... Second burning technology 2) Supply warm and clean air for the chicken or pig house 3) Coal ... drying material.Component: Body of furnace, air inlet, air outlet, furnace gate, ventilator, air blower, chimney.Features:1. It has the ... advantages of rapid providing of clean hot air efficiently;2. Second burning technology is adopted in ... manual temperature control. 9RFL-20D Coal-fired Air Heater