Top entry plastic ball valve

A top entry plastic ball valve comprising a valve stem cap (1), a valve stem (2), a valve stem sealing ring (3), a valve ball sealing ring (5), a supporting ring (6) for the valve ball sealing ring, a valve ball (7), a connecting pipe (8), and a valve body (9), wherein a hollow valve ball chamber (911) is provided inside the valve body (9), characterized in that the valve body (9) is provided with a valve cover hole (912) just above the valve ball chamber (911), the width of the valve cover hole (912) is larger than the diameter of the valve ball (7), the ball valve also comprises a valve cover (4) which is provided with a valve stem shaft hole (410) for allowing the valve stem (2) to pass through and corresponds to the valve cover hole (912) so that the valve cover (4) can cover the valve cover hole (912) and can be fusion-bonded to the valve body (9);

• the right end and the left end of the valve body (9) are respectively provided with a connecting pipe seat, the side of said each connecting pipe seat fusion-welded with the connecting pipe (8) is provided with an outer end surface ring (910) which is perpendicular to the axial line of the valve body (9), and the valve body (9) and the connecting pipe (8) are in end surface welding through the outer end surface rings (910) by hot melt;
• two sides of the valve ball chamber (911) of the valve body (9) are respectively provided with a positioning end surface for the mounting ring for the valve ball sealing ring and a positioning end surface for the supporting ring for the valve ball sealing ring;
• the valve ball chamber (911) is an inner cylindrical surface coaxial with the valve body (9) and has an indentation at the valve cover hole (912), the valve cover (4) is provided with an inner cylindrical surface (41) of the valve ball chamber for supplementing the indentation, the valve body (9) is further provided with an inner cylindrical surface (92) fitted with the outer cylindrical surface of the valve ball sealing ring (5), the inner cylindrical surface (92) is in the shape of a circular ring concentric with the valve body (9), the inner cylindrical surface (92) has an indentation on the valve body (9), and the valve cover (4) is provided with an inner cylindrical surface (42) of the valve ball sealing ring for supplementing the indentation.