Double-layer metal flexible connecting pipe and manufacturing process

Abstract

The invention discloses a double-layer metal flexible connecting pipe and a manufacturing process, and belongs to the technical field of pipeline connection, the double-layer metal flexible connecting pipe comprises an outer armor, an inner armor is nested in the outer armor, a plurality of buffer mechanisms are nested between the outer armor and the inner armor, and the buffer mechanisms are arranged along the outer armor and the inner armor in an array mode. Contact friction between the outer armor and the inner armor is reduced through the buffer mechanism, an inner soft layer is arranged in the inner armor, and a protective coating is arranged in the inner soft layer. According to the invention, a buffer mechanism composed of the flexible ring, the ball groove, the gasket and the ball is arranged, so that the outer armor and the inner armor are supported through point contact and rolling contact of the ball, large-area direct friction does not occur between the two layers of armor in the bending, twisting or vibrating process, the abrasion loss is obviously reduced, and the durability of the product is improved. And the array arrangement of the buffer mechanism can also uniformly disperse external loads, and the overall flexibility is improved.

Description

Technical Field

[0001] This invention belongs to the field of pipeline connection technology, and particularly relates to a double-layer metal flexible connection pipe and its manufacturing process. Background Technology

[0002] Metal flexible conduits are widely used in flexible fluid transport systems, such as high-temperature fluid transport, flexible equipment connections, mechanical vibration isolation, and electromagnetic shielding pipelines. Metal flexible conduits typically consist of an outer metal braided layer and an inner metal flexible hose, which work together to achieve pressure resistance, bending resistance, and a certain degree of flexibility. However, as application scenarios increasingly demand flexibility, wear resistance, and service life, the traditional structure has gradually revealed several problems.

[0003] Traditional outer and inner armor directly contact and rub against each other. Under long-term bending, vibration or pulsating pressure, high-frequency friction will be generated between the outer braided layer and the inner metal tube. This not only causes metal debris to fall off, but also accelerates wear, shortens the life of the metal hose, and may lead to a decrease in shielding performance or local hardening, affecting flexibility. There is room for improvement. Summary of the Invention

[0004] The purpose of this invention is to provide a double-layer metal flexible connector and its manufacturing process in order to solve the problem of direct contact and friction between the outer armor and the inner armor.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A double-layer metal flexible connector includes an outer armor, an inner armor nested inside the outer armor, and a plurality of buffer mechanisms nested between the outer and inner armors. The buffer mechanisms are arranged in an array along the outer and inner armors to reduce contact friction between the outer and inner armors. The inner armor has an inner soft layer and a protective coating.

[0006] As a further description of the above technical solution: The buffer mechanism includes a flexible ring, which is sleeved on the outer side of the inner armor. Multiple ball grooves are formed around the outer periphery of the flexible ring along the axis. A gasket is embedded in the ball groove, and a ball is rotatably connected in the gasket. The two sides of the ball are in contact with the outer armor and the inner armor respectively. The friction between the outer armor and the inner armor is reduced by the rotation of the ball.

[0007] As a further description of the above technical solution: Adjacent flexible rings are connected by tension ribs, which are elastic ropes.

[0008] As a further description of the above technical solution: The outer armor is a stainless steel woven layer, and the outer armor is coated with a tungsten carbide coating. The outer armor is woven with a diamond-shaped woven layer.

[0009] As a further description of the above technical solution: The inner armor is a spiral corrugated pipe layer.

[0010] As a further description of the above technical solution: The inner soft layer is a polytetrafluoroethylene (PTFE) flexible tube, and the protective coating is a zirconium oxide nano-coating.

