阀门连接方式的技术特性与选型指南阀门作为流体控制系统的核心组件，其连接方式直接影响管道系统的密封性、安装效率及维护成本。不同工况对阀门连接形式提出差异化需求，合理选型需综合考量介质特性、压力等级、温度范围及操作便捷性。本文将系统解析主流阀门连接方式的技术特点，为工程实践提供参考。

　　The technical characteristics and selection guidelines of valve connection methods. As the core component of fluid control systems, the connection method of valves directly affects the sealing, installation efficiency, and maintenance cost of pipeline systems. Different working conditions require differentiated valve connection forms, and reasonable selection should comprehensively consider the characteristics of the medium, pressure level, temperature range, and ease of operation. This article will systematically analyze the technical characteristics of mainstream valve connection methods, providing reference for engineering practice.

　　一、法兰连接：标准化的可靠之选

　　1、 Flange connection: a standardized and reliable choice

　　法兰连接通过螺栓将阀门法兰与管道法兰紧密贴合，中间夹持密封垫片，是目前应用最广泛的连接形式。

　　The flange connection tightly adheres the valve flange to the pipeline flange through bolts, with a sealing gasket clamped in between, which is currently the most widely used connection form.

　　优势：

　　Advantages:

　　密封性强：金属垫片或柔性石墨垫片可耐受高压、高温及腐蚀性介质，适用于蒸汽、油气等严苛工况。

　　Strong sealing: Metal gaskets or flexible graphite gaskets can withstand high pressure, high temperature, and corrosive media, suitable for harsh working conditions such as steam, oil, and gas.

　　拆装便捷：松开螺栓即可实现阀门在线检修或更换，大幅缩短停机时间。某化工企业裂解装置数据显示，法兰连接阀门维护效率较焊接连接提升。

　　Easy disassembly and assembly: Simply loosen the bolts to achieve online maintenance or replacement of the valve, greatly reducing downtime. The data of a cracking unit in a chemical enterprise shows that the maintenance efficiency of flange connected valves is higher than that of welded connections.

　　标准化程度高：遵循GB/T 9119、ANSI B16.5等标准，兼容性强，便于跨区域采购与备件管理。

　　High degree of standardization: Following standards such as GB/T 9119 and ANSI B16.5, it has strong compatibility and facilitates cross regional procurement and spare parts management.

　　局限：

　　Limitations:

　　成本较高：法兰、螺栓及垫片成本占阀门总价的，大口径阀门成本优势减弱。

　　High cost: The cost of flanges, bolts, and gaskets accounts for the total price of the valve, and the cost advantage of large-diameter valves is weakened.

　　空间需求大：需预留法兰操作空间，在紧凑布局场景中受限。

　　Large space requirement: flange operation space needs to be reserved, which is limited in compact layout scenarios.

　　二、对夹连接：轻量化解决方案

　　2、 Clamp connection: lightweight solution

　　对夹式阀门通过双头螺栓直接夹持于两管道法兰之间，省略独立法兰结构。

　　The clamp type valve is directly clamped between two pipeline flanges using double headed bolts, omitting the independent flange structure.

　　优势：

　　Advantages:

　　结构紧凑：轴向尺寸较法兰连接缩短，适用于埋地管道或层高受限区域。某地铁消防系统采用对夹蝶阀，节省安装空间。

　　Compact structure: The axial dimension is shortened compared to flange connections, making it suitable for buried pipelines or areas with limited floor height. The fire protection system of a certain subway adopts clamp butterfly valves to save installation space.

　　重量轻：相同口径下重量仅为法兰连接的，降低支架负载。

　　Lightweight: The weight of the same caliber is only for flange connections, reducing the load on the bracket.

　　成本优化：省略法兰材料，综合成本降低，在小口径阀门中经济性显著。

　　Cost optimization: Omitting flange materials, reducing overall costs, and achieving significant economic benefits in small-diameter valves.

