the sealing surface of three eccentric butterfly valve is obliquity and the sealing ring of valve base is made of hard metal built-up welding, which has no theoretical abrasion during the process of opening and close, so the service life is long. Because the sealing ring of the valve is made of stainless steel which has no other inlayers ,so there is no pollution and is of anti-fire performance. The surface of the valve is paint with epoxy which doesn't have poison or pollution and can resist corrosion and scour, it has come to Europe environmental standards