A railway locomotive cable outer jacket extrusion assembly and method

Abstract

The application discloses a railway locomotive cable outer sheath extrusion assembly and belongs to the technical field of cable manufacturing. The railway locomotive cable outer sheath extrusion assembly comprises a first extruder, a cooling mechanism and a second extruder through which a cable passes in sequence, the first extruder is used for extruding a first sheath layer to the cable, the second extruder is used for extruding a second sheath layer to the outside of the first sheath layer, the cooling mechanism comprises a water collecting tank, a spraying chamber, a blowing chamber and a drying chamber arranged at the tank opening of the water collecting tank, the spraying chamber is used for spraying cooling water to the first sheath layer, the blowing chamber is used for blowing off water drops on the surface of the first sheath layer, the spraying chamber and the blowing chamber are arranged alternately, and the drying chamber is provided with a third cylindrical passage, second blowing heads are spirally arranged in the inner circumferences of the third cylindrical passage, and the second blowing heads are used for drying the first sheath layer. The application further provides a railway locomotive cable outer sheath extrusion method. The PE sheath layer and the low-smoke halogen-free flame-retardant oil-resistant layer are extruded in one time by using the extrusion assembly in a continuous co-extrusion mode, so that the cable has good roundness.

Description

Technical Field

[0001] This invention belongs to the field of cable manufacturing technology, and specifically relates to an extrusion assembly and method for the outer sheath of railway locomotive cables. Background Technology

[0002] Because the sheathing materials used in locomotive cables are mostly low-smoke halogen-free flame-retardant and oil-resistant materials, these materials have poor fluidity. Using extrusion molds results in a rough sheath surface and a tendency for adhesive breakage during production. Semi-extrusion molds can solve the breakage problem, but after multi-core cables are bundled, gaps remain between the cores, and the sheath is not perfectly round. Insufficient pressure during semi-extrusion mold production leads to an inadequate bond between the sheath and the cable core, resulting in an uneven outer sheath that fails to meet customer requirements. Extrusion molds solve these problems. During production, the material is pressed under high pressure onto the cable core using a mold, and then extruded into round sheaths through a die sleeve. The sheath is tightly bonded to the inner layer, resulting in a smooth and round cable appearance. However, because locomotive cable cores are mostly tin-plated braided shielded cores, certain applications require a double composite shielding mode of aluminum foil and tin-plated copper wire to prevent high and low frequency electromagnetic interference. The braided layer and inner layer have low friction, and extrusion molds present the following problems: 1. When the extrusion pressure of the mold is large, the surface of the sheath is round, but the extrusion of the plastic will cause the braided layer to shrink and accumulate. During the production process, the yarn needs to be cut into sections frequently, which cannot meet the production needs of large lengths, resulting in material waste and failure to guarantee the appearance quality. 2. When the extrusion pressure of the die is too low, the surface of the sheath is not round. In order to ensure a round appearance, the thickness of the outer sheath needs to be increased by 0.3-0.5mm on the basis of meeting the standard maximum outer diameter, so that more plastic fills the gaps between the cable core and the braiding gaps, resulting in a lot of material waste. 3. If the braided yarn is fixed by means of strapping, the plastic will be squeezed backward during the production process, causing the strapping to shrink and accumulate, which still cannot meet the production requirements.

[0003] 4. Existing cooling equipment only cools the cables by spraying, which has low cooling efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a railway locomotive cable outer sheath extrusion assembly and method, aiming to solve the problems existing in the prior art mentioned above.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A railway locomotive cable outer sheath extrusion assembly includes a first extruder, a cooling mechanism, and a second extruder through which the cable passes in sequence. The first extruder extrudes a first sheath layer onto the cable through a tube-type die, and the second extruder extrudes a second sheath layer onto the outside of the first sheath layer through a compression die. The cooling mechanism includes a water collection tank, and a spray chamber, a blowing chamber, and a drying chamber disposed at the opening of the water collection tank. The spray chamber is used to spray cooling water onto the first sheath layer, and the blowing chamber is used to quickly blow off cooling water droplets from the surface of the first sheath layer. The spray chamber and the blowing chamber are alternately arranged. The drying chamber is provided with a third cylindrical channel through which the cable passes. A second blowing head is evenly spirally arranged in the inner circumference of the third cylindrical channel and faces the cable. The second blowing head is used to dry the first sheath layer. The first extruder is equipped with a vacuum device.

