The hot air generator shall consist of three segments, which is, the combustion chamber, the conical venturi mixing chamber and the outlet chamber. The circular combustion chamber will have the burner wall at one end. The burner shall be fitted on to the burner wall at one end of the combustion chamber that will fire directly into the chamber.
The combustion chamber shall be made of two concentric shells wherein the inner shell lined with refractory material, will work as combustion chamber and the dilution air will be forced through the annular gap available between the two concentric shells.
Dilution air is forced into the air heater with the help of a forced draught centrifugal fan that will mix with the products of combustion in the conical venturi mixing chamber, also lined with insulation material. Hot air at desired temperature and quantity will emanate from the outlet chamber that is also normally lined with insulation material.
Hot Air Generators
In Direct Fired Hot Air Generator, the combustion chamber is enclosed in a concentric shell with suitable lining. The fresh air from dynamically and statically balanced blower is fed to the chamber tangentially. The air envelopes the combustion chamber and absorbs the radiant heat from its surface and then mixes with completed combustion gases in a conical chamber. The hot air, thus generated is let out from hot air generator at controlled temperature to the process. Such heating systems have very high thermal efficiency with proper insulation.