Forming device for low-smoke halogen-free cable sheath material

Abstract

The invention discloses a forming device for a low-smoke halogen-free cable sheath material, which comprises a mixing shell, the conical bottom wall of the mixing shell is communicated with a forming shell through a connecting pipe, and the forming device further comprises a mixing mechanism and a backflow mechanism; the mixing mechanism comprises a rotating shaft I, a spiral stirring blade, an annular seat, a rotating shaft II, a central stirring rod and a rotary sealing assembly, and the rotating shaft I is rotationally connected to the top wall of the mixing shell through a bearing I. According to the forming device for the low-smoke halogen-free cable sheath material, low-smoke halogen-free raw materials at a mixing part are mixed and flow in three flow states through elements, so that the forming efficiency is improved; through rich mixing flow states, the mixing degree of the low-smoke halogen-free raw materials is improved, meanwhile, through the elastic element, when too much low-smoke halogen-free raw materials at the extrusion forming part in the device are gathered, the redundant low-smoke halogen-free raw materials can automatically flow back to the mixing part, and therefore the low-smoke halogen-free raw materials can be fully mixed. And the pipeline at the extrusion molding part is prevented from being damaged due to overlarge pressure in the pipeline.

Description

Technical Field

[0001] The present invention relates to the technical field of cable sheath material forming, and specifically relates to a forming device for low-smoke and halogen-free cable sheath material. Background Art

[0002] Low-smoke and halogen-free refers to the outer sheath material of cables. The low-smoke and halogen-free cable sheath is made of thermoplastic or thermosetting compounds. These compounds have limited smoke generation, do not contain halogens, and do not produce harmful gases even when exposed to high-temperature sources. Therefore, the low-smoke and halogen-free sheath is relatively popular. When using the low-smoke and halogen-free sheath, the mixed molten low-smoke and halogen-free sheath material is covered on the outside of the cable core through a forming device and extruded and formed with an extrusion device. In the prior art: The patent with the authorized publication number CN 213260970 U discloses an extrusion device for irradiated cross-linked low-smoke and halogen-free insulation sheath material for photovoltaic cables, including a bottom plate, an extrusion tube, and an injection port. The extrusion tube is fixedly installed on the top surface of the bottom plate, and the injection port is fixedly installed on the top surface of the extrusion tube. A first motor is fixedly installed at the end of the extrusion tube. The output shaft of the first motor is fixedly installed with a rotating rod through the extrusion tube, and a first stirring blade is fixedly installed on the outer side of the rotating rod. Heating plates are fixedly installed on both sides inside the extrusion tube. In this extrusion device for irradiated cross-linked low-smoke and halogen-free insulation sheath material for photovoltaic cables, the motor at the end of the extrusion tube drives the rotating rod and the first stirring blade inside. Under the high-speed rotation of the motor, the first stirring blade inside plays a stirring role and can also push the plastic liquid inside forward. Moreover, heating plates are installed inside the extrusion tube to improve the fusion degree and softness of the plastic liquid inside during stirring, thereby improving efficiency. The low-smoke and halogen-free raw materials of this device are evenly mixed and stirred by a second stirring blade to avoid the situation where the low-smoke and halogen-free raw materials are not evenly mixed during use, resulting in incomplete melting of the materials and the presence of particles inside the materials, which will affect the flatness of the subsequent extrusion and forming of the low-smoke and halogen-free raw materials. However, the structure of the second stirring blade of this device is relatively simple, and the mixing effect on the low-smoke and halogen-free raw materials is limited, leaving room for improvement. At the same time, when the device is in use, the spiral design of the first stirring blade is used to convey the low-smoke and halogen-free raw materials to the extrusion part of the device. The space of the extrusion part of the device is limited. If the conveying speed of the low-smoke and halogen-free raw materials is greater than the consumption speed of the low-smoke and halogen-free raw materials at the extrusion part, then the low-smoke and halogen-free raw materials inside the extrusion part will become more and more. If the pressure between the low-smoke and halogen-free raw materials at the extrusion part is too high, it may cause the pipeline to be damaged due to excessive pressure. Therefore, we propose a forming device for low-smoke and halogen-free cable sheath material. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the existing defects and provide a forming device for low-smoke and halogen-free cable sheath materials. Through components, the low-smoke and halogen-free raw materials at the mixing part are mixed and flow in three flow states. Through the rich mixing flow states, the mixing degree between the low-smoke and halogen-free raw materials is improved. At the same time, through elastic components, when the low-smoke and halogen-free raw materials at the extrusion forming part in the device accumulate too much, the excess low-smoke and halogen-free raw materials can be automatically returned to the mixing part, avoiding the damage of the pipeline at the extrusion forming part due to excessive internal pressure, and effectively solving the problems in the background technology.