[0006] Furthermore, the spray chamber is provided with a first cylindrical channel through which the cable passes, and spray heads facing the cable are evenly arranged circumferentially inside the first cylindrical channel. The blow chamber is provided with a second cylindrical channel through which the cable passes, and first blow heads facing the cable are evenly arranged circumferentially inside the second cylindrical channel.

[0007] Furthermore, the water collection tank is connected to the drying chamber via a connecting part. The drying chamber and the connecting part are rotatably engaged. The drying chamber has a cylindrical structure and is fitted with a gear ring. The connecting part is equipped with a drive motor. The output end of the drive motor is equipped with a gear. The gear meshes with the gear ring. The drying chamber and the connecting part are respectively hollow structures. The drying chamber is connected to the connecting part. The connecting part is equipped with a third air inlet connector for connecting to external air supply.

[0008] Furthermore, the bottom of the first cylindrical channel and the second cylindrical channel are respectively provided with drainage channels for connecting the water collection tank.

[0009] A method for extruding the outer sheath of a railway locomotive cable, the method using the aforementioned railway locomotive cable outer sheath extrusion assembly, includes the following steps: Step 1: The first extruder extrudes the PE sheath into the outer layer of the cable through an extrusion die; Step two: The cooling mechanism rapidly cools the PE sheath, causing it to shrink and form wrinkles to increase adhesion. Step 3: The second extruder extrudes a low-smoke, halogen-free, flame-retardant, and oil-resistant layer onto the PE sheath through an extrusion die.

[0010] Furthermore, the extrusion die includes a long nozzle die core and a first die sleeve, with the port of the long nozzle die core extending 1-2mm beyond the end of the wire receiving port of the first die sleeve.

[0011] Furthermore, the extrusion die includes a nozzleless die core and a second die sleeve, and the distance between the port of the nozzleless die core and the end of the wire-bearing port of the second die sleeve is 5-7mm.

[0012] Furthermore, the thickness of the PE layer is 0.2-0.3 mm.

[0013] Compared with the shortcomings and deficiencies of existing technologies, the present invention has the following beneficial effects: 1. This invention provides an extrusion assembly for the outer sheath of railway locomotive cables, comprising a first extruder, a cooling mechanism, and a second extruder. The first extruder uses a tube-type die to extrude a first sheath layer made of PE material. In the cooling mechanism, a spray chamber sprays cooling water onto the first sheath layer, rapidly reducing its temperature and causing wrinkles. A blowing chamber blows water onto the first sheath layer, removing water droplets from its surface. Through alternating spraying and blowing, the first sheath layer is rapidly cooled, reducing residual water at the wrinkles. Finally, in a drying chamber, a second blower sprays water from multiple angles onto the first sheath layer. The first sheath is fully dried. The second extruder uses an extrusion die to extrude the second sheath to the outside of the first sheath. The second sheath is made of low-smoke, halogen-free, flame-retardant, and oil-resistant material. Compared with existing extrusion equipment, this railway locomotive cable outer sheath extrusion assembly adopts a continuous co-extrusion method. The first sheath is set to avoid the shrinkage and accumulation of the cable braid. The cooling mechanism makes the first sheath cool down and wrinkle quickly. The wrinkles help increase the adhesion between the first and second sheaths, making it less prone to delamination. This is beneficial for the production of larger lengths. At the same time, the cable has good roundness and less material waste.

