Intrinsic safety cable and preparation method thereof

Abstract

The invention relates to an intrinsic safety cable and a preparation method thereof. The intrinsic safety cable comprises a filling core structure, a plurality of insulating core structures, a protection structure, a shielding structure, an interference structure and a sheath structure. The intrinsic safety cable has the advantages that compared with an intrinsic safety cable in the prior art, the intrinsic safety cable has the safety performance of cold resistance, high temperature resistance, oil resistance, static electricity prevention, non-flammable performance, non-explosive performance, static electricity prevention, interference resistance and the like, and further has the advantages of low capacitance, low inductance and high reliability, and therefore the comprehensive requirement for automation of the industrial process is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wire and cable manufacturing, and relates to an intrinsically safe cable and a preparation method thereof. BACKGROUND

[0002] With the continuous iteration and upgrading of global industrial automation technology, the intelligentization and networking transformation process of industrial production field is accelerating, and the layout of power supply system, control system and information transmission system in the production area is increasingly dense. The signal interaction and energy transmission between various systems are more and more frequent, and the performance of the cable products connecting the systems is required to be more stringent. Especially in the key industrial fields such as petroleum, chemical industry, smelting and coal, the production environment generally has the characteristics of high temperature, high pressure, much dust, volatile flammable and explosive medium, etc. Once the safety hidden danger of the cable product occurs, it is easy to cause fire, explosion and other serious safety accidents, which not only causes huge economic loss, but also threatens the life safety of the on-site operators. Therefore, the safety protection performance of the cable products in such special industries has a high rigid demand.

[0003] The intrinsically safe cable is a special cable product developed to adapt to the safety needs of the above-mentioned flammable and explosive harsh industrial environment. Its core application scenarios focus on environments with explosive hazards and industrial process control fields with extremely high reliability requirements. Compared with ordinary industrial automation cables, in addition to meeting the basic characteristics such as signal transmission stability and mechanical strength, intrinsically safe cables must also pass multiple harsh environmental level tests such as explosion-proof, anti-static and anti-electromagnetic interference. From the technical core requirements, intrinsically safe cables must have low capacitance and low inductance electrical characteristics. Low capacitance can avoid the accumulation of high voltage during signal transmission, and low inductance can reduce the induced electromotive force generated when the current changes. Both of them together ensure that the cable will not cause ignition source in flammable and explosive environment due to its own electrical characteristics; at the same time, the extremely high operation reliability is the key prerequisite for realizing the precise control of industrial process and ensuring the continuous stability of production.

[0004] At present, with the rapid development of industrial process automation products towards integration, networking and intelligence, the reliability and integration of automation systems in harsh environment industries such as petroleum and chemical industry are continuously improved, which in turn promotes the continuous growth of demand for high-performance intrinsically safe cables. Intrinsically safe cables, with their unique safety characteristics and adaptation ability, have become an important development direction of the cable industry in special industrial fields, and have broad market application prospects.

[0005] Although the research and application of intrinsically safe cables have made certain progress, the existing cable products still have many deficiencies to be solved in terms of safety performance in adapting to the extremely harsh production environment of petroleum, chemical industry, metallurgy and coal, which are specifically reflected in the following multiple key safety dimensions: Firstly, in terms of explosion-proof and anti-static performance, the protection level of existing intrinsic safety cables is difficult to fully match the use requirements in extremely flammable and explosive environments. Although some products can pass the basic explosion-proof test, they still have problems such as static discharge exceeding the standard, deterioration of explosion-proof sealing performance, and easy ignition risk in high-concentration flammable and explosive media, frequent mechanical friction, or severe static accumulation, which cannot fully guarantee production safety.

[0006] Secondly, in terms of environmental adaptability, the existing products lack sufficient resistance to extreme temperatures, oil pollution, and other harsh conditions. In high-temperature environments, the cable insulation layer is prone to aging and cracking, leading to a decline in insulation performance. In low-temperature environments, the cable material becomes brittle and the mechanical strength decreases, making it prone to damage due to laying or vibration. Moreover, most products have poor oil resistance and chemical corrosion resistance, and after long-term contact with industrial oil and chemical media, the sheath may swell and crack, affecting the safety protection effect and service life of the cable.

