Vertical production method for insulating layer of leaky coaxial cable

Abstract

The invention relates to the technical field of leaky coaxial cable production, in particular to a leaky coaxial cable insulating layer vertical production method, which comprises the following steps: S1, paying off by paying-off equipment, guiding a conductor into wire storage equipment by a lower wire guide wheel and an upper wire guide wheel to enter an upper traction device, and guiding the conductor to a straightening device by traction to be straightened; s2, the foaming insulation layer penetrates through a machine head of the plastic extruding machine set in the vertical direction, so that the foaming insulation layer is formed on the outer surface of the inner conductor; and S3, after the foaming insulating layer is formed, the foaming insulating layer penetrates through the cooling pipe in the vertical direction, passes through the lower wire guide wheel and is finally wound on the take-up equipment. According to the vertical production method for the insulating layer of the leaky coaxial cable, the foaming insulating layer adopts a vertical production mode, so that the problems of foaming holes, hole stringing, out-of-round and eccentricity of the foaming insulating layer caused by gravity in the horizontal production process of the foaming insulating layer are avoided; and meanwhile, the vertical production mode keeps the roundness of the foaming insulating layer because the foaming insulating layer still keeps cylindrical downward movement along with traction during extrusion.

Description

Technical Field

[0001] The invention relates to the technical field of leaky coaxial cable production, in particular to a vertical production method for the insulation layer of a leaky coaxial cable. Background Art

[0002] Leaky coaxial cable products are insulated with PE foam (density 0.20g / cm 3 ) process, the high foaming degree can reach more than 80%. The wall thickness of the foamed insulation of general products is 2-20mm, and the wall thickness of the foamed insulation of special specifications is >20mm. When extruded at a temperature of 180°, the melt support strength of the high foamed PE material is low, which is insufficient to support the weight of the foamed insulation, and the foamed insulation layer is out of round, making molding difficult; when the horizontal cooling production method is adopted, due to the low density, the buoyancy of the insulation in the water is very large, and the upper and lower layers of the foamed insulation layer are subjected to different forces in the horizontal state, which makes it easy for bubbles, strings of holes, and out of roundness to appear at the inner conductor.

[0003] Ordinary cable products are all insulated with solid insulation (taking solid PE as an example, the density is 0.95g / cm 3 ), the insulation wall thickness is mostly within 0.01-10mm. The extrusion production method of this type of insulation is a horizontal production line method, and horizontal circulating cooling water is used for cooling; because the insulation is solid and the wall thickness is small, extrusion and cooling have little effect on the quality of the insulation product. Summary of the invention

[0004] The technical problem to be solved by the present invention is: in order to solve the technical problems in the prior art, the present invention provides a vertical production method for the insulation layer of a leaky coaxial cable. When the insulation thickness of high-voltage and ultra-high-voltage cables is greater than 20 mm, the vertical tower is used to extrude the insulation vertically to prevent the molding out-of-roundness that is easy to occur during insulation extrusion. When the large-size thickness is greater than 20 mm, the foamed insulation layer is easily cooled insufficiently during the horizontal cooling process, resulting in foaming layer pores, string holes, out-of-roundness, eccentricity and other problems. The vertical nitrogen pipe protection cooling system ensures that the foaming layer pores, string holes, out-of-roundness and eccentricity problems that are easy to occur when the foamed insulation is thicker than 20 mm are not cooled sufficiently.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a vertical production method for the insulation layer of a leaky coaxial cable, comprising the following steps: S1, a wire-paying device pays out the wire, and the conductor enters the wire storage device and is guided by the lower wire wheel and the upper wire wheel into the upper traction device, and is guided by traction to the straightening device for straightening; S2, the conductor passes through the head of the extrusion unit in a vertical direction, so that the foamed insulation layer is formed on the outer surface of the inner conductor; S3, after the foamed insulation layer is formed, the foamed insulation layer passes through the cooling tube in a vertical direction, passes through the lower wire wheel, and is finally rolled up on the wire-taking device.

