Patent ID: 7896312

Claim:
A ball valve comprising: a valve body with a seat for housing a ball provided with a coaxial through-opening and able to be rotationally operated from a closed valve position into an open valve position and vice versa; two opposite end flanges which are constrained to the valve body on opposite sides of the ball and provided with a respective, coaxial, internal hole and are suitable for connection to respective pipe sections; sealing means arranged between the valve body and the ball and comprising an annular member which is coaxial with the longitudinal axis (X-X) and carries a single axial seal housed inside an associated axial seat of the annular member inside which it is partially inserted in order to interfere with the outer surface of the ball; a coaxial retaining ring axially constrained to the annular member and interfering in the transverse direction (Y-Y) with a front surface portion of the axial seal in order to retain the latter in the axial direction; and springs axially inserted inside corresponding seats of the end flange against which the springs react, wherein said axial seal is formed by a plurality of layers of sheets of pure graphite reinforced with a metal strip.