[0011] As a further description of the above technical solution: A manufacturing process for a double-layer metal flexible connector tube specifically includes the following steps: S1. Austenitic stainless steel wire is stretched and shaped to the required diameter, ensuring wire diameter tolerance and removing burrs to obtain pre-treated steel wire. The steel wire is chemically degreased and passivated. Polytetrafluoroethylene material is extruded into a hose. The extrusion process temperature is controlled at 360–380°C. After extrusion, vacuum curing is performed for baking and stretching. The hose is cleaned and dried, and its dimensions are inspected. S2, PTFE hose extrusion: PTFE hoses are produced using a high-pressure extruder, with the extrusion temperature controlled at 340°C-360°C, the stretching speed and the cooling water temperature controlled. After extrusion, the hoses are cut to the required length by a cutting machine, and then dried and shaped by infrared or steam. S3. A zirconia nano-coating is uniformly deposited on the inner wall of PTFE by magnetron sputtering. The cleaned PTFE tubing is placed in a rotating fixture in a vacuum chamber, and zirconia is deposited on the target material by stirring magnetron sputtering. The process temperature is controlled below 100–200°C to prevent the PTFE tubing from deforming. Surface roughness and adhesion are tested to ensure uniform coating coverage and no peeling. S4. PTFE and corrugated pipe combination: Slide the PTFE hose coated with zirconium oxide into the prefabricated corrugated pipe. Due to the slight shrinkage of the inner diameter of the corrugated pipe, use medium lubrication during assembly. Slowly rotate the hose into the pipe until the two ends are aligned. Keep the inner wall coating intact and prevent it from falling off. Avoid the tip from scratching the hose. After assembly, mechanically press and fix both ends. S5. Prefabrication and batch assembly of the buffer mechanism: Flexible rings, ball grooves and gaskets are mass-produced through injection molding, casting or stamping processes. Components such as ball groove rings should be surface polished to ensure spherical contact accuracy. Automatic ball feeding device is used to push balls into the ball grooves in sequence for automatic assembly. After each buffer unit is assembled, the assembly machine uses a micro robot arm to put the flexible ring and gasket into the outer circumference of the bellows and locks them with a clamp. Visual inspection or mechanical limit sensors are used for real-time verification. Only after confirming that the ball grooves, springs and other components are correctly in place can the next step be continued. S6. Use a multi-spindle braiding machine to braid the inner layer. Configure the braiding machine so that the steel wires are wrapped around the inner layer in an interlaced manner. During the braiding process, the steel wires need to be controlled with constant tension. The tension sensor is used to monitor in real time and the tension is adjusted by a servo motor to ensure that the tension of the steel wires is consistent throughout the entire length. After the outer layer is braided, a tungsten carbide coating is sprayed. Tungsten carbide powder is sprayed onto the surface of the braided layer by ion spraying. Stress is eliminated by homogenization heat treatment, and the coating adhesion strength is tested to complete the preparation.

[0012] As a further description of the above technical solution: The braiding machine configured in S6 includes steel wires braided in a diamond pattern.

[0013] As a further description of the above technical solution: The assembly process in S4 uses glycerol as the lubricant.

[0014] As a further description of the above technical solution: The process of spraying tungsten carbide powder onto the surface of the braided layer by ion spraying specifically includes the following steps: S201. Use compressed air or ultrasonic cleaning to clean the surface of the braided layer to remove oil, particles and other impurities. S202. Roughening treatment is carried out by sandblasting, using alumina sand with a particle size of 24~46 mesh, sandblasting pressure of 0.4~0.6 MPa, sandblasting angle of 60~90°, and distance of 100–150 mm, to roughen the surface of stainless steel wire to a surface roughness (Ra) of 4–6 μm. S203. Using a plasma spraying system, the spray gun, plasma power supply, powder feeder, and robotic arm / track spraying platform are protected by argon and hydrogen gases. The powder is WC-Co alloy powder with a particle size of 15~45 μm and a coating thickness of 60–120 μm. S204. Equipment preheating and test spraying: Start the spraying system, preheat the spray gun and stabilize the parameters. First, spray the sample on the test plate and adjust the spraying thickness and uniformity. Move the braided tube slowly through the rotating clamp or linear track, and control the spray gun to scan the tube surface in a spiral trajectory to ensure uniform coverage. After each pass, rotate the hose at a certain angle to cover the next circle. Repeat the scanning multiple times to achieve the target thickness. S205. Cooling and post-treatment: After spraying, allow the coating to cool naturally to room temperature.

[0015] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. In this invention, a buffer mechanism consisting of a flexible ring, ball groove, gasket, and ball bearings is used to support the outer and inner armor layers through point contact and rolling contact of the ball bearings. This prevents large-area direct friction between the two armor layers during bending, torsion, or vibration, significantly reducing wear and improving product durability. The array arrangement of the buffer mechanism can also evenly distribute external loads and improve overall flexibility.

[0016] 2. In this invention, the outer armor adopts a stainless steel diamond-shaped woven structure, which has excellent tensile strength, flexibility and electromagnetic shielding effect. The inner armor adopts a spiral corrugated tube form, which has good radial compressive strength and axial compensation ability, and can achieve a comprehensive balance between flexibility and strength, while enhancing vibration and impact resistance.

