Optical cable and preparation method thereof

Abstract

The invention belongs to the field of optical fiber cables, and particularly discloses an optical cable and a preparation method thereof, and the optical cable comprises an optical fiber and a composite layer which are sequentially arranged from inside to outside in the radial direction of the optical cable; the composite layer comprises a matrix and a hydrogen absorption material; the base body is obtained by curing a base material capable of being subjected to process curing, and the hydrogen absorption material can react with hydrogen-rich gas to absorb hydrogen in the hydrogen-rich gas; the hydrogen absorption material is distributed in the base body in a dispersed mode or distributed in the base body at intervals in a layered mode, the weight ratio of the hydrogen absorption material in the base body ranges from 0.2% to 25%, and when the hydrogen absorption material is distributed in the base body at intervals in a layered mode, the composite layer comprises at least one of a pure base body layer, a pure hydrogen absorption material layer and a base body and hydrogen absorption material mixed layer. According to the application, the lightweight optical cable which is good in short-term use airtightness and stable in optical transmission performance is provided, the optical cable is suitable for short-term oil and gas exploitation, and optical cable recovery does not need to be considered after use or is very convenient to recover.

Description

Technical Field

[0001] The present invention relates to the field of optical fiber cables, and more specifically, to an optical cable and a method for preparing the same. Background Art

[0002] The optical cables used in oil and gas extraction generally need to withstand harsh environments such as high temperature, high pressure, and hydrogen-rich gas. Therefore, the industry currently generally uses metal armored structure optical cables, or non-metallic sealed armored optical cables. Typical optical cables in the industry include 6.35mm metal armored oil well optical cables, 5.6mm double-layer twisted armored optical cables, or oil well optical cables reinforced by multiple layers of metal or steel wire twisting; the aforementioned types of optical cables require metal armor and / or multiple layers of metal twisting, which are more expensive to use, and the optical cables are larger in diameter and heavier in weight. After use, the optical cables need to be recycled to avoid affecting the oil well extraction work or the ecological environment of the mined oil wells. Therefore, the existing optical cable downhole projects of the above types are relatively large.

[0003] The industry is currently developing optical cable products that can be used for short-term sensor communications. However, conventional optical fiber products are too strong and very easy to break, making them difficult to use. Currently commonly used tight-sleeved products have average temperature resistance or low tensile strength, and these tight-sleeved products all use non-metallic extruded structures with relatively poor airtightness. Under high temperature and high pressure conditions during the downhole process, hydrogen-rich gas will quickly diffuse into the fiber core, causing hydrogen loss and resulting in test errors. Summary of the invention

[0004] In view of the defects of the prior art, the purpose of this application is to provide an optical cable and a preparation method thereof, aiming to solve the problems that the existing short-term use optical cables have general temperature resistance, low tensile strength and poor air tightness, which affect the performance of the optical cables.

[0005] To achieve the above-mentioned object, in a first aspect, the present application provides an optical cable, comprising: optical fibers and composite layers arranged in sequence from inside to outside along the radial direction of the optical cable; The composite layer comprises: a matrix and a hydrogen absorbing material; the matrix is ​​obtained by curing a substrate capable of process curing, and the hydrogen absorbing material can react with the hydrogen-rich gas to absorb hydrogen in the hydrogen-rich gas; The hydrogen absorbing material is dispersed in the matrix or distributed in layers and intervals in the matrix, and the weight proportion of the hydrogen absorbing material in the matrix ranges from 0.2% to 25%; when the hydrogen absorbing material is distributed in layers and intervals in the matrix, the composite layer includes at least one of a pure matrix layer, a pure hydrogen absorbing material layer and a mixed layer of a matrix and a hydrogen absorbing material.

[0006] It should be noted that the matrix of the composite layer of the present application is doped with hydrogen absorbing materials, and the above hydrogen absorbing materials have better hydrogen adsorption capacity. By controlling the weight ratio of the hydrogen absorbing materials in the matrix, the optical cable can be adapted to work scenarios with different hydrogen absorption requirements. Furthermore, the matrix of the above composite layer is obtained by solidifying the base material; those skilled in the art will know that the materials that can usually be solidified are generally non-metallic materials, which have certain tensile and compressive resistance after solidification, and the weight of the above composite layer will be much lighter than the weight of the metal armor or metal twisted layer on the periphery of the existing optical cable. Therefore, the optical cable in the present application can be understood as a lightweight optical cable, the self-weight of the optical cable is greatly reduced, and the tensile requirements of the optical cable will be greatly reduced when the optical cable is used perpendicular to the direction of gravity; and when the weight of the optical cable is relatively light, the above optical cable has certain tensile and compressive resistance, which can meet the use requirements.