[0004] To achieve the above object, the present invention provides the following technical solution: A forming device for low-smoke and halogen-free cable sheath materials, including a mixing shell, the conical bottom wall of the mixing shell is connected to a forming shell through a connecting pipe, and further includes a mixing mechanism and a reflux mechanism; Mixing mechanism: It includes a first rotating shaft, spiral stirring blades, an annular seat, a second rotating shaft, a central stirring rod and a rotary sealing assembly. The first rotating shaft is rotatably connected to the top wall of the mixing shell through a first bearing. Spiral stirring blades are provided at both the upper and lower ends of the outer side of the first rotating shaft. The spiral directions of the two spiral stirring blades are opposite. An annular seat is provided in the middle of the first rotating shaft. Two symmetrically distributed central stirring rods are rotatably connected to the outside of the annular seat through the second rotating shaft. A rotary sealing assembly is provided between the second rotating shaft and the mixing shell; Reflux mechanism: It is arranged between the connecting pipe and the mixing shell. Through components, the low-smoke and halogen-free raw materials at the mixing part are mixed and flow in three flow states. Through the rich mixing flow states, the mixing degree between the low-smoke and halogen-free raw materials is improved. At the same time, through elastic components, when the low-smoke and halogen-free raw materials at the extrusion forming part in the device accumulate too much, the excess low-smoke and halogen-free raw materials can be automatically returned to the mixing part, avoiding the damage of the pipeline at the extrusion forming part due to excessive internal pressure.

[0005] Furthermore, it further includes a single-chip microcomputer. The single-chip microcomputer is located outside the mixing shell, and the input end of the single-chip microcomputer is electrically connected to an external power supply, which is convenient for controlling the electrical components in the device.

[0006] Furthermore, the rotary sealing assembly includes an annular shell, a bevel gear ring, bevel gears and a sliding ring. The annular shell is arranged in the middle of the inner wall of the mixing shell. A bevel gear ring is provided on the outer side wall of the annular shell. Bevel gears are provided at the ends of the second rotating shaft far from the center of the mixing shell. The bevel gears are all meshed with the bevel gear ring. The inner side wall of the annular shell is rotatably connected to the sliding ring through a large-diameter sealing bearing. The ends of the second rotating shaft far from the center of the mixing shell are rotatably connected to the sliding ring through sealing bearings, enabling the second rotating shaft in the forming device for low-smoke and halogen-free cable sheath materials to rotate around its own axis, and at the same time avoiding the interference of the low-smoke and halogen-free raw materials in the mixing shell on the meshing connection of the bevel gear ring and the bevel gears.

[0007] Furthermore, the mixing mechanism further includes a third rotating shaft and a spiral feeding sheet. The third rotating shaft is arranged at the bottom of the first rotating shaft, and a spiral feeding sheet is arranged at the lower end of the outer side of the third rotating shaft. The spiral feeding sheet is cooperatively installed with the connecting pipe to automatically convey the low-smoke and halogen-free raw materials to the extrusion part.

[0008] Furthermore, the mixing mechanism further includes a servo motor. The servo motor is arranged in the middle of the upper side of the mixing shell. The input end of the servo motor is electrically connected to the output end of the single-chip microcomputer. The output shaft of the servo motor is fixedly connected to the upper end of the first rotating shaft to supply power for mixing and stirring the low-smoke and halogen-free raw materials in the forming device for low-smoke and halogen-free cable sheathing materials.

[0009] Furthermore, the reflux mechanism includes a reflux pipe, a cross, a telescopic column, a spring, a plugging seat and a conical ring. The reflux pipe is arranged between the inner wall of the connecting pipe and the conical bottom wall of the mixing shell. The upper end of the inner part of the reflux pipe is successively provided with a cross and a conical ring from bottom to top. A plugging seat is arranged on the upper side of the cross through a telescopic column and a spring. The spring is movably sleeved on the outer end of the telescopic column. The plugging seat is cooperatively installed with the conical ring to automatically reflux the redundant low-smoke and halogen-free raw materials at the extrusion and forming part to the mixing part.

[0010] Furthermore, the reflux mechanism further includes a second heating sheet. The second heating sheet is uniformly arranged in the wall body of the reflux pipe. A first heating sheet is uniformly distributed in the wall body of the mixing shell. The input ends of the first heating sheet and the second heating sheet are both electrically connected to the output end of the single-chip microcomputer to prevent the low-smoke and halogen-free raw materials in the mixing shell and the reflux pipe in the forming device for low-smoke and halogen-free cable sheathing materials from being cured at low temperature.

