The induced draft fan is installed on the exhaust side of the boiler system. It pulls combustion products through the downstream flue-gas path and helps keep the furnace operating under a controlled negative-pressure condition.
The fan cannot be selected only by boiler capacity, fan size or motor power. Actual performance depends on the required operating airflow and the total resistance created by the complete system.
For a new boiler project or replacement fan, Qiyue Fan reviews the boiler duty, fuel, gas temperature, dust-control equipment, duct arrangement, existing operating point and installation limitations before suggesting a suitable model direction.
The boiler ID fan must deliver the target airflow after all downstream resistance has been included. A free-air airflow value or motor-power comparison cannot represent the real operating point.
Dust accumulation, damper position and filter condition may change resistance during operation. A practical design therefore needs a confirmed design point and a reasonable operating margin.
For a new project, provide the boiler duty and planned exhaust-system route. Airflow and pressure should be based on the complete resistance calculation.
Original fan data and current operating problems help determine whether the new unit should match the existing duty or correct a selection mismatch.
It pulls flue gas through the boiler exhaust route and helps maintain the required furnace negative pressure. It must provide the target airflow while overcoming the total resistance of the connected system.
The required pressure should include duct friction, elbows, transitions, dampers, dust collector or treatment equipment, chimney and discharge losses. The fan must then be checked at the required airflow.
It is normally installed on the downstream exhaust side, often after the main dust-removal equipment and before the chimney. Final location depends on the boiler process and system design.
Boiler capacity is useful for preliminary screening, but final selection also requires airflow, total pressure, temperature, dust condition, system resistance and installation arrangement.
Send the original fan and motor nameplates, operating data, inlet and outlet sizes, rotation, outlet angle, foundation dimensions, site photos and the current operating problem.
The suitable series depends on the operating point and project conditions. Send boiler capacity, airflow, pressure, temperature, dust collector, flue-gas condition, drive requirement and installation layout for preliminary matching.