Rodent-resistant optical cable.

Abstract

Revised September 7, 2017. What was revealed was a high-capacity optical cable for overhead lines, which may... Preserve rodent resistance and self-reliance capabilities in the total insulation (ADSS) model. Reduce the cable weight;

Description

[Correction pursuant to Rule 26, July 25, 2017] Optical cable equipped with heat shielding function

[0001] The present invention relates to an optical cable equipped with an anti-rodent function. More specifically, the present invention relates to an optical cable for high-capacity overhead lines that can minimize the weight of the cable while ensuring anti-rodent functionality and ADSS (All-dielectric self-supporting) performance.

[0002] Recently, optical cables are primarily used as communication cables, and these optical cables are also frequently installed in the form of overhead lines.

[0003] When optical cables are installed in the form of overhead lines, they are frequently damaged by rodents such as rats or squirrels. Due to the characteristic of their incisors continuously growing, if left unchecked, the teeth cannot perform their function. Furthermore, because the elongated incisors dig into the roof of the mouth, these rodents have a habit of continuously grinding their incisors to maintain their length, in addition to their feeding behavior.

[0004] When optical cables are used for processing, problems arise where the cables are damaged as squirrels or rats gnaw on them with their front teeth, so optical cables for processing require heat resistance.

[0005] Conventionally, in order to provide a heat-repellent function, methods such as wrapping steel tape inside the outer sheath of a cable were considered, or methods such as including a heat-repellent agent containing silafluofene and microencapsulated capsaicin in the cable, as disclosed in Japanese Patent Publication No. 2004-292317, were used.

[0006] However, when using steel tape, there are issues such as the need to ground the steel tape separately and increased weight when applied to overhead lines; furthermore, when power lines are laid around overhead optical cables, heat-resistant steel tape cannot be used due to electromagnetic interference; and if the cable's outer jacket contains capsaicin, there is a problem that it fails to provide continuous heat-resistant functionality throughout the cable's lifespan due to the deterioration of insecticidal components such as silafluofene or capsaicin over time.

[0007] In addition, there is a method of providing a nylon layer instead of steel tape inside the outer shell to provide heat resistance, but it was experimentally confirmed that the heat resistance performance is only about 80% of that of steel tape, so it cannot provide sufficient heat resistance.

[0008] The present invention aims to solve the problem of providing a high-capacity optical cable for overhead lines that minimizes cable weight while ensuring anti-rodent and ADSS (All-dielectric self-supporting) performance.

[0009] To solve the above problem, the present invention may provide an optical cable comprising a core including one or more optical units, a plurality of radiation members arranged to surround the core having a strip shape with a width (W) greater than the thickness (t), and an outer jacket surrounding the outside of the radiation members.

[0010] In addition, the plurality of radiation members may be transversely wound spirally along the longitudinal direction of the core, and the pitch may be 500 mm to 1000 mm.

[0011] In addition, the above-mentioned heat-repellent material may have a Mohs hardness of 5.0 or higher.

[0012] Here, the flexural modulus of the above-mentioned heat-reducing member is 4500 kgf / mm 2 It could be more than that.

[0013] In this case, the flexural strength of the above-mentioned heat-repellent member is 90 kgf / mm 2 It could be more than that.

[0014] In addition, at least one of the optical units of the core may accommodate an optical fiber and a waterproof member within a loose tube.

[0015] And, the above loose tube is made of polybutylene terephthalate or polypropylene, and the above waterproof member may be thixotropic compound jelly, waterproof yarn, or waterproof powder.

[0016] Here, the core may have a central tension line positioned in the center and an optical unit provided around the central tension line.

[0017] In addition, at least one interposition made of polyethylene or polypropylene material may be provided around the central tension line, having a size corresponding to the optical unit.

[0018] And, the central tension line may be in contact with a plurality of optical units or a plurality of intermediaries, and each optical unit or intermediary may have an outer diameter such that it can be arranged to be in contact with two adjacent optical units or intermediaries.

[0019] Here, the width of the above-mentioned heat-repellent member may be 2.0 millimeters (mm) to 3.6 millimeters (mm), and the thickness may be 0.5 millimeters (mm) to 1.5 millimeters (mm).

