1、閥體材料選用

　　1. Valve body material selection

　　對于鋼和鎳合金閥體和閥蓋材料的選擇在ASMEB16.34表1中已經(jīng)列出。這個表被分為三組：第1組是黑色金屬材料;第2組是奧氏體不銹鋼材料;第3組是與特殊的壓力-溫度等級表相關(guān)的鎳合金材料。在ASMEB16.1(鑄鐵)、ASMEB16.24(銅合金)、ASMEB16.42(球墨鑄鐵)中含有其他材料。

　　The selection of steel and nickel alloy valve body and cover materials is listed in Table 1 of ASMEB16.34. This table is divided into three groups: Group 1 is made of black metal materials; The second group is austenitic stainless steel materials; The third group is nickel alloy materials related to special pressure temperature rating tables. Other materials are present in ASMEB16.1 (cast iron), ASMEB16.24 (copper alloy), and ASMEB16.42 (ductile iron).

　　對于表中涉及溫度和熱處理范圍的注釋，需要給予特別關(guān)注。通過查閱這些溫度-壓力表，壓力-溫度額定值為選擇合理的滿足機械強度需求提供了依據(jù)。此外材料對許多存在于過程流體流動工況中材料性能下降機理，也應(yīng)該給予考慮，例如受到腐蝕、應(yīng)力開裂、低溫和高溫、含氫工況影響等。

　　Special attention should be paid to the annotations in the table regarding temperature and heat treatment range. By consulting these temperature pressure gauges, the pressure temperature rating provides a basis for selecting a reasonable one that meets the mechanical strength requirements. In addition, the mechanism of material performance degradation in many process fluid flow conditions should also be considered, such as corrosion, stress cracking, low and high temperature, and hydrogen containing conditions.

　　2、閥門內(nèi)件選用

　　2. Selection of valve internals

　　①通則 閥門內(nèi)件材料的選用不只是閥座密封面材料，在API600和API602包含的內(nèi)件表中對其有明確定義。通常對于所有類型的閥門其內(nèi)件包括所有與過程流體接觸的部件。如果沒有定義特殊的要求，那么API標準要求內(nèi)件材料的耐蝕性必須至少與閥體材料的耐蝕性相同。

　?、?The selection of valve internal material is not only limited to the sealing surface material of the valve seat, but is clearly defined in the internal material tables included in API600 and API602. Typically, for all types of valves, the internal components include all parts that come into contact with the process fluid. If no special requirements are defined, the API standard requires that the corrosion resistance of the internal material must be at least the same as that of the valve body material.

　?、陂l閥 對于閘閥，其內(nèi)件為關(guān)閉件和閥座密封面以及閥桿和上密封座。正如API標準中所指出的，一個避免閥座磨損的關(guān)鍵因素是為與其相配合的一對密封面提供一個不同的硬度，除非兩個密封面都是硬面。在參考標準中提供了內(nèi)件表。某些合理內(nèi)件是在一個或兩個表面進行耐磨堆焊，以更好地確保密封面長期具有耐磨損性能、耐蝕性能和耐磨性能。

　?、?For gate valves, the internal components include the closing element, valve seat sealing surface, valve stem, and upper sealing seat. As stated in the API standard, a key factor in avoiding valve seat wear is to provide a different hardness for the pair of sealing surfaces that match it, unless both sealing surfaces are hard surfaces. An internal component table is provided in the reference standard. Some reasonable internal components are subjected to wear-resistant welding on one or two surfaces to better ensure that the sealing surface has long-term wear resistance, corrosion resistance, and wear resistance.

　?、燮渌y門內(nèi)件 對于止回閥，其內(nèi)件被定義為關(guān)閉件和閥座密封面。在參考標準中提供了內(nèi)件表。某些合理的內(nèi)件是在一個或兩個表面進行耐磨堆焊，從而更好地確保閥座在長期磨損、腐蝕和磨蝕性工況使用中不會失效。

　?、?For check valves, the internal components of other valves are defined as the closing element and the sealing surface of the valve seat. An internal component table is provided in the reference standard. Some reasonable internal components are wear-resistant welded on one or two surfaces to better ensure that the valve seat will not fail in long-term wear, corrosion, and abrasive working conditions.

