Aramid umbilical cable armored structure and production method thereof

Abstract

The invention discloses an aramid umbilical cable armor structure and a production method thereof. The aramid umbilical cable armor structure comprises: N aramid armor layers sequentially arranged on the outside of a cable core from the inside to the outside, and also comprises paraffin wax and N non-woven fabric layers. The non-woven fabric layers correspond to the aramid armor layers one by one, and the non-woven fabric layers are respectively wrapped around the outside of the corresponding aramid armor layers. The paraffin wax is coated on each aramid armor layer and infiltrates the corresponding aramid armor layer and non-woven fabric layer. The aramid armor layer is wrapped by the non-woven fabric layer, which can not only realize the bundling of the aramid armor layers, enhance the consistency of the aramid in the same layer, and improve the output efficiency, but also isolate the aramid between different layers. In addition, the lubrication of the paraffin wax reduces the friction between the aramids, and enhances the breaking force value and bending fatigue performance.

Description

Technical Field

[0001] The present invention relates to the technical field of aramid umbilical cables, in particular to an aramid umbilical cable armored structure and a production method thereof. Background Art

[0002] As a key component of underwater control systems, umbilical cable systems are the "nerve and lifeline" connecting surface platform facilities and underwater production systems. With the continuous advancement of deep-sea exploration, umbilical cables are also developing in the direction of greater depths, ultra-deep waters, and even full ocean depths. The development of seabed development and mining, in particular, places greater demands on stronger, lighter, and more reliable umbilical cables.

[0003] Due to the heavy weight of steel wire armored underwater special optoelectronic composite cables, when the water depth exceeds 5000m, the increase in steel wire strength conflicts with the increase in self-weight with diving depth, and balance cannot be achieved. Therefore, in order to reduce the self-weight, the steel wire armor of heavy deep-sea umbilical cables turns to high-strength non-metallic fiber armor. Among them, high-strength non-metallic fiber armored cables such as aramid and LCP are gradually used in the umbilical cable field due to their light weight and high strength.

[0004] There are also problems with non-metallic fiber armor. When the amount of non-metallic fiber exceeds hundreds of thousands of dtex, a large amount of fiber armor is required. The output consistency of large-count fibers varies greatly, which reduces the output efficiency.

[0005] The methods commonly used in the industry to increase the overall consistency of aramid include dipped aramid and aramid rods. Glue is used in the production process to increase the adhesion between the sheath and the aramid. These methods have a certain effect in improving the breaking force. However, the use of these methods increases the overall stiffness of the aramid reinforcement layer, resulting in a decrease in the relative slippage inside the aramid during stress and bending, an increased risk of stress concentration, and local bending during use, which reduces the overall strength and insufficient resistance to bending fatigue.

[0006] During the use of aramid umbilical cables, the friction between the aramid fibers also reduces the strength of use and needs to be improved. Summary of the Invention

[0007] The main technical problem solved by the present invention is to provide an aramid umbilical cable armor structure and a production method thereof, so as to improve the output consistency between fibers, take into account the bending fatigue performance, and reduce the friction between aramid fibers.

[0008] In order to solve the above technical problems, a technical solution adopted by the present invention is: to provide an aramid umbilical cable armor structure, comprising: N layers of aramid armor layers arranged on the outside of the cable core from the inside to the outside, and also comprising paraffin wax and N layers of non-woven fabric layers, the non-woven fabric layers corresponding to the aramid armor layers one by one, and the non-woven fabric layers are respectively wrapped around the outside of the corresponding aramid armor layers, the paraffin wax is coated on each layer of aramid armor layer, and infiltrates the corresponding aramid armor layer and non-woven fabric layer.

[0009] In a preferred embodiment of the present invention, the cable core includes an inner sheath and optical fiber units and conductors located in the inner sheath.

[0010] In a preferred embodiment of the present invention, the aramid armor layer is armored on the outside of the inner sheath.

[0011] In a preferred embodiment of the present invention, the aramid umbilical cable further includes an outer sheath, and the outer sheath is arranged on the outside of the Nth non-woven fabric layer.

[0012] In a preferred embodiment of the present invention, N is not less than 2.

