Series 91 Adjustable Pitch Fans offer top performance with low tip speed and sound ratings. The unit can reach a maximum total efficiency of 75% (average efficiency for this design is 65%). Efficient operation ranges from free air through ¾" SP.
Standard sizes are 7 through 14', with four- or six-bladed assemblies. Air volume ranges from 50,000 to 500,000 CFM at free air. Angle changes in the field are easily made by loosening the clamps at each blade shank and rotating the blade to the correct angle.
All sizes are available in right-hand (clockwise) rotation only.
Fans are tested for sound and air ratings in Hartzell’s AMCA Accredited Laboratory in accordance with industry standards.
Additional Series 91 features:
- Suitable for temperatures up to 200°F, with high-temperature construction available for applications up to 350°F
- Sand-cast, aluminum airfoil blades, ground to satin finish for balance
- Welded steel hubs
- Taper lock bushing standard on all sizes
- Maximum tip speed of 11,000 FPM
- Hubs dynamically balanced at the factory prior to shipping
- Blades statically balanced against a master blade
- Supplied knocked down standard
- Special coatings and constructions available, including coatings for corrosive applications