Technical guide CHOOSING THE APPROPRIATE FAN OR BLOWER WITH THE WORKING POINT Example: Working point: 22 l/s at 1,8 mm H2O Fig.2 OPTIMISING FAN SELECTION If the air requirement is high, and available space limited, it is possible to double the airflow at free delivery by putting two fans in parallel or to increase the pressure by putting two fans in series. 6,0 Static Pressure (mm H2O) The combination of necessary airflow and static pressure gives a value which is called working point. It is now very easy to choose the appropriate fan or blower, by selecting a model in the catalogue, which curve meets the working point (see fig 2). 50 Hz 60 Hz Load curve 5,0 4,0 3,0 2,0 Working-point 1,0 0,0 0 5 10 15 20 25 30 35 40 Airflow (I/s) The noise level will then increase by approximately 3dBA depending on the fan model. rtant Impo e ! notic The next chapter shows the benefits of the different fan designs. Values indicated in this catalogue are based on free delivery (no pressure value) and shutoff (no flow condition). About fans performance: II - AERODYNAMIC FAN TYPES These drawings describe the air direction for each aerodynamic fan type. AXIAL FANS BACKWARD CURVED FANS Benefits: Benefits: - High airflow - Low static pressure - Motor cooled by the flow - Low noise - Best design for combination of high airflow and high static pressure Fig.3 CENTRIFUGAL BLOWERS Fig.5 CROSS FLOW FANS Benefits: Benefits: - Low airflow - High static pressure - Best design to create over or under pressure - High static pressure - Best design to spread the airflow on a wide surface Fig.4 Website: www.etrinet.com • E-mail: [email protected] 6 Fig.6