[0011] Furthermore, a hollow plate is arranged at the left end inside the forming shell, and a rubber sealing ring is arranged on the right side of the hollow plate to prevent the low-smoke and halogen-free raw materials in the forming device for low-smoke and halogen-free cable sheathing materials from overflowing from the gap between the cable core and the middle circular hole of the hollow plate.

[0012] Furthermore, an annular inner cavity is formed at the right end of the wall body of the forming shell, and a spiral cooling pipe is arranged inside the annular inner cavity. The liquid inlet end and the liquid outlet end of the spiral cooling pipe both penetrate through the wall body of the forming shell and are exposed to the outside to cool and solidify the low-smoke and halogen-free raw materials at the extrusion and forming part of the device.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: The forming device for low-smoke and halogen-free cable sheathing materials has the following advantages: 1. When using the device to extrude and form the low-smoke and halogen-free sheath material on the outer side of the cable core, through the first rotating shaft, the spiral stirring blades, the annular seat, the second rotating shaft, the central stirring rod and the rotary sealing assembly, the low-smoke and halogen-free raw materials at the mixing part are in three mixing flow states: being conveyed from the upper end to the middle, being conveyed from the lower end to the middle, and being vertically stirred in the middle. The three flow states cooperate and blend with each other. Through the rich mixing flow states, the mixing degree among the low-smoke and halogen-free raw materials is improved, thereby avoiding the existence of particles due to uneven mixing of the raw materials, so as not to affect the flatness of the subsequent extrusion and forming of the low-smoke and halogen-free raw materials.

[0014] 2. When using the device to extrude and form the low-smoke and halogen-free sheath material on the outer side of the cable core, through the return pipe, the cross, the telescopic column, the spring, the plugging seat and the tapered ring, when the low-smoke and halogen-free raw materials at the extrusion and forming part in the device accumulate too much, the plugging part in the return pipe can be automatically opened due to the change of the pressure difference, so as to automatically return the redundant low-smoke and halogen-free raw materials at the extrusion and forming part to the mixing part, avoiding the damage of the pipeline at the extrusion and forming part due to excessive pressure in the pipe. Brief Description of the Drawings

[0015] Figure 1 It is a schematic structural diagram of the present invention; Figure 2 It is a schematic diagram of the internal structure of the present invention; Figure 3 It is a schematic sectional view of the present invention; Figure 4 It is a schematic structural diagram of the spiral cooling pipe of the present invention; Figure 5 It is a schematic diagram of the enlarged structure at A of the present invention; Figure 6 It is a schematic diagram of the enlarged structure at B of the present invention; Figure 7 It is a schematic diagram of the enlarged structure at C of the present invention.

[0016] In the figure: 1 mixing shell, 2 single-chip microcomputer, 3 connecting pipe, 4 forming shell, 5 mixing mechanism, 51 first rotating shaft, 52 spiral stirring blades, 53 annular seat, 54 second rotating shaft, 55 central stirring rod, 56 rotary sealing assembly, 561 annular shell, 562 bevel gear ring, 563 bevel gear, 564 slip ring, 57 third rotating shaft, 58 spiral feeding piece, 59 servo motor, 6 first heating sheet, 7 return mechanism, 71 return pipe, 72 cross, 73 telescopic column, 74 spring, 75 plugging seat, 76 tapered ring, 77 second heating sheet, 8 hollow plate, 9 rubber sealing ring, 10 annular inner cavity, 11 spiral cooling pipe. Detailed Embodiment