[0007] Thirdly, in terms of anti-interference performance, the existing intrinsic safety cables have limited shielding effect against electromagnetic interference. As the density of electrical equipment in industrial production areas increases, the electromagnetic environment becomes more complex. The shielding structure design of existing cables has defects, which cannot effectively block external electromagnetic signals from interfering with the transmission signals, leading to distortion of control signals and affecting the accuracy of industrial process control. At the same time, the electromagnetic radiation of some cables may also interfere with surrounding sensitive equipment, disrupting the stability of the entire automation system.

[0008] The above-mentioned safety performance deficiencies make it difficult for existing intrinsic safety cables to fully meet the high requirements for production safety, control accuracy, and system stability in extremely harsh industrial environments, restricting their application expansion in high-end industrial automation fields and failing to meet the core needs of the development of industrial automation towards comprehensiveness and intelligence. Therefore, developing an intrinsic safety cable with higher reliability and meeting the standards in all dimensions of explosion-proof, anti-static, anti-interference, extreme temperature resistance, and oil resistance, and its manufacturing method, has become a technical problem to be solved in the current field SUMMARY The purpose of the present application is to solve the problems of high cost caused by the large weight per unit size of the STP cable, large volume caused by the large outer diameter, flat twisted wire core caused by the increase of the metal shielding layer, unstable twisting pitch, and influence on signal transmission in the related art.

[0009] To achieve the above-mentioned purpose, the technical solution adopted by the present application is: In a first aspect, an intrinsic safety cable is provided, comprising: a filled core structure; A plurality of insulation core structures, the plurality of insulation core structures being arranged around the filling core structure with the filling core structure as the center; A protection structure, the protection structure being arranged around the plurality of insulation core structures; A shielding structure, the shielding structure being arranged around the protection structure; An interference structure, the interference structure being arranged around the shielding structure, for interfering with electromagnetic; A sheath structure, the sheath structure being arranged around the interference structure.

[0010] In some embodiments, the insulation core structure comprises: A plurality of insulation cores, the plurality of insulation cores being arranged in a twisted pair, the insulation core comprising a conductor, an inner protection layer and an inner insulation layer, the inner protection layer being arranged around the conductor, and the inner surface of the inner insulation layer being arranged close to the outer surface of the inner protection layer; An inner sheath layer, the inner sheath layer being arranged inside the insulation core; An inner shielding layer, the inner shielding layer being arranged inside the inner sheath layer; A flow guide wire, the flow guide wire being arranged on the inner shielding layer, and the extension direction of the flow guide wire being the same as the extension direction of the inner shielding layer.

[0011] In some embodiments, the conductor is 16 / 0.2 mm tinned copper.

[0012] In some embodiments, the twist pitch of the conductor is 16.6-18.5 mm.

[0013] In some embodiments, the twist pitch of the conductor is 18-20 times the outer diameter of the twist.

[0014] In some embodiments, the twist direction of the conductor is S direction.

[0015] In some embodiments, the inner protection layer is made of mica tape, the overlap rate of the mica tape is ≥50%, and the width of the mica tape is 5 mm.

[0016] In some embodiments, the inner insulation layer is made of XLPE, the thickness of the inner insulation layer is 0.6-0.7 mm, and the outer diameter of the inner insulation layer is 2.4 mm.

[0017] In some embodiments, the thickness of the inner sheath layer is ≥0.4 mm, and the outer diameter of the inner sheath layer is 5.7 mm.

[0018] In some embodiments, the flow guide wire is 16 / 0.2 mm tinned copper.

[0019] In some embodiments, the inner shielding layer is made of double-sided aluminum foil, and the width of the double-sided aluminum foil is 30 mm In some embodiments, the pitch of the insulation core structures is different, and the twist directions of the insulation core structures are different.

[0020] In some embodiments, the pitch of the insulation core structures is 45-60 mm.

[0021] In some embodiments, the number of insulation core structures is even, and the twist directions of adjacent insulation core structures are S and Z, respectively.