[0020] In this case, each of the above-mentioned heat-repellent members has a shape in which the width (W) at the center of the thickness is the largest, and when the number of the above-mentioned heat-repellent members is n and the distance from the center of the cable to the center of the thickness of the above-mentioned heat-repellent members is R, the total sum of the widths (W) of the heat-repellent members surrounding the core can satisfy 0.1 millimeters (mm) < 2π×R - n×W < 2.0 millimeters (mm).

[0021] In addition, the above-mentioned radiation-reinforcing member may be composed of fiber-reinforced plastic.

[0022] And, the above core may be wrapped with binding tape.

[0023] In addition, to solve the above problem, the present invention may provide an optical cable comprising: an ADSS (All-dielectric self-supporting cable) optical cable for overhead lines equipped with a heat-repellent function, the optical cable comprising: a central tension wire disposed in the center; at least one loose tube containing a plurality of optical fibers and a waterproof member disposed around the central tension wire; a binding member wrapping the outside of the loose tube; a plurality of flat and long heat-repellent members formed on the outside of the binding member, composed of fiber-reinforced plastic material to provide a heat-repellent function, and disposed adjacent to each other in the longitudinal direction of the cable; and an outer jacket provided on the outside of the heat-repellent members.

[0024] In addition, the width of the above-mentioned heat-repellent member may be 2.0 millimeters (mm) to 3.6 millimeters (mm), and the thickness may be 0.5 millimeters (mm) to 1.5 millimeters (mm).

[0025] Here, the fiber-reinforced plastic constituting the heat-repellent member has a Mohs hardness of 5.0 or higher and a flexural modulus of 4500 kgf / mm² 2 Ideally, the flexural strength is 90 kgf / mm 2 It could be more than that.

[0026] In addition, each of the above-mentioned heat-repellent members has a shape in which the width (W) at the center of the thickness is the largest, and when the number of the heat-repellent members is n and the distance from the center of the cable to the center of the thickness of the heat-repellent member is R, the total width (W) of the heat-repellent members surrounding the core can satisfy 0.1 millimeter (mm) < 2π×R - n×W < 2.0 millimeter (mm).

[0027] In addition, the plurality of above-mentioned radiation members are transversely wound spirally along the cable length direction, and the pitch may be 500 mm to 1000 mm.

[0028] In addition, an inner jacket may be additionally provided between the binding member and the plurality of radiation members.

[0029] The optical cable according to the present invention is equipped with a strip-shaped heat-repellent member having a width greater than its thickness, which can sufficiently prevent damage to the cable core caused by the teeth of rodents, etc.

[0030] In addition, the optical cable according to the present invention can provide a high-capacity optical cable for overhead lines by replacing the metal protective layer conventionally provided inside the optical cable with a fiber-reinforced plastic (FRP) material to provide a heat-resistant function, thereby sufficiently reducing the weight of the optical cable.

[0031] In addition, the optical cable according to the present invention can improve the tensile strength of the optical cable compared to the case where a protective layer made of metal is provided by applying fiber-reinforced plastic (FRP) material to the central tension wire and the radiation member.

[0032] In addition, since the optical cable according to the present invention does not include a metal material composition internally, it satisfies the ADSS (all dielectric self supporting) condition and can satisfy the performance requirements for an optical cable for overhead lines laid between a communication pole or a power line pole and a steel tower.

[0033] FIG. 1 shows a cross-sectional view of one embodiment of an optical cable according to the present invention.

[0034] FIG. 2 illustrates a cross-sectional view of another embodiment of an optical cable according to the present invention.

[0035] FIG. 3 illustrates a cross-sectional view of another embodiment of an optical cable according to the present invention.

[0036] Figure 4 shows a partial enlarged view of the optical cable shown in Figure 3.

[0037] FIG. 5 illustrates a cross-sectional view of another embodiment of an optical cable according to the present invention.

[0038] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosed content is thorough and complete, and to ensure that the spirit of the invention is sufficiently conveyed to those skilled in the art. Throughout the specification, the same reference numerals indicate the same components.

[0039] FIG. 1 illustrates a cross-sectional view of one embodiment of an optical cable according to the present invention, and FIG. 2 illustrates a cross-sectional view of another embodiment of an optical cable according to the present invention.

