Weldless high-pressure container

Abstract

The utility model discloses a weldless high-pressure container, which comprises an integrally formed cylinder body, the connecting assemblies are arranged at the two ends of the barrel and used for achieving non-welding connection between the barrel and the end structure; the self-tightening sealing structure is arranged on a contact interface of the cylinder body and the end part structure and is used for self-adaptively enhancing the pressure intensity of a sealing contact surface under the action of medium pressure; the connecting assembly and the self-tightening type sealing structure act synergistically so as to eliminate residual stress of a welding seam and reduce dependence of sealing on pre-tightening force. The connecting assembly and the self-tightening type sealing structure act synergistically so as to eliminate residual stress of a welding seam and reduce dependence of sealing on pre-tightening force.

Description

Technical Field

[0001] This utility model relates to the field of pressure vessel design and manufacturing technology, specifically to a seamless high-pressure vessel. Background Technology

[0002] High-pressure vessels, as core components of pressure-bearing equipment, are widely used in petrochemical, hydrogen energy storage and transportation, aerospace, and other fields. Traditional high-pressure vessels are generally manufactured using welding processes, with the cylinder and head connected by welds, which has the following inherent defects:

[0003] 1. Welding defects and residual stress: Slag inclusions, porosity, lack of fusion, and microcracks are easily generated during welding (especially in the welding of thick plates of high-strength steel), leading to stress concentration and reduced fatigue life (the slope of the S / N curve increases by about 20%-30%). Although post-weld heat treatment can partially eliminate residual stress, it cannot completely avoid the grain coarsening problem in the heat-affected zone (HAZ).

[0004] 2. Limited material selection: Welding-sensitive materials cannot be used: The welding process has strict requirements on the weldability of materials. 17-4PH precipitation-hardening stainless steel, which has excellent resistance to hydrogen embrittlement, is prone to precipitating δ-ferrite (volume fraction ≥8%) in the HAZ during welding, resulting in a 50%-70% decrease in impact toughness. A286 iron-nickel-based superalloy, due to its high Al / Ti content (Al 0.35%, Ti 2.25%), is prone to forming brittle Ti(C,N) phases during welding, and its fracture toughness after welding is only 30%-40% of that in the forged state.

[0005] 3. Deterioration of high-strength material properties: For example, the strength of AA 7075 aluminum alloy welded joints is only 50%-60% of that of the base material, and its performance cannot be restored by aging treatment after welding, which greatly limits its application in high-pressure vessels.

[0006] 4. Insufficient sealing reliability: Existing detachable flange connections mostly use flat seals (RF face) or octagonal gasket seals, relying on high bolt preload (preload coefficient typically ≥2.5) to maintain the sealing pressure. Under pressure pulsation conditions (such as hydrogen compressor buffer tanks), the sealing surface is prone to fretting wear, leading to an exponential increase in leakage rate with the number of cycles (10). 6 The leakage rate increases by 3-5 times after each cycle.

[0007] 5. Vibration fatigue and hydrogen embrittlement risk: In high-pressure hydrogen environments, the HAZ region of conventional welded vessels is prone to hydrogen-induced cracking (HIC), with crack propagation rates 2-3 orders of magnitude higher than the base material. Furthermore, vibration accelerations at flange connections caused by pipeline pressure pulsations can reach 50-100 m / s². 2 This significantly accelerates bolt loosening and seal failure. Summary of the Invention

[0008] The utility model discloses a purpose at providing a kind of weldless high-pressure vessel, to solve the technical problem existing in background art.

[0009] To achieve the above object, the utility model adopts the following technical solutions:

[0010] A weldless high-pressure vessel, characterized in that, comprising:

[0011] The barrel body is integrally formed.

[0012] The connecting assembly is arranged at both ends of the barrel body, and is used to realize the non-welded connection between the barrel body and the end structure.

[0013] The self-tightening sealing structure is arranged at the contact interface between the barrel body and the end structure, and is used to adaptively enhance the pressure of the sealing contact surface under the action of the medium pressure.

[0014] The connecting assembly and the self-tightening sealing structure cooperate to eliminate the weld residual stress and reduce the dependence of the sealing on the pre-tightening force.

[0015] In some embodiments, the connecting assembly includes a flange and a plug, the flange is connected to the end of the barrel body through a high-strength bolt set, and the plug is embedded in the inner cavity of the end of the barrel body and is integrated with the flange.

[0016] The self-tightening sealing structure is a self-tightening radial sealing structure, which is arranged between the outer wall of the plug and the inner wall of the barrel body, and the sealing direction is perpendicular to the barrel axis.

[0017] In some embodiments, the self-tightening radial sealing structure includes a metal sealing ring or an elastomer sealing structure.

[0018] The metal sealing ring is a self-tightening metal ring with a C-shaped or U-shaped cross section, and the elastomer sealing structure is an O-ring, a Gleece ring or a PTFE seal.

