The double eccentricity principle is adopted in the structure to make the valve more closed and tighter so as to achieve zero leakage. Double eccentric structure is located in the Tibetan sphere chamber when it is opened. The flow section is large and the sphere surface is not washed out. When it is opened, the sphere surface of the valve core is instantaneously detached along the valve seat. There is no friction between the valve seat and the sphere surface, and the service life is prolonged.