In-line fans are characterized by which configuration?

• A. Motor located outside the airstream and belts/pulleys protected by a greasetight housing
• B. Motor located outside the airstream with no protective housing
• C. Motor located inside the airstream
• D. Motor located inside with aftercooler

Answer: (A)

Inline fans are designed to minimize ignition risk in grease-laden kitchen exhaust. The best configuration places the motor outside the airstream with belts and pulleys protected inside a grease-tight housing. This keeps the motor and drive components away from hot, flammable vapors and grease, reducing the chance of fire and making maintenance easier because the moving parts are sealed from the duct. Placing the motor inside the airstream would expose electrical parts to heat and grease, raising fire risk and complicating cleaning. A setup with no protective housing isn’t as safe because grease can reach belts and pulleys, and using an aftercooler inside the housing isn’t a standard, practical arrangement for this purpose.