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0018] Please refer to Figure 1-7 , this embodiment provides a technical solution: a forming device for a low-smoke and halogen-free cable sheath material, including a mixing shell 1. The conical bottom wall of the mixing shell 1 is connected to a forming shell 4 through a connecting pipe 3. It also includes a single-chip microcomputer 2, which is located outside the mixing shell 1. The input end of the single-chip microcomputer 2 is electrically connected to an external power supply. A hollow plate 8 is provided at the left end inside the forming shell 4, and a rubber sealing ring 9 is provided on the right side of the hollow plate 8. An annular inner cavity 10 is opened at the right end of the wall of the forming shell 4, and a spiral cooling pipe 11 is provided inside the annular inner cavity 10. The liquid inlet end and the liquid outlet end of the spiral cooling pipe 11 both pass through the wall of the forming shell 4 and are exposed to the outside. When using the device to extrude and form a low-smoke and halogen-free sheath material on the outside of the cable core, first, the molten low-smoke and halogen-free sheath material is transported into the mixing shell 1 through the feed pipe at the top of the mixing shell 1. The external coolant inlet pipe and outlet pipe are respectively connected to the liquid inlet end and the liquid outlet end of the spiral cooling pipe 11. Subsequently, through an external feeding device, the cable core horizontally passes through the middle of the forming shell 4 from left to right. During this process, the cable core passes through the middle circular hole of the hollow plate 8, and the diameter of the cable core is the same as the diameter of the middle circular hole of the hollow plate 8. The rubber sealing ring 9 seals the gap between the cable core and the middle circular hole of the hollow plate 8 when the cable core passes through it, avoiding that when the subsequent low-smoke and halogen-free sheath material is formed, some low-smoke and halogen-free raw materials overflow through the gap under a certain pressure. It also includes a mixing mechanism 5 and a reflux mechanism 7; Mixing mechanism 5: It includes a first rotating shaft 51, spiral stirring blades 52, an annular seat 53, a second rotating shaft 54, a central stirring rod 55 and a rotary sealing assembly 56. The first rotating shaft 51 is rotatably connected to the top wall of the mixing shell 1 through a first bearing. Spiral stirring blades 52 are provided at both the upper and lower ends on the outer side of the first rotating shaft 51. The spiral directions of the two spiral stirring blades 52 are opposite. An annular seat 53 is provided in the middle of the first rotating shaft 51. Two symmetrically distributed central stirring rods 55 are rotatably connected to the outside of the annular seat 53 through the second rotating shaft 54. A rotary sealing assembly 56 is provided between the second rotating shaft 54 and the mixing shell 1. The rotary sealing assembly 56 includes an annular shell 561, a bevel gear ring 562, bevel gears 563 and a slip ring 564. The annular shell 561 is arranged in the middle of the inner wall of the mixing shell 1. A bevel gear ring 562 is provided on the outer side wall of the annular shell 561. Bevel gears 563 are provided at the ends of the second rotating shaft 54 away from the center of the mixing shell 1. The bevel gears 563 are all meshed with the bevel gear ring 562. The inner side wall of the annular shell 561 is rotatably connected to the slip ring 564 through a large-diameter sealing bearing. The ends of the second rotating shaft 54 away from the center of the mixing shell 1 are rotatably connected to the slip ring 564 through sealing bearings. The mixing mechanism 5 further includes a third rotating shaft 57 and spiral feeding blades 58. The third rotating shaft 57 is arranged at the bottom of the first rotating shaft 51. Spiral feeding blades 58 are provided at the lower end on the outer side of the third rotating shaft 57. The spiral feeding blades 58 are cooperatively installed with the connecting pipe 3. The mixing mechanism 5 further includes a servo motor 59. The servo motor 59 is arranged in the middle on the upper side of the mixing shell 1. The input end of the servo