Jacket type ball valve door overview DYQ340H jacket type ball valve door, consists of the valve body, wedge sphere, valve seats, valve cover, valve stem, on the side of the valve body is equipped with the opening up of wedge sphere mounting holes, and the valve rod connected with wedge sphere linkage, in the lower part of the valve rod set equipped with spring, spring to wedge sphere as the first base, according to the valve stem of convex platform as a base, the upper end of the valve rod convex platform with a seal between the valve cover, between the valve cover and valve body is equipped with sealing gasket, described in the section of seal for wedge, convex sets or referred to in the valve cover is equipped with corresponding bench surface and seal with wedge seal, bench surface set on the upper face of convex sets, best use of elastic springs or medium pressure used to seal between the valve stem and valve cover section for wedge seals and sealing surface wedge seal, by using the theory of oblique wedge to make seal face more closely, the sealing effect is better