Ball valve seat for high temperature service

A ball valve comprising:

• a valve body having a top entry ball receiving cavity which is transverse to aligned inlet and outlet passages leading to and from said cavity;
• a cover enclosing said cavity;
• a rotatable valve stem sealably extending through said cover and connected to a rotatable ball supported in said cavity between said inlet and outlet passages and having an opening therethrough which, in one rotated position, is in co-axial alignment with said inlet and outlet passages;
• a compression spring between said cover and said ball;
• said cavity on each side of said ball defined by valve seating surfaces, each of said valve seating surfaces being canted downwardly and inwardly;
• a unitary hardened all metal ring-shaped sat located in each said valve seating surface on opposite sides of and in sealed contact with said ball, a central inner surface of each said seat defining a portion of said inlet and outlet passages respectively, each seat defined by a front ball side and a back valve body side,
• each of said seats comprising
• a concave metal seating surface on said ball side to sealably engage with said ball,
• a groove around the outer periphery thereof between said ball and said body side, and
• a bead around the outer surface of said body side for sealable contact said valve seating surface, said valve body side having a co-axial groove between said bead and a co-axial flat portion, said bead extending beyond said co-axial groove and said flat portion, whereby said bead contacts said body, and said flat portion initially being spaced from said valve body.