A method for manufacturing a fully wrapped liner-free gas storage cylinder

Abstract

The present invention provides a method for manufacturing a fully wrapped liner-free gas cylinder, comprising the following manufacturing steps: impregnating and coating a high-strength lightweight fiber rope with a thermoplastic slurry to form a composite rope, which is rolled for standby use; feeding the composite rope into the print head of a 3D printer system to longitudinally print the longitudinal winding layer of the bottle body until the main body of the bottle body is formed; filling the main body of the bottle body with an internal pressure of 0.3 to 0.5 MPa through an air injection valve; after the internal pressure is filled, the internal pressure is maintained, and then the composite rope is circumferentially hot-melt-wound on the outer surface of the main body of the bottle body in multiple layers; heating the circumferentially hot-melt-wound bottle body to the softening temperature of the thermoplastic plastic, maintaining the constant temperature for 30 minutes, cooling to room temperature, and then releasing the pressure. The present invention overcomes the shortcomings of Type I, Type II, and Type III gas cylinders due to the excessive weight of the metal liner itself, saves the production cost of the liner, and has the advantages of reducing the transportation and use costs of the gas and the labor intensity.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a gas cylinder, in particular to a method for manufacturing a fully wrapped linerless gas cylinder, and specifically to a method for manufacturing a fully wrapped linerless gas cylinder body by 3D printing using high-strength lightweight fiber as a reinforcing material and thermoplastic plastic as a matrix. Background Art

[0002] Based on existing safe manufacturing materials and processes, gas cylinders are generally divided into four types. Type I (Type I) is a metal cylinder; Type II (Type II) is a metal liner fiber-wound cylinder; Type III (Type III) is a metal liner fiber-wound cylinder; Type IV (Type IV) is a non-metal fiber-wound cylinder. Type I, II, and III cylinders all have the disadvantage of a low capacity / mass (the amount of gas contained and the mass of the cylinder) ratio. Existing Type I, II, and III cylinders all have liners, which are expensive to produce, and there is currently no method for using composite materials to produce fully wrapped liner-free cylinders using a 3D printer.

[0003] Future hydrogen-powered vehicles require lighter and more economical hydrogen storage cylinders, which involve both technical challenges and huge market potential. The manufacturing method of the present invention not only enables the gas storage cylinder to have good mechanical properties and light weight, but also has relatively low material and cost requirements. Summary of the Invention

[0004] The main purpose of the present invention is to provide a method for manufacturing a fully wrapped liner-free gas cylinder, which overcomes the shortcomings of the above-mentioned Type I, Type II, and Type III gas cylinders due to the excessive weight of the metal liner itself, saves the production cost of the liner, and has the advantages of reducing the transportation and use costs and labor intensity of the gas.

[0005] To achieve the above objectives, the present invention proposes a method for manufacturing a fully wrapped linerless gas cylinder, which uses high-strength lightweight fiber rope as a continuous reinforcement material and thermoplastic plastic as a matrix material, and is formed with the aid of 3D printing technology. After the circumferential winding is completed, thermal expansion shaping is adopted to put the reinforcement material in the bottle body into a prestressed state.

[0006] Through stress analysis, we can get:

[0007] Stress of the spherical parts at both ends of the gas cylinder: σ 纵 =pR / 2δ.

[0008] Stress of the cylindrical part of the gas cylinder: σ 环 =pR / δ.

[0009] Among them, σ 纵 , σ 环are the stresses on the spherical and cylindrical parts of the gas cylinder respectively, p is the gas storage pressure, R is the inner diameter of the gas cylinder, and δ is the wall thickness of the gas cylinder.

[0010] These two formulas indicate that the stress on the spherical part of the gas cylinder is half of the stress on the cylindrical part. The present invention fully considers this factor when distributing the longitudinal and circumferential reinforcement materials.

[0011] A method for manufacturing a fully wrapped liner-free gas cylinder is implemented, and the specific manufacturing steps are as follows:

[0012] A. Preparation: Dip and roll a high-strength, lightweight fiber rope with thermoplastic slurry to create a composite rope, which will be used as 3D printing material. Roll the rope and create a cylindrical model for 3D printing in 3D modeling software.

[0013] B. Printing the longitudinal winding layer: importing the round-head cylindrical model into a 3D printer system, setting the print head temperature of the 3D printer system, feeding the composite rope into the print head, and printing the longitudinal winding layer of the gas cylinder longitudinally until the printing is completed to form the main body of the gas cylinder;

[0014] C. Filling the bottle with internal pressure: After the main body of the bottle is placed to cool, install an air injection valve at either end and fill the main body of the bottle with an internal pressure of 0.3-0.5MPa through the air injection valve;

[0015] D. Hoop winding: After the internal pressure is filled, maintain the internal pressure, and then use the composite rope to perform hoop hot-melt winding on the entire longitudinal length of the outer surface of the main body of the bottle in multiple layers;

[0016] E. Thermal expansion shaping: Heat the bottle body after the hoop hot melt wrapping to the softening temperature of the thermoplastic while maintaining the internal pressure, keep the constant temperature for 30 minutes, then cool it naturally to room temperature, and then release the pressure to complete the production of the bottle body.

