Temperature loss prevention extrusion die and plastic extruder

Abstract

The invention relates to the technical field of cable production, in particular to an anti-temperature-loss extrusion die and a plastic extruder, the anti-temperature-loss extrusion die comprises a die sleeve and a die core, and the die sleeve is provided with a through hole penetrating in the axial direction of the die sleeve; the die core is arranged in the through hole, an extrusion channel is formed between the outer wall of the die core and the inner wall of the die sleeve, the die core is provided with a center hole penetrating in the axial direction of the die core, the center hole is used for allowing a cable core to penetrate through, the face, close to the center hole, of the die core is an inner ring face, the face, away from the center hole, of the die core is an outer ring face, and a heat insulation cavity is formed between the inner ring face and the outer ring face. The radial temperature of the pipe wall of the mold core can be effectively prevented from being reduced from inside to outside, the outer ring surface of the mold core can keep the optimal extrusion temperature of polymer melt as far as possible, when the molten polymer flows to the pipe wall, the smoothness of a runner is not influenced by cooling, the molten polymer can be uniformly extruded on a conductor or a cable core, and the production efficiency is improved. And an insulation or a sheath of the cable is formed through cooling and curing, so that the insulation or the sheath is prevented from being eccentric, or the phenomena of hole breaking, disjunction and the like are prevented.

Description

Technical Field

[0001] The present application relates to the technical field of cable production, and in particular to an anti-loss of temperature extrusion die and a plastic extruder. Background Art

[0002] The insulation and sheath of the cable are usually plastic polymers. During production, plastic extruders and molds are used to extrude the molten plastic polymer onto the conductor or cable core. The molten plastic is then solidified onto the conductor or cable core through water cooling and other methods to form the insulation or sheath of the cable. However, the conductors are all made of metal materials, and the cable core often has metal materials such as armor. During the extrusion process, the conductor or cable core's pay-off, extruder mold, and take-up positions are arranged in an approximately horizontal straight line, with the extrusion mold in the middle. Although there is a certain tension between pay-off and take-up, due to the effect of gravity, the conductor or cable core sags a little at the mold position, causing the conductor or cable core to contact the bottom edge of the mold core wall. The conductor is generally copper or aluminum, and the armor layer on the cable core is usually steel strips. The thermal conductivity of copper, aluminum, and steel is approximately 4, respectively. 01, 237, 50W / m·k, the thermal conductivity is large, the wall of the core is relatively thin, and the heat capacity is small. In this way, when it is touched by metal materials at room temperature, the temperature of the wall is quickly taken away. Especially for large-sized cables and when produced in winter, the core loses temperature more seriously, causing the end of the core wall to be not much higher than the ambient temperature. In this way, the molten polymer is rapidly cooled in the extrusion flow channel, and local solidification is hindered, so it cannot be evenly extruded onto the conductor or cable core, causing eccentricity of the insulation or sheath. In severe cases, holes and disconnection are formed.

[0003] In order to prevent this phenomenon, the traditional approach is to apply greater tension between the release and the pulling, so that the conductor or cable core is as straight as possible, reduce the sagging of the conductor or cable core in the mold, thereby reducing the frequency of contact between the conductor or cable core and the mold, and prevent the occurrence of temperature loss; second, the mold is enlarged. For example, the normal mold core aperture is usually 1-3mm larger than the outer diameter of the conductor and 3-5mm larger than the outer diameter of the cable core. After the enlargement, it is 3-5mm larger than the maximum diameter of the conductor and 5-8mm larger than the cable core, and the mold sleeve is also enlarged accordingly. Then the head of the machine is tilted downward to make the conductor or cable core contact the root of the mold tube wall in a point-like manner. Due to the small contact area, the temperature loss is also less.

[0004] The existing practice has the following shortcomings: first, to increase the tension, a high-power traction machine needs to be added, which wastes space and energy and has high production costs. Even so, when large-sized cables are produced in winter, the conductor or cable core will still frequently touch the mold core, and temperature loss often occurs; second, after the mold specifications are increased, the eccentricity is serious; the machine head is tilted downward, which is not only unsightly, but also varies from person to person, and it is difficult to master the angles for different specifications. Even if a certain specification cable is tilted downward to the so-called optimal angle so that the molten polymer can be extruded from the mold at a uniform speed, the extruded polymer also follows the downward tilt of the mold, and when it is extruded onto the conductor or cable core, it is also at an angle, which easily causes the extrudate to be eccentric. In this way, the product quality cannot be fundamentally guaranteed, the manufacturing cost is high, and the production efficiency is low. Therefore, an anti-temperature extrusion mold is needed to meet people's needs. Summary of the invention

[0005] The present application provides an anti-loss of temperature extrusion die and a plastic extruder, which are used to solve the problem in the prior art that the molten polymer is rapidly cooled in the extrusion flow channel, local solidification is hindered, and it cannot be evenly extruded onto the conductor or cable core, causing insulation or sheath eccentricity, or even holes and disconnection.

