The APPS-type steel screw feeders are a proven and well-regarded design by customers for many years, intended for the combustion of “eco-coal” (eco-pea coal) in the 5-25mm grain size. The fuel is fed directly from the fuel storage to the burner in the boiler, systematically and evenly, which contributes to economical operation and user convenience. The burner is equipped with a toothed crown and a ring made of heat-resistant cast iron, ensuring long-lasting and reliable performance.