　　局限：

　　Limitations:

　　密封面易损伤：安装时需严格对中，偏斜可能导致垫片压溃或泄漏。

　　The sealing surface is prone to damage: strict alignment is required during installation, and deviation may cause the gasket to crush or leak.

　　承压受限：通常适用于PN16以下低压工况，高压场景需增设加强筋。

　　Pressure limited: usually applicable to low-pressure conditions below PN16, and reinforcement bars need to be added in high-pressure scenarios.

　　三、螺纹连接：小口径场景的主流选择

　　3、 Threaded Connection: The Mainstream Choice for Small Diameter Scenarios

　　螺纹连接通过内外螺纹旋合实现密封，常见于DN50以下阀门。

　　Threaded connections achieve sealing by screwing internal and external threads, commonly found in valves below DN50.

　　优势：

　　Advantages:

　　安装简易：无需专用工具，手动即可完成组装，适合家用给排水系统。

　　Easy installation: No special tools required, manual assembly can be completed, suitable for household water supply and drainage systems.

　　体积小巧：螺纹结构紧凑，适用于仪表管路或空间受限的实验室环境。

　　Compact size: The threaded structure is compact and suitable for instrument pipelines or laboratory environments with limited space.

　　自锁性能：锥管螺纹（NPT）具备良好防松特性，减少振动工况泄漏风险。

　　Self locking performance: The taper pipe thread (NPT) has good anti loosening characteristics, reducing the risk of leakage under vibration conditions.

　　局限：

　　Limitations:

　　承压有限：通常适用于PN40以下低压场景，高压下螺纹易滑丝。

　　Limited pressure: usually suitable for low-pressure scenarios below PN40, where threads are prone to slipping under high pressure.

　　介质适应性差：不适用于含颗粒介质，螺纹间隙易堵塞导致拆卸困难。

　　Poor adaptability to media: Not suitable for media containing particles, thread gaps are prone to blockage, making disassembly difficult.

　　四、焊接连接：高压高温工况的优选

　　4、 Welding Connection: Optimal Selection for High Pressure and High Temperature Working Conditions

　　阀门与管道通过焊接形成整体，分为对焊与承插焊两种形式。

　　Valves and pipelines are formed as a whole through welding, which can be divided into two forms: butt welding and socket welding.

　　优势：

　　Advantages:

　　密封性卓越：焊缝金属融合，无泄漏路径，适用于LNG、氢气等高危介质。某炼化项目数据显示，焊接连接阀门泄漏率仅为法兰连接的。

　　Excellent sealing performance: weld metal fusion, no leakage path, suitable for high-risk media such as LNG and hydrogen. Data from a certain refining project shows that the leakage rate of welded valves is only higher than that of flange connections.

　　强度高：可承受高压冲击，在石油开采、火电主蒸汽管道中不可替代。

　　High strength: capable of withstanding high-pressure impacts, irreplaceable in oil extraction and thermal power main steam pipelines.

　　流阻小：焊缝内壁平整，减少流体阻力，适合大口径长输管线。

　　Low flow resistance: The inner wall of the weld seam is flat, reducing fluid resistance and suitable for large-diameter long-distance pipelines.

　　局限：

　　Limitations:

　　维护困难：焊接后需切割拆除，增加全生命周期成本。

　　Maintenance difficulty: Cutting and dismantling after welding increases the overall lifecycle cost.

　　热影响风险：焊接高温可能破坏阀门内部元件，需采取焊后热处理。

　　Thermal impact risk: Welding at high temperatures may damage the internal components of the valve, and post weld heat treatment is required.

　　随着材料科学与加工技术进步，复合连接形式（如法兰-焊接混合结构）正逐步涌现，为复杂工况提供更优解决方案。

　　With the advancement of materials science and processing technology, composite connection forms (such as flange welding hybrid structures) are gradually emerging, providing better solutions for complex working conditions.

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