motor 59 is electrically connected to the output end of the single-chip microcomputer 2. The output shaft of the servo motor 59 is fixedly connected to the upper end of the first rotating shaft 51. The single-chip microcomputer 2 starts the servo motor 59 to drive its output shaft to drive the first rotating shaft 51 to rotate reversely. The first rotating shaft 51 drives the upper and lower spiral stirring blades 52 to rotate reversely at the same time. The upper spiral stirring blade 52 uses its spiral surface through reverse rotation to convey the low-smoke and halogen-free raw materials at the upper end inside the mixing shell 1 to the central part of the mixing shell 1. The lower spiral stirring blade 52 uses its spiral surface through reverse rotation to convey the low-smoke and halogen-free raw materials at the lower end inside the mixing shell 1 to the central part of the mixing shell 1. At the same time, the first rotating shaft 51 makes the second rotating shaft 54 drive the central stirring rod 55 to revolve around the axis of the mixing shell 1 through the annular seat 53. During the revolution of the second rotating shaft 54, through the meshing connection between the bevel gear 563 and the bevel gear ring 562, the second rotating shaft 54 drives the central stirring rod 55 to rotate around its own axis while revolving around the axis of the first rotating shaft 51 (when the second rotating shaft 54 revolves around the axis of the first rotating shaft 51, it drives the slip ring 564 to rotate synchronously along the inner wall of the annular shell 561. Through the structural design of the slip ring 564 and the annular shell 561, the low-smoke and halogen-free raw materials inside the mixing shell 1 are prevented from entering the annular shell 561 and interfering with the meshing between the bevel gear 563 and the bevel gear ring 562), so as to mix and stir the low-smoke and halogen-free raw materials moving from the upper and lower ends to the vertical middle part inside the mixing shell 1. Through the mixing flow state of various low-smoke and halogen-free raw materials inside the mixing shell 1, the low-smoke and halogen-free raw materials are fully mixed with each other.To avoid the phenomenon of particles existing on the forming surface during the subsequent extrusion molding of the low-smoke and halogen-free sheath material on the outer side of the cable core, during the mixing process of the low-smoke and halogen-free raw materials in the mixing shell 1, the first rotating shaft 51 drives the spiral feeding blade 58 to rotate reversely through the third rotating shaft 57. During the reverse rotation of the spiral feeding blade 58, the low-smoke and halogen-free raw materials at the conical bottom of the mixing shell 1 are conveyed upward through its own spiral surface, avoiding the low-smoke and halogen-free raw materials from entering the connecting pipe 3 at this time. At the same time, the single-chip microcomputer 2 starts the first heating sheet 6 to heat the inner cavity of the mixing shell 1, avoiding the curing phenomenon of the low-smoke and halogen-free raw materials in the mixing shell 1. When the low-smoke and halogen-free raw materials in the mixing shell 1 are evenly mixed, the single-chip microcomputer 2 starts the servo motor 59 so that its output shaft drives the first rotating shaft 51 to rotate forward. The first rotating shaft 51 drives the spiral feeding blade 58 to rotate forward through the third rotating shaft 57. During the forward rotation of the spiral feeding blade 58, the low-smoke and halogen-free raw materials at the bottom wall of the mixing shell 1 are conveyed through the connecting pipe 3 to the middle of the forming shell 4. The low-smoke and halogen-free raw materials fill the middle cavity of the forming shell 4. Through the components of this device, the low-smoke and halogen-free raw materials at the mixing part are mixed and flow in three flow states. Through the rich mixing flow states, the mixing degree between the low-smoke and halogen-free raw materials is improved; Return mechanism 7: It is arranged between the connecting pipe 3 and the mixing shell 1. The return mechanism 7 includes a return pipe 71, a cross 72, a telescopic column 73, a spring 74, a plugging seat 75 and a conical ring 76. The return pipe 71 is