[0022] In some embodiments, the filling core structure is made of glass fiber, and the diameter of the filling core structure is 2.5 mm.

[0023] In some embodiments, the thickness of the protective structure is greater than or equal to 1.2 mm, and the outer diameter of the protective structure is 17 mm.

[0024] In some embodiments, the shielding structure is obtained by braiding tin-plated copper, and the braiding density is greater than or equal to 85%.

[0025] In some embodiments, the interference structure is made of aluminum foil Mylar, and the overlap rate is greater than or equal to 25%.

[0026] In some embodiments, the sheath structure is obtained by braiding glass fiber, and the braiding density is greater than or equal to 95%, and the outer diameter of the sheath structure is 19.7 mm.

[0027] In some embodiments, the twist pitch of the intrinsically safe cable is 16-18 times the outer diameter of the intrinsically safe cable.

[0028] In some embodiments, the twist pitch of the intrinsically safe cable is 16-18 times the outer diameter of the intrinsically safe cable. A method for preparing an intrinsically safe cable is provided in the second aspect, which is used to prepare the intrinsically safe cable of the first aspect, and includes: Cabling process is performed on the insulation core structures and the filling core structure; After the cabling process is completed, an extrusion process is performed on the outer side of the insulation core structures to form a protective structure; A first braiding process is performed on the outer side of the protective structure to form a shielding structure; A wrapping process is performed on the outer side of the shielding structure to form an interference structure;

[0029] In some embodiments, the method for preparing the insulation core structure includes: A winding process is performed on the outside of the conductor to form an inner protective layer, wherein the inner protective layer is made of mica tape with an overlap rate of ≥50%; An irradiation crosslinking process is performed on the outside of the inner protective layer to form an inner insulating layer, ultimately forming an insulating core, wherein the inner insulating layer is made of XLPE; The insulating cores are twisted together according to a preset pitch and a preset twisting direction. After the twisting process is completed, an extrusion process is performed on the outside of several of the insulating cores to form an inner sheath layer, wherein the inner sheath layer is made of PVC. A flow guide is provided on the outside of the inner sheath layer, and a wrapping process is performed to form an inner shielding layer, ultimately forming an insulating core structure. The inner shielding layer is made of double-sided aluminum foil.

[0030] In some of these embodiments, the conductor is 16 / 0.2 mm tin-plated copper.

[0031] In some of these embodiments, the conductor pitch is 16.6 to 18.5 mm.

[0032] In some of these embodiments, the conductor pitch is 18 to 20 times the stranded outer diameter.

[0033] In some of these embodiments, the conductor is stranded in the S-direction.

[0034] In some of these embodiments, the width of the mica strip is 5 mm.

[0035] In some embodiments, the thickness of the inner insulating layer is 0.6 to 0.7 mm, and the outer diameter of the inner insulating layer is 2.4 mm.

[0036] In some of these embodiments, the preset pitch is 45-60 mm, and the preset twist direction is S-direction or Z-direction.

[0037] In some embodiments, the thickness of the inner sheath layer is ≥0.4 mm, and the outer diameter of the inner sheath layer is 5.7 mm.

[0038] In some of these embodiments, the guide wire is 16 / 0.2 mm tin-plated copper.

[0039] In some of these embodiments, the width of the double-sided aluminum foil is 30 mm.

[0040] In some of the embodiments, the pitch and stranding direction of some of the insulating core structures are different.

[0041] In some embodiments, there are an even number of insulating core structures, and for two adjacent insulating core structures, the stranding direction of one insulating core structure is S and the stranding direction of the other insulating core structure is Z.

[0042] In some embodiments, the filling core structure is made of glass fiber with a specification of 2.5 mm.

[0043] In some embodiments, the thickness of the protective structure is ≥1.2 mm, and the outer diameter of the protective structure is 17 mm.

[0044] In some of the embodiments, the shielding structure is made of tin-plated copper braid with a braiding density of ≥85%.

[0045] In some of the embodiments, the interference structure is made of aluminum foil Mylar with an overlap rate of ≥25%.

