Another thing I hope you can understand is that electric valve is just a driving mode of valve, butterfly valve is the main part, and solenoid valve is an accessory of electric butterfly valve, which is specially used for reversing and flow control of butterfly valve.

The valve seat is an inclined conical elliptical sealing surface, which forms a sealing pair with a regular circular elastic sealing ring embedded on the butterfly plate. The sealing ring can float in the inner diameter of the butterfly plate groove. When the valve is closed, the elastic sealing ring first contacts the short axis of the elliptical sealing surface, and gradually pushes the sealing ring inward with the rotation of the plunger valve stem, forcing the elastic ring to contact the long axis of the inclined cone surface again, eventually leading to the full contact between the elastic sealing ring and the elliptical sealing surface. Its sealing is achieved by deformation of the elastic ring. Therefore, when the valve body or butterfly plate is deformed at low temperature, it will be absorbed and compensated by the elastic seal ring, without leakage and seizure. When the valve is opened, the elastic deformation disappears immediately, and there is basically no relative friction during the opening and closing process, so the service life is long. 2) Leakage of valve: one is that when the valve and pipeline are connected by flange, the leakage is caused by the relaxation caused by the unsynchronized shrinkage between the connecting gasket, connecting bolts and connecting pieces at low temperature. Therefore, we changed the connection mode of valve body and pipeline from flange connection to welding structure to avoid low-temperature leakage.