阀门因其种类多、数量大，是工业系统装置中主要泄漏源之一，阀门泄露不仅会造成资源的浪费，还可能对生活和生产带来危险。在化工行业中，有毒、有害、易燃、易爆及腐蚀性介质的泄露可能严重威胁人身、财产和环境污染，因此对阀门的密封性要求关重要。

　　Valves, due to their wide variety and large quantity, are one of the main sources of leakage in industrial system devices. Valve leakage not only causes waste of resources, but may also pose a danger to life and production. In the chemical industry, the leakage of toxic, harmful, flammable, explosive, and corrosive media may seriously threaten personal safety, property safety, and environmental pollution. Therefore, the sealing requirements for valves are crucial.

　　阀门密封性能是指阀门各密封部位阻止介质泄漏的能力。其位置主要可以分为三个关键部分：

　　Valve sealing performance refers to the ability of each sealing part of the valve to prevent medium leakage. Its location can be mainly divided into three key parts:

　　处：启闭件与阀座两密封面间的接触处。这是阀门密封的主要位置，也是防止介质泄漏的道防线。启闭件（如阀门门板）与阀座之间的接触面，通过精确的加工和配合，形成紧密的密封结构。这一位置的泄漏被称为“内漏”，它将影响阀门截断介质的能力。

　　The first point is the contact area between the opening and closing components and the two sealing surfaces of the valve seat. This is the main location for valve sealing and also the first line of defense against medium leakage. The contact surface between the opening and closing components (such as valve door panels) and the valve seat forms a tight sealing structure through precise machining and fitting. The leakage at this location is called "internal leakage", which will affect the valve's ability to cut off the medium.

　　第二处：填料与阀杆和填料函的配合处。这是阀门的另一个重要密封位置，主要用于防止介质通过阀杆和填料函之间的间隙泄漏。填料（如石墨、聚四氟乙烯等）被填充在阀杆周围，通过压紧和变形，形成与阀杆和填料函之间的密封。这里的泄漏通常被称为“外漏”，即介质从阀内泄漏到阀外。

　　The second part: the fitting between the packing and the valve stem and packing box. This is another important sealing position of the valve, mainly used to prevent medium leakage through the gap between the valve stem and the packing box. Fillers (such as graphite, polytetrafluoroethylene, etc.) are filled around the valve stem, and through compression and deformation, a seal is formed between the valve stem and the packing box. The leakage here is usually referred to as "external leakage", which means that the medium leaks from inside the valve to outside.

　　第三处：阀体与阀盖的连接处。这是阀门的第三个密封位置，用于确保阀体和阀盖之间的连接处不会发生泄漏。通常通过法兰连接、螺纹连接或焊接等方式实现阀体与阀盖的紧密连接。在这些连接处，可能会使用密封垫片、密封胶等辅助材料来增强密封效果。

　　The third point: the connection between the valve body and the valve cover. This is the third sealing position of the valve, used to ensure that there is no leakage at the connection between the valve body and the valve cover. The tight connection between the valve body and the valve cover is usually achieved through flange connection, threaded connection, or welding. At these connections, auxiliary materials such as sealing gaskets and sealants may be used to enhance the sealing effect.

　　阀门的密封形式，主要可以分为以下四类：

　　The sealing forms of valves can be mainly divided into the following four categories:

　　一、焊接密封

　　1、 Welding seal

　　焊接密封是利用焊接技术将阀门与管道连接起来，从而实现密封的目的。这种密封形式适用于小口径、低压力的管道系统，常见的焊缝形式有对接焊接和螺纹焊接两种。对接焊接通常应用于高压力或直径较大的管道上，而螺纹焊接通常应用于低压力或直径较小的管道上。

　　Welding sealing is the use of welding technology to connect valves and pipelines, thereby achieving the purpose of sealing. This sealing form is suitable for small-diameter, low-pressure pipeline systems, and common weld forms include butt welding and threaded welding. Docking welding is usually applied to high-pressure or large-diameter pipelines, while threaded welding is usually applied to low-pressure or small-diameter pipelines.

