Final answer:
The three main ways to control the airflow in a steam boiler are dampers, air registers, and variable-speed drives. Variable-Speed Drives: Variable-speed drives are used to control the speed of the fans that provide the airflow to the boiler. By varying the speed of the fans, the airflow can be adjusted to meet the changing demands of the boiler.
Step-by-step explanation:
The three main ways to control the airflow in a steam boiler are: Dampers: Dampers are devices that can be adjusted to control the amount of air entering the boiler. By adjusting the position of the dampers, the airflow can be increased or decreased as needed.
Air Registers: Air registers are adjustable openings that control the flow of air into specific areas of the boiler. By adjusting the size of the opening, the airflow to different sections of the boiler can be controlled. Variable-Speed Drives: Variable-speed drives are used to control the speed of the fans that provide the airflow to the boiler. By varying the speed of the fans, the airflow can be adjusted to meet the changing demands of the boiler.