[0046] In some embodiments, the sheath structure is made of fiberglass braid with a braiding density of ≥95% and an outer diameter of 19.7 mm.

[0047] The present invention adopts the above technical solution and has the following technical effects compared with the prior art: Compared with intrinsically safe cables in the prior art, the intrinsically safe cable of the present invention has safety performance such as cold resistance, high temperature resistance, oil resistance, antistatic properties, non-flammability, non-explosiveness, antistatic properties, and anti-interference properties. It also has low capacitance and low inductance, achieving high reliability, thereby meeting the comprehensive needs of industrial process automation. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of an intrinsically safe cable according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the insulating core structure according to an embodiment of the present invention.

[0049] The reference numerals in the attached figures are as follows: 10, filled core structure; 20, insulating core structure; 21, conductor; 22, inner insulating layer; 23, inner sheath layer; 24, inner shielding layer; 25, guide wire; 30, protective structure; 40, shielding structure; 50, interference structure; 60, sheath structure. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0052] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0053] Example 1 This embodiment relates to the intrinsically safe cable and its preparation method of the present invention.

[0054] An illustrative embodiment of the present invention, such as Figure 1 As shown, an intrinsically safe cable includes a filler core structure 10, a plurality of insulated core structures 20, a protective structure 30, a shielding structure 40, an interference structure 50, and a sheath structure 60. The plurality of insulated core structures 20 are arranged around the filler core structure 10 with the filler core structure 10 as the center; the protective structure 30 is arranged around the plurality of insulated core structures 20; the shielding structure 40 is arranged around the protective structure 30; the interference structure 50 is arranged around the shielding structure 40 and is used to interfere with electromagnetic interference; and the sheath structure 60 is arranged around the interference structure 50.

[0055] It should be noted that, in this invention, the twist pitch of the intrinsically safe cable is 16 to 18 times the outer diameter of the intrinsically safe cable.

[0056] It should be noted that, in this invention, the strand pitch of the intrinsically safe cable is 225~250 mm.

[0057] It should be noted that in this invention, the filler core structure 10 is located at the center of the intrinsically safe cable, and a plurality of insulating core structures 20 are distributed around the outside of the filler core structure 10.

[0058] It should be noted that in this invention, the filling core structure 10 is made of glass fiber.

[0059] In some of the embodiments described, the diameter of the core structure 10 is 2.5 mm.

[0060] It should be noted that, in this invention, the purpose of using the filler core structure 10 is to keep the intrinsically safe cable round.

[0061] Generally, a portion of the insulating core structure 20 is in contact with a portion of the filler core structure 10. That is, the insulating core structure 20 and the filler core structure 10 are approximately tangent to each other.

[0062] Whether two adjacent insulating core structures 20 are in contact depends on the number of insulating core structures 20, the size of the filler core structure 10, and the size of the insulating core structure 20.

[0063] It should be noted that in this invention, the number of insulating core structures 20 is generally an even number. The number is generally between 2 and 10. Preferably, the number is between 2 and 8, and more preferably between 2 and 6. In this invention, an example of 4 insulating core structures 20 will be used for illustration.

[0064] It should be noted that in this invention, the specifications of different insulating core structures 20 can be the same or different. Generally, in order to ensure signal transmission performance (i.e., to avoid mutual interference between several insulating core structures 20), insulating core structures 20 of different specifications are used.

[0065] It should be noted that, in this invention, the specifications of the insulating core structure 20 refer to the stranding pitch and stranding direction.

[0066] It should be noted that, in this invention, using different specifications of insulating core structures 20 means that the stranding pitch of all insulating core structures 20 is different, and the stranding direction of some insulating core structures 20 is different from that of other insulating core structures 20.

[0067] It should be noted that for two adjacent insulating core structures 20, the twisting directions of the two insulating core structures 20 are different. That is, several insulating core structures 20 with a first twisting direction are arranged at intervals, several insulating core structures 20 with a second twisting direction are arranged at intervals, an insulating core structure 20 with a second twisting direction is arranged between two adjacent insulating core structures 20 with a first twisting direction, and an insulating core structure 20 with a first twisting direction is arranged between two adjacent insulating core structures 20 with a second twisting direction.