[0006] On the one hand, the present application provides an anti-loss of temperature extrusion die, comprising: The mold sleeve has a through hole penetrating along its axial direction; The mold core is arranged in the through hole, and an extrusion channel is formed between the outer wall of the mold core and the inner wall of the mold sleeve. The mold core has a center hole that penetrates along its own axis, and the center hole is used for the cable core to pass through. The side of the mold core close to the center hole is the inner annular surface, and the side of the mold core away from the center hole is the outer annular surface. An insulating cavity is formed between the inner annular surface and the outer annular surface.

[0007] In a possible design, an annular groove recessed along the axial direction of the mold core is formed on the extrusion end surface of the mold core, a sealing cover is provided at the notch of the annular groove, and the sealing cover and the annular groove together form a heat-insulating cavity.

[0008] In a possible design, the depth of the annular groove is greater than the axial length of the extrusion section of the die core.

[0009] In a possible design, the anti-loss of temperature extrusion die also includes a heat-distributing pipe, which is an annular pipe coaxial with the mold core and is arranged inside or on the surface of the mold core. The heat-distributing pipe is filled with a heat-conducting medium.

[0010] In a possible design, the two opposite ends of the heat pipe are an evaporation section and a condensation section, respectively, and a liquid absorption core is arranged between the evaporation section and the condensation section.

[0011] In a possible design, a limiting annular groove is formed on the inner wall of the annular groove close to the extrusion channel, and the heat-distributing pipe is passed through the limiting annular groove.

[0012] In one possible design, the heat dissipating pipe includes a first tube body and a second tube body, the first tube body and the second tube body are respectively arc-shaped tubes, a spring is arranged between the ends of the first tube body and the second tube body, the first tube body, the second tube body and the spring together form a closed ring, and the spring can generate elastic deformation to enable the first tube body and the second tube body to be respectively stuck in the limiting ring groove.

[0013] In one possible design, the anti-thermal extrusion die also includes a heat conductive plate, which is evenly arranged in the extrusion channel along the circumferential direction. The heat conductive plate has an inner edge and an outer edge that are relatively arranged. The inner edge is connected to the outer wall of the mold core, and the outer edge is connected to the inner wall of the mold sleeve.

[0014] In a possible design, the heat conductive sheet has a front edge and a rear edge, and the width of the front edge gradually decreases along the extrusion direction.

[0015] On the other hand, the present application also provides a plastic extruder, comprising the anti-loss of temperature extrusion die as described above.

[0016] The beneficial effects of this application are as follows: The anti-thermal extrusion die of the present application forms a heat-insulating cavity between the outer annular surface and the inner annular surface of the mold core to separate the inner annular surface of the mold core from the outer annular surface. When the normal temperature conductor or the metal material of the cable core touches the lower edge of the inner wall of the mold core, the temperature of the inner annular surface of the mold core decreases accordingly. Since the inside of the hollow heat-insulating cavity is air, and the thermal conductivity of air is about 0.023 W / m·k, it can effectively isolate the radial temperature drop of the mold core tube wall from the inside to the outside. In this way, the outer annular surface of the mold core can maintain the optimal extrusion temperature of the polymer melt as much as possible. When the molten polymer flows to this tube wall, the smooth flow of the flow channel is not affected by the temperature drop, and it can be evenly extruded onto the conductor or cable core, and the insulation or sheath of the cable is formed after cooling and solidification, without causing eccentricity of the insulation or sheath, or forming holes, disconnection and the like, thereby ensuring the quality of the product.

[0017] By providing a uniform heat pipe on the mold core, the uniform heat pipe is an annular tube coaxial with the mold core. The heat-conducting medium in the uniform heat pipe can balance the temperature of the lower edge and the upper edge of the mold core, which is beneficial to keep the circumferential temperature of the mold core consistent, thereby ensuring that the flow rate of the polymer melt flowing through the coaxial position and different radial positions of the mold core is as consistent as possible, so that the thickness of the insulation or sheath at the coaxial position and different radial positions of the cable core is consistent, thereby improving the concentricity of the cable core and the insulation or sheath.

