Manufacturing method of low-temperature hose

Abstract

The invention discloses a manufacturing method of a low-temperature hose. The low-temperature hose is manufactured through the following steps that firstly, a metal spiral coil is pressed; 2, annealing and shaping; 3, winding an inner coil; step 4, placing the sheath; and 5, winding the middle layer. The coil is fixed by adopting a mode of firstly pressing and then annealing and shaping, then the protective layer is additionally arranged and the coil is wound, and the deviation of the inner pipe diameter and the outer pipe diameter on each section is greatly reduced through pre-shaping instead of direct winding forming, so that the corrugation at the inlet of the corrugated hose can cause the change of the wall surface shearing force and generate a disturbance effect; the fluid at the inlet of the corrugated hose simulation area has the phenomena of backflow and flow resistance, so that the stability of the low-temperature hose in the use process is greatly influenced.

Description

Technical Field

[0001] The invention relates to the field of cryogenic transportation equipment, and in particular to a method for manufacturing a cryogenic hose. Background Art

[0002] Liquefied natural gas (LNG) cryogenic hose is a key equipment for transporting liquefied natural gas under low temperature conditions. It has the characteristics of good flexibility, strong corrosion resistance and excellent thermal insulation performance. Generally, the LNG cryogenic hose consists of an inner coil, an outer coil and at least one slender sheath, which together constitute the basic structure of the hose. The LNG cryogenic hose has good flexibility and can adapt to the large deformation caused by ocean currents, floating ship movement and installation, thereby ensuring reliability in harsh sea conditions. In addition, the LNG cryogenic hose has strong corrosion resistance and excellent thermal insulation performance. Common cryogenic hoses include metal bellows and non-metallic hoses. However, the LNG corrugated hose in the prior art is usually formed by directly winding the forming coil, resulting in poor consistency of the various parts of the overall pipe body, causing the corrugation at the inlet of the corrugated hose to cause changes in the wall shear force, resulting in a disturbance effect, and the fluid at the inlet of the corrugated hose simulation area will have reflux and flow resistance, which greatly affects the stability of the cryogenic hose during use. Summary of the invention

[0003] The technical problem to be solved by the present invention is how to improve the overall stability of the interior of the cryogenic hose. In view of the above technical problem to be solved, a method for manufacturing a cryogenic hose is now proposed.

[0004] To achieve the above object, the present invention provides the following technical solution: a method for manufacturing a cryogenic hose, wherein the cryogenic hose is manufactured by the following steps:

[0005] Step 1: Metal spiral coil pressing;

[0006] The stainless steel wire is wound into the required inner and outer spiral shapes by a winding machine, and the winding tooling is removed together with the metal spiral coil;

[0007] Step 2: annealing and shaping;

[0008] The tooling and the metal spiral coil are pressed into the annealing furnace, annealed at 350℃-450℃, and naturally cooled to room temperature after annealing;

[0009] Step 3, inner coil winding;

[0010] The annealed inner metal spiral coil is placed on a rotatable mandrel, and the mandrel is started to rotate the inner coil to form a tubular skeleton. The dimensional consistency of each segment is checked by rotation to ensure that it is within the error range;

[0011] Step 4, sheath placement;

[0012] A PTFE tubular sheath is placed longitudinally around the inner metal coil to form an air barrier;

[0013] Step 5, middle layer winding;

[0014] A protective layer, an air-proof layer, a reinforcing layer, a flexible vacuum layer, a reinforcing layer, an air-proof layer and a protective layer are sequentially wound around the outside of the PTFE sheath to form a complete tube wall structure;

[0015] Step 6: Winding the outer coil;

[0016] An outer metal spiral coil is wound around the outside of the tube wall so that it is staggered with the inner coil to form a corrugated structure and achieve self-locking, thus completing the production of the cryogenic hose.

[0017] Furthermore, the metal spiral coil in the step 1 is wound by a flat winding machine.

[0018] Furthermore, the metal spiral coil in the step 1 is wound by a three-dimensional winding machine.

[0019] Furthermore, the metal spiral coil in step 1 is pressed using 316 stainless steel.

[0020] Furthermore, the method further comprises a welding step, in which adjacent low-temperature hoses are welded together, and arc angle treatment is adopted at the welding points.

[0021] Furthermore, the inner diameter of the inner spiral metal spiral coil in step one is 110-112 mm, and the outer diameter of the outer spiral metal spiral coil is 134-136 mm.

[0022] Furthermore, the protective layer and the air-proof layer are fluorine-containing polymer film layers, and the fluorine-containing polymer is a polytetrafluoroethylene film, a polyvinylidene fluoride film or a polychlorotrifluoroethylene film.

[0023] Furthermore, the reinforcement layer is a polyolefin film, a polyester film or a polyester fiber braid.

[0024] Furthermore, the flexible vacuum layer is composed of an aerogel felt and a film bag wrapped outside the aerogel felt, and a vacuum treatment is performed between the aerogel felt and the film bag.

