Contrary to popular belief, air flow rate is not the best measure of fan performance. The most important factor governing whether a fan will perform adequately is air pressure.
Pressure measurements are important because this tells how well the fan can move air from one place to another. Pressure is what overcomes the resistance of the air in order for it to move. If a fan is operated in free space, there is no obstruction to the air entering or leaving the fan. Its air flow should be at a maximum because there is no resistance to the air moving freely. If a duct is fitted to either the inlet or outlet, then the resistance of the air moving through the duct has to be overcome by the fan. It is pressure that overcomes this resistance.
When a fan is unducted and empties directly into a ceiling space, there is still resistance to be overcome. There is resistance to air entering the room and resistance to air leaving the roof space. It is important for the fan to generate sufficient pressure to overcome this combined resistance.
If a fan cannot generate enough pressure to make the air move, it will cavitate. Cavitation is when the blades chop through the air making it turbulent but without making it move beyond the fan outlet.
The VORTX use an advanced aerodynamic design to prevent cavitation and ensure that the fan can generate good pressure under a wide variety of conditions. The rotor blades and the stator vanes have been developed and modelled using computer aided design software. Special manufacturing techniques had to be developed to make these unique shapes. VORTX exhaust fans are available from Hunter Pacific .
The VORTX motor is sealed and fitted with ball bearings for long life and reliability. Speed control is provided to suit different applications. Low speed is suitable for continuous operation when ventilating rooms, whereas normal speed provides true extraction capacity. Boost mode is recommended to clear a room in the shortest possible time and is a unique feature of VORTX.