Directly-fired air heater

摘要

A directly-fired air heater for drying harvested agricultural crops has a combustion chamber for liquid fuels in series with a combustion chamber for solid fuels with a common heat exchanger. Between the two combustion chambers, there is connected a postcombustion device for solid fuels with a secondary-air supply. The waste gas pipe of this postcombustion device opens directly into the combustion chamber for solid fuels. Both combustion chambers for solid and liquid fuels can without conversion be operated together or separately from one another so that for example the liquid fuel chamber only contributes the quantity of heating energy which is not made available by the solid combustion chamber. This makes possible the use of native fuels.