螺纹/对焊闸阀

螺纹/对焊闸阀是阀体通道两端采用螺纹连接或对焊连接的闸阀。与法兰闸阀相比，这类阀门结构更加紧凑，重量更轻，主要用于小口径（通常为DN50以下）、高压力的管道系统。它们提供了一种长久性或半长久性的连接方案，密封性能很好，适用于不允许发生泄漏的苛刻工况。

螺纹/对焊闸阀主要特点

1. 紧凑轻便的结构：省去了法兰盘和螺栓连接结构，体积小，重量轻，特别适合空间受限的安装场合。

2. 很好的密封性：对焊连接提供了与管道浑然一体的强密封，从根本上消除了法兰连接面的潜在泄漏点，密封稳定性极高。螺纹连接则提供了良好的初始密封。

3. 螺纹/对焊闸阀适用于高压工况：对焊连接的结构强度高，能有效承受管道热应力和机械振动，是高压、高温或存在热循环工况下的理想选择。

4. 螺纹/对焊闸阀经济性：在同等压力等级下，对焊阀门通常比法兰阀门成本更低，且省去了法兰、垫片和螺栓的成本。

5. 多种连接组合：常见的组合有：入口和出口均为螺纹（Threaded x Threaded），入口和出口均为对焊（Butt Weld x Butt Weld），或一端螺纹一端对焊（Threaded x Butt Weld），提供了灵活的管道设计选择。

螺纹/对焊闸阀应用领域与区别

· 螺纹连接闸阀：

  · 优点：安装拆卸方便，可重复使用，无需焊接。

  · 缺点：耐振动性能较差，不适合频繁拆卸的高压工况。密封依赖螺纹密封剂或聚四氟乙烯生料带。

  · 应用：常用于仪表测压管线、取样阀、设备接口、低压小口径的水、油、气系统。

· 对焊连接闸阀：

  · 优点：连接强度好，密封性很好，耐疲劳和抗振动性能很好，使用寿命长。

  · 缺点：安装和拆卸需要焊接和切割作业，不可重复使用，对安装工艺要求高。

  ·螺纹/对焊闸阀应用：广泛应用于石油化工、电站、核工业等要求稳定性的高温、高压、危险介质（如易燃、易爆、有毒介质）的关键管路上。

螺纹/对焊闸阀选型注意事项

· 根据管道压力、温度、介质特性选择阀体材质（如A105, F304, F316）。

· 螺纹/对焊闸阀明确连接端标准：螺纹类型（如NPT, BSPT, BSPP）或对焊端坡口尺寸（与管道规格匹配）。

·螺纹/对焊闸阀考虑未来是否需要维护拆卸：需要经常拆卸的场合优先选择螺纹或法兰连接；追求长久性密封和稳定性则选择对焊。

Product Overview of Threaded / Butt Weld Gate Valve

I. Product Introduction

A Threaded/Butt Weld Gate Valve is a type of gate valve both ends of the valve body are designed for threaded butt weld connections.Compared to flanged gate valves, these valves feature a more compact structure lighter weight. They are primarily used in small-bore (typically below DN50) high-pressure piping systems. They provide a permanent semi-permanent connection solution with excellent sealing performance, making them suitable for demanding applications leakage is unacceptable.

Main Features

1. Compact Lightweight Design: The elimination of flanges bolts results in a smaller size reduced weight, making them ideal for installations space is constrained.

2. Excellent Sealing Integrity: Butt weld connections offer a strong, integral seal that becomes part of the pipeline, effectively eliminating potential leak paths associated with flange gaskets. Threaded connections provide good initial sealing.

3. Suitability for High-Pressure Service: The structural integrity of a butt weld connection allows it to withstand pipeline thermal stress mechanical vibration effectively, making it the preferred choice for high-pressure, high-temperature, thermal cycling applications.

4. Cost-Effectiveness: For the same pressure rating, butt weld valves are often more economical than flanged valves save on the cost of flanges, gaskets, bolts.

5. Variety of End Combinations: Common configurations include Threaded x Threaded (T/T), Butt Weld x Butt Weld (BW/BW), Threaded x Butt Weld (T/BW), offering flexibility in piping design.

Applications Distinctions

· Threaded Gate Valves:

  · Advantages: Easy installation removal, reusable, requires no welding.

  · Disadvantages: Less resistant to vibration; ideal for high-pressure services requiring frequent disassembly. Sealing relies on thread sealants PTFE tape.

  · Applications: Commonly used for instrument pressure lines, sample connections, equipment interfaces, low-pressure, small-bore systems for water, oil, gas.

· Butt Weld Gate Valves:

  · Advantages: Highest connection strength, superior sealing integrity, excellent fatigue vibration resistance, long service life.

  · Disadvantages: Installation removal require welding cutting operations, making them non-reusable demanding higher installation expertise.

  · Applications: Widely used in critical pipelines within petrochemical, power generation, nuclear industries absolute reliability is required for high-temperature, high-pressure, hazardous media (e.g., flammable, explosive, toxic).

Key Considerations for Selection

· body materials (e.g., A105, F304, F316) based on pipeline pressure, temperature, media characteristics.

· Specify end connection standards: Thread type (e.g., NPT, BSPT, BSPP) butt weld end bevel dimensions (to match the piping specification).

· Consider future maintenance needs: Threaded flanged connections are preferable for applications requiring frequent disassembly; Butt weld is chosen for permanent, leak-tight reliability.

螺纹/对焊闸阀核心术语中英对照：

· 螺纹/对焊闸阀：Threaded / Butt Weld Gate Valve

· 螺纹连接：Threaded Connection

· 对焊连接：Butt Weld Connection

· 紧凑型设计：Compact Design

· 小口径：Small Bore

· 承插焊：Socket Weld (另一种常见焊接方式)

· 坡口：Bevel

· NPT螺纹：National Pipe Taper Thread

· BSPT螺纹：British Standard Pipe Taper Thread

· 潜在泄漏点：Potential Leak Path

· 热循环：Thermal Cycling

· 机械振动：Mechanical Vibration