[0007] In a possible implementation, the composite layer further includes: a fiber layer located on the inner surface of the composite layer, at least one location inside the composite layer, or at least one location on the outer surface of the composite layer along the radial direction of the optical cable; the fiber layer is obtained by wrapping and winding a plurality of fibers along the length extension direction of the optical cable; preferably, the elastic modulus of the fiber layer is greater than a preset modulus; further preferably, the preset modulus is 90 GPa to 150 GPa; And / or the outer diameter range of the composite layer is: 0.45mm~1.80mm.

[0008] It should be noted that when the tensile strength requirement of the optical cable exceeds a certain requirement, at least one fiber layer can be added to the composite layer to increase the tensile strength of the optical cable and ensure the stable working performance of the optical cable; wherein the number and thickness of the fiber layer can be set according to actual needs, without any limitation. Furthermore, when it is necessary to enhance the tensile strength of the optical cable, the elastic modulus of the above-mentioned fiber layer needs to be large enough, wherein the larger the elastic modulus, the higher the tensile strength of the fiber layer.

[0009] Further optionally, the outer diameter of the composite layer refers to the diameter of the outermost layer of the composite layer, that is, the diameter of the optical cable. Since the present application simplifies the structure of the optical cable, the outer diameter of the optical cable can be thinner, which is more portable and more convenient to use, and has a broader application prospect.

[0010] In a possible implementation, the substrate is a high temperature resistant substrate; preferably, the maximum high temperature resistant temperature of the high temperature resistant substrate is determined by the working environment temperature of the optical cable.

[0011] In one example, if the optical cable is used in oil well exploitation, the maximum high temperature resistance temperature of the substrate needs to be greater than or equal to the maximum temperature during oil well exploitation.

[0012] In a possible implementation, the hydrogen absorbing material includes one of the following materials: graphite and metal hydride; the specific surface area of ​​the metal hydride is greater than a preset value; preferably, the preset value is 50 m 2 / g; It is understandable that graphite generally has good hydrogen absorption capacity, and the larger the specific surface area of ​​the metal hydride, the greater the hydrogen absorption capacity. Therefore, a metal hydride with a relatively large specific surface area can be selected as the hydrogen absorption material used in this application.

[0013] In a possible implementation, the fibers in the fiber layer include at least one of the following materials: aramid, PI fiber, PBO fiber, LCP fiber, quartz fiber and carbon fiber; And / or the substrate includes at least one of the following materials: polyimide, silicone rubber and epoxy resin.

[0014] Specifically, the materials of the fiber layer and the substrate can be selected according to actual economic conditions, working environment requirements of the optical cable, etc., and this application does not make any further limitations on this.

[0015] In a possible implementation, the particle size of the hydrogen absorbing material is less than 50 microns.

[0016] It can be understood that when the particle size of the hydrogen absorbing material is smaller than a certain size, the adsorption efficiency of hydrogen by the hydrogen absorbing material will be improved.

[0017] In a possible implementation, the optical fiber includes a coating layer; preferably, the coating layer is a high temperature resistant coating layer; further preferably, the coating layer includes at least one of an acrylic resin coating layer, a silicone rubber coating layer, a polyimide coating layer or a carbon coating layer.

[0018] It should be noted that the coating layer can protect the inside of the optical fiber, and the use of a high temperature resistant coating layer can further improve the high temperature resistance of the optical fiber to ensure the high temperature resistance of the optical cable as a whole. Accordingly, the material of the coating layer can be selected according to the actual economic situation, the working environment requirements of the optical cable, etc., and this application does not make further restrictions on this.

[0019] In a second aspect, the present application provides an optical cable, comprising: an optical fiber; the optical fiber is replaced by the optical cable described in the above-mentioned first aspect or any possible implementation manner of the first aspect.

[0020] It is understandable that the outer diameter of the optical cable in the present application can be thinner, so the optical fiber in the existing optical cable can be replaced by the optical cable provided by the present application, thereby improving the hydrogen absorption, tensile strength or high temperature resistance of the existing optical cable.

[0021] In a third aspect, the present application provides a method for preparing an optical cable described in the first aspect or any possible implementation of the first aspect, comprising the following steps: A substrate and a hydrogen absorbing material are mixed and then coated on an optical fiber to obtain a composite coating; or at least one layer of substrate and at least one layer of hydrogen absorbing material are alternately coated on an optical fiber, and a layer of substrate is coated on the outermost layer to obtain a composite coating; the pressure range during coating is 2 to 10 atmospheres, and the temperature range is 25° C. to 80° C.; the weight proportion of the hydrogen absorbing material in the composite coating ranges from 0.2% to 25%; The composite coating is cured to obtain an optical cable.

