1.閥門類型日常應用的閥門大體上可分為手動閥門和止回閥兩大類：手動閥門在流體輸送系統中主要起截斷和接通物流、調節流量、分流的作用。手動閥門按其用途和作用分類：a)阻塞型：截止閥；b)旋轉型：球閥、蝶閥、旋塞閥；c)滑動型：閘閥；d)夾緊型：隔膜閥、膠管閥。止回閥是順流開啟、逆流關閉的自動閥門，又稱單向閥。

　　1. Valve types: Valves used in daily applications can generally be divided into two categories: manual valves and check valves. Manual valves mainly play a role in cutting off and connecting logistics, regulating flow, and diverting flow in fluid conveying systems. Manual valves are classified according to their purpose and function: a) Blocking type: globe valve; b) Rotary type: ball valve, butterfly valve, plug valve; c) Sliding type: gate valve; d) Clamping type: diaphragm valve, hose valve. A check valve is an automatic valve that opens in parallel and closes in reverse, also known as a one-way valve.

　　2. 選型原則1）閥門選擇要考慮的主要參數有：a)輸送的流體性質影響閥型和閥結構材料的選擇；b)功能要求(調節還是切斷)影響閥型選擇；c)操作條件(是否頻繁)影響閥型和閥體材料選擇；d)流動特性和摩擦損失；e)閥門大小，這可影響閥型選擇（很大的閥門只有在有限范圍的閥型中才能找到，某種特殊閥型可能買不到尺寸與其相匹配的標準閥門）；f ) 其他特殊要求：如快開、自流等。根據上述a)至c)，可用下圖選定切斷閥的基本類型。

　　2. Selection principle: 1) The main parameters to be considered when selecting a valve include: a) the properties of the fluid being transported affect the selection of valve type and valve structural materials; b) Functional requirements (regulation or cutoff) affect valve type selection; c) The frequency of operating conditions affects the selection of valve type and valve body materials; d) Flow characteristics and frictional losses; e) Valve size, which can affect valve type selection (large valves can only be found in a limited range of valve types, and a certain special valve type may not be available with a standard valve that matches its size); F) Other special requirements: such as quick opening, automatic flow, etc. Based on the above a) to c), the basic type of shut-off valve can be selected using the following diagram.

　　2）其它因素對閥門選型的影響a)對腐蝕性強、毒性為極度危害、對閥門結構材料的溶解性強、易燃易爆等介質應重點考慮閥門的密封性和耐腐蝕性，必要時可選擇隔膜閥；b)系統允許的壓力降較小時，應選用流體阻力較小的閥型如閘閥、直通的球閥等；c)要求迅速切斷時，宜選用旋塞閥、球閥、蝶閥；d)蝶閥可適用于大流量的調節；e)選用通道為L 形的兩通球閥或旋塞閥可同時起到閥門和三通的作用；選用三通球閥或旋塞閥（通道為T形）可起到兩個以上直通閥門的作用，簡化操作，使切換準確無誤，并減少所占空間；f ) 針形閥可用于微量的細調；g)需防止物料倒流時應選用止回閥；h)不同生產過程可以選擇有附加功能的閥門，如有帶夾套、帶排凈口和帶旁路的閥門，有用于防止固體微粒沉降的帶吹氣口閥門等；i ) 就地操作的閥門絕大多數用手輪，與操作點有一定距離的，可采用鏈輪或加長桿，需要時可根據所能提供的能源選擇其它動力形式：氣動、液壓、電動。例如閘閥在公稱通徑較大的管道中使用時，若兩側壓力差較大，開啟費力，需采用動力形式；j ) 對于粘性流體，漿液及帶有固體顆粒的介質宜選用旋塞閥、球閥或蝶閥。選型時應綜合考慮閥門的工藝要求、介質特性、操作溫度、操作壓力、安全及經濟的合理性，作出閥門形式的最后選擇。3. 各類閥門的結構和性能特點各種閥門的功能適用性。1)閘閥：啟閉件(閘板)由閥桿帶動，沿閥座密封面作升降運動的閥門。

