically to a continuous extrusion forming device for PTFE corrugated pipes. Background Technology

[0002] Fluoroplastic corrugated pipes are widely used in industrial production due to their excellent corrosion resistance and flexibility. The molding processes for fluoroplastic pipes include extrusion molding and isobaric molding. Extrusion molding uses mechanical force to force a polytetrafluoroethylene (PTFE) paste through a die in a plunger extruder to form a tube. Isobaric molding, on the other hand, involves filling PTFE powder into an elastic mold and then uniformly compressing the powder into a tube within a high-pressure container using liquid or gas pressure. Extrusion molding is low-cost and highly continuous; however, for PTFE corrugated pipe structures, traditional integral molds cannot achieve continuous molding of the corrugated structure. Isobaric molding is often used to form PTFE corrugated pipes of a certain length, which are then welded together, resulting in lengthy processing steps and low processing efficiency. Utility Model Content

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a continuous push-forming device for PTFE corrugated pipes, so as to realize the continuous push-forming of PTFE corrugated pipes.

[0004] To achieve the above objectives, the technical solution provided by this utility model is as follows:

[0005] A continuous extrusion molding apparatus for PTFE corrugated pipes includes an extrusion mechanism and a molding mechanism connected in sequence. The molding mechanism includes a cylinder with a mandrel inside. One end of the mandrel is connected to the connection between the extrusion mechanism and the molding mechanism. The side wall of the cylinder is provided with segmented molds arranged in a circumferential array. Each segmented mold has a push rod connected radially to its outer side. The push rod passes through the cylinder and is connected to a power device. Adjacent segmented molds are joined together in a radially arranged stepped configuration to form a closed mold cavity.

[0006] The extrusion and molding mechanisms form the basic equipment for continuous molding. The cylinder serves as the main support of the molding mechanism, and the mandrel positions the material flow path to ensure consistent pipe inner diameter. The segmented mold is connected to a hydraulic power unit via push rods to achieve synchronous opening and closing. The assembled closed mold cavity ensures sealing when the mold is closed, preventing material leakage. The periodic closing and opening of the segmented mold, driven by hydraulic pressure, creates a corrugated structure for continuous pressing molding, directly solving the core problem of traditional integral molds' inability to achieve continuous molding.

[0007] Furthermore, the stepped splicing assembly is a dovetail groove, and each segment of the mold has an anti-overflow flange on its side. The dovetail groove enables radial sliding guidance between the mold segments, improving splicing accuracy and ensuring the geometric stability of the closed mold cavity. The anti-overflow flange further prevents material from overflowing in the mold opening and closing gap, avoiding flash defects.

[0008] Furthermore, the power unit includes a hydraulic cylinder, the piston end of which is connected to the push rod. The hydraulic cylinder provides high thrust and stable power output, ensuring the synchronous opening and closing of the segmented mold.

[0009] Furthermore, the dovetail groove of the stepped splicing assembly is embedded with an elastic sealing strip.

[0010] Furthermore, the extrusion mechanism and the molding mechanism are connected by a flange, and the mating surface of the flange is provided with an annular positioning boss.

[0011] Furthermore, the segmented mold consists of 6-8 segments, each distributed at an equal angle along the circumference of the cylinder. The number of segments balances the structural strength and flexibility of the mold, avoiding the complexity of control due to too many segments or the uneven molding due to too few segments.

[0012] Furthermore, the mandrel is equipped with an internal cooling channel, which is connected to a circulating cold source via pipeline. This ensures that the PTFE corrugated pipe quickly sets during dynamic molding, maintaining a continuous production rhythm.

[0013] Furthermore, a heating jacket is fitted onto the outer wall of the cylinder, and three sets of independently temperature-controlled resistance wire modules are embedded within the heating jacket, corresponding to the front, middle, and rear sections of the cylinder, respectively; the resistance wire modules are electrically connected to an external temperature control system. The independent temperature control modules adapt to the material phase change requirements, preventing temperature fluctuations from affecting the molding quality.

[0014] Furthermore, a bidirectional damper is fitted onto the piston end of the hydraulic cylinder, and the bidirectional damper is embedded in the lug structure outside the cylinder body. The bidirectional damper absorbs the impact vibration of the hydraulic cylinder's movement, ensuring smooth mold opening and closing and reducing mechanical wear.

[0015] Furthermore, the heating jacket and the cylinder are slidably connected via an axial groove and a slider, and the groove and slider are fastened together by locking bolts radially arranged on the cylinder. The groove and locking bolts allow for axial position adjustment of the heating jacket to adapt to the temperature control requirements of different pipe materials.

[0016] The advantages and beneficial effects of this utility model are as follows:

[0017] 1. The circumferential array design of the segmented mold, combined with hydraulic synchronous drive technology, enables the coordinated operation of dynamic molding and static shaping, allowing PTFE material to complete the corrugated structure molding during continuous pressing.

