The valve body of the top mounted ball valve is designed as a whole, which will not affect the use of our valve due to the expansion and contraction of the pipeline. The ball and valve seat are both top mounted structures, and it is not necessary to remove the valve from the pipeline when maintaining the valve. The ball and valve stem can be integrated, which effectively solves the processing gap between the valve stem and the ball, and ensures the precise positioning of the ball and the protective structure against blowing out of the valve stem. The sealing form of valve stem and bonnet is not ordinary packing type seal, but packing box combined seal. The ball and valve seat can be sealed with PPL or metal hard seal according to customer requirements.