Structural Characteristics of Single Eccentric Butterfly Valves

secureluokai December 4, 2025

1.The rotation center of the disc (i.e., the valve shaft center) coincides with the centerline of the valve body and forms an offset of dimension A relative to the sealing section of the disc. This structure, featuring an eccentric design of the disc relative to the sealing surface, is more suitable for soft sealing applications.
2.When the valve is closed, the valve seat and the disc’s sealing surface are in a state of relative interference contact. The sealing effect is mainly achieved by compressing the sealing ring to make it expand circumferentially, generating sealing specific pressure, and with the assistance of the pipeline pressure acting on the disc. Therefore, only unidirectional sealing can be realized.
3.During the valve opening process, one side of the contact surface between the disc and the valve seat detaches from the valve seat, while the other side maintains two-point contact along the axial direction of the semicircle. Repeated opening and closing are prone to causing wear of the sealing ring, thereby affecting the sealing performance. Moreover, this structure cannot achieve metal sealing.
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