... ,flange type. Sizes:DN50~DN600. check valve,swing type,flange type.Design & manufacture standard: API6D, ANSI/ASME ... .Flange connection: ANSI/ASME B16.5 for NPS24,ASME B16.47A/MSS SP-44 for NPS>24.Butt-welding end dimensions: ANSI ... , A105, CF8(304), CF8M(316), CF3(304L), CF3M(316L), etc. check valve