[0006] The invention discloses a vertical production method for the insulation layer of a leaky coaxial cable. The foamed insulation layer is produced in a vertical manner, thereby avoiding the problems of foam holes, string holes, loss of roundness and eccentricity of the foamed insulation layer caused by gravity during the horizontal production process. At the same time, the vertical production method maintains the roundness of the foamed insulation layer because the foamed insulation layer remains cylindrical and moves downward with traction during extrusion.

[0007] Furthermore, a nitrogen cooling protection tube is provided at the rear end of the extruder unit, and low-temperature nitrogen is contained in the nitrogen cooling protection tube. After the foamed insulating layer is formed, it first passes through the nitrogen cooling protection tube and then enters the cooling tube.

[0008] Furthermore, the temperature of the low-temperature nitrogen is 0 to 15°C.

[0009] Furthermore, cooling water mist is provided in the cooling pipe, and the temperature of the cooling water mist is 10 to 15° C. The foamed insulation layer is gradually shaped by step-by-step cooling of low-temperature nitrogen and cooling water mist.

[0010] Furthermore, the ratio of the length of the nitrogen cooling protection tube to the length of the cooling tube is 1:5.

[0011] Furthermore, the front section of the nitrogen cooling protection tube is provided with an outer diameter and eccentricity testing device.

[0012] Furthermore, a lower traction device is provided at the rear end of the lower wire wheel; and an auxiliary traction device is provided at the rear end of the pay-off frame.

[0013] Furthermore, a circulating water pool is provided below the cooling pipe, a delivery pump is connected to the circulating water pool, an output end of the delivery pump is connected to a mixing chamber, an output end of the mixing chamber is connected to the cooling pipe, and a high-pressure air pipe is also connected to the mixing chamber.

[0014] Furthermore, a capacitance testing device is provided at the rear section of the cooling pipe.

[0015] The beneficial effects of the present invention are:

[0016] 1. The foam insulation layer adopts a vertical production method, which avoids the foaming holes, string holes, out-of-roundness and eccentricity of the foam insulation layer caused by gravity during the horizontal production process. At the same time, the vertical production method maintains the roundness of the insulation layer because the foam insulation remains cylindrical and moves downward with traction during extrusion;

[0017] 2. During cooling, the foamed insulation layer is first cooled by low-temperature nitrogen. The large temperature difference and relatively small specific heat capacity of nitrogen are used to achieve rapid cooling of the foamed insulation layer in a short nitrogen cooling protection tube. At the same time, the foamed insulation layer is prevented from directly contacting with the cooling water mist after being extruded from the die head of the extruder, which may cause the surface of the foamed insulation layer to shrink too much. Then, in the long cooling tube, the cooling water mist is used to fully contact with the foamed insulation layer for sufficient cooling. The foamed insulation layer is gradually shaped through step-by-step cooling of the low-temperature nitrogen and the cooling water mist, thereby ensuring product performance.

[0018] 3. During the vertical cooling process in the nitrogen cooling protection tube, the entire cable is not affected by buoyancy, thus avoiding the occurrence of foaming holes and string holes in the foaming layer caused by uneven cooling;

[0019] 4. The use of low-temperature nitrogen and spray cooling can effectively control the temperature in the cooling system, accelerate the foam insulation cooling effect, and improve efficiency and product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0021] Figure 1 The present invention is a flowchart of a vertical production method of a leaky coaxial cable insulation layer.

[0022] Figure 2 It is a schematic diagram of the overall structure of a vertical production device for the insulation layer of a leaky coaxial cable in the present invention.

