Matched family of fan rotors for industrial ventilation system - has rotors of ascending diameter with blade number and geometry varied to produce range of air deliveries at constant pressure and rpm

摘要

A range of electric axial flow fans for ventilation systems offers a series of fan rotors of differing diameters which by selection enable the air delivery to be suited to purpose when coupled to a motor of given speed. The number of fan blades, their geometry, profile and pitch angle vary throughout the range of ascending diams. to achieve an almost constant static pressure independent of delivery. The graph has ordinates of static pressure in Pascals and abscissae in m3/sec and demonstrates the close control of pressure in a narrow band (a) for a family of rotor diams. (900 to 1600mm.) delivering 7 to 60 m3/sec at a constant 1470 rpm. USE/ADVANTAGE - Enables operating region of ventilation system to achieve required air delivery at acceptable static pressure without any subsequent change to drive motor rpm. System is also applicable to radial and cross-flow fan units.