As the manufacturer of drying systems, Binder began at an early stage with the construction of air heaters. Usually, fan burners for oil or gas are used. Depending on the application, a differentiation takes place between direct and indirect firing.

Here, the process air remains free from smoke gas, as the heat exchange takes place via heat exchange areas only. The indirect air heater is therefore suitable above all in the food industry, but also in the chemicals industry, where smoke gas is undesirable.
The indirect air heater consists of a combustion chamber with a subsequent smoke gas/air heat exchanger. When heating air, we differentiate between a counterflow and a uniflow principle, depending on the application. According to the uniflow principle, the air to be heated is first directed round the combustion chamber before cooling down the smoke gas via the tube heat exchanger and leaving the air heater at the desired end temperature. An outer casing with insulation prevents heat loss.

Binder uses highly heat-resistant materials for the manufacture of the combustion chamber and the heat exchanger. The heat exchangers can be directly integrated into the dryer according to requirements. Process air temperatures up to 600°C are possible.

mixes the process air with the smoke gas. This type of air heater is particularly used in industrial application in conjunction with natural gas burners, where the combustion gases do not represent a danger of contamination for the product to be dried.

Combustion takes place in the combustion chamber similar to the indirect air heater. The process air is first directed round the combustion chamber via an external guide tube until it is finally mixed with the smoke gas as it leaves the air heater. The entire combustion energy is fed to the drying plant using this technology. The efficiency is therefore 100%. Due to the special air guidance inside the Binder air heater, an even temperature level in the air flow is achieved. The highly heat-resistant steels of the combustion chamber guarantee a long service life.

Usually, fan burners are used for both types of air heater. Natural gas, liquid gas, or gas gained in biogas plants is used as fuel, which is particularly interesting for communal sewage plants for an economical point of view.
Oil burners are also used for light or bunker oils as an alternative to pure gas burners. For economic reasons, dual-fuel burners can also be used i.e. gas or oil burners in alternating operation.