Such manual powder discharge butterfly valve housing aluminum dish together multi-casting (part caused by the size of the series cast iron butterfly valve housing). Switch plate with cast steel (part size series of rotating disk made of cast iron,) covered with wear-resistant polymer material. Such butterfly valve can be manual, electric or compressed air driven or gear motor drive, the drive can be mutually exchanged. Usually installed in the hopper, silo, screw conveyor outlet and a pneumatic transport pipeline. Powder discharge valve manually by two and a half body composed of high-pressure die-cast semi-valve aluminum alloy material, the rotary valve plate for polymer composite materials, or cast iron, and pre-stressed elastomer seal. Powder can be applied manually unloading valve handle all powdery and granular materials, the use of the material itself gravity valve closure and pneumatic transport of dry materials. Can be installed below the hopper, bin, silo, spiral or other type of conveyor, and connecting the pneumatic conveying line. Because of the special structure and the use of this valve engineering materials, it is always a very economical and very efficient choice.