[0014] 2. The drive motor drives the drying chamber to rotate through the transmission structure of the size and rack and pinion, and works with the spirally arranged second spray head to rotate and spray the surface of the first protective layer, which is conducive to the thorough drying of the first protective layer. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of an extrusion assembly for the outer sheath of a railway locomotive cable in this invention.

[0016] Figure 2 This is a schematic diagram of the cooling mechanism in this invention.

[0017] Figure 3 This is a cross-sectional structural diagram of the cooling mechanism in this invention.

[0018] Figure 4 This is a schematic diagram of the structure of the spray chamber and the water collection tank in this invention.

[0019] Figure 5 This is a schematic diagram of the structure of the jetting chamber and the water collection tank in this invention.

[0020] Figure 6 This is a cross-sectional structural diagram of the drying chamber in this invention.

[0021] Figure 7 This is a schematic diagram of the structure of the drying chamber and the water collection tank in this invention.

[0022] Figure 8 This is a schematic diagram of the connection structure between the spray chamber and the drying chamber in this invention.

[0023] Figure 9 This is a schematic diagram of the structure of the long-nozzle mold core and the first mold sleeve in this invention.

[0024] Figure 10 yes Figure 1 A magnified schematic diagram of the structure at point A in the middle.

[0025] In the diagram: 1-First extruder; 2-Cooling mechanism; 3-Second extruder; 4-Vacuum device; 5-Long nozzle die core; 6-First die sleeve; 7-Nozzleless die core; 8-Second die sleeve; 9-Cable; 10-Water collection tank; 11-Spray chamber; 12-Blow-out chamber; 13-Drying chamber; 14-Spray head; 15-First cylindrical channel; 16-First blow-out head; 17-Second cylindrical channel; 18-Second blow-out head; 19-Third cylindrical channel; 20-Water inlet; 21-First air inlet connector; 22-Second air inlet connector; 23-First protective layer; 24-Drainage groove; 25-Gear ring; 26-Gear; 27-Connecting part; 28-Drive motor; 29-Third air inlet connector; 30-Connecting groove; 31-First threaded hole; 32-Connecting plate; 33-Second threaded hole. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0027] Reference Figure 1 A railway locomotive cable outer sheath extrusion assembly includes a first extruder 1, a cooling mechanism 2, and a second extruder 3 arranged in sequence. The first extruder 1 extrudes a first sheath 23 onto the cable, the cooling mechanism 2 rapidly cools the first sheath 23 on the outside of the cable 9, and the second extruder 3 is used to extrude a second sheath onto the outside of the first sheath 23.

[0028] A vacuum device 4 is provided on one side of the first extruder 1. The first extruder 1 is equipped with a long nozzle die core 5 and a first die sleeve 6. The port of the long nozzle die core 5 enters the first die sleeve 6 and the port of the long nozzle die core 5 slightly protrudes from the end of the wire receiving port of the first die sleeve 6 to form a tube-type structure. Preferably, the port of the long nozzle die core 5 protrudes 1-2mm from the end of the wire receiving port of the first die sleeve 6. The vacuum device 4 is connected to the end of the long nozzle die core 5. When the first extruder 1 extrudes the first sheath 23 into the cable through the long nozzle die core 5 and the first die sleeve 6, the vacuum device 4 extracts the air between the first sheath 23 and the cable 9 to eliminate the pressure when the first sheath 23 is extruded and to prevent the braided layer of the cable from shrinking and accumulating.

[0029] The second extruder 3 is equipped with a nozzleless die core 7 and a second die sleeve 8. The port of the nozzleless die core 7 is inserted into the second die sleeve 8. The port of the nozzleless die core 7 is spaced a certain distance from the wire receiving port of the second die sleeve 8 to form an extrusion structure. Preferably, the port of the nozzleless die core 7 is spaced 5-7mm from the wire receiving port of the second die sleeve 8. The second extruder 3 extrudes the second sheath to the outside of the first sheath 23 of the cable 9 through the cooperation of the nozzleless die core 7 and the second die sleeve 8.

