01結(jié)構(gòu)上

01 Structurally speaking

安裝空間有限的情況下選型要注意：

When selecting equipment with limited installation space, attention should be paid to:

閘閥可依靠介質(zhì)壓力緊緊與密封面緊閉，從而達(dá)到不泄露的效果。當(dāng)啟閉時(shí)閥芯和閥座密封面始終接觸并相互磨擦，因此密封面容易磨損，閘閥處于接近關(guān)閉時(shí)，管道前后壓差很大，使密封面磨損更加嚴(yán)重。

Gate valves can rely on the pressure of the medium to tightly seal with the sealing surface, thereby achieving the effect of no leakage. When opening and closing, the sealing surfaces of the valve core and valve seat are always in contact and rub against each other, so the sealing surface is prone to wear. When the gate valve is close to closing, the pressure difference between the front and rear of the pipeline is large, which makes the sealing surface wear more severely.

閘閥的結(jié)構(gòu)會(huì)比截止閥更復(fù)雜，從外形來看，同口徑情況下，閘閥要比截止閥高，截止閥要比閘閥長。另外，閘閥還有明桿和暗桿之分。截止閥沒有。

The structure of a gate valve is more complex than that of a globe valve. In terms of appearance, for the same diameter, a gate valve is taller and a globe valve is longer than a gate valve. In addition, gate valves can be divided into open stem and concealed stem. There is no shut-off valve.

02工作原理

02 Working principle

截止閥在做開啟關(guān)閉時(shí)，是上升閥桿式的，也就是說轉(zhuǎn)動(dòng)手輪，手輪會(huì)跟著閥桿一起做旋轉(zhuǎn)和升降運(yùn)動(dòng)。閘閥是轉(zhuǎn)動(dòng)手輪，使閥桿做升降運(yùn)動(dòng)，手輪本身位置不變。

When the globe valve is opened and closed, it is of the rising stem type, which means that when the handwheel is turned, it will rotate and move up and down along with the stem. The gate valve rotates the handwheel to make the valve stem move up and down, while the handwheel itself remains in the same position.

流量各不相同，閘閥要求全開或者全關(guān)，而截止閥則不需要。截止閥有規(guī)定進(jìn)口和出口方向，閘閥沒有進(jìn)出口方向要求。

The flow rate varies, and gate valves require full opening or full closing, while globe valves do not. Globe valves have specified inlet and outlet directions, while gate valves do not have requirements for inlet and outlet directions.

另外，閘閥只有全開或全關(guān)兩種狀態(tài)，閘板啟閉的行程很大，啟閉時(shí)間長。截止閥的閥板運(yùn)動(dòng)行程要小得多，并且截止閥的閥板可以在運(yùn)動(dòng)中停在某一處，做流量調(diào)節(jié)使用。而閘閥是只能做截?cái)嗍褂茫瑳]有其他功能。

In addition, gate valves only have two states: fully open or fully closed. The stroke of the gate valve opening and closing is large, and the opening and closing time is long. The movement stroke of the valve plate of the globe valve is much smaller, and the valve plate of the globe valve can stop at a certain position during movement for flow regulation. However, gate valves can only be used for cutoff purposes and have no other functions.

03性能區(qū)別

03 Performance Differences

截止閥既可以做截?cái)嗍褂茫梢宰隽髁空{(diào)節(jié)使用。截止閥的流體阻力比較大，啟閉時(shí)比較費(fèi)力，但因?yàn)殚y板距離密封面距離短，所以啟閉行程短。

Globe valves can be used for both shut-off and flow regulation purposes. The fluid resistance of the globe valve is relatively high, making it difficult to open and close. However, due to the short distance between the valve plate and the sealing surface, the opening and closing stroke is short.

閘閥因?yàn)橹荒苋_和全關(guān)，它在完全打開時(shí)，閥體通道內(nèi)的介質(zhì)流動(dòng)阻力幾乎為0，所以閘閥的啟閉會(huì)非常省力，但閘板距離密封面距離遠(yuǎn)，啟閉時(shí)間長。

Gate valves can only be fully opened and fully closed. When fully opened, the flow resistance of the medium in the valve body channel is almost zero, so the opening and closing of gate valves is very effortless. However, the distance between the gate plate and the sealing surface is far, and the opening and closing time is long.

