阀门标准 BS EN 13959-2004 Anti-pollution check valves – —N 6 to —N 250 inclusive Family E, type A, B, C, and —.pdf [db:摘要]
阀门标准 BS 1868-1975(R1990) Steel check valves(flanged and butt-welding ends) for the petroleum,petrochemical and allied industries.pdf [db:摘要]
