Design and manufacture in accordance with Chinese national standards basic structure form (butterfly plate axis and valve body / seat center coincide) A. D71F4 fully lined valve body fully lined / butterfly plate fully lined / lined butterfly plate and butterfly plate axis double D with B. D71F46 fully lined valve body fully lined / butterfly plate fully lined / lining and butterfly plate as a whole C. D71F4 (46)/P half-lined type valve body fully lined / butterfly plate is Stainless steel / butterfly plate and butterfly plate shaft double D fit