[0013] In order to solve the above technical problems, another technical solution adopted by the present invention is to provide a method for producing an aramid umbilical cable armor structure, comprising the following steps:

[0014] A. Paying off the cable core:

[0015] Pay off the cable core and aramid, adjust the payoff speed and tension, and set the payoff tension of the twisted aramid (about 60,000 dtex) to tighten the aramid. The payoff tension range is 8-10 kg, which can maintain the synchronous stretching of different aramid strands after armoring. The aramid is armored to the outside of the cable core through the armoring equipment to form an aramid armor layer.

[0016] B. Paraffin coating: Use a hot melt adhesive machine to melt the paraffin, use a pressure pump to extract the liquid paraffin, and transfer it to the paraffin mold through an insulated pipe. The liquid paraffin is coated on the surface of the aramid armor layer passing through the paraffin mold;

[0017] C. Non-woven fabric winding: Using a wrapping device, wrap non-woven fabric around the surface of the paraffin-coated aramid armor layer, tightening the aramid armor layer to form a non-woven fabric layer. Add a heating device to heat the non-woven fabric layer passing through the heating device, so that the paraffin wax melts again, better infiltrating the aramid and non-woven fabric, and enhancing the interlayer lubrication between the non-woven fabric layer and the aramid armor layer;

[0018] D. Armoring the Nth aramid armor layer: Through the above steps, the Nth aramid armor layer is armored on the outside of the N-1th non-woven fabric layer, and after coating with paraffin wax, the Nth non-woven fabric layer is wound and heated to form an armor structure having N layers of aramid armor layers;

[0019] By adjusting the tension of the armor, the outer aramid armor layer is tightened, and the non-woven fabric layer is used for wrapping and paraffin wax is used for lubrication to enhance the consistency of the aramid in the same layer. At the same time, the aramid between different layers is kept well lubricated to reduce wear.

[0020] E. Take-up: Pull the cable core and evenly arrange the armored cable core on the reel of the take-up rack;

[0021] First, the wheel tractor is used to provide traction, and then the crawler tractor is used for traction to isolate the take-up frame and the wheel tractor.

[0022] In a preferred embodiment of the present invention, the heating device comprises a heating jacket.

[0023] The beneficial effects of the present invention are as follows: an aramid umbilical cable armor structure and a production method thereof are pointed out by the present invention, in which the aramid armor layer is wrapped by a non-woven fabric layer, which can not only realize the bundling of the aramid armor layer, enhance the consistency of the aramid in the same layer, and improve the output efficiency, but also isolate the aramid between different layers. In addition, the lubrication of paraffin reduces the friction between the aramids, enhances the breaking force and bending fatigue performance, and is suitable for the production of aramid umbilical cables with large water depth and large load. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work, among which:

[0025] Figure 1 It is a structural schematic diagram of an aramid umbilical cable armor structure of the present invention;

[0026] Figure 2 It is a schematic diagram of a production line adopted in a method for producing an aramid umbilical cable armored structure of the present invention. DETAILED DESCRIPTION

[0027] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] Analysis of factors affecting the strength and bending performance of aramid armored cables:

[0029] Strength analysis

[0030] The strength formula of aramid armored cable is:

[0031]

[0032] i is the number of armor layers;

[0033] M i is the linear density of the i-th layer of armor;

[0034] E is the elastic modulus of armor fiber;

[0035] α i is the angle of the i-th layer fiber armor;

[0036] ρ is the fiber density;

[0037] ε is the online tensile strain;

[0038] μ is the output coefficient;

[0039] For aramid armored cables, since the material properties are fixed, E, ρ, and ε are fixed, and α i For umbilical cables, the angle is usually within a fixed range, so the only factors that can improve the strength are i and M. i 、μ.

[0040] Improve i and M i This will increase the overall amount of aramid used, increase the outer diameter, increase the cost of the finished product, and require a larger winch and space, significantly increasing the cost of the entire system. At the same time, more aramid will reduce the output efficiency, which is often not feasible. Therefore, the industry has focused on the output coefficient μ.

[0041] The output coefficient of large-count aramid is low, usually below 70%, or even below 50%.