[0022] In a possible implementation, the method further includes: Before, during or after coating the substrate and the hydrogen absorbing material on the optical fiber, wrapping a plurality of fibers around at least one of the optical fiber, the optical fiber having at least one partial thickness composite coating or the optical fiber having a complete composite coating along the length extension direction of the optical fiber to obtain a fiber layer; The composite coating is solidified, specifically, after the fiber layer and the composite coating are prepared on the periphery of the optical fiber, the composite coating is solidified to obtain an optical cable.

[0023] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the prior art: The present application provides an optical cable and a preparation method thereof, wherein the optical cable includes an optical fiber and a composite layer, wherein a hydrogen absorbing material is doped in a matrix of the composite layer, wherein the hydrogen absorbing material has a good hydrogen adsorption capacity, and the weight ratio of the hydrogen absorbing material in the matrix can be controlled to make the optical cable adapt to the working scenario of short-term use in oil well exploitation. Since the optical cable in the present application does not need to adopt a metal protective layer or a metal armor layer, the optical cable can be made thinner, and the optical cable can be understood as a lightweight optical cable at this time, and the self-weight of the optical cable is greatly reduced; when the optical cable is used perpendicular to the direction of gravity, the tensile requirements for the optical cable will be greatly reduced; and when the weight of the optical cable is relatively light, the above optical cable has a certain tensile and compressive resistance, which can meet the short-term use requirements of oil well exploitation. Furthermore, in the present application, by selecting a substrate and a hydrogen absorbing material, and controlling the weight ratio of the hydrogen absorbing material in the optical cable composite layer to be in the range of 0.2% to 25%, and the outer diameter range of the composite layer to be: 0.45mm to 1.80mm, an optical cable suitable for short-term use in an oil well environment can be obtained, which has high tensile strength, high temperature resistance, good air tightness, and stable optical transmission performance, and meets the unique needs of this scenario. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1( a ) is a schematic diagram of a first structure of an optical cable provided in an embodiment of the present application; FIG1( b ) is a schematic diagram of a second structure of an optical cable provided in an embodiment of the present application; FIG1( c ) is a schematic diagram of a third structure of an optical cable provided in an embodiment of the present application; Figure 2 This is a fourth structural schematic diagram of the optical cable provided in the embodiment of the present application; Figure 3 This is a fifth structural schematic diagram of an optical cable provided in an embodiment of the present application; Figure 4 This is a sixth structural schematic diagram of an optical cable provided in an embodiment of the present application; Figure 5 is a flow chart of a method for preparing an optical cable provided in an embodiment of the present application; In all the drawings, the same reference numerals are used to represent the same elements or structures, wherein: 10 is an optical fiber, 101 is a coating layer; 20 is a composite layer, 201 is a hydrogen absorbing material, 202 is a fiber layer, and 203 is a substrate layer. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0026] First, the technical terms involved in the embodiments of the present application are introduced.

[0027] (1) Optical cable Optical cable refers to a communication cable assembly that uses one or more optical fibers placed in a sheath as a transmission medium and can be used individually or in groups.

[0028] (2) Hydrogen-rich gas Hydrogen-rich gas refers to gas with a high hydrogen content. The specific threshold of hydrogen content can be found in the relevant standards issued by the state, and will not be specifically explained in the embodiments of this application.

[0029] (3) Hydrogen-rich environment A hydrogen-rich environment refers to an environment with a high hydrogen content. The specific threshold of hydrogen content can be found in the relevant standards issued by the state, and will not be specifically explained in the embodiments of this application.

[0030] (4) High temperature resistance High temperature resistance generally refers to the ability of a material to maintain its performance without significant changes in high temperature environments. Specifically, high temperature resistance standards can be defined based on specific material types and application requirements.

[0031] For example, in the field of optical cables, the high temperature resistance standard of the optical cable is usually determined by the environment in which it is used. Taking the application in oil well exploitation as an example, during the oil well exploitation process, the wellhead temperature is generally not lower than 80°C, and the bottom hole temperature is usually over 150°C, and sometimes even over 200°C. Therefore, the maximum high temperature resistance of the optical cable needs to reach over 80°C. If it can reach over 150°C, or even over 200°C, it will be more suitable for deep oil well exploitation applications, and the application prospects of optical cables in oil well exploitation will also be better.

[0032] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0033] FIG. 1( a ) is a schematic diagram of the first structure of an optical cable provided in an embodiment of the present application. As shown in FIG. 1( a ), the optical cable includes: an optical fiber 10 and a composite layer 20 .