[0025] Furthermore, the anti-air permeability layer is provided with multiple layers.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention solidifies the coil by pressing first and then annealing and shaping, and then adds a protective layer and winds it. Through pre-shaping rather than direct winding, the deviation of the inner and outer pipe diameters in each section is greatly reduced, so that the corrugations at the inlet of the corrugated hose will cause changes in the wall shear force and produce a disturbance effect. The fluid at the inlet of the corrugated hose simulation area will have backflow and flow resistance, which greatly affects the stability of the low-temperature hose during use. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the method flow of the present invention. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe 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 creative work are within the scope of protection of the present invention.

[0030] See also Figure 1 As shown, this specific embodiment discloses a method for manufacturing a cryogenic hose, and the cryogenic hose is manufactured by the following steps:

[0031] Step 1: Metal spiral coil pressing;

[0032] The stainless steel wire is wound into the required inner and outer spiral shapes by a winding machine, and the winding tooling is removed together with the metal spiral coil. It is feasible and preferred that the metal spiral coil is wound by a flat winding machine or a three-dimensional winding machine. Winding by machine can greatly improve efficiency and ensure product consistency.

[0033] Step 2: annealing and shaping;

[0034] The tooling together with the metal spiral coil is pressed into the annealing furnace and annealed at a temperature of 350°C-450°C. After annealing, it is naturally cooled to room temperature.

[0035] This is because, when the annealing temperature is high, the atoms of the material obtain enough energy to migrate and rearrange, which is conducive to the growth of grains. Larger grains usually reduce the hardness and strength of the material, but may improve toughness and plasticity. For example, in the annealing of steel, if the temperature is too high, it will cause the austenite grains to be coarse, and then after cooling, a coarse pearlite structure will be obtained, which will deteriorate the mechanical properties of the steel.

[0036] At a lower annealing temperature, the atomic activity is relatively weak, and the growth of grains is inhibited, so finer grains can be obtained. Fine grains can improve the strength and hardness of the material, but may reduce toughness and plasticity.

[0037] At lower annealing temperatures, the material mainly undergoes a recovery process. At this point, lattice distortion is gradually eliminated, internal stress is released, but the shape and size of the grains remain essentially unchanged. This stage can restore the material's plasticity and toughness while maintaining a certain strength.

[0038] As the annealing temperature increases and reaches the recrystallization temperature, new grains begin to nucleate and grow in the deformed structure, replacing the original deformed grains. The recrystallization process can make the material structure more uniform, eliminate the work hardening effect, and restore the plasticity and toughness of the material.

[0039] If the annealing temperature continues to increase or the holding time is too long, the recrystallized grains will grow further, resulting in grain coarsening. This may have an adverse effect on the performance of the material, such as reducing strength and hardness.

[0040] Direct winding will cause the stress of the material itself to cause the size difference of each coil part. When the difference is too large, it will lead to the size difference between the inside and outside of the pipe, causing the data simulation during design to be distorted, resulting in fluctuations in each size change segment. After annealing at medium and low temperatures, the material stress is eliminated during the annealing process, so that the size of each section of the coil can remain relatively consistent after the tooling is removed, thereby greatly reducing the internal fluctuation caused by size changes. At the same time, it avoids the reduction of structural strength caused by high temperature annealing.

[0041] Step 3, inner coil winding;

[0042] The inner coil is the core part of the LNG cryogenic hose and is usually made of high-strength materials to withstand internal pressure and external loads.

[0043] In this application, the annealed inner metal spiral coil is placed on a rotatable mandrel, the mandrel is started to rotate the inner coil to form a tubular skeleton, and the dimensional consistency of each segment is checked by rotation to ensure that it is within the error range; specifically, the measurement process is to insert a fixed-size tool into the coil, and the dimensional consistency measurement result is obtained by the fit of each segment. Step 4: Place the sheath;

[0044] A PTFE tubular sheath is placed around the inner metal coil in the longitudinal direction to form an air barrier; PTFE, the full name of which is polytetrafluoroethylene, is also often called Teflon, Teflon or the king of plastics. It is a polymer compound with excellent high and low temperature resistance (can be used continuously for a long time in the temperature range of -196°C to 260°C), corrosion resistance (inert to most chemicals and solvents), aging resistance, non-adhesion and low friction coefficient. The size of the sheath used is slightly larger than the inner metal coil. As a preferred method, during the installation process, the inner metal coil can be first covered on a fixed long tubular tooling, and the PTFE tubular sheath can be covered on the inner metal coil after both ends are fixed.

[0045] Step 5, middle layer winding;

[0046] A protective layer, an airtight layer, a reinforcing layer, a flexible vacuum layer, a reinforcing layer, an airtight layer and a protective layer are sequentially wound around the outside of the PTFE sheath to form a complete tube wall structure; preferably, the protective layer and the airtight layer are fluorine-containing polymer film layers, and the fluorine-containing polymer is a polytetrafluoroethylene film, a polyvinylidene fluoride film or a polychlorotrifluoroethylene film.

[0047] Wherein, the reinforcing layer is a polyolefin film, a polyester film or a polyester fiber braid.