　　對于球閥，其關(guān)閉件被定義為閥門的內(nèi)部金屬件，例如球體、閥桿和金屬閥座或閥座支撐圈。這些件都可以具有與殼體相同的名義化學(xué)成分，以及具有與殼體材料相似的力學(xué)性能和耐蝕性能。

　　For ball valves, their closing components are defined as the internal metal parts of the valve, such as the ball, stem, and metal valve seat or seat support ring. These components can have the same nominal chemical composition as the shell, as well as mechanical and corrosion resistance properties similar to the shell material.

　　對于蝶閥，所有與過程流體接觸的材料都應(yīng)遵循制造商的標準，除另有規(guī)定外。蝶閥內(nèi)件被定義為閥體閥座密封面、蝶板、蝶板與軸連接件(例如鍵、銷、螺釘?shù)?和全部與過程流體接觸的內(nèi)部緊固件。軸和軸套的材料與內(nèi)件材料的腐蝕性能相似。

　　For butterfly valves, all materials in contact with the process fluid should comply with the manufacturer's standards, unless otherwise specified. Butterfly valve internals are defined as the valve body seat sealing surface, butterfly plate, butterfly plate and shaft connecting components (such as keys, pins, screws, etc.), and all internal fasteners in contact with the process fluid. The corrosion resistance of the materials of the shaft and sleeve is similar to that of the internal components.

　　對于旋塞閥，要求旋塞和閥桿材料的耐蝕性至少與閥體材料相同。

　　For plug valves, it is required that the corrosion resistance of the plug and stem materials be at least the same as that of the valve body material.

　　對于截止閥，其內(nèi)件見API602中定義。3、閥座密封面——軟閥座　　球閥和蝶閥經(jīng)常使用帶有彈性的、非金屬的閥座來提供密封。API608和API609中包含帶有壓力-溫度額定值規(guī)定的PTFE和增強型PTFE材料。其他軟閥座材料的壓力-溫度額定值，經(jīng)購買者和制造商商定。PTFE閥座的使用溫度范圍往往是177～225℃(350～400℉)。對于一些用于液體工況中的軟閥座球閥，應(yīng)該考慮中腔泄壓要求。4、閥桿密封——逸散性排放

　　For globe valves, their internal components are defined in API602. 3. Seat sealing surface - Soft seat ball valves and butterfly valves often use elastic, non-metallic seats to provide sealing. API608 and API609 contain PTFE and reinforced PTFE materials with pressure temperature ratings specified. The pressure temperature ratings of other soft seat materials shall be agreed upon by the purchaser and manufacturer. The operating temperature range of PTFE valve seats is often 177-225 ℃ (350-400 ℉). For some soft seat ball valves used in liquid working conditions, the requirement for pressure relief in the middle chamber should be considered. 4. Valve stem seal - fugitive emissions

　　通常用于工藝管道中的閥桿填料為一種柔性石墨。新閥門填料典型設(shè)計方法是：放置幾個壓制成形的幾道填料環(huán)，填料環(huán)上面放置一個編織材料環(huán)以及在堆疊填料的底部放置一個編織材料環(huán)。這種編織材料“擦拭環(huán)”有助于防止壓制填料環(huán)被擠出填料函。與先前使用的石棉材料相比，目前閥門填料技術(shù)有效地阻止了輕烴泄漏(逸散性排放)。影響柔性石墨填料材料性能的關(guān)鍵因素有：碳的百分含量、填料密度和耐蝕/氧化劑。為提高閥桿填料性能，MSS SP-120中對用于升降閥桿閥門的柔性石墨填料系統(tǒng)進行了很好的討論。API622的填料應(yīng)予以考慮。

　　The valve stem packing commonly used in process pipelines is a type of flexible graphite. The typical design method for new valve packing is to place several compressed packing rings, place a woven material ring on top of the packing rings, and place a woven material ring at the bottom of the stacked packing. This woven material 'wiping ring' helps prevent the compressed packing ring from being squeezed out of the packing box. Compared with the previously used asbestos materials, the current valve packing technology effectively prevents light hydrocarbon leakage (fugitive emissions). The key factors affecting the performance of flexible graphite filler materials include the percentage of carbon content, filler density, and corrosion/oxidation agents. To improve the performance of valve stem packing, MSS SP-120 provides a good discussion on the flexible graphite packing system used for lifting valve stem valves. The packing of API622 should be considered.

