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真(zhen)空(kong)止(zhi)回閥又(you)稱真(zhen)空(kong)單向閥或真(zhen)空(kong)逆止(zhi)閥，其作用(yong)是防止(zhi)管路中的(de)介質倒流(liu)。真(zhen)空(kong)止(zhi)回閥也屬于止(zhi)回閥類。 　　

真空止(zhi)(zhi)回(hui)閥的(de)啟(qi)閉(bi)件靠介質(zhi)(zhi)流(liu)動(dong)(dong)的(de)力量自(zi)行開啟(qi)或關(guan)閉(bi)，以(yi)防止(zhi)(zhi)介質(zhi)(zhi)倒(dao)流(liu)。止(zhi)(zhi)回(hui)閥屬于自(zi)動(dong)(dong)閥類，主要用于介質(zhi)(zhi)單向流(liu)動(dong)(dong)的(de)管道上，只(zhi)允許介質(zhi)(zhi)向一個方向流(liu)動(dong)(dong)，以(yi)防止(zhi)(zhi)發生(sheng)事故。 　　

真(zhen)空(kong)止(zhi)(zhi)回(hui)(hui)(hui)閥(fa)按結構(gou)劃分(fen)(fen)，可(ke)分(fen)(fen)為升降式(shi)止(zhi)(zhi)回(hui)(hui)(hui)閥(fa)、旋啟式(shi)止(zhi)(zhi)回(hui)(hui)(hui)閥(fa)和(he)蝶式(shi)止(zhi)(zhi)回(hui)(hui)(hui)閥(fa)三種(zhong)(zhong)。升降式(shi)止(zhi)(zhi)回(hui)(hui)(hui)閥(fa)可(ke)分(fen)(fen)為立式(shi)和(he)臥式(shi)兩種(zhong)(zhong)。旋啟式(shi)止(zhi)(zhi)回(hui)(hui)(hui)閥(fa)分(fen)(fen)為單(dan)瓣式(shi)、雙瓣式(shi)和(he)多(duo)瓣式(shi)三種(zhong)(zhong)。蝶式(shi)止(zhi)(zhi)回(hui)(hui)(hui)閥(fa)為直通式(shi)、以上(shang)幾種(zhong)(zhong)止(zhi)(zhi)回(hui)(hui)(hui)閥(fa)在連接(jie)形(xing)式(shi)上(shang)可(ke)分(fen)(fen)為螺紋連接(jie)、法蘭(lan)連接(jie)和(he)焊接(jie)三種(zhong)(zhong)。