The butterfly plate of the soft sealing butterfly valve is installed in the diameter direction of the pipeline. In the cylindrical passage of the butterfly valve body, the disc-shaped butterfly plate rotates around the axis, and the rotation angle is between 0° and 90°. When the rotation reaches 90°, the valve is fully opened. The characteristics of the new high-life stainless steel butterfly valve and the problems in the use of the butterfly valve, this type of valve should generally be installed horizontally in the pipeline. According to the connection mode, the soft sealing butterfly valve can be divided into flange soft sealing butterfly valve, wafer soft sealing butterfly valve, welding soft sealing butterfly valve.
1. Since the multi-layer soft and hard stacked sealing ring is fixed on the valve plate, when the valve plate is normally open, the medium will form a positive scouring on its sealing surface. The soft sealing band in the metal sheet sandwich will directly affect the sealing performance after being scoured.
2. Restricted by structural conditions, this structure is not suitable for valves with a diameter below DN200, because the overall structure of the valve plate is too thick and the flow resistance is large.
3. Due to the principle of the triple eccentric structure, the seal between the sealing surface of the valve plate and the valve seat depends on the torque of the transmission device to press the valve plate against the valve seat. In the positive flow state, the higher the medium pressure, the tighter the sealing extrusion. When the flow channel medium flows back, as the medium pressure increases, the unit positive pressure between the valve plate and the valve seat is less than the medium pressure, the seal begins to leak.