[0068] It should be noted that one of the first twisting direction and the second twisting direction is S-direction and the other is Z-direction.

[0069] It should be noted that, in this invention, the stranding pitch of the insulating core structure 20 is 45~60 mm.

[0070] like Figure 2 As shown, the insulating core structure 20 includes several insulating cores, an inner sheath layer 23, an inner shielding layer 24, and a conductor 25. The insulating cores are twisted together, and each insulating core includes a conductor 21, an inner protective layer, and an inner insulating layer 22. The inner protective layer is wound around the conductor 21, and the inner surface of the inner insulating layer 22 is in close contact with the outer surface of the inner protective layer. The insulating cores are disposed inside the inner sheath layer 23. The inner sheath layer 23 is disposed inside the inner shielding layer 24. The conductor 25 is disposed within the inner shielding layer 24, and the extension direction of the conductor 25 is the same as the extension direction of the inner shielding layer 24.

[0071] In some embodiments, conductor 21 may be made of a single strand of wire or of multiple strands of wire twisted together.

[0072] In some embodiments, conductor 21 is 16 / 0.2 mm tin-plated copper. That is, conductor 21 is made of 16 strands of tin-plated copper wire with a diameter of 0.2 mm twisted together.

[0073] In some of these embodiments, the pitch of conductor 21 is 18 to 20 times the outer diameter of the strand.

[0074] In some of these embodiments, the strand pitch of conductor 21 is 16.6 to 18.5 mm.

[0075] In some of these embodiments, the conductor 21 is stranded in the S-direction.

[0076] In some of these embodiments, the inner protective layer is made of mica tape with a width of 5 mm and an overlap rate of ≥50%.

[0077] In some embodiments, the inner insulation layer 22 is made of XLPE (cross-linked polyethylene) at 125 degrees Celsius. It should be noted that 125 degrees Celsius refers to the long-term operating temperature of XLPE. That is, in this invention, the intrinsically safe cable can withstand high temperatures.

[0078] It should be noted that in this invention, the dielectric constant of XLPE is 2.8~3.2. XLPE with the above-mentioned properties allows the inner insulation layer 22 to have low capacitance and low inductance, resulting in superior data transmission capabilities compared to PVC insulation layers.

[0079] In some embodiments, the thickness of the inner insulating layer 22 is 0.6 to 0.7 mm, and the outer diameter of the inner insulating layer 22 is 2.4 mm.

[0080] It should be noted that the thickness of the inner insulation layer 22 is related to the cross-sectional area of ​​the conductor 21. For example, if the cross-sectional area of ​​the conductor 21 is 0.5~1.0 mm... 2 If the thickness of the inner insulation layer 22 is 0.6 mm, then the cross-sectional area of ​​the conductor 21 is 1.5 mm. 2 Therefore, the thickness of the inner insulation layer 22 is 0.7 mm.

[0081] In some of these embodiments, the inner sheath layer 23 is made of PVC material and has semi-conductive, cold-resistant, and explosion-proof properties.

[0082] In some of these embodiments, the thickness of the inner sheath layer 23 is ≥0.4 mm, and the outer diameter of the inner sheath layer 23 is 5.7 mm.

[0083] Preferably, the thickness of the inner sheath layer 23 is 0.4 mm to 0.5 mm.

[0084] In some embodiments, the inner shielding layer 24 is made of double-sided aluminum foil with a width of 30 mm and an overlap rate of ≥50%. It should be noted that using double-sided aluminum foil enhances the absorption of internal and external electromagnetic interference, ensuring the cable's electromagnetic compatibility meets relevant standards (such as the EU EMC directive). Furthermore, it enables intrinsically safe cables to meet low capacitance and low inductance requirements, while also providing good shielding performance, antistatic properties, and interference immunity.

[0085] In some embodiments, the guide wire 25 is 16 / 0.2 mm tin-plated copper. That is, the guide wire 25 is made of 16 strands of tin-plated copper wire with a diameter of 0.2 mm twisted together.

