An in-line centrifugal fan is a type of fan that is used to move air or other gases in a duct system. It works by using centrifugal force to draw air in at one end of the fan and then pushing it out the other end. The fan is typically mounted in the middle of the duct system and is powered by an electric motor. The fan blades are designed to spin at high speeds, creating a powerful airflow. This airflow is then directed through the duct system, providing ventilation and air circulation. In-line centrifugal fans are commonly used in HVAC systems, ventilation systems, and industrial applications. They are also used in many other applications where air needs to be moved quickly and efficiently. In-line centrifugal fans are highly efficient and reliable, making them a popular choice for many applications.