[0040] In order to provide a heat-repellent function to the optical cable, the present invention may provide an optical cable (1) comprising a core (C) including one or more optical units, a plurality of heat-repellent members (600) arranged to surround the core and having a strip shape with a width (W) greater than the thickness (t), and an outer jacket (800) that surrounds the outside of the heat-repellent members (600).

[0041] The present invention relates to an optical cable for processing, and may be equipped with a plurality of optical units (100).

[0042] A central tension wire (200) for reinforcing tensile strength may be provided in the center of the optical cable according to the present invention. The central tension wire (200) may be composed of a material such as fiber reinforced plastic (FRP) to provide sufficient tensile strength.

[0043] The optical cable illustrated in FIGS. 1 and 2 may have at least one optical unit (100) around the central tension line (200). The optical unit (100) may contain at least one optical fiber (110) inside. Generally, the optical unit (100) may use a tight buffer method and a loose tube method in which there is no empty space inside, and the optical unit (100) of the optical cable according to the embodiment of the present invention is a loose tube method because a plurality of optical fibers are accommodated in one optical unit (100) as described below.

[0044] The optical unit (100) of the optical cable illustrated in FIGS. 1 and 2 may accommodate six optical fibers (110) and a waterproof member (130) within a loose tube (150). The loose tube (150) may be made of polybutylene terephthalate or polypropylene, and the waterproof member (130) may be thixotropic compound jelly, waterproof yarn, waterproof powder, etc.

[0045] And, depending on the required communication capacity, the optical cable shown in FIG. 1 is equipped with two optical units (100) around the central tension line (200), and the optical cable shown in FIG. 2 is equipped with four optical units (100) around the central tension line (200).

[0046] Accordingly, the optical cable shown in FIG. 1 is equipped with a total of 12 optical fibers (110), and the optical cable shown in FIG. 2 may be equipped with 24 optical fibers (110).

[0047] In this case, an optical unit (100) is placed around the central tension line (200), and at least one interposition may be provided so that the cable maintains a circular shape overall.

[0048] The optical cables illustrated in FIGS. 1 and FIGS. 2 are each equipped with three and one interposition, respectively. The interposition may have a diameter corresponding to the optical unit (100) and may be made of polyethylene or polypropylene.

[0049] The above-mentioned inclusions may be configured such that their number can be increased, decreased, or omitted depending on the required communication capacity, and may not be configured with a core as in the embodiment described below.

[0050] In the embodiment illustrated in FIGS. 1 and 2, the central tension line (200) is in contact with two and four optical units (100), respectively, and is in contact with three and one intermediary. In addition, the optical units (100) or intermediaries of the embodiment illustrated in FIGS. 1 and 2 are arranged to be in contact with two adjacent optical units (100) or intermediaries, thereby minimizing the empty space inside the core, which may be composed of a central tension line (200) having a circular cross-section, an optical unit (100), and an intermediary, so as to minimize the movement of the components constituting the core.

[0051] In order for the core to be configured so that it does not move around the central tension line (200), and for the optical unit (100) having a corresponding diameter disposed around the central tension line (200) and the interposed material to be in mutual contact, it is important to appropriately determine the diameter of the central tension line (200).

[0052] In this case, when the light unit (100) and the interlayer have diameters of corresponding sizes, if the sum of the number of the light unit (100) and the interlayer is 5 or less based on 6, the diameter of the center tension line (200) must be smaller than the diameter of the light unit (100) or the interlayer, and if it is 7 or more, the diameter of the center tension line (200) must be larger than the diameter of the light unit (100) or the interlayer. Of course, the size of the center tension line (200) can be determined within a range that satisfies the contact conditions with the center tension line (200) and the contact conditions between adjacent light units (100) or interlayers.

[0053] A waterproof yarn (400) may be provided in the empty space inside the core. If the waterproof yarn (400) has absorbency, it may be composed of various materials.

[0054] The core (C) composed of the above-mentioned central tension line (200), the above-mentioned optical unit (100), and the above-mentioned intermediary may optionally be bound with a binding tape (500). The binding tape (500) may be a form of binding member for maintaining the core (C) in a circular shape overall and for leveling the mounting surface of the radiation member (600) described later, and is not limited to a binding tape.

