阀门标准 BS 7461-1991 Specification for electrically operated automatic gas shut-off valves fitted with throughput adjusters, proof of closure switches.pdf [db:摘要]
阀门标准 BS EN 558-1-1996 Industrial valves — Face-to-face and centre-to-face dimensions of metal valves for use in flanged pipe systems.pdf [db:摘要]