[0018] 2. The elastic sealing strip inside the dovetail groove is made of high-temperature resistant silicone material, which can achieve sealing while compensating for thermal expansion.

[0019] 3. A three-section independent temperature control system is installed outside the barrel to match the material phase change process, with segmented gradient control for the front plasticizing, middle molding, and rear shaping stages. The slider-type heating jacket is equipped with a quick-release flange structure to shorten mold changeover time. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of this utility model;

[0021] Figure 2 This is a schematic diagram of the internal structure of this utility model;

[0022] Figure 3 This is a schematic diagram of the structure of the segmented mold of this utility model;

[0023] In the diagram: 1-Extrusion mechanism, 2-Forming mechanism, 3-Cylinder, 4-Mandrel, 5-Segmented mold, 6-Push rod, 7-Power unit, 8-Step splicing assembly, 9-Dovetail groove, 10-Anti-overflow flange, 11-Hydraulic cylinder, 12-Piston end, 13-Elastic sealing strip, 14-Flange, 15-Annular positioning boss, 16-Internal cooling channel, 17-Pipeline, 18-Circulating cold source, 19-Heating jacket, 20-Bidirectional damper, 21-Lumber structure, 22-Slide groove, 23-Locking bolt. Detailed Implementation

[0024] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0025] Example 1

[0026] This embodiment provides a continuous extrusion molding device for PTFE corrugated pipes, such as... Figure 1-3As shown, the device includes an extrusion mechanism 1 and a molding mechanism 2 connected by a flange. Optionally, the extrusion mechanism 1 can be a single-screw extruder or a twin-screw extruder. The molding mechanism 2 includes a barrel 3, inside which a mandrel 4 is disposed. One end of the mandrel 4 is mounted to the end of the extrusion mechanism 1 via a connecting frame. Eight segmented molds 5 are evenly distributed around the barrel 3, each of which is a fan-shaped structure. The outer side of each mold segment is connected to the piston end of a hydraulic cylinder 11 via a push rod 6 that passes through the barrel. The hydraulic cylinder 11 is electrically connected to a controller via a reversing valve. Adjacent mold segments are radially slidingly connected by dovetail grooves 9, and anti-overflow flanges 10 are provided on the sides of the mold segments to prevent material from overflowing. The piston end 12 of the hydraulic cylinder 11 drives the push rod 6 to achieve synchronous opening and closing of the mold segments, forming a dynamically closed mold cavity. When the fluoroplastic paste extruded by the extrusion mechanism 1 forms a corrugated structure in the mold cavity, it encases the mandrel 4 to shape the internal structure of the PTFE corrugated tube. The mandrel 4 has a variable diameter bar that is thicker at the top and thinner at the bottom. The segmented mold 5 is distributed in the variable diameter section of the mandrel 4. During operation, the segmented mold 5 clamps the mandrel 4 to form half of the corrugated structure. As the material is pushed downward, the segmented mold 5 clamps the mandrel 4 again to form the second half of the corrugated structure, while simultaneously driving the material to form the unformed part of the first half of the corrugated structure.

[0027] Example 2

[0028] Based on Example 1, a high-temperature resistant silicone elastic sealing strip 13 is embedded in the dovetail groove 9 to compensate for the thermal expansion gap of the mold segments; a spiral internal cooling channel 16 is opened inside the mandrel 4, which is connected to a low-temperature water circulation cooling source 18 (water temperature 5-10℃) through a pipe 17. The circulation cooling source can adopt a circulating pump, compressor, or other structure to achieve cooling and shaping of the inner side of the PTFE bellows. The extrusion mechanism 1 is connected to the barrel 3 through a flange 14, and the flange mating surface is provided with an annular positioning boss 15 to ensure that the coaxiality error between the mandrel 4 and the mold 5 is ≤0.05mm.

[0029] Example 3

[0030] Based on Example 1, a three-section heating jacket 19 is installed on the outside of the cylinder 3: the front section (plasticizing zone) is set to a temperature of 380±5℃, the middle section (forming zone) to 365±5℃, and the rear section (setting zone) to 350±5℃. Each section's resistance wire module is independently electrically connected to the temperature control system. A bidirectional damper 20 is installed between the piston end 12 of the hydraulic cylinder 11 and the cylinder. The cylinder 3 is provided with a lug structure 21, and the bidirectional damper is embedded in the lug structure 21 to absorb the impact vibration during the mold opening and closing process. At the same time, it extends the cylinder wall thickness of the cylinder 3, thereby making the radial positioning of the push rod 6 more stable. The heating jacket 19 is slidably connected to the cylinder 3 through an axial sliding groove 22. After loosening the locking bolt 23, it can move axially in the cylinder, which facilitates the fine adjustment of the heating area.