[0023] In the figure: 1. wire-releasing equipment; 2. wire-storing equipment; 3. lower wire pulley; 4. upper wire pulley; 5. upper traction device; 6. straightening device; 7. extrusion unit; 8. outer diameter and eccentricity testing equipment; 9. nitrogen cooling protection tube; 10. first cooling tube; 11. second cooling tube; 12. third cooling tube; 121. capacitance testing equipment; 13. circulating water pool; 14. lower wire pulley; 15. traction equipment; 16. wire-receiving equipment; 17. auxiliary traction device. DETAILED DESCRIPTION

[0024] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0025] In the description of the present invention, 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 positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more. In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" 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 or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a connection between the two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] The invention discloses a vertical production method for an insulating layer of a leaky coaxial cable.

[0027] Reference Figure 1 and Figure 2 A method for producing a leaky coaxial cable insulation layer vertically comprises the following steps:

[0028] S1. The wire-paying device 1 pays off the wire. The conductor first passes through the wire storage device 2 and enters the auxiliary traction device 17. It is guided by the lower wire pulley and the upper wire pulley 4 to enter the upper traction device 5. The upper traction device 5 guides it to the straightening device 6 for straightening.

[0029] S2. After the conductor passes through the straightening device 6, it passes through the head of the extruder unit 7 in the vertical direction, so that the foamed insulation layer is formed on the outer surface of the inner conductor.

[0030] S3. After the foamed insulation layer is formed, the foamed insulation layer first passes through the nitrogen cooling protection tube 9 in the vertical direction, then passes through the cooling tube, passes through the lower wire wheel and the traction device 15, and finally is wound on the winding device 16. The nitrogen cooling protection tube 9 contains low-temperature nitrogen, and the cooling tube is provided with cooling water mist. During cooling, the foamed insulation layer is first cooled by low-temperature nitrogen, and the large temperature difference and the relatively small specific heat capacity of nitrogen are used to achieve rapid cooling of the foamed insulation layer in the shorter nitrogen cooling protection tube 9, while avoiding the possibility that the foamed insulation layer directly contacts the cooling water mist after being extruded from the head of the extruder unit 7, resulting in excessive shrinkage of the surface of the foamed insulation layer. Then, in the cooling tube with a longer length, the cooling water mist is allowed to fully contact with the foamed insulation layer for sufficient cooling. The foamed insulation layer is gradually shaped by the step-by-step cooling of the low-temperature nitrogen and the cooling water mist, thereby ensuring product performance. The use of low-temperature nitrogen and spray cooling can well control the temperature in the cooling system, accelerate the cooling effect of the foamed insulation layer, and improve efficiency and product quality. During the vertical cooling process in the nitrogen cooling protection tube 9, the entire cable is not affected by buoyancy, thus avoiding the formation of bubbles and holes in the foaming layer due to uneven cooling.

[0031] The front section of the nitrogen cooling protection tube 9 is provided with an outer diameter and eccentricity testing device 8, which is used to check the eccentricity of the foamed insulation layer, fine-tune the eccentricity of the extruder unit 7, and control the product quality. The cooling tube includes a first cooling tube 10, a second cooling tube 11, and a third cooling tube 12 arranged in sequence, and the third cooling tube 12 is installed with a capacitance testing device 121, which is used to check the foaming index of the foamed insulation layer, and fine-tune the foaming steam injection process to adjust the foaming degree.

[0032] A circulating water pool 13 is provided below the cooling pipe, and a delivery pump is connected to the circulating water pool 13. The output end of the delivery pump is connected to a mixing cabin, and the output end of the mixing cabin is connected to the first cooling pipe 10. The mixing cabin is also connected to a high-pressure air pipe, and the end of the high-pressure air pipe away from the mixing cabin is connected to an air compressor. High-pressure gas is input through the high-pressure air pipe, and cooling water is input through the delivery pump, and finally cooling water mist is formed in the mixing cabin and finally sprayed into the cooling pipe.

[0033] Working principle: The insulation layer is produced vertically, which avoids the foaming holes, string holes, out-of-roundness and eccentricity of the foamed insulation layer caused by gravity during the horizontal production process. At the same time, the vertical production method maintains the roundness of the foamed insulation layer because the foamed insulation layer remains cylindrical and moves downward with traction during extrusion.

