Manual flapper valve, flapper valve star, star unloader, chained cinder valve, manual valve flapper mouth to make a choice based on the shape of the discharge. Red environmental protection equipment manual flapper valve durability, flow resistance, small size, light weight, widely used. Manual flapper valve sealing structure can be divided into soft seal and hard seal structure. Good technology, compact structure, sealing seat structure for manufacturing activity, anti-wear and automatic compensation function, thus longer life. Manual flapper valve unloader mostly for supporting the use of two round mouth into side port. Red environmental protection equipment manual flapper valve compact structure, wear a small amount of leakage, a simple, flexible movement, effort, etc., can work, according to the mouth at a high temperature, high dust, magnetic environment unloader shape choice. Using high-quality carbon steel welded, widely used in metallurgy, carbon, chemicals, building materials and other industries. Flue gas piping system used for flue gas cleaning system regulation, switching effect.