Ventilators being component parts of industrial plants, chemical plants, petrochemical plants, refineries, engineering industry plants, wood industry plants, oil and gas industry plants, iron and steel industry plants and emission control plants, in particular chemical ventilators, centrifugal ventilators, process ventilators and induced draught ventilators; vacuum ventilators, electric circulation fans, and exhaust fans for motors and engines; regenerative gas fans being component parts of i...