Suction is applied at the hot operation zones of the pre-treatment units which removes the generated stem from the system. Cases may happen where such steam may not be released to the open air since it may contain aggressive acids or alkali. In such cases, air washer equipment is recommended to be in place with the discharging air duct system.

The task of the air washer is to neutralise the acids and alkali in the steam. There is a spraying crown integrated in the air washer unit which sprays fresh water in the way of the air. The sprayed water forwards the water with acid and alkali aggregate to the tank of the air washer. The vapour possible to be remaining in the air will be blocked by the drop separator unit bolt in the air duct, therefore only cleaned water can pass in the discharge air duct.

Water needs to be replaced in the air washer tank at certain intervals.