Difference between fan and blower

The difference between centrifugal fan and blower lies in the pressure ratio it can achieve. Generally speaking, the blower can produce a higher pressure ratio. According to the American Society of Mechanical Engineers (ASME), a specific ratio – the ratio of discharge pressure to suction pressure – is used to define fans, blowers and compressors. The ratio of fan is as high as 1.11, the ratio of blower is 1.11 to 1.20, and the ratio of compressor is greater than 1.20. Generally, due to the high pressure involved, the structure of blower and compressor is much stronger than that of fan.