04安裝和流向

04 Installation and Flow Direction

閘閥流向兩個(gè)方向效果都一樣，安裝沒有進(jìn)出口方向的要求，介質(zhì)可以雙向流通。截止閥則需要嚴(yán)格按照閥體箭頭標(biāo)識(shí)的方向進(jìn)行安裝，關(guān)于截止閥進(jìn)出口方向還有個(gè)明文規(guī)定，我國閥門“三化給”規(guī)定截止閥的流向一律采用自上而下。

The gate valve has the same effect in both directions, and there is no requirement for inlet and outlet directions during installation. The medium can flow in both directions. The globe valve needs to be installed strictly in the direction indicated by the arrow on the valve body. There is also a clear regulation regarding the inlet and outlet directions of the globe valve. According to the "Three Modernizations" policy for valves in China, the flow direction of the globe valve must be from top to bottom.

截止閥是低進(jìn)高出，從外觀看有明顯的管道不在一相水平線上。閘閥流道在一個(gè)水平線上。閘閥的行程比截止閥的要大。

The shut-off valve has a low inlet and high outlet, and from the appearance, there is a clear indication that the pipeline is not on the same horizontal line. The gate valve channel is on a horizontal line. The stroke of a gate valve is larger than that of a globe valve.

從流阻的角度看在全開時(shí)閘閥流阻小，載止閥流阻大。普通閘閥的流動(dòng)阻力系數(shù)約為0.08~0.12，開啟關(guān)閉力小，介質(zhì)可以兩個(gè)方向流動(dòng)。普通截止閥流動(dòng)阻力是閘閥的3-5倍。啟閉時(shí)需強(qiáng)制關(guān)閉才能達(dá)到密封，截止閥的閥芯是在完全關(guān)閉時(shí)才接觸密封面，因而密封面的磨損很小，由于流動(dòng)主力大需加執(zhí)行器的截止閥應(yīng)當(dāng)注意轉(zhuǎn)矩控制機(jī)構(gòu)調(diào)整。

From the perspective of flow resistance, when fully open, the gate valve has a smaller flow resistance, while the load check valve has a larger flow resistance. The flow resistance coefficient of ordinary gate valves is about 0.08~0.12, with low opening and closing force, and the medium can flow in two directions. The flow resistance of a regular globe valve is 3-5 times that of a gate valve. When opening and closing, it is necessary to force the valve to close in order to achieve sealing. The valve core of the shut-off valve only contacts the sealing surface when it is completely closed, so the wear of the sealing surface is very small. Due to the large flow force, the shut-off valve with an actuator should pay attention to adjusting the torque control mechanism.

截止閥在安裝時(shí)有兩種方式，一種是介質(zhì)可以從閥芯的下方進(jìn)入，優(yōu)點(diǎn)是當(dāng)閥門關(guān)閉時(shí)盤根不受壓力，可以延長盤根的使用壽命，并可以在閥前管道承壓的情況下，進(jìn)行更換盤根的工作；缺點(diǎn)是閥門的驅(qū)動(dòng)轉(zhuǎn)矩較大，是上方流進(jìn)的1倍左右，閥桿受的軸向力大，閥桿容易彎曲。

There are two installation methods for globe valves. One is that the medium can enter from below the valve core. The advantage is that when the valve is closed, the packing is not under pressure, which can extend the service life of the packing and replace it when the pipeline in front of the valve is under pressure; The disadvantage is that the driving torque of the valve is relatively large, about twice that of the upper flow, and the axial force on the valve stem is large, making the valve stem prone to bending.

所以此方式一般只適用于小口徑截止閥(DN50以下)，DN200以上的截止閥都選用介質(zhì)從上方流入的方式。（電動(dòng)截止閥一般是采用介質(zhì)從上方進(jìn)入的方式。）介質(zhì)從上方進(jìn)入方式的缺點(diǎn)正好與下方進(jìn)入方式相反。

So this method is generally only applicable to small-diameter globe valves (below DN50), while globe valves above DN200 use the method of medium flowing in from above. Electric globe valves generally use the method of medium entering from above. The disadvantage of medium entering from above is exactly opposite to that of entering from below.

05密封上

05 Sealing on

截止閥的密封面是閥心的一個(gè)小梯形側(cè)面（具體看閥心的形狀），一旦閥心脫落，相當(dāng)于閥門關(guān)閉（如果壓差大，當(dāng)然關(guān)不嚴(yán)，不過止逆效果還不錯(cuò)），閘閥是靠閥心閘板的側(cè)面來密封，密封效果不如截止閥，閥心脫落也不會(huì)像截止閥那樣相當(dāng)于閥門關(guān)閉。|

The sealing surface of a globe valve is a small trapezoidal side of the valve core (depending on the shape of the valve core). Once the valve core falls off, it is equivalent to the valve closing (if the pressure difference is large, of course, it cannot be closed tightly, but the check effect is still good). Gate valves rely on the side of the valve core gate to seal, and the sealing effect is not as good as globe valves. The valve core falling off will not be equivalent to the valve closing like globe valves. |

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