[0030] Reference Figures 2-5 The cooling mechanism 2 includes a water collection tank 10, a spray chamber 11, and a spraying chamber 12. The spray chamber 11 and the spraying chamber 12 are alternately arranged above the opening of the water collection tank 10. Specifically, the opening of the water collection tank 10 is connected to the spray chamber 11 and the spraying chamber 12 via a mounting bracket. The mounting bracket can be a horizontally arranged mounting plate. The spray chamber 11 has a first cylindrical channel 15 for the cable 9 to pass through. The outer wall of the spray chamber 11 has a water inlet 20. Spray heads 14 are arranged circumferentially in the first cylindrical channel 15. The spray chamber 11 has a pipe for connecting the water inlet 20 and the spray heads 14. External water supply is introduced into the spray chamber 11 through the water inlet 20 and then into the spray heads 14 through the pipe. The spray heads 14 spray water towards the first protective layer outside the cable 9. The spray cooling water in layer 23 is used for rapid cooling of the first sheath 23. The spray chamber 12 has a second cylindrical channel 17 through which the cable 9 passes. A first air inlet connector 21 is located on the outside of the spray chamber 12. First spray nozzles 16 are arranged circumferentially around the second cylindrical channel 17. A pipeline connecting the first air inlet connector 21 and the first spray nozzles 16 is located inside the spray chamber 12. An air supply device introduces gas into the spray chamber 12 through the first air inlet connector 21 and delivers it to the first spray nozzles 16 through the pipeline. The first spray nozzles 16 spray gas onto the surface of the sprayed first sheath 23, blowing off water droplets and quickly removing heat from the surface of the first sheath 23, thus facilitating rapid cooling of the first sheath 23. The spray chambers 11 and 12 are arranged alternately to improve the cooling effect on the first sheath 23. The first spray nozzles 16 can adopt a duckbill structure and be positioned perpendicular to the direction of the cable 9.

[0031] Reference Figure 4 and Figure 5 The lower part of the spray chamber 11 and the blowing chamber 12 is provided with a drainage trough 24. The drainage trough 24 is used to connect the first cylindrical channel 15 and the second cylindrical channel 17 to the water collection tank 10 respectively, so as to facilitate the cooling water sprayed and blown down into the water collection tank 10.

[0032] Reference Figure 3A drying chamber 13 is provided at one end of the water collection tank 10. The drying chamber 13 is located behind the spray chamber 11 and the blowing chamber 12 in the direction of cable 9 movement, and is used to quickly dry the surface of the first sheath 23. The drying chamber 13 is provided with a third cylindrical channel 19 for the cable 9 to pass through. A second air inlet connector 22 is provided on the outer wall of the drying chamber 13. The interior of the drying chamber 13 adopts a cavity structure. A second blowing head 18 is arranged circumferentially in the third cylindrical channel 19. The end of the second blowing head 18 is connected to the cavity inside the drying chamber 13. The air supply equipment introduces gas into the cavity inside the drying chamber 13 through the second air inlet connector 22. The second blowing head 18 blows gas onto the first sheath 23 on the surface of the cable 9, thereby achieving rapid drying of the surface of the first sheath 23.

[0033] In one embodiment, refer to Figure 8 The spray chamber 11 has connecting grooves 30 on both vertical sidewalls, and the groove surface of the connecting grooves 30 has a first threaded hole 31. The spray chamber 12 has connecting plates 32 on both vertical sidewalls, and the connecting plates 32 have a second threaded hole 33. The connecting plates 32 are aligned and snapped into the connecting grooves 30. When adjacent spray chambers 11 and spray chambers 12 are connected, the connecting plates 32 are snapped into the connecting grooves 30, and the first threaded hole 31 and the second threaded hole 33 are aligned and connected. The adjacent spray chambers 11 and spray chambers 12 are connected by threaded rods. The connecting grooves 30 are set on the vertical sidewalls of the spray chamber 11, which is conducive to the alignment of adjacent spray chambers 11 and spray chambers 12, thereby aligning and connecting the first cylindrical channel 15 and the second cylindrical channel 17, which is conducive to improving the cooling effect on the first protective layer 23. The spray chambers 11 and spray chambers 12 adopt a quick assembly structure, which is conducive to improving the convenience of loading, unloading and maintenance during use.

