Butterfly valve with O-ring stem seals - has circular rim of valve body dovetailed with plastics valve seat ring

摘要

The butterfly valve stem (13) is located on the central line passing through the centres of the neck (24) and the valve body, and passes through the valve seat and the valve body. Each sealing assembly (15) comprises an O-ring fitted onto the valve stem (13) and a ring-shaped holder supporting the O-ring and fitted into an annular groove provided in the inner circumferential surface. The valve seat (12) is circular. In the outer circumferential surface of the seat, there is provided a dovetail groove (27) which corresponds to the dovetail (21) in the valve body (11). The valve seat (12) fits with the inner circumferential surface of the valve body (11). The valve body (11) is formed of metal, while the valve seat (12) is of synthetic rubber or plastics.