[0086] In some of these embodiments, the protective structure 30 is made of PVC material and has cold resistance, oil resistance and explosion-proof properties.

[0087] In some embodiments, the thickness of the protective structure 30 is ≥1.2 mm, and the outer diameter of the protective structure 30 is 17 mm.

[0088] In some of the embodiments, the shielding structure 40 is made of tin-plated copper braid with a braiding density of ≥85%.

[0089] In some of these embodiments, the shielding structure 40 is woven from 24 spindles of 12 strands of 0.15mm diameter tin-plated copper wire.

[0090] In some of the embodiments, the interference structure 50 is made of aluminum foil Mylar with an overlap rate of ≥25%.

[0091] In some of these embodiments, the sheath structure 60 is made of fiberglass braid with a braiding density of ≥95%.

[0092] In some of these embodiments, the sheath structure 60 is woven from 16 spindles of 8 strands of 0.5mm diameter glass fiber.

[0093] In some of these embodiments, the outer diameter of the sheath structure 60 is 19.7 mm.

[0094] The intrinsically safe cable described above is manufactured as follows: Step S1: A cable-making process is carried out on several insulating core structures 20 and filling core structures 10; Step S2: After completing the cabling process, an extrusion process is performed on the outside of several insulating core structures 20 to form a protective structure 30. Step S3: Perform the first weaving process on the outside of the protective structure 30 to form the shielding structure 40; Step S4: A wrapping process is formed on the outside of the shielding structure 40 to interfere with the structure 50; Step S5: Perform a second weaving process on the outside of the interference structure 50 to form the sheath structure 60.

[0095] The preparation method for the insulating core structure 20 in step S1 includes: Step S11: A winding process is performed on the outside of the conductor 21 to form an inner protective layer, wherein the inner protective layer is made of mica tape, and the overlap rate of the mica tape is ≥50%; Step S12: Perform an irradiation crosslinking process on the outside of the inner protective layer to form an inner insulating layer 22, ultimately forming an insulating core. The inner insulating layer 22 is made of XLPE. Step S13: Twist several insulating cores according to a preset pitch and preset twisting direction; Step S14: After completing the twisting process, an extrusion process is performed on the outside of several insulating cores to form an inner sheath layer 23, wherein the inner sheath layer 23 is made of PVC. Step S15: A guide line 25 is set on the outside of the inner sheath layer 23 and a wrapping process is performed to form an inner shielding layer 24, and finally an insulating core structure 20 is formed. The inner shielding layer 24 is made of double-sided aluminum foil.

[0096] For step S5, after the second weaving process, a coating process is also required.

[0097] The coating process includes applying two coats of clear varnish and then curing at high temperature.

[0098] The technical advantages of the intrinsically safe cable of the present invention are as follows: Compared with intrinsically safe cables in the prior art, the intrinsically safe cable of the present invention has safety performance such as cold resistance, high temperature resistance, oil resistance, antistatic properties, non-flammability, non-explosiveness, antistatic properties, and anti-interference properties. It also has low capacitance and low inductance, achieving high reliability, thereby meeting the comprehensive needs of industrial process automation.

[0099] Example 2 This embodiment relates to a specific implementation of the present invention.