[0018] By arranging a heat conductive sheet in the extrusion channel, the inner edge of the heat conductive sheet is connected to the outer wall of the mold core, and the outer edge of the heat conductive sheet is connected to the inner wall of the mold sleeve, so that the temperature of the mold core and the mold sleeve can be balanced, avoiding holes and disconnection caused by the mold core temperature being lower than the mold sleeve.

[0019] The plastic extruder provided in the present application includes the anti-loss of temperature extrusion die in the present application, and therefore also includes all the above-mentioned advantages of the anti-loss of temperature extrusion die. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 A schematic diagram of the structure of an anti-loss of temperature extrusion die provided in an embodiment of the present application; Figure 2 for Figure 1 A schematic diagram of the structure enlarged at B in the middle; Figure 3 for Figure 1 Sectional view at AA in the middle; Figure 4 A schematic diagram of the structure of a heat-dissipating pipe for an anti-loss of temperature extrusion die provided in an embodiment of the present application; Figure 5 A schematic diagram of the structure of a heat-dissipating pipe for an anti-loss of temperature extrusion die provided in an embodiment of the present application; Figure 6 for Figure 3 Sectional view at CC; Figure 7 A schematic diagram of the structure of a heat-conducting sheet for an anti-temperature loss extrusion die provided in an embodiment of the present application; Figure 8 A schematic diagram of the structure of a heat-conducting sheet for an anti-temperature loss extrusion die provided in an embodiment of the present application; Fig. 9 It is a schematic diagram of the extrusion state of the polymer melt when the core temperature is lower than the sleeve temperature; Fig.10 It is the molding state of the polymer melt on the cable core when the mold core temperature is lower than the mold sleeve temperature.

[0022] Reference numerals: 100, mold sleeve; 200, mold core; 210, center hole; 220, inner annular surface; 230, outer annular surface; 240, heat insulation cavity; 250, annular groove; 251, limiting annular groove; 260, sealing cover; 300, extrusion channel; 400, cable core; 500, uniform heat pipe; 510, evaporation section; 520, condensation section; 530, liquid absorption core; 540, first tube body; 540, second tube body; 550, spring; 600, heat conductive plate; 610, inner edge; 620, outer edge; 630, front edge; 640, rear edge. DETAILED DESCRIPTION

[0023] The technical solution of the present application will be described clearly and completely below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0024] Combine the following Figure 1-Figure 10 , describing the anti-temperature loss extrusion die provided in the embodiments of the present application.

[0025] Reference Figure 1 As shown, the anti-thermal extrusion die provided in the embodiment of the present application includes a die sleeve 100 and a die core 200, the die sleeve 100 has a through hole extending along its own axial direction; the die core 200 is arranged in the through hole, and an extrusion channel 300 is formed between the outer wall of the die core 200 and the inner wall of the die sleeve 100, the die core 200 has a center hole 210 extending along its own axial direction, and the center hole 210 is used to allow the cable core 400 to pass through, the side of the die core 200 close to the center hole 210 is an inner annular surface 220, and the side of the die core 200 away from the center hole 210 is an outer annular surface 230, and an insulating cavity 240 is formed between the inner annular surface 220 and the outer annular surface 230. The inside of the insulation cavity is air, and the thermal conductivity of air is about 0.023 W / m·k, which can effectively isolate the radial temperature drop of the tube wall of the mold core 200 from the inside to the outside. In this way, the outer annular surface 230 of the mold core 200 can maintain the optimal extrusion temperature of the polymer melt as much as possible. When the molten polymer flows to this tube wall, the smooth flow of the flow channel is not affected by the temperature drop, and it can be evenly extruded onto the conductor or cable core 400. After cooling and solidification, it forms the insulation or sheath of the cable, which will not cause eccentricity of the insulation or sheath, or form holes, disconnection, etc., thereby ensuring the quality of the product.

[0026] Reference Figure 2 As shown, the extrusion end face of the core 200 is formed with an annular groove 250 which is recessed along the axial direction of the core 200, and a sealing cover 260 is provided at the notch of the annular groove 250, and the sealing cover 260 and the annular groove 250 together form an insulating cavity 240. Specifically, the depth of the annular groove 250 is greater than the axial length of the extrusion section of the core 200. In this way, the thermal insulation effect can be ensured. By providing the annular groove 250, the processing of the sealing cavity is facilitated. By providing the sealing cover 260, the molten polymer can be prevented from flowing into the annular groove 250. In some specific embodiments, a vacuum interface is provided on the sealing cover 260, and by connecting the vacuum interface to a vacuum pump, a vacuum environment is formed in the insulating cavity 240, thereby further improving the thermal insulation effect.

