Guide Specs

SERIES 31U BELT DRIVE UTILITY DUCT FAN, STEEL SK-880-31U NOVEMBER, 1997

The Belt Drive Utility Duct Fan, Steel shall be manufactured by Hartzell Fan, Inc.®, Series 31U. Standard sizes are 12" through 60".

The utility duct fan propeller shall be an airfoil design, cast of 319 aluminum in compliance with Federal Specification QQ-A-601E and ASTM B26. Propellers shall be retained on the fan shaft utilizing a split taper bushing.

Sizes 12" through 48" shall have self-formed flanges with slotted mounting holes. Sizes 54" and 60" shall have rolled steel flanges. Fan housing shall be minimum 12 gauge rolled commercial quality carbon steel, continuously welded in compliance with AWS D1.1 standard. Standard coating shall be an industrial grade air dry enamel paint.

The motor mounting base shall be adjustable to permit belt tensioning be adjustment of the motor position. Motor is to be available as an option with factory mounting as an option.

Fan shafts shall be ground and polished carbon steel. Bearings shall be located in a drive compartment on the negative pressure side of the propeller, drawing outside ambient air in and over the belts and bearings. Bearings shall be heavy duty, self-aligning ball bearing type mounted in pillow block housings. Bearings shall have extended lube lines and shall be relubricable for continuous service. Minimum L-50 bearing life at maximum catalog speed, horsepower, and static pressure: 350,000 hours (horizontal). Minimum L-50 bearing life at maximum catalog speed, horsepower, and static pressure: 250,000 hours (vertical). Constant and variable pitch drive sheaves shall be available options on the fans. V-belt drives when supplied shall be supplied as components for field mounting with factory mounting as an option. Belts shall be heat, oil and static resistant, "V" type, and sized for continuous service.

The fan assembly shall be dynamically balanced at the Hartzell factory prior to shipping. Fans shall be balanced in accordance with AMCA Standard 204-96, fan application category BV-3 (comparable to Grade G6.3). Fans shall be manufactured in accordance with Hartzell's standard quality assurance procedures. Fan performance shall be based on tests conducted in Hartzell's AMCA accredited test laboratory and in accordance with the latest revision of AMCA Standard 210 for air performance and AMCA Standard 300 for sound. Fans shall be licensed to bear the AMCA Certified Sound and Air Performance Rating Seal.