[0042] There are several reasons:

[0043] 01. Aramid armor usually uses aramid wires of hundreds of thousands of dtex. When used in large quantities, the fiber filaments are equivalent to a large number of re-parallel lines, and the lengths of different internal lines are inconsistent, resulting in a low output coefficient;

[0044] 02. Different aramid threads have different tightness and elongation after being stressed, which increases the friction between the threads and forms internal stress concentration.

[0045] 03. Unstable tension during the armoring process can also cause the aramid wire to loosen, but current equipment can usually overcome this problem.

[0046] To address the above-mentioned problems with high-count aramid armor, the commonly used methods in the industry are:

[0047] 01. The method of increasing the rigidity of aramid is similar to the steel wire form. The output coefficient of steel wire armor can reach more than 90%, such as aramid rod form and dipped aramid form;

[0048] 02. Improve the bonding strength between different aramid armor layers and between aramid and sheath, and strive for synchronization between cable structure and aramid under tension, usually by glue coating.

[0049] The above method can indeed achieve an improvement in the output coefficient and increase the breaking force, but the increase in stiffness brings about a decrease in bending performance.

[0050] Analysis of the influence of bending fatigue

[0051] 01. Influence of bending outer diameter:

[0052] Because when bending, there is a height difference between different parts of the cable and the central axis of the cable, causing the outer side of the cable to stretch and the inner side to compress. When there is no force, the relative slippage inside the cable releases the stress and reduces the deformation. However, when subjected to force, the slippage is affected by frictional resistance, and the stress cannot be released in time, causing the structure to stretch and increasing the friction loss between the fibers. This slippage is repeated for a long time, causing fatigue of the structure and eventually causing the structure to fail.

[0053] 02. Influence of tension: Tension can stretch the cable and at the same time compress the aramid core, making the internal pressure. When the cable is bent, the pulley generates an extrusion force on the cable. This extrusion makes it more difficult for the cable to slip due to bending. The structural deformation caused by bending is not released through slip. Under the combined effect of deformation and tension, the deformation of the internal fibers of the aramid armor layer increases, and the risk of local damage caused by stress concentration increases.

[0054] 03. Cable structure: From a structural point of view, the part close to the center of the cable is less affected by bending, while the outside is more affected. From the material point of view, the armor material with a rigid structure is easier to slip and not easy to bend and deform, but once bent, it will cause irreversible damage, which will reduce the overall performance. The flexible and well-lubricated structure can release stress through slippage, thus having better bending performance.

[0055] Through the above analysis, we found that there is a contradiction when improving strength and bending properties.

[0056] The method of increasing the rigidity of aramid increases the output coefficient, but increases the risk of bending of the aramid structure. The method of increasing the bonding strength between aramid armor layers limits the relative slippage between layers, while making it impossible to evenly distribute the stress, increasing the risk of stress concentration.

[0057] Through the above analysis, the advantages and disadvantages of the existing methods are summarized, and a design scheme that takes into account both the strength and bending performance of aramid armored umbilical cables is proposed.

[0058] See also Figure 1 , embodiments of the present invention include:

[0059] An aramid umbilical cable armor structure includes: N layers of aramid armor layers 100, paraffin wax, and N layers of non-woven fabric layers 200 arranged on the outside of the cable core from the inside to the outside. In this embodiment, the cable core includes an inner sheath 300 and optical fiber units and conductors located in the inner sheath 300, and the aramid armor layer 100 is armored on the outside of the inner sheath 300.

[0060] The non-woven fabric layer 200 corresponds to the aramid armor layer 100 one by one, and the non-woven fabric layer 200 is wrapped around the outer side of the corresponding aramid armor layer 100. Paraffin wax is coated on each aramid armor layer 100 and infiltrates the corresponding aramid armor layer 100 and the non-woven fabric layer 200. The non-woven fabric layer 200 is used to bundle the aramid armor layers 100, enhance the consistency of the aramid in the same layer of aramid armor layer 100, improve the output efficiency, and isolate the aramid between different aramid armor layers 100. In addition, the lubrication of paraffin wax reduces the friction between the aramid fibers and enhances the breaking force and bending fatigue performance.

