"Cross Flow Fan" after entering the air base, driven by the motor, and then through the base layer above the hidden blades blowing up. This layer is horizontally rotating blades, installed after the wind box on the outside can not see. After the motor and fan role, it has formed a certain stream of air into the interior cavity of the air box. Note that the internal wind box is a special cavity structure, rather than a simple solid metal box. Can be seen from the following schematic cross-section of the cavity toward the positive direction of the fan frame of thin air, completely closed in the opposite direction thick sheet metal wrapped after leaving a narrow gap in a circle, this gap It is the outlet.