[0048] The flexible vacuum layer is composed of an aerogel felt and a film bag wrapped outside the aerogel felt, and a vacuum process is performed between the aerogel felt and the film bag.

[0049] Preferably, the air-proof layer is provided with multiple layers to increase the sealing performance of the pipeline.

[0050] Step 6: Winding the outer coil;

[0051] The outer metal spiral coil is wound on the outside of the pipe wall, so that it is staggered with the inner coil to form a corrugated structure and achieve self-locking, thus completing the production of the low-temperature hose. It is feasible that before winding, the inner coil and the outer coil are matched in size, and winding from both ends can achieve self-locking.

[0052] More preferably, in the present method, the metal spiral coil is pressed using 316 stainless steel.

[0053] In order to further improve the applicability of the product, the hose also includes a welding step, in which adjacent low-temperature hoses are welded together by welding coils, etc., and arc angle treatment is adopted at the welding points.

[0054] Preferably, the inner diameter of the inner spiral metal spiral coil in step one is 110-112 mm, and the outer diameter of the outer spiral metal spiral coil is 134-136 mm.

[0055] The present invention solidifies the coil by pressing first and then annealing and shaping, and then adds a protective layer and winds it. Through pre-shaping rather than direct winding, the deviation of the inner and outer pipe diameters in each section is greatly reduced, so that the corrugations at the inlet of the corrugated hose will cause changes in the wall shear force and produce a disturbance effect. The fluid at the inlet of the corrugated hose simulation area will have backflow and flow resistance, which greatly affects the stability of the low-temperature hose during use.

[0056] In the description of the present invention, it is necessary to understand that the terms "coaxial", "bottom", "one end", "top", "middle", "the other end", "upper", "one side", "top", "inside", "front", "center", "both ends" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0057] In the present invention, unless otherwise clearly stipulated and limited, the terms such as "installation", "setting", "connection", "fixation" and "screw-on" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0058] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations of these embodiments are made without departing from the principles and spirit of the present invention, and still fall within the scope of protection of the present invention.

Claims

1. A method for manufacturing a cryogenic hose, characterized in that: The cryogenic hose is manufactured through the following steps: Step 1: Metal spiral coil pressing; The stainless steel wire is wound into the required inner and outer spiral shapes by a winding machine, and the winding tooling is removed together with the metal spiral coil; Step 2: annealing and shaping; The tooling and the metal spiral coil are pressed into the annealing furnace, annealed at 350℃-450℃, and naturally cooled to room temperature after annealing; Step 3, inner coil winding; The annealed inner metal spiral coil is placed on a rotatable mandrel, and the mandrel is started to rotate the inner coil to form a tubular skeleton. The dimensional consistency of each segment is checked by rotation to ensure that it is within the error range; Step 4, sheath placement; A PTFE tubular sheath is placed longitudinally around the inner metal coil to form an air barrier; Step 5, middle layer winding; A protective layer, an air-proof layer, a reinforcing layer, a flexible vacuum layer, a reinforcing layer, an air-proof layer and a protective layer are sequentially wound around the outside of the PTFE sheath to form a complete tube wall structure; Step 6: Winding the outer coil; An outer metal spiral coil is wound around the outside of the tube wall so that it is staggered with the inner coil to form a corrugated structure and achieve self-locking, thus completing the production of the cryogenic hose.

2. The method for manufacturing a cryogenic hose according to claim 1, characterized in that: The metal spiral coil in the step 1 is wound by a flat winding machine.

3. The method for manufacturing a cryogenic hose according to claim 1, characterized in that: The metal spiral coil in the step 1 is wound by a three-dimensional winding machine.

4. The method for manufacturing a cryogenic hose according to claim 1, characterized in that: The metal spiral coil in the step 1 is pressed using 316 stainless steel.

5. The method for manufacturing a cryogenic hose according to claim 1, characterized in that: The method also includes a welding step, in which adjacent low-temperature hoses are welded together, and arc angle treatment is adopted at the welding points.

6. The method for manufacturing a cryogenic hose according to claim 1, characterized in that: The inner diameter of the inner spiral metal spiral coil in step one is 110-112 mm, and the outer diameter of the outer spiral metal spiral coil is 134-136 mm.

7. The method for manufacturing a cryogenic hose according to claim 1, characterized in that: The protective layer and the air-proof layer are fluorine-containing polymer film layers, and the fluorine-containing polymer is a polytetrafluoroethylene film, a polyvinylidene fluoride film or a polychlorotrifluoroethylene film.

8. The method for manufacturing a cryogenic hose according to claim 1, characterized in that: The reinforcing layer is a polyolefin film, a polyester film or a polyester fiber braid.

9. The method for manufacturing a cryogenic hose according to claim 1, characterized in that: The flexible vacuum layer is composed of an aerogel felt and a film bag wrapped outside the aerogel felt, and a vacuum process is performed between the aerogel felt and the film bag.

10. The method for manufacturing a cryogenic hose according to claim 1, characterized in that: The air-proof layer is provided with multiple layers.

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