Blowers develop little higher pressure in comparison to fans. They are used for pressure below 1.65 Psi. The centrifugal blower produces energy in the air stream by the centrifugal force and a velocity to the gas by the blades. The scroll shaped volute diffuses the air and creates an increase in the static pressure by reducing the gas velocity.
The performance of a centrifugal fan varies with change in conditions like temperature, speed and density of the gas being handled. Corrections must be applied to manufacturing standards with respect to operating conditions.
FANS AND BLOWERS