[0034] The composite layer 20 includes: a matrix and a hydrogen absorbing material 201. The composite layer 20 is coated on the outer periphery of the optical fiber 10 along the radial direction of the optical cable. The main material of the composite layer 20 is the matrix, and the hydrogen absorbing material 201 is dispersed in the matrix.

[0035] Specifically, the matrix in the composite layer 20 is obtained by curing a substrate capable of being cured by a process, and the hydrogen absorbing material 201 can react with the hydrogen-rich gas to absorb hydrogen in the hydrogen-rich gas.

[0036] It should be noted that, in general, when optical cables are used in some special environments, they need to have better performance; for example, in hydrogen-rich environments, optical cables need to have better hydrogen resistance, in high-temperature environments, optical cables need to have high-temperature resistance, and in high-pressure environments, optical cables need to have pressure resistance. Moreover, in the actual process of going down to the well, the above parameters may be superimposed. At present, the industry uses bare fiber tests for going down to the well, which is mainly reflected in the lack of tensile strength, which easily leads to fiber breakage problems.

[0037] Conventional means usually involve setting a metal protective layer (metal armor) on the outer periphery of the optical cable and setting a hydrogen absorbing fiber paste on the optical fiber. The metal protective layer is usually made of metal materials with high oxidation resistance to achieve sealing of the optical fiber. As the metal protective layer oxidizes, its airtightness deteriorates, and a small amount of hydrogen will pass through the metal protective layer to the optical fiber, at which point the small amount of hydrogen will be absorbed by the hydrogen absorbing fiber paste. However, the above solution has a complex structure, large volume, and heavy weight, and the optical cable needs to be recycled after use, and the recycling process is not easy to operate.

[0038] In the embodiment of the present application, hydrogen absorbing material 201 is doped in the composite layer 20. The hydrogen absorbing material is different from the hydrogen absorbing fiber paste used in conventional optical cables, and its hydrogen adsorption capacity is significantly better than that of hydrogen absorbing fiber paste; some hydrogen absorbing materials can have a unit adsorption capacity higher than that of hydrogen absorbing fiber paste by at least one order of magnitude. Furthermore, the material that can usually be solidified is a non-metallic material with a light weight. Therefore, the present application can ensure that the optical cable has the ability to absorb hydrogen by doping the composite layer 20 with hydrogen absorbing material 201, and the structure is simple, the cable volume is small, and the weight is light. After the use of this optical cable, due to the small volume of the optical cable, the optical cable provided by the embodiment of the present application is relatively more environmentally friendly and lighter than the optical cable with a metal protective layer, so it is easier to recycle the optical cable and in some scenarios it can be directly discarded without recycling.

[0039] Further optionally, the weight ratio of the hydrogen absorbing material 201 in the matrix is ​​in the range of 0.2% to 25%.

[0040] Further optionally, the hydrogen absorbing material 201 comprises at least one of the following materials: graphite and metal hydride. Generally, graphite has a good hydrogen absorbing ability, and the larger the specific surface area of ​​the metal hydride, the higher the hydrogen absorbing ability. Preferably, the specific surface area of ​​the metal hydride is greater than a preset value; for example, the preset value is 50 m 2 / g; It should be noted that graphite or metal hydrides with high specific surface area are selected as hydrogen absorbing materials in the embodiments of the present application. The reason is that these two hydrogen absorbing materials have a faster hydrogen absorption reaction and a stronger ability to adsorb hydrogen. In other words, based on the selection of the above hydrogen absorbing materials, the thin-diameter lightweight optical cable with better short-term hydrogen absorption performance mentioned in the embodiments of the present application can be prepared.

[0041] Furthermore, compared with conventional environments, high temperature and high pressure environments have higher hydrogen partial pressure and higher hydrogen permeation rate under high pressure and high temperature conditions, so higher requirements are placed on the hydrogen loss resistance of optical cables used under such environmental conditions. Generally speaking, the higher the proportion of hydrogen absorbing materials in the material, the better the hydrogen absorption effect, but there are many restrictions in the actual material design process.

[0042] On the one hand, when the hydrogen absorbing material is below a certain mass specific gravity, the distance between the hydrogen absorbing particles will increase. However, the hydrogen absorbing material's adsorption of hydrogen will be greatly weakened as the distance increases, which may reduce the hydrogen absorbing material's effective ability to capture hydrogen. On the other hand, when the weight proportion of the hydrogen absorbing material increases to a certain extent, the distance between the hydrogen absorbing particles will be greatly reduced, and even some of the hydrogen absorbing materials will be difficult to form matrix material infiltration, which will cause the mechanical properties of the composite layer to drop significantly. For the above reasons, the mass proportion of the hydrogen absorbing material should be controlled between 0.2% and 25%.

