Type G4-73 and y4-73 fans Mainly used  in Steam boiler,G4-73 may be used in mines for Ventilation.The medium carried by ventilation fan is air and the max temperature must be below 80 degrees celsius;fue gas is carried by draught fan and the top  temperature can not exceed 250 degrees celsius. A dust collection device Should be mounted in front of the draught fan to reduce the dust that may enter the fan.