[0017] 3. In this invention, the inner soft layer is a PTFE hose, which has an extremely low coefficient of friction and excellent corrosion resistance, making it suitable for conveying highly corrosive, high-purity, and high-cleanliness fluids. Furthermore, the zirconium oxide nano-coating improves wear resistance, anti-fouling properties, and thermal stability, reduces fluid erosion and wear, extends service life, and meets the requirements for high cleanliness and long-term stability of the inner wall. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the hierarchical structure of a double-layer metal flexible connector tube proposed in this invention; Figure 2 This is a schematic diagram of the buffer mechanism structure of a double-layer metal flexible connector tube proposed in this invention; Figure 3 This is a schematic diagram of the lateral structure of the buffer mechanism of a double-layer metal flexible connector tube proposed in this invention; Figure 4 This is a schematic diagram of the manufacturing process of a double-layer metal flexible connector tube proposed in this invention.

[0019] Legend: 1. Outer armor; 2. Inner armor; 3. Buffer mechanism; 4. Inner soft layer; 5. Protective coating; 301. Flexible ring; 302. Ball groove; 303. Gasket; 304. Ball; 305. Connecting rib. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please see Figure 1-4The present invention provides a technical solution: a double-layer metal flexible connector tube, including an outer armor, an inner armor nested inside the outer armor, and a plurality of buffer mechanisms nested between the outer armor and the inner armor. The buffer mechanisms are arranged in an array along the outer armor and the inner armor to reduce the contact friction between the outer armor and the inner armor. The inner armor is provided with an inner soft layer and a protective coating.

[0022] The buffer mechanism includes a flexible ring, which is sleeved on the outer side of the inner armor. Multiple ball grooves are opened around the outer periphery of the flexible ring along the axis. A gasket is embedded in the ball groove, and a ball is rotatably connected in the gasket. The two sides of the ball are in contact with the outer armor and the inner armor respectively. The friction between the outer armor and the inner armor is reduced by the rotation of the ball. Adjacent flexible rings are connected by tension ribs, which are elastic ropes.

[0023] The outer armor is a stainless steel braided layer, the outer armor is coated with a tungsten carbide coating, the outer armor is a diamond-shaped braided layer, the inner armor is a spiral corrugated layer, the inner soft layer is a polytetrafluoroethylene (PTFE) hose, and the protective coating is a zirconium oxide nano-coating.

[0024] Please see Figure 4 A manufacturing process for a double-layer metal flexible connector tube specifically includes the following steps: S1. Austenitic stainless steel wire is stretched and shaped to the required diameter, ensuring wire diameter tolerance and removing burrs to obtain pre-treated steel wire. The steel wire is chemically degreased and passivated. Polytetrafluoroethylene material is extruded into a hose. The extrusion process temperature is controlled at 360–380°C. After extrusion, vacuum curing is performed for baking and stretching. The hose is cleaned and dried, and its dimensions are inspected. S2, PTFE hose extrusion: PTFE hoses are produced using a high-pressure extruder, with the extrusion temperature controlled at 340°C-360°C, the stretching speed and the cooling water temperature controlled. After extrusion, the hoses are cut to the required length by a cutting machine, and then dried and shaped by infrared or steam. S3. A zirconia nano-coating is uniformly deposited on the inner wall of PTFE by magnetron sputtering. The cleaned PTFE tubing is placed in a rotating fixture in a vacuum chamber, and zirconia is deposited on the target material by stirring magnetron sputtering. The process temperature is controlled below 100–200°C to prevent the PTFE tubing from deforming. Surface roughness and adhesion are tested to ensure uniform coating coverage and no peeling. S4. PTFE and corrugated pipe combination: Slide the PTFE hose coated with zirconium oxide into the prefabricated corrugated pipe. Due to the slight shrinkage of the inner diameter of the corrugated pipe, use medium lubrication during assembly. Slowly rotate the hose into the pipe until the two ends are aligned. Keep the inner wall coating intact and prevent it from falling off. Avoid the tip from scratching the hose. After assembly, mechanically press and fix both ends. S5. Prefabrication and batch assembly of the buffer mechanism: Flexible rings, ball grooves and gaskets are mass-produced through injection molding, casting or stamping processes. Components such as ball groove rings should be surface polished to ensure spherical contact accuracy. Automatic ball feeding device is used to push balls into the ball grooves in sequence for automatic assembly. After each buffer unit is assembled, the assembly machine uses a micro robot arm to put the flexible ring and gasket into the outer circumference of the bellows and locks them with a clamp. Visual inspection or mechanical limit sensors are used for real-time verification. Only after confirming that the ball grooves, springs and other components are correctly in place can the next step be continued. S6. Use a multi-spindle braiding machine to braid the inner layer. Configure the braiding machine so that the steel wires are wrapped around the inner layer in an interlaced manner. During the braiding process, the steel wires need to be controlled with constant tension. The tension sensor is used to monitor in real time and the tension is adjusted by a servo motor to ensure that the tension of the steel wires is consistent throughout the entire length. After the outer layer is braided, a tungsten carbide coating is sprayed. Tungsten carbide powder is sprayed onto the surface of the braided layer by ion spraying. Stress is eliminated by homogenization heat treatment, and the coating adhesion strength is tested to complete the preparation.