[0027] Reference Figure 3 , Figure 6As shown, in some embodiments, the anti-loss of temperature extrusion die further includes a uniform heat pipe 500, which is an annular tube coaxial with the core 200, and the uniform heat pipe 500 is arranged inside or on the surface of the core 200, for example, the uniform heat pipe 500 is embedded inside the core 200. For another example, a limited ring groove 251 is formed on the inner wall of the annular groove 250 close to the extrusion channel 300, and the uniform heat pipe 500 is penetrated in the limited ring groove 251. The uniform heat pipe 500 is filled with a heat-conducting medium. For example, the heat-conducting medium is heat-conducting silicone oil, which has a high thermal conductivity and can balance the temperature of the upper and lower edges of the core 200, so that the circumferential temperature of the core 200 is kept consistent, thereby ensuring that the flow rate of the polymer melt flowing through the core 200 at the same axial position and different radial positions is as consistent as possible, so that the thickness of the insulation or sheath at the same axial position and different radial positions of the cable core 400 is consistent, thereby improving the concentricity of the cable core 400 and the insulation or sheath.

[0028] Reference Figure 4 As shown, in some embodiments, the upper and lower ends of the uniform heat pipe 500 are respectively an evaporation section 510 and a condensation section 520, and a liquid wick 530 is arranged between the evaporation section 510 and the condensation section 520, that is, the left and right ends of the uniform heat pipe 500 are provided with a liquid wick 530, and the liquid wick 530 is made of a material with a capillary effect, such as a metal wire mesh, a porous ceramic, etc. For example, it is formed by sintering a metal powder or a metal wire mesh with a certain mesh number on the inner wall of the tube, and has a high capillary suction force. The heat-conducting medium filled in the uniform heat pipe 500 can be pure water, ammonia, methanol, etc.

[0029] In actual use, the evaporation section 510 is placed at the upper edge of the mold core 200, and the condensation section 520 is placed at the lower edge of the mold core 200. Due to the contact with the cable core 400 with a lower temperature, the temperature of the lower edge of the mold core 200 is lower than the temperature of the upper edge of the mold core 200. Therefore, during operation, the steam pressure of the evaporation section 510 is higher than that of the condensation section 520, and a pressure difference is formed at both ends. This pressure difference drives the heat-conducting medium vapor from the evaporation section 510 to the condensation section 520. When the vapor condenses in the condensation section 520, it releases heat, thereby increasing the temperature of the lower edge of the mold core 200. At the same time, under the capillary suction of the liquid wick 530, the heat-conducting medium flows back from the condensation section 520 to the evaporation section 510 along the liquid wick 530, completing a complete cycle and realizing cyclic operation.

[0030] Reference Figure 5As shown, in some embodiments, the uniform heat pipe 500 includes a first tube body 540 and a second tube body 540, the first tube body 540 and the second tube body 540 are arc-shaped tubes, and the first tube body 540 and the second tube body 540 have an evaporation section 510, a condensation section 520 and a liquid absorption core 530 inside. A spring 550 is arranged between the ends of the first tube body 540 and the second tube body 540, and the first tube body 540, the second tube body 540 and the spring 550 together form a closed ring, and the spring 550 can make the first tube body 540 and the second tube body 540 respectively snap into the limiting ring groove 251 by generating elastic deformation. In this way, the first tube body 540 and the second tube body 540 are pushed axially from the notch of the annular groove 250 until they reach the limiting ring groove 251. Under the elastic force of the spring 550, the first tube body 540 and the second tube body 540 will automatically snap into the limiting ring groove 251, thereby achieving quick installation.

[0031] Reference Figure 7 , Figure 8 As shown, the anti-loss of temperature extrusion die also includes a heat conductive sheet 600, which is evenly arranged in the extrusion channel 300 along the circumferential direction, and has an inner edge 610 and an outer edge 620 arranged opposite to each other, the inner edge 610 is connected to the outer wall of the mold core 200, and the outer edge 620 is connected to the inner wall of the mold sleeve 100. The heat conductive sheet 600 is made of a material with a high thermal conductivity coefficient, and the temperature of the mold core 200 and the mold sleeve 100 can be further balanced by the heat conductive sheet 600, so as to avoid holes and disconnection caused by the temperature of the mold core 200 being lower than that of the mold sleeve 100.

