良工閥門：截止閥為什么要“低進高出”？

　　Lianggong Valve: Why do globe valves have "low inlet and high outlet"?

　　在管道安裝中，截止閥是常用的閥門之一。但很多人在安裝時都會疑惑：為什么閥體上的箭頭指向“低進高出”？

　　In pipeline installation, globe valve is one of the commonly used valves. But many people may wonder during installation: why does the arrow on the valve body point to "low in, high out"?

　　截止閥的工作原理截止閥通過閥桿驅動閥瓣垂直升降實現啟閉。閥瓣落下壓緊閥座時切斷管路，閥瓣抬起脫離閥座時管路連通。

　　The working principle of a globe valve is that it opens and closes by driving the valve disc vertically up and down through the valve stem. When the valve disc falls and presses the valve seat tightly, the pipeline is cut off. When the valve disc lifts and separates from the valve seat, the pipeline is connected.

　　為什么要“低進高出”開啟省力，密封性強：閥門開啟時，介質從下方進入，壓力向上頂起閥瓣，起到助開作用，操作更省力；關閉時，閥瓣順著流向壓向閥座，即使是人力也能實現嚴密密封。

　　Why do we need "low in, high out" to open with ease and strong sealing: When the valve is opened, the medium enters from below, and the pressure pushes up the valve disc, which helps to open and makes the operation more effortless; When closed, the valve disc is pressed towards the valve seat along the flow direction, and even manual labor can achieve a tight seal.

　　延長使用壽命：閥門關閉狀態下，介質壓力被閥瓣隔絕在下方，閥蓋密封墊和閥桿填料不承壓、不受介質沖刷，填料壽命大幅延長，泄漏概率也明顯降低。

　　Extended service life: When the valve is closed, the medium pressure is isolated below by the valve disc, and the valve cover gasket and valve stem packing are not under pressure or subject to medium erosion. The packing life is significantly extended, and the probability of leakage is also significantly reduced.

　　維修方便：閥門全關且管道有旁路時，可以直接排空出口端，更換閥桿填料，無需拆卸整臺閥門。

　　Easy maintenance: When the valve is fully closed and there is a bypass in the pipeline, the outlet end can be directly emptied and the valve stem packing can be replaced without disassembling the entire valve.

　　適用場景：絕大多數常規工況，尤其是小口徑、中低壓的蒸汽、水、油管路。裝反了會怎樣？關閥困難：關閥時介質從閥瓣上方壓下來，操作扭矩大大增加。如果強行啟閉，很容易造成閥桿彎曲。

　　Applicable scenarios: The vast majority of conventional operating conditions, especially for small-diameter, medium low pressure steam, water, and oil pipelines. What would happen if I installed it backwards? Difficulty in closing the valve: When closing the valve, the medium is pressed down from above the valve disc, greatly increasing the operating torque. If forcibly opened or closed, it is easy to cause the valve stem to bend.

　　密封失效：介質壓力會持續頂著閥瓣，無法形成自密封，即使用力關閉閥門，閥瓣閥座也很難貼合，容易出現介質泄漏問題。閥門老化加速：閥門關閉狀態下介質壓力直接作用在閥桿填料上，長期沖刷會加速填料的變形和碎裂，顯著縮短閥門的使用壽命。

　　Sealing failure: The medium pressure will continue to press against the valve disc, making it impossible to form a self seal. Even if the valve is forcefully closed, the valve disc and seat are difficult to fit, which can easily lead to medium leakage problems. Accelerated valve aging: When the valve is closed, the medium pressure directly acts on the valve stem packing, and long-term flushing will accelerate the deformation and fragmentation of the packing, significantly shortening the service life of the valve.

　　“高進低出”并非完全不能用，在大口徑（DN200以上）或高壓差工況下，如果還是低進高出，巨大的介質壓力會死死頂住閥瓣，人力根本關不動，這時更適合采用“高進低出”。

　　High in and low out "is not completely unusable. In large-diameter (DN200 or above) or high-pressure differential conditions, if low in and high out are still used, the huge medium pressure will firmly press against the valve disc, making it impossible to close manually. In this case," high in and low out "is more suitable.

　　截止閥的“低進高出”適配絕大多數工況，“高進低出”是特殊場景的補充，安裝時務必參照閥體上的箭頭標識，避免裝錯流向引發安全事故。

　　The "low inlet and high outlet" of the globe valve is suitable for most working conditions. "High inlet and low outlet" is a supplement to special scenarios. When installing, it is necessary to refer to the arrow markings on the valve body to avoid installing in the wrong direction and causing safety accidents.

　　本文由 良工閥門 友情奉獻.更多有關的知識請點擊 http://m.oldercn.com/ 真誠的態度.為您提供為全面的服務.更多有關的知識我們將會陸續向大家奉獻.敬請期待.

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