arranged between the inner wall of the connecting pipe 3 and the conical bottom wall of the mixing shell 1. Inside the upper end of the return pipe 71, a cross 72 and a conical ring 76 are successively arranged from bottom to top. Above the cross 72, a plugging seat 75 is arranged through a telescopic column 73 and a spring 74. The spring 74 is movably sleeved on the outer end of the telescopic column 73. The plugging seat 75 is installed in cooperation with the conical ring 76. The return mechanism 7 further includes a second heating sheet 77, which is evenly arranged in the wall body of the return pipe 71. In the wall body of the mixing shell 1, there are evenly distributed first heating sheets 6. The input ends of the first heating sheets 6 and the second heating sheets 77 are electrically connected to the output end of the single-chip microcomputer 2. When the low-smoke and halogen-free raw material fills the middle cavity of the forming shell 4, the cable core is horizontally conveyed from left to right through an external feeding device. The low-smoke and halogen-free raw material in the forming shell 4 wraps around the outside of the cable core and moves to the right along with the cable core. At the same time, through an external coolant inlet pipe and outlet pipe, the coolant enters the spiral cooling pipe 11, and the spiral cooling pipe 11 uses heat transfer to cool and solidify the low-smoke and halogen-free raw material extruded and attached to the outside of the cable core passing through this part. Since the low-smoke and halogen-free raw material at the right end inside the forming shell 4 in the cooling part of the spiral cooling pipe 11 is in a cooled and solidified state and is in close contact with the inner wall at the right end inside the forming shell 4, the low-smoke and halogen-free raw material in the middle cavity of the forming shell 4 cannot be discharged through the right end of the forming shell 4. Therefore, the low-smoke and halogen-free raw material in the middle cavity of the forming shell 4 is in a compacted state. The spiral feeding blade 58 rotates forward, so that the low-smoke and halogen-free raw material conveyed into the forming shell 4 through the connecting pipe 3 is compacted and in a certain pressure state. When the low-smoke and halogen-free raw material between the connecting pipe 3 and the forming shell 4 is extruded to a certain state, the low-smoke and halogen-free raw material at this part enters the inside of the return pipe 71 and exerts an upward pressure on the plugging seat 75. When this pressure reaches a certain level, the plugging seat 75 overcomes the tensile elastic force exerted on it by the spring 74 and the vertical downward pressure exerted on it by the low-smoke and halogen-free raw material in the mixing shell 1 above the plugging seat 75. At this time, the plugging seat 75 moves upward, the telescopic end of the telescopic column 73 and the spring 74 stretch. By the upward movement of the plugging seat 75, the plugging of the conical ring 76 is released, so that the low-smoke and halogen-free raw material between the connecting pipe 3 and the forming shell 4 flows back to the inside of the mixing shell 1 through the return pipe 71, avoiding the phenomenon of pipeline damage due to excessive pressure of the low-smoke and halogen-free raw material between the connecting pipe 3 and the forming shell 4. At the same time, the single-chip microcomputer 2 starts the second heating sheet 77 to heat the inside of the return pipe 71, avoiding the solidification phenomenon of the low-smoke and halogen-free raw material in the return pipe 71. During the use of the forming device for low-smoke and halogen-free cable sheath material, the single-chip microcomputer 2 regulates the transmission power of the first heating sheets 6 and the second heating sheets 77 to ensure that the temperature in the mixing shell 1 and the return pipe 71 is within an appropriate range. The device uses elastic elements. When too much low-smoke and halogen-free raw material accumulates at the extrusion and forming part inside the device,It can automatically reflux the redundant low-smoke and halogen-free raw materials to the mixing part, avoiding the damage of the pipes at the extrusion molding part due to excessive internal pressure in the pipes.