[0019] The material of the sealing structure is selected according to the working condition parameters, the metal sealing ring is made of austenitic stainless steel, Inconel alloy or titanium alloy, and the elastomer sealing structure is made of fluororubber, perfluoroether rubber or hydrogenated nitrile rubber.

[0020] In some embodiments, the surface roughness Ra of the sealing surface of the barrel body and the plug is ≤0.4 μm.

[0021] The barrel body and the plug are processed from a forged piece, and the grain size grade after forging is not less than ASTM 8 grade.

[0022] In some embodiments, the material of the barrel body and the plug is selected according to the requirement of hydrogen environment, including hydrogen embrittlement sensitive material 17-4PH, A286 high-temperature alloy or Inconel718.

[0023] The forging process of the material matches the high-temperature strength and corrosion resistance thereof.

[0024] In some embodiments, the pre-tightening coefficient of the high-strength bolt group is reduced by more than 30% compared with a traditional flat sealing structure.

[0025] The outer diameter of the flange and the bolt center distance are designed to be lightweight based on the target of reducing the flange shear stress and bending moment.

[0026] In some embodiments, the pressure limit of the self-tightening sealing structure is ≥350MPa, and the leakage rate is ≤1×10 - 6 mbar·L / s.

[0027] The sealing structure maintains the contact specific pressure through elastic deformation under pressure fluctuation conditions, and the anti-fretting wear performance is better than that of a traditional flat seal.

[0028] In some embodiments, the container is suitable for a hydrogen environment with a design pressure ≥35MPa, and the fatigue life is ≥10 7 cycles.

[0029] The cylinder body is free of welds and heat-affected zones, and the crack propagation rate is ≤10 -6 mm / s.

[0030] The beneficial effects that can be brought by the non-welded high-pressure container disclosed in the present application include but are not limited to:

[0031] Non-welded integrity: completely eliminate weld defects and residual stress, base crack propagation rate ≤10 -6 mm / s, fatigue life ≥10 7 cycles.

[0032] High-pressure sealing reliability: self-tightening sealing leakage rate ≤1×10 -6 mbar·L / s, pressure limit ≥350MPa, suitable for pressure pulsation conditions.

[0033] Hydrogen embrittlement resistance and lightweight: compatible with welding sensitive materials, suitable for hydrogen environment (design pressure ≥35MPa), structure weight reduced by 20%-30%. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The structure diagram of the non-welded high-pressure container is provided.

[0035] Explanation of reference numerals in the drawing: 1-cylinder body, 2-high-strength bolt group, 3-flange, 4-plug, 5-self-tightening radial sealing structure. DETAILED DESCRIPTION

[0036] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0037] Conversely, this application covers any substitutions, modifications, equivalent methods, and schemes made within the spirit and scope of this application as defined in the claims. Furthermore, to provide the public with a better understanding of this application, certain specific details are described in detail below. However, this application can be fully understood by those skilled in the art even without these detailed descriptions.

[0038] like Figure 1 As shown, a seamless high-pressure vessel is characterized by comprising:

[0039] Seamless cylinder 1: Cylinder 1 is integrally forged from high-strength alloy, without welds or heat-affected zones. After forging, the grain size is ≥ASTM grade 8, and the surface roughness Ra≤0.4μm.

[0040] The connecting components disposed at both ends of the cylinder 1 are used to realize the non-welded connection between the cylinder 1 and the end structure;

[0041] The connecting assembly includes a flange 3 and a plug 4. The flange 3 is connected to the end of the cylinder 1 by a high-strength bolt group 2. The plug 4 is embedded in the inner cavity of the end of the cylinder 1 and is integrally formed with the flange 3.

[0042] A self-tightening sealing structure is provided at the contact interface between the cylinder 1 and the end structure to adaptively enhance the pressure of the sealing contact surface under the action of medium pressure; the self-tightening sealing structure is a self-tightening radial sealing structure 5, which is provided between the outer wall of the plug 4 and the inner wall of the cylinder 1, and the sealing direction is perpendicular to the axis of the cylinder 1.

[0043] The connecting component works in conjunction with the self-tightening sealing structure to eliminate residual stress in the weld and reduce the seal's dependence on preload.

[0044] In some embodiments, the self-tightening radial sealing structure 5 includes a metal sealing ring or an elastomer sealing structure; the metal sealing ring is a self-tightening metal ring with a C-shaped or U-shaped cross section, and the elastomer sealing structure is an O-ring, a Glyd ring, or a plug seal;

[0045] The material of the sealing structure is selected according to the working parameters. The metal sealing ring is made of austenitic stainless steel, Inconel nickel alloy or titanium alloy, and the elastomer sealing structure is made of fluororubber, perfluoroether rubber or hydrogenated nitrile rubber.