[0043] Further preferably, the weight proportion of the hydrogen absorbing material is determined by the working environment and working time of the optical cable.

[0044] It is understandable that by selecting appropriate hydrogen absorbing materials and controlling the weight ratio of the hydrogen absorbing materials in the matrix, the optical cable can be adapted to working scenarios with different hydrogen absorption requirements.

[0045] For example, the above-mentioned hydrogen absorption demand may refer to: for example, an optical cable used for a short period of time may be used for 3 days, 7 days, 10 days, 21 days or 1 month, etc. During the working time of the optical cable, the optical cable can absorb the hydrogen in the hydrogen-rich gas in the working environment, so that the hydrogen cannot reach the surface of the optical fiber and will not affect the performance of the optical fiber.

[0046] Specifically, the diffusion rate of hydrogen is related to the concentration of hydrogen-rich gas in the working environment (the concentration of hydrogen in the hydrogen-rich gas is determined) and the ambient temperature; for example, the higher the ambient temperature, the greater the ambient pressure, and the higher the concentration of hydrogen-rich gas (the higher the hydrogen concentration), the faster the hydrogen penetrates the above-mentioned composite layer and diffuses in the composite layer. In one embodiment, the total weight of hydrogen that needs to be adsorbed by the hydrogen absorbing material 201 can be determined based on the working time of the optical cable, combined with the temperature of its working environment and the concentration of hydrogen-rich gas, and then the weight ratio of the hydrogen absorbing material 201 in the composite layer 20 can be determined in combination with the outer diameter parameters of the optical cable composite layer and the material parameters of the matrix in the composite layer, so as to prepare the optical cable.

[0047] In other embodiments, as shown in FIG. 1(b) and FIG. 1(c), the hydrogen absorbing material 202 can also be distributed in layers and intervals in the matrix. When the hydrogen absorbing material is distributed in layers and intervals in the matrix, the composite layer includes at least one of a pure matrix layer, a pure hydrogen absorbing material layer, and a matrix and hydrogen absorbing material mixed layer. Then the above-mentioned composite layer 20 includes at least one layer of hydrogen absorbing material 202 and at least one layer of matrix layer 203, and can even include a matrix and hydrogen absorbing material mixed layer (not shown in the figure, see the composite layer shown in FIG. 1(a)), and the outermost layer of the composite layer 20 is a matrix layer 203, so as to be able to wrap and seal the optical cable. The innermost layer of the composite layer 20 can be a hydrogen absorbing material (as shown in FIG. 1(b)), or a matrix layer 203 (as shown in FIG. 1(c)).

[0048] It is understandable that the matrix of the above-mentioned composite layer is obtained by solidifying the base material; those skilled in the art will know that the materials that can be solidified are generally non-metallic materials, so the weight of the above-mentioned composite layer in this application will be much lighter than the weight of the metal armor or metal twisted layer on the periphery of the existing optical cable. Therefore, the optical cable in this application can be understood as a lightweight optical cable; for the optical cable, especially when the optical cable needs to be suspended in the direction of its gravity to work (such as oil well mining), the gravity it receives mostly comes from its own weight, so if the optical cable is heavier (such as an optical cable with a metal armor or metal twisted layer), it needs to have a higher tensile strength. However, since the lightweight optical cable is given in this application, the tensile strength requirements of the optical cable will be greatly reduced. When the weight of the optical cable is lighter, the optical cable usually has a certain pressure resistance and tensile strength, which can meet the use requirements.

[0049] When the high temperature resistance requirements for the optical cable are higher, the above-mentioned substrate can adopt a high temperature resistant substrate; preferably, the maximum high temperature resistant temperature of the above-mentioned high temperature resistant substrate is determined by the working environment temperature of the optical cable to ensure that the optical cable provided in the embodiment of the present application can work in a high temperature environment.

[0050] In one example, the substrate used in the substrate includes at least one of the following materials: polyimide, silicone rubber, epoxy resin, etc. After the substrate is cured, the obtained substrate should have high temperature resistance. Those skilled in the art can select other types of high temperature resistant substrates according to needs to meet specific work requirements.

[0051] In one embodiment, when the optical cable works in a high temperature environment, in addition to the composite layer 20 having high temperature resistance, the optical fiber inside it also needs to have high temperature resistance. Generally, a coating layer 101 can be provided on the periphery of the optical fiber 10 to improve its high temperature resistance and also to protect the inside of the optical fiber.

