Eccentric butterfly valve structure classification
Single eccentric butterfly valve
In order to solve the extrusion problem of butterfly plate and seat of concentric butterfly valve, single eccentric butterfly valve is produced. Its structural feature is that the shaft of valve stem deviates from the center of butterfly plate, so that the upper and lower ends of butterfly plate no longer become rotary axis, disperse, and reduce the excessive extrusion between the upper and lower ends of butterfly plate and seat.
Double eccentric butterfly valve
On the basis of single eccentric butterfly valve further improved forming is currently the most widely used double eccentric butterfly valve.Its structural characteristics are deviated from both the center of the disc and the center of the body in the shaft of the valve stem.The effect of double eccentric valve is opened after the butterfly plate can quickly off the seat, greatly eliminate the butterfly plate and the seat unnecessary excessive extrusion, scraping phenomenon, reduce the open resistance distance, reduce wear, improve the seat life
Triple eccentric butterfly valve
High temperature resistance, must use a hard seal, but a large amount of leakage;For zero leakage, a soft seal must be used, but not resistant to high temperatures.In order to overcome the double eccentric butterfly valve this contradiction, and the third eccentric butterfly valve.And the so-called third eccentric, is the shape of the sealing pair is not a cone, but a cone.
Eccentric butterfly valve features
The butterfly valve and the upper and lower valve shafts are connected by special-shaped holes and special-shaped shafts. In the opening and closing process of the butterfly plate, the function of the butterfly plate floating up and down and left and right without pin links is realized, which reduces the interference zone between the butterfly plate and the valve seat and thus greatly reduces the torque.The floating structure of the butterfly plate realizes the manufacturing technology of single eccentricity and the function of changing eccentricity.
The inner chamber of the valve body is provided with anti-butterfly plate over-position baffle block to ensure that the butterfly plate is not in place when closed.
Bushing is used to protect the upper and lower axle hole of valve chamber and the upper and lower axle hole of butterfly plate to prevent the large particles in the medium from entering the axle hole of valve.