A butterfly valve of large diameter which comprises a body with a substantially cylindrical inner bore, internally lined with a ring that terminates at lateral flanks of the valve; a butterfly pivotally mounted in the body by means of valve spindles that pass through the body and the ring; wherein the body includes at least two annular grooves that are coaxial with respect to the bore; the ring being constructed with several aligned sections, such as two curvilinear sections and a plurality of rectilinear sections; wherein the ends of the sections are formed and vulcanized to shape after having been aligned; the ring further including, on its side adjacent the body, at least two annular tenons with heads that respectively engage the grooves, these tenons being smaller than the groove inlets; an empty space being provided between the tenons and the grooves, filled at the time of assembly with a plastic material that hardens by polymerization, for example an epoxy resin. Optionally, the body may have passages therein for the valve spindles, the ring may further include a flange, and screws may be provided at the ends of the passages for regulating the axial compression of the flange about the valve spindles.
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