[0061] like Figure 1 As shown, the aramid umbilical cable also includes an outer sheath 400, which is arranged on the outside of the Nth non-woven fabric layer, where N is not less than 2. In this embodiment, N is 3, and a structure of three aramid armor layers 100 and three non-woven fabric layers 200 is adopted. The third non-woven fabric layer is protected by the outer sheath 400, and paraffin is used for lubrication to reduce the adverse effects of the outer sheath 400 on the non-woven fabric layer and the aramid armor layer during bending.

[0062] See also Figure 2 , a method for producing an aramid umbilical cable armored structure, using Figure 2 The production line shown in the figure includes a cable core pay-off frame 1, a first pay-off and take-up balancer 2, multiple armor wrapping assembly devices 16, a wheeled traction wheel 10, a crawler traction machine 11, a second pay-off and take-up balancer 12 and a take-up frame 13, which are placed in sequence according to the process sequence. The armor wrapping assembly device 16 includes a first guide wheel 3, an aramid pay-off frame 4, an armoring device 5, a straightening wheel group 15, a paraffin mold 6, a second guide wheel 7, a wrapping machine 8 and a heating device 9, which are placed in sequence according to the process sequence. A hot melt glue machine 14 is provided on one side of the paraffin mold 6 to provide liquid paraffin for the paraffin mold 6, comprising the following steps:

[0063] A. Paying off the cable core:

[0064] The cable core is paid out through the cable core payout frame 1, and the payout speed and payout tension are adjusted by the first payout balancer 2;

[0065] Aramid pay-off is performed using an aramid pay-off frame 4. The pay-off tension of the twisted aramid (approximately 60,000 dtex) is set to tighten the aramid. The aramid pay-off tension range is 8 to 10 kg, which can maintain the synchronous stretching of different aramid strands after armoring. The cable core is fed into the armoring equipment using a first guide wheel 3. The armoring equipment then armors the aramid onto the outside of the cable core to form an aramid armor layer 100. The cable core is straightened using a straightening wheel assembly 15 after the aramid armor layer 100 is armored.

[0066] In this embodiment, the aramid yarn is twisted in multiple strands. Twisting can improve the overall strength of the aramid yarn and make the appearance more regular and reduce burrs.

[0067] B. Paraffin coating: A hot melt adhesive machine 14 is used to melt paraffin. Liquid paraffin is extracted using a pressure pump and transferred to the paraffin mold 6 through an insulated pipe. The liquid paraffin is then coated on the surface of the aramid armor layer 100 passing through the paraffin mold 6. The liquid paraffin is pre-cooled and solidified on the aramid armor layer 100.

[0068] C. Non-woven fabric winding: The cable core is fed into the wrapping device 8 by the second guide pulley 7. The non-woven fabric is wrapped around the surface of the paraffin-coated aramid armor layer 100 by the wrapping device 8. The aramid armor layer 100 is tightly tied to form a non-woven fabric layer 200. The non-woven fabric layer 200 passing through the heating device 9 is heated by the heating device 9. In this embodiment, the heating device includes a heating sleeve. The non-woven fabric layer 200 passes through the heating sleeve and is heated 360 degrees. The paraffin on the aramid armor layer 100 is melted again, which better infiltrates the aramid and non-woven fabric, and enhances the lubrication between the non-woven fabric layer 200 and the aramid armor layer 100.

[0069] The non-woven fabric used as the binding material can round off each aramid armor layer 100, enhancing the structural stability. The gaps between the fibers in the non-woven fabric can also be impregnated with paraffin wax. Paraffin wax is a lubricant. When applied to the surface of an object, it forms a lubricating film, reducing the friction of the surface. Moreover, the paraffin wax becomes a solid structure after cooling, which ensures stable performance.

[0070] In this embodiment, the non-woven fabric is a nylon fiber non-woven fabric with a thickness of 0.2 to 0.4 mm and a wrapping overlap ratio of 25% to 35%, ensuring 100% coverage of the aramid armor layer 100. Nylon has excellent mechanical properties and is oil-resistant, heat-resistant, and wear-resistant, and has a low friction coefficient. The gaps between the fibers facilitate the infiltration of paraffin, thereby further reducing friction.