[0019] The working principle of a forming device for a low-smoke and halogen-free cable sheath material provided by the present invention is as follows: When using the device to extrude and form the low-smoke and halogen-free sheath material on the outside of the cable core, first, the molten low-smoke and halogen-free sheath material is transported into the mixing shell 1 through the feed pipe at the top of the mixing shell 1. The external coolant inlet pipe and outlet pipe are respectively connected to the inlet end and outlet end of the spiral cooling pipe 11. Subsequently, through the external feeding device, the cable core horizontally passes through the middle of the forming shell 4 from left to right. During this process, the cable core passes through the middle circular hole of the hollow plate 8, and the diameter of the cable core is the same as that of the middle circular hole of the hollow plate 8. The rubber sealing ring 9 seals the gap between the cable core and the middle circular hole of the hollow plate 8 when the cable core passes through it, to prevent part of the low-smoke and halogen-free raw material from overflowing through this gap under a certain pressure during the subsequent forming of the low-smoke and halogen-free sheath material. The single-chip microcomputer 2 starts the servo motor 59, and its output shaft drives the first rotating shaft 51 to rotate reversely. The first rotating shaft 51 drives the upper and lower spiral stirring blades 52 to rotate reversely at the same time. The upper spiral stirring blade 52 uses its spiral surface through reverse rotation to transport the low-smoke and halogen-free raw material at the upper end inside the mixing shell 1 to the central part of the mixing shell 1. The lower spiral stirring blade 52 uses its spiral surface through reverse rotation to transport the low-smoke and halogen-free raw material at the lower end inside the mixing shell 1 to the central part of the mixing shell 1. At the same time, the first rotating shaft 51 enables the second rotating shaft 54 to drive the central stirring rod 55 to revolve around the axis of the mixing shell 1 through the annular seat 53. During the revolution of the second rotating shaft 54, through the meshing connection between the bevel gear 563 and the bevel gear ring 562, the second rotating shaft 54 drives the central stirring rod 55 to rotate around its own axis while revolving around the axis of the first rotating shaft 51 (when the second rotating shaft 54 revolves around the axis of the first rotating shaft 51, it drives the slip ring 564 to rotate synchronously along the inner wall of the annular shell 561. Through the structural design of the slip ring 564 and the annular shell 561, the low-smoke and halogen-free raw material inside the mixing shell 1 is prevented from entering the annular shell 561 and interfering with the meshing between the bevel gear 563 and the bevel gear ring 562), so as to mix and stir the low-smoke and halogen-free raw material moving from the upper and lower ends to the vertical middle part inside the mixing shell 1. Through the mixed flow state of various low-smoke and halogen-free raw materials inside the mixing shell 1, the low-smoke and halogen-free raw materials are fully mixed, avoiding the phenomenon of particles on the forming surface during the subsequent extrusion and forming of the low-smoke and halogen-free sheath material on the outside of the cable core. During the mixing process of the low-smoke and halogen-free raw material inside the mixing shell 1, the first rotating shaft 51 drives the spiral feeding blade 58 to rotate reversely through the third rotating shaft 57. During the reverse rotation of the spiral feeding blade 58, it transports the low-smoke and halogen-free raw material at the conical bottom of the mixing shell 1 upward through its spiral surface, preventing the low-smoke and halogen-free raw material from entering the connecting pipe 3 at this time. At the same time, the single-chip microcomputer 2 starts the first heating sheet 6 to heat the inner cavity of the mixing shell 1, preventing the low-smoke and halogen-free raw material inside the mixing shell 1 from solidifying. When the low-smoke and halogen-free raw material inside the mixing shell 1 is evenly mixed, the single-chip microcomputer 2 starts the servo motor 59, and its output shaft drives the first rotating shaft 51 to rotate forward. The first rotating shaft 51 drives the spiral feeding blade 58 to rotate forward through the third rotating shaft 57.During the forward rotation of the spiral feeding piece 58, through its own spiral surface, the low-smoke and halogen-free raw material at the bottom wall of the mixing shell 1 is conveyed through the connecting pipe 3 to the middle part of the forming shell 4. The low-smoke and halogen-free raw material fills the middle cavity of the forming shell 4. At the same time, the cable core is horizontally conveyed from left to right through an external feeding device. The low-smoke and halogen-free raw material in the forming shell 4 wraps around the outside of the cable core and moves to the right along with the cable core. At the same time, through the external coolant inlet pipe and outlet pipe, the coolant enters the spiral cooling pipe 11. Through the spiral cooling pipe 11, heat transfer is used to cool and solidify the low-smoke and halogen-free raw material extruded and attached to the outside of the cable core passing through this part. Since the low-smoke and halogen-free raw material at the cooling part of the spiral cooling pipe 11 at the right end inside the forming shell 4 is in a cooled and solidified state and is in close contact with the inner wall at the right end of the forming shell 4, the low-smoke and halogen-free raw material in the middle cavity of the forming shell 4 cannot be discharged through the right end of the forming shell 4. Therefore, the low-smoke and halogen-free raw material in the middle cavity of the forming shell 4 is in a compacted state. Due to the forward rotation, the spiral feeding piece 58 compacts the low-smoke and halogen-free raw material conveyed into the forming shell 4 through the connecting pipe 3 and is in a certain pressure state. When the low-smoke and halogen-free raw material between the connecting pipe 3 and the forming shell 4 is extruded to a certain state, the low-smoke and halogen-free raw material at this part enters the inside of the return pipe 71 and exerts an upward pressure on the plugging seat 75. When this pressure reaches a certain level, the plugging seat 75 overcomes the tensile elastic force exerted on it by the spring 74 and the vertical downward pressure exerted on it by the low-smoke and halogen-free raw material in the mixing shell 1 above the plugging seat 75. At this time, the plugging seat 75 moves upward, the telescopic end of the telescopic column 73 and the spring 74 are stretched. By the upward movement of the plugging seat 75, the plugging of the conical ring 76 is released, so that the low-smoke and halogen-free raw material between the connecting pipe 3 and the forming shell 4 flows back to the inside of the mixing shell 1 through the return pipe 71, avoiding the pipeline breakage phenomenon of the low-smoke and halogen-free raw material between the connecting pipe 3 and the forming shell 4 due to excessive pressure. At the same time, the single-chip microcomputer 2 starts the heating sheet two 77 to heat the inside of the return pipe 71, avoiding the solidification phenomenon of the low-smoke and halogen-free raw material in the return pipe 71. During the use of the forming device for low-smoke and halogen-free cable sheath material, the single-chip microcomputer 2 regulates the feeding power of the heating sheet one 6 and the heating sheet two 77 to ensure that the temperatures in the mixing shell 1 and the return pipe 71 are within an appropriate range.,