[0034] During cooling, the foamed insulation layer is first cooled by low-temperature nitrogen, and the large temperature difference and the relatively small specific heat capacity of nitrogen are used to achieve rapid cooling of the foamed insulation layer in the shorter nitrogen cooling protection tube 9, while avoiding the possibility that the foamed insulation layer directly contacts the cooling water mist after being extruded from the head of the extruder unit 7, which may cause the surface of the foamed insulation layer to shrink too much. Then, in the longer cooling tube, the cooling water mist is allowed to fully contact the foamed insulation layer for sufficient cooling. The foamed insulation layer is gradually shaped by the step-by-step cooling of the low-temperature nitrogen and the cooling water mist, thereby ensuring product performance. The use of low-temperature nitrogen and spray cooling can well control the temperature in the cooling system, accelerate the cooling effect of the foamed insulation layer, and improve efficiency and product quality. In the vertical cooling process in the nitrogen cooling protection tube 9, the entire cable is not affected by buoyancy, which avoids the foaming layer pores and string holes caused by uneven cooling.

[0035] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A method for vertically producing the insulation layer of a leaky coaxial cable, characterized in that: The steps include: S1, the wire-paying device (1) pays off the wire, and the conductor enters the wire storage device (2) and is guided by the lower wire pulley (3) and the upper wire pulley (4) to enter the upper traction device (5), and the upper traction device (5) guides the conductor to the straightening device (6) for straightening; S2, the conductor passes through the head of the extruder unit (7) in the vertical direction, so that the foamed insulation layer is formed on the outer surface of the conductor; S3. After the foamed insulation layer is formed, the foamed insulation layer passes through the cooling pipe in a vertical direction, passes through the lower wire wheel (14), the traction device (15), and is finally rolled up on the wire-receiving device (16).

2. A method for vertically producing the insulation layer of a leaky coaxial cable according to claim 1, characterized in that: A nitrogen cooling protection tube (9) is provided at the rear end of the extruder unit (7). Low-temperature nitrogen is contained in the nitrogen cooling protection tube (9). After the foamed insulating layer is formed, it first passes through the nitrogen cooling protection tube (9) and then enters the cooling tube.

3. A method for vertically producing the insulation layer of a leaky coaxial cable according to claim 1, characterized in that: The temperature of the low temperature nitrogen is 0 to 15°C.

4. A method for vertically producing the insulation layer of a leaky coaxial cable according to claim 3, characterized in that: The cooling pipe is provided with cooling water mist, the temperature of which is 10 to 15° C. The foamed insulation layer is gradually shaped by step-by-step cooling of low-temperature nitrogen and cooling water mist.

5. A method for vertically producing the insulation layer of a leaky coaxial cable as claimed in claim 3, characterized in that: The ratio of the length of the nitrogen cooling protection tube (9) to the cooling tube is 1:

5.

6. A method for vertically producing the insulation layer of a leaky coaxial cable as claimed in claim 5, characterized in that: The front section of the nitrogen cooling protection tube (9) is provided with an outer diameter and eccentricity testing device (8).

7. A method for vertically producing the insulation layer of a leaky coaxial cable according to claim 7, characterized in that: The rear end of the wire-releasing device (1) is provided with an auxiliary traction device (17); the rear end of the lower wire wheel (14) is provided with a traction device (15).

8. A method for vertically producing the insulation layer of a leaky coaxial cable as claimed in claim 4, characterized in that: A circulating water pool (13) is provided below the cooling pipe, a delivery pump is connected to the circulating water pool (13), an output end of the delivery pump is connected to a mixing chamber, an output end of the mixing chamber is connected to the cooling pipe, and a high-pressure air pipe is also connected to the mixing chamber.

9. A method for vertically producing the insulation layer of a leaky coaxial cable as claimed in claim 2, characterized in that: The rear section of the cooling pipe is provided with a capacitance testing device (121).

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