[0071] D. Armoring the Nth aramid armor layer: Through the above steps, the Nth aramid armor layer is armored on the outside of the N-1th non-woven fabric layer, and after coating with paraffin wax, the Nth non-woven fabric layer is wound and heated to form an armor structure having N layers of aramid armor layers;

[0072] By adjusting the tension of the armor, the outer aramid armor layer 100 is tightened, and the non-woven fabric layer 200 is used for wrapping and lubricating with paraffin wax to enhance the consistency of the aramid fibers in the same layer of the aramid armor layer 100. At the same time, the aramid fibers between different aramid armor layers 100 are well lubricated, reducing wear problems.

[0073] Using high-count twisted aramid as the armor reinforcement material, wrapping non-woven fabric between layers, and adhering paraffin wax on the surface can enhance the output consistency and strength of the aramid in the same layer, reduce the friction between different layers, make the structure round, and facilitate the retraction and uniform extrusion of the outer sheath, so as to achieve the purpose of improving the strength and bending performance of the umbilical cable;

[0074] E. Take-up: Pull the cable core and evenly arrange the armored cable core on the reel of the take-up frame 13. Specifically, first provide traction through the wheel tractor 10, then use the crawler tractor 11 to pull, isolate the take-up frame 13 and the wheel tractor 10, and finally pass through the second take-up and pay-out balancer 12 before taking up the cable through the take-up frame 13.

[0075] In summary, the aramid umbilical cable armor structure and production method thereof pointed out in the present invention can effectively improve the overall output coefficient of the armored aramid of the aramid umbilical cable, increase the breaking force, and at the same time reduce the friction damage of the aramid between different layers during bending, thereby enhancing the bending performance.

[0076] The above are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for producing an aramid umbilical cable armored structure, used for producing an aramid umbilical cable armored structure, wherein the aramid umbilical cable armored structure is armored on the outside of the cable core of the aramid umbilical cable, the aramid umbilical cable armored structure comprising paraffin wax, N non-woven fabric layers, and N aramid armor layers sequentially arranged on the outside of the cable core from the inside to the outside, the non-woven fabric layers corresponding to the aramid armor layers one by one, and the non-woven fabric layers are respectively wrapped around the outside of the corresponding aramid armor layers, the paraffin wax is coated on each layer of the aramid armor layer and infiltrates the corresponding aramid armor layer and non-woven fabric layer, the cable core comprises an inner sheath and an optical fiber unit and a conductor located in the inner sheath, characterized in that: The following steps are involved: A. Paying off the cable core: Pay off the cable core and aramid, and use armoring equipment to armor the aramid to the outside of the cable core to form an aramid armor layer; B. Paraffin coating: melt the paraffin and transfer it to the paraffin mold through an insulated pipe, and apply the liquid paraffin to the surface of the aramid armor layer passing through the paraffin mold; C. Non-woven fabric winding: Using a wrapping device, wrap non-woven fabric around the surface of the paraffin-coated aramid armor layer, tightening the aramid armor layer to form a non-woven fabric layer. Add a heating device to heat the non-woven fabric layer passing through the heating device, so that the paraffin wax melts again, better infiltrating the aramid and non-woven fabric, and enhancing the interlayer lubrication between the non-woven fabric layer and the aramid armor layer; D. Armoring the Nth aramid armor layer: Through the above steps, the Nth aramid armor layer is armored on the outside of the N-1th non-woven fabric layer, and after coating with paraffin wax, the Nth non-woven fabric layer is wound and heated to form an armor structure having N layers of aramid armor layers; E. Take-up: Pull the cable core and arrange the armored cable core evenly on the reel of the take-up rack.

2. The method for producing an aramid umbilical cable armored structure according to claim 1, characterized in that: The heating device includes a heating jacket.

3. The method for producing an aramid umbilical cable armored structure according to claim 1, wherein: The aramid armor layer is armored on the outside of the inner sheath.

4. The method for producing an aramid umbilical cable armored structure according to claim 1, wherein: The aramid umbilical cable further includes an outer sheath, which is arranged on the outside of the Nth non-woven fabric layer.

5. The method for producing an aramid umbilical cable armored structure according to claim 1, wherein: The N is not less than 2.

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