　　2) The influence of other factors on valve selection: a) For media with strong corrosiveness, extreme toxicity, high solubility of valve structural materials, and flammability and explosiveness, the sealing and corrosion resistance of the valve should be given special consideration. If necessary, diaphragm valves can be selected; b) When the pressure drop allowed by the system is small, valve types with lower fluid resistance such as gate valves and straight through ball valves should be selected; c) When rapid cut-off is required, it is advisable to use plug valves, ball valves, and butterfly valves; d) Butterfly valves are suitable for regulating large flow rates; e) Choosing a two-way ball valve or plug valve with an L-shaped channel can simultaneously function as a valve and a three-way valve; Choosing a three-way ball valve or plug valve (with a T-shaped channel) can function as two or more straight through valves, simplify operation, ensure accurate switching, and reduce space occupation; F) Needle valves can be used for fine tuning in small quantities; g) Check valves should be used to prevent material backflow; h) Valves with additional functions can be selected for different production processes, such as valves with jackets, discharge ports, and bypass ports, as well as valves with blowing ports to prevent solid particle settling; The vast majority of valves operated locally use handwheels. For those located at a certain distance from the operating point, chain wheels or extension rods can be used. When needed, other forms of power can be selected based on the available energy: pneumatic, hydraulic, or electric. For example, when a gate valve is used in a pipeline with a larger nominal diameter, if there is a large pressure difference on both sides and it is difficult to open, it needs to be powered; For viscous fluids, slurries, and media with solid particles, plug valves, ball valves, or butterfly valves should be selected. When selecting a valve, the process requirements, medium characteristics, operating temperature, operating pressure, safety, and economic rationality should be comprehensively considered to make the final choice of valve form. 3. The structure and performance characteristics of various types of valves, as well as their functional applicability. 1) Gate valve: A valve whose opening and closing components (gate) are driven by the valve stem and move up and down along the sealing surface of the valve seat.

　　閘板分為平行式和楔式兩種，以后者應用最廣。閘閥有明桿和暗桿兩種，后者用于DN50以下、低壓、無腐蝕性介質的場合。①流體流經閘閥時不改變流向，當閘閥全開時阻力系數幾乎是所有閥門中最小的，適用的公稱通徑范圍、壓力溫度范圍寬，與同公稱通徑的截止閥相比，安裝尺寸較小，是石油化工生產裝置中用得最多的一種類型。②頻繁操作閥門會導致閥座表面過度磨損，因此通常只適用于不頻繁操作的情況。③不適用于含固體顆粒的流體。④若流體壓力較低，平行式閘閥的閥座力可能不足以在金屬－金屬閥座間產生滿意的密封效果。⑤只有在閥門處于半開和全關之間狀態時通過穿過圓形流道的圓盤調節流量，才會取得滿意效果。因此通常只用在兩位式場合，不適用于需要調節流量的場合。

　　Gate plates are divided into parallel and wedge types, with the latter being the most widely used. There are two types of gate valves: open stem and concealed stem. The latter is used for applications with DN50 or less, low pressure, and non corrosive media. ① When the fluid flows through the gate valve, the flow direction does not change. When the gate valve is fully opened, the resistance coefficient is almost the smallest among all valves. It is suitable for a wide range of nominal diameters, pressures, and temperatures. Compared with globe valves of the same nominal diameter, it has a smaller installation size and is the most commonly used type in petrochemical production equipment. ② Frequent operation of the valve can cause excessive wear on the valve seat surface, so it is usually only suitable for situations of infrequent operation. ③ Not applicable to fluids containing solid particles. ④ If the fluid pressure is low, the seat force of a parallel gate valve may not be sufficient to produce a satisfactory sealing effect between metal metal seats. ⑤ Only when the valve is in a state between half open and fully closed, can satisfactory results be achieved by adjusting the flow rate through a circular flow channel disc. Therefore, it is usually only used in two position situations and is not suitable for situations where flow needs to be adjusted.