[0034] In one embodiment, refer to Figure 6 and Figure 7The drying chamber 13 is cylindrical in shape. A connecting part 27 is rotatably connected to one side of the drying chamber 13. The connecting part 27 is located at one end of the drying chamber 13. A through hole for a cable to pass through is provided in the center of the connecting part 27. A sliding groove for the rotation of the drying chamber is provided around the through hole. The connecting part 27 has a hollow structure inside. The internal cavity of the drying chamber 13 is connected to the connecting part 27. The connecting part 27 is provided with a third air inlet connector 29. The drying chamber 13 is fixed to the water collection tank 10 through the connecting part 27. A toothed ring 25 is sleeved on the outside of the drying chamber 13. A drive motor 28 is fixed on the top of the connecting part 27. A gear 26 is provided at the output end of the drive motor 28. The gear 26 meshes with the toothed ring 25 for transmission. The second nozzle 18 is spirally arranged along the third cylindrical channel 19, and the end of the second nozzle 18 is inclined towards the axis of the third cylindrical channel 19. The drive motor 28 drives the drying chamber 13 to rotate through the transmission structure of gear 26 and gear ring 25. The air supply device supplies air to the connection part 27 through the third air inlet connector 29. The gas is introduced into the internal cavity of the drying chamber 13 through the connection part 27, and finally blows the surface of the first sheath 23 outside the cable 9 through the spiral spray head 18 to achieve the purpose of thorough drying.

[0035] The water collection tank (10) can achieve water resource recycling by connecting a filter device and a water pump. This is existing technology and will not be elaborated here.

[0036] A method for extruding the outer sheath of a railway locomotive cable, the method using the aforementioned railway locomotive cable outer sheath extrusion assembly, includes the following steps: Step 1: The first extruder 1 extrudes the PE sheath to the outer layer of the cable 9 through the extrusion die; Step 2: Cooling mechanism 2 rapidly cools the PE protective layer, causing it to shrink and form wrinkles. Step 3: The second extruder 3 extrudes a low-smoke, halogen-free, flame-retardant, and oil-resistant layer onto the PE sheath through an extrusion die.

[0037] Reference Figure 9 In step one, the vacuum device 4 works with the first extruder 1 to extrude the PE protective layer. The extrusion die adopts a combination structure of a long nozzle core 5 and a first die sleeve 6. In order to make the PE layer thickness uniform, the stretch ratio of the PE protective layer is 1.3-2.0. The outer cone angle a of the long nozzle core 5 is designed to be 52°, the inner cone angle b of the first die sleeve 6 is designed to be 55°, the length of the nozzle d1 of the long nozzle core 5 is designed to be 20mm, the length of the wire receiving port d2 of the first die sleeve 6 is designed to be 15mm, and the end of the long nozzle core 5 extends 1-2mm beyond the end of the wire receiving port of the first die sleeve 6 to ensure extrusion while reducing extrusion pressure. The thickness of the extruded PE protective layer is 0.2-0.3mm.

[0038] The vacuum device 4 is used in conjunction with the extrusion die of the first extruder 1 to avoid the problem of shrinkage and accumulation of the braided layer of the cable 9, which helps to improve the roundness of the cable 9 and meet the production requirements of the longer length of the cable 9.

