Coolvent Technology

A Forced Draft Fan (FD Fan) is a type of industrial fan used to supply air into the furnace or combustion chamber of a boiler, heater, or kiln. It creates positive pressure, pushing fresh air from the atmosphere into the system to ensure efficient fuel combustion.

A Forced Draft Fan is typically installed at the inlet of a boiler or furnace. It forces air into the combustion chamber, overcoming resistance caused by fuel burning, heat exchangers, and exhaust paths. The air it supplies is necessary for the combustion of fuels like coal, oil, gas, or biomass.

FD Fans are usually centrifugal fans, meaning they use a rotating impeller to increase air pressure and move it into the system. The airflow they provide can be regulated to match the fuel input and load demand.

1. Fan Housing – Encloses the rotating impeller.

2. Impeller (Blades) – Spins to push air outward.

3. Motor – Powers the impeller.

4. Dampers/Inlet Guide Vanes – Control the volume of air.

5. Bearings and Shaft – Support rotation.

6. Inlet Filter (optional) – Cleans incoming air.

1. Ambient air enters the fan.

2. The impeller rotates, increasing air pressure and velocity.

3. Pressurized air is pushed into the furnace or boiler.

4. Air mixes with fuel for combustion.

5. Combustion gases are then expelled via chimney (often assisted by an Induced Draft Fan).

• Ensures adequate oxygen supply for fuel burning.

• Helps maintain flame stability.

• Enhances combustion efficiency.

• Supports higher thermal output and better fuel economy.

• Reduces unburned carbon losses.