[0100] In this embodiment, there are four insulating core structures 20, and the insulating core of each insulating core structure 20 is obtained by twisting two conductors 21 together. Specifically, the method for manufacturing intrinsically safe cables is as follows: Step 1: Conductor 21 is made of 16 / 0.20 mm tin-plated copper. The strand pitch of conductor 21 is 16.6~18.5 mm and the stranding direction is S. Wrap a 5 mm wide mica tape around conductor 21 to form an inner protective layer. The overlap rate of the mica tape is ≥50%, and the wound mica tape needs to be kept smooth to facilitate the extrusion of the inner insulation layer 22 in the subsequent process. Step 2: Using XLPE at 125 degrees Celsius, an insulation layer (i.e., inner insulation layer 22) with a thickness of 0.6 mm and an outer diameter of 2.4 mm is formed based on Step 1, and then irradiated crosslinking is performed; Step 3: Twist the two conductors 21 together. The first insulating core structure 20 has a twist pitch of 60 mm and a twist direction of S. The second insulating core structure 20 has a twist pitch of 55 mm and a twist direction of Z. The third insulating core structure 20 has a twist pitch of 50 mm and a twist direction of S. The fourth insulating core structure 20 has a twist pitch of 45 mm and a twist direction of Z. Step 4: Using semi-conductive cold-resistant PVC material, form a semi-conductive cold-resistant PVC inner sheath (i.e., inner sheath layer 23) with a thickness ≥ 0.4 mm and an outer diameter of 5.7 mm based on step 3. Step 5: Place the conductive wire 25 (16 / 0.2 mm tin-plated copper) on the semi-conductive cold-resistant PVC inner sheath, and tightly wrap it with double-sided aluminum foil with a width of 30 mm to form an inner shielding layer 24, with an overlap rate of ≥50% for the double-sided aluminum foil; Step 6: Fill the center of the cable with 2.5 mm glass fiber to form a filler core structure 10, so that the cable remains round and the cable strand pitch is 225~250 mm. Step 7: Using cold-resistant, explosion-proof, and oil-resistant PVC, form a protective structure 30 with a thickness ≥ 1.2 mm and an outer diameter of 17 mm based on Step 6; Step 8: Using 24 spindles of 12 tin-plated copper wires with a diameter of 0.15mm, braid them based on the work done in Step 7 to form a shielding structure 40, with a braiding density ≥85%; Step 9: Wrap a 60 mm wide aluminum foil Mylar around the structure from step 8 to form an interference structure 50, with an overlap rate of ≥25%. Step 10: Using 16 spindles of 8 glass fibers with a diameter of 0.5 mm, based on step 9, the fibers are first woven, then coated with a second varnish, and finally cured at high temperature in a hot runner to form a sheath structure 60 with an outer diameter of 19.7 mm.

[0101] The above description is merely a preferred embodiment of the present invention and does not limit the implementation and protection scope of the present invention. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. An intrinsically safe cable, characterized in that, include: Filled core structure; A plurality of insulating core structures, wherein the plurality of insulating core structures are arranged around the filling core structure as the center; A protective structure, wherein the protective structure is arranged to surround a plurality of the insulating core structures; A shielding structure, wherein the shielding structure is arranged to surround the protective structure; An interference structure, which surrounds the shielding structure, is used to interfere with electromagnetic interference. A sheath structure is provided to surround the interference structure.

2. The intrinsically safe cable according to claim 1, characterized in that, The insulating core structure includes: A plurality of insulating cores are twisted together. Each insulating core includes a conductor, an inner protective layer, and an inner insulating layer. The inner protective layer is wound around the conductor, and the inner surface of the inner insulating layer is in close contact with the outer surface of the inner protective layer. Inner sheath layer, wherein the insulating core is disposed inside the inner sheath layer; An inner shielding layer, wherein the inner shielding layer is provided with an inner sheath layer inside the inner shielding layer; A flow guide line is disposed in the inner shielding layer, and the extension direction of the flow guide line is the same as the extension direction of the inner shielding layer.

3. The intrinsically safe cable according to claim 2, characterized in that, The conductor is 16 / 0.2 mm tin-plated copper; and / or The conductor's strand pitch is 16.6~18.5 mm; and / or The conductor's lay length is 18 to 20 times the outer diameter of the strand; and / or The conductor is stranded in the S direction; and / or The inner protective layer is made of mica tape, with an overlap rate of ≥50% and a width of 5 mm; and / or The inner insulation layer is made of XLPE, the thickness of the inner insulation layer is 0.6~0.7 mm, and the outer diameter of the inner insulation layer is 2.4 mm; and / or The thickness of the inner sheath layer is ≥0.4 mm, and the outer diameter of the inner sheath layer is 5.7 mm; and / or The guide wire is 16 / 0.2 mm tin-plated copper; and / or The inner shielding layer is made of double-sided aluminum foil with a width of 30 mm.

