The sealing principle consists of a stainless steel valve flap with a spherical surface and a non metallic material sealing ring which is wear-resistant, high temperature resistant and resilient, and has good sealing performance and long service life. Horizontal vertical pipe can be installed, can be used for petroleum, chemical, water supply and drainage system to control the flow of media in the system back, and automatic shutdown function. Is a kind of ideal non leakage energy saving check valve.