1.Rational structure ,reliable sealing,excellent performance and nice molding. 2.Co-radix alloy welded sealing surface,anti-wearing,erosion-proof abrasion-proof and prolong service life 3.There is backseat structure in the valve,so the sealing is reliable 4.Disc and sealing surface of seat utilize awl seal ,with small strength to blow down scour resistance seal credible 5.The part materials and flange dimensions may be designed according to different working condition and customer's requirement.