ANSI bellows seal stop valve characteristic: Double-decked corrugated pipe, service convenient, dual seals, position instruction; application situation: The power plant, the natural gas, the ammonia, the vacuum, the freezing systematic, the hot oil system, the hot water. Design manufacture standard: DIN 3352; fac to fac standard: EN 558; flange standard: EN 1092; examination experiment standard: EN 12266.