[ Ventilators being parts of machines, in particular chemical ventilators, process ventilators, induced draught ventilators; vacuum ventilators being parts of machines, circulation fans being parts of machines, ] exhaust fans being parts of machines [, regenerative gas fans being parts of machines; turbo power operated blowers being parts of machines, circulation ventilators being parts of machines, flue gas ventilators being parts of machines, relative wind fans being parts of machines, air ...