4. The intrinsically safe cable according to claim 1, characterized in that, The pitch and stranding direction of some of the aforementioned insulating core structures are different; and / or The pitch of the insulating core structure is 45~60 mm; and / or The number of insulating core structures is even. For two adjacent insulating core structures, the stranding direction of one insulating core structure is S and the stranding direction of the other insulating core structure is Z.

5. The intrinsically safe cable according to any one of claims 1 to 4, characterized in that, The filling core structure is made of glass fiber and has a diameter of 2.5 mm; and / or The thickness of the protective structure is ≥1.2 mm, and the outer diameter of the protective structure is 17 mm; and / or The shielding structure is made of tin-plated copper braid with a braiding density of ≥85%; and / or The interference structure is made of aluminum foil Mylar with an overlap rate ≥25%; and / or The sheath structure is made of fiberglass braid with a braiding density of ≥95%, and the outer diameter of the sheath structure is 19.7 mm; and / or The twist pitch of the intrinsically safe cable is 16 to 18 times the outer diameter of the intrinsically safe cable.

6. A method for preparing an intrinsically safe cable, used to prepare the intrinsically safe cable as described in any one of claims 1 to 5, characterized in that, include: The cable-making process involves combining several insulating core structures with filler core structures. After the cabling process is completed, an extrusion process is performed on the outside of several of the aforementioned insulating core structures to form a protective structure; A first weaving process is performed on the outside of the protective structure to form a shielding structure; A wrapping process is formed on the outside of the shielding structure to interfere with the structure; A second weaving process is performed on the outside of the interference structure to form a sheath structure.

7. The preparation method according to claim 6, characterized in that, Methods for preparing insulating core structures include: A winding process is performed on the outside of the conductor to form an inner protective layer, wherein the inner protective layer is made of mica tape with an overlap rate of ≥50%; An irradiation crosslinking process is performed on the outside of the inner protective layer to form an inner insulating layer, ultimately forming an insulating core, wherein the inner insulating layer is made of XLPE; The insulating cores are twisted together according to a preset pitch and a preset twisting direction. After the twisting process is completed, an extrusion process is performed on the outside of several of the insulating cores to form an inner sheath layer, wherein the inner sheath layer is made of PVC. A flow guide is provided on the outside of the inner sheath layer, and a wrapping process is performed to form an inner shielding layer, ultimately forming an insulating core structure. The inner shielding layer is made of double-sided aluminum foil.

8. The preparation method according to claim 7, characterized in that, The conductor is 16 / 0.2 mm tin-plated copper; and / or The conductor's strand pitch is 16.6~18.5 mm; and / or The conductor's lay length is 18 to 20 times the outer diameter of the strand; and / or The conductor is stranded in the S direction; and / or The width of the mica strip is 5 mm; and / or The thickness of the inner insulation layer is 0.6~0.7 mm, and the outer diameter of the inner insulation layer is 2.4 mm; and / or The preset pitch is 45~60 mm, and the preset twist direction is S-axis or Z-axis; and / or The thickness of the inner sheath layer is ≥0.4 mm, and the outer diameter of the inner sheath layer is 5.7 mm; and / or The guide wire is 16 / 0.2 mm tin-plated copper; and / or The width of the double-sided aluminum foil is 30 mm.

9. The preparation method according to claim 6, characterized in that, The pitch and stranding direction of some of the aforementioned insulating core structures are different; and / or The number of insulating core structures is even. For two adjacent insulating core structures, the stranding direction of one insulating core structure is S and the stranding direction of the other insulating core structure is Z.

10. The preparation method according to any one of claims 6 to 9, characterized in that, The filling core structure is made of glass fiber with a specification of 2.5 mm; and / or The thickness of the protective structure is ≥1.2 mm, and the outer diameter of the protective structure is 17 mm; and / or The shielding structure is made of tin-plated copper braid with a braiding density of ≥85%; and / or The interference structure is made of aluminum foil Mylar with an overlap rate ≥25%; and / or The sheath structure is made of fiberglass braid with a braiding density of ≥95% and an outer diameter of 19.7mm.

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