[0052] Preferably, the coating layer 101 is a high temperature resistant coating layer; further preferably, the coating layer 101 includes at least one of an acrylic resin coating layer, a silicone rubber coating layer, a polyimide coating layer or a carbon coating layer.

[0053] In some embodiments, the composite layer 20 further includes: a fiber layer located on the inner surface of the composite layer, at least one location inside the composite layer, or at least one location on the outer surface of the composite layer along the radial direction of the optical cable. It can be understood that if the hydrogen absorbing material is dispersed in the matrix, then the composite layer is an integral hydrogen absorbing material-matrix composite layer. If the hydrogen absorbing material is distributed in layers and intervals in the matrix, then the composite layer includes a pure matrix layer, a pure hydrogen absorbing material layer, and may even include a composite layer of the matrix and the hydrogen absorbing material, and the above multi-layer structure constitutes a hydrogen absorbing material-matrix composite layer. If the above composite layer also includes a fiber layer, the fiber layer can exist as a separate layer, or the fiber layer can be interspersed in each layer such as the pure matrix layer, the pure hydrogen absorbing material layer, and the hydrogen absorbing material-matrix composite layer.

[0054] Further preferably, the fiber layer 202 can be located on the inner surface of the composite layer 20 along the radial direction of the optical cable, such as Figure 2 shown.

[0055] Further optionally, the fiber layer 202 can be located inside the composite layer 20 along the radial direction of the optical cable; Figure 3 shown.

[0056] Further optionally, the fiber layer 202 can be located on the outer surface of the composite layer 20 along the radial direction of the optical cable, such as Figure 4 shown.

[0057] See also Figures 2 to 4 As shown, the fiber layer 202 can be obtained by wrapping and winding multiple fibers along the length extension direction of the optical cable. In addition, the fiber layer 202 can have multiple layers or a thicker layer to increase the tensile strength of the optical cable. It should be noted that the specific fiber winding method can refer to the method of setting the fiber layer in the existing optical fiber or optical cable, so as to improve the tensile strength or tensile performance of the optical cable, and no limitation or elaboration is made here.

[0058] Preferably, the elastic modulus of the fiber layer 202 is greater than a preset modulus; further preferably, the preset modulus is 90 GPa to 150 GPa.

[0059] The larger the elastic modulus threshold is, the better the tensile performance of the fiber layer will be. Correspondingly, the tensile performance of the optical cable will also be higher, and the application scenarios of the optical cable will be wider.

[0060] In one embodiment, the fibers in the fiber layer 202 include at least one of the following materials: aramid, PI fiber, PBO fiber, LCP fiber, quartz fiber, carbon fiber and the like.

[0061] It can be understood that the fiber layer 202 is used as a tensile element of the optical cable, and the specific usage amount can be designed according to the tensile requirements of the optical cable and the outer diameter of the optical cable.

[0062] Figure 5 is a flow chart of the method for preparing an optical cable provided in an embodiment of the present application; Figure 5 As shown, the following steps are included: Step S101, mixing a substrate with a hydrogen absorbing material to obtain a mixture; It is understandable that the above-mentioned mixing may specifically be: the above-mentioned base material is in a liquid state before solidification, and the above-mentioned hydrogen absorbing material is fully mixed with the base material in a liquid state, and the mixture is mixed as evenly as possible to obtain a corresponding mixture.

[0063] The weight proportion of the hydrogen absorbing material in the matrix can range from 0.2% to 25%. The above hydrogen absorbing materials can ensure that when the hydrogen-rich gas penetrates the high-temperature substrate, it reacts with the hydrogen absorbing material in time without reaching the surface of the optical fiber.

[0064] Further optionally, the hydrogen absorbing material is in a particle dispersed state in the matrix. To improve the hydrogen adsorption efficiency of the hydrogen absorbing material, the particle size of the hydrogen absorbing material can be controlled to be less than 50 microns.

[0065] Step S102, coating the mixture on the optical fiber to obtain a composite coating; Preferably, the pressure range during coating is 2-10 atmospheres, and the temperature range is 25°C-80°C, to ensure that the mixture has good fluidity during the coating process to improve the coating effect; the above coating effect includes: the thickness of the coating process is uniform and controllable.

[0066] Step S103, curing the composite coating to obtain an optical cable.

[0067] It is understood that the base material and the hydrogen absorbing material are fully mixed during the preparation of the optical cable, and then the mixture corresponding to the above mixed materials can be injected into a pressure vessel, the pressure in the pressure vessel can be controlled at 2 to 10 atmospheres according to the viscosity of the base material, and the temperature can be controlled at 25°C to 80°C according to the actual viscosity of the base material to ensure the fluidity of the material during coating. The optical fiber is coated by a coater, and an appropriate coating mold is selected according to the outer diameter of the designed optical cable.