[0055] A plurality of rodent-repellent members (600) may be arranged on the outside of the core or binding tape according to the present invention as illustrated in FIGS. 1 and 2 to surround the core. The rodent-repellent members (600) are provided to prevent damage caused by rodents.

[0056] Specifically, the above-mentioned radiation member (600) can be wound spirally along the longitudinal direction of the core on the outer surface of the core, and the pitch can be configured to be about 500 mm to 1000 mm for bending characteristics.

[0057] As shown in FIGS. 1 and 2, the radiation member (600) may be made of fiber reinforced plastic (FRP) material in which the width (w, see FIG. 4) is greater than the thickness (t, see FIG. 4).

[0058] A plurality of radiation members (600), configured in the form of a rectangular strip with a width (W) greater than the thickness (t), can be transversely wound without gaps in a spiral pattern at the same pitch on the outer surface of the core.

[0059] Conventionally, methods such as providing steel tape inside the outer jacket (800) for heat protection were used, but this increased the weight of the cable and was unsuitable for an ADSS (All-dielectric self-supporting cable) for overhead lines installed together with power lines.

[0060] ADSS (All-dielectric self-supporting cable) optical cables refer to overhead optical cables installed between communication or power line poles and towers, characterized by their ability to safely maintain their functionality even against electric induction and lightning strikes.

[0061] Experimentally, the heat-repellent member (600) applied to the optical cable according to the present invention has a Mhos hardness of 5.0 or higher and a flexural modulus of 4500 kgf / mm² to ensure sufficient heat-repellent function. 2 Above, the flexural strength is 90 kgf / mm 2 It was confirmed that it is desirable to be composed of the above non-metallic materials. When the material of the heat shield is composed of a material satisfying the above conditions, it was possible to safely protect the interior of the core by preventing damage caused by the teeth of rodents that may access the overhead line.

[0062] The optical cable according to the present invention provides sufficient heat-repellent function as such, and a heat-repellent member (600) made of fiber reinforced plastics (FRP) can be applied as the material of the heat-repellent member (600) for implementing the ADSS cable.

[0063] When fiber reinforced plastics (FRP) are used as the above-mentioned heat-repellent member (600), the Mohs hardness is 5.0 or higher and the flexural modulus is 4500 kgf / mm 2 Above, the flexural strength is 90 kgf / mm 2 All of the above requirements for non-metallic materials could be satisfied.

[0064] It is desirable that the above-mentioned heat-repellent member (600) be installed without gaps to protect the interior while maintaining the cable in a circular shape as much as possible. Accordingly, the above-mentioned heat-repellent member (600) may be configured in a flat, thin, and long shape or in a flat, long strip shape, and may be installed parallel to each other along the circumferential direction of the cable core.

[0065] In addition, each optical unit constituting the ADSS (All-dielectric self-supporting cable) optical cable for an overhead line according to the present invention can accommodate, for example, 6, 12, or 24 optical fibers (110), and can also be configured to form a high-capacity optical cable by providing these optical units in multiple layers.

[0066] In the case of the embodiment illustrated in FIGS. 1 and 2, the diameter of the entire cable is expected to be at least about 11 millimeters (mm) to a maximum of about 17 millimeters (mm). In order to reliably and completely protect the inside of the optical cable having this diameter and maintain a circular shape as much as possible, it was confirmed that the width of the shielding member (600) is 2.0 millimeters (mm) to 3.6 millimeters (mm) and the thickness is 0.5 millimeters (mm) to 1.5 millimeters (mm).

[0067] If the thickness and width are smaller, it can be easily damaged by rodent teeth, and if the thickness and width are larger, the heat resistance can be enhanced, but the diameter and weight will increase significantly for optical cables used in overhead lines.

[0068] An outer jacket (800) may be provided on the outer side of the heat layer formed by the heat member (600), and the outer jacket (800) may be made of a material such as polyethylene (PE) or high-density polyethylene (HDPE). The thickness of the outer jacket (800) may be approximately 1.2 millimeters (mm) to 2.5 millimeters (mm).

[0069] When covering the outer surface of the above-mentioned heat-resistant member (600) with an outer jacket (800), the heat-resistant member (600) can be wrapped using non-woven fabric or the like to prevent lifting and to facilitate the work.

[0070] In addition, at least one rip cord (700) for separating the outer jacket (800) during field work may be provided on the inner side of the outer jacket (800).

