Impeller feeder has rigid type and elastic type. It is also called star dust discharge valve. It is widely used as discharge device of all kinds of dust removing equipment in building material, metallurgy, chemical industry, power generating plant etc and of different kinds of mills, driers, silos etc. Depending on the gravity of material and force of work structure of feeder, it makes material in silo discharge into next device continuously and evenly. The valve is welded by steel plate. The abrasion of impeller is good. The rigidity connection of impeller and driving shaft is good. It is characterized by tight structure, reliable working, portable and energy saving. The valve is composed of valve body, driving shaft, impeller and reducer etc. The motor of reducer will drive driving shaft and the rotation of impeller, thus the discharge is finished.