[0031] This invention utilizes the synergistic effect of dynamic mold opening and closing, gradient temperature control, and rapid cooling and shaping to achieve continuous extrusion molding of fluoroplastic PTFE corrugated tubes. First, the fluoroplastic paste is pushed to the front end of the molding mechanism 2 via the extrusion mechanism 1. The heating jacket 19 at the front of the cylinder 3 is set to 380±5℃ to fully plasticize the material. The variable-diameter section of the mandrel 4 guides the material to wrap around and form a tubular blank. The hydraulic cylinder 11 drives the push rod 6, pushing the segmented mold 5 to close, forming a closed mold cavity. The mold cavity extrudes the blank, forming a half-corrugated structure on the surface of the mandrel 4. The heating jacket 19 in the middle of the cylinder is maintained at 365±5℃ to ensure material fluidity. The piston end 12 of the hydraulic cylinder 11 retracts, synchronously opening the segmented mold 5. The extrusion mechanism 1 continuously pushes the material, advancing the blank by half a corrugation length. The bidirectional damper 21 absorbs the impact of mold opening and closing, reducing vibration amplitude. The mold closes again, forming the next half-corrugated structure, while simultaneously filling in the unformed portion of the previous half-corrugation. The rear section heating jacket 19 of the cylinder cools to 350±5℃, stabilizing the material's shape. A 5-10℃ circulating cold source 18 is introduced into the internal cooling channel 16 of the mandrel 4, rapidly cooling the inner wall of the PTFE bellows to achieve initial shaping. The elastic sealing strip 13 within the dovetail groove 9 compensates for the thermal expansion gaps in the mold segments. The mold opens and closes at a frequency of 10-15 times per minute, continuously pushing the material to form a complete PTFE bellows.

[0032] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A continuous push forming device for four-fluorine corrugated pipes, comprising an extrusion mechanism (1) and a forming mechanism (2) arranged in sequence, characterized in that: The forming mechanism (2) comprises a barrel (3), a core rod (4) is arranged in the barrel (3), one end of the core rod (4) is connected to the connection position of the extrusion mechanism (1) and the forming mechanism (2); a plurality of split dies (5) are arranged in a circumferential array on the side wall of the barrel (3), the outer side of each split die (5) is connected with a push rod (6) in a radial direction, the push rod (6) is connected with a power device (7) penetrating through the barrel (3); the split dies (5) are combined to form a closed die cavity through a radially arranged stepped joint (8) between adjacent split dies (5).

2. The continuous push forming apparatus for four-fluoro bellows according to claim 1, wherein: The stepped joint (8) is a dovetail groove (9), and the side of each split die (5) is provided with an anti-overflow flange (10).

3. The continuous push forming apparatus for four-fluoro bellows according to claim 1, wherein: The power device (7) comprises a hydraulic cylinder (11), and the piston end (12) of the hydraulic cylinder (11) is connected to the push rod (6).

4. The continuous push forming apparatus for four-fluoro bellows according to claim 2, wherein: The dovetail groove (9) of the stepped joint (8) is embedded with an elastic sealing strip (13).

5. The continuous push forming apparatus for four-fluoro bellows according to claim 1, wherein: The extrusion mechanism (1) and the forming mechanism (2) are connected through a flange (14), and the abutting surface of the flange (14) is provided with an annular positioning boss (15).

6. The continuous push forming apparatus for four-fluoro bellows according to claim 1, wherein: The split die (5) is composed of 6-8 die segments, and the die segments are distributed at equal angles in the circumferential direction of the barrel (3).

7. The continuous push forming apparatus for four-fluoro bellows according to claim 1, wherein: The core rod (4) is internally provided with an internal cooling channel (16), and the internal cooling channel (16) is connected to a circulating cooling source (18) through a pipeline (17).

8. The continuous push forming apparatus for four-fluoro bellows according to claim 1, wherein: The barrel (3) is sleeved with a heating sleeve (19), three groups of independently temperature-controlled resistance wire modules are embedded in the heating sleeve (19), and the three groups of independently temperature-controlled resistance wire modules correspond to the front section, the middle section and the rear section of the barrel respectively; and the resistance wire modules are electrically connected with an external temperature control system.

9. The continuous push forming apparatus for four-fluoro bellows according to claim 3, wherein: The piston end (12) of the hydraulic cylinder (11) is sleeved with a bidirectional damper (20), and the bidirectional damper (20) is embedded on the lug structure (21) outside the barrel (3).

10. The continuous push forming apparatus for four-fluoro bellows according to claim 8, wherein: The heating sleeve (19) and the barrel (3) are connected through an axial sliding groove (22) and a sliding block, and the sliding groove (22) and the sliding block are fastened through a locking bolt (23) arranged in the radial direction of the barrel.

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