[0068] Specifically, due to the certain shrinkage during the curing process of the material, the coating inlet mold is generally selected to increase the outer diameter of the optical fiber by 10 microns to 30 microns, and the outlet mold is selected to increase the outer diameter of the finished optical cable by 20 microns to 100 microns.

[0069] It can be understood that the above-mentioned curing methods may include: UV curing, thermal curing, LED curing and other curing methods, and the specific curing method can be selected according to the material properties of the substrate or the mixture.

[0070] The above preparation method can be used to prepare Figures 2 to 4When preparing the optical cable of the structure shown in FIG. 1( b ) and FIG. 1( c ), the above steps S101 and S102 are combined into the following steps: coating the optical fiber with at least one layer of substrate and at least one layer of hydrogen absorbing material at intervals, and coating the outermost layer with a layer of substrate to obtain a composite coating. The coating conditions remain unchanged.

[0071] In one embodiment, after curing, the outer diameter range of the above-mentioned composite layer is: 0.45mm~1.80mm. Since the structure of the optical cable in this application is simple and lightweight. Since the composite layer is doped with hydrogen-absorbing materials, the optical cable can work normally under a certain working time. For example, it is suitable for short-term use in a hydrogen-rich environment, such as oil well mining; therefore, the outer diameter of the composite layer of the optical cable in this application does not need to be too thick, the size of the optical cable is small, and it can be prepared into a thin-diameter optical cable, which will be more convenient to carry and use; and after the subsequent use of the optical cable, it is easier to recycle, or it can be directly discarded without recycling.

[0072] Further optionally, when it is necessary to prepare a fiber layer in an optical cable, before, during or after coating the substrate and the hydrogen absorbing material on the optical fiber, a plurality of fiber wraps are wound around the periphery of at least one of the optical fiber, the optical fiber having at least one partial thickness composite coating or the optical fiber having a complete composite coating along the length extension direction of the optical fiber to obtain the fiber layer; The composite coating is solidified, specifically, after the fiber layer and the composite coating are prepared on the periphery of the optical fiber, the composite coating is solidified to obtain an optical cable.

[0073] In order to better illustrate the performance characteristics of the optical cable provided in the embodiment of the present application, further comparative analysis is performed through the following specific embodiments, and the relevant parameters of each embodiment are shown in Table 1: Table 1

[0074] Combined with Table 1, it can be seen that the breaking force of the optical cable prepared in the embodiment of the present application can achieve a range of 100N-1000N, and the long-term use temperature of the optical cable covers 85℃-350℃. It can be seen that the optical cable provided in the embodiment of the present application has the characteristics of high tensile strength, high temperature resistance, good airtightness, stable optical transmission performance, etc., which is very suitable for short-term use in related environments. It can be seen that in this application, by selecting the substrate and hydrogen absorbing material, and controlling the weight proportion of the hydrogen absorbing material in the optical cable composite layer to be in the range of 0.2%~25%, and the outer diameter range of the composite layer is: 0.45mm~1.80mm, a kind of optical cable suitable for short-term use in the oil well environment, with high tensile strength, high temperature resistance, good airtightness, and stable optical transmission performance can be obtained to meet the unique needs of this scenario.

[0075] When the above optical cable is used in oil well mining, the product can be pumped down the well and can be used as a medium for monitoring temperature, vibration and other signals in a short period of time. At the same time, the product can also be used for optical communications in other special high temperature, high pressure and hydrogen loss environments.

[0076] It can be understood that in order to improve the hydrogen absorption, tensile strength or high temperature resistance of the existing optical cable, the optical fiber in the existing optical cable can be replaced by the optical cable provided by the embodiment of the present application; obviously, after the above-mentioned optical cable replaces the optical fiber in the existing optical cable, the hydrogen absorption capacity (the hydrogen absorption capacity of the hydrogen absorbing material is better than the hydrogen absorption capacity of the hydrogen absorbing fiber paste), high temperature resistance and tensile strength of the existing optical cable can be improved.

[0077] It should be understood that expressions such as "including" and "may include" that may be used in the present application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In the present application, terms such as "including" and / or "having" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components, or combinations thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0078] In addition, in the present application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" may include A, may include B, or may include both A and B.

[0079] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Among them, "fixed connection" means that the relative position relationship after connection remains unchanged. "Rotational connection" means that the two are connected to each other and can rotate relative to each other after connection. "Sliding connection" means that the two are connected to each other and can slide relative to each other after connection. The directional terms mentioned in the embodiments of the present application, such as "top", "bottom", "inside", "outside", "left", "right", etc., are only reference directions of the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of the present application, 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 on the embodiments of the present application.

