Xiamen Dervos Valves Industry Co., Ltd

Extraordinary Suppliers of Forged Valves in China

Home > Knowledge > Content
Resilient seal structure and performance of butterfly valve
- Mar 23, 2018 -

Butterfly valves are widely used as the best device for cutting off or adjusting the flow rate in the medium pipelines of urban construction, petrochemical, metallurgy, and electric power industries. The construction of the butterfly valve is the most ideal opening and closing part in the pipeline, which is the development direction today.


First is the resilient seal butterfly valve with single eccentric structure. The bisector of the valve seat sealing cross section or the disc thickness direction is relatively eccentric with the rotation center of the valve stem, so that the butterfly valve sealing surface gradually disengages from the valve seat sealing surface during the opening process of the butterfly valve. When the butterfly plate rotates to 20~25°, the sealing surface of the butterfly plate completely separates from the sealing surface of the valve seat, so that during the opening process of the butterfly valve, the relative mechanical abrasion and extrusion between the two sealing surfaces are greatly reduced, so that the sealing performance of the butterfly valve is achieved. This design mainly relies on the elastic deformation between the butterfly plate and the valve seat to ensure the sealing of the butterfly valve.

On the basis of a single eccentric butterfly valve, the center of the valve flow channel is relatively offset from the center of rotation of the butterfly plate, so that the butterfly valve forms a cam effect during the opening process, so that the sealing surface of the butterfly plate exits the valve seat faster than the single eccentric structure. When the butterfly plate rotates to 8°~12°, the butterfly plate sealing surface completely disengages from the valve seat sealing surface. The design of this structure greatly reduces the relative mechanical wear and the extrusion deformation between the two sealing surfaces, so that the sealing performance of the butterfly valve is further improved.

On the basis of the double eccentric butterfly valve, the center line of the valve seat sealing surface forms an angle eccentricity with the centerline of the valve, so that during the opening process of the butterfly plate, the sealing surface of the butterfly plate immediately disengages from the valve seat sealing surface at the moment of opening, and The valve seat sealing surface is contacted and pressed only for a moment of closing. This unique eccentric combination fully utilizes the cam effect and completely eliminates the mechanical friction and scratches between the sealing surfaces of the butterfly valve when the valve is opened and closed, eliminating the possibility of wear and leakage. The variable-squeeze seal is a torque seal, and the adjustment of the seal specific pressure is achieved by adjusting the applied drive torque, so that the sealing performance and service life of the triple-eccentric butterfly valve are greatly improved.

image.png