Overview and Applications

The Chicago Blower Corporation's SQA and SQAD fans are engineered for versatile industrial and commercial uses such as supply air, clean air, forced air packaging, pneumatic conveying, aeration, and pressurizing. Fan sizes range from 8-3/4 to 44-1/2 inches, delivering volumes up to 55,000 CFM and pressures up to 15" W.G. Multiple arrangements (SQA 1, 8, 9; SQAD 4), construction classes (I, II, III), and discharge options (TH, BH, UB, DB) are available. All fans are AMCA licensed for performance assurance.

Design and Performance Features

• Airfoil Wheel Efficiency: Designed to improve efficiency, reduce energy consumption, and lower noise by generating smooth lifting airflow with a broad efficiency curve adaptable to pressure variations.
• Robust Construction: Heavy gauge steel housings welded by AWS-certified welders ensure durability and structural integrity; flanged housing edges enhance rigidity.
• Hyperbolic Wheel Cone: Exclusive spun steel cone promotes smooth, stable airflow across operating ranges.
• Precision Shafts: SAE 1045 carbon steel shafts are turned, ground, and polished for tight bearing and hub fit, operating at least 20% below first critical speed for reliability.
• Adjustable Motor Base: Arrangement 9 bases are pre-punched for common motor frames, featuring threaded belt tension adjustment with positive locking.
• Flanged Outlet and Adjustable Discharge: Pre-punched flanged outlets enable solid duct connections; housings rotate without disassembly to allow four discharge positions for installation flexibility.

Additional Features and Options

• Multiple inlet types: open, slip fit, and punched flanged.
• Companion flanges for inlet/outlet facilitate flange-to-flange duct connections.
• Outlet dampers with parallel or opposed blades for manual or automatic airflow control.
• Inlet Volume Control (IVC) offers precise air control and higher efficiency than outlet dampers, operable manually or automatically.
• Inlet boxes simplify duct connections when horizontal connections are impractical.
• Cast aluminum wheels available for select sizes and temperature ratings.
• Accessories include inlet screens, shaft seals (split steel/aluminum or leak-resistant contact seals), and shaft coolers for high-temperature applications (up to 650°F).
• Safety and maintenance features: shaft and bearing guards, extended grease fittings, fully enclosed belt guards with removable covers, quick-clamp access doors, housing drains, unitary bases with vibration isolators, and vibration T-rails.
• Spark resistant construction types B and C for temperatures up to 200°F and 650°F respectively.
• Special coatings available for corrosion resistance and stringent environmental conditions.

Performance Data and Selection Procedures

Fan capacity tables are based on standard air at 70°F and sea level. For other conditions, static pressure must be corrected using temperature and altitude correction factors before fan selection; brake horsepower (BHP) is corrected post-selection. Fan construction class is determined by verifying wheel and shaft maximum RPM and temperature deration factors. An example illustrates selection for a 15,000 CFM fan at 3" SP, 500°F, and 2500 ft altitude, demonstrating correction factor application, fan size selection, BHP correction, and class determination.

Tables and Data Highlights

• Table I: Temperature and altitude correction factors for static pressure and BHP adjustments.
• Table II: Maximum RPM limits at 70°F for various fan sizes and construction classes.
• Table III: Speed deration factors for steel wheels and shafts at elevated temperatures.
• Example performance: 24-1/2" fan at 8000 ACFM, 6" SP, 100°F, 800 ft altitude operates at 1677 RPM, requires 9.35 BHP, with 80.7% static efficiency and 2275 ft/min outlet velocity.
• Sound data per AMCA Standard 300 includes external sound power and sound pressure levels measured at 3 ft from the fan.

Graphs and Curves

Performance curves depict static pressure, power, and efficiency versus flow rate, emphasizing that operation left of the peak pressure curve is prohibited except during startup.

Software and Support

Chicago Blower offers fan selection software (fan.net) for precise sizing, performance curves, and sound data, with customer support available via their website.

Critical Information and Best Practices

• Always apply temperature and altitude corrections prior to fan selection.
• Verify maximum RPM limits for wheel and shaft to determine correct construction class.
• Prefer inlet volume control over outlet dampers for improved efficiency in variable load applications.
• Ensure proper installation using adjustable discharge positions and companion flanges.
• Consider special coatings and spark resistant construction for harsh environments.
• Facilitate maintenance with extended grease fittings, access doors, and removable guards.

Performance Data Tables

Extensive tabulated data relate RPM, CFM, and BHP for various blower sizes and outlet configurations. RPM typically ranges from 500 to over 4000, with BHP increasing alongside RPM and airflow. Data is segmented by outlet sizes (e.g., 1/4" to 10" SP and SPOV configurations), providing detailed performance metrics.

Operating Limits and Recommendations

• Maximum safe RPM values are specified per blower size and class (e.g., 4046 RPM for Size 12 1/4, 4280 RPM for Size 13 1/2).
• Maximum BHP is calculated using quadratic formulas based on RPM.
• For V-belt drives exceeding 3600 RPM, factory consultation is advised to ensure safe operation.

Installation and Performance Conditions

• Performance data is certified for installation type B (free inlet, ducted outlet).
• Ratings assume air density of 0.075 lbs/ft³, 70°F temperature, and sea level elevation.
• Power ratings exclude transmission losses; performance excludes accessory effects.

Key Parameters and Formulas

• Tip speed (FPM) is calculated as a constant multiplied by RPM (e.g., 3.46 × RPM for Size 12 1/4).
• Outlet areas are specified per blower size (e.g., 0.88 sq. ft. for Size 12 1/4).

Notes and Cautions

• Use performance data within specified installation and environmental conditions for accuracy.
• Consult factory for V-belt drives over 3600 RPM.
• Power and performance values are nominal and exclude accessory and transmission losses.

Technical Data Summary for Various Fan Sizes

Data covers fan sizes from 4" to over 44-1/2", detailing airflow, static pressure, RPM, BHP, tip speed, and outlet areas. Maximum safe speeds and power limits are provided by construction class. Sound level data per AMCA Standard 300 is included, with bearing life rated at a minimum of 75,000 hours, extendable based on operating conditions.

Mechanical and Operational Limits

• Maximum RPM limits vary by fan size and class (Class I, II, III).
• Power ratings exclude transmission losses and accessory effects.
• Tip speed and maximum BHP formulas enable calculation for custom RPM values.

Installation and Performance Notes

• Performance certified for installation type B.
• Sound levels are approximate; detailed sound power data available on request.
• Proper maintenance and monitoring of bearing life are critical for longevity.

Fan and Motor Dimensions, Configurations, and Specifications

• Fan sizes range from 8-3/4" to 59-1/2" with detailed shaft diameters, flange sizes, and overall dimensions.
• Motor frames include "U" and "T" types; unitary base sizes and weights are specified.
• Discharge positions and rotation directions are coded (TH, DB, UB, BH; CW or CCW) and grouped for clarity.
• Belt center dimensions include allowances for mounting and tensioning.
• Flange dimensions detailed for inlet and outlet connections.

Notes and Recommendations

• Dimensions are not for construction unless certified.
• Verify motor frame compatibility and discharge position before installation.
• Consult factory for special arrangements such as Arrangement 9H.
• Use provided belt center dimensions for proper belt installation.

Summary

This comprehensive technical document serves engineers and technicians by providing detailed performance data, mechanical specifications, operational limits, and best practices for Chicago Blower Corporation fans. It supports accurate fan selection, safe operation, efficient performance, and proper installation under defined environmental and application conditions.