[0025] The braiding machine configured in S6 includes steel wires braided in a diamond pattern, and the assembly in S4 uses glycerin as the medium lubrication.

[0026] The process of spraying tungsten carbide powder onto the surface of the braided layer by ion spraying specifically includes the following steps: S201. Use compressed air or ultrasonic cleaning to clean the surface of the braided layer to remove oil, particles and other impurities. S202. Roughening treatment is carried out by sandblasting, using alumina sand with a particle size of 24~46 mesh, sandblasting pressure of 0.4~0.6 MPa, sandblasting angle of 60~90°, and distance of 100–150 mm, to roughen the surface of stainless steel wire to a surface roughness (Ra) of 4–6 μm. S203. Using a plasma spraying system, the spray gun, plasma power supply, powder feeder, and robotic arm / track spraying platform are protected by argon and hydrogen gases. The powder is WC-Co alloy powder with a particle size of 15~45 μm and a coating thickness of 60–120 μm. S204. Equipment preheating and test spraying: Start the spraying system, preheat the spray gun and stabilize the parameters. First, spray the sample on the test plate and adjust the spraying thickness and uniformity. Move the braided tube slowly through the rotating clamp or linear track, and control the spray gun to scan the tube surface in a spiral trajectory to ensure uniform coverage. After each pass, rotate the hose at a certain angle to cover the next circle. Repeat the scanning multiple times to achieve the target thickness. S205. Cooling and post-treatment: After spraying, allow the coating to cool naturally to room temperature.

[0027] In this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "multiple" refers to two or more unless otherwise explicitly defined. The terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; "linking" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0028] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A double-layer metal flexible connector, characterized in that, It includes an outer armor, an inner armor nested within the outer armor, and several buffer mechanisms nested between the outer and inner armor. The buffer mechanisms are arranged along the outer and inner armor array to reduce contact friction between the outer and inner armor. The inner armor has an inner soft layer with a protective coating.

2. The double-layer metal flexible connector pipe according to claim 1, characterized in that, The buffer mechanism includes a flexible ring, which is sleeved on the outer side of the inner armor. Multiple ball grooves are formed around the outer periphery of the flexible ring along the axis. A gasket is embedded in the ball groove, and a ball is rotatably connected in the gasket. The two sides of the ball are in contact with the outer armor and the inner armor respectively. The friction between the outer armor and the inner armor is reduced by the rotation of the ball.

3. A double-layer metal flexible connector pipe according to claim 2, characterized in that, Adjacent flexible rings are connected by tension ribs, which are elastic ropes.

4. A double-layer metal flexible connector pipe according to claim 2, characterized in that, The outer armor is a stainless steel woven layer, and the outer armor is coated with a tungsten carbide coating. The outer armor is woven with a diamond-shaped woven layer.

5. A double-layer metal flexible connector pipe according to claim 1, characterized in that, The inner armor is a spiral corrugated pipe layer.

6. A double-layer metal flexible connector pipe according to claim 1, characterized in that, The inner soft layer is a polytetrafluoroethylene (PTFE) flexible tube, and the protective coating is a zirconium oxide nano-coating.

