閥門連接方式的技術特性與選型指南閥門作為流體控制系統的核心組件，其連接方式直接影響管道系統的密封性、安裝效率及維護成本。不同工況對閥門連接形式提出差異化需求，合理選型需綜合考量介質特性、壓力等級、溫度范圍及操作便捷性。本文將系統解析主流閥門連接方式的技術特點，為工程實踐提供參考。

　　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、法蘭連接：標準化的可靠之選

　　1、 Flange connection: a standardized and reliable choice

　　法蘭連接通過螺栓將閥門法蘭與管道法蘭緊密貼合，中間夾持密封墊片，是目前應用最廣泛的連接形式。

　　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.

　　優勢：

　　Advantages:

　　密封性強：金屬墊片或柔性石墨墊片可耐受高壓、高溫及腐蝕性介質，適用于蒸汽、油氣等嚴苛工況。

　　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.

　　拆裝便捷：松開螺栓即可實現閥門在線檢修或更換，大幅縮短停機時間。某化工企業裂解裝置數據顯示，法蘭連接閥門維護效率較焊接連接提升。

　　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.

　　標準化程度高：遵循GB/T 9119、ANSI B16.5等標準，兼容性強，便于跨區域采購與備件管理。

　　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:

　　成本較高：法蘭、螺栓及墊片成本占閥門總價的，大口徑閥門成本優勢減弱。

　　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.

　　空間需求大：需預留法蘭操作空間，在緊湊布局場景中受限。

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

　　二、對夾連接：輕量化解決方案

　　2、 Clamp connection: lightweight solution

　　對夾式閥門通過雙頭螺栓直接夾持于兩管道法蘭之間，省略獨立法蘭結構。

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

　　優勢：

　　Advantages:

　　結構緊湊：軸向尺寸較法蘭連接縮短，適用于埋地管道或層高受限區域。某地鐵消防系統采用對夾蝶閥，節省安裝空間。

　　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.

　　重量輕：相同口徑下重量僅為法蘭連接的，降低支架負載。

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

　　成本優化：省略法蘭材料，綜合成本降低，在小口徑閥門中經濟性顯著。

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

　　局限：

　　Limitations:

　　密封面易損傷：安裝時需嚴格對中，偏斜可能導致墊片壓潰或泄漏。

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

　　承壓受限：通常適用于PN16以下低壓工況，高壓場景需增設加強筋。

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

　　三、螺紋連接：小口徑場景的主流選擇

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

　　螺紋連接通過內外螺紋旋合實現密封，常見于DN50以下閥門。

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

　　優勢：

　　Advantages:

　　安裝簡易：無需專用工具，手動即可完成組裝，適合家用給排水系統。

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

　　體積小巧：螺紋結構緊湊，適用于儀表管路或空間受限的實驗室環境。

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

　　自鎖性能：錐管螺紋（NPT）具備良好防松特性，減少振動工況泄漏風險。

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

　　局限：

　　Limitations:

　　承壓有限：通常適用于PN40以下低壓場景，高壓下螺紋易滑絲。

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

　　介質適應性差：不適用于含顆粒介質，螺紋間隙易堵塞導致拆卸困難。

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

　　四、焊接連接：高壓高溫工況的優選

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

　　閥門與管道通過焊接形成整體，分為對焊與承插焊兩種形式。

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

　　優勢：

　　Advantages:

　　密封性卓越：焊縫金屬融合，無泄漏路徑，適用于LNG、氫氣等高危介質。某煉化項目數據顯示，焊接連接閥門泄漏率僅為法蘭連接的。

　　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.

　　強度高：可承受高壓沖擊，在石油開采、火電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：焊縫內壁平整，減少流體阻力，適合大口徑長輸管線。

　　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:

　　維護困難：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.

　　熱影響風險：焊接高溫可能破壞閥門內部元件，需采取焊后熱處理。

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

　　隨著材料科學與加工技術進步，復合連接形式（如法蘭-焊接混合結構）正逐步涌現，為復雜工況提供更優解決方案。

　　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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