[0017] Furthermore, the print head discharge temperature of the 3D printer system and the composite rope hot melt winding temperature are set to the free flow temperature of the thermoplastic plastic.

[0018] Furthermore, the high-strength and lightweight fiber rope is made of carbon fiber, glass fiber or bamboo fiber.

[0019] The advantages of this invention lie in that, using composite rope as the printing material, the longitudinal wrapping layers (direction of the bottle's length) are first printed to form the main body of the bottle. Hoop wrapping is then performed. Under internal pressure, multiple layers of composite rope are heat-melted around the entire longitudinal length of the outer surface of the main body to ensure radial strength. While maintaining internal pressure, the bottle is heated to the softening temperature of the thermoplastic and maintained at this temperature for 30 minutes. The temperature is then cooled to room temperature and the pressure is released, prestressing the reinforcing material within the bottle.

[0020] Furthermore, the present invention utilizes a thermoplastic matrix and high-strength, lightweight glass fiber, carbon fiber, or bamboo fiber as reinforcement. Because the elastic deformation of thermoplastic materials is far greater than that of high-strength, lightweight fibers, when the bottle is inflated to high pressure, the tension on the bottle wall is primarily borne by the high-strength, lightweight fibers. By leveraging prestress and elastic deformation, the present invention maximizes the tensile strength of the reinforcement.

[0021] The invention utilizes 3D printing technology to create a fully wrapped bottle without an inner liner, eliminating the cost of inner liner production. The gas cylinder is made of high-strength, lightweight fiber-reinforced composite materials such as glass fiber, carbon fiber, or bamboo fiber, effectively reducing the bottle's own weight.

[0022] The present invention can be used to produce new lightweight, low-cost, high-pressure gas storage cylinders, and can also be applied to other products such as pipes, tanks, and shells that require composite materials. It is widely used in equipment in various fields such as modern transportation, shipping and ocean, aerospace, and chemical industry. DETAILED DESCRIPTION

[0023] Refer to ISO11439-2013 Gas cylinders - High pressure gas cylinders for on-board storage international standard.

[0024] Implementation Method 1

[0025] A 20MPa round-head cylindrical gas storage cylinder was produced with an inner diameter of 300mm and a total length of 800mm.

[0026] The present invention provides a method for manufacturing a fully wrapped liner-free gas storage cylinder, comprising the following steps:

[0027] A. Preparation: Bamboo fiber ropes with diameters of 5 mm and 1 mm, respectively, were dipped and coated with ABS plastic slurry to form composite ropes No. 1 and No. 2. These were rolled and ready for use. The ABS plastic slurry coating thickness was 0.15 mm for each, resulting in a No. 1 composite rope with a diameter of 5.3 mm and a No. 2 composite rope with a diameter of 1.3 mm. The No. 1 composite rope was used as 3D printing material. A 3D-printed cylindrical model was created using 3D modeling software.

[0028] B. Printing the longitudinal wrapping layer: Import the round-head cylindrical model into a 3D printer system, set the print head temperature of the 3D printer system to 170-180°C, feed the No. 1 composite rope into the print head, and print the longitudinal wrapping layer of the gas cylinder along the length direction of the bottle body until printing is completed to form the main body of the gas cylinder body.

[0029] C. Filling the bottle with internal pressure: After the main body of the bottle is placed to cool, install an air injection valve at either end and fill the main body of the bottle with an internal pressure of 0.3MPa through the air injection valve.

[0030] D. Hoop winding: After the internal pressure is filled, maintain the internal pressure, place the main body of the bottle on the hoop hot melt wrapping machine, and use No. 2 composite rope to perform hoop hot melt wrapping (215-220℃) on the outer surface of the main body of the bottle for 10 layers along the entire longitudinal length, with a wrapping angle of 90°.

[0031] E. Thermal expansion shaping: Heat the bottle body after the hoop hot melt wrapping to the softening temperature of ABS plastic in the drying room while maintaining the internal pressure. Keep the constant temperature for 30 minutes, then cool it naturally to room temperature, and then release the pressure to complete the production of the bottle body.

[0032] Implementation Method 2

[0033] A 30MPa round-head cylindrical gas storage cylinder was produced with an inner diameter of 300mm and a total length of 800mm.

[0034] A method for manufacturing a fully wrapped liner-free gas storage cylinder comprises the following steps:

[0035] A. Preparation: 5mm and 1mm diameter glass fiber ropes were dipped and coated with PLA slurry to form composite ropes No. 1 and No. 2, respectively. The PLA slurry coating thickness was 0.15mm for each, resulting in a No. 1 composite rope with a diameter of 5.3mm and a No. 2 composite rope with a diameter of 1.3mm. The No. 1 composite rope was used as 3D printing material. A 3D-printed cylindrical model was created using 3D modeling software.