　　2)截止閥：啟閉(閥瓣)內閥桿帶動，沿閥座(密封面)軸線作升降運動的閥門。截止閥的閥瓣為盤形閥瓣，節流閥的閥瓣多為圓錐流線型，特別適用于節流，可以改變通道截面積，用以調節流量或壓力。①用于調節、切斷和流通物流以及頻率操作的場合。②耐磨、密封性能可靠，可進行流量的粗調，一般多裝在泵出口、調節閥旁路和流量計上游等處。③流體阻力大，開啟和關閉所需力矩較大。④截止閥與同公稱通徑的閘閥相比，結構長度較大，最大公稱通徑限于DN250。⑤針形閥也是截止閥的一種，是帶細微錐形塞子的小口徑截止閥。可用于小流量微調或用作取樣閥。

　　2) Globe valve: a valve that is driven by the valve stem inside the opening and closing (valve disc) and moves up and down along the axis of the valve seat (sealing surface). The valve disc of the globe valve is disc-shaped, while the valve disc of the throttle valve is mostly conical and streamlined, especially suitable for throttling. It can change the cross-sectional area of the channel to regulate flow or pressure. ① Used for regulating, cutting off, and circulating logistics and frequency operations. ② Wear resistant and reliable sealing performance, capable of rough flow adjustment, generally installed at pump outlet, regulating valve bypass, and upstream of flow meter. ③ The fluid resistance is high, and a large torque is required for opening and closing. ④ Compared with gate valves of the same nominal diameter, globe valves have a larger structural length, with a maximum nominal diameter limited to DN250. ⑤ Needle valve is also a type of globe valve, which is a small-diameter globe valve with a fine conical plug. Can be used for small flow fine-tuning or as a sampling valve.

　　3)球閥和旋塞閥：球閥和旋塞閥都是啟閉件(球體，塞子)繞垂直于通路的軸線旋轉的閥門。①兩者功能相似，都是可以迅速啟閉的閥門，流體阻力小，適用于經常操作，但不宜經常作調節用。②密封性能好介質流向可任意，適用于粘性流體，漿液及帶有固體顆粒的介質。③兩者都易于適應多通道結構，使一個閥可獲得兩個、三個甚至四個不同的流道，以簡化管道系統的設計，減少閥門的用量。

　　3) Ball valves and plug valves: Ball valves and plug valves are valves whose opening and closing components (ball, plug) rotate around an axis perpendicular to the passage. ① Both valves have similar functions and can be quickly opened and closed. They have low fluid resistance and are suitable for frequent operation, but should not be used for frequent regulation. ② Good sealing performance, the flow direction of the medium can be arbitrary, suitable for viscous fluids, slurries, and media with solid particles. ③ Both are easy to adapt to multi-channel structures, allowing one valve to obtain two, three, or even four different flow channels, simplifying pipeline system design and reducing valve usage.

　　4)蝶閥：啟閉件(蝶板)繞固定軸旋轉的閥門。①啟閉迅速方便，流體阻力小，可以經常操作。②有一定調節功能，可以運送漿體，特別適用于大流量調節，但通常不用在要求泄漏最小的場合。③采用不同的密封圈形式，可以應用在較廣的壓力和溫度范圍或中等真空管道。

　　4) Butterfly valve: a valve whose opening and closing components (butterfly plate) rotate around a fixed axis. ① Quick and convenient opening and closing, low fluid resistance, and can be operated frequently. ② It has a certain adjustment function and can transport slurry, especially suitable for high flow regulation, but it is usually not used in situations where minimal leakage is required. ③ By using different sealing ring forms, it can be applied to a wide range of pressures and temperatures or medium vacuum pipelines.

　　5)隔膜閥：啟閉件(隔膜)由閥桿帶動，沿閥桿軸線作升降運動并將動作機構與介質隔開的閥門。①結構簡單，易于快速拆卸和維修。②特別適用于粘性流體、漿液和腐蝕性介質。③由于操作機構和介質通路隔開，特別適用于食品和醫藥衛生工業中的介質以及危險的介質。④不能用于介質壓力較高的場合，使用溫度取決于隔膜材料的耐溫性能，其工作溫度范圍大的為-50 ℃～175 ℃。

　　5) Diaphragm valve: A valve whose opening and closing components (diaphragm) are driven by the valve stem, move up and down along the axis of the valve stem, and separate the operating mechanism from the medium. ① The structure is simple, easy to disassemble and repair quickly. ② Especially suitable for viscous fluids, slurries, and corrosive media. ③ Due to the separation between the operating mechanism and the medium pathway, it is particularly suitable for media and hazardous media in the food and pharmaceutical industries. ④ It cannot be used in situations with high medium pressure. The operating temperature depends on the temperature resistance of the diaphragm material, and its working temperature range is from -50 ℃ to 175 ℃.

