... 2.High heat efficiency 3.environmental protection 4.convenient maintenance 5.ISO9001-2008:SGS Chain Grate Hot Air FurnaceHigh heat transfer efficiency ... 75% Highly mechanized, stable running, and convenient operation Adaptable for various coals with heat generation value of no less than ... , feedstuffs, chemicals, building materials, minerals, and more Chain Grate Hot Air Furnace with high efficiency