[0036] B. Printing the longitudinal wrapping layer: Import the round-head cylindrical model into a 3D printer system, set the print head temperature of the 3D printer system to 195-200°C, feed the No. 1 composite rope into the print head, and print the longitudinal wrapping layer of the gas cylinder along the length direction of the bottle body until printing is completed to form the main body of the gas cylinder body.

[0037] C. Filling the bottle with internal pressure: After the main body of the bottle is placed to cool, install an air injection valve at either end and fill the main body of the bottle with an internal pressure of 0.3MPa through the air injection valve.

[0038] D. Hoop winding: After completing the internal pressure filling, maintain the internal pressure, place the main body of the bottle on the hoop hot melt wrapping machine, and use No. 2 composite rope to perform hoop hot melt wrapping (195-200℃) on the outer surface of the main body of the bottle in the entire longitudinal length for 10 layers, with a wrapping angle of 90°.

[0039] E. Thermal expansion shaping: Heat the bottle body after the hoop hot melt wrapping to the softening temperature of PLA plastic in a drying room while maintaining the internal pressure. Keep the constant temperature for 30 minutes, then cool it naturally to room temperature, and then release the pressure to complete the bottle production.

[0040] Implementation 3

[0041] A 70MPa round-head cylindrical gas storage cylinder was produced with an inner diameter of 300mm and a total length of 800mm.

[0042] A method for manufacturing a fully wrapped liner-free gas storage cylinder comprises the following steps:

[0043] A. Preparation: Carbon fiber ropes with diameters of 5 mm and 1 mm, respectively, were dipped and coated with nylon slurry to form composite ropes No. 1 and No. 2. The nylon slurry coating thickness was 0.15 mm. That is, the diameter of composite rope No. 1 was 5.3 mm, and the diameter of composite rope No. 2 was 1.3 mm. Composite rope No. 1 was used as a 3D printing material, and a 3D-printed cylindrical model was created in 3D modeling software.

[0044] B. Printing the longitudinal wrapping layer: The round-head cylindrical model is imported into a 3D printer system. The print head temperature of the 3D printer system is set to 215-220°C. A No. 1 composite rope is fed into the print head. The longitudinal wrapping layer of the gas cylinder is printed along the length direction of the bottle body until printing is completed to form the main body of the bottle body.

[0045] C. Filling with internal pressure: After the main body of the bottle is placed to cool, install an air injection valve at either end and fill the main body of the bottle with an internal pressure of 0.5MPa through the air injection valve.

[0046] D. Hoop winding: After the internal pressure is filled, maintain the internal pressure, place the main body of the bottle on the hoop hot melt wrapping machine, and use No. 2 composite rope to perform hoop hot melt wrapping (215-220℃) on the outer surface of the main body of the bottle for 10 layers along the entire longitudinal length, with a wrapping angle of 90°.

[0047] E. Thermal expansion shaping: Heat the bottle body after the hoop hot melt wrapping to the softening temperature of the nylon material in the drying room while maintaining the internal pressure. Keep the constant temperature for 30 minutes, then cool it naturally to room temperature, and then release the pressure to complete the production of the bottle body.

[0048] Although the specific embodiments of the present invention are described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for manufacturing a fully wrapped liner-free gas cylinder, characterized in that: The production steps are as follows: A. Preparation: Dip and roll a high-strength, lightweight fiber rope with thermoplastic slurry to create a composite rope, which will be used as 3D printing material. Roll the rope and create a cylindrical model for 3D printing in 3D modeling software. B. Printing the longitudinal winding layer: importing the round-head cylindrical model into a 3D printer system, setting the print head temperature of the 3D printer system, feeding the composite rope into the print head, and printing the longitudinal winding layer of the gas cylinder longitudinally until the printing is completed to form the main body of the gas cylinder; C. Filling the bottle with internal pressure: After the main body of the bottle is placed to cool, install an air injection valve at either end and fill the main body of the bottle with an internal pressure of 0.3-0.5MPa through the air injection valve; D. Hoop winding: After the internal pressure is filled, the internal pressure is maintained, and then multiple layers of the composite rope are circumferentially hot-melt wrapped around the entire longitudinal length of the outer surface of the main body of the bottle; the print head discharge temperature of the 3D printer system and the composite rope hot-melt wrapping temperature are set to the free flow temperature of the thermoplastic; E. Thermal expansion shaping: Heat the bottle body after the hoop hot melt wrapping to the softening temperature of the thermoplastic while maintaining the internal pressure, keep the constant temperature for 30 minutes, then cool it naturally to room temperature, and then release the pressure to complete the production of the bottle body.

2. A method for manufacturing a fully wrapped linerless gas cylinder according to claim 1, characterized in that: The high-strength and lightweight fiber rope is made of carbon fiber, glass fiber or bamboo fiber.