G4-73, Y4-73 boiler pass, induced draft fan is suitable for power plant 670t / h or less steam boiler pass, induced draft fan systems. In no other special requirements, G4-73 can be used for mine ventilation and general ventilation. Fan transmission medium is air, the maximum temperature should not exceed 80 ℃, the medium for conveying flue draft fan, the maximum temperature does not exceed 250 ℃. Before the induced draft fan, dust removal device must be installed to minimize the fan into the dust content in flue gas, according to the general plant use, not less than 85% removal efficiency.