7. A manufacturing process for a double-layer metal flexible connector, characterized in that, The application of a double-layer metal flexible connector tube according to any one of claims 1-6 specifically includes the following steps: S1. Austenitic stainless steel wire is stretched and shaped to the required diameter, ensuring wire diameter tolerance and removing burrs to obtain pre-treated steel wire. The steel wire is chemically degreased and passivated. Polytetrafluoroethylene material is extruded into a hose. The extrusion process temperature is controlled at 360–380°C. After extrusion, vacuum curing is performed for baking and stretching. The hose is cleaned and dried, and its dimensions are inspected. S2, PTFE hose extrusion: PTFE hoses are produced using a high-pressure extruder, with the extrusion temperature controlled at 340°C-360°C, the stretching speed and the cooling water temperature controlled. After extrusion, the hoses are cut to the required length by a cutting machine, and then dried and shaped by infrared or steam. S3. A zirconia nano-coating is uniformly deposited on the inner wall of PTFE by magnetron sputtering. The cleaned PTFE tubing is placed in a rotating fixture in a vacuum chamber, and zirconia is deposited on the target material by stirring magnetron sputtering. The process temperature is controlled below 100–200°C to prevent the PTFE tubing from deforming. Surface roughness and adhesion are tested to ensure uniform coating coverage and no peeling. S4. PTFE and corrugated pipe combination: Slide the PTFE hose coated with zirconium oxide into the prefabricated corrugated pipe. Due to the slight shrinkage of the inner diameter of the corrugated pipe, use medium lubrication during assembly. Slowly rotate the hose into the pipe until the two ends are aligned. Keep the inner wall coating intact and prevent it from falling off. Avoid the tip from scratching the hose. After assembly, mechanically press and fix both ends. S5. Prefabrication and batch assembly of the buffer mechanism: Flexible rings, ball grooves and gaskets are mass-produced through injection molding, casting or stamping processes. Components such as ball groove rings should be surface polished to ensure spherical contact accuracy. Automatic ball feeding device is used to push balls into the ball grooves in sequence for automatic assembly. After each buffer unit is assembled, the assembly machine uses a micro robot arm to put the flexible ring and gasket into the outer circumference of the bellows and locks them with a clamp. Visual inspection or mechanical limit sensors are used for real-time verification. Only after confirming that the ball grooves, springs and other components are correctly in place can the next step be continued. S6. Use a multi-spindle braiding machine to braid the inner layer. Configure the braiding machine so that the steel wires are wrapped around the inner layer in an interlaced manner. During the braiding process, the steel wires need to be controlled with constant tension. The tension sensor is used to monitor in real time and the tension is adjusted by a servo motor to ensure that the tension of the steel wires is consistent throughout the entire length. After the outer layer is braided, a tungsten carbide coating is sprayed. Tungsten carbide powder is sprayed onto the surface of the braided layer by ion spraying. Stress is eliminated by homogenization heat treatment, and the coating adhesion strength is tested to complete the preparation.

8. The manufacturing process of a double-layer metal flexible connector according to claim 7, characterized in that, The braiding machine configured in S6 includes steel wires braided in a diamond pattern.

9. The manufacturing process of a double-layer metal flexible connector according to claim 7, characterized in that, The assembly process in S4 uses glycerol as the lubricant.

10. The manufacturing process of a double-layer metal flexible connector according to claim 7, characterized in that, The process of spraying tungsten carbide powder onto the surface of the braided layer by ion spraying specifically includes the following steps: S201. Use compressed air or ultrasonic cleaning to clean the surface of the braided layer to remove oil, particles and other impurities. S202. Roughening treatment is carried out by sandblasting, using alumina sand with a particle size of 24~46 mesh, sandblasting pressure of 0.4~0.6MPa, sandblasting angle of 60~90°, and distance of 100–150 mm, to roughen the surface of stainless steel wire to a surface roughness (Ra) of 4–6 μm. S203. Using a plasma spraying system, the spray gun, plasma power supply, powder feeder, and robotic arm / track spraying platform are protected by argon and hydrogen gases. The powder is WC-Co alloy powder with a particle size of 15~45 μm and a coating thickness of 60–120 μm. S204. Equipment preheating and test spraying: Start the spraying system, preheat the spray gun and stabilize the parameters. First, spray the sample on the test plate and adjust the spraying thickness and uniformity. Move the braided tube slowly through the rotating clamp or linear track, and control the spray gun to scan the tube surface in a spiral trajectory to ensure uniform coverage. After each pass, rotate the hose at a certain angle to cover the next circle. Repeat the scanning multiple times to achieve the target thickness. S205, Cooling and Post-treatment: After spraying, allow the coating to cool naturally to room temperature.

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