What are the common valve failures? There are two types of valve leakage, namely external leakage and internal leakage.

一、外漏常见于阀体、阀杆、填料函与阀体的连接部位。

1、 External leakage is common in the connecting parts of valve body, valve stem, stuffing box and valve body.

（1）阀体通常是铸造的，容易形成砂眼等铸造缺陷，阀体上的砂眼会导致介质的泄漏，这种泄漏一般都表现为渗漏，流量较小。

(1) The valve body is usually cast, which is easy to form sand holes and other casting defects. The sand holes on the valve body will lead to medium leakage. This leakage is generally manifested as leakage and small flow.

（2）阀门的阀杆由于设计和选材不当会引起阀杆在某个位置被卡死，使阀门无法关闭或关闭不严，造成介质泄漏。此种泄漏往往流量较大，对生产装置和周围的环境容易造成严重的危害。

(2) Improper design and material selection of the valve stem will cause the valve stem to be stuck at a certain position, so that the valve cannot be closed or not tightly closed, resulting in medium leakage. This kind of leakage often has a large flow, which is easy to cause serious harm to the production device and the surrounding environment.

（3）填料阀由填料函、填料、填料垫以及填料压紧机构等组成。填料函置于阀体或阀盖上，起容纳填料的作用。填料垫置于填料箱底部，起支撑填料的作用。填料分软质密封填料和成型填料两种。介质在密封填料处泄漏，原因为填料压盖松动、密封填料不严密、填料品种或质量不符合要求、填料老化或被阀杆磨损。

(3) The packing valve is composed of packing box, packing, packing pad and packing pressing mechanism. The stuffing box is placed on the valve body or bonnet to contain the packing. The packing pad is placed at the bottom of the stuffing box to support the packing. The packing is divided into soft sealing packing and molding packing. The medium leaks at the sealing packing because the packing gland is loose, the sealing packing is not tight, the packing variety or quality does not meet the requirements, the packing is aging or worn by the valve stem.

（4）阀体连接部位的密封系指阀体与阀盖之间的密封。一般情况下为法兰连接密封，当调节阀门公称直径较小时为螺纹连接密封。垫片的类型、材质或尺寸不符合要求、法兰密封面加工质量差、连接螺栓紧固不当、因管道配置不合理而在连接处产生过大附加载荷等原因，都能引起阀体连接部位泄漏。

(4) The sealing of the connecting part of the valve body refers to the sealing between the valve body and the bonnet. Generally, it is flange connection seal. When the nominal diameter of the regulating valve is small, it is threaded connection seal. The type, material or size of gasket do not meet the requirements, poor processing quality of flange sealing surface, improper fastening of connecting bolts, excessive additional load at the connection due to unreasonable pipeline configuration and other reasons can cause leakage at the connection part of valve body.

二、阀门关闭不严形成的泄漏为内漏，常发生在阀座密封面。

2、 The leakage caused by lax valve closing is internal leakage, which often occurs on the sealing surface of the valve seat.

（1）阀门的设计和制造工艺存在问题，造成阀门密封不严而导致介质的泄漏，多为渗漏或小流量连续排放。

(1) There are problems in the design and manufacturing process of the valve, resulting in the leakage of medium due to the lax sealing of the valve, mostly leakage or continuous discharge of small flow.

（2）阀板或密封面变形造成密封不严，从而引起介质的泄漏，一般成渗漏或小流量连续排放。

(2) The valve plate or sealing surface is deformed, resulting in loose sealing, resulting in medium leakage, which is generally leakage or small flow continuous discharge.

（3）在阀门的制造、运输、检验、安装和使用等过程中，损伤了阀门的密封面，使密封不严，导致阀门泄漏。这种泄漏也表现为小流量的渗漏。

(3) During the manufacturing, transportation, inspection, installation and use of the valve, the sealing surface of the valve is damaged, the sealing is not tight, and the valve leaks. This leakage is also manifested as small flow leakage.

（4）介质内含有固体杂质造成阀门关闭不严，从而引起介质泄漏。这种泄漏可能是小流量的渗漏也可能流量较大。

(4) The medium contains solid impurities, resulting in loose valve closure, resulting in medium leakage. This leakage may be small flow leakage or large flow.

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