　　6)針形閥：啟閉件是帶細微錐形塞子的小口徑截止閥，可分為簡單地往下擰，傾斜地往下擰和出口流與主流成直角三種類型。

　　6) Needle valve: The opening and closing member is a small caliber globe valve with a fine conical plug, which can be divided into three types: simple downward tightening, inclined downward tightening, and outlet flow at a right angle to the main flow.

　　7) 膠管閥：由撓性管組成伸縮閥體的閥門，該管可機械或借閥體外流體壓力夾緊。①適用于腐蝕性介質、漿液、帶懸浮顆粒的流體。②結構簡單，便于維修。

　　7) Rubber hose valve: a valve composed of a flexible tube with a telescopic valve body, which can be mechanically or clamped by fluid pressure outside the valve body. ① Suitable for corrosive media, slurries, and fluids with suspended particles. ② The structure is simple and easy to maintain.

　　8)止回閥：啟閉件(閥瓣)借介質作用力，自動阻止介質逆流的閥門。①一般用于防止流體逆向流動。②常用的有旋啟式，升降式兩種，旋啟式應用于大口徑管道上，一般安裝在水平管道上，也可安裝在垂直或傾斜管道上，此時流體應自下而上流動。升降式用于小口徑管道，只能安裝在水平管道上。③帶緩閉裝置和阻尼機構的止回閥可利用管路內介質進行緩沖，達到消除或減小在止回閥關閉的瞬間由于壓力迅速提高時對管路系統所產生的“水錘”作用，保護管路和防止泵倒流。

　　8) Check valve: a valve whose opening and closing components (valve disc) automatically prevent the reverse flow of the medium by the force of the medium. ① Generally used to prevent reverse flow of fluids. ② There are two commonly used types: swing type and lift type. Swing type is applied to large-diameter pipelines and is generally installed on horizontal pipelines, but can also be installed on vertical or inclined pipelines. At this time, the fluid should flow from bottom to top. The lifting type is used for small-diameter pipelines and can only be installed on horizontal pipelines. ③ A check valve with a buffering device and damping mechanism can use the medium in the pipeline to buffer and eliminate or reduce the "water hammer" effect on the pipeline system caused by the rapid increase in pressure at the moment of the check valve closing, protecting the pipeline and preventing pump backflow.

　　9)底閥：安裝在泵吸入管端，以保證吸入管內被流體充滿的止回閥。

　　9) Bottom valve: a check valve installed at the end of the pump suction pipe to ensure that the suction pipe is filled with fluid.

　　10)節流閥：通過啟閉件(閥瓣)改變通路截面積，以調節流量、壓力的閥門。

　　10) Throttle valve: a valve that adjusts flow and pressure by changing the cross-sectional area of the passage through an opening and closing element (valve disc).

　　4. 閥門材料的選擇對于高溫工況的閥門，常用的有A217-WC6(鑄件)、A182-F11(鍛件)和A217-WC9(鑄件)、A182-F22(鍛件)。由于WC9、F22屬于2-1/4Cr-1Mo系列，相比屬于1-1/4Cr-1/2Mo系列的WC6、F11含有更高的Cr、Mo，所以具有更好的抗高溫蠕變性能。1) 對于小口徑(DN≤40)一般選用鍛件，大口徑(DN>40)一般選用鑄件。鍛件閥體的端法蘭，應該優先選擇整體鍛制閥體，如果法蘭是焊接在閥體上，則對焊縫應該進行100%射線檢驗。2)對焊和承插焊碳鋼閥體的含碳量應不大于0.25%，并且碳當量應不大于0.45%。3) 常用材料的選取：注：當奧氏體不銹鋼工作溫度超過425℃時，含碳量不應小于0.04%，熱處理狀態為大于1040℃快冷(CF8)和1100℃快冷(CF8M)。4) 當流體腐蝕性強，普通奧氏體不銹鋼不能使用時，應考慮一些特種材料，如904L、雙相鋼(如S31803等)、蒙乃爾和哈氏合金等。

