Ventilation and air conditioning apparatus; electric motor-driven fans, ventilating fans and electrically powered blowers for ventilation for commercial and industrial purposes; structural replacement parts for the aforesaid goods, in particular ventilating fan propellers, ventilating fan blades, fan propellers, fan blades, blower propellers, blower housings, inflow nozzles, outflow nozzles, diffuser housings; fittings specially adapted for electric motor-driven fans, ventilating fans and ele...