Regarding the valve structure with dual sealing

A one-way sealed butterfly valve is a type of butterfly valve in which, when closed, the disc faces the direction of flow of the medium； The medium flows in only one direction, and an arrow on the valve body indicates the direction of flow. Attention should be paid to the flow direction of the medium during installation. A two-way sealed butterfly valve allows the butterfly disc to face either the direction of the fluid flow or away from it; therefore, there is no need to consider the direction of fluid flow during installation, and no arrows indicating the fluid flow direction are present on the valve body. The stem of a double-seal butterfly valve is subjected to greater stress than that of a single-seal butterfly valve. In the design, for butterfly valves with the same diameter and pressure, the stem diameter of a dual-seal butterfly valve is larger than that of a single-seal butterfly valve. It has good one-way sealing performance, and its range of application is the same as that of the wafer butterfly valve. The two-way sealed butterfly valve builds on the advantages of the aforementioned one-way sealed butterfly valve; its butterfly plate features a parabolic sealing geometry. Whether flow enters from the front or the back, a \"keying effect\" can be generated on the butterfly plate, allowing the sealing ring to make flexible contact and thus achieving two-way sealing.

Structurally, there should not be any major differences. From what I understand, it comes down to whether both valve seats have undergone processes such as spraying and grinding, and whether there are sealing measures between the valve seats and the valve body.

A bidirectionally sealed ball valve is characterized in that its ball valve core consists of spherical sealing discs on both sides and a wedge-shaped ball; these elements are connected to each other through inclined dovetail grooves. The wedge-shaped ball is connected to the lower end of the valve stem, which is equipped with an L-shaped groove. At the corresponding position on the bracket, there is a positioning pin that fits into this L-shaped groove. The upper end of the valve stem features an overrunning clutch, as well as a rotating wheel along with its gear set and a valve stem nut. It consists of an operating mechanism, with the valve stem in screw engagement with the nut. This practical dual-seal wedge-type ball valve features a mechanism in which, when it is opened, the dual-spherical sealing discs separate slightly from the sealing seat before the ball valve core rotates. This prevents the valve from not closing properly or from failing to open, reduces wear and extends its service life. Moreover, thanks to the dual-seal design, reliability of sealing is ensured, resulting in zero leakage from the valve. Therefore, it is highly suitable for applications with granular media. Two-way sealed butterfly valve: This product features a double-eccentric structure. It features a tighter sealing effect as it is closed, ensuring reliable sealing performance ； When activated, it ensures that the sealing pair is completely separated from contact ； It can effectively prevent any frictional wear between the sealing surfaces, thereby extending their service life. The valve shaft features a half-shaft structure, while the butterfly valve disc has a truss-like design; this gives it high strength, a large flow area, and low flow resistance.