[0071] And, although not shown, an inner jacket may be additionally provided between the binding member and the plurality of radiation members.

[0072] The embodiments illustrated in FIGS. 1 and 2 have six optical fibers (110) identically provided within a single optical unit (100), and two and four optical units (100) provided around a central tension wire (200), with the difference being the number of inclusions. Even though the structure is such that a central tension wire (200) is provided in the center as a method of providing inclusions, the cable can be maintained in a circular shape as much as possible and the diameter of the cable can be prevented from becoming excessively thin. The optical cables illustrated in FIGS. 1 and 2 satisfy the condition that the total diameter (D1) is 11 millimeters (mm) to 12 millimeters (mm), respectively.

[0073] In addition, as described above, since the optical cable according to the present invention has both the central tension wire (200) and the heat-repellent member (600) configured in the form of fiber-reinforced plastic, it is possible to obtain the effect of improved tensile strength while reducing weight compared to conventional optical cables to which metal tape or the like is applied for heat-repellent functions.

[0074] FIG. 3 illustrates a cross-sectional view of another embodiment of an optical cable according to the present invention. Descriptions that overlap with the description with reference to FIG. 1 and FIG. 2 are omitted.

[0075] FIGS. 1 and FIGS. 2 are optical cables having 2 and 4 optical units (100) around a central tension line (200), and each optical unit (100) accommodates 6 optical fibers (110), so that a total of 12 and 24 optical fibers (110) are provided.

[0076] There is a difference in that eight optical units (100) shown in FIG. 3 are provided, and each optical unit (100) is provided with 12 optical fibers (110), so that 96 optical fibers (110) are provided, and that no intermediaries are placed around the central tension line (200), and only the optical units (100) are placed.

[0077] As described above, when the total number of light units (100) or inclusions arranged around the central tension line (200) is 7 or more based on 6, the diameter of the central tension line (200) must be larger than the diameter of the light units (100), etc. so that the central tension line (200) and the light units (100), etc. arranged around it can be closely attached without any gaps.

[0078] In the example illustrated in FIG. 3, only eight light units (100) are provided, so the diameter of the central tension line (200) must be larger than the diameter of the light unit (100) so that they can be closely attached to each other so that the empty space inside the core is minimized.

[0079] Also, unlike the center tension line (200) shown in FIG. 1 and FIG. 2, the center tension line (200) of the embodiment shown in FIG. 3 is provided with a polyethylene coating layer (230) on the outside of the fiber-reinforced plastic (210).

[0080] Therefore, if it is not possible to form a sufficient thickness of the center tension line (200) using only fiber-reinforced plastic (210), a coating layer (230) can be added to adjust the thickness of the center tension line (200) so that there is no empty space inside the core.

[0081] In addition, the above-mentioned heat-resistant member (600) may be wound spirally along the longitudinal direction of the core on the outer surface of the core to improve bending characteristics, and since the purpose is to protect the inside of the cable from damage caused by the teeth of animals such as rodents, even if the thickness is sufficiently secured and sufficient rigidity is provided, the original function of the heat-resistant member (600) cannot be achieved if the cable is not maintained in its original shape due to problems such as gaps between the heat-resistant members (600) arranged along the longitudinal direction of the core opening up or the arranged heat-resistant members (600) pushing up and twisting each other.

[0082] Accordingly, the optical cable according to the present invention needs to optimally control the spacing between the radiation members (600) disposed on the outer surface of the core.

[0083] As described above, the radiation member (600) is preferably determined to have a width of 2.0 millimeters (mm) to 3.6 millimeters (mm) and a thickness of 0.5 millimeters (mm) to 1.5 millimeters (mm), and the number of radiation members (600) installed in the cross-sectional direction should be determined according to the capacity of the cable, that is, the number of optical units (100) or the number of optical fibers (110) accommodated in one optical unit (100).

[0084] Figure 4 shows a partial enlarged view of the optical cable shown in Figure 3.

[0085] The above-mentioned fire-resistant member (600) may have a shape closer to a flat square with somewhat rounded sides rather than a perfectly square shape, as shown in FIG. 4.

