I. Overview: bi-pressure spherical rotary valve is the company over the years accumulated experience in valve design and manufacturing, use and maintenance, according to the urgent needs of the market out of the latest development of the patented product, is by far the large diameter valves only real entity hard seal bi-directional flow valve with butterfly, half ball, gate, globe valves, and full-featured ultra-light valve has the powerful features and benefits, while avoiding the shortcomings and weaknesses of these valves. Not only can be reliably turned off in the positive pressure, the pressure in the back pressure is much greater than the forward or reverse pressure can also be reliably turned off. The valve is short structure, small volume manufacture of large diameter, large diameter, large diameter valves, light weight, transportation, installation, maintenance and overhaul convenient, reliable operation and a series of advantages, is a major technological revolution valve industry. Second, the main purpose where the outlet end of the pump, pipe network system, recycled water systems, high sink easily flooded sewage systems, anti-backflow valve system shall be used for all two-way flow valve, this valve is widely used in metallurgy, mining, petrochemical, pipeline chemical, power, environmental protection, municipal and other industries and sectors of opening and closing, regulation.