短語詞組短語ball face sealing structure 球面密封結(jié)構(gòu)ball face sealing 球面密封ball head sealing 球頭密封ball valve sealing structures 球閥密封結(jié)構(gòu)Ball sealing support 球體密封支架gate valve for ball sealing 球面閘閥vacuum line sealing ball 真空管密封球metal hard sealing ball valve 金屬硬密封球閥 返回 ball sealing