[0086] Therefore, the width of the radiation member (600) becomes largest near the center of the thickness. When the distance from the center of the optical cable to the center of the thickness direction of the radiation member (600) where the thickness of the radiation member (600) is maximum is R, and the width of the radiation member (600) that is maximum at that time is w, the number of radiation members (600) n that must be placed on the outer surface of the core was experimentally determined to be as follows.

[0087] When the number of the above-mentioned heat-repellent members (600) is n, and the distance from the center of the cable to the center of the thickness of the heat-repellent members (600) is R, the total width (W) of the heat-repellent members (600) surrounding the core must satisfy 0.1 millimeter (mm) < 2π×R - n×W < 2.0 millimeter (mm).

[0088] Here, 2π×R is the length of the circumference of a circle penetrating the center of the thickness direction of the radiation member (600), with a radius of R, and n×W is the sum of the widths of each radiation member (600).

[0089] And, when the width of the radiation member (600) is sufficiently small, it can be assumed that the length of the arc passing through the center of the thickness direction of the radiation member (600) and the width of the radiation member (600) penetrating the center of the thickness direction of the radiation member (600) are almost the same size, and 2π×R - n×W can be assumed to be the sum of the spacing (g) between the center points of the thickness direction of each radiation member (600).

[0090] It was experimentally confirmed that the total gap between the heat shield members (600) must be smaller than 2.0 millimeters (mm) to sufficiently protect the inside of the core so that the teeth of rodents, etc., which can access the optical cable laid on the overhead line cannot penetrate, and that the gap must be at least 0.1 millimeters (mm) so that problems such as the heat shield members (600) being pushed and twisted against each other do not occur and the cable can be maintained in a circular shape as much as possible.

[0091] That is, since the width of the desired heat-repellent member (600) is 2.0 millimeters (mm) to 3.6 millimeters (mm) as described above, if the value of 2π×R - n×W is 3.8 millimeters (mm), it means that the heat-repellent member (600) is insufficient and therefore one more heat-repellent member (600) must be added.

[0092] In addition, if the value of 2π×R - n×W is 0.05 millimeters (mm), it means that even if a slight impact or bending is applied to the cable, the cable will be twisted and deformed, making it difficult to maintain its original shape. If removing one of the heat-resistant members (600) does not satisfy the above range again, it may mean that it is preferable to apply a heat-resistant member (600) with a slightly smaller width in the range of 2.0 millimeters (mm) to 3.6 millimeters (mm).

[0093] And, it was confirmed that the optical cable shown in FIGS. 3 and 4 has a total cable diameter (D2) of only about 13 millimeters (mm) to 14 millimeters (mm) even when accommodating 96 optical fibers (110) in a loose tube manner.

[0094] FIG. 5 illustrates a cross-sectional view of another embodiment of an optical cable according to the present invention. Descriptions that overlap with the descriptions with reference to FIG. 1 to 4 are omitted.

[0095] The embodiment illustrated in FIG. 5 is provided with 12 optical units (100) in the form of loose tubes without interposition around the central tension line (200), and 12 optical fibers (110) are provided inside each optical unit (100), so that a total of 144 optical fibers (110) are provided, enabling high-capacity optical communication.

[0096] In addition, the central tension line (200) and the light unit (100) are in contact with each other, and each light unit (100) is in contact with two adjacent light units (100), so that the internal empty space is minimized, and it can be confirmed that the diameter of the central tension line (200) is larger than the diameter of the light unit (100).

[0097] In addition, it can be confirmed that the optical cable shown in Fig. 5 can be laid for overhead lines with an overall cable diameter (D3) of about 16 millimeters (mm) to 17 millimeters (mm), and can satisfy all conditions including sufficient heat resistance, ADSS (All-dielectric self-supporting), and weight requirements even without an internal metal structure.

[0098] Although this specification has been described with reference to preferred embodiments of the present invention, those skilled in the art may modify and change the present invention in various ways without departing from the spirit and scope of the present invention as described in the claims below. Therefore, if a modified embodiment basically includes the components of the claims of the present invention, it should be considered to be included within the technical scope of the present invention.

Claims

Revised September 7, 2017 1. An optical cable comprises: a core containing one or more optical units; more than one rodent-resistant component formed into a strip shape, with its width greater than its thickness, and enclosed around the core; and an outer jacket customized to enclose the outer surface of the rodent-resistant component.