[0020] It should be noted that, in the above embodiments, the single-chip microcomputer 2 disclosed can adopt MCS-51, the servo motor 59 can adopt DT-D02, and both the heating sheet one 6 and the heating sheet two 77 can adopt MCH ceramic heating sheets. The single-chip microcomputer 2 controls the servo motor 59, the heating sheet one 6, and the heating sheet two 77 to work using the methods commonly used in the prior art.

[0021] The above are only embodiments of the present invention, and thus do not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present invention.

Claims

1. A forming device for a low-smoke and halogen-free cable sheath material, comprising a mixing shell (1), the conical bottom wall of the mixing shell (1) is communicated with a forming shell (4) through a connecting pipe (3), and it is characterized in that: It further includes a mixing mechanism (5) and a reflux mechanism (7); Mixing mechanism (5): It includes a first rotating shaft (51), spiral stirring blades (52), an annular seat (53), a second rotating shaft (54), a central stirring rod (55) and a rotary seal assembly (56). The first rotating shaft (51) is rotatably connected to the top wall of the mixing shell (1) through a first bearing. Spiral stirring blades (52) are provided at both the upper and lower ends of the outer side of the first rotating shaft (51). The spiral directions of the two spiral stirring blades (52) are opposite. An annular seat (53) is provided in the middle of the first rotating shaft (51). Two symmetrically distributed central stirring rods (55) are rotatably connected to the outer side of the annular seat (53) through the second rotating shaft (54). A rotary seal assembly (56) is provided between the second rotating shaft (54) and the mixing shell (1); Reflux mechanism (7): It is arranged between the connecting pipe (3) and the mixing shell (1).

2. The forming device for a low-smoke and halogen-free cable sheath material according to claim 1, wherein: It further includes a single-chip microcomputer (2). The single-chip microcomputer (2) is located outside the mixing shell (1), and the input end of the single-chip microcomputer (2) is electrically connected to an external power supply.

3. The forming device for a low-smoke and halogen-free cable sheath material according to claim 1, wherein: The rotary seal assembly (56) includes an annular shell (561), a bevel gear ring (562), bevel gears (563) and a slip ring (564). The annular shell (561) is arranged in the middle of the inner wall of the mixing shell (1). A bevel gear ring (562) is provided on the outer side wall of the annular shell (561). Bevel gears (563) are provided at the ends of the second rotating shaft (54) far from the center of the mixing shell (1). The bevel gears (563) are all meshed and connected with the bevel gear ring (562). A slip ring (564) is rotatably connected to the inner side wall of the annular shell (561) through a large-diameter seal bearing. The ends of the second rotating shaft (54) far from the center of the mixing shell (1) are all rotatably connected to the slip ring (564) through seal bearings.

4. A forming device for a low-smoke and halogen-free cable sheath material according to claim 1, characterized in that: The mixing mechanism (5) further includes a third rotating shaft (57) and a spiral feeding sheet (58). The third rotating shaft (57) is arranged at the bottom of the first rotating shaft (51). A spiral feeding sheet (58) is provided at the lower end of the outer side of the third rotating shaft (57). The spiral feeding sheet (58) is cooperatively installed with the connecting pipe (3).

5. The forming device for a low-smoke and halogen-free cable sheath material according to claim 2, wherein: The mixing mechanism (5) further includes a servo motor (59). The servo motor (59) is arranged in the middle of the upper side of the mixing shell (1). The input end of the servo motor (59) is electrically connected to the output end of the single-chip microcomputer (2), and the output shaft of the servo motor (59) is fixedly connected to the upper end of the first rotating shaft (51).

6. The forming device for a low-smoke and halogen-free cable sheath material according to claim 2, characterized in that: The reflux mechanism (7) includes a reflux pipe (71), a cross (72), a telescopic column (73), a spring (74), a plugging seat (75) and a tapered ring (76). The reflux pipe (71) is arranged between the inner wall of the connecting pipe (3) and the tapered bottom wall of the mixing shell (1). A cross (72) and a tapered ring (76) are successively arranged from bottom to top at the upper end inside the reflux pipe (71). A plugging seat (75) is provided on the upper side of the cross (72) through a telescopic column (73) and a spring (74). The spring (74) is movably sleeved on the outer end of the telescopic column (73). The plugging seat (75) is cooperatively installed with the tapered ring (76).

7. The forming device for a low-smoke and halogen-free cable sheath material according to claim 6, characterized in that: The reflux mechanism (7) further includes a second heating sheet (77), the second heating sheet (77) is uniformly arranged inside the wall of the reflux pipe (71), a first heating sheet (6) is uniformly distributed inside the wall of the mixing shell (1), and the input ends of the first heating sheet (6) and the second heating sheet (77) are both electrically connected to the output end of the single-chip microcomputer (2).

8. A molding device for a low-smoke and halogen-free cable sheath material according to claim 1, characterized in that: A hollow plate (8) is provided at the left end inside the forming shell (4), and a rubber sealing ring (9) is provided on the right side of the hollow plate (8).

9. The forming device for a low-smoke and halogen-free cable sheath material according to claim 1, characterized in that: An annular inner cavity (10) is formed at the right end of the wall of the forming shell (4), a spiral cooling pipe (11) is arranged inside the annular inner cavity (10), and the liquid inlet end and the liquid outlet end of the spiral cooling pipe (11) both penetrate through the wall of the forming shell (4) and are exposed to the outside.

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