Vaneaxial Fans Type J (Models VJ, VJBD) - Aerovent

Blade AdjustmentHow It WorksThe patented Type "J" blade design provides the customerwith the ability to modify the blade angle in order to vary theperformance without loosening or removing any hardware.The resilient O-ring acts like a spring (producing frictionbetween hub and blades so the blade does not turn duringoperation), to preload the blade retaining disc and hubarrangement, while providing a centering force. It insures aproper fit of blade and hub. The O-ring also minimizes vibrationbetween the blades and hub, reducing the potential formaterial fatigue.The angle of the blades can be adjusted by hand or byusing a blade adjusting tool. With the fan propeller in motion,the friction between the blade retaining disc and the hub itselfis increased due to centrifugal force which holds the bladefirm and prevents any undesired change in blade angle.HubBladeRetainingDiscBladeResilientO-RingBlade AnglesThe blade angle for Type "J" fans ranges from 30° to 50° andis indexed in the area where blade and hub meet. The ratingsdisplayed in this catalog indicate the specific blade anglerequired, and the blade should be set accordingly.Blade set at 30° angleHow To AdjustBlade angle adjustment is a quick and simple procedure andcan be accomplished through the fan inlet when convenient.When access to the propeller is not available from the faninlet, the blades can be adjusted through the propeller areaaccess door by hand or by using a blade adjusting tool. Thepropeller area access door and adjusting tool are provided withour fans as standard.When adjusting the blade angle, care must be taken not tooverload the fan motor. Refer to the fan curves or consult yourAerovent representative to assure the fan is properly applied.Further care must be taken to be sure that all fan blades areadjusted to the same blade angle, thus insuring proper airflowcharacteristics and balance.Blade angle adjustment tool4Aerovent Bulletin 476