Three eccentric metal seal butterfly valves are used in metallurgy, light industry, electric power, petrochemical industry, gas waterways and other fields.
The eccentric 1 valve shaft is located behind the seat shaft so that the seal can completely and closely surround and contact the entire seat.
The center line of eccentric 2 valve shaft is braided away from the center line of pipeline and valve, which avoids the interference of valve opening and closing.
The cone axis of eccentric 3 valve seat deviates from the center line of valve shaft, which can eliminate friction during closing and opening, and achieve uniform compression sealing around the whole valve seat.
The three eccentric butterfly valve has two-way bubble free tight closing performance. This geometry ensures that the disc seal contacts the valve seat only in the closed position, so there will be no friction or wear, and a torque will be generated to make the elastic seal have sufficient "welding" performance and ensure the uniformity of seal contact.
Based on the double eccentric butterfly valve, an angular offset is formed between the center line of the valve seat and the center line of the valve body, so that during the opening process of the butterfly valve, the sealing surface of the butterfly plate immediately separates from the sealing surface of the valve seat at the moment of opening, and contacts and compresses the sealing surface of the valve seat at the moment of closing. When it is fully opened, a gap y with double eccentric sealing butterfly valve is formed between the two sealing surfaces. The design of this kind of butterfly valve completely eliminates the mechanical wear and scratch between the two sealing surfaces, and greatly improves the sealing performance and service life of the butterfly valve.
(1) As standard, the valve seat adopts Cr13 alloy or Stellite hard surface.
(2) The sealing gasket adopts spiral disk stainless steel + graphite to realize zero leakage.
(3) The torque during closing produces a seat force that acts uniformly around the entire circumference. The elastic seal is bent and full of vitality, maintains the shape of the valve seat, and the compressive force acts evenly along the circumference, so that the valve can realize two-way close. The elasticity of the seal enables the valve body and disc to contact and expand, avoiding the risk of blockage due to temperature fluctuation. This device can adjust and align itself.