"AC Fan" cross-section generally airfoil. Leaves can be fixed location or around the blade pitch angle or vertical axis of rotation, blades and airflow is not adjustable or adjustable to change the angle or pitch of the blades is one of the main advantages of axial fans. Small blade pitch angles produce lower flows while increasing the pitch may result in higher traffic. By using this principle in order to achieve better results, the user is also the most important principle, but in order to allow the fan to better play the role of the latter part of the maintenance work must not relax, every fan only components can properly play a role, in order to better ensure the use of the fan.