[0039] In step two, the PE sheath shrinks upon rapid cooling, creating wrinkles on its surface. This process helps increase adhesion between the sheath and the low-smoke, halogen-free, flame-retardant, and oil-resistant layer. In step three, refer to Figure 10 The distance d3 between the nozzleless die core 7 port and the second die sleeve 8 wire receiving port is 5-7mm, which is conducive to the smooth extrusion of the low smoke halogen-free flame retardant and oil-resistant layer.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A railway locomotive cable outer sheath extrusion assembly, characterized in that, The system includes a first extruder (1), a cooling mechanism (2), and a second extruder (3) through which the cable (9) passes in sequence. The first extruder (1) extrudes a first sheath (23) onto the cable (9) through a tube-type die, and the second extruder (3) extrudes a second sheath onto the outside of the first sheath (23) through a compression die. The cooling mechanism (2) includes a water collection tank (10), and a spray chamber (11), a blowing chamber (12), and a drying chamber (13) disposed at the opening of the water collection tank (10). The spray chamber (11) is used for... Cooling water is sprayed onto the first protective layer (23). The spray chamber (12) is used to quickly blow off the cooling water droplets on the surface of the first protective layer (23). The spray chamber (11) and the spray chamber (12) are alternately arranged. The drying chamber (13) is provided with a third cylindrical channel (19) through which the cable (9) passes. The third cylindrical channel (19) is circumferentially and spirally arranged with a second spray head (18) facing the cable (9). The second spray head (18) is used to dry the first protective layer. The first extruder (1) is equipped with a vacuum device (4).

2. The railway locomotive cable outer sheath extrusion assembly as described in claim 1, characterized in that, The spray chamber (11) is provided with a first cylindrical channel (15) through which the cable (9) passes. Spray heads (14) facing the cable (9) are evenly arranged in the inner circumference of the first cylindrical channel (15). The spray chamber (12) is provided with a second cylindrical channel (17) through which the cable (9) passes. First spray heads (16) facing the cable (9) are evenly arranged in the inner circumference of the second cylindrical channel (17).

3. The railway locomotive cable outer sheath extrusion assembly as described in claim 1, characterized in that, The water collection tank (10) is connected to the drying chamber (13) through the connecting part (27). The drying chamber (13) and the connecting part (27) are rotatably engaged. The drying chamber (13) has a cylindrical structure and is fitted with a gear ring (25). The connecting part (27) is equipped with a drive motor (28). The output end of the drive motor (28) is equipped with a gear (26). The gear (26) meshes with the gear ring (25). The drying chamber (13) and the connecting part (27) are respectively hollow structures. The drying chamber (13) and the connecting part (27) are connected. The connecting part (27) is equipped with a third air inlet connector (29) for connecting external air supply.

4. The railway locomotive cable outer sheath extrusion assembly as described in claim 2, characterized in that, The bottom of the first cylindrical channel (15) and the second cylindrical channel (17) are respectively provided with drainage channels (24) for connecting the water collection tank (10).

5. A method for extruding the outer sheath of a railway locomotive cable, the method using the railway locomotive cable outer sheath extrusion assembly of any one of claims 1-4, comprising the following steps: Step 1: The first extruder (1) extrudes the PE sheath onto the outer layer of the cable (9) through the extrusion die; Step 2, the cooling mechanism (2) rapidly cools the PE sheath, causing it to shrink and form wrinkles to increase adhesion; Step 3: The second extruder (3) extrudes a low-smoke, halogen-free, flame-retardant, and oil-resistant layer onto the PE sheath through an extrusion die.

6. The method for extruding the outer sheath of railway locomotive cables as described in claim 5, characterized in that, The extrusion die includes a long nozzle die core (5) and a first die sleeve (6), with the port of the long nozzle die core (5) extending 1-2mm beyond the end of the wire-bearing port of the first die sleeve (6).

7. The method for extruding the outer sheath of railway locomotive cables as described in claim 5, characterized in that, The extrusion die includes a nozzleless die core (7) and a second die sleeve (8), and the distance between the port of the nozzleless die core (7) and the end of the wire-bearing port of the second die sleeve (8) is 5-7mm.

8. The method for extruding the outer sheath of railway locomotive cables as described in claim 6, characterized in that, The thickness of the PE protective layer is 0.2-0.3 mm.

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