One normal axial fan operating at maximum efficiency can achieve a velocity pressure (pбµҐ) of up to 0.5psi (в‰€3,500N/mВІ). each fan in the sequence increases pressure over the previous fan until you have achieved the pressure required. Multi-stage fans are used where a very high outlet pressure is required.

the lower the air resistance, the faster the rotation and the greater the flow. All fans of a given power rating will rotate at a speed commensurate with the air resistance, i.e. Multi-stage fans are normally used to increase outlet pressure, but are comparatively expensive.ДЄirflow through the impeller is generated by rotating profiled blades ( Fig 1) in a cowling that cut into the air at their inlet tip pushing the air back along the blade and, in the case of centrifugal fans, also from centrifugal forces generating a partial vacuum on the inlet side of the fan due to the entrained air being thrown outwards according the relationship a = vВІ/rДЄpart from the electrical and mechanical components, the efficiency of a fan is to a large extent dependent upon the shape and orientation of the blades. For example, an impeller fan has a higher efficiency when transporting clean (light air) at high flow rates (high speed), whereas a straight-bladed Sirocco fan is more efficient when propelling heavy gases (vapours and particulates) because centrifugal force is the dominant driver. Differences such as efficiency or flow rate occur in the type of fan due to particular design advantages that favour one characteristic over another.

all of which have individual benefits (volume, pressure, speed, power, efficiency, etc.) but all of them will shift gases at the same rate based upon the input power. There are a number of fan types: impeller, axial, centrifugal, Sirocco, etc.

Pc fan sizes measured