　　二、压力密封压力密封是利用压力将阀门与管道之间的间隙密封起来，通过密封面和密封面之间的相互挤压以达到完全密封的效果。常见的压力密封形式包括平面密封、锥面密封、球面密封、全金属密封等。

　　2、 Pressure sealing is the use of pressure to seal the gap between a valve and a pipeline, achieving complete sealing through mutual compression between the sealing surfaces. Common forms of pressure seals include flat seals, conical seals, spherical seals, all metal seals, etc.

　　三、摩擦密封摩擦密封利用材料之间的摩擦力来阻止流体泄漏，是一种重要的密封形式之一。根据材料磨合方式的不同，摩擦密封又可以分为动密封和静密封两种。常见的摩擦密封形式包括填料密封、弹性密封、气体密封、真空密封等。

　　3、 Friction sealing utilizes the frictional force between materials to prevent fluid leakage and is one of the important forms of sealing. According to the different ways of material running in, friction seals can be divided into two types: dynamic seals and static seals. Common forms of friction seals include packing seals, elastic seals, gas seals, vacuum seals, etc.

　　四、其他密封形式此外，还存在一些其他的密封形式，如边界密封、界面密封、密码锁紧等。边界密封是指在管道系统内外设置一个或多个密封环，将管道内的流体隔开来实现密封的目的。界面密封则是利用不

　　4、 In addition to other sealing forms, there are also some other sealing forms, such as boundary sealing, interface sealing, password locking, etc. Boundary sealing refers to setting one or more sealing rings inside and outside the pipeline system to isolate the fluid inside the pipeline and achieve the purpose of sealing. Interface sealing is not utilized

　　同介质之间的表面张力使得流体不发生渗透现象实现低压力的密封。密码锁紧则是通过将密封界面上的两个零部件咬合在一起，达到紧密拼合的效果。

　　The surface tension between the same medium prevents fluid infiltration and achieves low-pressure sealing. Password locking is achieved by interlocking two components on the sealed interface together to achieve a tight fitting effect.

　　除此之外，我们通常也会在说法上进行区分，如软密封与硬密封，动密封与静密封。

　　In addition, we usually make distinctions in terms of terminology, such as soft seals and hard seals, dynamic seals and static seals.

　　硬密封:密封副的两侧均是金属材料或较硬的其它材料的被称为“硬密封”。这种密封的密封性能较差，但耐高温，抗磨损，机械性能好。如:钢+钢；钢+铜；钢+石墨；钢+合金钢。软密封 :密封副的两侧一侧是金属材料，另一侧是有弹性的非金属材料的被称为"软密封”，这种密封的密封性能较好，但不耐高温，易磨损，机械性较差。如 : 钢+橡胶；钢+四氟聚乙烯等。

　　Hard seal: A seal where both sides of the sealing pair are made of metal or other harder materials is called a "hard seal". This type of seal has poor sealing performance, but it is heat-resistant, wear-resistant, and has good mechanical properties. For example: steel+steel; Steel+copper; Steel+graphite; Steel+alloy steel. Soft seal: A sealing pair with metal material on one side and elastic non-metallic material on the other side is called a "soft seal". This type of seal has good sealing performance, but is not resistant to high temperatures, easy to wear, and has poor mechanical properties. Examples include steel+rubber, steel+PTFE, etc.

　　静密封也称固定密封，它是指被密封的组件间无相对运动的情况，通常静密封是靠密封垫片来实现的。动密封也称运动密封，它是指工作状态下被密封组件同存在着相对运动的情况。其密封方法主要是采用填料函。填料函形式包括压盖式和压紧螺母式，前者用得多，后者压紧力受限制，只使用于小阀门。

　　Static sealing, also known as fixed sealing, refers to the situation where there is no relative motion between the sealed components. Typically, static sealing is achieved through the use of sealing gaskets. Dynamic seal, also known as motion seal, refers to the situation where the sealed components are in relative motion during operation. The main sealing method is to use a stuffing box. The forms of stuffing boxes include gland type and compression nut type, with the former being the most commonly used and the latter being limited in compression force and only used for small valves.

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