There are different types of eccentric sealing butterfly valves, and the fields of application and their characteristics are naturally different. But fundamentally, the basic principle of eccentric sealing butterfly valve has the same purpose. Our company produces eccentric sealing butterfly valves of various materials. There are single eccentric sealing butterfly valve, double eccentric sealing butterfly valve and triple eccentric sealing butterfly valve.
Structural schematic diagram of single eccentric butterfly valve:
Structural features of single eccentric butterfly valve:
1. The center of rotation of the disc (ie, the center of the valve shaft) is located on the center line of the valve body, and an A-dimension offset is formed on the sealing section of the valve plate. The single eccentric butterfly valve is that the rotation center of the disc plate is on the center line of the valve body, and the valve plate deviates a distance from the sealing surface, which is suitable for soft sealing.
2. When the valve is closed, the valve seat and the sealing surface of the valve plate are in a relatively interference contact state. To achieve the sealing, the sealing is mainly achieved by pressing the sealing ring to expand it in the peripheral direction to generate sealing specific pressure and pipeline pressure on the valve plate. The force to make it reach the seal, so it can only be sealed in one direction.
3. When the valve is opened, the contact side of the valve plate and the valve seat is separated from the valve seat, and the other side is always in two-point contact along the axial direction of the semi-circle. Repeated opening and closing of the sealing ring is easy to damage, which affects the sealing performance. Metal sealing is not possible.
4. From the geometrical point of view, it can be clearly seen that X does not exist in the above figure, and in turn, there is a certain amount of interference.
Double eccentric butterfly valve structure schematic diagram:
Structural features of double eccentric butterfly valve:
The center of rotation of the valve plate (that is, the center of the valve shaft) forms a dimension A offset from the valve plate sealing section, and forms a dimension B offset from the center of the valve body.
Three eccentric butterfly valve structure schematic diagram:
Structural features of triple eccentric butterfly valve:
The center of rotation of the valve plate (ie the center of the valve shaft) forms an A offset on the sealing section of the valve plate, and forms a b offset with the center of the valve body; the centerline of the valve body sealing surface and the centerline of the valve seat (ie, the centerline of the valve body) An angular offset of angle β is formed.