Continuous efforts have been made to address the sealing issue of butterfly valves, with significant results achieved, but the problem still persists

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　　A relatively advanced type of butterfly valve is the triple-eccentric metal hard-seal butterfly valve, in which the valve body and the valve seat are integrated components, with the sealing surface of the valve seat being clad with heat-resistant and corrosion-resistant alloy materials. Multi-layer soft folded sealing rings are fixed on the valve plate; compared to traditional butterfly valves, this type of butterfly valve offers advantages such as high temperature resistance, easy operation, friction-free opening and closing. When closed, the sealing is enhanced as the torque applied by the actuation mechanism increases, which improves the sealing performance of the butterfly valve and extends its service life. However, research on German ARCA butterfly valves has revealed that the following problems still exist during use: First, since the multi-layered soft and hard gasket assembly is fixed to the valve disc, when the valve disc is in the open position, the medium exerts direct erosion on its sealing surface; as a result, the soft sealing strip located in the metal interlayer is damaged by this erosion, which directly affects the sealing performance. 　　II. Due to structural constraints, this design is not suitable for valves with a diameter of DN200 or less, as the overall structure of the valve disc is too thick, resulting in high flow resistance. Guilong Valves | http://www.shglfm.cn/ III. Due to the principle of the triple-eccentric structure, the sealing between the sealing surface of the valve disc and the valve seat is achieved by using the torque from the actuation mechanism to press the valve disc against the valve seat. In the forward flow state, the higher the medium pressure, the tighter the sealing compression. When the flow medium flows in reverse, as the pressure of the medium increases and the unit normal pressure between the valve plate and the valve seat becomes less than the pressure of the medium, leakage in the seal begins. High-performance triple-eccentric two-way hard-sealed butterfly valve, characterized by: http://www.arca-valve.com.cn/ The valve seat seal ring is composed of multiple layers of stainless steel sheets on both sides of a flexible T-shaped seal ring. The sealing surfaces of the valve plate and the valve seat are of a slanted cone shape, with heat-resistant and corrosion-resistant alloy materials welded onto the slanted cone surface of the valve plate ； A structure in which a spring fixed between the adjustment ring pressure plates is assembled with the adjustment bolts on the pressure plates. 　　This structure effectively compensates for the tolerance gaps between the shaft sleeve and the valve body, as well as the elastic deformation of the valve stem under medium pressure, thereby resolving the sealing issues that arise during two-way media transfer with this type of valve. A sealing ring is formed using multiple layers of stainless steel sheets on both sides of a flexible T-shaped structure, combining the advantages of both metal hard sealing and soft sealing; it provides zero-leakage sealing performance in both low-temperature and high-temperature conditions. This is also related to the quality of the valves; choosing high-quality valves can significantly reduce such problems. For example: German ARCA control valves, Guilong valves