　　雖然石墨材料在溫度高于343℃(650℉)時易氧化，但是其已經(jīng)被成功地用于使用溫度大于等于538℃(1000℉)的閥門中。

　　Although graphite material is prone to oxidation at temperatures above 343 ℃ (650 ℉), it has been successfully used in valves with temperatures greater than or equal to 538 ℃ (1000 ℉).

　　動加載和超時工況中的填料，由于“填料壓實”可能會導(dǎo)致其密封性能降低。這使壓蓋載荷減小，導(dǎo)致填料泄漏。這種“動加載”的過程可能是合理的選擇，包含由碟形彈簧加載的填料壓蓋，從而提供了一種維持填料壓蓋載荷的方法以幫助延長填料有效使用時間。

　　The sealing performance of fillers in dynamic loading and timeout conditions may be reduced due to "compaction of fillers". This reduces the load on the gland, resulting in packing leakage. This "dynamic loading" process may be a reasonable choice, including a packing gland loaded by a disc spring, providing a method to maintain the packing gland load to help extend the effective use time of the packing.

　　某些1/4旋轉(zhuǎn)閥門的閥桿可能會用彈性O(shè)形圈密封。這些密封圈的使用溫度范圍可能會低于PT-FE。

　　The stem of some 1/4 rotary valves may be sealed with an elastic O-ring. The temperature range for the use of these sealing rings may be lower than that of PT-FE.

　　波紋管密封閥門已經(jīng)被用于蒸汽和某種有危險/有毒的工況中，從而減少潛在的填料泄漏。在API 602中閥門的公稱尺寸為NPS1/2～2。API602除傳統(tǒng)填料外還包括波紋管閥桿密封的設(shè)計方法和試驗細節(jié)。

　　Bellows sealed valves have been used in steam and certain hazardous/toxic conditions to reduce potential packing leaks. The nominal size of valves in API 602 is NPS1/2 to 2. In addition to traditional packing, API602 also includes design methods and testing details for bellows valve stem seals.

　　5、閥蓋墊片

　　5. Valve cover gasket

　　API 600提供了幾種閥蓋墊片的選擇類型：金屬環(huán)形墊、金屬包復(fù)墊片、柔性石墨復(fù)合金屬齒形墊片(僅僅適用于150磅級)，環(huán)連接，纏繞式(大于等于300磅級)和增強型柔性石墨墊片其僅僅適于150磅級(買方批準時)。這種閥蓋墊片在-29～538℃(-20～1000℉)溫度中使用時是合理的。

　　API 600 provides several types of valve cover gasket options: metal ring gasket, metal clad gasket, flexible graphite composite metal toothed gasket (only applicable to the 150 pound class), ring connection, wrap around (greater than or equal to the 300 pound class), and reinforced flexible graphite gasket, which is only suitable for the 150 pound class (when approved by the buyer). This type of valve cover gasket is reasonable for use at temperatures ranging from -29 to 538 ℃ (-20 to 1000 ℉).

　　API 602要求閥蓋法蘭墊片類型為填充柔性石墨的纏繞式墊片，另有規(guī)定除外。設(shè)計要求防止墊片的過度壓縮。

　　API 602 requires that the valve cover flange gasket type be a wound gasket filled with flexible graphite, unless otherwise specified. Design requirements to prevent excessive compression of the gasket.

　　API 603閥蓋墊片設(shè)計與API 600相似。帶有壓縮限制和柔性石墨填料纏繞式墊片(壓力等級≥300磅級)是被允許的。API 603沒有定義一個更高的溫度要求。

　　The design of API 603 valve cover gasket is similar to API 600. Compression limited and flexible graphite filler wrapped gaskets (pressure rating ≥ 300 pounds) are allowed. API 603 does not define a higher temperature requirement.

　　本文由 良工閥門代理  友情奉獻.更多有關(guān)的知識請點擊  http://bjstar-river.com/   真誠的態(tài)度.為您提供為全面的服務(wù).更多有關(guān)的知識我們將會陸續(xù)向大家奉獻.敬請期待.

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