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

一、外漏常見(jiàn)于閥體、閥桿、填料函與閥體的連接部位。

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

（1）閥體通常是鑄造的，容易形成砂眼等鑄造缺陷，閥體上的砂眼會(huì)導(dǎo)致介質(zhì)的泄漏，這種泄漏一般都表現(xiàn)為滲漏，流量較小。

(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）閥門(mén)的閥桿由于設(shè)計(jì)和選材不當(dāng)會(huì)引起閥桿在某個(gè)位置被卡死，使閥門(mén)無(wú)法關(guān)閉或關(guān)閉不嚴(yán)，造成介質(zhì)泄漏。此種泄漏往往流量較大，對(duì)生產(chǎn)裝置和周?chē)沫h(huán)境容易造成嚴(yán)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）填料閥由填料函、填料、填料墊以及填料壓緊機(jī)構(gòu)等組成。填料函置于閥體或閥蓋上，起容納填料的作用。填料墊置于填料箱底部，起支撐填料的作用。填料分軟質(zhì)密封填料和成型填料兩種。介質(zhì)在密封填料處泄漏，原因?yàn)樘盍蠅荷w松動(dòng)、密封填料不嚴(yán)密、填料品種或質(zhì)量不符合要求、填料老化或被閥桿磨損。

(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）閥體連接部位的密封系指閥體與閥蓋之間的密封。一般情況下為法蘭連接密封，當(dāng)調(diào)節(jié)閥門(mén)公稱(chēng)直徑較小時(shí)為螺紋連接密封。墊片的類(lèi)型、材質(zhì)或尺寸不符合要求、法蘭密封面加工質(zhì)量差、連接螺栓緊固不當(dāng)、因管道配置不合理而在連接處產(chǎn)生過(guò)大附加載荷等原因，都能引起閥體連接部位泄漏。

(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、閥門(mén)關(guān)閉不嚴(yán)形成的泄漏為內(nèi)漏，常發(fā)生在閥座密封面。

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

（1）閥門(mén)的設(shè)計(jì)和制造工藝存在問(wèn)題，造成閥門(mén)密封不嚴(yán)而導(dǎo)致介質(zhì)的泄漏，多為滲漏或小流量連續(xù)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）閥板或密封面變形造成密封不嚴(yán)，從而引起介質(zhì)的泄漏，一般成滲漏或小流量連續(xù)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）在閥門(mén)的制造、運(yùn)輸、檢驗(yàn)、安裝和使用等過(guò)程中，損傷了閥門(mén)的密封面，使密封不嚴(yán)，導(dǎo)致閥門(mén)泄漏。這種泄漏也表現(xiàn)為小流量的滲漏。

(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）介質(zhì)內(nèi)含有固體雜質(zhì)造成閥門(mén)關(guān)閉不嚴(yán)，從而引起介質(zhì)泄漏。這種泄漏可能是小流量的滲漏也可能流量較大。

(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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