[0032] Specifically, refer to Fig. 9 As shown, when the temperature of the mold core 200 is lower than the temperature of the mold sleeve 100, the extrusion speed of the polymer melt near the mold core 200 is lower than the extrusion speed of the polymer melt near the mold sleeve 100, thereby forming holes and disconnection between the mold core 200 and the cable core 400, as shown in FIG. Fig.10 By arranging the heat conductive sheet 600 in the extrusion channel 300, the inner edge 610 of the heat conductive sheet 600 is connected to the outer wall of the mold core 200, and the outer edge 620 of the heat conductive sheet 600 is connected to the inner wall of the mold sleeve 100, so that the temperature of the mold core 200 and the mold sleeve 100 can be balanced, avoiding the occurrence of holes and disconnection caused by the temperature of the mold core 200 being lower than that of the mold sleeve 100.

[0033] Specifically, the heat conductive sheet 600 has a front edge 630 and a rear edge 640, and the width of the front edge 630 gradually decreases along the extrusion direction. In this way, the polymer melt that flows through the heat conductive sheet 600 and is separated by the heat conductive sheet 600 can be quickly accumulated to ensure the degree of fusion. Figure 7 As shown, the front side of the heat conductive sheet 600 is formed with a tip protruding forward. Figure 7As shown, the front side of the heat conductive sheet 600 is formed with an arc-shaped end protruding forward.

[0034] A plastic extruder is also provided in an embodiment of the present application, comprising the anti-loss of temperature extrusion die in the above embodiment.

[0035] It should be noted that the plastic extruder includes an anti-loss of temperature extrusion die, which also includes all the advantages of the anti-loss of temperature extrusion die mentioned above, which will not be repeated here.

[0036] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0037] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0038] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0039] In the present application, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0040] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. An anti-loss of temperature extrusion die, characterized in that: include: A mold sleeve, wherein the mold sleeve has a through hole penetrating along the axial direction of the mold sleeve; A mold core is arranged in the through hole, an extrusion channel is formed between the outer wall of the mold core and the inner wall of the mold sleeve, the mold core has a center hole penetrating along its own axial direction, the center hole is used to allow the cable core to pass through, the side of the mold core close to the center hole is an inner annular surface, the side of the mold core away from the center hole is an outer annular surface, and an insulating cavity is formed between the inner annular surface and the outer annular surface.

2. The anti-loss of temperature extrusion die according to claim 1, characterized in that: The extrusion end surface of the mold core is formed with an annular groove recessed along the axial direction of the mold core, and a sealing cover is arranged at the notch of the annular groove, and the sealing cover and the annular groove together form the heat insulation cavity.

3. The anti-loss of temperature extrusion die according to claim 2, characterized in that: The depth of the annular groove is greater than the axial length of the extrusion section of the mold core.

4. The anti-loss of temperature extrusion die according to claim 3, characterized in that: It also includes a heat-distributing pipe, which is an annular pipe coaxial with the mold core and is arranged inside or on the surface of the mold core. The heat-distributing pipe is filled with a heat-conducting medium.

5. The anti-loss of temperature extrusion die according to claim 4, characterized in that: The two opposite ends of the heat-dissipating pipe are respectively an evaporation section and a condensation section, and a liquid absorption core is arranged between the evaporation section and the condensation section.

6. The anti-loss of temperature extrusion die according to claim 5, characterized in that: A limiting annular groove is formed on the inner wall of the annular groove close to the extrusion channel, and the heat-distributing pipe is inserted into the limiting annular groove.

7. The anti-loss of temperature extrusion die according to claim 6, characterized in that: The heat-dissipating pipe includes a first tube body and a second tube body, the first tube body and the second tube body are respectively arc-shaped tubes, a spring is arranged between the ends of the first tube body and the second tube body, the first tube body, the second tube body and the spring together form a closed ring, and the spring can make the first tube body and the second tube body respectively snap into the limiting ring groove by generating elastic deformation.

8. The anti-temperature loss extrusion die according to any one of claims 1 to 7, characterized in that: It also includes a heat conductive sheet, which is evenly arranged in the extrusion channel along the circumferential direction, and has an inner edge and an outer edge that are relatively arranged, the inner edge is connected to the outer wall of the mold core, and the outer edge is connected to the inner wall of the mold sleeve.

9. The anti-loss of temperature extrusion die according to claim 8, characterized in that: The heat conducting sheet has a front side edge and a rear side edge, and the width of the front side edge gradually decreases along the extrusion direction.

10. A plastic extruder, characterized in that: The invention comprises the anti-temperature loss extrusion die as described in any one of claims 1 to 9.

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