[0080] In addition, in the embodiments of the present application, the mathematical concepts mentioned are symmetry, equality, parallelism, verticality, etc. These limitations are all for the current state of the art, rather than being absolutely strict definitions in a mathematical sense, and allow a small amount of deviation, approximation to symmetry, approximation to equality, approximation to parallelism, approximation to verticality, etc. are all possible. For example, A and B are parallel, which means that A and B are parallel or approximately parallel, and the angle between A and B can be between 0 and 10 degrees. A and B are perpendicular, which means that A and B are perpendicular or approximately perpendicular, and the angle between A and B can be between 80 and 100 degrees.

[0081] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. An optical cable, characterized in that: include: Optical fibers and composite layers are arranged in sequence from inside to outside along the radial direction of the optical cable; The composite layer comprises: a substrate and a hydrogen absorbing material; The matrix is ​​obtained by curing a substrate capable of process curing, and the hydrogen absorbing material can react with the hydrogen-rich gas to absorb hydrogen in the hydrogen-rich gas; The hydrogen absorbing material is dispersed in the matrix or distributed in layers and intervals in the matrix, and the weight proportion of the hydrogen absorbing material in the matrix ranges from 0.2% to 25%; when the hydrogen absorbing material is distributed in layers and intervals in the matrix, the composite layer includes at least one of a pure matrix layer, a pure hydrogen absorbing material layer and a mixed layer of a matrix and a hydrogen absorbing material.

2. The optical cable according to claim 1, characterized in that The composite layer further comprises: a fiber layer located on the inner surface of the composite layer, at least one location inside the composite layer, or at least one location on the outer surface of the composite layer along the radial direction of the optical cable; the fiber layer is obtained by wrapping and winding a plurality of fibers along the length extension direction of the optical cable; preferably, the elastic modulus of the fiber layer is greater than a preset modulus; further preferably, the preset modulus is 90 GPa to 150 GPa; And / or the outer diameter range of the composite layer is: 0.45mm~1.80mm.

3. The optical cable according to claim 1, characterized in that The substrate is a high temperature resistant substrate; preferably, the maximum high temperature resistant temperature of the high temperature resistant substrate is determined by the working environment temperature of the optical cable.

4. The optical cable according to any one of claims 1 to 3, characterized in that: The hydrogen absorbing material comprises one of the following materials: graphite and metal hydride; the specific surface area of ​​the metal hydride is greater than a preset value; preferably, the preset value is 50m 2 / g.

5. The optical cable according to any one of claims 1 to 3, characterized in that: The fibers in the fiber layer include at least one of the following materials: aramid, PI fiber, PBO fiber, LCP fiber, quartz fiber and carbon fiber; And / or the substrate includes at least one of the following materials: polyimide, silicone rubber and epoxy resin.

6. The optical cable according to any one of claims 1 to 3, characterized in that: The particle size of the hydrogen absorbing material is less than 50 microns.

7. The optical cable according to any one of claims 1 to 3, characterized in that: The optical fiber includes a coating layer; preferably, the coating layer is a high temperature resistant coating layer; further preferably, the coating layer includes at least one of an acrylic resin coating layer, a silicone rubber coating layer, a polyimide coating layer or a carbon coating layer.

8. An optical cable, characterized in that: include: optical fiber; The optical fiber is replaced by the optical cable according to any one of claims 1 to 7.

9. A method for preparing the optical cable according to any one of claims 1 to 7, characterized in that: The steps include: A substrate and a hydrogen absorbing material are mixed and then coated on an optical fiber to obtain a composite coating; or at least one layer of substrate and at least one layer of hydrogen absorbing material are alternately coated on an optical fiber, and a layer of substrate is coated on the outermost layer to obtain a composite coating; the pressure range during coating is 2 to 10 atmospheres, and the temperature range is 25° C. to 80° C.; the weight proportion of the hydrogen absorbing material in the composite coating ranges from 0.2% to 25%; The composite coating is cured to obtain an optical cable.

10. The method according to claim 9, characterized in that Also includes: Before, during or after coating the substrate and the hydrogen absorbing material on the optical fiber, wrapping a plurality of fibers around at least one of the optical fiber, the optical fiber having at least one partial thickness composite coating or the optical fiber having a complete composite coating along the length extension direction of the optical fiber to obtain a fiber layer; The composite coating is solidified, specifically, after the fiber layer and the composite coating are prepared on the periphery of the optical fiber, the composite coating is solidified to obtain an optical cable.

Images