Direct and Indirect Air Heaters

In indirect air heaters, contact between the combustion air and the product is prevented. In direct air heaters, combustion air is directly supplied to the product.

For example ,In the food industry, it is necessary to remove the water from milk to dry it and turn it into milk powder. The required heat for this drying process is obtained through a burner. Due to hygiene reasons, it is undesirable for harmful gases in the combustion gas to come into contact with the product. Therefore, indirect air heaters are often preferred in the food industry. Additionally, these types of air heaters, which come into contact with food, are generally made of stainless steel.

Especially in processes and locations that require hot air or hot drying air, especially where the content of the gas is not crucial, direct air heaters are used. 

Both types of air heaters use burners as the heat source. These burners can be Natural Gas Fired, Liquid Fuel Fired, or burners capable of burning both types of fuel.”

We, as Eralp Boiler, manufacture both direct and indirect air heaters.