[0046] In some embodiments, the sealing surface roughness Ra of the cylinder 1 and the plug 4 is less than or equal to 0.4 microns; the cylinder 1 and the plug 4 are processed from a forged piece, and the grain size grade after forging is not less than ASTM 8 level.

[0047] The material of the cylinder 1 and the plug 4 is selected according to the requirements of the hydrogen environment, including hydrogen embrittlement sensitive materials 17-4PH, A286 high-temperature alloy or Inconel718; the forging process of the material is matched with the high-temperature strength and corrosion resistance.

[0048] In some embodiments, the pre-tightening coefficient of the high-strength bolt set 2 is reduced by more than 30% compared with the traditional flat sealing structure; the outer diameter of the flange 3 and the bolt center distance are designed to be lightweight based on the target of reducing the flange shear stress and bending moment.

[0049] The pressure limit of the self-tightening sealing structure is greater than or equal to 350 MPa, and the leakage rate is less than or equal to 1x10 -6 mbar·L / s; the sealing structure maintains the contact specific pressure through elastic deformation under pressure fluctuation conditions, and the anti-fretting wear performance is better than that of the traditional flat sealing. The container is suitable for a hydrogen environment with a design pressure greater than or equal to 35 MPa, and the fatigue life is greater than or equal to 10 7 times of cycles; the cylinder 1 has no weld and heat-affected zone, and the crack propagation rate is less than or equal to 10 -6 mm / s.

[0050] The present application completely eliminates the weld defects and residual stress of the traditional welded container through the weldless cylinder 1 + self-tightening sealing + structural mechanics collaborative design, significantly reduces the bolt pre-tightening force requirement (reduction of 60%-70%) and the flange stress concentration; the adaptability selection of the hydrogen embrittlement resistant material and the detachable structure consider the high-pressure sealing reliability and the long-period maintenance convenience. The lightweight, anti-fatigue and extreme condition adaptability (hydrogen, supercritical fluid) provide an innovative solution for hydrogen energy storage and transportation, aerospace and other fields.

[0051] The present application takes the weldless integrated design as the core, breaks through the technical shackles of the traditional high-pressure container relying on welding and high pre-tightening force and high design redundancy, realizes the collaborative leap of sealing reliability, fatigue life and lightweight performance through multi-dimensional innovation of structure-material-process. The technical concept not only sets a new benchmark for the reliability of high-pressure equipment, but also provides key hardware support for strategic fields such as clean energy and deep space exploration, and promotes the high-quality development of the industry towards high efficiency, safety and sustainability with new productivity.

[0052] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A seamless high-pressure vessel, characterized in that, include: One-piece molded cylindrical body (1); The connecting components disposed at both ends of the cylinder (1) are used to realize the non-welded connection between the cylinder and the end structure; A self-tightening sealing structure is provided at the contact interface between the cylinder (1) and the end structure to adaptively enhance the pressure of the sealing contact surface under the action of medium pressure. The connecting component works in conjunction with the self-tightening sealing structure to eliminate residual stress in the weld and reduce the seal's dependence on preload.

2. The seamless high-pressure vessel according to claim 1, characterized in that: The connecting assembly includes a flange (3) and a plug (4). The flange (3) is connected to the end of the cylinder (1) by a high-strength bolt group (2). The plug (4) is embedded in the inner cavity of the end of the cylinder (1) and is integrally formed with the flange (3). The self-tightening sealing structure is a self-tightening radial sealing structure (5), which is located between the outer wall of the plug (4) and the inner wall of the cylinder (1), with the sealing direction perpendicular to the cylinder axis.

3. The seamless high-pressure vessel according to claim 2, characterized in that: The self-tightening radial sealing structure (5) includes a metal sealing ring or an elastomer sealing structure; The metal sealing ring is a self-tightening metal ring with a C-shaped or U-shaped cross section, and the elastomeric sealing structure is an O-ring, a Glyd ring, or a pan-seal.

4. The seamless high-pressure vessel according to claim 2, characterized in that: The surface roughness Ra of the sealing surfaces of the cylinder (1) and the plug (4) is ≤0.4μm; The cylinder (1) and the plug (4) are made of forgings, and the grain size grade after forging is not lower than ASTM grade 8.

5. The seamless high-pressure vessel according to claim 2, characterized in that: The preload coefficient of the high-strength bolt group (2) is reduced by more than 30% compared with the traditional planar sealing structure.

6. The seamless high-pressure vessel according to claim 1, characterized in that: The pressure resistance of the self-tightening sealing structure is ≥350MPa, and the leakage rate is ≤1×10⁻⁶. -6 mbar·L / s.

7. The seamless high-pressure vessel according to claim 1, characterized in that: The cylinder (1) has no weld seams or heat-affected zone, and the crack propagation rate is ≤10. -6 mm / s.

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