　　4. Selection of Valve Materials For valves operating under high temperature conditions, commonly used ones include A217-WC6 (castings), A182-F11 (forgings), and A217-WC9 (castings), A182-F22 (forgings). Due to the fact that WC9 and F22 belong to the 2-1/4Cr-1Mo series, WC6 and F11, which belong to the 1-1/4Cr-1/2Mo series, contain higher levels of Cr and Mo, thus exhibiting better high-temperature creep resistance. 1) For small diameters (DN ≤ 40), forgings are generally used, while for large diameters (DN>40), castings are generally used. The end flange of the forged valve body should prioritize the overall forged valve body. If the flange is welded to the valve body, the weld seam should undergo 100% radiographic inspection. 2) The carbon content of butt welded and socket welded carbon steel valve bodies should not exceed 0.25%, and the carbon equivalent should not exceed 0.45%. 3) Selection of commonly used materials: Note: When the working temperature of austenitic stainless steel exceeds 425 ℃, the carbon content should not be less than 0.04%, and the heat treatment state should be greater than 1040 ℃ rapid cooling (CF8) and 1100 ℃ rapid cooling (CF8M). 4) When the fluid corrosiveness is strong and ordinary austenitic stainless steel cannot be used, special materials such as 904L, duplex steel (such as S31803), Monel and Hastelloy alloys should be considered.

　　5. 閥門內件材料內件主要是指閥門關閉件的密封面和閥桿、襯套（上密封座），在國外常以trim表示內件。內件材料的選用原則是根據主體材料的情況、介質特性、結構特點以及零件所起的作用、受力情況綜合考慮的。對于常規的通用閥門在標準已規定了內件材料或規定了幾種材料由設計者根據具體情況選用。對于一些有特殊要求的閥門，如高溫、高壓、介質有腐蝕等工況條件，則需按工況條件選擇內件材料。常用閥門內件材料的組合

　　5. The material of valve internals mainly refers to the sealing surface, valve stem, and liner (upper sealing seat) of the valve closing element. In foreign countries, trim is often used to represent internals. The selection principle of internal materials is based on the condition of the main material, the characteristics of the medium, the structural features, as well as the role and stress situation of the parts. For conventional universal valves, the standard has specified the internal material or several materials to be selected by the designer according to specific circumstances. For valves with special requirements, such as high temperature, high pressure, and corrosive media, the internal material should be selected according to the operating conditions. Combination of commonly used valve internals materials

　　6. 閥門的軟密封材料軟密封的密封性一般都能達到很高，而硬密封則要根據要求可高可低；軟密封需要防火，因為在高溫下，軟密封的材質會出現泄漏，而硬密封則沒這個問題；硬密封一般可以做到很高的壓力，軟密封則不行；軟密封由于所流介質的問題，有些場合是不能用的（比如一些腐蝕性介質）；最后硬密封閥門一般比軟密封的貴。軟、硬密封球閥選用主要依據工藝介質，溫度及壓力，一般介質含有固體顆粒或具有磨損或溫度高于200度最好選用硬密封的，口徑大于50閥門壓差較大還考慮開啟閥門力矩大小，力矩較大時應選用固定硬密封球閥，無論軟硬密封其密封等級都可以達到6級。

　　6. Soft sealing materials for valves generally have high sealing performance, while hard seals can be adjusted according to requirements; Soft seals need to be fire-resistant because at high temperatures, the material of the soft seal may leak, while hard seals do not have this problem; Hard seals can generally achieve high pressure, while soft seals cannot; Soft seals cannot be used in some situations due to the problem of the flowing medium (such as some corrosive media); Hard sealed valves are generally more expensive than soft sealed ones. The selection of soft and hard sealed ball valves is mainly based on the process medium, temperature, and pressure. Generally, if the medium contains solid particles or has wear or temperature higher than 200 degrees, it is best to choose hard sealed valves. If the diameter is greater than 50 and the pressure difference is large, the opening torque of the valve should also be considered. When the torque is large, a fixed hard sealed ball valve should be selected. Regardless of whether it is soft or hard sealed, its sealing level can reach level 6.

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